From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: Steven Rostedt <rostedt@goodmis.org>,
LKML <linux-kernel@vger.kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@elte.hu>,
Frederic Weisbecker <fweisbec@gmail.com>,
Thomas Gleixner <tglx@linutronix.de>,
Christoph Hellwig <hch@lst.de>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Li Zefan <lizf@cn.fujitsu.com>,
Lai Jiangshan <laijs@cn.fujitsu.com>,
Johannes Berg <johannes.berg@intel.com>,
Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
Arnaldo Carvalho de Melo <acme@infradead.org>,
Tom Zanussi <tzanussi@gmail.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
Andi Kleen <andi@firstfloor.org>
Subject: [patch 11/20] Ftrace ring buffer renaming
Date: Fri, 09 Jul 2010 18:57:38 -0400 [thread overview]
Message-ID: <20100709225817.411237590@efficios.com> (raw)
In-Reply-To: 20100709225727.312232266@efficios.com
[-- Attachment #1: ftrace-ring-buffer.patch --]
[-- Type: text/plain, Size: 317870 bytes --]
Rename ring_buffer_* to ftrace_ring_buffer_* everywhere. This is a first step in
the conversion of the ftrace ring buffer into a client of the generic ring
buffer library.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---
drivers/oprofile/cpu_buffer.c | 30
drivers/oprofile/cpu_buffer.h | 2
include/linux/ftrace_event.h | 24
include/linux/ftrace_ring_buffer.h | 196 +
include/linux/kernel.h | 2
include/linux/oprofile.h | 2
include/linux/ring_buffer.h | 196 -
include/trace/ftrace.h | 12
kernel/trace/Kconfig | 12
kernel/trace/Makefile | 4
kernel/trace/blktrace.c | 12
kernel/trace/ftrace_ring_buffer.c | 4022 ++++++++++++++++++++++++++++
kernel/trace/ftrace_ring_buffer_benchmark.c | 488 +++
kernel/trace/ring_buffer.c | 4022 ----------------------------
kernel/trace/ring_buffer_benchmark.c | 488 ---
kernel/trace/trace.c | 262 -
kernel/trace/trace.h | 30
kernel/trace/trace_branch.c | 8
kernel/trace/trace_events.c | 12
kernel/trace/trace_functions.c | 2
kernel/trace/trace_functions_graph.c | 30
kernel/trace/trace_kprobe.c | 12
kernel/trace/trace_ksym.c | 6
kernel/trace/trace_mmiotrace.c | 14
kernel/trace/trace_sched_switch.c | 14
kernel/trace/trace_selftest.c | 8
kernel/trace/trace_syscalls.c | 12
27 files changed, 4961 insertions(+), 4961 deletions(-)
Index: linux.trees.git/include/linux/ftrace_event.h
===================================================================
--- linux.trees.git.orig/include/linux/ftrace_event.h 2010-07-09 18:08:14.000000000 -0400
+++ linux.trees.git/include/linux/ftrace_event.h 2010-07-09 18:08:47.000000000 -0400
@@ -1,7 +1,7 @@
#ifndef _LINUX_FTRACE_EVENT_H
#define _LINUX_FTRACE_EVENT_H
-#include <linux/ring_buffer.h>
+#include <linux/ftrace_ring_buffer.h>
#include <linux/trace_seq.h>
#include <linux/percpu.h>
#include <linux/hardirq.h>
@@ -55,7 +55,7 @@ struct trace_iterator {
void *private;
int cpu_file;
struct mutex mutex;
- struct ring_buffer_iter *buffer_iter[NR_CPUS];
+ struct ftrace_ring_buffer_iter *buffer_iter[NR_CPUS];
unsigned long iter_flags;
/* The below is zeroed out in pipe_read */
@@ -106,18 +106,18 @@ enum print_line_t {
void tracing_generic_entry_update(struct trace_entry *entry,
unsigned long flags,
int pc);
-struct ring_buffer_event *
-trace_current_buffer_lock_reserve(struct ring_buffer **current_buffer,
+struct ftrace_ring_buffer_event *
+trace_current_buffer_lock_reserve(struct ftrace_ring_buffer **current_buffer,
int type, unsigned long len,
unsigned long flags, int pc);
-void trace_current_buffer_unlock_commit(struct ring_buffer *buffer,
- struct ring_buffer_event *event,
+void trace_current_buffer_unlock_commit(struct ftrace_ring_buffer *buffer,
+ struct ftrace_ring_buffer_event *event,
unsigned long flags, int pc);
-void trace_nowake_buffer_unlock_commit(struct ring_buffer *buffer,
- struct ring_buffer_event *event,
+void trace_nowake_buffer_unlock_commit(struct ftrace_ring_buffer *buffer,
+ struct ftrace_ring_buffer_event *event,
unsigned long flags, int pc);
-void trace_current_buffer_discard_commit(struct ring_buffer *buffer,
- struct ring_buffer_event *event);
+void trace_current_buffer_discard_commit(struct ftrace_ring_buffer *buffer,
+ struct ftrace_ring_buffer_event *event);
void tracing_record_cmdline(struct task_struct *tsk);
@@ -199,10 +199,10 @@ struct ftrace_event_call {
extern void destroy_preds(struct ftrace_event_call *call);
extern int filter_match_preds(struct event_filter *filter, void *rec);
-extern int filter_current_check_discard(struct ring_buffer *buffer,
+extern int filter_current_check_discard(struct ftrace_ring_buffer *buffer,
struct ftrace_event_call *call,
void *rec,
- struct ring_buffer_event *event);
+ struct ftrace_ring_buffer_event *event);
enum {
FILTER_OTHER = 0,
Index: linux.trees.git/include/linux/ftrace_ring_buffer.h
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux.trees.git/include/linux/ftrace_ring_buffer.h 2010-07-09 18:08:47.000000000 -0400
@@ -0,0 +1,196 @@
+#ifndef _LINUX_FTRACE_RING_BUFFER_H
+#define _LINUX_FTRACE_RING_BUFFER_H
+
+#include <linux/kmemcheck.h>
+#include <linux/mm.h>
+#include <linux/seq_file.h>
+
+struct ftrace_ring_buffer;
+struct ftrace_ring_buffer_iter;
+
+/*
+ * Don't refer to this struct directly, use functions below.
+ */
+struct ftrace_ring_buffer_event {
+ kmemcheck_bitfield_begin(bitfield);
+ u32 type_len:5, time_delta:27;
+ kmemcheck_bitfield_end(bitfield);
+
+ u32 array[];
+};
+
+/**
+ * enum ftrace_ring_buffer_type - internal ring buffer types
+ *
+ * @RINGBUF_TYPE_PADDING: Left over page padding or discarded event
+ * If time_delta is 0:
+ * array is ignored
+ * size is variable depending on how much
+ * padding is needed
+ * If time_delta is non zero:
+ * array[0] holds the actual length
+ * size = 4 + length (bytes)
+ *
+ * @RINGBUF_TYPE_TIME_EXTEND: Extend the time delta
+ * array[0] = time delta (28 .. 59)
+ * size = 8 bytes
+ *
+ * @RINGBUF_TYPE_TIME_STAMP: Sync time stamp with external clock
+ * array[0] = tv_nsec
+ * array[1..2] = tv_sec
+ * size = 16 bytes
+ *
+ * <= @RINGBUF_TYPE_DATA_TYPE_LEN_MAX:
+ * Data record
+ * If type_len is zero:
+ * array[0] holds the actual length
+ * array[1..(length+3)/4] holds data
+ * size = 4 + length (bytes)
+ * else
+ * length = type_len << 2
+ * array[0..(length+3)/4-1] holds data
+ * size = 4 + length (bytes)
+ */
+enum ftrace_ring_buffer_type {
+ RINGBUF_TYPE_DATA_TYPE_LEN_MAX = 28,
+ RINGBUF_TYPE_PADDING,
+ RINGBUF_TYPE_TIME_EXTEND,
+ /* FIXME: RINGBUF_TYPE_TIME_STAMP not implemented */
+ RINGBUF_TYPE_TIME_STAMP,
+};
+
+unsigned ftrace_ring_buffer_event_length(struct ftrace_ring_buffer_event *event);
+void *ftrace_ring_buffer_event_data(struct ftrace_ring_buffer_event *event);
+
+/**
+ * ftrace_ring_buffer_event_time_delta - return the delta timestamp of the event
+ * @event: the event to get the delta timestamp of
+ *
+ * The delta timestamp is the 27 bit timestamp since the last event.
+ */
+static inline unsigned
+ftrace_ring_buffer_event_time_delta(struct ftrace_ring_buffer_event *event)
+{
+ return event->time_delta;
+}
+
+/*
+ * ftrace_ring_buffer_discard_commit will remove an event that has not
+ * ben committed yet. If this is used, then ftrace_ring_buffer_unlock_commit
+ * must not be called on the discarded event. This function
+ * will try to remove the event from the ring buffer completely
+ * if another event has not been written after it.
+ *
+ * Example use:
+ *
+ * if (some_condition)
+ * ftrace_ring_buffer_discard_commit(buffer, event);
+ * else
+ * ftrace_ring_buffer_unlock_commit(buffer, event);
+ */
+void ftrace_ring_buffer_discard_commit(struct ftrace_ring_buffer *buffer,
+ struct ftrace_ring_buffer_event *event);
+
+/*
+ * size is in bytes for each per CPU buffer.
+ */
+struct ftrace_ring_buffer *
+__ftrace_ring_buffer_alloc(unsigned long size, unsigned flags, struct lock_class_key *key);
+
+/*
+ * Because the ring buffer is generic, if other users of the ring buffer get
+ * traced by ftrace, it can produce lockdep warnings. We need to keep each
+ * ring buffer's lock class separate.
+ */
+#define ftrace_ring_buffer_alloc(size, flags) \
+({ \
+ static struct lock_class_key __key; \
+ __ftrace_ring_buffer_alloc((size), (flags), &__key); \
+})
+
+void ftrace_ring_buffer_free(struct ftrace_ring_buffer *buffer);
+
+int ftrace_ring_buffer_resize(struct ftrace_ring_buffer *buffer, unsigned long size);
+
+struct ftrace_ring_buffer_event *ftrace_ring_buffer_lock_reserve(struct ftrace_ring_buffer *buffer,
+ unsigned long length);
+int ftrace_ring_buffer_unlock_commit(struct ftrace_ring_buffer *buffer,
+ struct ftrace_ring_buffer_event *event);
+int ftrace_ring_buffer_write(struct ftrace_ring_buffer *buffer,
+ unsigned long length, void *data);
+
+struct ftrace_ring_buffer_event *
+ftrace_ring_buffer_peek(struct ftrace_ring_buffer *buffer, int cpu, u64 *ts,
+ unsigned long *lost_events);
+struct ftrace_ring_buffer_event *
+ftrace_ring_buffer_consume(struct ftrace_ring_buffer *buffer, int cpu, u64 *ts,
+ unsigned long *lost_events);
+
+struct ftrace_ring_buffer_iter *
+ftrace_ring_buffer_read_prepare(struct ftrace_ring_buffer *buffer, int cpu);
+void ftrace_ring_buffer_read_prepare_sync(void);
+void ftrace_ring_buffer_read_start(struct ftrace_ring_buffer_iter *iter);
+void ftrace_ring_buffer_read_finish(struct ftrace_ring_buffer_iter *iter);
+
+struct ftrace_ring_buffer_event *
+ftrace_ring_buffer_iter_peek(struct ftrace_ring_buffer_iter *iter, u64 *ts);
+struct ftrace_ring_buffer_event *
+ftrace_ring_buffer_read(struct ftrace_ring_buffer_iter *iter, u64 *ts);
+void ftrace_ring_buffer_iter_reset(struct ftrace_ring_buffer_iter *iter);
+int ftrace_ring_buffer_iter_empty(struct ftrace_ring_buffer_iter *iter);
+
+unsigned long ftrace_ring_buffer_size(struct ftrace_ring_buffer *buffer);
+
+void ftrace_ring_buffer_reset_cpu(struct ftrace_ring_buffer *buffer, int cpu);
+void ftrace_ring_buffer_reset(struct ftrace_ring_buffer *buffer);
+
+#ifdef CONFIG_FTRACE_RING_BUFFER_ALLOW_SWAP
+int ftrace_ring_buffer_swap_cpu(struct ftrace_ring_buffer *buffer_a,
+ struct ftrace_ring_buffer *buffer_b, int cpu);
+#else
+static inline int
+ftrace_ring_buffer_swap_cpu(struct ftrace_ring_buffer *buffer_a,
+ struct ftrace_ring_buffer *buffer_b, int cpu)
+{
+ return -ENODEV;
+}
+#endif
+
+int ftrace_ring_buffer_empty(struct ftrace_ring_buffer *buffer);
+int ftrace_ring_buffer_empty_cpu(struct ftrace_ring_buffer *buffer, int cpu);
+
+void ftrace_ring_buffer_record_disable(struct ftrace_ring_buffer *buffer);
+void ftrace_ring_buffer_record_enable(struct ftrace_ring_buffer *buffer);
+void ftrace_ring_buffer_record_disable_cpu(struct ftrace_ring_buffer *buffer, int cpu);
+void ftrace_ring_buffer_record_enable_cpu(struct ftrace_ring_buffer *buffer, int cpu);
+
+unsigned long ftrace_ring_buffer_entries(struct ftrace_ring_buffer *buffer);
+unsigned long ftrace_ring_buffer_overruns(struct ftrace_ring_buffer *buffer);
+unsigned long ftrace_ring_buffer_entries_cpu(struct ftrace_ring_buffer *buffer, int cpu);
+unsigned long ftrace_ring_buffer_overrun_cpu(struct ftrace_ring_buffer *buffer, int cpu);
+unsigned long ftrace_ring_buffer_commit_overrun_cpu(struct ftrace_ring_buffer *buffer, int cpu);
+
+u64 ftrace_ring_buffer_time_stamp(struct ftrace_ring_buffer *buffer, int cpu);
+void ftrace_ring_buffer_normalize_time_stamp(struct ftrace_ring_buffer *buffer,
+ int cpu, u64 *ts);
+void ftrace_ring_buffer_set_clock(struct ftrace_ring_buffer *buffer,
+ u64 (*clock)(void));
+
+size_t ftrace_ring_buffer_page_len(void *page);
+
+
+void *ftrace_ring_buffer_alloc_read_page(struct ftrace_ring_buffer *buffer);
+void ftrace_ring_buffer_free_read_page(struct ftrace_ring_buffer *buffer, void *data);
+int ftrace_ring_buffer_read_page(struct ftrace_ring_buffer *buffer, void **data_page,
+ size_t len, int cpu, int full);
+
+struct trace_seq;
+
+int ftrace_ring_buffer_print_entry_header(struct trace_seq *s);
+int ftrace_ring_buffer_print_page_header(struct trace_seq *s);
+
+enum ftrace_ring_buffer_flags {
+ RB_FL_OVERWRITE = 1 << 0,
+};
+
+#endif /* _LINUX_FTRACE_RING_BUFFER_H */
Index: linux.trees.git/include/linux/ring_buffer.h
===================================================================
--- linux.trees.git.orig/include/linux/ring_buffer.h 2010-07-09 18:08:14.000000000 -0400
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1,196 +0,0 @@
-#ifndef _LINUX_RING_BUFFER_H
-#define _LINUX_RING_BUFFER_H
-
-#include <linux/kmemcheck.h>
-#include <linux/mm.h>
-#include <linux/seq_file.h>
-
-struct ring_buffer;
-struct ring_buffer_iter;
-
-/*
- * Don't refer to this struct directly, use functions below.
- */
-struct ring_buffer_event {
- kmemcheck_bitfield_begin(bitfield);
- u32 type_len:5, time_delta:27;
- kmemcheck_bitfield_end(bitfield);
-
- u32 array[];
-};
-
-/**
- * enum ring_buffer_type - internal ring buffer types
- *
- * @RINGBUF_TYPE_PADDING: Left over page padding or discarded event
- * If time_delta is 0:
- * array is ignored
- * size is variable depending on how much
- * padding is needed
- * If time_delta is non zero:
- * array[0] holds the actual length
- * size = 4 + length (bytes)
- *
- * @RINGBUF_TYPE_TIME_EXTEND: Extend the time delta
- * array[0] = time delta (28 .. 59)
- * size = 8 bytes
- *
- * @RINGBUF_TYPE_TIME_STAMP: Sync time stamp with external clock
- * array[0] = tv_nsec
- * array[1..2] = tv_sec
- * size = 16 bytes
- *
- * <= @RINGBUF_TYPE_DATA_TYPE_LEN_MAX:
- * Data record
- * If type_len is zero:
- * array[0] holds the actual length
- * array[1..(length+3)/4] holds data
- * size = 4 + length (bytes)
- * else
- * length = type_len << 2
- * array[0..(length+3)/4-1] holds data
- * size = 4 + length (bytes)
- */
-enum ring_buffer_type {
- RINGBUF_TYPE_DATA_TYPE_LEN_MAX = 28,
- RINGBUF_TYPE_PADDING,
- RINGBUF_TYPE_TIME_EXTEND,
- /* FIXME: RINGBUF_TYPE_TIME_STAMP not implemented */
- RINGBUF_TYPE_TIME_STAMP,
-};
-
-unsigned ring_buffer_event_length(struct ring_buffer_event *event);
-void *ring_buffer_event_data(struct ring_buffer_event *event);
-
-/**
- * ring_buffer_event_time_delta - return the delta timestamp of the event
- * @event: the event to get the delta timestamp of
- *
- * The delta timestamp is the 27 bit timestamp since the last event.
- */
-static inline unsigned
-ring_buffer_event_time_delta(struct ring_buffer_event *event)
-{
- return event->time_delta;
-}
-
-/*
- * ring_buffer_discard_commit will remove an event that has not
- * ben committed yet. If this is used, then ring_buffer_unlock_commit
- * must not be called on the discarded event. This function
- * will try to remove the event from the ring buffer completely
- * if another event has not been written after it.
- *
- * Example use:
- *
- * if (some_condition)
- * ring_buffer_discard_commit(buffer, event);
- * else
- * ring_buffer_unlock_commit(buffer, event);
- */
-void ring_buffer_discard_commit(struct ring_buffer *buffer,
- struct ring_buffer_event *event);
-
-/*
- * size is in bytes for each per CPU buffer.
- */
-struct ring_buffer *
-__ring_buffer_alloc(unsigned long size, unsigned flags, struct lock_class_key *key);
-
-/*
- * Because the ring buffer is generic, if other users of the ring buffer get
- * traced by ftrace, it can produce lockdep warnings. We need to keep each
- * ring buffer's lock class separate.
- */
-#define ring_buffer_alloc(size, flags) \
-({ \
- static struct lock_class_key __key; \
- __ring_buffer_alloc((size), (flags), &__key); \
-})
-
-void ring_buffer_free(struct ring_buffer *buffer);
-
-int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size);
-
-struct ring_buffer_event *ring_buffer_lock_reserve(struct ring_buffer *buffer,
- unsigned long length);
-int ring_buffer_unlock_commit(struct ring_buffer *buffer,
- struct ring_buffer_event *event);
-int ring_buffer_write(struct ring_buffer *buffer,
- unsigned long length, void *data);
-
-struct ring_buffer_event *
-ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts,
- unsigned long *lost_events);
-struct ring_buffer_event *
-ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts,
- unsigned long *lost_events);
-
-struct ring_buffer_iter *
-ring_buffer_read_prepare(struct ring_buffer *buffer, int cpu);
-void ring_buffer_read_prepare_sync(void);
-void ring_buffer_read_start(struct ring_buffer_iter *iter);
-void ring_buffer_read_finish(struct ring_buffer_iter *iter);
-
-struct ring_buffer_event *
-ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts);
-struct ring_buffer_event *
-ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts);
-void ring_buffer_iter_reset(struct ring_buffer_iter *iter);
-int ring_buffer_iter_empty(struct ring_buffer_iter *iter);
-
-unsigned long ring_buffer_size(struct ring_buffer *buffer);
-
-void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu);
-void ring_buffer_reset(struct ring_buffer *buffer);
-
-#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
-int ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
- struct ring_buffer *buffer_b, int cpu);
-#else
-static inline int
-ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
- struct ring_buffer *buffer_b, int cpu)
-{
- return -ENODEV;
-}
-#endif
-
-int ring_buffer_empty(struct ring_buffer *buffer);
-int ring_buffer_empty_cpu(struct ring_buffer *buffer, int cpu);
-
-void ring_buffer_record_disable(struct ring_buffer *buffer);
-void ring_buffer_record_enable(struct ring_buffer *buffer);
-void ring_buffer_record_disable_cpu(struct ring_buffer *buffer, int cpu);
-void ring_buffer_record_enable_cpu(struct ring_buffer *buffer, int cpu);
-
-unsigned long ring_buffer_entries(struct ring_buffer *buffer);
-unsigned long ring_buffer_overruns(struct ring_buffer *buffer);
-unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu);
-unsigned long ring_buffer_overrun_cpu(struct ring_buffer *buffer, int cpu);
-unsigned long ring_buffer_commit_overrun_cpu(struct ring_buffer *buffer, int cpu);
-
-u64 ring_buffer_time_stamp(struct ring_buffer *buffer, int cpu);
-void ring_buffer_normalize_time_stamp(struct ring_buffer *buffer,
- int cpu, u64 *ts);
-void ring_buffer_set_clock(struct ring_buffer *buffer,
- u64 (*clock)(void));
-
-size_t ring_buffer_page_len(void *page);
-
-
-void *ring_buffer_alloc_read_page(struct ring_buffer *buffer);
-void ring_buffer_free_read_page(struct ring_buffer *buffer, void *data);
-int ring_buffer_read_page(struct ring_buffer *buffer, void **data_page,
- size_t len, int cpu, int full);
-
-struct trace_seq;
-
-int ring_buffer_print_entry_header(struct trace_seq *s);
-int ring_buffer_print_page_header(struct trace_seq *s);
-
-enum ring_buffer_flags {
- RB_FL_OVERWRITE = 1 << 0,
-};
-
-#endif /* _LINUX_RING_BUFFER_H */
Index: linux.trees.git/kernel/trace/Kconfig
===================================================================
--- linux.trees.git.orig/kernel/trace/Kconfig 2010-07-09 18:08:46.000000000 -0400
+++ linux.trees.git/kernel/trace/Kconfig 2010-07-09 18:08:47.000000000 -0400
@@ -52,7 +52,7 @@ config HAVE_SYSCALL_TRACEPOINTS
config TRACER_MAX_TRACE
bool
-config RING_BUFFER
+config FTRACE_RING_BUFFER
bool
config FTRACE_NMI_ENTER
@@ -67,7 +67,7 @@ config EVENT_TRACING
config CONTEXT_SWITCH_TRACER
bool
-config RING_BUFFER_ALLOW_SWAP
+config FTRACE_RING_BUFFER_ALLOW_SWAP
bool
help
Allow the use of ring_buffer_swap_cpu.
@@ -86,7 +86,7 @@ config TRACE_CLOCK_STANDALONE
config TRACING
bool
select DEBUG_FS
- select RING_BUFFER
+ select FTRACE_RING_BUFFER
select STACKTRACE if STACKTRACE_SUPPORT
select TRACEPOINTS
select NOP_TRACER
@@ -160,7 +160,7 @@ config IRQSOFF_TRACER
select TRACE_IRQFLAGS
select GENERIC_TRACER
select TRACER_MAX_TRACE
- select RING_BUFFER_ALLOW_SWAP
+ select FTRACE_RING_BUFFER_ALLOW_SWAP
help
This option measures the time spent in irqs-off critical
sections, with microsecond accuracy.
@@ -182,7 +182,7 @@ config PREEMPT_TRACER
depends on PREEMPT
select GENERIC_TRACER
select TRACER_MAX_TRACE
- select RING_BUFFER_ALLOW_SWAP
+ select FTRACE_RING_BUFFER_ALLOW_SWAP
help
This option measures the time spent in preemption-off critical
sections, with microsecond accuracy.
@@ -498,7 +498,7 @@ config MMIOTRACE_TEST
config RING_BUFFER_BENCHMARK
tristate "Ring buffer benchmark stress tester"
- depends on RING_BUFFER
+ depends on FTRACE_RING_BUFFER
help
This option creates a test to stress the ring buffer and benchmark it.
It creates its own ring buffer such that it will not interfere with
Index: linux.trees.git/kernel/trace/Makefile
===================================================================
--- linux.trees.git.orig/kernel/trace/Makefile 2010-07-09 18:08:14.000000000 -0400
+++ linux.trees.git/kernel/trace/Makefile 2010-07-09 18:08:47.000000000 -0400
@@ -22,8 +22,8 @@ endif
obj-y += trace_clock.o
obj-$(CONFIG_FUNCTION_TRACER) += libftrace.o
-obj-$(CONFIG_RING_BUFFER) += ring_buffer.o
-obj-$(CONFIG_RING_BUFFER_BENCHMARK) += ring_buffer_benchmark.o
+obj-$(CONFIG_FTRACE_RING_BUFFER) += ftrace_ring_buffer.o
+obj-$(CONFIG_RING_BUFFER_BENCHMARK) += ftrace_ring_buffer_benchmark.o
obj-$(CONFIG_TRACING) += trace.o
obj-$(CONFIG_TRACING) += trace_output.o
Index: linux.trees.git/kernel/trace/ftrace_ring_buffer.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux.trees.git/kernel/trace/ftrace_ring_buffer.c 2010-07-09 18:08:47.000000000 -0400
@@ -0,0 +1,4022 @@
+/*
+ * Generic ring buffer
+ *
+ * Copyright (C) 2008 Steven Rostedt <srostedt@redhat.com>
+ */
+#include <linux/ftrace_ring_buffer.h>
+#include <linux/trace_clock.h>
+#include <linux/ftrace_irq.h>
+#include <linux/spinlock.h>
+#include <linux/debugfs.h>
+#include <linux/uaccess.h>
+#include <linux/hardirq.h>
+#include <linux/kmemcheck.h>
+#include <linux/module.h>
+#include <linux/percpu.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/hash.h>
+#include <linux/list.h>
+#include <linux/cpu.h>
+#include <linux/fs.h>
+
+#include <asm/local.h>
+#include "trace.h"
+
+/*
+ * The ring buffer header is special. We must manually up keep it.
+ */
+int ftrace_ring_buffer_print_entry_header(struct trace_seq *s)
+{
+ int ret;
+
+ ret = trace_seq_printf(s, "# compressed entry header\n");
+ ret = trace_seq_printf(s, "\ttype_len : 5 bits\n");
+ ret = trace_seq_printf(s, "\ttime_delta : 27 bits\n");
+ ret = trace_seq_printf(s, "\tarray : 32 bits\n");
+ ret = trace_seq_printf(s, "\n");
+ ret = trace_seq_printf(s, "\tpadding : type == %d\n",
+ RINGBUF_TYPE_PADDING);
+ ret = trace_seq_printf(s, "\ttime_extend : type == %d\n",
+ RINGBUF_TYPE_TIME_EXTEND);
+ ret = trace_seq_printf(s, "\tdata max type_len == %d\n",
+ RINGBUF_TYPE_DATA_TYPE_LEN_MAX);
+
+ return ret;
+}
+
+/*
+ * The ring buffer is made up of a list of pages. A separate list of pages is
+ * allocated for each CPU. A writer may only write to a buffer that is
+ * associated with the CPU it is currently executing on. A reader may read
+ * from any per cpu buffer.
+ *
+ * The reader is special. For each per cpu buffer, the reader has its own
+ * reader page. When a reader has read the entire reader page, this reader
+ * page is swapped with another page in the ring buffer.
+ *
+ * Now, as long as the writer is off the reader page, the reader can do what
+ * ever it wants with that page. The writer will never write to that page
+ * again (as long as it is out of the ring buffer).
+ *
+ * Here's some silly ASCII art.
+ *
+ * +------+
+ * |reader| RING BUFFER
+ * |page |
+ * +------+ +---+ +---+ +---+
+ * | |-->| |-->| |
+ * +---+ +---+ +---+
+ * ^ |
+ * | |
+ * +---------------+
+ *
+ *
+ * +------+
+ * |reader| RING BUFFER
+ * |page |------------------v
+ * +------+ +---+ +---+ +---+
+ * | |-->| |-->| |
+ * +---+ +---+ +---+
+ * ^ |
+ * | |
+ * +---------------+
+ *
+ *
+ * +------+
+ * |reader| RING BUFFER
+ * |page |------------------v
+ * +------+ +---+ +---+ +---+
+ * ^ | |-->| |-->| |
+ * | +---+ +---+ +---+
+ * | |
+ * | |
+ * +------------------------------+
+ *
+ *
+ * +------+
+ * |buffer| RING BUFFER
+ * |page |------------------v
+ * +------+ +---+ +---+ +---+
+ * ^ | | | |-->| |
+ * | New +---+ +---+ +---+
+ * | Reader------^ |
+ * | page |
+ * +------------------------------+
+ *
+ *
+ * After we make this swap, the reader can hand this page off to the splice
+ * code and be done with it. It can even allocate a new page if it needs to
+ * and swap that into the ring buffer.
+ *
+ * We will be using cmpxchg soon to make all this lockless.
+ *
+ */
+
+/*
+ * A fast way to enable or disable all ring buffers is to
+ * call tracing_on or tracing_off. Turning off the ring buffers
+ * prevents all ring buffers from being recorded to.
+ * Turning this switch on, makes it OK to write to the
+ * ring buffer, if the ring buffer is enabled itself.
+ *
+ * There's three layers that must be on in order to write
+ * to the ring buffer.
+ *
+ * 1) This global flag must be set.
+ * 2) The ring buffer must be enabled for recording.
+ * 3) The per cpu buffer must be enabled for recording.
+ *
+ * In case of an anomaly, this global flag has a bit set that
+ * will permantly disable all ring buffers.
+ */
+
+/*
+ * Global flag to disable all recording to ring buffers
+ * This has two bits: ON, DISABLED
+ *
+ * ON DISABLED
+ * ---- ----------
+ * 0 0 : ring buffers are off
+ * 1 0 : ring buffers are on
+ * X 1 : ring buffers are permanently disabled
+ */
+
+enum {
+ RB_BUFFERS_ON_BIT = 0,
+ RB_BUFFERS_DISABLED_BIT = 1,
+};
+
+enum {
+ RB_BUFFERS_ON = 1 << RB_BUFFERS_ON_BIT,
+ RB_BUFFERS_DISABLED = 1 << RB_BUFFERS_DISABLED_BIT,
+};
+
+static unsigned long ftrace_ring_buffer_flags __read_mostly = RB_BUFFERS_ON;
+
+#define BUF_PAGE_HDR_SIZE offsetof(struct buffer_data_page, data)
+
+/**
+ * tracing_on - enable all tracing buffers
+ *
+ * This function enables all tracing buffers that may have been
+ * disabled with tracing_off.
+ */
+void tracing_on(void)
+{
+ set_bit(RB_BUFFERS_ON_BIT, &ftrace_ring_buffer_flags);
+}
+EXPORT_SYMBOL_GPL(tracing_on);
+
+/**
+ * tracing_off - turn off all tracing buffers
+ *
+ * This function stops all tracing buffers from recording data.
+ * It does not disable any overhead the tracers themselves may
+ * be causing. This function simply causes all recording to
+ * the ring buffers to fail.
+ */
+void tracing_off(void)
+{
+ clear_bit(RB_BUFFERS_ON_BIT, &ftrace_ring_buffer_flags);
+}
+EXPORT_SYMBOL_GPL(tracing_off);
+
+/**
+ * tracing_off_permanent - permanently disable ring buffers
+ *
+ * This function, once called, will disable all ring buffers
+ * permanently.
+ */
+void tracing_off_permanent(void)
+{
+ set_bit(RB_BUFFERS_DISABLED_BIT, &ftrace_ring_buffer_flags);
+}
+
+/**
+ * tracing_is_on - show state of ring buffers enabled
+ */
+int tracing_is_on(void)
+{
+ return ftrace_ring_buffer_flags == RB_BUFFERS_ON;
+}
+EXPORT_SYMBOL_GPL(tracing_is_on);
+
+#define RB_EVNT_HDR_SIZE (offsetof(struct ftrace_ring_buffer_event, array))
+#define RB_ALIGNMENT 4U
+#define RB_MAX_SMALL_DATA (RB_ALIGNMENT * RINGBUF_TYPE_DATA_TYPE_LEN_MAX)
+#define RB_EVNT_MIN_SIZE 8U /* two 32bit words */
+
+#if !defined(CONFIG_64BIT) || defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
+# define RB_FORCE_8BYTE_ALIGNMENT 0
+# define RB_ARCH_ALIGNMENT RB_ALIGNMENT
+#else
+# define RB_FORCE_8BYTE_ALIGNMENT 1
+# define RB_ARCH_ALIGNMENT 8U
+#endif
+
+/* define RINGBUF_TYPE_DATA for 'case RINGBUF_TYPE_DATA:' */
+#define RINGBUF_TYPE_DATA 0 ... RINGBUF_TYPE_DATA_TYPE_LEN_MAX
+
+enum {
+ RB_LEN_TIME_EXTEND = 8,
+ RB_LEN_TIME_STAMP = 16,
+};
+
+static inline int rb_null_event(struct ftrace_ring_buffer_event *event)
+{
+ return event->type_len == RINGBUF_TYPE_PADDING && !event->time_delta;
+}
+
+static void rb_event_set_padding(struct ftrace_ring_buffer_event *event)
+{
+ /* padding has a NULL time_delta */
+ event->type_len = RINGBUF_TYPE_PADDING;
+ event->time_delta = 0;
+}
+
+static unsigned
+rb_event_data_length(struct ftrace_ring_buffer_event *event)
+{
+ unsigned length;
+
+ if (event->type_len)
+ length = event->type_len * RB_ALIGNMENT;
+ else
+ length = event->array[0];
+ return length + RB_EVNT_HDR_SIZE;
+}
+
+/* inline for ring buffer fast paths */
+static unsigned
+rb_event_length(struct ftrace_ring_buffer_event *event)
+{
+ switch (event->type_len) {
+ case RINGBUF_TYPE_PADDING:
+ if (rb_null_event(event))
+ /* undefined */
+ return -1;
+ return event->array[0] + RB_EVNT_HDR_SIZE;
+
+ case RINGBUF_TYPE_TIME_EXTEND:
+ return RB_LEN_TIME_EXTEND;
+
+ case RINGBUF_TYPE_TIME_STAMP:
+ return RB_LEN_TIME_STAMP;
+
+ case RINGBUF_TYPE_DATA:
+ return rb_event_data_length(event);
+ default:
+ BUG();
+ }
+ /* not hit */
+ return 0;
+}
+
+/**
+ * ftrace_ring_buffer_event_length - return the length of the event
+ * @event: the event to get the length of
+ */
+unsigned ftrace_ring_buffer_event_length(struct ftrace_ring_buffer_event *event)
+{
+ unsigned length = rb_event_length(event);
+ if (event->type_len > RINGBUF_TYPE_DATA_TYPE_LEN_MAX)
+ return length;
+ length -= RB_EVNT_HDR_SIZE;
+ if (length > RB_MAX_SMALL_DATA + sizeof(event->array[0]))
+ length -= sizeof(event->array[0]);
+ return length;
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_event_length);
+
+/* inline for ring buffer fast paths */
+static void *
+rb_event_data(struct ftrace_ring_buffer_event *event)
+{
+ BUG_ON(event->type_len > RINGBUF_TYPE_DATA_TYPE_LEN_MAX);
+ /* If length is in len field, then array[0] has the data */
+ if (event->type_len)
+ return (void *)&event->array[0];
+ /* Otherwise length is in array[0] and array[1] has the data */
+ return (void *)&event->array[1];
+}
+
+/**
+ * ftrace_ring_buffer_event_data - return the data of the event
+ * @event: the event to get the data from
+ */
+void *ftrace_ring_buffer_event_data(struct ftrace_ring_buffer_event *event)
+{
+ return rb_event_data(event);
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_event_data);
+
+#define for_each_buffer_cpu(buffer, cpu) \
+ for_each_cpu(cpu, buffer->cpumask)
+
+#define TS_SHIFT 27
+#define TS_MASK ((1ULL << TS_SHIFT) - 1)
+#define TS_DELTA_TEST (~TS_MASK)
+
+/* Flag when events were overwritten */
+#define RB_MISSED_EVENTS (1 << 31)
+/* Missed count stored at end */
+#define RB_MISSED_STORED (1 << 30)
+
+struct buffer_data_page {
+ u64 time_stamp; /* page time stamp */
+ local_t commit; /* write committed index */
+ unsigned char data[]; /* data of buffer page */
+};
+
+/*
+ * Note, the buffer_page list must be first. The buffer pages
+ * are allocated in cache lines, which means that each buffer
+ * page will be at the beginning of a cache line, and thus
+ * the least significant bits will be zero. We use this to
+ * add flags in the list struct pointers, to make the ring buffer
+ * lockless.
+ */
+struct buffer_page {
+ struct list_head list; /* list of buffer pages */
+ local_t write; /* index for next write */
+ unsigned read; /* index for next read */
+ local_t entries; /* entries on this page */
+ unsigned long real_end; /* real end of data */
+ struct buffer_data_page *page; /* Actual data page */
+};
+
+/*
+ * The buffer page counters, write and entries, must be reset
+ * atomically when crossing page boundaries. To synchronize this
+ * update, two counters are inserted into the number. One is
+ * the actual counter for the write position or count on the page.
+ *
+ * The other is a counter of updaters. Before an update happens
+ * the update partition of the counter is incremented. This will
+ * allow the updater to update the counter atomically.
+ *
+ * The counter is 20 bits, and the state data is 12.
+ */
+#define RB_WRITE_MASK 0xfffff
+#define RB_WRITE_INTCNT (1 << 20)
+
+static void rb_init_page(struct buffer_data_page *bpage)
+{
+ local_set(&bpage->commit, 0);
+}
+
+/**
+ * ftrace_ring_buffer_page_len - the size of data on the page.
+ * @page: The page to read
+ *
+ * Returns the amount of data on the page, including buffer page header.
+ */
+size_t ftrace_ring_buffer_page_len(void *page)
+{
+ return local_read(&((struct buffer_data_page *)page)->commit)
+ + BUF_PAGE_HDR_SIZE;
+}
+
+/*
+ * Also stolen from mm/slob.c. Thanks to Mathieu Desnoyers for pointing
+ * this issue out.
+ */
+static void free_buffer_page(struct buffer_page *bpage)
+{
+ free_page((unsigned long)bpage->page);
+ kfree(bpage);
+}
+
+/*
+ * We need to fit the time_stamp delta into 27 bits.
+ */
+static inline int test_time_stamp(u64 delta)
+{
+ if (delta & TS_DELTA_TEST)
+ return 1;
+ return 0;
+}
+
+#define BUF_PAGE_SIZE (PAGE_SIZE - BUF_PAGE_HDR_SIZE)
+
+/* Max payload is BUF_PAGE_SIZE - header (8bytes) */
+#define BUF_MAX_DATA_SIZE (BUF_PAGE_SIZE - (sizeof(u32) * 2))
+
+/* Max number of timestamps that can fit on a page */
+#define RB_TIMESTAMPS_PER_PAGE (BUF_PAGE_SIZE / RB_LEN_TIME_STAMP)
+
+int ftrace_ring_buffer_print_page_header(struct trace_seq *s)
+{
+ struct buffer_data_page field;
+ int ret;
+
+ ret = trace_seq_printf(s, "\tfield: u64 timestamp;\t"
+ "offset:0;\tsize:%u;\tsigned:%u;\n",
+ (unsigned int)sizeof(field.time_stamp),
+ (unsigned int)is_signed_type(u64));
+
+ ret = trace_seq_printf(s, "\tfield: local_t commit;\t"
+ "offset:%u;\tsize:%u;\tsigned:%u;\n",
+ (unsigned int)offsetof(typeof(field), commit),
+ (unsigned int)sizeof(field.commit),
+ (unsigned int)is_signed_type(long));
+
+ ret = trace_seq_printf(s, "\tfield: int overwrite;\t"
+ "offset:%u;\tsize:%u;\tsigned:%u;\n",
+ (unsigned int)offsetof(typeof(field), commit),
+ 1,
+ (unsigned int)is_signed_type(long));
+
+ ret = trace_seq_printf(s, "\tfield: char data;\t"
+ "offset:%u;\tsize:%u;\tsigned:%u;\n",
+ (unsigned int)offsetof(typeof(field), data),
+ (unsigned int)BUF_PAGE_SIZE,
+ (unsigned int)is_signed_type(char));
+
+ return ret;
+}
+
+/*
+ * head_page == tail_page && head == tail then buffer is empty.
+ */
+struct ftrace_ring_buffer_per_cpu {
+ int cpu;
+ struct ftrace_ring_buffer *buffer;
+ spinlock_t reader_lock; /* serialize readers */
+ arch_spinlock_t lock;
+ struct lock_class_key lock_key;
+ struct list_head *pages;
+ struct buffer_page *head_page; /* read from head */
+ struct buffer_page *tail_page; /* write to tail */
+ struct buffer_page *commit_page; /* committed pages */
+ struct buffer_page *reader_page;
+ unsigned long lost_events;
+ unsigned long last_overrun;
+ local_t commit_overrun;
+ local_t overrun;
+ local_t entries;
+ local_t committing;
+ local_t commits;
+ unsigned long read;
+ u64 write_stamp;
+ u64 read_stamp;
+ atomic_t record_disabled;
+};
+
+struct ftrace_ring_buffer {
+ unsigned pages;
+ unsigned flags;
+ int cpus;
+ atomic_t record_disabled;
+ cpumask_var_t cpumask;
+
+ struct lock_class_key *reader_lock_key;
+
+ struct mutex mutex;
+
+ struct ftrace_ring_buffer_per_cpu **buffers;
+
+#ifdef CONFIG_HOTPLUG_CPU
+ struct notifier_block cpu_notify;
+#endif
+ u64 (*clock)(void);
+};
+
+struct ftrace_ring_buffer_iter {
+ struct ftrace_ring_buffer_per_cpu *cpu_buffer;
+ unsigned long head;
+ struct buffer_page *head_page;
+ struct buffer_page *cache_reader_page;
+ unsigned long cache_read;
+ u64 read_stamp;
+};
+
+/* buffer may be either ftrace_ring_buffer or ftrace_ring_buffer_per_cpu */
+#define RB_WARN_ON(b, cond) \
+ ({ \
+ int _____ret = unlikely(cond); \
+ if (_____ret) { \
+ if (__same_type(*(b), struct ftrace_ring_buffer_per_cpu)) { \
+ struct ftrace_ring_buffer_per_cpu *__b = \
+ (void *)b; \
+ atomic_inc(&__b->buffer->record_disabled); \
+ } else \
+ atomic_inc(&b->record_disabled); \
+ WARN_ON(1); \
+ } \
+ _____ret; \
+ })
+
+/* Up this if you want to test the TIME_EXTENTS and normalization */
+#define DEBUG_SHIFT 0
+
+static inline u64 rb_time_stamp(struct ftrace_ring_buffer *buffer)
+{
+ /* shift to debug/test normalization and TIME_EXTENTS */
+ return buffer->clock() << DEBUG_SHIFT;
+}
+
+u64 ftrace_ring_buffer_time_stamp(struct ftrace_ring_buffer *buffer, int cpu)
+{
+ u64 time;
+
+ preempt_disable_notrace();
+ time = rb_time_stamp(buffer);
+ preempt_enable_no_resched_notrace();
+
+ return time;
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_time_stamp);
+
+void ftrace_ring_buffer_normalize_time_stamp(struct ftrace_ring_buffer *buffer,
+ int cpu, u64 *ts)
+{
+ /* Just stupid testing the normalize function and deltas */
+ *ts >>= DEBUG_SHIFT;
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_normalize_time_stamp);
+
+/*
+ * Making the ring buffer lockless makes things tricky.
+ * Although writes only happen on the CPU that they are on,
+ * and they only need to worry about interrupts. Reads can
+ * happen on any CPU.
+ *
+ * The reader page is always off the ring buffer, but when the
+ * reader finishes with a page, it needs to swap its page with
+ * a new one from the buffer. The reader needs to take from
+ * the head (writes go to the tail). But if a writer is in overwrite
+ * mode and wraps, it must push the head page forward.
+ *
+ * Here lies the problem.
+ *
+ * The reader must be careful to replace only the head page, and
+ * not another one. As described at the top of the file in the
+ * ASCII art, the reader sets its old page to point to the next
+ * page after head. It then sets the page after head to point to
+ * the old reader page. But if the writer moves the head page
+ * during this operation, the reader could end up with the tail.
+ *
+ * We use cmpxchg to help prevent this race. We also do something
+ * special with the page before head. We set the LSB to 1.
+ *
+ * When the writer must push the page forward, it will clear the
+ * bit that points to the head page, move the head, and then set
+ * the bit that points to the new head page.
+ *
+ * We also don't want an interrupt coming in and moving the head
+ * page on another writer. Thus we use the second LSB to catch
+ * that too. Thus:
+ *
+ * head->list->prev->next bit 1 bit 0
+ * ------- -------
+ * Normal page 0 0
+ * Points to head page 0 1
+ * New head page 1 0
+ *
+ * Note we can not trust the prev pointer of the head page, because:
+ *
+ * +----+ +-----+ +-----+
+ * | |------>| T |---X--->| N |
+ * | |<------| | | |
+ * +----+ +-----+ +-----+
+ * ^ ^ |
+ * | +-----+ | |
+ * +----------| R |----------+ |
+ * | |<-----------+
+ * +-----+
+ *
+ * Key: ---X--> HEAD flag set in pointer
+ * T Tail page
+ * R Reader page
+ * N Next page
+ *
+ * (see __rb_reserve_next() to see where this happens)
+ *
+ * What the above shows is that the reader just swapped out
+ * the reader page with a page in the buffer, but before it
+ * could make the new header point back to the new page added
+ * it was preempted by a writer. The writer moved forward onto
+ * the new page added by the reader and is about to move forward
+ * again.
+ *
+ * You can see, it is legitimate for the previous pointer of
+ * the head (or any page) not to point back to itself. But only
+ * temporarially.
+ */
+
+#define RB_PAGE_NORMAL 0UL
+#define RB_PAGE_HEAD 1UL
+#define RB_PAGE_UPDATE 2UL
+
+
+#define RB_FLAG_MASK 3UL
+
+/* PAGE_MOVED is not part of the mask */
+#define RB_PAGE_MOVED 4UL
+
+/*
+ * rb_list_head - remove any bit
+ */
+static struct list_head *rb_list_head(struct list_head *list)
+{
+ unsigned long val = (unsigned long)list;
+
+ return (struct list_head *)(val & ~RB_FLAG_MASK);
+}
+
+/*
+ * rb_is_head_page - test if the given page is the head page
+ *
+ * Because the reader may move the head_page pointer, we can
+ * not trust what the head page is (it may be pointing to
+ * the reader page). But if the next page is a header page,
+ * its flags will be non zero.
+ */
+static int inline
+rb_is_head_page(struct ftrace_ring_buffer_per_cpu *cpu_buffer,
+ struct buffer_page *page, struct list_head *list)
+{
+ unsigned long val;
+
+ val = (unsigned long)list->next;
+
+ if ((val & ~RB_FLAG_MASK) != (unsigned long)&page->list)
+ return RB_PAGE_MOVED;
+
+ return val & RB_FLAG_MASK;
+}
+
+/*
+ * rb_is_reader_page
+ *
+ * The unique thing about the reader page, is that, if the
+ * writer is ever on it, the previous pointer never points
+ * back to the reader page.
+ */
+static int rb_is_reader_page(struct buffer_page *page)
+{
+ struct list_head *list = page->list.prev;
+
+ return rb_list_head(list->next) != &page->list;
+}
+
+/*
+ * rb_set_list_to_head - set a list_head to be pointing to head.
+ */
+static void rb_set_list_to_head(struct ftrace_ring_buffer_per_cpu *cpu_buffer,
+ struct list_head *list)
+{
+ unsigned long *ptr;
+
+ ptr = (unsigned long *)&list->next;
+ *ptr |= RB_PAGE_HEAD;
+ *ptr &= ~RB_PAGE_UPDATE;
+}
+
+/*
+ * rb_head_page_activate - sets up head page
+ */
+static void rb_head_page_activate(struct ftrace_ring_buffer_per_cpu *cpu_buffer)
+{
+ struct buffer_page *head;
+
+ head = cpu_buffer->head_page;
+ if (!head)
+ return;
+
+ /*
+ * Set the previous list pointer to have the HEAD flag.
+ */
+ rb_set_list_to_head(cpu_buffer, head->list.prev);
+}
+
+static void rb_list_head_clear(struct list_head *list)
+{
+ unsigned long *ptr = (unsigned long *)&list->next;
+
+ *ptr &= ~RB_FLAG_MASK;
+}
+
+/*
+ * rb_head_page_dactivate - clears head page ptr (for free list)
+ */
+static void
+rb_head_page_deactivate(struct ftrace_ring_buffer_per_cpu *cpu_buffer)
+{
+ struct list_head *hd;
+
+ /* Go through the whole list and clear any pointers found. */
+ rb_list_head_clear(cpu_buffer->pages);
+
+ list_for_each(hd, cpu_buffer->pages)
+ rb_list_head_clear(hd);
+}
+
+static int rb_head_page_set(struct ftrace_ring_buffer_per_cpu *cpu_buffer,
+ struct buffer_page *head,
+ struct buffer_page *prev,
+ int old_flag, int new_flag)
+{
+ struct list_head *list;
+ unsigned long val = (unsigned long)&head->list;
+ unsigned long ret;
+
+ list = &prev->list;
+
+ val &= ~RB_FLAG_MASK;
+
+ ret = cmpxchg((unsigned long *)&list->next,
+ val | old_flag, val | new_flag);
+
+ /* check if the reader took the page */
+ if ((ret & ~RB_FLAG_MASK) != val)
+ return RB_PAGE_MOVED;
+
+ return ret & RB_FLAG_MASK;
+}
+
+static int rb_head_page_set_update(struct ftrace_ring_buffer_per_cpu *cpu_buffer,
+ struct buffer_page *head,
+ struct buffer_page *prev,
+ int old_flag)
+{
+ return rb_head_page_set(cpu_buffer, head, prev,
+ old_flag, RB_PAGE_UPDATE);
+}
+
+static int rb_head_page_set_head(struct ftrace_ring_buffer_per_cpu *cpu_buffer,
+ struct buffer_page *head,
+ struct buffer_page *prev,
+ int old_flag)
+{
+ return rb_head_page_set(cpu_buffer, head, prev,
+ old_flag, RB_PAGE_HEAD);
+}
+
+static int rb_head_page_set_normal(struct ftrace_ring_buffer_per_cpu *cpu_buffer,
+ struct buffer_page *head,
+ struct buffer_page *prev,
+ int old_flag)
+{
+ return rb_head_page_set(cpu_buffer, head, prev,
+ old_flag, RB_PAGE_NORMAL);
+}
+
+static inline void rb_inc_page(struct ftrace_ring_buffer_per_cpu *cpu_buffer,
+ struct buffer_page **bpage)
+{
+ struct list_head *p = rb_list_head((*bpage)->list.next);
+
+ *bpage = list_entry(p, struct buffer_page, list);
+}
+
+static struct buffer_page *
+rb_set_head_page(struct ftrace_ring_buffer_per_cpu *cpu_buffer)
+{
+ struct buffer_page *head;
+ struct buffer_page *page;
+ struct list_head *list;
+ int i;
+
+ if (RB_WARN_ON(cpu_buffer, !cpu_buffer->head_page))
+ return NULL;
+
+ /* sanity check */
+ list = cpu_buffer->pages;
+ if (RB_WARN_ON(cpu_buffer, rb_list_head(list->prev->next) != list))
+ return NULL;
+
+ page = head = cpu_buffer->head_page;
+ /*
+ * It is possible that the writer moves the header behind
+ * where we started, and we miss in one loop.
+ * A second loop should grab the header, but we'll do
+ * three loops just because I'm paranoid.
+ */
+ for (i = 0; i < 3; i++) {
+ do {
+ if (rb_is_head_page(cpu_buffer, page, page->list.prev)) {
+ cpu_buffer->head_page = page;
+ return page;
+ }
+ rb_inc_page(cpu_buffer, &page);
+ } while (page != head);
+ }
+
+ RB_WARN_ON(cpu_buffer, 1);
+
+ return NULL;
+}
+
+static int rb_head_page_replace(struct buffer_page *old,
+ struct buffer_page *new)
+{
+ unsigned long *ptr = (unsigned long *)&old->list.prev->next;
+ unsigned long val;
+ unsigned long ret;
+
+ val = *ptr & ~RB_FLAG_MASK;
+ val |= RB_PAGE_HEAD;
+
+ ret = cmpxchg(ptr, val, (unsigned long)&new->list);
+
+ return ret == val;
+}
+
+/*
+ * rb_tail_page_update - move the tail page forward
+ *
+ * Returns 1 if moved tail page, 0 if someone else did.
+ */
+static int rb_tail_page_update(struct ftrace_ring_buffer_per_cpu *cpu_buffer,
+ struct buffer_page *tail_page,
+ struct buffer_page *next_page)
+{
+ struct buffer_page *old_tail;
+ unsigned long old_entries;
+ unsigned long old_write;
+ int ret = 0;
+
+ /*
+ * The tail page now needs to be moved forward.
+ *
+ * We need to reset the tail page, but without messing
+ * with possible erasing of data brought in by interrupts
+ * that have moved the tail page and are currently on it.
+ *
+ * We add a counter to the write field to denote this.
+ */
+ old_write = local_add_return(RB_WRITE_INTCNT, &next_page->write);
+ old_entries = local_add_return(RB_WRITE_INTCNT, &next_page->entries);
+
+ /*
+ * Just make sure we have seen our old_write and synchronize
+ * with any interrupts that come in.
+ */
+ barrier();
+
+ /*
+ * If the tail page is still the same as what we think
+ * it is, then it is up to us to update the tail
+ * pointer.
+ */
+ if (tail_page == cpu_buffer->tail_page) {
+ /* Zero the write counter */
+ unsigned long val = old_write & ~RB_WRITE_MASK;
+ unsigned long eval = old_entries & ~RB_WRITE_MASK;
+
+ /*
+ * This will only succeed if an interrupt did
+ * not come in and change it. In which case, we
+ * do not want to modify it.
+ *
+ * We add (void) to let the compiler know that we do not care
+ * about the return value of these functions. We use the
+ * cmpxchg to only update if an interrupt did not already
+ * do it for us. If the cmpxchg fails, we don't care.
+ */
+ (void)local_cmpxchg(&next_page->write, old_write, val);
+ (void)local_cmpxchg(&next_page->entries, old_entries, eval);
+
+ /*
+ * No need to worry about races with clearing out the commit.
+ * it only can increment when a commit takes place. But that
+ * only happens in the outer most nested commit.
+ */
+ local_set(&next_page->page->commit, 0);
+
+ old_tail = cmpxchg(&cpu_buffer->tail_page,
+ tail_page, next_page);
+
+ if (old_tail == tail_page)
+ ret = 1;
+ }
+
+ return ret;
+}
+
+static int rb_check_bpage(struct ftrace_ring_buffer_per_cpu *cpu_buffer,
+ struct buffer_page *bpage)
+{
+ unsigned long val = (unsigned long)bpage;
+
+ if (RB_WARN_ON(cpu_buffer, val & RB_FLAG_MASK))
+ return 1;
+
+ return 0;
+}
+
+/**
+ * rb_check_list - make sure a pointer to a list has the last bits zero
+ */
+static int rb_check_list(struct ftrace_ring_buffer_per_cpu *cpu_buffer,
+ struct list_head *list)
+{
+ if (RB_WARN_ON(cpu_buffer, rb_list_head(list->prev) != list->prev))
+ return 1;
+ if (RB_WARN_ON(cpu_buffer, rb_list_head(list->next) != list->next))
+ return 1;
+ return 0;
+}
+
+/**
+ * check_pages - integrity check of buffer pages
+ * @cpu_buffer: CPU buffer with pages to test
+ *
+ * As a safety measure we check to make sure the data pages have not
+ * been corrupted.
+ */
+static int rb_check_pages(struct ftrace_ring_buffer_per_cpu *cpu_buffer)
+{
+ struct list_head *head = cpu_buffer->pages;
+ struct buffer_page *bpage, *tmp;
+
+ rb_head_page_deactivate(cpu_buffer);
+
+ if (RB_WARN_ON(cpu_buffer, head->next->prev != head))
+ return -1;
+ if (RB_WARN_ON(cpu_buffer, head->prev->next != head))
+ return -1;
+
+ if (rb_check_list(cpu_buffer, head))
+ return -1;
+
+ list_for_each_entry_safe(bpage, tmp, head, list) {
+ if (RB_WARN_ON(cpu_buffer,
+ bpage->list.next->prev != &bpage->list))
+ return -1;
+ if (RB_WARN_ON(cpu_buffer,
+ bpage->list.prev->next != &bpage->list))
+ return -1;
+ if (rb_check_list(cpu_buffer, &bpage->list))
+ return -1;
+ }
+
+ rb_head_page_activate(cpu_buffer);
+
+ return 0;
+}
+
+static int rb_allocate_pages(struct ftrace_ring_buffer_per_cpu *cpu_buffer,
+ unsigned nr_pages)
+{
+ struct buffer_page *bpage, *tmp;
+ unsigned long addr;
+ LIST_HEAD(pages);
+ unsigned i;
+
+ WARN_ON(!nr_pages);
+
+ for (i = 0; i < nr_pages; i++) {
+ bpage = kzalloc_node(ALIGN(sizeof(*bpage), cache_line_size()),
+ GFP_KERNEL, cpu_to_node(cpu_buffer->cpu));
+ if (!bpage)
+ goto free_pages;
+
+ rb_check_bpage(cpu_buffer, bpage);
+
+ list_add(&bpage->list, &pages);
+
+ addr = __get_free_page(GFP_KERNEL);
+ if (!addr)
+ goto free_pages;
+ bpage->page = (void *)addr;
+ rb_init_page(bpage->page);
+ }
+
+ /*
+ * The ring buffer page list is a circular list that does not
+ * start and end with a list head. All page list items point to
+ * other pages.
+ */
+ cpu_buffer->pages = pages.next;
+ list_del(&pages);
+
+ rb_check_pages(cpu_buffer);
+
+ return 0;
+
+ free_pages:
+ list_for_each_entry_safe(bpage, tmp, &pages, list) {
+ list_del_init(&bpage->list);
+ free_buffer_page(bpage);
+ }
+ return -ENOMEM;
+}
+
+static struct ftrace_ring_buffer_per_cpu *
+rb_allocate_cpu_buffer(struct ftrace_ring_buffer *buffer, int cpu)
+{
+ struct ftrace_ring_buffer_per_cpu *cpu_buffer;
+ struct buffer_page *bpage;
+ unsigned long addr;
+ int ret;
+
+ cpu_buffer = kzalloc_node(ALIGN(sizeof(*cpu_buffer), cache_line_size()),
+ GFP_KERNEL, cpu_to_node(cpu));
+ if (!cpu_buffer)
+ return NULL;
+
+ cpu_buffer->cpu = cpu;
+ cpu_buffer->buffer = buffer;
+ spin_lock_init(&cpu_buffer->reader_lock);
+ lockdep_set_class(&cpu_buffer->reader_lock, buffer->reader_lock_key);
+ cpu_buffer->lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
+
+ bpage = kzalloc_node(ALIGN(sizeof(*bpage), cache_line_size()),
+ GFP_KERNEL, cpu_to_node(cpu));
+ if (!bpage)
+ goto fail_free_buffer;
+
+ rb_check_bpage(cpu_buffer, bpage);
+
+ cpu_buffer->reader_page = bpage;
+ addr = __get_free_page(GFP_KERNEL);
+ if (!addr)
+ goto fail_free_reader;
+ bpage->page = (void *)addr;
+ rb_init_page(bpage->page);
+
+ INIT_LIST_HEAD(&cpu_buffer->reader_page->list);
+
+ ret = rb_allocate_pages(cpu_buffer, buffer->pages);
+ if (ret < 0)
+ goto fail_free_reader;
+
+ cpu_buffer->head_page
+ = list_entry(cpu_buffer->pages, struct buffer_page, list);
+ cpu_buffer->tail_page = cpu_buffer->commit_page = cpu_buffer->head_page;
+
+ rb_head_page_activate(cpu_buffer);
+
+ return cpu_buffer;
+
+ fail_free_reader:
+ free_buffer_page(cpu_buffer->reader_page);
+
+ fail_free_buffer:
+ kfree(cpu_buffer);
+ return NULL;
+}
+
+static void rb_free_cpu_buffer(struct ftrace_ring_buffer_per_cpu *cpu_buffer)
+{
+ struct list_head *head = cpu_buffer->pages;
+ struct buffer_page *bpage, *tmp;
+
+ free_buffer_page(cpu_buffer->reader_page);
+
+ rb_head_page_deactivate(cpu_buffer);
+
+ if (head) {
+ list_for_each_entry_safe(bpage, tmp, head, list) {
+ list_del_init(&bpage->list);
+ free_buffer_page(bpage);
+ }
+ bpage = list_entry(head, struct buffer_page, list);
+ free_buffer_page(bpage);
+ }
+
+ kfree(cpu_buffer);
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+static int rb_cpu_notify(struct notifier_block *self,
+ unsigned long action, void *hcpu);
+#endif
+
+/**
+ * ftrace_ring_buffer_alloc - allocate a new ftrace_ring_buffer
+ * @size: the size in bytes per cpu that is needed.
+ * @flags: attributes to set for the ring buffer.
+ *
+ * Currently the only flag that is available is the RB_FL_OVERWRITE
+ * flag. This flag means that the buffer will overwrite old data
+ * when the buffer wraps. If this flag is not set, the buffer will
+ * drop data when the tail hits the head.
+ */
+struct ftrace_ring_buffer *__ftrace_ring_buffer_alloc(unsigned long size, unsigned flags,
+ struct lock_class_key *key)
+{
+ struct ftrace_ring_buffer *buffer;
+ int bsize;
+ int cpu;
+
+ /* keep it in its own cache line */
+ buffer = kzalloc(ALIGN(sizeof(*buffer), cache_line_size()),
+ GFP_KERNEL);
+ if (!buffer)
+ return NULL;
+
+ if (!alloc_cpumask_var(&buffer->cpumask, GFP_KERNEL))
+ goto fail_free_buffer;
+
+ buffer->pages = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
+ buffer->flags = flags;
+ buffer->clock = trace_clock_local;
+ buffer->reader_lock_key = key;
+
+ /* need at least two pages */
+ if (buffer->pages < 2)
+ buffer->pages = 2;
+
+ /*
+ * In case of non-hotplug cpu, if the ring-buffer is allocated
+ * in early initcall, it will not be notified of secondary cpus.
+ * In that off case, we need to allocate for all possible cpus.
+ */
+#ifdef CONFIG_HOTPLUG_CPU
+ get_online_cpus();
+ cpumask_copy(buffer->cpumask, cpu_online_mask);
+#else
+ cpumask_copy(buffer->cpumask, cpu_possible_mask);
+#endif
+ buffer->cpus = nr_cpu_ids;
+
+ bsize = sizeof(void *) * nr_cpu_ids;
+ buffer->buffers = kzalloc(ALIGN(bsize, cache_line_size()),
+ GFP_KERNEL);
+ if (!buffer->buffers)
+ goto fail_free_cpumask;
+
+ for_each_buffer_cpu(buffer, cpu) {
+ buffer->buffers[cpu] =
+ rb_allocate_cpu_buffer(buffer, cpu);
+ if (!buffer->buffers[cpu])
+ goto fail_free_buffers;
+ }
+
+#ifdef CONFIG_HOTPLUG_CPU
+ buffer->cpu_notify.notifier_call = rb_cpu_notify;
+ buffer->cpu_notify.priority = 0;
+ register_cpu_notifier(&buffer->cpu_notify);
+#endif
+
+ put_online_cpus();
+ mutex_init(&buffer->mutex);
+
+ return buffer;
+
+ fail_free_buffers:
+ for_each_buffer_cpu(buffer, cpu) {
+ if (buffer->buffers[cpu])
+ rb_free_cpu_buffer(buffer->buffers[cpu]);
+ }
+ kfree(buffer->buffers);
+
+ fail_free_cpumask:
+ free_cpumask_var(buffer->cpumask);
+ put_online_cpus();
+
+ fail_free_buffer:
+ kfree(buffer);
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(__ftrace_ring_buffer_alloc);
+
+/**
+ * ftrace_ring_buffer_free - free a ring buffer.
+ * @buffer: the buffer to free.
+ */
+void
+ftrace_ring_buffer_free(struct ftrace_ring_buffer *buffer)
+{
+ int cpu;
+
+ get_online_cpus();
+
+#ifdef CONFIG_HOTPLUG_CPU
+ unregister_cpu_notifier(&buffer->cpu_notify);
+#endif
+
+ for_each_buffer_cpu(buffer, cpu)
+ rb_free_cpu_buffer(buffer->buffers[cpu]);
+
+ put_online_cpus();
+
+ kfree(buffer->buffers);
+ free_cpumask_var(buffer->cpumask);
+
+ kfree(buffer);
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_free);
+
+void ftrace_ring_buffer_set_clock(struct ftrace_ring_buffer *buffer,
+ u64 (*clock)(void))
+{
+ buffer->clock = clock;
+}
+
+static void rb_reset_cpu(struct ftrace_ring_buffer_per_cpu *cpu_buffer);
+
+static void
+rb_remove_pages(struct ftrace_ring_buffer_per_cpu *cpu_buffer, unsigned nr_pages)
+{
+ struct buffer_page *bpage;
+ struct list_head *p;
+ unsigned i;
+
+ spin_lock_irq(&cpu_buffer->reader_lock);
+ rb_head_page_deactivate(cpu_buffer);
+
+ for (i = 0; i < nr_pages; i++) {
+ if (RB_WARN_ON(cpu_buffer, list_empty(cpu_buffer->pages)))
+ goto out;
+ p = cpu_buffer->pages->next;
+ bpage = list_entry(p, struct buffer_page, list);
+ list_del_init(&bpage->list);
+ free_buffer_page(bpage);
+ }
+ if (RB_WARN_ON(cpu_buffer, list_empty(cpu_buffer->pages)))
+ goto out;
+
+ rb_reset_cpu(cpu_buffer);
+ rb_check_pages(cpu_buffer);
+
+out:
+ spin_unlock_irq(&cpu_buffer->reader_lock);
+}
+
+static void
+rb_insert_pages(struct ftrace_ring_buffer_per_cpu *cpu_buffer,
+ struct list_head *pages, unsigned nr_pages)
+{
+ struct buffer_page *bpage;
+ struct list_head *p;
+ unsigned i;
+
+ spin_lock_irq(&cpu_buffer->reader_lock);
+ rb_head_page_deactivate(cpu_buffer);
+
+ for (i = 0; i < nr_pages; i++) {
+ if (RB_WARN_ON(cpu_buffer, list_empty(pages)))
+ goto out;
+ p = pages->next;
+ bpage = list_entry(p, struct buffer_page, list);
+ list_del_init(&bpage->list);
+ list_add_tail(&bpage->list, cpu_buffer->pages);
+ }
+ rb_reset_cpu(cpu_buffer);
+ rb_check_pages(cpu_buffer);
+
+out:
+ spin_unlock_irq(&cpu_buffer->reader_lock);
+}
+
+/**
+ * ftrace_ring_buffer_resize - resize the ring buffer
+ * @buffer: the buffer to resize.
+ * @size: the new size.
+ *
+ * Minimum size is 2 * BUF_PAGE_SIZE.
+ *
+ * Returns -1 on failure.
+ */
+int ftrace_ring_buffer_resize(struct ftrace_ring_buffer *buffer, unsigned long size)
+{
+ struct ftrace_ring_buffer_per_cpu *cpu_buffer;
+ unsigned nr_pages, rm_pages, new_pages;
+ struct buffer_page *bpage, *tmp;
+ unsigned long buffer_size;
+ unsigned long addr;
+ LIST_HEAD(pages);
+ int i, cpu;
+
+ /*
+ * Always succeed at resizing a non-existent buffer:
+ */
+ if (!buffer)
+ return size;
+
+ size = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
+ size *= BUF_PAGE_SIZE;
+ buffer_size = buffer->pages * BUF_PAGE_SIZE;
+
+ /* we need a minimum of two pages */
+ if (size < BUF_PAGE_SIZE * 2)
+ size = BUF_PAGE_SIZE * 2;
+
+ if (size == buffer_size)
+ return size;
+
+ atomic_inc(&buffer->record_disabled);
+
+ /* Make sure all writers are done with this buffer. */
+ synchronize_sched();
+
+ mutex_lock(&buffer->mutex);
+ get_online_cpus();
+
+ nr_pages = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
+
+ if (size < buffer_size) {
+
+ /* easy case, just free pages */
+ if (RB_WARN_ON(buffer, nr_pages >= buffer->pages))
+ goto out_fail;
+
+ rm_pages = buffer->pages - nr_pages;
+
+ for_each_buffer_cpu(buffer, cpu) {
+ cpu_buffer = buffer->buffers[cpu];
+ rb_remove_pages(cpu_buffer, rm_pages);
+ }
+ goto out;
+ }
+
+ /*
+ * This is a bit more difficult. We only want to add pages
+ * when we can allocate enough for all CPUs. We do this
+ * by allocating all the pages and storing them on a local
+ * link list. If we succeed in our allocation, then we
+ * add these pages to the cpu_buffers. Otherwise we just free
+ * them all and return -ENOMEM;
+ */
+ if (RB_WARN_ON(buffer, nr_pages <= buffer->pages))
+ goto out_fail;
+
+ new_pages = nr_pages - buffer->pages;
+
+ for_each_buffer_cpu(buffer, cpu) {
+ for (i = 0; i < new_pages; i++) {
+ bpage = kzalloc_node(ALIGN(sizeof(*bpage),
+ cache_line_size()),
+ GFP_KERNEL, cpu_to_node(cpu));
+ if (!bpage)
+ goto free_pages;
+ list_add(&bpage->list, &pages);
+ addr = __get_free_page(GFP_KERNEL);
+ if (!addr)
+ goto free_pages;
+ bpage->page = (void *)addr;
+ rb_init_page(bpage->page);
+ }
+ }
+
+ for_each_buffer_cpu(buffer, cpu) {
+ cpu_buffer = buffer->buffers[cpu];
+ rb_insert_pages(cpu_buffer, &pages, new_pages);
+ }
+
+ if (RB_WARN_ON(buffer, !list_empty(&pages)))
+ goto out_fail;
+
+ out:
+ buffer->pages = nr_pages;
+ put_online_cpus();
+ mutex_unlock(&buffer->mutex);
+
+ atomic_dec(&buffer->record_disabled);
+
+ return size;
+
+ free_pages:
+ list_for_each_entry_safe(bpage, tmp, &pages, list) {
+ list_del_init(&bpage->list);
+ free_buffer_page(bpage);
+ }
+ put_online_cpus();
+ mutex_unlock(&buffer->mutex);
+ atomic_dec(&buffer->record_disabled);
+ return -ENOMEM;
+
+ /*
+ * Something went totally wrong, and we are too paranoid
+ * to even clean up the mess.
+ */
+ out_fail:
+ put_online_cpus();
+ mutex_unlock(&buffer->mutex);
+ atomic_dec(&buffer->record_disabled);
+ return -1;
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_resize);
+
+static inline void *
+__rb_data_page_index(struct buffer_data_page *bpage, unsigned index)
+{
+ return bpage->data + index;
+}
+
+static inline void *__rb_page_index(struct buffer_page *bpage, unsigned index)
+{
+ return bpage->page->data + index;
+}
+
+static inline struct ftrace_ring_buffer_event *
+rb_reader_event(struct ftrace_ring_buffer_per_cpu *cpu_buffer)
+{
+ return __rb_page_index(cpu_buffer->reader_page,
+ cpu_buffer->reader_page->read);
+}
+
+static inline struct ftrace_ring_buffer_event *
+rb_iter_head_event(struct ftrace_ring_buffer_iter *iter)
+{
+ return __rb_page_index(iter->head_page, iter->head);
+}
+
+static inline unsigned long rb_page_write(struct buffer_page *bpage)
+{
+ return local_read(&bpage->write) & RB_WRITE_MASK;
+}
+
+static inline unsigned rb_page_commit(struct buffer_page *bpage)
+{
+ return local_read(&bpage->page->commit);
+}
+
+static inline unsigned long rb_page_entries(struct buffer_page *bpage)
+{
+ return local_read(&bpage->entries) & RB_WRITE_MASK;
+}
+
+/* Size is determined by what has been commited */
+static inline unsigned rb_page_size(struct buffer_page *bpage)
+{
+ return rb_page_commit(bpage);
+}
+
+static inline unsigned
+rb_commit_index(struct ftrace_ring_buffer_per_cpu *cpu_buffer)
+{
+ return rb_page_commit(cpu_buffer->commit_page);
+}
+
+static inline unsigned
+rb_event_index(struct ftrace_ring_buffer_event *event)
+{
+ unsigned long addr = (unsigned long)event;
+
+ return (addr & ~PAGE_MASK) - BUF_PAGE_HDR_SIZE;
+}
+
+static inline int
+rb_event_is_commit(struct ftrace_ring_buffer_per_cpu *cpu_buffer,
+ struct ftrace_ring_buffer_event *event)
+{
+ unsigned long addr = (unsigned long)event;
+ unsigned long index;
+
+ index = rb_event_index(event);
+ addr &= PAGE_MASK;
+
+ return cpu_buffer->commit_page->page == (void *)addr &&
+ rb_commit_index(cpu_buffer) == index;
+}
+
+static void
+rb_set_commit_to_write(struct ftrace_ring_buffer_per_cpu *cpu_buffer)
+{
+ unsigned long max_count;
+
+ /*
+ * We only race with interrupts and NMIs on this CPU.
+ * If we own the commit event, then we can commit
+ * all others that interrupted us, since the interruptions
+ * are in stack format (they finish before they come
+ * back to us). This allows us to do a simple loop to
+ * assign the commit to the tail.
+ */
+ again:
+ max_count = cpu_buffer->buffer->pages * 100;
+
+ while (cpu_buffer->commit_page != cpu_buffer->tail_page) {
+ if (RB_WARN_ON(cpu_buffer, !(--max_count)))
+ return;
+ if (RB_WARN_ON(cpu_buffer,
+ rb_is_reader_page(cpu_buffer->tail_page)))
+ return;
+ local_set(&cpu_buffer->commit_page->page->commit,
+ rb_page_write(cpu_buffer->commit_page));
+ rb_inc_page(cpu_buffer, &cpu_buffer->commit_page);
+ cpu_buffer->write_stamp =
+ cpu_buffer->commit_page->page->time_stamp;
+ /* add barrier to keep gcc from optimizing too much */
+ barrier();
+ }
+ while (rb_commit_index(cpu_buffer) !=
+ rb_page_write(cpu_buffer->commit_page)) {
+
+ local_set(&cpu_buffer->commit_page->page->commit,
+ rb_page_write(cpu_buffer->commit_page));
+ RB_WARN_ON(cpu_buffer,
+ local_read(&cpu_buffer->commit_page->page->commit) &
+ ~RB_WRITE_MASK);
+ barrier();
+ }
+
+ /* again, keep gcc from optimizing */
+ barrier();
+
+ /*
+ * If an interrupt came in just after the first while loop
+ * and pushed the tail page forward, we will be left with
+ * a dangling commit that will never go forward.
+ */
+ if (unlikely(cpu_buffer->commit_page != cpu_buffer->tail_page))
+ goto again;
+}
+
+static void rb_reset_reader_page(struct ftrace_ring_buffer_per_cpu *cpu_buffer)
+{
+ cpu_buffer->read_stamp = cpu_buffer->reader_page->page->time_stamp;
+ cpu_buffer->reader_page->read = 0;
+}
+
+static void rb_inc_iter(struct ftrace_ring_buffer_iter *iter)
+{
+ struct ftrace_ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer;
+
+ /*
+ * The iterator could be on the reader page (it starts there).
+ * But the head could have moved, since the reader was
+ * found. Check for this case and assign the iterator
+ * to the head page instead of next.
+ */
+ if (iter->head_page == cpu_buffer->reader_page)
+ iter->head_page = rb_set_head_page(cpu_buffer);
+ else
+ rb_inc_page(cpu_buffer, &iter->head_page);
+
+ iter->read_stamp = iter->head_page->page->time_stamp;
+ iter->head = 0;
+}
+
+/**
+ * ftrace_ring_buffer_update_event - update event type and data
+ * @event: the even to update
+ * @type: the type of event
+ * @length: the size of the event field in the ring buffer
+ *
+ * Update the type and data fields of the event. The length
+ * is the actual size that is written to the ring buffer,
+ * and with this, we can determine what to place into the
+ * data field.
+ */
+static void
+rb_update_event(struct ftrace_ring_buffer_event *event,
+ unsigned type, unsigned length)
+{
+ event->type_len = type;
+
+ switch (type) {
+
+ case RINGBUF_TYPE_PADDING:
+ case RINGBUF_TYPE_TIME_EXTEND:
+ case RINGBUF_TYPE_TIME_STAMP:
+ break;
+
+ case 0:
+ length -= RB_EVNT_HDR_SIZE;
+ if (length > RB_MAX_SMALL_DATA || RB_FORCE_8BYTE_ALIGNMENT)
+ event->array[0] = length;
+ else
+ event->type_len = DIV_ROUND_UP(length, RB_ALIGNMENT);
+ break;
+ default:
+ BUG();
+ }
+}
+
+/*
+ * rb_handle_head_page - writer hit the head page
+ *
+ * Returns: +1 to retry page
+ * 0 to continue
+ * -1 on error
+ */
+static int
+rb_handle_head_page(struct ftrace_ring_buffer_per_cpu *cpu_buffer,
+ struct buffer_page *tail_page,
+ struct buffer_page *next_page)
+{
+ struct buffer_page *new_head;
+ int entries;
+ int type;
+ int ret;
+
+ entries = rb_page_entries(next_page);
+
+ /*
+ * The hard part is here. We need to move the head
+ * forward, and protect against both readers on
+ * other CPUs and writers coming in via interrupts.
+ */
+ type = rb_head_page_set_update(cpu_buffer, next_page, tail_page,
+ RB_PAGE_HEAD);
+
+ /*
+ * type can be one of four:
+ * NORMAL - an interrupt already moved it for us
+ * HEAD - we are the first to get here.
+ * UPDATE - we are the interrupt interrupting
+ * a current move.
+ * MOVED - a reader on another CPU moved the next
+ * pointer to its reader page. Give up
+ * and try again.
+ */
+
+ switch (type) {
+ case RB_PAGE_HEAD:
+ /*
+ * We changed the head to UPDATE, thus
+ * it is our responsibility to update
+ * the counters.
+ */
+ local_add(entries, &cpu_buffer->overrun);
+
+ /*
+ * The entries will be zeroed out when we move the
+ * tail page.
+ */
+
+ /* still more to do */
+ break;
+
+ case RB_PAGE_UPDATE:
+ /*
+ * This is an interrupt that interrupt the
+ * previous update. Still more to do.
+ */
+ break;
+ case RB_PAGE_NORMAL:
+ /*
+ * An interrupt came in before the update
+ * and processed this for us.
+ * Nothing left to do.
+ */
+ return 1;
+ case RB_PAGE_MOVED:
+ /*
+ * The reader is on another CPU and just did
+ * a swap with our next_page.
+ * Try again.
+ */
+ return 1;
+ default:
+ RB_WARN_ON(cpu_buffer, 1); /* WTF??? */
+ return -1;
+ }
+
+ /*
+ * Now that we are here, the old head pointer is
+ * set to UPDATE. This will keep the reader from
+ * swapping the head page with the reader page.
+ * The reader (on another CPU) will spin till
+ * we are finished.
+ *
+ * We just need to protect against interrupts
+ * doing the job. We will set the next pointer
+ * to HEAD. After that, we set the old pointer
+ * to NORMAL, but only if it was HEAD before.
+ * otherwise we are an interrupt, and only
+ * want the outer most commit to reset it.
+ */
+ new_head = next_page;
+ rb_inc_page(cpu_buffer, &new_head);
+
+ ret = rb_head_page_set_head(cpu_buffer, new_head, next_page,
+ RB_PAGE_NORMAL);
+
+ /*
+ * Valid returns are:
+ * HEAD - an interrupt came in and already set it.
+ * NORMAL - One of two things:
+ * 1) We really set it.
+ * 2) A bunch of interrupts came in and moved
+ * the page forward again.
+ */
+ switch (ret) {
+ case RB_PAGE_HEAD:
+ case RB_PAGE_NORMAL:
+ /* OK */
+ break;
+ default:
+ RB_WARN_ON(cpu_buffer, 1);
+ return -1;
+ }
+
+ /*
+ * It is possible that an interrupt came in,
+ * set the head up, then more interrupts came in
+ * and moved it again. When we get back here,
+ * the page would have been set to NORMAL but we
+ * just set it back to HEAD.
+ *
+ * How do you detect this? Well, if that happened
+ * the tail page would have moved.
+ */
+ if (ret == RB_PAGE_NORMAL) {
+ /*
+ * If the tail had moved passed next, then we need
+ * to reset the pointer.
+ */
+ if (cpu_buffer->tail_page != tail_page &&
+ cpu_buffer->tail_page != next_page)
+ rb_head_page_set_normal(cpu_buffer, new_head,
+ next_page,
+ RB_PAGE_HEAD);
+ }
+
+ /*
+ * If this was the outer most commit (the one that
+ * changed the original pointer from HEAD to UPDATE),
+ * then it is up to us to reset it to NORMAL.
+ */
+ if (type == RB_PAGE_HEAD) {
+ ret = rb_head_page_set_normal(cpu_buffer, next_page,
+ tail_page,
+ RB_PAGE_UPDATE);
+ if (RB_WARN_ON(cpu_buffer,
+ ret != RB_PAGE_UPDATE))
+ return -1;
+ }
+
+ return 0;
+}
+
+static unsigned rb_calculate_event_length(unsigned length)
+{
+ struct ftrace_ring_buffer_event event; /* Used only for sizeof array */
+
+ /* zero length can cause confusions */
+ if (!length)
+ length = 1;
+
+ if (length > RB_MAX_SMALL_DATA || RB_FORCE_8BYTE_ALIGNMENT)
+ length += sizeof(event.array[0]);
+
+ length += RB_EVNT_HDR_SIZE;
+ length = ALIGN(length, RB_ARCH_ALIGNMENT);
+
+ return length;
+}
+
+static inline void
+rb_reset_tail(struct ftrace_ring_buffer_per_cpu *cpu_buffer,
+ struct buffer_page *tail_page,
+ unsigned long tail, unsigned long length)
+{
+ struct ftrace_ring_buffer_event *event;
+
+ /*
+ * Only the event that crossed the page boundary
+ * must fill the old tail_page with padding.
+ */
+ if (tail >= BUF_PAGE_SIZE) {
+ /*
+ * If the page was filled, then we still need
+ * to update the real_end. Reset it to zero
+ * and the reader will ignore it.
+ */
+ if (tail == BUF_PAGE_SIZE)
+ tail_page->real_end = 0;
+
+ local_sub(length, &tail_page->write);
+ return;
+ }
+
+ event = __rb_page_index(tail_page, tail);
+ kmemcheck_annotate_bitfield(event, bitfield);
+
+ /*
+ * Save the original length to the meta data.
+ * This will be used by the reader to add lost event
+ * counter.
+ */
+ tail_page->real_end = tail;
+
+ /*
+ * If this event is bigger than the minimum size, then
+ * we need to be careful that we don't subtract the
+ * write counter enough to allow another writer to slip
+ * in on this page.
+ * We put in a discarded commit instead, to make sure
+ * that this space is not used again.
+ *
+ * If we are less than the minimum size, we don't need to
+ * worry about it.
+ */
+ if (tail > (BUF_PAGE_SIZE - RB_EVNT_MIN_SIZE)) {
+ /* No room for any events */
+
+ /* Mark the rest of the page with padding */
+ rb_event_set_padding(event);
+
+ /* Set the write back to the previous setting */
+ local_sub(length, &tail_page->write);
+ return;
+ }
+
+ /* Put in a discarded event */
+ event->array[0] = (BUF_PAGE_SIZE - tail) - RB_EVNT_HDR_SIZE;
+ event->type_len = RINGBUF_TYPE_PADDING;
+ /* time delta must be non zero */
+ event->time_delta = 1;
+
+ /* Set write to end of buffer */
+ length = (tail + length) - BUF_PAGE_SIZE;
+ local_sub(length, &tail_page->write);
+}
+
+static struct ftrace_ring_buffer_event *
+rb_move_tail(struct ftrace_ring_buffer_per_cpu *cpu_buffer,
+ unsigned long length, unsigned long tail,
+ struct buffer_page *tail_page, u64 *ts)
+{
+ struct buffer_page *commit_page = cpu_buffer->commit_page;
+ struct ftrace_ring_buffer *buffer = cpu_buffer->buffer;
+ struct buffer_page *next_page;
+ int ret;
+
+ next_page = tail_page;
+
+ rb_inc_page(cpu_buffer, &next_page);
+
+ /*
+ * If for some reason, we had an interrupt storm that made
+ * it all the way around the buffer, bail, and warn
+ * about it.
+ */
+ if (unlikely(next_page == commit_page)) {
+ local_inc(&cpu_buffer->commit_overrun);
+ goto out_reset;
+ }
+
+ /*
+ * This is where the fun begins!
+ *
+ * We are fighting against races between a reader that
+ * could be on another CPU trying to swap its reader
+ * page with the buffer head.
+ *
+ * We are also fighting against interrupts coming in and
+ * moving the head or tail on us as well.
+ *
+ * If the next page is the head page then we have filled
+ * the buffer, unless the commit page is still on the
+ * reader page.
+ */
+ if (rb_is_head_page(cpu_buffer, next_page, &tail_page->list)) {
+
+ /*
+ * If the commit is not on the reader page, then
+ * move the header page.
+ */
+ if (!rb_is_reader_page(cpu_buffer->commit_page)) {
+ /*
+ * If we are not in overwrite mode,
+ * this is easy, just stop here.
+ */
+ if (!(buffer->flags & RB_FL_OVERWRITE))
+ goto out_reset;
+
+ ret = rb_handle_head_page(cpu_buffer,
+ tail_page,
+ next_page);
+ if (ret < 0)
+ goto out_reset;
+ if (ret)
+ goto out_again;
+ } else {
+ /*
+ * We need to be careful here too. The
+ * commit page could still be on the reader
+ * page. We could have a small buffer, and
+ * have filled up the buffer with events
+ * from interrupts and such, and wrapped.
+ *
+ * Note, if the tail page is also the on the
+ * reader_page, we let it move out.
+ */
+ if (unlikely((cpu_buffer->commit_page !=
+ cpu_buffer->tail_page) &&
+ (cpu_buffer->commit_page ==
+ cpu_buffer->reader_page))) {
+ local_inc(&cpu_buffer->commit_overrun);
+ goto out_reset;
+ }
+ }
+ }
+
+ ret = rb_tail_page_update(cpu_buffer, tail_page, next_page);
+ if (ret) {
+ /*
+ * Nested commits always have zero deltas, so
+ * just reread the time stamp
+ */
+ *ts = rb_time_stamp(buffer);
+ next_page->page->time_stamp = *ts;
+ }
+
+ out_again:
+
+ rb_reset_tail(cpu_buffer, tail_page, tail, length);
+
+ /* fail and let the caller try again */
+ return ERR_PTR(-EAGAIN);
+
+ out_reset:
+ /* reset write */
+ rb_reset_tail(cpu_buffer, tail_page, tail, length);
+
+ return NULL;
+}
+
+static struct ftrace_ring_buffer_event *
+__rb_reserve_next(struct ftrace_ring_buffer_per_cpu *cpu_buffer,
+ unsigned type, unsigned long length, u64 *ts)
+{
+ struct buffer_page *tail_page;
+ struct ftrace_ring_buffer_event *event;
+ unsigned long tail, write;
+
+ tail_page = cpu_buffer->tail_page;
+ write = local_add_return(length, &tail_page->write);
+
+ /* set write to only the index of the write */
+ write &= RB_WRITE_MASK;
+ tail = write - length;
+
+ /* See if we shot pass the end of this buffer page */
+ if (write > BUF_PAGE_SIZE)
+ return rb_move_tail(cpu_buffer, length, tail,
+ tail_page, ts);
+
+ /* We reserved something on the buffer */
+
+ event = __rb_page_index(tail_page, tail);
+ kmemcheck_annotate_bitfield(event, bitfield);
+ rb_update_event(event, type, length);
+
+ /* The passed in type is zero for DATA */
+ if (likely(!type))
+ local_inc(&tail_page->entries);
+
+ /*
+ * If this is the first commit on the page, then update
+ * its timestamp.
+ */
+ if (!tail)
+ tail_page->page->time_stamp = *ts;
+
+ return event;
+}
+
+static inline int
+rb_try_to_discard(struct ftrace_ring_buffer_per_cpu *cpu_buffer,
+ struct ftrace_ring_buffer_event *event)
+{
+ unsigned long new_index, old_index;
+ struct buffer_page *bpage;
+ unsigned long index;
+ unsigned long addr;
+
+ new_index = rb_event_index(event);
+ old_index = new_index + rb_event_length(event);
+ addr = (unsigned long)event;
+ addr &= PAGE_MASK;
+
+ bpage = cpu_buffer->tail_page;
+
+ if (bpage->page == (void *)addr && rb_page_write(bpage) == old_index) {
+ unsigned long write_mask =
+ local_read(&bpage->write) & ~RB_WRITE_MASK;
+ /*
+ * This is on the tail page. It is possible that
+ * a write could come in and move the tail page
+ * and write to the next page. That is fine
+ * because we just shorten what is on this page.
+ */
+ old_index += write_mask;
+ new_index += write_mask;
+ index = local_cmpxchg(&bpage->write, old_index, new_index);
+ if (index == old_index)
+ return 1;
+ }
+
+ /* could not discard */
+ return 0;
+}
+
+static int
+rb_add_time_stamp(struct ftrace_ring_buffer_per_cpu *cpu_buffer,
+ u64 *ts, u64 *delta)
+{
+ struct ftrace_ring_buffer_event *event;
+ int ret;
+
+ WARN_ONCE(*delta > (1ULL << 59),
+ KERN_WARNING "Delta way too big! %llu ts=%llu write stamp = %llu\n",
+ (unsigned long long)*delta,
+ (unsigned long long)*ts,
+ (unsigned long long)cpu_buffer->write_stamp);
+
+ /*
+ * The delta is too big, we to add a
+ * new timestamp.
+ */
+ event = __rb_reserve_next(cpu_buffer,
+ RINGBUF_TYPE_TIME_EXTEND,
+ RB_LEN_TIME_EXTEND,
+ ts);
+ if (!event)
+ return -EBUSY;
+
+ if (PTR_ERR(event) == -EAGAIN)
+ return -EAGAIN;
+
+ /* Only a commited time event can update the write stamp */
+ if (rb_event_is_commit(cpu_buffer, event)) {
+ /*
+ * If this is the first on the page, then it was
+ * updated with the page itself. Try to discard it
+ * and if we can't just make it zero.
+ */
+ if (rb_event_index(event)) {
+ event->time_delta = *delta & TS_MASK;
+ event->array[0] = *delta >> TS_SHIFT;
+ } else {
+ /* try to discard, since we do not need this */
+ if (!rb_try_to_discard(cpu_buffer, event)) {
+ /* nope, just zero it */
+ event->time_delta = 0;
+ event->array[0] = 0;
+ }
+ }
+ cpu_buffer->write_stamp = *ts;
+ /* let the caller know this was the commit */
+ ret = 1;
+ } else {
+ /* Try to discard the event */
+ if (!rb_try_to_discard(cpu_buffer, event)) {
+ /* Darn, this is just wasted space */
+ event->time_delta = 0;
+ event->array[0] = 0;
+ }
+ ret = 0;
+ }
+
+ *delta = 0;
+
+ return ret;
+}
+
+static void rb_start_commit(struct ftrace_ring_buffer_per_cpu *cpu_buffer)
+{
+ local_inc(&cpu_buffer->committing);
+ local_inc(&cpu_buffer->commits);
+}
+
+static void rb_end_commit(struct ftrace_ring_buffer_per_cpu *cpu_buffer)
+{
+ unsigned long commits;
+
+ if (RB_WARN_ON(cpu_buffer,
+ !local_read(&cpu_buffer->committing)))
+ return;
+
+ again:
+ commits = local_read(&cpu_buffer->commits);
+ /* synchronize with interrupts */
+ barrier();
+ if (local_read(&cpu_buffer->committing) == 1)
+ rb_set_commit_to_write(cpu_buffer);
+
+ local_dec(&cpu_buffer->committing);
+
+ /* synchronize with interrupts */
+ barrier();
+
+ /*
+ * Need to account for interrupts coming in between the
+ * updating of the commit page and the clearing of the
+ * committing counter.
+ */
+ if (unlikely(local_read(&cpu_buffer->commits) != commits) &&
+ !local_read(&cpu_buffer->committing)) {
+ local_inc(&cpu_buffer->committing);
+ goto again;
+ }
+}
+
+static struct ftrace_ring_buffer_event *
+rb_reserve_next_event(struct ftrace_ring_buffer *buffer,
+ struct ftrace_ring_buffer_per_cpu *cpu_buffer,
+ unsigned long length)
+{
+ struct ftrace_ring_buffer_event *event;
+ u64 ts, delta = 0;
+ int commit = 0;
+ int nr_loops = 0;
+
+ rb_start_commit(cpu_buffer);
+
+#ifdef CONFIG_FTRACE_RING_BUFFER_ALLOW_SWAP
+ /*
+ * Due to the ability to swap a cpu buffer from a buffer
+ * it is possible it was swapped before we committed.
+ * (committing stops a swap). We check for it here and
+ * if it happened, we have to fail the write.
+ */
+ barrier();
+ if (unlikely(ACCESS_ONCE(cpu_buffer->buffer) != buffer)) {
+ local_dec(&cpu_buffer->committing);
+ local_dec(&cpu_buffer->commits);
+ return NULL;
+ }
+#endif
+
+ length = rb_calculate_event_length(length);
+ again:
+ /*
+ * We allow for interrupts to reenter here and do a trace.
+ * If one does, it will cause this original code to loop
+ * back here. Even with heavy interrupts happening, this
+ * should only happen a few times in a row. If this happens
+ * 1000 times in a row, there must be either an interrupt
+ * storm or we have something buggy.
+ * Bail!
+ */
+ if (RB_WARN_ON(cpu_buffer, ++nr_loops > 1000))
+ goto out_fail;
+
+ ts = rb_time_stamp(cpu_buffer->buffer);
+
+ /*
+ * Only the first commit can update the timestamp.
+ * Yes there is a race here. If an interrupt comes in
+ * just after the conditional and it traces too, then it
+ * will also check the deltas. More than one timestamp may
+ * also be made. But only the entry that did the actual
+ * commit will be something other than zero.
+ */
+ if (likely(cpu_buffer->tail_page == cpu_buffer->commit_page &&
+ rb_page_write(cpu_buffer->tail_page) ==
+ rb_commit_index(cpu_buffer))) {
+ u64 diff;
+
+ diff = ts - cpu_buffer->write_stamp;
+
+ /* make sure this diff is calculated here */
+ barrier();
+
+ /* Did the write stamp get updated already? */
+ if (unlikely(ts < cpu_buffer->write_stamp))
+ goto get_event;
+
+ delta = diff;
+ if (unlikely(test_time_stamp(delta))) {
+
+ commit = rb_add_time_stamp(cpu_buffer, &ts, &delta);
+ if (commit == -EBUSY)
+ goto out_fail;
+
+ if (commit == -EAGAIN)
+ goto again;
+
+ RB_WARN_ON(cpu_buffer, commit < 0);
+ }
+ }
+
+ get_event:
+ event = __rb_reserve_next(cpu_buffer, 0, length, &ts);
+ if (unlikely(PTR_ERR(event) == -EAGAIN))
+ goto again;
+
+ if (!event)
+ goto out_fail;
+
+ if (!rb_event_is_commit(cpu_buffer, event))
+ delta = 0;
+
+ event->time_delta = delta;
+
+ return event;
+
+ out_fail:
+ rb_end_commit(cpu_buffer);
+ return NULL;
+}
+
+#ifdef CONFIG_TRACING
+
+#define TRACE_RECURSIVE_DEPTH 16
+
+static int trace_recursive_lock(void)
+{
+ current->trace_recursion++;
+
+ if (likely(current->trace_recursion < TRACE_RECURSIVE_DEPTH))
+ return 0;
+
+ /* Disable all tracing before we do anything else */
+ tracing_off_permanent();
+
+ printk_once(KERN_WARNING "Tracing recursion: depth[%ld]:"
+ "HC[%lu]:SC[%lu]:NMI[%lu]\n",
+ current->trace_recursion,
+ hardirq_count() >> HARDIRQ_SHIFT,
+ softirq_count() >> SOFTIRQ_SHIFT,
+ in_nmi());
+
+ WARN_ON_ONCE(1);
+ return -1;
+}
+
+static void trace_recursive_unlock(void)
+{
+ WARN_ON_ONCE(!current->trace_recursion);
+
+ current->trace_recursion--;
+}
+
+#else
+
+#define trace_recursive_lock() (0)
+#define trace_recursive_unlock() do { } while (0)
+
+#endif
+
+/**
+ * ftrace_ring_buffer_lock_reserve - reserve a part of the buffer
+ * @buffer: the ring buffer to reserve from
+ * @length: the length of the data to reserve (excluding event header)
+ *
+ * Returns a reseverd event on the ring buffer to copy directly to.
+ * The user of this interface will need to get the body to write into
+ * and can use the ftrace_ring_buffer_event_data() interface.
+ *
+ * The length is the length of the data needed, not the event length
+ * which also includes the event header.
+ *
+ * Must be paired with ftrace_ring_buffer_unlock_commit, unless NULL is returned.
+ * If NULL is returned, then nothing has been allocated or locked.
+ */
+struct ftrace_ring_buffer_event *
+ftrace_ring_buffer_lock_reserve(struct ftrace_ring_buffer *buffer, unsigned long length)
+{
+ struct ftrace_ring_buffer_per_cpu *cpu_buffer;
+ struct ftrace_ring_buffer_event *event;
+ int cpu;
+
+ if (ftrace_ring_buffer_flags != RB_BUFFERS_ON)
+ return NULL;
+
+ /* If we are tracing schedule, we don't want to recurse */
+ preempt_disable_notrace();
+
+ if (atomic_read(&buffer->record_disabled))
+ goto out_nocheck;
+
+ if (trace_recursive_lock())
+ goto out_nocheck;
+
+ cpu = raw_smp_processor_id();
+
+ if (!cpumask_test_cpu(cpu, buffer->cpumask))
+ goto out;
+
+ cpu_buffer = buffer->buffers[cpu];
+
+ if (atomic_read(&cpu_buffer->record_disabled))
+ goto out;
+
+ if (length > BUF_MAX_DATA_SIZE)
+ goto out;
+
+ event = rb_reserve_next_event(buffer, cpu_buffer, length);
+ if (!event)
+ goto out;
+
+ return event;
+
+ out:
+ trace_recursive_unlock();
+
+ out_nocheck:
+ preempt_enable_notrace();
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_lock_reserve);
+
+static void
+rb_update_write_stamp(struct ftrace_ring_buffer_per_cpu *cpu_buffer,
+ struct ftrace_ring_buffer_event *event)
+{
+ /*
+ * The event first in the commit queue updates the
+ * time stamp.
+ */
+ if (rb_event_is_commit(cpu_buffer, event))
+ cpu_buffer->write_stamp += event->time_delta;
+}
+
+static void rb_commit(struct ftrace_ring_buffer_per_cpu *cpu_buffer,
+ struct ftrace_ring_buffer_event *event)
+{
+ local_inc(&cpu_buffer->entries);
+ rb_update_write_stamp(cpu_buffer, event);
+ rb_end_commit(cpu_buffer);
+}
+
+/**
+ * ftrace_ring_buffer_unlock_commit - commit a reserved
+ * @buffer: The buffer to commit to
+ * @event: The event pointer to commit.
+ *
+ * This commits the data to the ring buffer, and releases any locks held.
+ *
+ * Must be paired with ftrace_ring_buffer_lock_reserve.
+ */
+int ftrace_ring_buffer_unlock_commit(struct ftrace_ring_buffer *buffer,
+ struct ftrace_ring_buffer_event *event)
+{
+ struct ftrace_ring_buffer_per_cpu *cpu_buffer;
+ int cpu = raw_smp_processor_id();
+
+ cpu_buffer = buffer->buffers[cpu];
+
+ rb_commit(cpu_buffer, event);
+
+ trace_recursive_unlock();
+
+ preempt_enable_notrace();
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_unlock_commit);
+
+static inline void rb_event_discard(struct ftrace_ring_buffer_event *event)
+{
+ /* array[0] holds the actual length for the discarded event */
+ event->array[0] = rb_event_data_length(event) - RB_EVNT_HDR_SIZE;
+ event->type_len = RINGBUF_TYPE_PADDING;
+ /* time delta must be non zero */
+ if (!event->time_delta)
+ event->time_delta = 1;
+}
+
+/*
+ * Decrement the entries to the page that an event is on.
+ * The event does not even need to exist, only the pointer
+ * to the page it is on. This may only be called before the commit
+ * takes place.
+ */
+static inline void
+rb_decrement_entry(struct ftrace_ring_buffer_per_cpu *cpu_buffer,
+ struct ftrace_ring_buffer_event *event)
+{
+ unsigned long addr = (unsigned long)event;
+ struct buffer_page *bpage = cpu_buffer->commit_page;
+ struct buffer_page *start;
+
+ addr &= PAGE_MASK;
+
+ /* Do the likely case first */
+ if (likely(bpage->page == (void *)addr)) {
+ local_dec(&bpage->entries);
+ return;
+ }
+
+ /*
+ * Because the commit page may be on the reader page we
+ * start with the next page and check the end loop there.
+ */
+ rb_inc_page(cpu_buffer, &bpage);
+ start = bpage;
+ do {
+ if (bpage->page == (void *)addr) {
+ local_dec(&bpage->entries);
+ return;
+ }
+ rb_inc_page(cpu_buffer, &bpage);
+ } while (bpage != start);
+
+ /* commit not part of this buffer?? */
+ RB_WARN_ON(cpu_buffer, 1);
+}
+
+/**
+ * ftrace_ring_buffer_commit_discard - discard an event that has not been committed
+ * @buffer: the ring buffer
+ * @event: non committed event to discard
+ *
+ * Sometimes an event that is in the ring buffer needs to be ignored.
+ * This function lets the user discard an event in the ring buffer
+ * and then that event will not be read later.
+ *
+ * This function only works if it is called before the the item has been
+ * committed. It will try to free the event from the ring buffer
+ * if another event has not been added behind it.
+ *
+ * If another event has been added behind it, it will set the event
+ * up as discarded, and perform the commit.
+ *
+ * If this function is called, do not call ftrace_ring_buffer_unlock_commit on
+ * the event.
+ */
+void ftrace_ring_buffer_discard_commit(struct ftrace_ring_buffer *buffer,
+ struct ftrace_ring_buffer_event *event)
+{
+ struct ftrace_ring_buffer_per_cpu *cpu_buffer;
+ int cpu;
+
+ /* The event is discarded regardless */
+ rb_event_discard(event);
+
+ cpu = smp_processor_id();
+ cpu_buffer = buffer->buffers[cpu];
+
+ /*
+ * This must only be called if the event has not been
+ * committed yet. Thus we can assume that preemption
+ * is still disabled.
+ */
+ RB_WARN_ON(buffer, !local_read(&cpu_buffer->committing));
+
+ rb_decrement_entry(cpu_buffer, event);
+ if (rb_try_to_discard(cpu_buffer, event))
+ goto out;
+
+ /*
+ * The commit is still visible by the reader, so we
+ * must still update the timestamp.
+ */
+ rb_update_write_stamp(cpu_buffer, event);
+ out:
+ rb_end_commit(cpu_buffer);
+
+ trace_recursive_unlock();
+
+ preempt_enable_notrace();
+
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_discard_commit);
+
+/**
+ * ftrace_ring_buffer_write - write data to the buffer without reserving
+ * @buffer: The ring buffer to write to.
+ * @length: The length of the data being written (excluding the event header)
+ * @data: The data to write to the buffer.
+ *
+ * This is like ftrace_ring_buffer_lock_reserve and ftrace_ring_buffer_unlock_commit as
+ * one function. If you already have the data to write to the buffer, it
+ * may be easier to simply call this function.
+ *
+ * Note, like ftrace_ring_buffer_lock_reserve, the length is the length of the data
+ * and not the length of the event which would hold the header.
+ */
+int ftrace_ring_buffer_write(struct ftrace_ring_buffer *buffer,
+ unsigned long length,
+ void *data)
+{
+ struct ftrace_ring_buffer_per_cpu *cpu_buffer;
+ struct ftrace_ring_buffer_event *event;
+ void *body;
+ int ret = -EBUSY;
+ int cpu;
+
+ if (ftrace_ring_buffer_flags != RB_BUFFERS_ON)
+ return -EBUSY;
+
+ preempt_disable_notrace();
+
+ if (atomic_read(&buffer->record_disabled))
+ goto out;
+
+ cpu = raw_smp_processor_id();
+
+ if (!cpumask_test_cpu(cpu, buffer->cpumask))
+ goto out;
+
+ cpu_buffer = buffer->buffers[cpu];
+
+ if (atomic_read(&cpu_buffer->record_disabled))
+ goto out;
+
+ if (length > BUF_MAX_DATA_SIZE)
+ goto out;
+
+ event = rb_reserve_next_event(buffer, cpu_buffer, length);
+ if (!event)
+ goto out;
+
+ body = rb_event_data(event);
+
+ memcpy(body, data, length);
+
+ rb_commit(cpu_buffer, event);
+
+ ret = 0;
+ out:
+ preempt_enable_notrace();
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_write);
+
+static int rb_per_cpu_empty(struct ftrace_ring_buffer_per_cpu *cpu_buffer)
+{
+ struct buffer_page *reader = cpu_buffer->reader_page;
+ struct buffer_page *head = rb_set_head_page(cpu_buffer);
+ struct buffer_page *commit = cpu_buffer->commit_page;
+
+ /* In case of error, head will be NULL */
+ if (unlikely(!head))
+ return 1;
+
+ return reader->read == rb_page_commit(reader) &&
+ (commit == reader ||
+ (commit == head &&
+ head->read == rb_page_commit(commit)));
+}
+
+/**
+ * ftrace_ring_buffer_record_disable - stop all writes into the buffer
+ * @buffer: The ring buffer to stop writes to.
+ *
+ * This prevents all writes to the buffer. Any attempt to write
+ * to the buffer after this will fail and return NULL.
+ *
+ * The caller should call synchronize_sched() after this.
+ */
+void ftrace_ring_buffer_record_disable(struct ftrace_ring_buffer *buffer)
+{
+ atomic_inc(&buffer->record_disabled);
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_record_disable);
+
+/**
+ * ftrace_ring_buffer_record_enable - enable writes to the buffer
+ * @buffer: The ring buffer to enable writes
+ *
+ * Note, multiple disables will need the same number of enables
+ * to truly enable the writing (much like preempt_disable).
+ */
+void ftrace_ring_buffer_record_enable(struct ftrace_ring_buffer *buffer)
+{
+ atomic_dec(&buffer->record_disabled);
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_record_enable);
+
+/**
+ * ftrace_ring_buffer_record_disable_cpu - stop all writes into the cpu_buffer
+ * @buffer: The ring buffer to stop writes to.
+ * @cpu: The CPU buffer to stop
+ *
+ * This prevents all writes to the buffer. Any attempt to write
+ * to the buffer after this will fail and return NULL.
+ *
+ * The caller should call synchronize_sched() after this.
+ */
+void ftrace_ring_buffer_record_disable_cpu(struct ftrace_ring_buffer *buffer, int cpu)
+{
+ struct ftrace_ring_buffer_per_cpu *cpu_buffer;
+
+ if (!cpumask_test_cpu(cpu, buffer->cpumask))
+ return;
+
+ cpu_buffer = buffer->buffers[cpu];
+ atomic_inc(&cpu_buffer->record_disabled);
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_record_disable_cpu);
+
+/**
+ * ftrace_ring_buffer_record_enable_cpu - enable writes to the buffer
+ * @buffer: The ring buffer to enable writes
+ * @cpu: The CPU to enable.
+ *
+ * Note, multiple disables will need the same number of enables
+ * to truly enable the writing (much like preempt_disable).
+ */
+void ftrace_ring_buffer_record_enable_cpu(struct ftrace_ring_buffer *buffer, int cpu)
+{
+ struct ftrace_ring_buffer_per_cpu *cpu_buffer;
+
+ if (!cpumask_test_cpu(cpu, buffer->cpumask))
+ return;
+
+ cpu_buffer = buffer->buffers[cpu];
+ atomic_dec(&cpu_buffer->record_disabled);
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_record_enable_cpu);
+
+/**
+ * ftrace_ring_buffer_entries_cpu - get the number of entries in a cpu buffer
+ * @buffer: The ring buffer
+ * @cpu: The per CPU buffer to get the entries from.
+ */
+unsigned long ftrace_ring_buffer_entries_cpu(struct ftrace_ring_buffer *buffer, int cpu)
+{
+ struct ftrace_ring_buffer_per_cpu *cpu_buffer;
+ unsigned long ret;
+
+ if (!cpumask_test_cpu(cpu, buffer->cpumask))
+ return 0;
+
+ cpu_buffer = buffer->buffers[cpu];
+ ret = (local_read(&cpu_buffer->entries) - local_read(&cpu_buffer->overrun))
+ - cpu_buffer->read;
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_entries_cpu);
+
+/**
+ * ftrace_ring_buffer_overrun_cpu - get the number of overruns in a cpu_buffer
+ * @buffer: The ring buffer
+ * @cpu: The per CPU buffer to get the number of overruns from
+ */
+unsigned long ftrace_ring_buffer_overrun_cpu(struct ftrace_ring_buffer *buffer, int cpu)
+{
+ struct ftrace_ring_buffer_per_cpu *cpu_buffer;
+ unsigned long ret;
+
+ if (!cpumask_test_cpu(cpu, buffer->cpumask))
+ return 0;
+
+ cpu_buffer = buffer->buffers[cpu];
+ ret = local_read(&cpu_buffer->overrun);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_overrun_cpu);
+
+/**
+ * ftrace_ring_buffer_commit_overrun_cpu - get the number of overruns caused by commits
+ * @buffer: The ring buffer
+ * @cpu: The per CPU buffer to get the number of overruns from
+ */
+unsigned long
+ftrace_ring_buffer_commit_overrun_cpu(struct ftrace_ring_buffer *buffer, int cpu)
+{
+ struct ftrace_ring_buffer_per_cpu *cpu_buffer;
+ unsigned long ret;
+
+ if (!cpumask_test_cpu(cpu, buffer->cpumask))
+ return 0;
+
+ cpu_buffer = buffer->buffers[cpu];
+ ret = local_read(&cpu_buffer->commit_overrun);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_commit_overrun_cpu);
+
+/**
+ * ftrace_ring_buffer_entries - get the number of entries in a buffer
+ * @buffer: The ring buffer
+ *
+ * Returns the total number of entries in the ring buffer
+ * (all CPU entries)
+ */
+unsigned long ftrace_ring_buffer_entries(struct ftrace_ring_buffer *buffer)
+{
+ struct ftrace_ring_buffer_per_cpu *cpu_buffer;
+ unsigned long entries = 0;
+ int cpu;
+
+ /* if you care about this being correct, lock the buffer */
+ for_each_buffer_cpu(buffer, cpu) {
+ cpu_buffer = buffer->buffers[cpu];
+ entries += (local_read(&cpu_buffer->entries) -
+ local_read(&cpu_buffer->overrun)) - cpu_buffer->read;
+ }
+
+ return entries;
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_entries);
+
+/**
+ * ftrace_ring_buffer_overruns - get the number of overruns in buffer
+ * @buffer: The ring buffer
+ *
+ * Returns the total number of overruns in the ring buffer
+ * (all CPU entries)
+ */
+unsigned long ftrace_ring_buffer_overruns(struct ftrace_ring_buffer *buffer)
+{
+ struct ftrace_ring_buffer_per_cpu *cpu_buffer;
+ unsigned long overruns = 0;
+ int cpu;
+
+ /* if you care about this being correct, lock the buffer */
+ for_each_buffer_cpu(buffer, cpu) {
+ cpu_buffer = buffer->buffers[cpu];
+ overruns += local_read(&cpu_buffer->overrun);
+ }
+
+ return overruns;
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_overruns);
+
+static void rb_iter_reset(struct ftrace_ring_buffer_iter *iter)
+{
+ struct ftrace_ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer;
+
+ /* Iterator usage is expected to have record disabled */
+ if (list_empty(&cpu_buffer->reader_page->list)) {
+ iter->head_page = rb_set_head_page(cpu_buffer);
+ if (unlikely(!iter->head_page))
+ return;
+ iter->head = iter->head_page->read;
+ } else {
+ iter->head_page = cpu_buffer->reader_page;
+ iter->head = cpu_buffer->reader_page->read;
+ }
+ if (iter->head)
+ iter->read_stamp = cpu_buffer->read_stamp;
+ else
+ iter->read_stamp = iter->head_page->page->time_stamp;
+ iter->cache_reader_page = cpu_buffer->reader_page;
+ iter->cache_read = cpu_buffer->read;
+}
+
+/**
+ * ftrace_ring_buffer_iter_reset - reset an iterator
+ * @iter: The iterator to reset
+ *
+ * Resets the iterator, so that it will start from the beginning
+ * again.
+ */
+void ftrace_ring_buffer_iter_reset(struct ftrace_ring_buffer_iter *iter)
+{
+ struct ftrace_ring_buffer_per_cpu *cpu_buffer;
+ unsigned long flags;
+
+ if (!iter)
+ return;
+
+ cpu_buffer = iter->cpu_buffer;
+
+ spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+ rb_iter_reset(iter);
+ spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_iter_reset);
+
+/**
+ * ftrace_ring_buffer_iter_empty - check if an iterator has no more to read
+ * @iter: The iterator to check
+ */
+int ftrace_ring_buffer_iter_empty(struct ftrace_ring_buffer_iter *iter)
+{
+ struct ftrace_ring_buffer_per_cpu *cpu_buffer;
+
+ cpu_buffer = iter->cpu_buffer;
+
+ return iter->head_page == cpu_buffer->commit_page &&
+ iter->head == rb_commit_index(cpu_buffer);
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_iter_empty);
+
+static void
+rb_update_read_stamp(struct ftrace_ring_buffer_per_cpu *cpu_buffer,
+ struct ftrace_ring_buffer_event *event)
+{
+ u64 delta;
+
+ switch (event->type_len) {
+ case RINGBUF_TYPE_PADDING:
+ return;
+
+ case RINGBUF_TYPE_TIME_EXTEND:
+ delta = event->array[0];
+ delta <<= TS_SHIFT;
+ delta += event->time_delta;
+ cpu_buffer->read_stamp += delta;
+ return;
+
+ case RINGBUF_TYPE_TIME_STAMP:
+ /* FIXME: not implemented */
+ return;
+
+ case RINGBUF_TYPE_DATA:
+ cpu_buffer->read_stamp += event->time_delta;
+ return;
+
+ default:
+ BUG();
+ }
+ return;
+}
+
+static void
+rb_update_iter_read_stamp(struct ftrace_ring_buffer_iter *iter,
+ struct ftrace_ring_buffer_event *event)
+{
+ u64 delta;
+
+ switch (event->type_len) {
+ case RINGBUF_TYPE_PADDING:
+ return;
+
+ case RINGBUF_TYPE_TIME_EXTEND:
+ delta = event->array[0];
+ delta <<= TS_SHIFT;
+ delta += event->time_delta;
+ iter->read_stamp += delta;
+ return;
+
+ case RINGBUF_TYPE_TIME_STAMP:
+ /* FIXME: not implemented */
+ return;
+
+ case RINGBUF_TYPE_DATA:
+ iter->read_stamp += event->time_delta;
+ return;
+
+ default:
+ BUG();
+ }
+ return;
+}
+
+static struct buffer_page *
+rb_get_reader_page(struct ftrace_ring_buffer_per_cpu *cpu_buffer)
+{
+ struct buffer_page *reader = NULL;
+ unsigned long overwrite;
+ unsigned long flags;
+ int nr_loops = 0;
+ int ret;
+
+ local_irq_save(flags);
+ arch_spin_lock(&cpu_buffer->lock);
+
+ again:
+ /*
+ * This should normally only loop twice. But because the
+ * start of the reader inserts an empty page, it causes
+ * a case where we will loop three times. There should be no
+ * reason to loop four times (that I know of).
+ */
+ if (RB_WARN_ON(cpu_buffer, ++nr_loops > 3)) {
+ reader = NULL;
+ goto out;
+ }
+
+ reader = cpu_buffer->reader_page;
+
+ /* If there's more to read, return this page */
+ if (cpu_buffer->reader_page->read < rb_page_size(reader))
+ goto out;
+
+ /* Never should we have an index greater than the size */
+ if (RB_WARN_ON(cpu_buffer,
+ cpu_buffer->reader_page->read > rb_page_size(reader)))
+ goto out;
+
+ /* check if we caught up to the tail */
+ reader = NULL;
+ if (cpu_buffer->commit_page == cpu_buffer->reader_page)
+ goto out;
+
+ /*
+ * Reset the reader page to size zero.
+ */
+ local_set(&cpu_buffer->reader_page->write, 0);
+ local_set(&cpu_buffer->reader_page->entries, 0);
+ local_set(&cpu_buffer->reader_page->page->commit, 0);
+ cpu_buffer->reader_page->real_end = 0;
+
+ spin:
+ /*
+ * Splice the empty reader page into the list around the head.
+ */
+ reader = rb_set_head_page(cpu_buffer);
+ cpu_buffer->reader_page->list.next = rb_list_head(reader->list.next);
+ cpu_buffer->reader_page->list.prev = reader->list.prev;
+
+ /*
+ * cpu_buffer->pages just needs to point to the buffer, it
+ * has no specific buffer page to point to. Lets move it out
+ * of our way so we don't accidently swap it.
+ */
+ cpu_buffer->pages = reader->list.prev;
+
+ /* The reader page will be pointing to the new head */
+ rb_set_list_to_head(cpu_buffer, &cpu_buffer->reader_page->list);
+
+ /*
+ * We want to make sure we read the overruns after we set up our
+ * pointers to the next object. The writer side does a
+ * cmpxchg to cross pages which acts as the mb on the writer
+ * side. Note, the reader will constantly fail the swap
+ * while the writer is updating the pointers, so this
+ * guarantees that the overwrite recorded here is the one we
+ * want to compare with the last_overrun.
+ */
+ smp_mb();
+ overwrite = local_read(&(cpu_buffer->overrun));
+
+ /*
+ * Here's the tricky part.
+ *
+ * We need to move the pointer past the header page.
+ * But we can only do that if a writer is not currently
+ * moving it. The page before the header page has the
+ * flag bit '1' set if it is pointing to the page we want.
+ * but if the writer is in the process of moving it
+ * than it will be '2' or already moved '0'.
+ */
+
+ ret = rb_head_page_replace(reader, cpu_buffer->reader_page);
+
+ /*
+ * If we did not convert it, then we must try again.
+ */
+ if (!ret)
+ goto spin;
+
+ /*
+ * Yeah! We succeeded in replacing the page.
+ *
+ * Now make the new head point back to the reader page.
+ */
+ rb_list_head(reader->list.next)->prev = &cpu_buffer->reader_page->list;
+ rb_inc_page(cpu_buffer, &cpu_buffer->head_page);
+
+ /* Finally update the reader page to the new head */
+ cpu_buffer->reader_page = reader;
+ rb_reset_reader_page(cpu_buffer);
+
+ if (overwrite != cpu_buffer->last_overrun) {
+ cpu_buffer->lost_events = overwrite - cpu_buffer->last_overrun;
+ cpu_buffer->last_overrun = overwrite;
+ }
+
+ goto again;
+
+ out:
+ arch_spin_unlock(&cpu_buffer->lock);
+ local_irq_restore(flags);
+
+ return reader;
+}
+
+static void rb_advance_reader(struct ftrace_ring_buffer_per_cpu *cpu_buffer)
+{
+ struct ftrace_ring_buffer_event *event;
+ struct buffer_page *reader;
+ unsigned length;
+
+ reader = rb_get_reader_page(cpu_buffer);
+
+ /* This function should not be called when buffer is empty */
+ if (RB_WARN_ON(cpu_buffer, !reader))
+ return;
+
+ event = rb_reader_event(cpu_buffer);
+
+ if (event->type_len <= RINGBUF_TYPE_DATA_TYPE_LEN_MAX)
+ cpu_buffer->read++;
+
+ rb_update_read_stamp(cpu_buffer, event);
+
+ length = rb_event_length(event);
+ cpu_buffer->reader_page->read += length;
+}
+
+static void rb_advance_iter(struct ftrace_ring_buffer_iter *iter)
+{
+ struct ftrace_ring_buffer *buffer;
+ struct ftrace_ring_buffer_per_cpu *cpu_buffer;
+ struct ftrace_ring_buffer_event *event;
+ unsigned length;
+
+ cpu_buffer = iter->cpu_buffer;
+ buffer = cpu_buffer->buffer;
+
+ /*
+ * Check if we are at the end of the buffer.
+ */
+ if (iter->head >= rb_page_size(iter->head_page)) {
+ /* discarded commits can make the page empty */
+ if (iter->head_page == cpu_buffer->commit_page)
+ return;
+ rb_inc_iter(iter);
+ return;
+ }
+
+ event = rb_iter_head_event(iter);
+
+ length = rb_event_length(event);
+
+ /*
+ * This should not be called to advance the header if we are
+ * at the tail of the buffer.
+ */
+ if (RB_WARN_ON(cpu_buffer,
+ (iter->head_page == cpu_buffer->commit_page) &&
+ (iter->head + length > rb_commit_index(cpu_buffer))))
+ return;
+
+ rb_update_iter_read_stamp(iter, event);
+
+ iter->head += length;
+
+ /* check for end of page padding */
+ if ((iter->head >= rb_page_size(iter->head_page)) &&
+ (iter->head_page != cpu_buffer->commit_page))
+ rb_advance_iter(iter);
+}
+
+static int rb_lost_events(struct ftrace_ring_buffer_per_cpu *cpu_buffer)
+{
+ return cpu_buffer->lost_events;
+}
+
+static struct ftrace_ring_buffer_event *
+rb_buffer_peek(struct ftrace_ring_buffer_per_cpu *cpu_buffer, u64 *ts,
+ unsigned long *lost_events)
+{
+ struct ftrace_ring_buffer_event *event;
+ struct buffer_page *reader;
+ int nr_loops = 0;
+
+ again:
+ /*
+ * We repeat when a timestamp is encountered. It is possible
+ * to get multiple timestamps from an interrupt entering just
+ * as one timestamp is about to be written, or from discarded
+ * commits. The most that we can have is the number on a single page.
+ */
+ if (RB_WARN_ON(cpu_buffer, ++nr_loops > RB_TIMESTAMPS_PER_PAGE))
+ return NULL;
+
+ reader = rb_get_reader_page(cpu_buffer);
+ if (!reader)
+ return NULL;
+
+ event = rb_reader_event(cpu_buffer);
+
+ switch (event->type_len) {
+ case RINGBUF_TYPE_PADDING:
+ if (rb_null_event(event))
+ RB_WARN_ON(cpu_buffer, 1);
+ /*
+ * Because the writer could be discarding every
+ * event it creates (which would probably be bad)
+ * if we were to go back to "again" then we may never
+ * catch up, and will trigger the warn on, or lock
+ * the box. Return the padding, and we will release
+ * the current locks, and try again.
+ */
+ return event;
+
+ case RINGBUF_TYPE_TIME_EXTEND:
+ /* Internal data, OK to advance */
+ rb_advance_reader(cpu_buffer);
+ goto again;
+
+ case RINGBUF_TYPE_TIME_STAMP:
+ /* FIXME: not implemented */
+ rb_advance_reader(cpu_buffer);
+ goto again;
+
+ case RINGBUF_TYPE_DATA:
+ if (ts) {
+ *ts = cpu_buffer->read_stamp + event->time_delta;
+ ftrace_ring_buffer_normalize_time_stamp(cpu_buffer->buffer,
+ cpu_buffer->cpu, ts);
+ }
+ if (lost_events)
+ *lost_events = rb_lost_events(cpu_buffer);
+ return event;
+
+ default:
+ BUG();
+ }
+
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_peek);
+
+static struct ftrace_ring_buffer_event *
+rb_iter_peek(struct ftrace_ring_buffer_iter *iter, u64 *ts)
+{
+ struct ftrace_ring_buffer *buffer;
+ struct ftrace_ring_buffer_per_cpu *cpu_buffer;
+ struct ftrace_ring_buffer_event *event;
+ int nr_loops = 0;
+
+ cpu_buffer = iter->cpu_buffer;
+ buffer = cpu_buffer->buffer;
+
+ /*
+ * Check if someone performed a consuming read to
+ * the buffer. A consuming read invalidates the iterator
+ * and we need to reset the iterator in this case.
+ */
+ if (unlikely(iter->cache_read != cpu_buffer->read ||
+ iter->cache_reader_page != cpu_buffer->reader_page))
+ rb_iter_reset(iter);
+
+ again:
+ if (ftrace_ring_buffer_iter_empty(iter))
+ return NULL;
+
+ /*
+ * We repeat when a timestamp is encountered.
+ * We can get multiple timestamps by nested interrupts or also
+ * if filtering is on (discarding commits). Since discarding
+ * commits can be frequent we can get a lot of timestamps.
+ * But we limit them by not adding timestamps if they begin
+ * at the start of a page.
+ */
+ if (RB_WARN_ON(cpu_buffer, ++nr_loops > RB_TIMESTAMPS_PER_PAGE))
+ return NULL;
+
+ if (rb_per_cpu_empty(cpu_buffer))
+ return NULL;
+
+ if (iter->head >= local_read(&iter->head_page->page->commit)) {
+ rb_inc_iter(iter);
+ goto again;
+ }
+
+ event = rb_iter_head_event(iter);
+
+ switch (event->type_len) {
+ case RINGBUF_TYPE_PADDING:
+ if (rb_null_event(event)) {
+ rb_inc_iter(iter);
+ goto again;
+ }
+ rb_advance_iter(iter);
+ return event;
+
+ case RINGBUF_TYPE_TIME_EXTEND:
+ /* Internal data, OK to advance */
+ rb_advance_iter(iter);
+ goto again;
+
+ case RINGBUF_TYPE_TIME_STAMP:
+ /* FIXME: not implemented */
+ rb_advance_iter(iter);
+ goto again;
+
+ case RINGBUF_TYPE_DATA:
+ if (ts) {
+ *ts = iter->read_stamp + event->time_delta;
+ ftrace_ring_buffer_normalize_time_stamp(buffer,
+ cpu_buffer->cpu, ts);
+ }
+ return event;
+
+ default:
+ BUG();
+ }
+
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_iter_peek);
+
+static inline int rb_ok_to_lock(void)
+{
+ /*
+ * If an NMI die dumps out the content of the ring buffer
+ * do not grab locks. We also permanently disable the ring
+ * buffer too. A one time deal is all you get from reading
+ * the ring buffer from an NMI.
+ */
+ if (likely(!in_nmi()))
+ return 1;
+
+ tracing_off_permanent();
+ return 0;
+}
+
+/**
+ * ftrace_ring_buffer_peek - peek at the next event to be read
+ * @buffer: The ring buffer to read
+ * @cpu: The cpu to peak at
+ * @ts: The timestamp counter of this event.
+ * @lost_events: a variable to store if events were lost (may be NULL)
+ *
+ * This will return the event that will be read next, but does
+ * not consume the data.
+ */
+struct ftrace_ring_buffer_event *
+ftrace_ring_buffer_peek(struct ftrace_ring_buffer *buffer, int cpu, u64 *ts,
+ unsigned long *lost_events)
+{
+ struct ftrace_ring_buffer_per_cpu *cpu_buffer = buffer->buffers[cpu];
+ struct ftrace_ring_buffer_event *event;
+ unsigned long flags;
+ int dolock;
+
+ if (!cpumask_test_cpu(cpu, buffer->cpumask))
+ return NULL;
+
+ dolock = rb_ok_to_lock();
+ again:
+ local_irq_save(flags);
+ if (dolock)
+ spin_lock(&cpu_buffer->reader_lock);
+ event = rb_buffer_peek(cpu_buffer, ts, lost_events);
+ if (event && event->type_len == RINGBUF_TYPE_PADDING)
+ rb_advance_reader(cpu_buffer);
+ if (dolock)
+ spin_unlock(&cpu_buffer->reader_lock);
+ local_irq_restore(flags);
+
+ if (event && event->type_len == RINGBUF_TYPE_PADDING)
+ goto again;
+
+ return event;
+}
+
+/**
+ * ftrace_ring_buffer_iter_peek - peek at the next event to be read
+ * @iter: The ring buffer iterator
+ * @ts: The timestamp counter of this event.
+ *
+ * This will return the event that will be read next, but does
+ * not increment the iterator.
+ */
+struct ftrace_ring_buffer_event *
+ftrace_ring_buffer_iter_peek(struct ftrace_ring_buffer_iter *iter, u64 *ts)
+{
+ struct ftrace_ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer;
+ struct ftrace_ring_buffer_event *event;
+ unsigned long flags;
+
+ again:
+ spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+ event = rb_iter_peek(iter, ts);
+ spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+
+ if (event && event->type_len == RINGBUF_TYPE_PADDING)
+ goto again;
+
+ return event;
+}
+
+/**
+ * ftrace_ring_buffer_consume - return an event and consume it
+ * @buffer: The ring buffer to get the next event from
+ * @cpu: the cpu to read the buffer from
+ * @ts: a variable to store the timestamp (may be NULL)
+ * @lost_events: a variable to store if events were lost (may be NULL)
+ *
+ * Returns the next event in the ring buffer, and that event is consumed.
+ * Meaning, that sequential reads will keep returning a different event,
+ * and eventually empty the ring buffer if the producer is slower.
+ */
+struct ftrace_ring_buffer_event *
+ftrace_ring_buffer_consume(struct ftrace_ring_buffer *buffer, int cpu, u64 *ts,
+ unsigned long *lost_events)
+{
+ struct ftrace_ring_buffer_per_cpu *cpu_buffer;
+ struct ftrace_ring_buffer_event *event = NULL;
+ unsigned long flags;
+ int dolock;
+
+ dolock = rb_ok_to_lock();
+
+ again:
+ /* might be called in atomic */
+ preempt_disable();
+
+ if (!cpumask_test_cpu(cpu, buffer->cpumask))
+ goto out;
+
+ cpu_buffer = buffer->buffers[cpu];
+ local_irq_save(flags);
+ if (dolock)
+ spin_lock(&cpu_buffer->reader_lock);
+
+ event = rb_buffer_peek(cpu_buffer, ts, lost_events);
+ if (event) {
+ cpu_buffer->lost_events = 0;
+ rb_advance_reader(cpu_buffer);
+ }
+
+ if (dolock)
+ spin_unlock(&cpu_buffer->reader_lock);
+ local_irq_restore(flags);
+
+ out:
+ preempt_enable();
+
+ if (event && event->type_len == RINGBUF_TYPE_PADDING)
+ goto again;
+
+ return event;
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_consume);
+
+/**
+ * ftrace_ring_buffer_read_prepare - Prepare for a non consuming read of the buffer
+ * @buffer: The ring buffer to read from
+ * @cpu: The cpu buffer to iterate over
+ *
+ * This performs the initial preparations necessary to iterate
+ * through the buffer. Memory is allocated, buffer recording
+ * is disabled, and the iterator pointer is returned to the caller.
+ *
+ * Disabling buffer recordng prevents the reading from being
+ * corrupted. This is not a consuming read, so a producer is not
+ * expected.
+ *
+ * After a sequence of ftrace_ring_buffer_read_prepare calls, the user is
+ * expected to make at least one call to ftrace_ring_buffer_prepare_sync.
+ * Afterwards, ftrace_ring_buffer_read_start is invoked to get things going
+ * for real.
+ *
+ * This overall must be paired with ftrace_ring_buffer_finish.
+ */
+struct ftrace_ring_buffer_iter *
+ftrace_ring_buffer_read_prepare(struct ftrace_ring_buffer *buffer, int cpu)
+{
+ struct ftrace_ring_buffer_per_cpu *cpu_buffer;
+ struct ftrace_ring_buffer_iter *iter;
+
+ if (!cpumask_test_cpu(cpu, buffer->cpumask))
+ return NULL;
+
+ iter = kmalloc(sizeof(*iter), GFP_KERNEL);
+ if (!iter)
+ return NULL;
+
+ cpu_buffer = buffer->buffers[cpu];
+
+ iter->cpu_buffer = cpu_buffer;
+
+ atomic_inc(&cpu_buffer->record_disabled);
+
+ return iter;
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_read_prepare);
+
+/**
+ * ftrace_ring_buffer_read_prepare_sync - Synchronize a set of prepare calls
+ *
+ * All previously invoked ftrace_ring_buffer_read_prepare calls to prepare
+ * iterators will be synchronized. Afterwards, read_buffer_read_start
+ * calls on those iterators are allowed.
+ */
+void
+ftrace_ring_buffer_read_prepare_sync(void)
+{
+ synchronize_sched();
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_read_prepare_sync);
+
+/**
+ * ftrace_ring_buffer_read_start - start a non consuming read of the buffer
+ * @iter: The iterator returned by ftrace_ring_buffer_read_prepare
+ *
+ * This finalizes the startup of an iteration through the buffer.
+ * The iterator comes from a call to ftrace_ring_buffer_read_prepare and
+ * an intervening ftrace_ring_buffer_read_prepare_sync must have been
+ * performed.
+ *
+ * Must be paired with ftrace_ring_buffer_finish.
+ */
+void
+ftrace_ring_buffer_read_start(struct ftrace_ring_buffer_iter *iter)
+{
+ struct ftrace_ring_buffer_per_cpu *cpu_buffer;
+ unsigned long flags;
+
+ if (!iter)
+ return;
+
+ cpu_buffer = iter->cpu_buffer;
+
+ spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+ arch_spin_lock(&cpu_buffer->lock);
+ rb_iter_reset(iter);
+ arch_spin_unlock(&cpu_buffer->lock);
+ spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_read_start);
+
+/**
+ * ftrace_ring_buffer_finish - finish reading the iterator of the buffer
+ * @iter: The iterator retrieved by ftrace_ring_buffer_start
+ *
+ * This re-enables the recording to the buffer, and frees the
+ * iterator.
+ */
+void
+ftrace_ring_buffer_read_finish(struct ftrace_ring_buffer_iter *iter)
+{
+ struct ftrace_ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer;
+
+ atomic_dec(&cpu_buffer->record_disabled);
+ kfree(iter);
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_read_finish);
+
+/**
+ * ftrace_ring_buffer_read - read the next item in the ring buffer by the iterator
+ * @iter: The ring buffer iterator
+ * @ts: The time stamp of the event read.
+ *
+ * This reads the next event in the ring buffer and increments the iterator.
+ */
+struct ftrace_ring_buffer_event *
+ftrace_ring_buffer_read(struct ftrace_ring_buffer_iter *iter, u64 *ts)
+{
+ struct ftrace_ring_buffer_event *event;
+ struct ftrace_ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer;
+ unsigned long flags;
+
+ spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+ again:
+ event = rb_iter_peek(iter, ts);
+ if (!event)
+ goto out;
+
+ if (event->type_len == RINGBUF_TYPE_PADDING)
+ goto again;
+
+ rb_advance_iter(iter);
+ out:
+ spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+
+ return event;
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_read);
+
+/**
+ * ftrace_ring_buffer_size - return the size of the ring buffer (in bytes)
+ * @buffer: The ring buffer.
+ */
+unsigned long ftrace_ring_buffer_size(struct ftrace_ring_buffer *buffer)
+{
+ return BUF_PAGE_SIZE * buffer->pages;
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_size);
+
+static void
+rb_reset_cpu(struct ftrace_ring_buffer_per_cpu *cpu_buffer)
+{
+ rb_head_page_deactivate(cpu_buffer);
+
+ cpu_buffer->head_page
+ = list_entry(cpu_buffer->pages, struct buffer_page, list);
+ local_set(&cpu_buffer->head_page->write, 0);
+ local_set(&cpu_buffer->head_page->entries, 0);
+ local_set(&cpu_buffer->head_page->page->commit, 0);
+
+ cpu_buffer->head_page->read = 0;
+
+ cpu_buffer->tail_page = cpu_buffer->head_page;
+ cpu_buffer->commit_page = cpu_buffer->head_page;
+
+ INIT_LIST_HEAD(&cpu_buffer->reader_page->list);
+ local_set(&cpu_buffer->reader_page->write, 0);
+ local_set(&cpu_buffer->reader_page->entries, 0);
+ local_set(&cpu_buffer->reader_page->page->commit, 0);
+ cpu_buffer->reader_page->read = 0;
+
+ local_set(&cpu_buffer->commit_overrun, 0);
+ local_set(&cpu_buffer->overrun, 0);
+ local_set(&cpu_buffer->entries, 0);
+ local_set(&cpu_buffer->committing, 0);
+ local_set(&cpu_buffer->commits, 0);
+ cpu_buffer->read = 0;
+
+ cpu_buffer->write_stamp = 0;
+ cpu_buffer->read_stamp = 0;
+
+ cpu_buffer->lost_events = 0;
+ cpu_buffer->last_overrun = 0;
+
+ rb_head_page_activate(cpu_buffer);
+}
+
+/**
+ * ftrace_ring_buffer_reset_cpu - reset a ring buffer per CPU buffer
+ * @buffer: The ring buffer to reset a per cpu buffer of
+ * @cpu: The CPU buffer to be reset
+ */
+void ftrace_ring_buffer_reset_cpu(struct ftrace_ring_buffer *buffer, int cpu)
+{
+ struct ftrace_ring_buffer_per_cpu *cpu_buffer = buffer->buffers[cpu];
+ unsigned long flags;
+
+ if (!cpumask_test_cpu(cpu, buffer->cpumask))
+ return;
+
+ atomic_inc(&cpu_buffer->record_disabled);
+
+ spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+
+ if (RB_WARN_ON(cpu_buffer, local_read(&cpu_buffer->committing)))
+ goto out;
+
+ arch_spin_lock(&cpu_buffer->lock);
+
+ rb_reset_cpu(cpu_buffer);
+
+ arch_spin_unlock(&cpu_buffer->lock);
+
+ out:
+ spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+
+ atomic_dec(&cpu_buffer->record_disabled);
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_reset_cpu);
+
+/**
+ * ftrace_ring_buffer_reset - reset a ring buffer
+ * @buffer: The ring buffer to reset all cpu buffers
+ */
+void ftrace_ring_buffer_reset(struct ftrace_ring_buffer *buffer)
+{
+ int cpu;
+
+ for_each_buffer_cpu(buffer, cpu)
+ ftrace_ring_buffer_reset_cpu(buffer, cpu);
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_reset);
+
+/**
+ * rind_buffer_empty - is the ring buffer empty?
+ * @buffer: The ring buffer to test
+ */
+int ftrace_ring_buffer_empty(struct ftrace_ring_buffer *buffer)
+{
+ struct ftrace_ring_buffer_per_cpu *cpu_buffer;
+ unsigned long flags;
+ int dolock;
+ int cpu;
+ int ret;
+
+ dolock = rb_ok_to_lock();
+
+ /* yes this is racy, but if you don't like the race, lock the buffer */
+ for_each_buffer_cpu(buffer, cpu) {
+ cpu_buffer = buffer->buffers[cpu];
+ local_irq_save(flags);
+ if (dolock)
+ spin_lock(&cpu_buffer->reader_lock);
+ ret = rb_per_cpu_empty(cpu_buffer);
+ if (dolock)
+ spin_unlock(&cpu_buffer->reader_lock);
+ local_irq_restore(flags);
+
+ if (!ret)
+ return 0;
+ }
+
+ return 1;
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_empty);
+
+/**
+ * ftrace_ring_buffer_empty_cpu - is a cpu buffer of a ring buffer empty?
+ * @buffer: The ring buffer
+ * @cpu: The CPU buffer to test
+ */
+int ftrace_ring_buffer_empty_cpu(struct ftrace_ring_buffer *buffer, int cpu)
+{
+ struct ftrace_ring_buffer_per_cpu *cpu_buffer;
+ unsigned long flags;
+ int dolock;
+ int ret;
+
+ if (!cpumask_test_cpu(cpu, buffer->cpumask))
+ return 1;
+
+ dolock = rb_ok_to_lock();
+
+ cpu_buffer = buffer->buffers[cpu];
+ local_irq_save(flags);
+ if (dolock)
+ spin_lock(&cpu_buffer->reader_lock);
+ ret = rb_per_cpu_empty(cpu_buffer);
+ if (dolock)
+ spin_unlock(&cpu_buffer->reader_lock);
+ local_irq_restore(flags);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_empty_cpu);
+
+#ifdef CONFIG_FTRACE_RING_BUFFER_ALLOW_SWAP
+/**
+ * ftrace_ring_buffer_swap_cpu - swap a CPU buffer between two ring buffers
+ * @buffer_a: One buffer to swap with
+ * @buffer_b: The other buffer to swap with
+ *
+ * This function is useful for tracers that want to take a "snapshot"
+ * of a CPU buffer and has another back up buffer lying around.
+ * it is expected that the tracer handles the cpu buffer not being
+ * used at the moment.
+ */
+int ftrace_ring_buffer_swap_cpu(struct ftrace_ring_buffer *buffer_a,
+ struct ftrace_ring_buffer *buffer_b, int cpu)
+{
+ struct ftrace_ring_buffer_per_cpu *cpu_buffer_a;
+ struct ftrace_ring_buffer_per_cpu *cpu_buffer_b;
+ int ret = -EINVAL;
+
+ if (!cpumask_test_cpu(cpu, buffer_a->cpumask) ||
+ !cpumask_test_cpu(cpu, buffer_b->cpumask))
+ goto out;
+
+ /* At least make sure the two buffers are somewhat the same */
+ if (buffer_a->pages != buffer_b->pages)
+ goto out;
+
+ ret = -EAGAIN;
+
+ if (ftrace_ring_buffer_flags != RB_BUFFERS_ON)
+ goto out;
+
+ if (atomic_read(&buffer_a->record_disabled))
+ goto out;
+
+ if (atomic_read(&buffer_b->record_disabled))
+ goto out;
+
+ cpu_buffer_a = buffer_a->buffers[cpu];
+ cpu_buffer_b = buffer_b->buffers[cpu];
+
+ if (atomic_read(&cpu_buffer_a->record_disabled))
+ goto out;
+
+ if (atomic_read(&cpu_buffer_b->record_disabled))
+ goto out;
+
+ /*
+ * We can't do a synchronize_sched here because this
+ * function can be called in atomic context.
+ * Normally this will be called from the same CPU as cpu.
+ * If not it's up to the caller to protect this.
+ */
+ atomic_inc(&cpu_buffer_a->record_disabled);
+ atomic_inc(&cpu_buffer_b->record_disabled);
+
+ ret = -EBUSY;
+ if (local_read(&cpu_buffer_a->committing))
+ goto out_dec;
+ if (local_read(&cpu_buffer_b->committing))
+ goto out_dec;
+
+ buffer_a->buffers[cpu] = cpu_buffer_b;
+ buffer_b->buffers[cpu] = cpu_buffer_a;
+
+ cpu_buffer_b->buffer = buffer_a;
+ cpu_buffer_a->buffer = buffer_b;
+
+ ret = 0;
+
+out_dec:
+ atomic_dec(&cpu_buffer_a->record_disabled);
+ atomic_dec(&cpu_buffer_b->record_disabled);
+out:
+ return ret;
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_swap_cpu);
+#endif /* CONFIG_FTRACE_RING_BUFFER_ALLOW_SWAP */
+
+/**
+ * ftrace_ring_buffer_alloc_read_page - allocate a page to read from buffer
+ * @buffer: the buffer to allocate for.
+ *
+ * This function is used in conjunction with ftrace_ring_buffer_read_page.
+ * When reading a full page from the ring buffer, these functions
+ * can be used to speed up the process. The calling function should
+ * allocate a few pages first with this function. Then when it
+ * needs to get pages from the ring buffer, it passes the result
+ * of this function into ftrace_ring_buffer_read_page, which will swap
+ * the page that was allocated, with the read page of the buffer.
+ *
+ * Returns:
+ * The page allocated, or NULL on error.
+ */
+void *ftrace_ring_buffer_alloc_read_page(struct ftrace_ring_buffer *buffer)
+{
+ struct buffer_data_page *bpage;
+ unsigned long addr;
+
+ addr = __get_free_page(GFP_KERNEL);
+ if (!addr)
+ return NULL;
+
+ bpage = (void *)addr;
+
+ rb_init_page(bpage);
+
+ return bpage;
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_alloc_read_page);
+
+/**
+ * ftrace_ring_buffer_free_read_page - free an allocated read page
+ * @buffer: the buffer the page was allocate for
+ * @data: the page to free
+ *
+ * Free a page allocated from ftrace_ring_buffer_alloc_read_page.
+ */
+void ftrace_ring_buffer_free_read_page(struct ftrace_ring_buffer *buffer, void *data)
+{
+ free_page((unsigned long)data);
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_free_read_page);
+
+/**
+ * ftrace_ring_buffer_read_page - extract a page from the ring buffer
+ * @buffer: buffer to extract from
+ * @data_page: the page to use allocated from ftrace_ring_buffer_alloc_read_page
+ * @len: amount to extract
+ * @cpu: the cpu of the buffer to extract
+ * @full: should the extraction only happen when the page is full.
+ *
+ * This function will pull out a page from the ring buffer and consume it.
+ * @data_page must be the address of the variable that was returned
+ * from ftrace_ring_buffer_alloc_read_page. This is because the page might be used
+ * to swap with a page in the ring buffer.
+ *
+ * for example:
+ * rpage = ftrace_ring_buffer_alloc_read_page(buffer);
+ * if (!rpage)
+ * return error;
+ * ret = ftrace_ring_buffer_read_page(buffer, &rpage, len, cpu, 0);
+ * if (ret >= 0)
+ * process_page(rpage, ret);
+ *
+ * When @full is set, the function will not return true unless
+ * the writer is off the reader page.
+ *
+ * Note: it is up to the calling functions to handle sleeps and wakeups.
+ * The ring buffer can be used anywhere in the kernel and can not
+ * blindly call wake_up. The layer that uses the ring buffer must be
+ * responsible for that.
+ *
+ * Returns:
+ * >=0 if data has been transferred, returns the offset of consumed data.
+ * <0 if no data has been transferred.
+ */
+int ftrace_ring_buffer_read_page(struct ftrace_ring_buffer *buffer,
+ void **data_page, size_t len, int cpu, int full)
+{
+ struct ftrace_ring_buffer_per_cpu *cpu_buffer = buffer->buffers[cpu];
+ struct ftrace_ring_buffer_event *event;
+ struct buffer_data_page *bpage;
+ struct buffer_page *reader;
+ unsigned long missed_events;
+ unsigned long flags;
+ unsigned int commit;
+ unsigned int read;
+ u64 save_timestamp;
+ int ret = -1;
+
+ if (!cpumask_test_cpu(cpu, buffer->cpumask))
+ goto out;
+
+ /*
+ * If len is not big enough to hold the page header, then
+ * we can not copy anything.
+ */
+ if (len <= BUF_PAGE_HDR_SIZE)
+ goto out;
+
+ len -= BUF_PAGE_HDR_SIZE;
+
+ if (!data_page)
+ goto out;
+
+ bpage = *data_page;
+ if (!bpage)
+ goto out;
+
+ spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+
+ reader = rb_get_reader_page(cpu_buffer);
+ if (!reader)
+ goto out_unlock;
+
+ event = rb_reader_event(cpu_buffer);
+
+ read = reader->read;
+ commit = rb_page_commit(reader);
+
+ /* Check if any events were dropped */
+ missed_events = cpu_buffer->lost_events;
+
+ /*
+ * If this page has been partially read or
+ * if len is not big enough to read the rest of the page or
+ * a writer is still on the page, then
+ * we must copy the data from the page to the buffer.
+ * Otherwise, we can simply swap the page with the one passed in.
+ */
+ if (read || (len < (commit - read)) ||
+ cpu_buffer->reader_page == cpu_buffer->commit_page) {
+ struct buffer_data_page *rpage = cpu_buffer->reader_page->page;
+ unsigned int rpos = read;
+ unsigned int pos = 0;
+ unsigned int size;
+
+ if (full)
+ goto out_unlock;
+
+ if (len > (commit - read))
+ len = (commit - read);
+
+ size = rb_event_length(event);
+
+ if (len < size)
+ goto out_unlock;
+
+ /* save the current timestamp, since the user will need it */
+ save_timestamp = cpu_buffer->read_stamp;
+
+ /* Need to copy one event at a time */
+ do {
+ memcpy(bpage->data + pos, rpage->data + rpos, size);
+
+ len -= size;
+
+ rb_advance_reader(cpu_buffer);
+ rpos = reader->read;
+ pos += size;
+
+ event = rb_reader_event(cpu_buffer);
+ size = rb_event_length(event);
+ } while (len > size);
+
+ /* update bpage */
+ local_set(&bpage->commit, pos);
+ bpage->time_stamp = save_timestamp;
+
+ /* we copied everything to the beginning */
+ read = 0;
+ } else {
+ /* update the entry counter */
+ cpu_buffer->read += rb_page_entries(reader);
+
+ /* swap the pages */
+ rb_init_page(bpage);
+ bpage = reader->page;
+ reader->page = *data_page;
+ local_set(&reader->write, 0);
+ local_set(&reader->entries, 0);
+ reader->read = 0;
+ *data_page = bpage;
+
+ /*
+ * Use the real_end for the data size,
+ * This gives us a chance to store the lost events
+ * on the page.
+ */
+ if (reader->real_end)
+ local_set(&bpage->commit, reader->real_end);
+ }
+ ret = read;
+
+ cpu_buffer->lost_events = 0;
+
+ commit = local_read(&bpage->commit);
+ /*
+ * Set a flag in the commit field if we lost events
+ */
+ if (missed_events) {
+ /* If there is room at the end of the page to save the
+ * missed events, then record it there.
+ */
+ if (BUF_PAGE_SIZE - commit >= sizeof(missed_events)) {
+ memcpy(&bpage->data[commit], &missed_events,
+ sizeof(missed_events));
+ local_add(RB_MISSED_STORED, &bpage->commit);
+ commit += sizeof(missed_events);
+ }
+ local_add(RB_MISSED_EVENTS, &bpage->commit);
+ }
+
+ /*
+ * This page may be off to user land. Zero it out here.
+ */
+ if (commit < BUF_PAGE_SIZE)
+ memset(&bpage->data[commit], 0, BUF_PAGE_SIZE - commit);
+
+ out_unlock:
+ spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+
+ out:
+ return ret;
+}
+EXPORT_SYMBOL_GPL(ftrace_ring_buffer_read_page);
+
+#ifdef CONFIG_TRACING
+static ssize_t
+rb_simple_read(struct file *filp, char __user *ubuf,
+ size_t cnt, loff_t *ppos)
+{
+ unsigned long *p = filp->private_data;
+ char buf[64];
+ int r;
+
+ if (test_bit(RB_BUFFERS_DISABLED_BIT, p))
+ r = sprintf(buf, "permanently disabled\n");
+ else
+ r = sprintf(buf, "%d\n", test_bit(RB_BUFFERS_ON_BIT, p));
+
+ return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+}
+
+static ssize_t
+rb_simple_write(struct file *filp, const char __user *ubuf,
+ size_t cnt, loff_t *ppos)
+{
+ unsigned long *p = filp->private_data;
+ char buf[64];
+ unsigned long val;
+ int ret;
+
+ if (cnt >= sizeof(buf))
+ return -EINVAL;
+
+ if (copy_from_user(&buf, ubuf, cnt))
+ return -EFAULT;
+
+ buf[cnt] = 0;
+
+ ret = strict_strtoul(buf, 10, &val);
+ if (ret < 0)
+ return ret;
+
+ if (val)
+ set_bit(RB_BUFFERS_ON_BIT, p);
+ else
+ clear_bit(RB_BUFFERS_ON_BIT, p);
+
+ (*ppos)++;
+
+ return cnt;
+}
+
+static const struct file_operations rb_simple_fops = {
+ .open = tracing_open_generic,
+ .read = rb_simple_read,
+ .write = rb_simple_write,
+};
+
+
+static __init int rb_init_debugfs(void)
+{
+ struct dentry *d_tracer;
+
+ d_tracer = tracing_init_dentry();
+
+ trace_create_file("tracing_on", 0644, d_tracer,
+ &ftrace_ring_buffer_flags, &rb_simple_fops);
+
+ return 0;
+}
+
+fs_initcall(rb_init_debugfs);
+#endif
+
+#ifdef CONFIG_HOTPLUG_CPU
+static int rb_cpu_notify(struct notifier_block *self,
+ unsigned long action, void *hcpu)
+{
+ struct ftrace_ring_buffer *buffer =
+ container_of(self, struct ftrace_ring_buffer, cpu_notify);
+ long cpu = (long)hcpu;
+
+ switch (action) {
+ case CPU_UP_PREPARE:
+ case CPU_UP_PREPARE_FROZEN:
+ if (cpumask_test_cpu(cpu, buffer->cpumask))
+ return NOTIFY_OK;
+
+ buffer->buffers[cpu] =
+ rb_allocate_cpu_buffer(buffer, cpu);
+ if (!buffer->buffers[cpu]) {
+ WARN(1, "failed to allocate ring buffer on CPU %ld\n",
+ cpu);
+ return NOTIFY_OK;
+ }
+ smp_wmb();
+ cpumask_set_cpu(cpu, buffer->cpumask);
+ break;
+ case CPU_DOWN_PREPARE:
+ case CPU_DOWN_PREPARE_FROZEN:
+ /*
+ * Do nothing.
+ * If we were to free the buffer, then the user would
+ * lose any trace that was in the buffer.
+ */
+ break;
+ default:
+ break;
+ }
+ return NOTIFY_OK;
+}
+#endif
Index: linux.trees.git/kernel/trace/ring_buffer.c
===================================================================
--- linux.trees.git.orig/kernel/trace/ring_buffer.c 2010-07-09 18:08:14.000000000 -0400
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1,4022 +0,0 @@
-/*
- * Generic ring buffer
- *
- * Copyright (C) 2008 Steven Rostedt <srostedt@redhat.com>
- */
-#include <linux/ring_buffer.h>
-#include <linux/trace_clock.h>
-#include <linux/ftrace_irq.h>
-#include <linux/spinlock.h>
-#include <linux/debugfs.h>
-#include <linux/uaccess.h>
-#include <linux/hardirq.h>
-#include <linux/kmemcheck.h>
-#include <linux/module.h>
-#include <linux/percpu.h>
-#include <linux/mutex.h>
-#include <linux/slab.h>
-#include <linux/init.h>
-#include <linux/hash.h>
-#include <linux/list.h>
-#include <linux/cpu.h>
-#include <linux/fs.h>
-
-#include <asm/local.h>
-#include "trace.h"
-
-/*
- * The ring buffer header is special. We must manually up keep it.
- */
-int ring_buffer_print_entry_header(struct trace_seq *s)
-{
- int ret;
-
- ret = trace_seq_printf(s, "# compressed entry header\n");
- ret = trace_seq_printf(s, "\ttype_len : 5 bits\n");
- ret = trace_seq_printf(s, "\ttime_delta : 27 bits\n");
- ret = trace_seq_printf(s, "\tarray : 32 bits\n");
- ret = trace_seq_printf(s, "\n");
- ret = trace_seq_printf(s, "\tpadding : type == %d\n",
- RINGBUF_TYPE_PADDING);
- ret = trace_seq_printf(s, "\ttime_extend : type == %d\n",
- RINGBUF_TYPE_TIME_EXTEND);
- ret = trace_seq_printf(s, "\tdata max type_len == %d\n",
- RINGBUF_TYPE_DATA_TYPE_LEN_MAX);
-
- return ret;
-}
-
-/*
- * The ring buffer is made up of a list of pages. A separate list of pages is
- * allocated for each CPU. A writer may only write to a buffer that is
- * associated with the CPU it is currently executing on. A reader may read
- * from any per cpu buffer.
- *
- * The reader is special. For each per cpu buffer, the reader has its own
- * reader page. When a reader has read the entire reader page, this reader
- * page is swapped with another page in the ring buffer.
- *
- * Now, as long as the writer is off the reader page, the reader can do what
- * ever it wants with that page. The writer will never write to that page
- * again (as long as it is out of the ring buffer).
- *
- * Here's some silly ASCII art.
- *
- * +------+
- * |reader| RING BUFFER
- * |page |
- * +------+ +---+ +---+ +---+
- * | |-->| |-->| |
- * +---+ +---+ +---+
- * ^ |
- * | |
- * +---------------+
- *
- *
- * +------+
- * |reader| RING BUFFER
- * |page |------------------v
- * +------+ +---+ +---+ +---+
- * | |-->| |-->| |
- * +---+ +---+ +---+
- * ^ |
- * | |
- * +---------------+
- *
- *
- * +------+
- * |reader| RING BUFFER
- * |page |------------------v
- * +------+ +---+ +---+ +---+
- * ^ | |-->| |-->| |
- * | +---+ +---+ +---+
- * | |
- * | |
- * +------------------------------+
- *
- *
- * +------+
- * |buffer| RING BUFFER
- * |page |------------------v
- * +------+ +---+ +---+ +---+
- * ^ | | | |-->| |
- * | New +---+ +---+ +---+
- * | Reader------^ |
- * | page |
- * +------------------------------+
- *
- *
- * After we make this swap, the reader can hand this page off to the splice
- * code and be done with it. It can even allocate a new page if it needs to
- * and swap that into the ring buffer.
- *
- * We will be using cmpxchg soon to make all this lockless.
- *
- */
-
-/*
- * A fast way to enable or disable all ring buffers is to
- * call tracing_on or tracing_off. Turning off the ring buffers
- * prevents all ring buffers from being recorded to.
- * Turning this switch on, makes it OK to write to the
- * ring buffer, if the ring buffer is enabled itself.
- *
- * There's three layers that must be on in order to write
- * to the ring buffer.
- *
- * 1) This global flag must be set.
- * 2) The ring buffer must be enabled for recording.
- * 3) The per cpu buffer must be enabled for recording.
- *
- * In case of an anomaly, this global flag has a bit set that
- * will permantly disable all ring buffers.
- */
-
-/*
- * Global flag to disable all recording to ring buffers
- * This has two bits: ON, DISABLED
- *
- * ON DISABLED
- * ---- ----------
- * 0 0 : ring buffers are off
- * 1 0 : ring buffers are on
- * X 1 : ring buffers are permanently disabled
- */
-
-enum {
- RB_BUFFERS_ON_BIT = 0,
- RB_BUFFERS_DISABLED_BIT = 1,
-};
-
-enum {
- RB_BUFFERS_ON = 1 << RB_BUFFERS_ON_BIT,
- RB_BUFFERS_DISABLED = 1 << RB_BUFFERS_DISABLED_BIT,
-};
-
-static unsigned long ring_buffer_flags __read_mostly = RB_BUFFERS_ON;
-
-#define BUF_PAGE_HDR_SIZE offsetof(struct buffer_data_page, data)
-
-/**
- * tracing_on - enable all tracing buffers
- *
- * This function enables all tracing buffers that may have been
- * disabled with tracing_off.
- */
-void tracing_on(void)
-{
- set_bit(RB_BUFFERS_ON_BIT, &ring_buffer_flags);
-}
-EXPORT_SYMBOL_GPL(tracing_on);
-
-/**
- * tracing_off - turn off all tracing buffers
- *
- * This function stops all tracing buffers from recording data.
- * It does not disable any overhead the tracers themselves may
- * be causing. This function simply causes all recording to
- * the ring buffers to fail.
- */
-void tracing_off(void)
-{
- clear_bit(RB_BUFFERS_ON_BIT, &ring_buffer_flags);
-}
-EXPORT_SYMBOL_GPL(tracing_off);
-
-/**
- * tracing_off_permanent - permanently disable ring buffers
- *
- * This function, once called, will disable all ring buffers
- * permanently.
- */
-void tracing_off_permanent(void)
-{
- set_bit(RB_BUFFERS_DISABLED_BIT, &ring_buffer_flags);
-}
-
-/**
- * tracing_is_on - show state of ring buffers enabled
- */
-int tracing_is_on(void)
-{
- return ring_buffer_flags == RB_BUFFERS_ON;
-}
-EXPORT_SYMBOL_GPL(tracing_is_on);
-
-#define RB_EVNT_HDR_SIZE (offsetof(struct ring_buffer_event, array))
-#define RB_ALIGNMENT 4U
-#define RB_MAX_SMALL_DATA (RB_ALIGNMENT * RINGBUF_TYPE_DATA_TYPE_LEN_MAX)
-#define RB_EVNT_MIN_SIZE 8U /* two 32bit words */
-
-#if !defined(CONFIG_64BIT) || defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
-# define RB_FORCE_8BYTE_ALIGNMENT 0
-# define RB_ARCH_ALIGNMENT RB_ALIGNMENT
-#else
-# define RB_FORCE_8BYTE_ALIGNMENT 1
-# define RB_ARCH_ALIGNMENT 8U
-#endif
-
-/* define RINGBUF_TYPE_DATA for 'case RINGBUF_TYPE_DATA:' */
-#define RINGBUF_TYPE_DATA 0 ... RINGBUF_TYPE_DATA_TYPE_LEN_MAX
-
-enum {
- RB_LEN_TIME_EXTEND = 8,
- RB_LEN_TIME_STAMP = 16,
-};
-
-static inline int rb_null_event(struct ring_buffer_event *event)
-{
- return event->type_len == RINGBUF_TYPE_PADDING && !event->time_delta;
-}
-
-static void rb_event_set_padding(struct ring_buffer_event *event)
-{
- /* padding has a NULL time_delta */
- event->type_len = RINGBUF_TYPE_PADDING;
- event->time_delta = 0;
-}
-
-static unsigned
-rb_event_data_length(struct ring_buffer_event *event)
-{
- unsigned length;
-
- if (event->type_len)
- length = event->type_len * RB_ALIGNMENT;
- else
- length = event->array[0];
- return length + RB_EVNT_HDR_SIZE;
-}
-
-/* inline for ring buffer fast paths */
-static unsigned
-rb_event_length(struct ring_buffer_event *event)
-{
- switch (event->type_len) {
- case RINGBUF_TYPE_PADDING:
- if (rb_null_event(event))
- /* undefined */
- return -1;
- return event->array[0] + RB_EVNT_HDR_SIZE;
-
- case RINGBUF_TYPE_TIME_EXTEND:
- return RB_LEN_TIME_EXTEND;
-
- case RINGBUF_TYPE_TIME_STAMP:
- return RB_LEN_TIME_STAMP;
-
- case RINGBUF_TYPE_DATA:
- return rb_event_data_length(event);
- default:
- BUG();
- }
- /* not hit */
- return 0;
-}
-
-/**
- * ring_buffer_event_length - return the length of the event
- * @event: the event to get the length of
- */
-unsigned ring_buffer_event_length(struct ring_buffer_event *event)
-{
- unsigned length = rb_event_length(event);
- if (event->type_len > RINGBUF_TYPE_DATA_TYPE_LEN_MAX)
- return length;
- length -= RB_EVNT_HDR_SIZE;
- if (length > RB_MAX_SMALL_DATA + sizeof(event->array[0]))
- length -= sizeof(event->array[0]);
- return length;
-}
-EXPORT_SYMBOL_GPL(ring_buffer_event_length);
-
-/* inline for ring buffer fast paths */
-static void *
-rb_event_data(struct ring_buffer_event *event)
-{
- BUG_ON(event->type_len > RINGBUF_TYPE_DATA_TYPE_LEN_MAX);
- /* If length is in len field, then array[0] has the data */
- if (event->type_len)
- return (void *)&event->array[0];
- /* Otherwise length is in array[0] and array[1] has the data */
- return (void *)&event->array[1];
-}
-
-/**
- * ring_buffer_event_data - return the data of the event
- * @event: the event to get the data from
- */
-void *ring_buffer_event_data(struct ring_buffer_event *event)
-{
- return rb_event_data(event);
-}
-EXPORT_SYMBOL_GPL(ring_buffer_event_data);
-
-#define for_each_buffer_cpu(buffer, cpu) \
- for_each_cpu(cpu, buffer->cpumask)
-
-#define TS_SHIFT 27
-#define TS_MASK ((1ULL << TS_SHIFT) - 1)
-#define TS_DELTA_TEST (~TS_MASK)
-
-/* Flag when events were overwritten */
-#define RB_MISSED_EVENTS (1 << 31)
-/* Missed count stored at end */
-#define RB_MISSED_STORED (1 << 30)
-
-struct buffer_data_page {
- u64 time_stamp; /* page time stamp */
- local_t commit; /* write committed index */
- unsigned char data[]; /* data of buffer page */
-};
-
-/*
- * Note, the buffer_page list must be first. The buffer pages
- * are allocated in cache lines, which means that each buffer
- * page will be at the beginning of a cache line, and thus
- * the least significant bits will be zero. We use this to
- * add flags in the list struct pointers, to make the ring buffer
- * lockless.
- */
-struct buffer_page {
- struct list_head list; /* list of buffer pages */
- local_t write; /* index for next write */
- unsigned read; /* index for next read */
- local_t entries; /* entries on this page */
- unsigned long real_end; /* real end of data */
- struct buffer_data_page *page; /* Actual data page */
-};
-
-/*
- * The buffer page counters, write and entries, must be reset
- * atomically when crossing page boundaries. To synchronize this
- * update, two counters are inserted into the number. One is
- * the actual counter for the write position or count on the page.
- *
- * The other is a counter of updaters. Before an update happens
- * the update partition of the counter is incremented. This will
- * allow the updater to update the counter atomically.
- *
- * The counter is 20 bits, and the state data is 12.
- */
-#define RB_WRITE_MASK 0xfffff
-#define RB_WRITE_INTCNT (1 << 20)
-
-static void rb_init_page(struct buffer_data_page *bpage)
-{
- local_set(&bpage->commit, 0);
-}
-
-/**
- * ring_buffer_page_len - the size of data on the page.
- * @page: The page to read
- *
- * Returns the amount of data on the page, including buffer page header.
- */
-size_t ring_buffer_page_len(void *page)
-{
- return local_read(&((struct buffer_data_page *)page)->commit)
- + BUF_PAGE_HDR_SIZE;
-}
-
-/*
- * Also stolen from mm/slob.c. Thanks to Mathieu Desnoyers for pointing
- * this issue out.
- */
-static void free_buffer_page(struct buffer_page *bpage)
-{
- free_page((unsigned long)bpage->page);
- kfree(bpage);
-}
-
-/*
- * We need to fit the time_stamp delta into 27 bits.
- */
-static inline int test_time_stamp(u64 delta)
-{
- if (delta & TS_DELTA_TEST)
- return 1;
- return 0;
-}
-
-#define BUF_PAGE_SIZE (PAGE_SIZE - BUF_PAGE_HDR_SIZE)
-
-/* Max payload is BUF_PAGE_SIZE - header (8bytes) */
-#define BUF_MAX_DATA_SIZE (BUF_PAGE_SIZE - (sizeof(u32) * 2))
-
-/* Max number of timestamps that can fit on a page */
-#define RB_TIMESTAMPS_PER_PAGE (BUF_PAGE_SIZE / RB_LEN_TIME_STAMP)
-
-int ring_buffer_print_page_header(struct trace_seq *s)
-{
- struct buffer_data_page field;
- int ret;
-
- ret = trace_seq_printf(s, "\tfield: u64 timestamp;\t"
- "offset:0;\tsize:%u;\tsigned:%u;\n",
- (unsigned int)sizeof(field.time_stamp),
- (unsigned int)is_signed_type(u64));
-
- ret = trace_seq_printf(s, "\tfield: local_t commit;\t"
- "offset:%u;\tsize:%u;\tsigned:%u;\n",
- (unsigned int)offsetof(typeof(field), commit),
- (unsigned int)sizeof(field.commit),
- (unsigned int)is_signed_type(long));
-
- ret = trace_seq_printf(s, "\tfield: int overwrite;\t"
- "offset:%u;\tsize:%u;\tsigned:%u;\n",
- (unsigned int)offsetof(typeof(field), commit),
- 1,
- (unsigned int)is_signed_type(long));
-
- ret = trace_seq_printf(s, "\tfield: char data;\t"
- "offset:%u;\tsize:%u;\tsigned:%u;\n",
- (unsigned int)offsetof(typeof(field), data),
- (unsigned int)BUF_PAGE_SIZE,
- (unsigned int)is_signed_type(char));
-
- return ret;
-}
-
-/*
- * head_page == tail_page && head == tail then buffer is empty.
- */
-struct ring_buffer_per_cpu {
- int cpu;
- struct ring_buffer *buffer;
- spinlock_t reader_lock; /* serialize readers */
- arch_spinlock_t lock;
- struct lock_class_key lock_key;
- struct list_head *pages;
- struct buffer_page *head_page; /* read from head */
- struct buffer_page *tail_page; /* write to tail */
- struct buffer_page *commit_page; /* committed pages */
- struct buffer_page *reader_page;
- unsigned long lost_events;
- unsigned long last_overrun;
- local_t commit_overrun;
- local_t overrun;
- local_t entries;
- local_t committing;
- local_t commits;
- unsigned long read;
- u64 write_stamp;
- u64 read_stamp;
- atomic_t record_disabled;
-};
-
-struct ring_buffer {
- unsigned pages;
- unsigned flags;
- int cpus;
- atomic_t record_disabled;
- cpumask_var_t cpumask;
-
- struct lock_class_key *reader_lock_key;
-
- struct mutex mutex;
-
- struct ring_buffer_per_cpu **buffers;
-
-#ifdef CONFIG_HOTPLUG_CPU
- struct notifier_block cpu_notify;
-#endif
- u64 (*clock)(void);
-};
-
-struct ring_buffer_iter {
- struct ring_buffer_per_cpu *cpu_buffer;
- unsigned long head;
- struct buffer_page *head_page;
- struct buffer_page *cache_reader_page;
- unsigned long cache_read;
- u64 read_stamp;
-};
-
-/* buffer may be either ring_buffer or ring_buffer_per_cpu */
-#define RB_WARN_ON(b, cond) \
- ({ \
- int _____ret = unlikely(cond); \
- if (_____ret) { \
- if (__same_type(*(b), struct ring_buffer_per_cpu)) { \
- struct ring_buffer_per_cpu *__b = \
- (void *)b; \
- atomic_inc(&__b->buffer->record_disabled); \
- } else \
- atomic_inc(&b->record_disabled); \
- WARN_ON(1); \
- } \
- _____ret; \
- })
-
-/* Up this if you want to test the TIME_EXTENTS and normalization */
-#define DEBUG_SHIFT 0
-
-static inline u64 rb_time_stamp(struct ring_buffer *buffer)
-{
- /* shift to debug/test normalization and TIME_EXTENTS */
- return buffer->clock() << DEBUG_SHIFT;
-}
-
-u64 ring_buffer_time_stamp(struct ring_buffer *buffer, int cpu)
-{
- u64 time;
-
- preempt_disable_notrace();
- time = rb_time_stamp(buffer);
- preempt_enable_no_resched_notrace();
-
- return time;
-}
-EXPORT_SYMBOL_GPL(ring_buffer_time_stamp);
-
-void ring_buffer_normalize_time_stamp(struct ring_buffer *buffer,
- int cpu, u64 *ts)
-{
- /* Just stupid testing the normalize function and deltas */
- *ts >>= DEBUG_SHIFT;
-}
-EXPORT_SYMBOL_GPL(ring_buffer_normalize_time_stamp);
-
-/*
- * Making the ring buffer lockless makes things tricky.
- * Although writes only happen on the CPU that they are on,
- * and they only need to worry about interrupts. Reads can
- * happen on any CPU.
- *
- * The reader page is always off the ring buffer, but when the
- * reader finishes with a page, it needs to swap its page with
- * a new one from the buffer. The reader needs to take from
- * the head (writes go to the tail). But if a writer is in overwrite
- * mode and wraps, it must push the head page forward.
- *
- * Here lies the problem.
- *
- * The reader must be careful to replace only the head page, and
- * not another one. As described at the top of the file in the
- * ASCII art, the reader sets its old page to point to the next
- * page after head. It then sets the page after head to point to
- * the old reader page. But if the writer moves the head page
- * during this operation, the reader could end up with the tail.
- *
- * We use cmpxchg to help prevent this race. We also do something
- * special with the page before head. We set the LSB to 1.
- *
- * When the writer must push the page forward, it will clear the
- * bit that points to the head page, move the head, and then set
- * the bit that points to the new head page.
- *
- * We also don't want an interrupt coming in and moving the head
- * page on another writer. Thus we use the second LSB to catch
- * that too. Thus:
- *
- * head->list->prev->next bit 1 bit 0
- * ------- -------
- * Normal page 0 0
- * Points to head page 0 1
- * New head page 1 0
- *
- * Note we can not trust the prev pointer of the head page, because:
- *
- * +----+ +-----+ +-----+
- * | |------>| T |---X--->| N |
- * | |<------| | | |
- * +----+ +-----+ +-----+
- * ^ ^ |
- * | +-----+ | |
- * +----------| R |----------+ |
- * | |<-----------+
- * +-----+
- *
- * Key: ---X--> HEAD flag set in pointer
- * T Tail page
- * R Reader page
- * N Next page
- *
- * (see __rb_reserve_next() to see where this happens)
- *
- * What the above shows is that the reader just swapped out
- * the reader page with a page in the buffer, but before it
- * could make the new header point back to the new page added
- * it was preempted by a writer. The writer moved forward onto
- * the new page added by the reader and is about to move forward
- * again.
- *
- * You can see, it is legitimate for the previous pointer of
- * the head (or any page) not to point back to itself. But only
- * temporarially.
- */
-
-#define RB_PAGE_NORMAL 0UL
-#define RB_PAGE_HEAD 1UL
-#define RB_PAGE_UPDATE 2UL
-
-
-#define RB_FLAG_MASK 3UL
-
-/* PAGE_MOVED is not part of the mask */
-#define RB_PAGE_MOVED 4UL
-
-/*
- * rb_list_head - remove any bit
- */
-static struct list_head *rb_list_head(struct list_head *list)
-{
- unsigned long val = (unsigned long)list;
-
- return (struct list_head *)(val & ~RB_FLAG_MASK);
-}
-
-/*
- * rb_is_head_page - test if the given page is the head page
- *
- * Because the reader may move the head_page pointer, we can
- * not trust what the head page is (it may be pointing to
- * the reader page). But if the next page is a header page,
- * its flags will be non zero.
- */
-static int inline
-rb_is_head_page(struct ring_buffer_per_cpu *cpu_buffer,
- struct buffer_page *page, struct list_head *list)
-{
- unsigned long val;
-
- val = (unsigned long)list->next;
-
- if ((val & ~RB_FLAG_MASK) != (unsigned long)&page->list)
- return RB_PAGE_MOVED;
-
- return val & RB_FLAG_MASK;
-}
-
-/*
- * rb_is_reader_page
- *
- * The unique thing about the reader page, is that, if the
- * writer is ever on it, the previous pointer never points
- * back to the reader page.
- */
-static int rb_is_reader_page(struct buffer_page *page)
-{
- struct list_head *list = page->list.prev;
-
- return rb_list_head(list->next) != &page->list;
-}
-
-/*
- * rb_set_list_to_head - set a list_head to be pointing to head.
- */
-static void rb_set_list_to_head(struct ring_buffer_per_cpu *cpu_buffer,
- struct list_head *list)
-{
- unsigned long *ptr;
-
- ptr = (unsigned long *)&list->next;
- *ptr |= RB_PAGE_HEAD;
- *ptr &= ~RB_PAGE_UPDATE;
-}
-
-/*
- * rb_head_page_activate - sets up head page
- */
-static void rb_head_page_activate(struct ring_buffer_per_cpu *cpu_buffer)
-{
- struct buffer_page *head;
-
- head = cpu_buffer->head_page;
- if (!head)
- return;
-
- /*
- * Set the previous list pointer to have the HEAD flag.
- */
- rb_set_list_to_head(cpu_buffer, head->list.prev);
-}
-
-static void rb_list_head_clear(struct list_head *list)
-{
- unsigned long *ptr = (unsigned long *)&list->next;
-
- *ptr &= ~RB_FLAG_MASK;
-}
-
-/*
- * rb_head_page_dactivate - clears head page ptr (for free list)
- */
-static void
-rb_head_page_deactivate(struct ring_buffer_per_cpu *cpu_buffer)
-{
- struct list_head *hd;
-
- /* Go through the whole list and clear any pointers found. */
- rb_list_head_clear(cpu_buffer->pages);
-
- list_for_each(hd, cpu_buffer->pages)
- rb_list_head_clear(hd);
-}
-
-static int rb_head_page_set(struct ring_buffer_per_cpu *cpu_buffer,
- struct buffer_page *head,
- struct buffer_page *prev,
- int old_flag, int new_flag)
-{
- struct list_head *list;
- unsigned long val = (unsigned long)&head->list;
- unsigned long ret;
-
- list = &prev->list;
-
- val &= ~RB_FLAG_MASK;
-
- ret = cmpxchg((unsigned long *)&list->next,
- val | old_flag, val | new_flag);
-
- /* check if the reader took the page */
- if ((ret & ~RB_FLAG_MASK) != val)
- return RB_PAGE_MOVED;
-
- return ret & RB_FLAG_MASK;
-}
-
-static int rb_head_page_set_update(struct ring_buffer_per_cpu *cpu_buffer,
- struct buffer_page *head,
- struct buffer_page *prev,
- int old_flag)
-{
- return rb_head_page_set(cpu_buffer, head, prev,
- old_flag, RB_PAGE_UPDATE);
-}
-
-static int rb_head_page_set_head(struct ring_buffer_per_cpu *cpu_buffer,
- struct buffer_page *head,
- struct buffer_page *prev,
- int old_flag)
-{
- return rb_head_page_set(cpu_buffer, head, prev,
- old_flag, RB_PAGE_HEAD);
-}
-
-static int rb_head_page_set_normal(struct ring_buffer_per_cpu *cpu_buffer,
- struct buffer_page *head,
- struct buffer_page *prev,
- int old_flag)
-{
- return rb_head_page_set(cpu_buffer, head, prev,
- old_flag, RB_PAGE_NORMAL);
-}
-
-static inline void rb_inc_page(struct ring_buffer_per_cpu *cpu_buffer,
- struct buffer_page **bpage)
-{
- struct list_head *p = rb_list_head((*bpage)->list.next);
-
- *bpage = list_entry(p, struct buffer_page, list);
-}
-
-static struct buffer_page *
-rb_set_head_page(struct ring_buffer_per_cpu *cpu_buffer)
-{
- struct buffer_page *head;
- struct buffer_page *page;
- struct list_head *list;
- int i;
-
- if (RB_WARN_ON(cpu_buffer, !cpu_buffer->head_page))
- return NULL;
-
- /* sanity check */
- list = cpu_buffer->pages;
- if (RB_WARN_ON(cpu_buffer, rb_list_head(list->prev->next) != list))
- return NULL;
-
- page = head = cpu_buffer->head_page;
- /*
- * It is possible that the writer moves the header behind
- * where we started, and we miss in one loop.
- * A second loop should grab the header, but we'll do
- * three loops just because I'm paranoid.
- */
- for (i = 0; i < 3; i++) {
- do {
- if (rb_is_head_page(cpu_buffer, page, page->list.prev)) {
- cpu_buffer->head_page = page;
- return page;
- }
- rb_inc_page(cpu_buffer, &page);
- } while (page != head);
- }
-
- RB_WARN_ON(cpu_buffer, 1);
-
- return NULL;
-}
-
-static int rb_head_page_replace(struct buffer_page *old,
- struct buffer_page *new)
-{
- unsigned long *ptr = (unsigned long *)&old->list.prev->next;
- unsigned long val;
- unsigned long ret;
-
- val = *ptr & ~RB_FLAG_MASK;
- val |= RB_PAGE_HEAD;
-
- ret = cmpxchg(ptr, val, (unsigned long)&new->list);
-
- return ret == val;
-}
-
-/*
- * rb_tail_page_update - move the tail page forward
- *
- * Returns 1 if moved tail page, 0 if someone else did.
- */
-static int rb_tail_page_update(struct ring_buffer_per_cpu *cpu_buffer,
- struct buffer_page *tail_page,
- struct buffer_page *next_page)
-{
- struct buffer_page *old_tail;
- unsigned long old_entries;
- unsigned long old_write;
- int ret = 0;
-
- /*
- * The tail page now needs to be moved forward.
- *
- * We need to reset the tail page, but without messing
- * with possible erasing of data brought in by interrupts
- * that have moved the tail page and are currently on it.
- *
- * We add a counter to the write field to denote this.
- */
- old_write = local_add_return(RB_WRITE_INTCNT, &next_page->write);
- old_entries = local_add_return(RB_WRITE_INTCNT, &next_page->entries);
-
- /*
- * Just make sure we have seen our old_write and synchronize
- * with any interrupts that come in.
- */
- barrier();
-
- /*
- * If the tail page is still the same as what we think
- * it is, then it is up to us to update the tail
- * pointer.
- */
- if (tail_page == cpu_buffer->tail_page) {
- /* Zero the write counter */
- unsigned long val = old_write & ~RB_WRITE_MASK;
- unsigned long eval = old_entries & ~RB_WRITE_MASK;
-
- /*
- * This will only succeed if an interrupt did
- * not come in and change it. In which case, we
- * do not want to modify it.
- *
- * We add (void) to let the compiler know that we do not care
- * about the return value of these functions. We use the
- * cmpxchg to only update if an interrupt did not already
- * do it for us. If the cmpxchg fails, we don't care.
- */
- (void)local_cmpxchg(&next_page->write, old_write, val);
- (void)local_cmpxchg(&next_page->entries, old_entries, eval);
-
- /*
- * No need to worry about races with clearing out the commit.
- * it only can increment when a commit takes place. But that
- * only happens in the outer most nested commit.
- */
- local_set(&next_page->page->commit, 0);
-
- old_tail = cmpxchg(&cpu_buffer->tail_page,
- tail_page, next_page);
-
- if (old_tail == tail_page)
- ret = 1;
- }
-
- return ret;
-}
-
-static int rb_check_bpage(struct ring_buffer_per_cpu *cpu_buffer,
- struct buffer_page *bpage)
-{
- unsigned long val = (unsigned long)bpage;
-
- if (RB_WARN_ON(cpu_buffer, val & RB_FLAG_MASK))
- return 1;
-
- return 0;
-}
-
-/**
- * rb_check_list - make sure a pointer to a list has the last bits zero
- */
-static int rb_check_list(struct ring_buffer_per_cpu *cpu_buffer,
- struct list_head *list)
-{
- if (RB_WARN_ON(cpu_buffer, rb_list_head(list->prev) != list->prev))
- return 1;
- if (RB_WARN_ON(cpu_buffer, rb_list_head(list->next) != list->next))
- return 1;
- return 0;
-}
-
-/**
- * check_pages - integrity check of buffer pages
- * @cpu_buffer: CPU buffer with pages to test
- *
- * As a safety measure we check to make sure the data pages have not
- * been corrupted.
- */
-static int rb_check_pages(struct ring_buffer_per_cpu *cpu_buffer)
-{
- struct list_head *head = cpu_buffer->pages;
- struct buffer_page *bpage, *tmp;
-
- rb_head_page_deactivate(cpu_buffer);
-
- if (RB_WARN_ON(cpu_buffer, head->next->prev != head))
- return -1;
- if (RB_WARN_ON(cpu_buffer, head->prev->next != head))
- return -1;
-
- if (rb_check_list(cpu_buffer, head))
- return -1;
-
- list_for_each_entry_safe(bpage, tmp, head, list) {
- if (RB_WARN_ON(cpu_buffer,
- bpage->list.next->prev != &bpage->list))
- return -1;
- if (RB_WARN_ON(cpu_buffer,
- bpage->list.prev->next != &bpage->list))
- return -1;
- if (rb_check_list(cpu_buffer, &bpage->list))
- return -1;
- }
-
- rb_head_page_activate(cpu_buffer);
-
- return 0;
-}
-
-static int rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer,
- unsigned nr_pages)
-{
- struct buffer_page *bpage, *tmp;
- unsigned long addr;
- LIST_HEAD(pages);
- unsigned i;
-
- WARN_ON(!nr_pages);
-
- for (i = 0; i < nr_pages; i++) {
- bpage = kzalloc_node(ALIGN(sizeof(*bpage), cache_line_size()),
- GFP_KERNEL, cpu_to_node(cpu_buffer->cpu));
- if (!bpage)
- goto free_pages;
-
- rb_check_bpage(cpu_buffer, bpage);
-
- list_add(&bpage->list, &pages);
-
- addr = __get_free_page(GFP_KERNEL);
- if (!addr)
- goto free_pages;
- bpage->page = (void *)addr;
- rb_init_page(bpage->page);
- }
-
- /*
- * The ring buffer page list is a circular list that does not
- * start and end with a list head. All page list items point to
- * other pages.
- */
- cpu_buffer->pages = pages.next;
- list_del(&pages);
-
- rb_check_pages(cpu_buffer);
-
- return 0;
-
- free_pages:
- list_for_each_entry_safe(bpage, tmp, &pages, list) {
- list_del_init(&bpage->list);
- free_buffer_page(bpage);
- }
- return -ENOMEM;
-}
-
-static struct ring_buffer_per_cpu *
-rb_allocate_cpu_buffer(struct ring_buffer *buffer, int cpu)
-{
- struct ring_buffer_per_cpu *cpu_buffer;
- struct buffer_page *bpage;
- unsigned long addr;
- int ret;
-
- cpu_buffer = kzalloc_node(ALIGN(sizeof(*cpu_buffer), cache_line_size()),
- GFP_KERNEL, cpu_to_node(cpu));
- if (!cpu_buffer)
- return NULL;
-
- cpu_buffer->cpu = cpu;
- cpu_buffer->buffer = buffer;
- spin_lock_init(&cpu_buffer->reader_lock);
- lockdep_set_class(&cpu_buffer->reader_lock, buffer->reader_lock_key);
- cpu_buffer->lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
-
- bpage = kzalloc_node(ALIGN(sizeof(*bpage), cache_line_size()),
- GFP_KERNEL, cpu_to_node(cpu));
- if (!bpage)
- goto fail_free_buffer;
-
- rb_check_bpage(cpu_buffer, bpage);
-
- cpu_buffer->reader_page = bpage;
- addr = __get_free_page(GFP_KERNEL);
- if (!addr)
- goto fail_free_reader;
- bpage->page = (void *)addr;
- rb_init_page(bpage->page);
-
- INIT_LIST_HEAD(&cpu_buffer->reader_page->list);
-
- ret = rb_allocate_pages(cpu_buffer, buffer->pages);
- if (ret < 0)
- goto fail_free_reader;
-
- cpu_buffer->head_page
- = list_entry(cpu_buffer->pages, struct buffer_page, list);
- cpu_buffer->tail_page = cpu_buffer->commit_page = cpu_buffer->head_page;
-
- rb_head_page_activate(cpu_buffer);
-
- return cpu_buffer;
-
- fail_free_reader:
- free_buffer_page(cpu_buffer->reader_page);
-
- fail_free_buffer:
- kfree(cpu_buffer);
- return NULL;
-}
-
-static void rb_free_cpu_buffer(struct ring_buffer_per_cpu *cpu_buffer)
-{
- struct list_head *head = cpu_buffer->pages;
- struct buffer_page *bpage, *tmp;
-
- free_buffer_page(cpu_buffer->reader_page);
-
- rb_head_page_deactivate(cpu_buffer);
-
- if (head) {
- list_for_each_entry_safe(bpage, tmp, head, list) {
- list_del_init(&bpage->list);
- free_buffer_page(bpage);
- }
- bpage = list_entry(head, struct buffer_page, list);
- free_buffer_page(bpage);
- }
-
- kfree(cpu_buffer);
-}
-
-#ifdef CONFIG_HOTPLUG_CPU
-static int rb_cpu_notify(struct notifier_block *self,
- unsigned long action, void *hcpu);
-#endif
-
-/**
- * ring_buffer_alloc - allocate a new ring_buffer
- * @size: the size in bytes per cpu that is needed.
- * @flags: attributes to set for the ring buffer.
- *
- * Currently the only flag that is available is the RB_FL_OVERWRITE
- * flag. This flag means that the buffer will overwrite old data
- * when the buffer wraps. If this flag is not set, the buffer will
- * drop data when the tail hits the head.
- */
-struct ring_buffer *__ring_buffer_alloc(unsigned long size, unsigned flags,
- struct lock_class_key *key)
-{
- struct ring_buffer *buffer;
- int bsize;
- int cpu;
-
- /* keep it in its own cache line */
- buffer = kzalloc(ALIGN(sizeof(*buffer), cache_line_size()),
- GFP_KERNEL);
- if (!buffer)
- return NULL;
-
- if (!alloc_cpumask_var(&buffer->cpumask, GFP_KERNEL))
- goto fail_free_buffer;
-
- buffer->pages = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
- buffer->flags = flags;
- buffer->clock = trace_clock_local;
- buffer->reader_lock_key = key;
-
- /* need at least two pages */
- if (buffer->pages < 2)
- buffer->pages = 2;
-
- /*
- * In case of non-hotplug cpu, if the ring-buffer is allocated
- * in early initcall, it will not be notified of secondary cpus.
- * In that off case, we need to allocate for all possible cpus.
- */
-#ifdef CONFIG_HOTPLUG_CPU
- get_online_cpus();
- cpumask_copy(buffer->cpumask, cpu_online_mask);
-#else
- cpumask_copy(buffer->cpumask, cpu_possible_mask);
-#endif
- buffer->cpus = nr_cpu_ids;
-
- bsize = sizeof(void *) * nr_cpu_ids;
- buffer->buffers = kzalloc(ALIGN(bsize, cache_line_size()),
- GFP_KERNEL);
- if (!buffer->buffers)
- goto fail_free_cpumask;
-
- for_each_buffer_cpu(buffer, cpu) {
- buffer->buffers[cpu] =
- rb_allocate_cpu_buffer(buffer, cpu);
- if (!buffer->buffers[cpu])
- goto fail_free_buffers;
- }
-
-#ifdef CONFIG_HOTPLUG_CPU
- buffer->cpu_notify.notifier_call = rb_cpu_notify;
- buffer->cpu_notify.priority = 0;
- register_cpu_notifier(&buffer->cpu_notify);
-#endif
-
- put_online_cpus();
- mutex_init(&buffer->mutex);
-
- return buffer;
-
- fail_free_buffers:
- for_each_buffer_cpu(buffer, cpu) {
- if (buffer->buffers[cpu])
- rb_free_cpu_buffer(buffer->buffers[cpu]);
- }
- kfree(buffer->buffers);
-
- fail_free_cpumask:
- free_cpumask_var(buffer->cpumask);
- put_online_cpus();
-
- fail_free_buffer:
- kfree(buffer);
- return NULL;
-}
-EXPORT_SYMBOL_GPL(__ring_buffer_alloc);
-
-/**
- * ring_buffer_free - free a ring buffer.
- * @buffer: the buffer to free.
- */
-void
-ring_buffer_free(struct ring_buffer *buffer)
-{
- int cpu;
-
- get_online_cpus();
-
-#ifdef CONFIG_HOTPLUG_CPU
- unregister_cpu_notifier(&buffer->cpu_notify);
-#endif
-
- for_each_buffer_cpu(buffer, cpu)
- rb_free_cpu_buffer(buffer->buffers[cpu]);
-
- put_online_cpus();
-
- kfree(buffer->buffers);
- free_cpumask_var(buffer->cpumask);
-
- kfree(buffer);
-}
-EXPORT_SYMBOL_GPL(ring_buffer_free);
-
-void ring_buffer_set_clock(struct ring_buffer *buffer,
- u64 (*clock)(void))
-{
- buffer->clock = clock;
-}
-
-static void rb_reset_cpu(struct ring_buffer_per_cpu *cpu_buffer);
-
-static void
-rb_remove_pages(struct ring_buffer_per_cpu *cpu_buffer, unsigned nr_pages)
-{
- struct buffer_page *bpage;
- struct list_head *p;
- unsigned i;
-
- spin_lock_irq(&cpu_buffer->reader_lock);
- rb_head_page_deactivate(cpu_buffer);
-
- for (i = 0; i < nr_pages; i++) {
- if (RB_WARN_ON(cpu_buffer, list_empty(cpu_buffer->pages)))
- goto out;
- p = cpu_buffer->pages->next;
- bpage = list_entry(p, struct buffer_page, list);
- list_del_init(&bpage->list);
- free_buffer_page(bpage);
- }
- if (RB_WARN_ON(cpu_buffer, list_empty(cpu_buffer->pages)))
- goto out;
-
- rb_reset_cpu(cpu_buffer);
- rb_check_pages(cpu_buffer);
-
-out:
- spin_unlock_irq(&cpu_buffer->reader_lock);
-}
-
-static void
-rb_insert_pages(struct ring_buffer_per_cpu *cpu_buffer,
- struct list_head *pages, unsigned nr_pages)
-{
- struct buffer_page *bpage;
- struct list_head *p;
- unsigned i;
-
- spin_lock_irq(&cpu_buffer->reader_lock);
- rb_head_page_deactivate(cpu_buffer);
-
- for (i = 0; i < nr_pages; i++) {
- if (RB_WARN_ON(cpu_buffer, list_empty(pages)))
- goto out;
- p = pages->next;
- bpage = list_entry(p, struct buffer_page, list);
- list_del_init(&bpage->list);
- list_add_tail(&bpage->list, cpu_buffer->pages);
- }
- rb_reset_cpu(cpu_buffer);
- rb_check_pages(cpu_buffer);
-
-out:
- spin_unlock_irq(&cpu_buffer->reader_lock);
-}
-
-/**
- * ring_buffer_resize - resize the ring buffer
- * @buffer: the buffer to resize.
- * @size: the new size.
- *
- * Minimum size is 2 * BUF_PAGE_SIZE.
- *
- * Returns -1 on failure.
- */
-int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size)
-{
- struct ring_buffer_per_cpu *cpu_buffer;
- unsigned nr_pages, rm_pages, new_pages;
- struct buffer_page *bpage, *tmp;
- unsigned long buffer_size;
- unsigned long addr;
- LIST_HEAD(pages);
- int i, cpu;
-
- /*
- * Always succeed at resizing a non-existent buffer:
- */
- if (!buffer)
- return size;
-
- size = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
- size *= BUF_PAGE_SIZE;
- buffer_size = buffer->pages * BUF_PAGE_SIZE;
-
- /* we need a minimum of two pages */
- if (size < BUF_PAGE_SIZE * 2)
- size = BUF_PAGE_SIZE * 2;
-
- if (size == buffer_size)
- return size;
-
- atomic_inc(&buffer->record_disabled);
-
- /* Make sure all writers are done with this buffer. */
- synchronize_sched();
-
- mutex_lock(&buffer->mutex);
- get_online_cpus();
-
- nr_pages = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
-
- if (size < buffer_size) {
-
- /* easy case, just free pages */
- if (RB_WARN_ON(buffer, nr_pages >= buffer->pages))
- goto out_fail;
-
- rm_pages = buffer->pages - nr_pages;
-
- for_each_buffer_cpu(buffer, cpu) {
- cpu_buffer = buffer->buffers[cpu];
- rb_remove_pages(cpu_buffer, rm_pages);
- }
- goto out;
- }
-
- /*
- * This is a bit more difficult. We only want to add pages
- * when we can allocate enough for all CPUs. We do this
- * by allocating all the pages and storing them on a local
- * link list. If we succeed in our allocation, then we
- * add these pages to the cpu_buffers. Otherwise we just free
- * them all and return -ENOMEM;
- */
- if (RB_WARN_ON(buffer, nr_pages <= buffer->pages))
- goto out_fail;
-
- new_pages = nr_pages - buffer->pages;
-
- for_each_buffer_cpu(buffer, cpu) {
- for (i = 0; i < new_pages; i++) {
- bpage = kzalloc_node(ALIGN(sizeof(*bpage),
- cache_line_size()),
- GFP_KERNEL, cpu_to_node(cpu));
- if (!bpage)
- goto free_pages;
- list_add(&bpage->list, &pages);
- addr = __get_free_page(GFP_KERNEL);
- if (!addr)
- goto free_pages;
- bpage->page = (void *)addr;
- rb_init_page(bpage->page);
- }
- }
-
- for_each_buffer_cpu(buffer, cpu) {
- cpu_buffer = buffer->buffers[cpu];
- rb_insert_pages(cpu_buffer, &pages, new_pages);
- }
-
- if (RB_WARN_ON(buffer, !list_empty(&pages)))
- goto out_fail;
-
- out:
- buffer->pages = nr_pages;
- put_online_cpus();
- mutex_unlock(&buffer->mutex);
-
- atomic_dec(&buffer->record_disabled);
-
- return size;
-
- free_pages:
- list_for_each_entry_safe(bpage, tmp, &pages, list) {
- list_del_init(&bpage->list);
- free_buffer_page(bpage);
- }
- put_online_cpus();
- mutex_unlock(&buffer->mutex);
- atomic_dec(&buffer->record_disabled);
- return -ENOMEM;
-
- /*
- * Something went totally wrong, and we are too paranoid
- * to even clean up the mess.
- */
- out_fail:
- put_online_cpus();
- mutex_unlock(&buffer->mutex);
- atomic_dec(&buffer->record_disabled);
- return -1;
-}
-EXPORT_SYMBOL_GPL(ring_buffer_resize);
-
-static inline void *
-__rb_data_page_index(struct buffer_data_page *bpage, unsigned index)
-{
- return bpage->data + index;
-}
-
-static inline void *__rb_page_index(struct buffer_page *bpage, unsigned index)
-{
- return bpage->page->data + index;
-}
-
-static inline struct ring_buffer_event *
-rb_reader_event(struct ring_buffer_per_cpu *cpu_buffer)
-{
- return __rb_page_index(cpu_buffer->reader_page,
- cpu_buffer->reader_page->read);
-}
-
-static inline struct ring_buffer_event *
-rb_iter_head_event(struct ring_buffer_iter *iter)
-{
- return __rb_page_index(iter->head_page, iter->head);
-}
-
-static inline unsigned long rb_page_write(struct buffer_page *bpage)
-{
- return local_read(&bpage->write) & RB_WRITE_MASK;
-}
-
-static inline unsigned rb_page_commit(struct buffer_page *bpage)
-{
- return local_read(&bpage->page->commit);
-}
-
-static inline unsigned long rb_page_entries(struct buffer_page *bpage)
-{
- return local_read(&bpage->entries) & RB_WRITE_MASK;
-}
-
-/* Size is determined by what has been commited */
-static inline unsigned rb_page_size(struct buffer_page *bpage)
-{
- return rb_page_commit(bpage);
-}
-
-static inline unsigned
-rb_commit_index(struct ring_buffer_per_cpu *cpu_buffer)
-{
- return rb_page_commit(cpu_buffer->commit_page);
-}
-
-static inline unsigned
-rb_event_index(struct ring_buffer_event *event)
-{
- unsigned long addr = (unsigned long)event;
-
- return (addr & ~PAGE_MASK) - BUF_PAGE_HDR_SIZE;
-}
-
-static inline int
-rb_event_is_commit(struct ring_buffer_per_cpu *cpu_buffer,
- struct ring_buffer_event *event)
-{
- unsigned long addr = (unsigned long)event;
- unsigned long index;
-
- index = rb_event_index(event);
- addr &= PAGE_MASK;
-
- return cpu_buffer->commit_page->page == (void *)addr &&
- rb_commit_index(cpu_buffer) == index;
-}
-
-static void
-rb_set_commit_to_write(struct ring_buffer_per_cpu *cpu_buffer)
-{
- unsigned long max_count;
-
- /*
- * We only race with interrupts and NMIs on this CPU.
- * If we own the commit event, then we can commit
- * all others that interrupted us, since the interruptions
- * are in stack format (they finish before they come
- * back to us). This allows us to do a simple loop to
- * assign the commit to the tail.
- */
- again:
- max_count = cpu_buffer->buffer->pages * 100;
-
- while (cpu_buffer->commit_page != cpu_buffer->tail_page) {
- if (RB_WARN_ON(cpu_buffer, !(--max_count)))
- return;
- if (RB_WARN_ON(cpu_buffer,
- rb_is_reader_page(cpu_buffer->tail_page)))
- return;
- local_set(&cpu_buffer->commit_page->page->commit,
- rb_page_write(cpu_buffer->commit_page));
- rb_inc_page(cpu_buffer, &cpu_buffer->commit_page);
- cpu_buffer->write_stamp =
- cpu_buffer->commit_page->page->time_stamp;
- /* add barrier to keep gcc from optimizing too much */
- barrier();
- }
- while (rb_commit_index(cpu_buffer) !=
- rb_page_write(cpu_buffer->commit_page)) {
-
- local_set(&cpu_buffer->commit_page->page->commit,
- rb_page_write(cpu_buffer->commit_page));
- RB_WARN_ON(cpu_buffer,
- local_read(&cpu_buffer->commit_page->page->commit) &
- ~RB_WRITE_MASK);
- barrier();
- }
-
- /* again, keep gcc from optimizing */
- barrier();
-
- /*
- * If an interrupt came in just after the first while loop
- * and pushed the tail page forward, we will be left with
- * a dangling commit that will never go forward.
- */
- if (unlikely(cpu_buffer->commit_page != cpu_buffer->tail_page))
- goto again;
-}
-
-static void rb_reset_reader_page(struct ring_buffer_per_cpu *cpu_buffer)
-{
- cpu_buffer->read_stamp = cpu_buffer->reader_page->page->time_stamp;
- cpu_buffer->reader_page->read = 0;
-}
-
-static void rb_inc_iter(struct ring_buffer_iter *iter)
-{
- struct ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer;
-
- /*
- * The iterator could be on the reader page (it starts there).
- * But the head could have moved, since the reader was
- * found. Check for this case and assign the iterator
- * to the head page instead of next.
- */
- if (iter->head_page == cpu_buffer->reader_page)
- iter->head_page = rb_set_head_page(cpu_buffer);
- else
- rb_inc_page(cpu_buffer, &iter->head_page);
-
- iter->read_stamp = iter->head_page->page->time_stamp;
- iter->head = 0;
-}
-
-/**
- * ring_buffer_update_event - update event type and data
- * @event: the even to update
- * @type: the type of event
- * @length: the size of the event field in the ring buffer
- *
- * Update the type and data fields of the event. The length
- * is the actual size that is written to the ring buffer,
- * and with this, we can determine what to place into the
- * data field.
- */
-static void
-rb_update_event(struct ring_buffer_event *event,
- unsigned type, unsigned length)
-{
- event->type_len = type;
-
- switch (type) {
-
- case RINGBUF_TYPE_PADDING:
- case RINGBUF_TYPE_TIME_EXTEND:
- case RINGBUF_TYPE_TIME_STAMP:
- break;
-
- case 0:
- length -= RB_EVNT_HDR_SIZE;
- if (length > RB_MAX_SMALL_DATA || RB_FORCE_8BYTE_ALIGNMENT)
- event->array[0] = length;
- else
- event->type_len = DIV_ROUND_UP(length, RB_ALIGNMENT);
- break;
- default:
- BUG();
- }
-}
-
-/*
- * rb_handle_head_page - writer hit the head page
- *
- * Returns: +1 to retry page
- * 0 to continue
- * -1 on error
- */
-static int
-rb_handle_head_page(struct ring_buffer_per_cpu *cpu_buffer,
- struct buffer_page *tail_page,
- struct buffer_page *next_page)
-{
- struct buffer_page *new_head;
- int entries;
- int type;
- int ret;
-
- entries = rb_page_entries(next_page);
-
- /*
- * The hard part is here. We need to move the head
- * forward, and protect against both readers on
- * other CPUs and writers coming in via interrupts.
- */
- type = rb_head_page_set_update(cpu_buffer, next_page, tail_page,
- RB_PAGE_HEAD);
-
- /*
- * type can be one of four:
- * NORMAL - an interrupt already moved it for us
- * HEAD - we are the first to get here.
- * UPDATE - we are the interrupt interrupting
- * a current move.
- * MOVED - a reader on another CPU moved the next
- * pointer to its reader page. Give up
- * and try again.
- */
-
- switch (type) {
- case RB_PAGE_HEAD:
- /*
- * We changed the head to UPDATE, thus
- * it is our responsibility to update
- * the counters.
- */
- local_add(entries, &cpu_buffer->overrun);
-
- /*
- * The entries will be zeroed out when we move the
- * tail page.
- */
-
- /* still more to do */
- break;
-
- case RB_PAGE_UPDATE:
- /*
- * This is an interrupt that interrupt the
- * previous update. Still more to do.
- */
- break;
- case RB_PAGE_NORMAL:
- /*
- * An interrupt came in before the update
- * and processed this for us.
- * Nothing left to do.
- */
- return 1;
- case RB_PAGE_MOVED:
- /*
- * The reader is on another CPU and just did
- * a swap with our next_page.
- * Try again.
- */
- return 1;
- default:
- RB_WARN_ON(cpu_buffer, 1); /* WTF??? */
- return -1;
- }
-
- /*
- * Now that we are here, the old head pointer is
- * set to UPDATE. This will keep the reader from
- * swapping the head page with the reader page.
- * The reader (on another CPU) will spin till
- * we are finished.
- *
- * We just need to protect against interrupts
- * doing the job. We will set the next pointer
- * to HEAD. After that, we set the old pointer
- * to NORMAL, but only if it was HEAD before.
- * otherwise we are an interrupt, and only
- * want the outer most commit to reset it.
- */
- new_head = next_page;
- rb_inc_page(cpu_buffer, &new_head);
-
- ret = rb_head_page_set_head(cpu_buffer, new_head, next_page,
- RB_PAGE_NORMAL);
-
- /*
- * Valid returns are:
- * HEAD - an interrupt came in and already set it.
- * NORMAL - One of two things:
- * 1) We really set it.
- * 2) A bunch of interrupts came in and moved
- * the page forward again.
- */
- switch (ret) {
- case RB_PAGE_HEAD:
- case RB_PAGE_NORMAL:
- /* OK */
- break;
- default:
- RB_WARN_ON(cpu_buffer, 1);
- return -1;
- }
-
- /*
- * It is possible that an interrupt came in,
- * set the head up, then more interrupts came in
- * and moved it again. When we get back here,
- * the page would have been set to NORMAL but we
- * just set it back to HEAD.
- *
- * How do you detect this? Well, if that happened
- * the tail page would have moved.
- */
- if (ret == RB_PAGE_NORMAL) {
- /*
- * If the tail had moved passed next, then we need
- * to reset the pointer.
- */
- if (cpu_buffer->tail_page != tail_page &&
- cpu_buffer->tail_page != next_page)
- rb_head_page_set_normal(cpu_buffer, new_head,
- next_page,
- RB_PAGE_HEAD);
- }
-
- /*
- * If this was the outer most commit (the one that
- * changed the original pointer from HEAD to UPDATE),
- * then it is up to us to reset it to NORMAL.
- */
- if (type == RB_PAGE_HEAD) {
- ret = rb_head_page_set_normal(cpu_buffer, next_page,
- tail_page,
- RB_PAGE_UPDATE);
- if (RB_WARN_ON(cpu_buffer,
- ret != RB_PAGE_UPDATE))
- return -1;
- }
-
- return 0;
-}
-
-static unsigned rb_calculate_event_length(unsigned length)
-{
- struct ring_buffer_event event; /* Used only for sizeof array */
-
- /* zero length can cause confusions */
- if (!length)
- length = 1;
-
- if (length > RB_MAX_SMALL_DATA || RB_FORCE_8BYTE_ALIGNMENT)
- length += sizeof(event.array[0]);
-
- length += RB_EVNT_HDR_SIZE;
- length = ALIGN(length, RB_ARCH_ALIGNMENT);
-
- return length;
-}
-
-static inline void
-rb_reset_tail(struct ring_buffer_per_cpu *cpu_buffer,
- struct buffer_page *tail_page,
- unsigned long tail, unsigned long length)
-{
- struct ring_buffer_event *event;
-
- /*
- * Only the event that crossed the page boundary
- * must fill the old tail_page with padding.
- */
- if (tail >= BUF_PAGE_SIZE) {
- /*
- * If the page was filled, then we still need
- * to update the real_end. Reset it to zero
- * and the reader will ignore it.
- */
- if (tail == BUF_PAGE_SIZE)
- tail_page->real_end = 0;
-
- local_sub(length, &tail_page->write);
- return;
- }
-
- event = __rb_page_index(tail_page, tail);
- kmemcheck_annotate_bitfield(event, bitfield);
-
- /*
- * Save the original length to the meta data.
- * This will be used by the reader to add lost event
- * counter.
- */
- tail_page->real_end = tail;
-
- /*
- * If this event is bigger than the minimum size, then
- * we need to be careful that we don't subtract the
- * write counter enough to allow another writer to slip
- * in on this page.
- * We put in a discarded commit instead, to make sure
- * that this space is not used again.
- *
- * If we are less than the minimum size, we don't need to
- * worry about it.
- */
- if (tail > (BUF_PAGE_SIZE - RB_EVNT_MIN_SIZE)) {
- /* No room for any events */
-
- /* Mark the rest of the page with padding */
- rb_event_set_padding(event);
-
- /* Set the write back to the previous setting */
- local_sub(length, &tail_page->write);
- return;
- }
-
- /* Put in a discarded event */
- event->array[0] = (BUF_PAGE_SIZE - tail) - RB_EVNT_HDR_SIZE;
- event->type_len = RINGBUF_TYPE_PADDING;
- /* time delta must be non zero */
- event->time_delta = 1;
-
- /* Set write to end of buffer */
- length = (tail + length) - BUF_PAGE_SIZE;
- local_sub(length, &tail_page->write);
-}
-
-static struct ring_buffer_event *
-rb_move_tail(struct ring_buffer_per_cpu *cpu_buffer,
- unsigned long length, unsigned long tail,
- struct buffer_page *tail_page, u64 *ts)
-{
- struct buffer_page *commit_page = cpu_buffer->commit_page;
- struct ring_buffer *buffer = cpu_buffer->buffer;
- struct buffer_page *next_page;
- int ret;
-
- next_page = tail_page;
-
- rb_inc_page(cpu_buffer, &next_page);
-
- /*
- * If for some reason, we had an interrupt storm that made
- * it all the way around the buffer, bail, and warn
- * about it.
- */
- if (unlikely(next_page == commit_page)) {
- local_inc(&cpu_buffer->commit_overrun);
- goto out_reset;
- }
-
- /*
- * This is where the fun begins!
- *
- * We are fighting against races between a reader that
- * could be on another CPU trying to swap its reader
- * page with the buffer head.
- *
- * We are also fighting against interrupts coming in and
- * moving the head or tail on us as well.
- *
- * If the next page is the head page then we have filled
- * the buffer, unless the commit page is still on the
- * reader page.
- */
- if (rb_is_head_page(cpu_buffer, next_page, &tail_page->list)) {
-
- /*
- * If the commit is not on the reader page, then
- * move the header page.
- */
- if (!rb_is_reader_page(cpu_buffer->commit_page)) {
- /*
- * If we are not in overwrite mode,
- * this is easy, just stop here.
- */
- if (!(buffer->flags & RB_FL_OVERWRITE))
- goto out_reset;
-
- ret = rb_handle_head_page(cpu_buffer,
- tail_page,
- next_page);
- if (ret < 0)
- goto out_reset;
- if (ret)
- goto out_again;
- } else {
- /*
- * We need to be careful here too. The
- * commit page could still be on the reader
- * page. We could have a small buffer, and
- * have filled up the buffer with events
- * from interrupts and such, and wrapped.
- *
- * Note, if the tail page is also the on the
- * reader_page, we let it move out.
- */
- if (unlikely((cpu_buffer->commit_page !=
- cpu_buffer->tail_page) &&
- (cpu_buffer->commit_page ==
- cpu_buffer->reader_page))) {
- local_inc(&cpu_buffer->commit_overrun);
- goto out_reset;
- }
- }
- }
-
- ret = rb_tail_page_update(cpu_buffer, tail_page, next_page);
- if (ret) {
- /*
- * Nested commits always have zero deltas, so
- * just reread the time stamp
- */
- *ts = rb_time_stamp(buffer);
- next_page->page->time_stamp = *ts;
- }
-
- out_again:
-
- rb_reset_tail(cpu_buffer, tail_page, tail, length);
-
- /* fail and let the caller try again */
- return ERR_PTR(-EAGAIN);
-
- out_reset:
- /* reset write */
- rb_reset_tail(cpu_buffer, tail_page, tail, length);
-
- return NULL;
-}
-
-static struct ring_buffer_event *
-__rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer,
- unsigned type, unsigned long length, u64 *ts)
-{
- struct buffer_page *tail_page;
- struct ring_buffer_event *event;
- unsigned long tail, write;
-
- tail_page = cpu_buffer->tail_page;
- write = local_add_return(length, &tail_page->write);
-
- /* set write to only the index of the write */
- write &= RB_WRITE_MASK;
- tail = write - length;
-
- /* See if we shot pass the end of this buffer page */
- if (write > BUF_PAGE_SIZE)
- return rb_move_tail(cpu_buffer, length, tail,
- tail_page, ts);
-
- /* We reserved something on the buffer */
-
- event = __rb_page_index(tail_page, tail);
- kmemcheck_annotate_bitfield(event, bitfield);
- rb_update_event(event, type, length);
-
- /* The passed in type is zero for DATA */
- if (likely(!type))
- local_inc(&tail_page->entries);
-
- /*
- * If this is the first commit on the page, then update
- * its timestamp.
- */
- if (!tail)
- tail_page->page->time_stamp = *ts;
-
- return event;
-}
-
-static inline int
-rb_try_to_discard(struct ring_buffer_per_cpu *cpu_buffer,
- struct ring_buffer_event *event)
-{
- unsigned long new_index, old_index;
- struct buffer_page *bpage;
- unsigned long index;
- unsigned long addr;
-
- new_index = rb_event_index(event);
- old_index = new_index + rb_event_length(event);
- addr = (unsigned long)event;
- addr &= PAGE_MASK;
-
- bpage = cpu_buffer->tail_page;
-
- if (bpage->page == (void *)addr && rb_page_write(bpage) == old_index) {
- unsigned long write_mask =
- local_read(&bpage->write) & ~RB_WRITE_MASK;
- /*
- * This is on the tail page. It is possible that
- * a write could come in and move the tail page
- * and write to the next page. That is fine
- * because we just shorten what is on this page.
- */
- old_index += write_mask;
- new_index += write_mask;
- index = local_cmpxchg(&bpage->write, old_index, new_index);
- if (index == old_index)
- return 1;
- }
-
- /* could not discard */
- return 0;
-}
-
-static int
-rb_add_time_stamp(struct ring_buffer_per_cpu *cpu_buffer,
- u64 *ts, u64 *delta)
-{
- struct ring_buffer_event *event;
- int ret;
-
- WARN_ONCE(*delta > (1ULL << 59),
- KERN_WARNING "Delta way too big! %llu ts=%llu write stamp = %llu\n",
- (unsigned long long)*delta,
- (unsigned long long)*ts,
- (unsigned long long)cpu_buffer->write_stamp);
-
- /*
- * The delta is too big, we to add a
- * new timestamp.
- */
- event = __rb_reserve_next(cpu_buffer,
- RINGBUF_TYPE_TIME_EXTEND,
- RB_LEN_TIME_EXTEND,
- ts);
- if (!event)
- return -EBUSY;
-
- if (PTR_ERR(event) == -EAGAIN)
- return -EAGAIN;
-
- /* Only a commited time event can update the write stamp */
- if (rb_event_is_commit(cpu_buffer, event)) {
- /*
- * If this is the first on the page, then it was
- * updated with the page itself. Try to discard it
- * and if we can't just make it zero.
- */
- if (rb_event_index(event)) {
- event->time_delta = *delta & TS_MASK;
- event->array[0] = *delta >> TS_SHIFT;
- } else {
- /* try to discard, since we do not need this */
- if (!rb_try_to_discard(cpu_buffer, event)) {
- /* nope, just zero it */
- event->time_delta = 0;
- event->array[0] = 0;
- }
- }
- cpu_buffer->write_stamp = *ts;
- /* let the caller know this was the commit */
- ret = 1;
- } else {
- /* Try to discard the event */
- if (!rb_try_to_discard(cpu_buffer, event)) {
- /* Darn, this is just wasted space */
- event->time_delta = 0;
- event->array[0] = 0;
- }
- ret = 0;
- }
-
- *delta = 0;
-
- return ret;
-}
-
-static void rb_start_commit(struct ring_buffer_per_cpu *cpu_buffer)
-{
- local_inc(&cpu_buffer->committing);
- local_inc(&cpu_buffer->commits);
-}
-
-static void rb_end_commit(struct ring_buffer_per_cpu *cpu_buffer)
-{
- unsigned long commits;
-
- if (RB_WARN_ON(cpu_buffer,
- !local_read(&cpu_buffer->committing)))
- return;
-
- again:
- commits = local_read(&cpu_buffer->commits);
- /* synchronize with interrupts */
- barrier();
- if (local_read(&cpu_buffer->committing) == 1)
- rb_set_commit_to_write(cpu_buffer);
-
- local_dec(&cpu_buffer->committing);
-
- /* synchronize with interrupts */
- barrier();
-
- /*
- * Need to account for interrupts coming in between the
- * updating of the commit page and the clearing of the
- * committing counter.
- */
- if (unlikely(local_read(&cpu_buffer->commits) != commits) &&
- !local_read(&cpu_buffer->committing)) {
- local_inc(&cpu_buffer->committing);
- goto again;
- }
-}
-
-static struct ring_buffer_event *
-rb_reserve_next_event(struct ring_buffer *buffer,
- struct ring_buffer_per_cpu *cpu_buffer,
- unsigned long length)
-{
- struct ring_buffer_event *event;
- u64 ts, delta = 0;
- int commit = 0;
- int nr_loops = 0;
-
- rb_start_commit(cpu_buffer);
-
-#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
- /*
- * Due to the ability to swap a cpu buffer from a buffer
- * it is possible it was swapped before we committed.
- * (committing stops a swap). We check for it here and
- * if it happened, we have to fail the write.
- */
- barrier();
- if (unlikely(ACCESS_ONCE(cpu_buffer->buffer) != buffer)) {
- local_dec(&cpu_buffer->committing);
- local_dec(&cpu_buffer->commits);
- return NULL;
- }
-#endif
-
- length = rb_calculate_event_length(length);
- again:
- /*
- * We allow for interrupts to reenter here and do a trace.
- * If one does, it will cause this original code to loop
- * back here. Even with heavy interrupts happening, this
- * should only happen a few times in a row. If this happens
- * 1000 times in a row, there must be either an interrupt
- * storm or we have something buggy.
- * Bail!
- */
- if (RB_WARN_ON(cpu_buffer, ++nr_loops > 1000))
- goto out_fail;
-
- ts = rb_time_stamp(cpu_buffer->buffer);
-
- /*
- * Only the first commit can update the timestamp.
- * Yes there is a race here. If an interrupt comes in
- * just after the conditional and it traces too, then it
- * will also check the deltas. More than one timestamp may
- * also be made. But only the entry that did the actual
- * commit will be something other than zero.
- */
- if (likely(cpu_buffer->tail_page == cpu_buffer->commit_page &&
- rb_page_write(cpu_buffer->tail_page) ==
- rb_commit_index(cpu_buffer))) {
- u64 diff;
-
- diff = ts - cpu_buffer->write_stamp;
-
- /* make sure this diff is calculated here */
- barrier();
-
- /* Did the write stamp get updated already? */
- if (unlikely(ts < cpu_buffer->write_stamp))
- goto get_event;
-
- delta = diff;
- if (unlikely(test_time_stamp(delta))) {
-
- commit = rb_add_time_stamp(cpu_buffer, &ts, &delta);
- if (commit == -EBUSY)
- goto out_fail;
-
- if (commit == -EAGAIN)
- goto again;
-
- RB_WARN_ON(cpu_buffer, commit < 0);
- }
- }
-
- get_event:
- event = __rb_reserve_next(cpu_buffer, 0, length, &ts);
- if (unlikely(PTR_ERR(event) == -EAGAIN))
- goto again;
-
- if (!event)
- goto out_fail;
-
- if (!rb_event_is_commit(cpu_buffer, event))
- delta = 0;
-
- event->time_delta = delta;
-
- return event;
-
- out_fail:
- rb_end_commit(cpu_buffer);
- return NULL;
-}
-
-#ifdef CONFIG_TRACING
-
-#define TRACE_RECURSIVE_DEPTH 16
-
-static int trace_recursive_lock(void)
-{
- current->trace_recursion++;
-
- if (likely(current->trace_recursion < TRACE_RECURSIVE_DEPTH))
- return 0;
-
- /* Disable all tracing before we do anything else */
- tracing_off_permanent();
-
- printk_once(KERN_WARNING "Tracing recursion: depth[%ld]:"
- "HC[%lu]:SC[%lu]:NMI[%lu]\n",
- current->trace_recursion,
- hardirq_count() >> HARDIRQ_SHIFT,
- softirq_count() >> SOFTIRQ_SHIFT,
- in_nmi());
-
- WARN_ON_ONCE(1);
- return -1;
-}
-
-static void trace_recursive_unlock(void)
-{
- WARN_ON_ONCE(!current->trace_recursion);
-
- current->trace_recursion--;
-}
-
-#else
-
-#define trace_recursive_lock() (0)
-#define trace_recursive_unlock() do { } while (0)
-
-#endif
-
-/**
- * ring_buffer_lock_reserve - reserve a part of the buffer
- * @buffer: the ring buffer to reserve from
- * @length: the length of the data to reserve (excluding event header)
- *
- * Returns a reseverd event on the ring buffer to copy directly to.
- * The user of this interface will need to get the body to write into
- * and can use the ring_buffer_event_data() interface.
- *
- * The length is the length of the data needed, not the event length
- * which also includes the event header.
- *
- * Must be paired with ring_buffer_unlock_commit, unless NULL is returned.
- * If NULL is returned, then nothing has been allocated or locked.
- */
-struct ring_buffer_event *
-ring_buffer_lock_reserve(struct ring_buffer *buffer, unsigned long length)
-{
- struct ring_buffer_per_cpu *cpu_buffer;
- struct ring_buffer_event *event;
- int cpu;
-
- if (ring_buffer_flags != RB_BUFFERS_ON)
- return NULL;
-
- /* If we are tracing schedule, we don't want to recurse */
- preempt_disable_notrace();
-
- if (atomic_read(&buffer->record_disabled))
- goto out_nocheck;
-
- if (trace_recursive_lock())
- goto out_nocheck;
-
- cpu = raw_smp_processor_id();
-
- if (!cpumask_test_cpu(cpu, buffer->cpumask))
- goto out;
-
- cpu_buffer = buffer->buffers[cpu];
-
- if (atomic_read(&cpu_buffer->record_disabled))
- goto out;
-
- if (length > BUF_MAX_DATA_SIZE)
- goto out;
-
- event = rb_reserve_next_event(buffer, cpu_buffer, length);
- if (!event)
- goto out;
-
- return event;
-
- out:
- trace_recursive_unlock();
-
- out_nocheck:
- preempt_enable_notrace();
- return NULL;
-}
-EXPORT_SYMBOL_GPL(ring_buffer_lock_reserve);
-
-static void
-rb_update_write_stamp(struct ring_buffer_per_cpu *cpu_buffer,
- struct ring_buffer_event *event)
-{
- /*
- * The event first in the commit queue updates the
- * time stamp.
- */
- if (rb_event_is_commit(cpu_buffer, event))
- cpu_buffer->write_stamp += event->time_delta;
-}
-
-static void rb_commit(struct ring_buffer_per_cpu *cpu_buffer,
- struct ring_buffer_event *event)
-{
- local_inc(&cpu_buffer->entries);
- rb_update_write_stamp(cpu_buffer, event);
- rb_end_commit(cpu_buffer);
-}
-
-/**
- * ring_buffer_unlock_commit - commit a reserved
- * @buffer: The buffer to commit to
- * @event: The event pointer to commit.
- *
- * This commits the data to the ring buffer, and releases any locks held.
- *
- * Must be paired with ring_buffer_lock_reserve.
- */
-int ring_buffer_unlock_commit(struct ring_buffer *buffer,
- struct ring_buffer_event *event)
-{
- struct ring_buffer_per_cpu *cpu_buffer;
- int cpu = raw_smp_processor_id();
-
- cpu_buffer = buffer->buffers[cpu];
-
- rb_commit(cpu_buffer, event);
-
- trace_recursive_unlock();
-
- preempt_enable_notrace();
-
- return 0;
-}
-EXPORT_SYMBOL_GPL(ring_buffer_unlock_commit);
-
-static inline void rb_event_discard(struct ring_buffer_event *event)
-{
- /* array[0] holds the actual length for the discarded event */
- event->array[0] = rb_event_data_length(event) - RB_EVNT_HDR_SIZE;
- event->type_len = RINGBUF_TYPE_PADDING;
- /* time delta must be non zero */
- if (!event->time_delta)
- event->time_delta = 1;
-}
-
-/*
- * Decrement the entries to the page that an event is on.
- * The event does not even need to exist, only the pointer
- * to the page it is on. This may only be called before the commit
- * takes place.
- */
-static inline void
-rb_decrement_entry(struct ring_buffer_per_cpu *cpu_buffer,
- struct ring_buffer_event *event)
-{
- unsigned long addr = (unsigned long)event;
- struct buffer_page *bpage = cpu_buffer->commit_page;
- struct buffer_page *start;
-
- addr &= PAGE_MASK;
-
- /* Do the likely case first */
- if (likely(bpage->page == (void *)addr)) {
- local_dec(&bpage->entries);
- return;
- }
-
- /*
- * Because the commit page may be on the reader page we
- * start with the next page and check the end loop there.
- */
- rb_inc_page(cpu_buffer, &bpage);
- start = bpage;
- do {
- if (bpage->page == (void *)addr) {
- local_dec(&bpage->entries);
- return;
- }
- rb_inc_page(cpu_buffer, &bpage);
- } while (bpage != start);
-
- /* commit not part of this buffer?? */
- RB_WARN_ON(cpu_buffer, 1);
-}
-
-/**
- * ring_buffer_commit_discard - discard an event that has not been committed
- * @buffer: the ring buffer
- * @event: non committed event to discard
- *
- * Sometimes an event that is in the ring buffer needs to be ignored.
- * This function lets the user discard an event in the ring buffer
- * and then that event will not be read later.
- *
- * This function only works if it is called before the the item has been
- * committed. It will try to free the event from the ring buffer
- * if another event has not been added behind it.
- *
- * If another event has been added behind it, it will set the event
- * up as discarded, and perform the commit.
- *
- * If this function is called, do not call ring_buffer_unlock_commit on
- * the event.
- */
-void ring_buffer_discard_commit(struct ring_buffer *buffer,
- struct ring_buffer_event *event)
-{
- struct ring_buffer_per_cpu *cpu_buffer;
- int cpu;
-
- /* The event is discarded regardless */
- rb_event_discard(event);
-
- cpu = smp_processor_id();
- cpu_buffer = buffer->buffers[cpu];
-
- /*
- * This must only be called if the event has not been
- * committed yet. Thus we can assume that preemption
- * is still disabled.
- */
- RB_WARN_ON(buffer, !local_read(&cpu_buffer->committing));
-
- rb_decrement_entry(cpu_buffer, event);
- if (rb_try_to_discard(cpu_buffer, event))
- goto out;
-
- /*
- * The commit is still visible by the reader, so we
- * must still update the timestamp.
- */
- rb_update_write_stamp(cpu_buffer, event);
- out:
- rb_end_commit(cpu_buffer);
-
- trace_recursive_unlock();
-
- preempt_enable_notrace();
-
-}
-EXPORT_SYMBOL_GPL(ring_buffer_discard_commit);
-
-/**
- * ring_buffer_write - write data to the buffer without reserving
- * @buffer: The ring buffer to write to.
- * @length: The length of the data being written (excluding the event header)
- * @data: The data to write to the buffer.
- *
- * This is like ring_buffer_lock_reserve and ring_buffer_unlock_commit as
- * one function. If you already have the data to write to the buffer, it
- * may be easier to simply call this function.
- *
- * Note, like ring_buffer_lock_reserve, the length is the length of the data
- * and not the length of the event which would hold the header.
- */
-int ring_buffer_write(struct ring_buffer *buffer,
- unsigned long length,
- void *data)
-{
- struct ring_buffer_per_cpu *cpu_buffer;
- struct ring_buffer_event *event;
- void *body;
- int ret = -EBUSY;
- int cpu;
-
- if (ring_buffer_flags != RB_BUFFERS_ON)
- return -EBUSY;
-
- preempt_disable_notrace();
-
- if (atomic_read(&buffer->record_disabled))
- goto out;
-
- cpu = raw_smp_processor_id();
-
- if (!cpumask_test_cpu(cpu, buffer->cpumask))
- goto out;
-
- cpu_buffer = buffer->buffers[cpu];
-
- if (atomic_read(&cpu_buffer->record_disabled))
- goto out;
-
- if (length > BUF_MAX_DATA_SIZE)
- goto out;
-
- event = rb_reserve_next_event(buffer, cpu_buffer, length);
- if (!event)
- goto out;
-
- body = rb_event_data(event);
-
- memcpy(body, data, length);
-
- rb_commit(cpu_buffer, event);
-
- ret = 0;
- out:
- preempt_enable_notrace();
-
- return ret;
-}
-EXPORT_SYMBOL_GPL(ring_buffer_write);
-
-static int rb_per_cpu_empty(struct ring_buffer_per_cpu *cpu_buffer)
-{
- struct buffer_page *reader = cpu_buffer->reader_page;
- struct buffer_page *head = rb_set_head_page(cpu_buffer);
- struct buffer_page *commit = cpu_buffer->commit_page;
-
- /* In case of error, head will be NULL */
- if (unlikely(!head))
- return 1;
-
- return reader->read == rb_page_commit(reader) &&
- (commit == reader ||
- (commit == head &&
- head->read == rb_page_commit(commit)));
-}
-
-/**
- * ring_buffer_record_disable - stop all writes into the buffer
- * @buffer: The ring buffer to stop writes to.
- *
- * This prevents all writes to the buffer. Any attempt to write
- * to the buffer after this will fail and return NULL.
- *
- * The caller should call synchronize_sched() after this.
- */
-void ring_buffer_record_disable(struct ring_buffer *buffer)
-{
- atomic_inc(&buffer->record_disabled);
-}
-EXPORT_SYMBOL_GPL(ring_buffer_record_disable);
-
-/**
- * ring_buffer_record_enable - enable writes to the buffer
- * @buffer: The ring buffer to enable writes
- *
- * Note, multiple disables will need the same number of enables
- * to truly enable the writing (much like preempt_disable).
- */
-void ring_buffer_record_enable(struct ring_buffer *buffer)
-{
- atomic_dec(&buffer->record_disabled);
-}
-EXPORT_SYMBOL_GPL(ring_buffer_record_enable);
-
-/**
- * ring_buffer_record_disable_cpu - stop all writes into the cpu_buffer
- * @buffer: The ring buffer to stop writes to.
- * @cpu: The CPU buffer to stop
- *
- * This prevents all writes to the buffer. Any attempt to write
- * to the buffer after this will fail and return NULL.
- *
- * The caller should call synchronize_sched() after this.
- */
-void ring_buffer_record_disable_cpu(struct ring_buffer *buffer, int cpu)
-{
- struct ring_buffer_per_cpu *cpu_buffer;
-
- if (!cpumask_test_cpu(cpu, buffer->cpumask))
- return;
-
- cpu_buffer = buffer->buffers[cpu];
- atomic_inc(&cpu_buffer->record_disabled);
-}
-EXPORT_SYMBOL_GPL(ring_buffer_record_disable_cpu);
-
-/**
- * ring_buffer_record_enable_cpu - enable writes to the buffer
- * @buffer: The ring buffer to enable writes
- * @cpu: The CPU to enable.
- *
- * Note, multiple disables will need the same number of enables
- * to truly enable the writing (much like preempt_disable).
- */
-void ring_buffer_record_enable_cpu(struct ring_buffer *buffer, int cpu)
-{
- struct ring_buffer_per_cpu *cpu_buffer;
-
- if (!cpumask_test_cpu(cpu, buffer->cpumask))
- return;
-
- cpu_buffer = buffer->buffers[cpu];
- atomic_dec(&cpu_buffer->record_disabled);
-}
-EXPORT_SYMBOL_GPL(ring_buffer_record_enable_cpu);
-
-/**
- * ring_buffer_entries_cpu - get the number of entries in a cpu buffer
- * @buffer: The ring buffer
- * @cpu: The per CPU buffer to get the entries from.
- */
-unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu)
-{
- struct ring_buffer_per_cpu *cpu_buffer;
- unsigned long ret;
-
- if (!cpumask_test_cpu(cpu, buffer->cpumask))
- return 0;
-
- cpu_buffer = buffer->buffers[cpu];
- ret = (local_read(&cpu_buffer->entries) - local_read(&cpu_buffer->overrun))
- - cpu_buffer->read;
-
- return ret;
-}
-EXPORT_SYMBOL_GPL(ring_buffer_entries_cpu);
-
-/**
- * ring_buffer_overrun_cpu - get the number of overruns in a cpu_buffer
- * @buffer: The ring buffer
- * @cpu: The per CPU buffer to get the number of overruns from
- */
-unsigned long ring_buffer_overrun_cpu(struct ring_buffer *buffer, int cpu)
-{
- struct ring_buffer_per_cpu *cpu_buffer;
- unsigned long ret;
-
- if (!cpumask_test_cpu(cpu, buffer->cpumask))
- return 0;
-
- cpu_buffer = buffer->buffers[cpu];
- ret = local_read(&cpu_buffer->overrun);
-
- return ret;
-}
-EXPORT_SYMBOL_GPL(ring_buffer_overrun_cpu);
-
-/**
- * ring_buffer_commit_overrun_cpu - get the number of overruns caused by commits
- * @buffer: The ring buffer
- * @cpu: The per CPU buffer to get the number of overruns from
- */
-unsigned long
-ring_buffer_commit_overrun_cpu(struct ring_buffer *buffer, int cpu)
-{
- struct ring_buffer_per_cpu *cpu_buffer;
- unsigned long ret;
-
- if (!cpumask_test_cpu(cpu, buffer->cpumask))
- return 0;
-
- cpu_buffer = buffer->buffers[cpu];
- ret = local_read(&cpu_buffer->commit_overrun);
-
- return ret;
-}
-EXPORT_SYMBOL_GPL(ring_buffer_commit_overrun_cpu);
-
-/**
- * ring_buffer_entries - get the number of entries in a buffer
- * @buffer: The ring buffer
- *
- * Returns the total number of entries in the ring buffer
- * (all CPU entries)
- */
-unsigned long ring_buffer_entries(struct ring_buffer *buffer)
-{
- struct ring_buffer_per_cpu *cpu_buffer;
- unsigned long entries = 0;
- int cpu;
-
- /* if you care about this being correct, lock the buffer */
- for_each_buffer_cpu(buffer, cpu) {
- cpu_buffer = buffer->buffers[cpu];
- entries += (local_read(&cpu_buffer->entries) -
- local_read(&cpu_buffer->overrun)) - cpu_buffer->read;
- }
-
- return entries;
-}
-EXPORT_SYMBOL_GPL(ring_buffer_entries);
-
-/**
- * ring_buffer_overruns - get the number of overruns in buffer
- * @buffer: The ring buffer
- *
- * Returns the total number of overruns in the ring buffer
- * (all CPU entries)
- */
-unsigned long ring_buffer_overruns(struct ring_buffer *buffer)
-{
- struct ring_buffer_per_cpu *cpu_buffer;
- unsigned long overruns = 0;
- int cpu;
-
- /* if you care about this being correct, lock the buffer */
- for_each_buffer_cpu(buffer, cpu) {
- cpu_buffer = buffer->buffers[cpu];
- overruns += local_read(&cpu_buffer->overrun);
- }
-
- return overruns;
-}
-EXPORT_SYMBOL_GPL(ring_buffer_overruns);
-
-static void rb_iter_reset(struct ring_buffer_iter *iter)
-{
- struct ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer;
-
- /* Iterator usage is expected to have record disabled */
- if (list_empty(&cpu_buffer->reader_page->list)) {
- iter->head_page = rb_set_head_page(cpu_buffer);
- if (unlikely(!iter->head_page))
- return;
- iter->head = iter->head_page->read;
- } else {
- iter->head_page = cpu_buffer->reader_page;
- iter->head = cpu_buffer->reader_page->read;
- }
- if (iter->head)
- iter->read_stamp = cpu_buffer->read_stamp;
- else
- iter->read_stamp = iter->head_page->page->time_stamp;
- iter->cache_reader_page = cpu_buffer->reader_page;
- iter->cache_read = cpu_buffer->read;
-}
-
-/**
- * ring_buffer_iter_reset - reset an iterator
- * @iter: The iterator to reset
- *
- * Resets the iterator, so that it will start from the beginning
- * again.
- */
-void ring_buffer_iter_reset(struct ring_buffer_iter *iter)
-{
- struct ring_buffer_per_cpu *cpu_buffer;
- unsigned long flags;
-
- if (!iter)
- return;
-
- cpu_buffer = iter->cpu_buffer;
-
- spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
- rb_iter_reset(iter);
- spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
-}
-EXPORT_SYMBOL_GPL(ring_buffer_iter_reset);
-
-/**
- * ring_buffer_iter_empty - check if an iterator has no more to read
- * @iter: The iterator to check
- */
-int ring_buffer_iter_empty(struct ring_buffer_iter *iter)
-{
- struct ring_buffer_per_cpu *cpu_buffer;
-
- cpu_buffer = iter->cpu_buffer;
-
- return iter->head_page == cpu_buffer->commit_page &&
- iter->head == rb_commit_index(cpu_buffer);
-}
-EXPORT_SYMBOL_GPL(ring_buffer_iter_empty);
-
-static void
-rb_update_read_stamp(struct ring_buffer_per_cpu *cpu_buffer,
- struct ring_buffer_event *event)
-{
- u64 delta;
-
- switch (event->type_len) {
- case RINGBUF_TYPE_PADDING:
- return;
-
- case RINGBUF_TYPE_TIME_EXTEND:
- delta = event->array[0];
- delta <<= TS_SHIFT;
- delta += event->time_delta;
- cpu_buffer->read_stamp += delta;
- return;
-
- case RINGBUF_TYPE_TIME_STAMP:
- /* FIXME: not implemented */
- return;
-
- case RINGBUF_TYPE_DATA:
- cpu_buffer->read_stamp += event->time_delta;
- return;
-
- default:
- BUG();
- }
- return;
-}
-
-static void
-rb_update_iter_read_stamp(struct ring_buffer_iter *iter,
- struct ring_buffer_event *event)
-{
- u64 delta;
-
- switch (event->type_len) {
- case RINGBUF_TYPE_PADDING:
- return;
-
- case RINGBUF_TYPE_TIME_EXTEND:
- delta = event->array[0];
- delta <<= TS_SHIFT;
- delta += event->time_delta;
- iter->read_stamp += delta;
- return;
-
- case RINGBUF_TYPE_TIME_STAMP:
- /* FIXME: not implemented */
- return;
-
- case RINGBUF_TYPE_DATA:
- iter->read_stamp += event->time_delta;
- return;
-
- default:
- BUG();
- }
- return;
-}
-
-static struct buffer_page *
-rb_get_reader_page(struct ring_buffer_per_cpu *cpu_buffer)
-{
- struct buffer_page *reader = NULL;
- unsigned long overwrite;
- unsigned long flags;
- int nr_loops = 0;
- int ret;
-
- local_irq_save(flags);
- arch_spin_lock(&cpu_buffer->lock);
-
- again:
- /*
- * This should normally only loop twice. But because the
- * start of the reader inserts an empty page, it causes
- * a case where we will loop three times. There should be no
- * reason to loop four times (that I know of).
- */
- if (RB_WARN_ON(cpu_buffer, ++nr_loops > 3)) {
- reader = NULL;
- goto out;
- }
-
- reader = cpu_buffer->reader_page;
-
- /* If there's more to read, return this page */
- if (cpu_buffer->reader_page->read < rb_page_size(reader))
- goto out;
-
- /* Never should we have an index greater than the size */
- if (RB_WARN_ON(cpu_buffer,
- cpu_buffer->reader_page->read > rb_page_size(reader)))
- goto out;
-
- /* check if we caught up to the tail */
- reader = NULL;
- if (cpu_buffer->commit_page == cpu_buffer->reader_page)
- goto out;
-
- /*
- * Reset the reader page to size zero.
- */
- local_set(&cpu_buffer->reader_page->write, 0);
- local_set(&cpu_buffer->reader_page->entries, 0);
- local_set(&cpu_buffer->reader_page->page->commit, 0);
- cpu_buffer->reader_page->real_end = 0;
-
- spin:
- /*
- * Splice the empty reader page into the list around the head.
- */
- reader = rb_set_head_page(cpu_buffer);
- cpu_buffer->reader_page->list.next = rb_list_head(reader->list.next);
- cpu_buffer->reader_page->list.prev = reader->list.prev;
-
- /*
- * cpu_buffer->pages just needs to point to the buffer, it
- * has no specific buffer page to point to. Lets move it out
- * of our way so we don't accidently swap it.
- */
- cpu_buffer->pages = reader->list.prev;
-
- /* The reader page will be pointing to the new head */
- rb_set_list_to_head(cpu_buffer, &cpu_buffer->reader_page->list);
-
- /*
- * We want to make sure we read the overruns after we set up our
- * pointers to the next object. The writer side does a
- * cmpxchg to cross pages which acts as the mb on the writer
- * side. Note, the reader will constantly fail the swap
- * while the writer is updating the pointers, so this
- * guarantees that the overwrite recorded here is the one we
- * want to compare with the last_overrun.
- */
- smp_mb();
- overwrite = local_read(&(cpu_buffer->overrun));
-
- /*
- * Here's the tricky part.
- *
- * We need to move the pointer past the header page.
- * But we can only do that if a writer is not currently
- * moving it. The page before the header page has the
- * flag bit '1' set if it is pointing to the page we want.
- * but if the writer is in the process of moving it
- * than it will be '2' or already moved '0'.
- */
-
- ret = rb_head_page_replace(reader, cpu_buffer->reader_page);
-
- /*
- * If we did not convert it, then we must try again.
- */
- if (!ret)
- goto spin;
-
- /*
- * Yeah! We succeeded in replacing the page.
- *
- * Now make the new head point back to the reader page.
- */
- rb_list_head(reader->list.next)->prev = &cpu_buffer->reader_page->list;
- rb_inc_page(cpu_buffer, &cpu_buffer->head_page);
-
- /* Finally update the reader page to the new head */
- cpu_buffer->reader_page = reader;
- rb_reset_reader_page(cpu_buffer);
-
- if (overwrite != cpu_buffer->last_overrun) {
- cpu_buffer->lost_events = overwrite - cpu_buffer->last_overrun;
- cpu_buffer->last_overrun = overwrite;
- }
-
- goto again;
-
- out:
- arch_spin_unlock(&cpu_buffer->lock);
- local_irq_restore(flags);
-
- return reader;
-}
-
-static void rb_advance_reader(struct ring_buffer_per_cpu *cpu_buffer)
-{
- struct ring_buffer_event *event;
- struct buffer_page *reader;
- unsigned length;
-
- reader = rb_get_reader_page(cpu_buffer);
-
- /* This function should not be called when buffer is empty */
- if (RB_WARN_ON(cpu_buffer, !reader))
- return;
-
- event = rb_reader_event(cpu_buffer);
-
- if (event->type_len <= RINGBUF_TYPE_DATA_TYPE_LEN_MAX)
- cpu_buffer->read++;
-
- rb_update_read_stamp(cpu_buffer, event);
-
- length = rb_event_length(event);
- cpu_buffer->reader_page->read += length;
-}
-
-static void rb_advance_iter(struct ring_buffer_iter *iter)
-{
- struct ring_buffer *buffer;
- struct ring_buffer_per_cpu *cpu_buffer;
- struct ring_buffer_event *event;
- unsigned length;
-
- cpu_buffer = iter->cpu_buffer;
- buffer = cpu_buffer->buffer;
-
- /*
- * Check if we are at the end of the buffer.
- */
- if (iter->head >= rb_page_size(iter->head_page)) {
- /* discarded commits can make the page empty */
- if (iter->head_page == cpu_buffer->commit_page)
- return;
- rb_inc_iter(iter);
- return;
- }
-
- event = rb_iter_head_event(iter);
-
- length = rb_event_length(event);
-
- /*
- * This should not be called to advance the header if we are
- * at the tail of the buffer.
- */
- if (RB_WARN_ON(cpu_buffer,
- (iter->head_page == cpu_buffer->commit_page) &&
- (iter->head + length > rb_commit_index(cpu_buffer))))
- return;
-
- rb_update_iter_read_stamp(iter, event);
-
- iter->head += length;
-
- /* check for end of page padding */
- if ((iter->head >= rb_page_size(iter->head_page)) &&
- (iter->head_page != cpu_buffer->commit_page))
- rb_advance_iter(iter);
-}
-
-static int rb_lost_events(struct ring_buffer_per_cpu *cpu_buffer)
-{
- return cpu_buffer->lost_events;
-}
-
-static struct ring_buffer_event *
-rb_buffer_peek(struct ring_buffer_per_cpu *cpu_buffer, u64 *ts,
- unsigned long *lost_events)
-{
- struct ring_buffer_event *event;
- struct buffer_page *reader;
- int nr_loops = 0;
-
- again:
- /*
- * We repeat when a timestamp is encountered. It is possible
- * to get multiple timestamps from an interrupt entering just
- * as one timestamp is about to be written, or from discarded
- * commits. The most that we can have is the number on a single page.
- */
- if (RB_WARN_ON(cpu_buffer, ++nr_loops > RB_TIMESTAMPS_PER_PAGE))
- return NULL;
-
- reader = rb_get_reader_page(cpu_buffer);
- if (!reader)
- return NULL;
-
- event = rb_reader_event(cpu_buffer);
-
- switch (event->type_len) {
- case RINGBUF_TYPE_PADDING:
- if (rb_null_event(event))
- RB_WARN_ON(cpu_buffer, 1);
- /*
- * Because the writer could be discarding every
- * event it creates (which would probably be bad)
- * if we were to go back to "again" then we may never
- * catch up, and will trigger the warn on, or lock
- * the box. Return the padding, and we will release
- * the current locks, and try again.
- */
- return event;
-
- case RINGBUF_TYPE_TIME_EXTEND:
- /* Internal data, OK to advance */
- rb_advance_reader(cpu_buffer);
- goto again;
-
- case RINGBUF_TYPE_TIME_STAMP:
- /* FIXME: not implemented */
- rb_advance_reader(cpu_buffer);
- goto again;
-
- case RINGBUF_TYPE_DATA:
- if (ts) {
- *ts = cpu_buffer->read_stamp + event->time_delta;
- ring_buffer_normalize_time_stamp(cpu_buffer->buffer,
- cpu_buffer->cpu, ts);
- }
- if (lost_events)
- *lost_events = rb_lost_events(cpu_buffer);
- return event;
-
- default:
- BUG();
- }
-
- return NULL;
-}
-EXPORT_SYMBOL_GPL(ring_buffer_peek);
-
-static struct ring_buffer_event *
-rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts)
-{
- struct ring_buffer *buffer;
- struct ring_buffer_per_cpu *cpu_buffer;
- struct ring_buffer_event *event;
- int nr_loops = 0;
-
- cpu_buffer = iter->cpu_buffer;
- buffer = cpu_buffer->buffer;
-
- /*
- * Check if someone performed a consuming read to
- * the buffer. A consuming read invalidates the iterator
- * and we need to reset the iterator in this case.
- */
- if (unlikely(iter->cache_read != cpu_buffer->read ||
- iter->cache_reader_page != cpu_buffer->reader_page))
- rb_iter_reset(iter);
-
- again:
- if (ring_buffer_iter_empty(iter))
- return NULL;
-
- /*
- * We repeat when a timestamp is encountered.
- * We can get multiple timestamps by nested interrupts or also
- * if filtering is on (discarding commits). Since discarding
- * commits can be frequent we can get a lot of timestamps.
- * But we limit them by not adding timestamps if they begin
- * at the start of a page.
- */
- if (RB_WARN_ON(cpu_buffer, ++nr_loops > RB_TIMESTAMPS_PER_PAGE))
- return NULL;
-
- if (rb_per_cpu_empty(cpu_buffer))
- return NULL;
-
- if (iter->head >= local_read(&iter->head_page->page->commit)) {
- rb_inc_iter(iter);
- goto again;
- }
-
- event = rb_iter_head_event(iter);
-
- switch (event->type_len) {
- case RINGBUF_TYPE_PADDING:
- if (rb_null_event(event)) {
- rb_inc_iter(iter);
- goto again;
- }
- rb_advance_iter(iter);
- return event;
-
- case RINGBUF_TYPE_TIME_EXTEND:
- /* Internal data, OK to advance */
- rb_advance_iter(iter);
- goto again;
-
- case RINGBUF_TYPE_TIME_STAMP:
- /* FIXME: not implemented */
- rb_advance_iter(iter);
- goto again;
-
- case RINGBUF_TYPE_DATA:
- if (ts) {
- *ts = iter->read_stamp + event->time_delta;
- ring_buffer_normalize_time_stamp(buffer,
- cpu_buffer->cpu, ts);
- }
- return event;
-
- default:
- BUG();
- }
-
- return NULL;
-}
-EXPORT_SYMBOL_GPL(ring_buffer_iter_peek);
-
-static inline int rb_ok_to_lock(void)
-{
- /*
- * If an NMI die dumps out the content of the ring buffer
- * do not grab locks. We also permanently disable the ring
- * buffer too. A one time deal is all you get from reading
- * the ring buffer from an NMI.
- */
- if (likely(!in_nmi()))
- return 1;
-
- tracing_off_permanent();
- return 0;
-}
-
-/**
- * ring_buffer_peek - peek at the next event to be read
- * @buffer: The ring buffer to read
- * @cpu: The cpu to peak at
- * @ts: The timestamp counter of this event.
- * @lost_events: a variable to store if events were lost (may be NULL)
- *
- * This will return the event that will be read next, but does
- * not consume the data.
- */
-struct ring_buffer_event *
-ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts,
- unsigned long *lost_events)
-{
- struct ring_buffer_per_cpu *cpu_buffer = buffer->buffers[cpu];
- struct ring_buffer_event *event;
- unsigned long flags;
- int dolock;
-
- if (!cpumask_test_cpu(cpu, buffer->cpumask))
- return NULL;
-
- dolock = rb_ok_to_lock();
- again:
- local_irq_save(flags);
- if (dolock)
- spin_lock(&cpu_buffer->reader_lock);
- event = rb_buffer_peek(cpu_buffer, ts, lost_events);
- if (event && event->type_len == RINGBUF_TYPE_PADDING)
- rb_advance_reader(cpu_buffer);
- if (dolock)
- spin_unlock(&cpu_buffer->reader_lock);
- local_irq_restore(flags);
-
- if (event && event->type_len == RINGBUF_TYPE_PADDING)
- goto again;
-
- return event;
-}
-
-/**
- * ring_buffer_iter_peek - peek at the next event to be read
- * @iter: The ring buffer iterator
- * @ts: The timestamp counter of this event.
- *
- * This will return the event that will be read next, but does
- * not increment the iterator.
- */
-struct ring_buffer_event *
-ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts)
-{
- struct ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer;
- struct ring_buffer_event *event;
- unsigned long flags;
-
- again:
- spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
- event = rb_iter_peek(iter, ts);
- spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
-
- if (event && event->type_len == RINGBUF_TYPE_PADDING)
- goto again;
-
- return event;
-}
-
-/**
- * ring_buffer_consume - return an event and consume it
- * @buffer: The ring buffer to get the next event from
- * @cpu: the cpu to read the buffer from
- * @ts: a variable to store the timestamp (may be NULL)
- * @lost_events: a variable to store if events were lost (may be NULL)
- *
- * Returns the next event in the ring buffer, and that event is consumed.
- * Meaning, that sequential reads will keep returning a different event,
- * and eventually empty the ring buffer if the producer is slower.
- */
-struct ring_buffer_event *
-ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts,
- unsigned long *lost_events)
-{
- struct ring_buffer_per_cpu *cpu_buffer;
- struct ring_buffer_event *event = NULL;
- unsigned long flags;
- int dolock;
-
- dolock = rb_ok_to_lock();
-
- again:
- /* might be called in atomic */
- preempt_disable();
-
- if (!cpumask_test_cpu(cpu, buffer->cpumask))
- goto out;
-
- cpu_buffer = buffer->buffers[cpu];
- local_irq_save(flags);
- if (dolock)
- spin_lock(&cpu_buffer->reader_lock);
-
- event = rb_buffer_peek(cpu_buffer, ts, lost_events);
- if (event) {
- cpu_buffer->lost_events = 0;
- rb_advance_reader(cpu_buffer);
- }
-
- if (dolock)
- spin_unlock(&cpu_buffer->reader_lock);
- local_irq_restore(flags);
-
- out:
- preempt_enable();
-
- if (event && event->type_len == RINGBUF_TYPE_PADDING)
- goto again;
-
- return event;
-}
-EXPORT_SYMBOL_GPL(ring_buffer_consume);
-
-/**
- * ring_buffer_read_prepare - Prepare for a non consuming read of the buffer
- * @buffer: The ring buffer to read from
- * @cpu: The cpu buffer to iterate over
- *
- * This performs the initial preparations necessary to iterate
- * through the buffer. Memory is allocated, buffer recording
- * is disabled, and the iterator pointer is returned to the caller.
- *
- * Disabling buffer recordng prevents the reading from being
- * corrupted. This is not a consuming read, so a producer is not
- * expected.
- *
- * After a sequence of ring_buffer_read_prepare calls, the user is
- * expected to make at least one call to ring_buffer_prepare_sync.
- * Afterwards, ring_buffer_read_start is invoked to get things going
- * for real.
- *
- * This overall must be paired with ring_buffer_finish.
- */
-struct ring_buffer_iter *
-ring_buffer_read_prepare(struct ring_buffer *buffer, int cpu)
-{
- struct ring_buffer_per_cpu *cpu_buffer;
- struct ring_buffer_iter *iter;
-
- if (!cpumask_test_cpu(cpu, buffer->cpumask))
- return NULL;
-
- iter = kmalloc(sizeof(*iter), GFP_KERNEL);
- if (!iter)
- return NULL;
-
- cpu_buffer = buffer->buffers[cpu];
-
- iter->cpu_buffer = cpu_buffer;
-
- atomic_inc(&cpu_buffer->record_disabled);
-
- return iter;
-}
-EXPORT_SYMBOL_GPL(ring_buffer_read_prepare);
-
-/**
- * ring_buffer_read_prepare_sync - Synchronize a set of prepare calls
- *
- * All previously invoked ring_buffer_read_prepare calls to prepare
- * iterators will be synchronized. Afterwards, read_buffer_read_start
- * calls on those iterators are allowed.
- */
-void
-ring_buffer_read_prepare_sync(void)
-{
- synchronize_sched();
-}
-EXPORT_SYMBOL_GPL(ring_buffer_read_prepare_sync);
-
-/**
- * ring_buffer_read_start - start a non consuming read of the buffer
- * @iter: The iterator returned by ring_buffer_read_prepare
- *
- * This finalizes the startup of an iteration through the buffer.
- * The iterator comes from a call to ring_buffer_read_prepare and
- * an intervening ring_buffer_read_prepare_sync must have been
- * performed.
- *
- * Must be paired with ring_buffer_finish.
- */
-void
-ring_buffer_read_start(struct ring_buffer_iter *iter)
-{
- struct ring_buffer_per_cpu *cpu_buffer;
- unsigned long flags;
-
- if (!iter)
- return;
-
- cpu_buffer = iter->cpu_buffer;
-
- spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
- arch_spin_lock(&cpu_buffer->lock);
- rb_iter_reset(iter);
- arch_spin_unlock(&cpu_buffer->lock);
- spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
-}
-EXPORT_SYMBOL_GPL(ring_buffer_read_start);
-
-/**
- * ring_buffer_finish - finish reading the iterator of the buffer
- * @iter: The iterator retrieved by ring_buffer_start
- *
- * This re-enables the recording to the buffer, and frees the
- * iterator.
- */
-void
-ring_buffer_read_finish(struct ring_buffer_iter *iter)
-{
- struct ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer;
-
- atomic_dec(&cpu_buffer->record_disabled);
- kfree(iter);
-}
-EXPORT_SYMBOL_GPL(ring_buffer_read_finish);
-
-/**
- * ring_buffer_read - read the next item in the ring buffer by the iterator
- * @iter: The ring buffer iterator
- * @ts: The time stamp of the event read.
- *
- * This reads the next event in the ring buffer and increments the iterator.
- */
-struct ring_buffer_event *
-ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts)
-{
- struct ring_buffer_event *event;
- struct ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer;
- unsigned long flags;
-
- spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
- again:
- event = rb_iter_peek(iter, ts);
- if (!event)
- goto out;
-
- if (event->type_len == RINGBUF_TYPE_PADDING)
- goto again;
-
- rb_advance_iter(iter);
- out:
- spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
-
- return event;
-}
-EXPORT_SYMBOL_GPL(ring_buffer_read);
-
-/**
- * ring_buffer_size - return the size of the ring buffer (in bytes)
- * @buffer: The ring buffer.
- */
-unsigned long ring_buffer_size(struct ring_buffer *buffer)
-{
- return BUF_PAGE_SIZE * buffer->pages;
-}
-EXPORT_SYMBOL_GPL(ring_buffer_size);
-
-static void
-rb_reset_cpu(struct ring_buffer_per_cpu *cpu_buffer)
-{
- rb_head_page_deactivate(cpu_buffer);
-
- cpu_buffer->head_page
- = list_entry(cpu_buffer->pages, struct buffer_page, list);
- local_set(&cpu_buffer->head_page->write, 0);
- local_set(&cpu_buffer->head_page->entries, 0);
- local_set(&cpu_buffer->head_page->page->commit, 0);
-
- cpu_buffer->head_page->read = 0;
-
- cpu_buffer->tail_page = cpu_buffer->head_page;
- cpu_buffer->commit_page = cpu_buffer->head_page;
-
- INIT_LIST_HEAD(&cpu_buffer->reader_page->list);
- local_set(&cpu_buffer->reader_page->write, 0);
- local_set(&cpu_buffer->reader_page->entries, 0);
- local_set(&cpu_buffer->reader_page->page->commit, 0);
- cpu_buffer->reader_page->read = 0;
-
- local_set(&cpu_buffer->commit_overrun, 0);
- local_set(&cpu_buffer->overrun, 0);
- local_set(&cpu_buffer->entries, 0);
- local_set(&cpu_buffer->committing, 0);
- local_set(&cpu_buffer->commits, 0);
- cpu_buffer->read = 0;
-
- cpu_buffer->write_stamp = 0;
- cpu_buffer->read_stamp = 0;
-
- cpu_buffer->lost_events = 0;
- cpu_buffer->last_overrun = 0;
-
- rb_head_page_activate(cpu_buffer);
-}
-
-/**
- * ring_buffer_reset_cpu - reset a ring buffer per CPU buffer
- * @buffer: The ring buffer to reset a per cpu buffer of
- * @cpu: The CPU buffer to be reset
- */
-void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu)
-{
- struct ring_buffer_per_cpu *cpu_buffer = buffer->buffers[cpu];
- unsigned long flags;
-
- if (!cpumask_test_cpu(cpu, buffer->cpumask))
- return;
-
- atomic_inc(&cpu_buffer->record_disabled);
-
- spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
-
- if (RB_WARN_ON(cpu_buffer, local_read(&cpu_buffer->committing)))
- goto out;
-
- arch_spin_lock(&cpu_buffer->lock);
-
- rb_reset_cpu(cpu_buffer);
-
- arch_spin_unlock(&cpu_buffer->lock);
-
- out:
- spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
-
- atomic_dec(&cpu_buffer->record_disabled);
-}
-EXPORT_SYMBOL_GPL(ring_buffer_reset_cpu);
-
-/**
- * ring_buffer_reset - reset a ring buffer
- * @buffer: The ring buffer to reset all cpu buffers
- */
-void ring_buffer_reset(struct ring_buffer *buffer)
-{
- int cpu;
-
- for_each_buffer_cpu(buffer, cpu)
- ring_buffer_reset_cpu(buffer, cpu);
-}
-EXPORT_SYMBOL_GPL(ring_buffer_reset);
-
-/**
- * rind_buffer_empty - is the ring buffer empty?
- * @buffer: The ring buffer to test
- */
-int ring_buffer_empty(struct ring_buffer *buffer)
-{
- struct ring_buffer_per_cpu *cpu_buffer;
- unsigned long flags;
- int dolock;
- int cpu;
- int ret;
-
- dolock = rb_ok_to_lock();
-
- /* yes this is racy, but if you don't like the race, lock the buffer */
- for_each_buffer_cpu(buffer, cpu) {
- cpu_buffer = buffer->buffers[cpu];
- local_irq_save(flags);
- if (dolock)
- spin_lock(&cpu_buffer->reader_lock);
- ret = rb_per_cpu_empty(cpu_buffer);
- if (dolock)
- spin_unlock(&cpu_buffer->reader_lock);
- local_irq_restore(flags);
-
- if (!ret)
- return 0;
- }
-
- return 1;
-}
-EXPORT_SYMBOL_GPL(ring_buffer_empty);
-
-/**
- * ring_buffer_empty_cpu - is a cpu buffer of a ring buffer empty?
- * @buffer: The ring buffer
- * @cpu: The CPU buffer to test
- */
-int ring_buffer_empty_cpu(struct ring_buffer *buffer, int cpu)
-{
- struct ring_buffer_per_cpu *cpu_buffer;
- unsigned long flags;
- int dolock;
- int ret;
-
- if (!cpumask_test_cpu(cpu, buffer->cpumask))
- return 1;
-
- dolock = rb_ok_to_lock();
-
- cpu_buffer = buffer->buffers[cpu];
- local_irq_save(flags);
- if (dolock)
- spin_lock(&cpu_buffer->reader_lock);
- ret = rb_per_cpu_empty(cpu_buffer);
- if (dolock)
- spin_unlock(&cpu_buffer->reader_lock);
- local_irq_restore(flags);
-
- return ret;
-}
-EXPORT_SYMBOL_GPL(ring_buffer_empty_cpu);
-
-#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
-/**
- * ring_buffer_swap_cpu - swap a CPU buffer between two ring buffers
- * @buffer_a: One buffer to swap with
- * @buffer_b: The other buffer to swap with
- *
- * This function is useful for tracers that want to take a "snapshot"
- * of a CPU buffer and has another back up buffer lying around.
- * it is expected that the tracer handles the cpu buffer not being
- * used at the moment.
- */
-int ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
- struct ring_buffer *buffer_b, int cpu)
-{
- struct ring_buffer_per_cpu *cpu_buffer_a;
- struct ring_buffer_per_cpu *cpu_buffer_b;
- int ret = -EINVAL;
-
- if (!cpumask_test_cpu(cpu, buffer_a->cpumask) ||
- !cpumask_test_cpu(cpu, buffer_b->cpumask))
- goto out;
-
- /* At least make sure the two buffers are somewhat the same */
- if (buffer_a->pages != buffer_b->pages)
- goto out;
-
- ret = -EAGAIN;
-
- if (ring_buffer_flags != RB_BUFFERS_ON)
- goto out;
-
- if (atomic_read(&buffer_a->record_disabled))
- goto out;
-
- if (atomic_read(&buffer_b->record_disabled))
- goto out;
-
- cpu_buffer_a = buffer_a->buffers[cpu];
- cpu_buffer_b = buffer_b->buffers[cpu];
-
- if (atomic_read(&cpu_buffer_a->record_disabled))
- goto out;
-
- if (atomic_read(&cpu_buffer_b->record_disabled))
- goto out;
-
- /*
- * We can't do a synchronize_sched here because this
- * function can be called in atomic context.
- * Normally this will be called from the same CPU as cpu.
- * If not it's up to the caller to protect this.
- */
- atomic_inc(&cpu_buffer_a->record_disabled);
- atomic_inc(&cpu_buffer_b->record_disabled);
-
- ret = -EBUSY;
- if (local_read(&cpu_buffer_a->committing))
- goto out_dec;
- if (local_read(&cpu_buffer_b->committing))
- goto out_dec;
-
- buffer_a->buffers[cpu] = cpu_buffer_b;
- buffer_b->buffers[cpu] = cpu_buffer_a;
-
- cpu_buffer_b->buffer = buffer_a;
- cpu_buffer_a->buffer = buffer_b;
-
- ret = 0;
-
-out_dec:
- atomic_dec(&cpu_buffer_a->record_disabled);
- atomic_dec(&cpu_buffer_b->record_disabled);
-out:
- return ret;
-}
-EXPORT_SYMBOL_GPL(ring_buffer_swap_cpu);
-#endif /* CONFIG_RING_BUFFER_ALLOW_SWAP */
-
-/**
- * ring_buffer_alloc_read_page - allocate a page to read from buffer
- * @buffer: the buffer to allocate for.
- *
- * This function is used in conjunction with ring_buffer_read_page.
- * When reading a full page from the ring buffer, these functions
- * can be used to speed up the process. The calling function should
- * allocate a few pages first with this function. Then when it
- * needs to get pages from the ring buffer, it passes the result
- * of this function into ring_buffer_read_page, which will swap
- * the page that was allocated, with the read page of the buffer.
- *
- * Returns:
- * The page allocated, or NULL on error.
- */
-void *ring_buffer_alloc_read_page(struct ring_buffer *buffer)
-{
- struct buffer_data_page *bpage;
- unsigned long addr;
-
- addr = __get_free_page(GFP_KERNEL);
- if (!addr)
- return NULL;
-
- bpage = (void *)addr;
-
- rb_init_page(bpage);
-
- return bpage;
-}
-EXPORT_SYMBOL_GPL(ring_buffer_alloc_read_page);
-
-/**
- * ring_buffer_free_read_page - free an allocated read page
- * @buffer: the buffer the page was allocate for
- * @data: the page to free
- *
- * Free a page allocated from ring_buffer_alloc_read_page.
- */
-void ring_buffer_free_read_page(struct ring_buffer *buffer, void *data)
-{
- free_page((unsigned long)data);
-}
-EXPORT_SYMBOL_GPL(ring_buffer_free_read_page);
-
-/**
- * ring_buffer_read_page - extract a page from the ring buffer
- * @buffer: buffer to extract from
- * @data_page: the page to use allocated from ring_buffer_alloc_read_page
- * @len: amount to extract
- * @cpu: the cpu of the buffer to extract
- * @full: should the extraction only happen when the page is full.
- *
- * This function will pull out a page from the ring buffer and consume it.
- * @data_page must be the address of the variable that was returned
- * from ring_buffer_alloc_read_page. This is because the page might be used
- * to swap with a page in the ring buffer.
- *
- * for example:
- * rpage = ring_buffer_alloc_read_page(buffer);
- * if (!rpage)
- * return error;
- * ret = ring_buffer_read_page(buffer, &rpage, len, cpu, 0);
- * if (ret >= 0)
- * process_page(rpage, ret);
- *
- * When @full is set, the function will not return true unless
- * the writer is off the reader page.
- *
- * Note: it is up to the calling functions to handle sleeps and wakeups.
- * The ring buffer can be used anywhere in the kernel and can not
- * blindly call wake_up. The layer that uses the ring buffer must be
- * responsible for that.
- *
- * Returns:
- * >=0 if data has been transferred, returns the offset of consumed data.
- * <0 if no data has been transferred.
- */
-int ring_buffer_read_page(struct ring_buffer *buffer,
- void **data_page, size_t len, int cpu, int full)
-{
- struct ring_buffer_per_cpu *cpu_buffer = buffer->buffers[cpu];
- struct ring_buffer_event *event;
- struct buffer_data_page *bpage;
- struct buffer_page *reader;
- unsigned long missed_events;
- unsigned long flags;
- unsigned int commit;
- unsigned int read;
- u64 save_timestamp;
- int ret = -1;
-
- if (!cpumask_test_cpu(cpu, buffer->cpumask))
- goto out;
-
- /*
- * If len is not big enough to hold the page header, then
- * we can not copy anything.
- */
- if (len <= BUF_PAGE_HDR_SIZE)
- goto out;
-
- len -= BUF_PAGE_HDR_SIZE;
-
- if (!data_page)
- goto out;
-
- bpage = *data_page;
- if (!bpage)
- goto out;
-
- spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
-
- reader = rb_get_reader_page(cpu_buffer);
- if (!reader)
- goto out_unlock;
-
- event = rb_reader_event(cpu_buffer);
-
- read = reader->read;
- commit = rb_page_commit(reader);
-
- /* Check if any events were dropped */
- missed_events = cpu_buffer->lost_events;
-
- /*
- * If this page has been partially read or
- * if len is not big enough to read the rest of the page or
- * a writer is still on the page, then
- * we must copy the data from the page to the buffer.
- * Otherwise, we can simply swap the page with the one passed in.
- */
- if (read || (len < (commit - read)) ||
- cpu_buffer->reader_page == cpu_buffer->commit_page) {
- struct buffer_data_page *rpage = cpu_buffer->reader_page->page;
- unsigned int rpos = read;
- unsigned int pos = 0;
- unsigned int size;
-
- if (full)
- goto out_unlock;
-
- if (len > (commit - read))
- len = (commit - read);
-
- size = rb_event_length(event);
-
- if (len < size)
- goto out_unlock;
-
- /* save the current timestamp, since the user will need it */
- save_timestamp = cpu_buffer->read_stamp;
-
- /* Need to copy one event at a time */
- do {
- memcpy(bpage->data + pos, rpage->data + rpos, size);
-
- len -= size;
-
- rb_advance_reader(cpu_buffer);
- rpos = reader->read;
- pos += size;
-
- event = rb_reader_event(cpu_buffer);
- size = rb_event_length(event);
- } while (len > size);
-
- /* update bpage */
- local_set(&bpage->commit, pos);
- bpage->time_stamp = save_timestamp;
-
- /* we copied everything to the beginning */
- read = 0;
- } else {
- /* update the entry counter */
- cpu_buffer->read += rb_page_entries(reader);
-
- /* swap the pages */
- rb_init_page(bpage);
- bpage = reader->page;
- reader->page = *data_page;
- local_set(&reader->write, 0);
- local_set(&reader->entries, 0);
- reader->read = 0;
- *data_page = bpage;
-
- /*
- * Use the real_end for the data size,
- * This gives us a chance to store the lost events
- * on the page.
- */
- if (reader->real_end)
- local_set(&bpage->commit, reader->real_end);
- }
- ret = read;
-
- cpu_buffer->lost_events = 0;
-
- commit = local_read(&bpage->commit);
- /*
- * Set a flag in the commit field if we lost events
- */
- if (missed_events) {
- /* If there is room at the end of the page to save the
- * missed events, then record it there.
- */
- if (BUF_PAGE_SIZE - commit >= sizeof(missed_events)) {
- memcpy(&bpage->data[commit], &missed_events,
- sizeof(missed_events));
- local_add(RB_MISSED_STORED, &bpage->commit);
- commit += sizeof(missed_events);
- }
- local_add(RB_MISSED_EVENTS, &bpage->commit);
- }
-
- /*
- * This page may be off to user land. Zero it out here.
- */
- if (commit < BUF_PAGE_SIZE)
- memset(&bpage->data[commit], 0, BUF_PAGE_SIZE - commit);
-
- out_unlock:
- spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
-
- out:
- return ret;
-}
-EXPORT_SYMBOL_GPL(ring_buffer_read_page);
-
-#ifdef CONFIG_TRACING
-static ssize_t
-rb_simple_read(struct file *filp, char __user *ubuf,
- size_t cnt, loff_t *ppos)
-{
- unsigned long *p = filp->private_data;
- char buf[64];
- int r;
-
- if (test_bit(RB_BUFFERS_DISABLED_BIT, p))
- r = sprintf(buf, "permanently disabled\n");
- else
- r = sprintf(buf, "%d\n", test_bit(RB_BUFFERS_ON_BIT, p));
-
- return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
-}
-
-static ssize_t
-rb_simple_write(struct file *filp, const char __user *ubuf,
- size_t cnt, loff_t *ppos)
-{
- unsigned long *p = filp->private_data;
- char buf[64];
- unsigned long val;
- int ret;
-
- if (cnt >= sizeof(buf))
- return -EINVAL;
-
- if (copy_from_user(&buf, ubuf, cnt))
- return -EFAULT;
-
- buf[cnt] = 0;
-
- ret = strict_strtoul(buf, 10, &val);
- if (ret < 0)
- return ret;
-
- if (val)
- set_bit(RB_BUFFERS_ON_BIT, p);
- else
- clear_bit(RB_BUFFERS_ON_BIT, p);
-
- (*ppos)++;
-
- return cnt;
-}
-
-static const struct file_operations rb_simple_fops = {
- .open = tracing_open_generic,
- .read = rb_simple_read,
- .write = rb_simple_write,
-};
-
-
-static __init int rb_init_debugfs(void)
-{
- struct dentry *d_tracer;
-
- d_tracer = tracing_init_dentry();
-
- trace_create_file("tracing_on", 0644, d_tracer,
- &ring_buffer_flags, &rb_simple_fops);
-
- return 0;
-}
-
-fs_initcall(rb_init_debugfs);
-#endif
-
-#ifdef CONFIG_HOTPLUG_CPU
-static int rb_cpu_notify(struct notifier_block *self,
- unsigned long action, void *hcpu)
-{
- struct ring_buffer *buffer =
- container_of(self, struct ring_buffer, cpu_notify);
- long cpu = (long)hcpu;
-
- switch (action) {
- case CPU_UP_PREPARE:
- case CPU_UP_PREPARE_FROZEN:
- if (cpumask_test_cpu(cpu, buffer->cpumask))
- return NOTIFY_OK;
-
- buffer->buffers[cpu] =
- rb_allocate_cpu_buffer(buffer, cpu);
- if (!buffer->buffers[cpu]) {
- WARN(1, "failed to allocate ring buffer on CPU %ld\n",
- cpu);
- return NOTIFY_OK;
- }
- smp_wmb();
- cpumask_set_cpu(cpu, buffer->cpumask);
- break;
- case CPU_DOWN_PREPARE:
- case CPU_DOWN_PREPARE_FROZEN:
- /*
- * Do nothing.
- * If we were to free the buffer, then the user would
- * lose any trace that was in the buffer.
- */
- break;
- default:
- break;
- }
- return NOTIFY_OK;
-}
-#endif
Index: linux.trees.git/include/linux/oprofile.h
===================================================================
--- linux.trees.git.orig/include/linux/oprofile.h 2010-07-09 18:08:14.000000000 -0400
+++ linux.trees.git/include/linux/oprofile.h 2010-07-09 18:08:47.000000000 -0400
@@ -172,7 +172,7 @@ void oprofile_cpu_buffer_inc_smpl_lost(v
struct op_sample;
struct op_entry {
- struct ring_buffer_event *event;
+ struct ftrace_ring_buffer_event *event;
struct op_sample *sample;
unsigned long size;
unsigned long *data;
Index: linux.trees.git/include/trace/ftrace.h
===================================================================
--- linux.trees.git.orig/include/trace/ftrace.h 2010-07-09 18:08:14.000000000 -0400
+++ linux.trees.git/include/trace/ftrace.h 2010-07-09 18:08:47.000000000 -0400
@@ -399,9 +399,9 @@ static inline notrace int ftrace_get_off
* {
* struct ftrace_event_call *event_call = __data;
* struct ftrace_data_offsets_<call> __maybe_unused __data_offsets;
- * struct ring_buffer_event *event;
+ * struct ftrace_ring_buffer_event *event;
* struct ftrace_raw_<call> *entry; <-- defined in stage 1
- * struct ring_buffer *buffer;
+ * struct ftrace_ring_buffer *buffer;
* unsigned long irq_flags;
* int __data_size;
* int pc;
@@ -417,7 +417,7 @@ static inline notrace int ftrace_get_off
* irq_flags, pc);
* if (!event)
* return;
- * entry = ring_buffer_event_data(event);
+ * entry = ftrace_ring_buffer_event_data(event);
*
* { <assign>; } <-- Here we assign the entries by the __field and
* __array macros.
@@ -501,9 +501,9 @@ ftrace_raw_event_##call(void *__data, pr
{ \
struct ftrace_event_call *event_call = __data; \
struct ftrace_data_offsets_##call __maybe_unused __data_offsets;\
- struct ring_buffer_event *event; \
+ struct ftrace_ring_buffer_event *event; \
struct ftrace_raw_##call *entry; \
- struct ring_buffer *buffer; \
+ struct ftrace_ring_buffer *buffer; \
unsigned long irq_flags; \
int __data_size; \
int pc; \
@@ -519,7 +519,7 @@ ftrace_raw_event_##call(void *__data, pr
irq_flags, pc); \
if (!event) \
return; \
- entry = ring_buffer_event_data(event); \
+ entry = ftrace_ring_buffer_event_data(event); \
\
tstruct \
\
Index: linux.trees.git/kernel/trace/blktrace.c
===================================================================
--- linux.trees.git.orig/kernel/trace/blktrace.c 2010-07-09 18:08:14.000000000 -0400
+++ linux.trees.git/kernel/trace/blktrace.c 2010-07-09 18:08:47.000000000 -0400
@@ -65,8 +65,8 @@ static void trace_note(struct blk_trace
const void *data, size_t len)
{
struct blk_io_trace *t;
- struct ring_buffer_event *event = NULL;
- struct ring_buffer *buffer = NULL;
+ struct ftrace_ring_buffer_event *event = NULL;
+ struct ftrace_ring_buffer *buffer = NULL;
int pc = 0;
int cpu = smp_processor_id();
bool blk_tracer = blk_tracer_enabled;
@@ -79,7 +79,7 @@ static void trace_note(struct blk_trace
0, pc);
if (!event)
return;
- t = ring_buffer_event_data(event);
+ t = ftrace_ring_buffer_event_data(event);
goto record_it;
}
@@ -181,8 +181,8 @@ static void __blk_add_trace(struct blk_t
int rw, u32 what, int error, int pdu_len, void *pdu_data)
{
struct task_struct *tsk = current;
- struct ring_buffer_event *event = NULL;
- struct ring_buffer *buffer = NULL;
+ struct ftrace_ring_buffer_event *event = NULL;
+ struct ftrace_ring_buffer *buffer = NULL;
struct blk_io_trace *t;
unsigned long flags = 0;
unsigned long *sequence;
@@ -215,7 +215,7 @@ static void __blk_add_trace(struct blk_t
0, pc);
if (!event)
return;
- t = ring_buffer_event_data(event);
+ t = ftrace_ring_buffer_event_data(event);
goto record_it;
}
Index: linux.trees.git/kernel/trace/ftrace_ring_buffer_benchmark.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux.trees.git/kernel/trace/ftrace_ring_buffer_benchmark.c 2010-07-09 18:08:47.000000000 -0400
@@ -0,0 +1,488 @@
+/*
+ * ftrace ring buffer tester and benchmark
+ *
+ * Copyright (C) 2009 Steven Rostedt <srostedt@redhat.com>
+ */
+#include <linux/ftrace_ring_buffer.h>
+#include <linux/completion.h>
+#include <linux/kthread.h>
+#include <linux/module.h>
+#include <linux/time.h>
+#include <asm/local.h>
+
+struct rb_page {
+ u64 ts;
+ local_t commit;
+ char data[4080];
+};
+
+/* run time and sleep time in seconds */
+#define RUN_TIME 10
+#define SLEEP_TIME 10
+
+/* number of events for writer to wake up the reader */
+static int wakeup_interval = 100;
+
+static int reader_finish;
+static struct completion read_start;
+static struct completion read_done;
+
+static struct ftrace_ring_buffer *buffer;
+static struct task_struct *producer;
+static struct task_struct *consumer;
+static unsigned long read;
+
+static int disable_reader;
+module_param(disable_reader, uint, 0644);
+MODULE_PARM_DESC(disable_reader, "only run producer");
+
+static int write_iteration = 50;
+module_param(write_iteration, uint, 0644);
+MODULE_PARM_DESC(write_iteration, "# of writes between timestamp readings");
+
+static int producer_nice = 19;
+static int consumer_nice = 19;
+
+static int producer_fifo = -1;
+static int consumer_fifo = -1;
+
+module_param(producer_nice, uint, 0644);
+MODULE_PARM_DESC(producer_nice, "nice prio for producer");
+
+module_param(consumer_nice, uint, 0644);
+MODULE_PARM_DESC(consumer_nice, "nice prio for consumer");
+
+module_param(producer_fifo, uint, 0644);
+MODULE_PARM_DESC(producer_fifo, "fifo prio for producer");
+
+module_param(consumer_fifo, uint, 0644);
+MODULE_PARM_DESC(consumer_fifo, "fifo prio for consumer");
+
+static int read_events;
+
+static int kill_test;
+
+#define KILL_TEST() \
+ do { \
+ if (!kill_test) { \
+ kill_test = 1; \
+ WARN_ON(1); \
+ } \
+ } while (0)
+
+enum event_status {
+ EVENT_FOUND,
+ EVENT_DROPPED,
+};
+
+static enum event_status read_event(int cpu)
+{
+ struct ftrace_ring_buffer_event *event;
+ int *entry;
+ u64 ts;
+
+ event = ftrace_ring_buffer_consume(buffer, cpu, &ts, NULL);
+ if (!event)
+ return EVENT_DROPPED;
+
+ entry = ftrace_ring_buffer_event_data(event);
+ if (*entry != cpu) {
+ KILL_TEST();
+ return EVENT_DROPPED;
+ }
+
+ read++;
+ return EVENT_FOUND;
+}
+
+static enum event_status read_page(int cpu)
+{
+ struct ftrace_ring_buffer_event *event;
+ struct rb_page *rpage;
+ unsigned long commit;
+ void *bpage;
+ int *entry;
+ int ret;
+ int inc;
+ int i;
+
+ bpage = ftrace_ring_buffer_alloc_read_page(buffer);
+ if (!bpage)
+ return EVENT_DROPPED;
+
+ ret = ftrace_ring_buffer_read_page(buffer, &bpage, PAGE_SIZE, cpu, 1);
+ if (ret >= 0) {
+ rpage = bpage;
+ /* The commit may have missed event flags set, clear them */
+ commit = local_read(&rpage->commit) & 0xfffff;
+ for (i = 0; i < commit && !kill_test; i += inc) {
+
+ if (i >= (PAGE_SIZE - offsetof(struct rb_page, data))) {
+ KILL_TEST();
+ break;
+ }
+
+ inc = -1;
+ event = (void *)&rpage->data[i];
+ switch (event->type_len) {
+ case RINGBUF_TYPE_PADDING:
+ /* failed writes may be discarded events */
+ if (!event->time_delta)
+ KILL_TEST();
+ inc = event->array[0] + 4;
+ break;
+ case RINGBUF_TYPE_TIME_EXTEND:
+ inc = 8;
+ break;
+ case 0:
+ entry = ftrace_ring_buffer_event_data(event);
+ if (*entry != cpu) {
+ KILL_TEST();
+ break;
+ }
+ read++;
+ if (!event->array[0]) {
+ KILL_TEST();
+ break;
+ }
+ inc = event->array[0] + 4;
+ break;
+ default:
+ entry = ftrace_ring_buffer_event_data(event);
+ if (*entry != cpu) {
+ KILL_TEST();
+ break;
+ }
+ read++;
+ inc = ((event->type_len + 1) * 4);
+ }
+ if (kill_test)
+ break;
+
+ if (inc <= 0) {
+ KILL_TEST();
+ break;
+ }
+ }
+ }
+ ftrace_ring_buffer_free_read_page(buffer, bpage);
+
+ if (ret < 0)
+ return EVENT_DROPPED;
+ return EVENT_FOUND;
+}
+
+static void ftrace_ring_buffer_consumer(void)
+{
+ /* toggle between reading pages and events */
+ read_events ^= 1;
+
+ read = 0;
+ while (!reader_finish && !kill_test) {
+ int found;
+
+ do {
+ int cpu;
+
+ found = 0;
+ for_each_online_cpu(cpu) {
+ enum event_status stat;
+
+ if (read_events)
+ stat = read_event(cpu);
+ else
+ stat = read_page(cpu);
+
+ if (kill_test)
+ break;
+ if (stat == EVENT_FOUND)
+ found = 1;
+ }
+ } while (found && !kill_test);
+
+ set_current_state(TASK_INTERRUPTIBLE);
+ if (reader_finish)
+ break;
+
+ schedule();
+ __set_current_state(TASK_RUNNING);
+ }
+ reader_finish = 0;
+ complete(&read_done);
+}
+
+static void ftrace_ring_buffer_producer(void)
+{
+ struct timeval start_tv;
+ struct timeval end_tv;
+ unsigned long long time;
+ unsigned long long entries;
+ unsigned long long overruns;
+ unsigned long missed = 0;
+ unsigned long hit = 0;
+ unsigned long avg;
+ int cnt = 0;
+
+ /*
+ * Hammer the buffer for 10 secs (this may
+ * make the system stall)
+ */
+ trace_printk("Starting ring buffer hammer\n");
+ do_gettimeofday(&start_tv);
+ do {
+ struct ftrace_ring_buffer_event *event;
+ int *entry;
+ int i;
+
+ for (i = 0; i < write_iteration; i++) {
+ event = ftrace_ring_buffer_lock_reserve(buffer, 10);
+ if (!event) {
+ missed++;
+ } else {
+ hit++;
+ entry = ftrace_ring_buffer_event_data(event);
+ *entry = smp_processor_id();
+ ftrace_ring_buffer_unlock_commit(buffer, event);
+ }
+ }
+ do_gettimeofday(&end_tv);
+
+ cnt++;
+ if (consumer && !(cnt % wakeup_interval))
+ wake_up_process(consumer);
+
+#ifndef CONFIG_PREEMPT
+ /*
+ * If we are a non preempt kernel, the 10 second run will
+ * stop everything while it runs. Instead, we will call
+ * cond_resched and also add any time that was lost by a
+ * rescedule.
+ *
+ * Do a cond resched at the same frequency we would wake up
+ * the reader.
+ */
+ if (cnt % wakeup_interval)
+ cond_resched();
+#endif
+
+ } while (end_tv.tv_sec < (start_tv.tv_sec + RUN_TIME) && !kill_test);
+ trace_printk("End ring buffer hammer\n");
+
+ if (consumer) {
+ /* Init both completions here to avoid races */
+ init_completion(&read_start);
+ init_completion(&read_done);
+ /* the completions must be visible before the finish var */
+ smp_wmb();
+ reader_finish = 1;
+ /* finish var visible before waking up the consumer */
+ smp_wmb();
+ wake_up_process(consumer);
+ wait_for_completion(&read_done);
+ }
+
+ time = end_tv.tv_sec - start_tv.tv_sec;
+ time *= USEC_PER_SEC;
+ time += (long long)((long)end_tv.tv_usec - (long)start_tv.tv_usec);
+
+ entries = ftrace_ring_buffer_entries(buffer);
+ overruns = ftrace_ring_buffer_overruns(buffer);
+
+ if (kill_test)
+ trace_printk("ERROR!\n");
+
+ if (!disable_reader) {
+ if (consumer_fifo < 0)
+ trace_printk("Running Consumer at nice: %d\n",
+ consumer_nice);
+ else
+ trace_printk("Running Consumer at SCHED_FIFO %d\n",
+ consumer_fifo);
+ }
+ if (producer_fifo < 0)
+ trace_printk("Running Producer at nice: %d\n",
+ producer_nice);
+ else
+ trace_printk("Running Producer at SCHED_FIFO %d\n",
+ producer_fifo);
+
+ /* Let the user know that the test is running at low priority */
+ if (producer_fifo < 0 && consumer_fifo < 0 &&
+ producer_nice == 19 && consumer_nice == 19)
+ trace_printk("WARNING!!! This test is running at lowest priority.\n");
+
+ trace_printk("Time: %lld (usecs)\n", time);
+ trace_printk("Overruns: %lld\n", overruns);
+ if (disable_reader)
+ trace_printk("Read: (reader disabled)\n");
+ else
+ trace_printk("Read: %ld (by %s)\n", read,
+ read_events ? "events" : "pages");
+ trace_printk("Entries: %lld\n", entries);
+ trace_printk("Total: %lld\n", entries + overruns + read);
+ trace_printk("Missed: %ld\n", missed);
+ trace_printk("Hit: %ld\n", hit);
+
+ /* Convert time from usecs to millisecs */
+ do_div(time, USEC_PER_MSEC);
+ if (time)
+ hit /= (long)time;
+ else
+ trace_printk("TIME IS ZERO??\n");
+
+ trace_printk("Entries per millisec: %ld\n", hit);
+
+ if (hit) {
+ /* Calculate the average time in nanosecs */
+ avg = NSEC_PER_MSEC / hit;
+ trace_printk("%ld ns per entry\n", avg);
+ }
+
+ if (missed) {
+ if (time)
+ missed /= (long)time;
+
+ trace_printk("Total iterations per millisec: %ld\n",
+ hit + missed);
+
+ /* it is possible that hit + missed will overflow and be zero */
+ if (!(hit + missed)) {
+ trace_printk("hit + missed overflowed and totalled zero!\n");
+ hit--; /* make it non zero */
+ }
+
+ /* Caculate the average time in nanosecs */
+ avg = NSEC_PER_MSEC / (hit + missed);
+ trace_printk("%ld ns per entry\n", avg);
+ }
+}
+
+static void wait_to_die(void)
+{
+ set_current_state(TASK_INTERRUPTIBLE);
+ while (!kthread_should_stop()) {
+ schedule();
+ set_current_state(TASK_INTERRUPTIBLE);
+ }
+ __set_current_state(TASK_RUNNING);
+}
+
+static int ftrace_ring_buffer_consumer_thread(void *arg)
+{
+ while (!kthread_should_stop() && !kill_test) {
+ complete(&read_start);
+
+ ftrace_ring_buffer_consumer();
+
+ set_current_state(TASK_INTERRUPTIBLE);
+ if (kthread_should_stop() || kill_test)
+ break;
+
+ schedule();
+ __set_current_state(TASK_RUNNING);
+ }
+ __set_current_state(TASK_RUNNING);
+
+ if (kill_test)
+ wait_to_die();
+
+ return 0;
+}
+
+static int ftrace_ring_buffer_producer_thread(void *arg)
+{
+ init_completion(&read_start);
+
+ while (!kthread_should_stop() && !kill_test) {
+ ftrace_ring_buffer_reset(buffer);
+
+ if (consumer) {
+ smp_wmb();
+ wake_up_process(consumer);
+ wait_for_completion(&read_start);
+ }
+
+ ftrace_ring_buffer_producer();
+
+ trace_printk("Sleeping for 10 secs\n");
+ set_current_state(TASK_INTERRUPTIBLE);
+ schedule_timeout(HZ * SLEEP_TIME);
+ __set_current_state(TASK_RUNNING);
+ }
+
+ if (kill_test)
+ wait_to_die();
+
+ return 0;
+}
+
+static int __init ftrace_ring_buffer_benchmark_init(void)
+{
+ int ret;
+
+ /* make a one meg buffer in overwite mode */
+ buffer = ftrace_ring_buffer_alloc(1000000, RB_FL_OVERWRITE);
+ if (!buffer)
+ return -ENOMEM;
+
+ if (!disable_reader) {
+ consumer = kthread_create(ftrace_ring_buffer_consumer_thread,
+ NULL, "rb_consumer");
+ ret = PTR_ERR(consumer);
+ if (IS_ERR(consumer))
+ goto out_fail;
+ }
+
+ producer = kthread_run(ftrace_ring_buffer_producer_thread,
+ NULL, "rb_producer");
+ ret = PTR_ERR(producer);
+
+ if (IS_ERR(producer))
+ goto out_kill;
+
+ /*
+ * Run them as low-prio background tasks by default:
+ */
+ if (!disable_reader) {
+ if (consumer_fifo >= 0) {
+ struct sched_param param = {
+ .sched_priority = consumer_fifo
+ };
+ sched_setscheduler(consumer, SCHED_FIFO, ¶m);
+ } else
+ set_user_nice(consumer, consumer_nice);
+ }
+
+ if (producer_fifo >= 0) {
+ struct sched_param param = {
+ .sched_priority = consumer_fifo
+ };
+ sched_setscheduler(producer, SCHED_FIFO, ¶m);
+ } else
+ set_user_nice(producer, producer_nice);
+
+ return 0;
+
+ out_kill:
+ if (consumer)
+ kthread_stop(consumer);
+
+ out_fail:
+ ftrace_ring_buffer_free(buffer);
+ return ret;
+}
+
+static void __exit ftrace_ring_buffer_benchmark_exit(void)
+{
+ kthread_stop(producer);
+ if (consumer)
+ kthread_stop(consumer);
+ ftrace_ring_buffer_free(buffer);
+}
+
+module_init(ftrace_ring_buffer_benchmark_init);
+module_exit(ftrace_ring_buffer_benchmark_exit);
+
+MODULE_AUTHOR("Steven Rostedt");
+MODULE_DESCRIPTION("ftrace_ring_buffer_benchmark");
+MODULE_LICENSE("GPL");
Index: linux.trees.git/kernel/trace/ring_buffer_benchmark.c
===================================================================
--- linux.trees.git.orig/kernel/trace/ring_buffer_benchmark.c 2010-07-09 18:08:14.000000000 -0400
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1,488 +0,0 @@
-/*
- * ring buffer tester and benchmark
- *
- * Copyright (C) 2009 Steven Rostedt <srostedt@redhat.com>
- */
-#include <linux/ring_buffer.h>
-#include <linux/completion.h>
-#include <linux/kthread.h>
-#include <linux/module.h>
-#include <linux/time.h>
-#include <asm/local.h>
-
-struct rb_page {
- u64 ts;
- local_t commit;
- char data[4080];
-};
-
-/* run time and sleep time in seconds */
-#define RUN_TIME 10
-#define SLEEP_TIME 10
-
-/* number of events for writer to wake up the reader */
-static int wakeup_interval = 100;
-
-static int reader_finish;
-static struct completion read_start;
-static struct completion read_done;
-
-static struct ring_buffer *buffer;
-static struct task_struct *producer;
-static struct task_struct *consumer;
-static unsigned long read;
-
-static int disable_reader;
-module_param(disable_reader, uint, 0644);
-MODULE_PARM_DESC(disable_reader, "only run producer");
-
-static int write_iteration = 50;
-module_param(write_iteration, uint, 0644);
-MODULE_PARM_DESC(write_iteration, "# of writes between timestamp readings");
-
-static int producer_nice = 19;
-static int consumer_nice = 19;
-
-static int producer_fifo = -1;
-static int consumer_fifo = -1;
-
-module_param(producer_nice, uint, 0644);
-MODULE_PARM_DESC(producer_nice, "nice prio for producer");
-
-module_param(consumer_nice, uint, 0644);
-MODULE_PARM_DESC(consumer_nice, "nice prio for consumer");
-
-module_param(producer_fifo, uint, 0644);
-MODULE_PARM_DESC(producer_fifo, "fifo prio for producer");
-
-module_param(consumer_fifo, uint, 0644);
-MODULE_PARM_DESC(consumer_fifo, "fifo prio for consumer");
-
-static int read_events;
-
-static int kill_test;
-
-#define KILL_TEST() \
- do { \
- if (!kill_test) { \
- kill_test = 1; \
- WARN_ON(1); \
- } \
- } while (0)
-
-enum event_status {
- EVENT_FOUND,
- EVENT_DROPPED,
-};
-
-static enum event_status read_event(int cpu)
-{
- struct ring_buffer_event *event;
- int *entry;
- u64 ts;
-
- event = ring_buffer_consume(buffer, cpu, &ts, NULL);
- if (!event)
- return EVENT_DROPPED;
-
- entry = ring_buffer_event_data(event);
- if (*entry != cpu) {
- KILL_TEST();
- return EVENT_DROPPED;
- }
-
- read++;
- return EVENT_FOUND;
-}
-
-static enum event_status read_page(int cpu)
-{
- struct ring_buffer_event *event;
- struct rb_page *rpage;
- unsigned long commit;
- void *bpage;
- int *entry;
- int ret;
- int inc;
- int i;
-
- bpage = ring_buffer_alloc_read_page(buffer);
- if (!bpage)
- return EVENT_DROPPED;
-
- ret = ring_buffer_read_page(buffer, &bpage, PAGE_SIZE, cpu, 1);
- if (ret >= 0) {
- rpage = bpage;
- /* The commit may have missed event flags set, clear them */
- commit = local_read(&rpage->commit) & 0xfffff;
- for (i = 0; i < commit && !kill_test; i += inc) {
-
- if (i >= (PAGE_SIZE - offsetof(struct rb_page, data))) {
- KILL_TEST();
- break;
- }
-
- inc = -1;
- event = (void *)&rpage->data[i];
- switch (event->type_len) {
- case RINGBUF_TYPE_PADDING:
- /* failed writes may be discarded events */
- if (!event->time_delta)
- KILL_TEST();
- inc = event->array[0] + 4;
- break;
- case RINGBUF_TYPE_TIME_EXTEND:
- inc = 8;
- break;
- case 0:
- entry = ring_buffer_event_data(event);
- if (*entry != cpu) {
- KILL_TEST();
- break;
- }
- read++;
- if (!event->array[0]) {
- KILL_TEST();
- break;
- }
- inc = event->array[0] + 4;
- break;
- default:
- entry = ring_buffer_event_data(event);
- if (*entry != cpu) {
- KILL_TEST();
- break;
- }
- read++;
- inc = ((event->type_len + 1) * 4);
- }
- if (kill_test)
- break;
-
- if (inc <= 0) {
- KILL_TEST();
- break;
- }
- }
- }
- ring_buffer_free_read_page(buffer, bpage);
-
- if (ret < 0)
- return EVENT_DROPPED;
- return EVENT_FOUND;
-}
-
-static void ring_buffer_consumer(void)
-{
- /* toggle between reading pages and events */
- read_events ^= 1;
-
- read = 0;
- while (!reader_finish && !kill_test) {
- int found;
-
- do {
- int cpu;
-
- found = 0;
- for_each_online_cpu(cpu) {
- enum event_status stat;
-
- if (read_events)
- stat = read_event(cpu);
- else
- stat = read_page(cpu);
-
- if (kill_test)
- break;
- if (stat == EVENT_FOUND)
- found = 1;
- }
- } while (found && !kill_test);
-
- set_current_state(TASK_INTERRUPTIBLE);
- if (reader_finish)
- break;
-
- schedule();
- __set_current_state(TASK_RUNNING);
- }
- reader_finish = 0;
- complete(&read_done);
-}
-
-static void ring_buffer_producer(void)
-{
- struct timeval start_tv;
- struct timeval end_tv;
- unsigned long long time;
- unsigned long long entries;
- unsigned long long overruns;
- unsigned long missed = 0;
- unsigned long hit = 0;
- unsigned long avg;
- int cnt = 0;
-
- /*
- * Hammer the buffer for 10 secs (this may
- * make the system stall)
- */
- trace_printk("Starting ring buffer hammer\n");
- do_gettimeofday(&start_tv);
- do {
- struct ring_buffer_event *event;
- int *entry;
- int i;
-
- for (i = 0; i < write_iteration; i++) {
- event = ring_buffer_lock_reserve(buffer, 10);
- if (!event) {
- missed++;
- } else {
- hit++;
- entry = ring_buffer_event_data(event);
- *entry = smp_processor_id();
- ring_buffer_unlock_commit(buffer, event);
- }
- }
- do_gettimeofday(&end_tv);
-
- cnt++;
- if (consumer && !(cnt % wakeup_interval))
- wake_up_process(consumer);
-
-#ifndef CONFIG_PREEMPT
- /*
- * If we are a non preempt kernel, the 10 second run will
- * stop everything while it runs. Instead, we will call
- * cond_resched and also add any time that was lost by a
- * rescedule.
- *
- * Do a cond resched at the same frequency we would wake up
- * the reader.
- */
- if (cnt % wakeup_interval)
- cond_resched();
-#endif
-
- } while (end_tv.tv_sec < (start_tv.tv_sec + RUN_TIME) && !kill_test);
- trace_printk("End ring buffer hammer\n");
-
- if (consumer) {
- /* Init both completions here to avoid races */
- init_completion(&read_start);
- init_completion(&read_done);
- /* the completions must be visible before the finish var */
- smp_wmb();
- reader_finish = 1;
- /* finish var visible before waking up the consumer */
- smp_wmb();
- wake_up_process(consumer);
- wait_for_completion(&read_done);
- }
-
- time = end_tv.tv_sec - start_tv.tv_sec;
- time *= USEC_PER_SEC;
- time += (long long)((long)end_tv.tv_usec - (long)start_tv.tv_usec);
-
- entries = ring_buffer_entries(buffer);
- overruns = ring_buffer_overruns(buffer);
-
- if (kill_test)
- trace_printk("ERROR!\n");
-
- if (!disable_reader) {
- if (consumer_fifo < 0)
- trace_printk("Running Consumer at nice: %d\n",
- consumer_nice);
- else
- trace_printk("Running Consumer at SCHED_FIFO %d\n",
- consumer_fifo);
- }
- if (producer_fifo < 0)
- trace_printk("Running Producer at nice: %d\n",
- producer_nice);
- else
- trace_printk("Running Producer at SCHED_FIFO %d\n",
- producer_fifo);
-
- /* Let the user know that the test is running at low priority */
- if (producer_fifo < 0 && consumer_fifo < 0 &&
- producer_nice == 19 && consumer_nice == 19)
- trace_printk("WARNING!!! This test is running at lowest priority.\n");
-
- trace_printk("Time: %lld (usecs)\n", time);
- trace_printk("Overruns: %lld\n", overruns);
- if (disable_reader)
- trace_printk("Read: (reader disabled)\n");
- else
- trace_printk("Read: %ld (by %s)\n", read,
- read_events ? "events" : "pages");
- trace_printk("Entries: %lld\n", entries);
- trace_printk("Total: %lld\n", entries + overruns + read);
- trace_printk("Missed: %ld\n", missed);
- trace_printk("Hit: %ld\n", hit);
-
- /* Convert time from usecs to millisecs */
- do_div(time, USEC_PER_MSEC);
- if (time)
- hit /= (long)time;
- else
- trace_printk("TIME IS ZERO??\n");
-
- trace_printk("Entries per millisec: %ld\n", hit);
-
- if (hit) {
- /* Calculate the average time in nanosecs */
- avg = NSEC_PER_MSEC / hit;
- trace_printk("%ld ns per entry\n", avg);
- }
-
- if (missed) {
- if (time)
- missed /= (long)time;
-
- trace_printk("Total iterations per millisec: %ld\n",
- hit + missed);
-
- /* it is possible that hit + missed will overflow and be zero */
- if (!(hit + missed)) {
- trace_printk("hit + missed overflowed and totalled zero!\n");
- hit--; /* make it non zero */
- }
-
- /* Caculate the average time in nanosecs */
- avg = NSEC_PER_MSEC / (hit + missed);
- trace_printk("%ld ns per entry\n", avg);
- }
-}
-
-static void wait_to_die(void)
-{
- set_current_state(TASK_INTERRUPTIBLE);
- while (!kthread_should_stop()) {
- schedule();
- set_current_state(TASK_INTERRUPTIBLE);
- }
- __set_current_state(TASK_RUNNING);
-}
-
-static int ring_buffer_consumer_thread(void *arg)
-{
- while (!kthread_should_stop() && !kill_test) {
- complete(&read_start);
-
- ring_buffer_consumer();
-
- set_current_state(TASK_INTERRUPTIBLE);
- if (kthread_should_stop() || kill_test)
- break;
-
- schedule();
- __set_current_state(TASK_RUNNING);
- }
- __set_current_state(TASK_RUNNING);
-
- if (kill_test)
- wait_to_die();
-
- return 0;
-}
-
-static int ring_buffer_producer_thread(void *arg)
-{
- init_completion(&read_start);
-
- while (!kthread_should_stop() && !kill_test) {
- ring_buffer_reset(buffer);
-
- if (consumer) {
- smp_wmb();
- wake_up_process(consumer);
- wait_for_completion(&read_start);
- }
-
- ring_buffer_producer();
-
- trace_printk("Sleeping for 10 secs\n");
- set_current_state(TASK_INTERRUPTIBLE);
- schedule_timeout(HZ * SLEEP_TIME);
- __set_current_state(TASK_RUNNING);
- }
-
- if (kill_test)
- wait_to_die();
-
- return 0;
-}
-
-static int __init ring_buffer_benchmark_init(void)
-{
- int ret;
-
- /* make a one meg buffer in overwite mode */
- buffer = ring_buffer_alloc(1000000, RB_FL_OVERWRITE);
- if (!buffer)
- return -ENOMEM;
-
- if (!disable_reader) {
- consumer = kthread_create(ring_buffer_consumer_thread,
- NULL, "rb_consumer");
- ret = PTR_ERR(consumer);
- if (IS_ERR(consumer))
- goto out_fail;
- }
-
- producer = kthread_run(ring_buffer_producer_thread,
- NULL, "rb_producer");
- ret = PTR_ERR(producer);
-
- if (IS_ERR(producer))
- goto out_kill;
-
- /*
- * Run them as low-prio background tasks by default:
- */
- if (!disable_reader) {
- if (consumer_fifo >= 0) {
- struct sched_param param = {
- .sched_priority = consumer_fifo
- };
- sched_setscheduler(consumer, SCHED_FIFO, ¶m);
- } else
- set_user_nice(consumer, consumer_nice);
- }
-
- if (producer_fifo >= 0) {
- struct sched_param param = {
- .sched_priority = consumer_fifo
- };
- sched_setscheduler(producer, SCHED_FIFO, ¶m);
- } else
- set_user_nice(producer, producer_nice);
-
- return 0;
-
- out_kill:
- if (consumer)
- kthread_stop(consumer);
-
- out_fail:
- ring_buffer_free(buffer);
- return ret;
-}
-
-static void __exit ring_buffer_benchmark_exit(void)
-{
- kthread_stop(producer);
- if (consumer)
- kthread_stop(consumer);
- ring_buffer_free(buffer);
-}
-
-module_init(ring_buffer_benchmark_init);
-module_exit(ring_buffer_benchmark_exit);
-
-MODULE_AUTHOR("Steven Rostedt");
-MODULE_DESCRIPTION("ring_buffer_benchmark");
-MODULE_LICENSE("GPL");
Index: linux.trees.git/kernel/trace/trace.c
===================================================================
--- linux.trees.git.orig/kernel/trace/trace.c 2010-07-09 18:08:14.000000000 -0400
+++ linux.trees.git/kernel/trace/trace.c 2010-07-09 18:08:47.000000000 -0400
@@ -11,7 +11,7 @@
* Copyright (C) 2004-2006 Ingo Molnar
* Copyright (C) 2004 William Lee Irwin III
*/
-#include <linux/ring_buffer.h>
+#include <linux/ftrace_ring_buffer.h>
#include <generated/utsrelease.h>
#include <linux/stacktrace.h>
#include <linux/writeback.h>
@@ -48,7 +48,7 @@
* On boot up, the ring buffer is set to the minimum size, so that
* we do not waste memory on systems that are not using tracing.
*/
-int ring_buffer_expanded;
+int ftrace_ring_buffer_expanded;
/*
* We need to change this state when a selftest is running.
@@ -135,7 +135,7 @@ static int __init set_cmdline_ftrace(cha
strncpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
default_bootup_tracer = bootup_tracer_buf;
/* We are using ftrace early, expand it */
- ring_buffer_expanded = 1;
+ ftrace_ring_buffer_expanded = 1;
return 1;
}
__setup("ftrace=", set_cmdline_ftrace);
@@ -179,9 +179,9 @@ static struct trace_array global_trace;
static DEFINE_PER_CPU(struct trace_array_cpu, global_trace_cpu);
-int filter_current_check_discard(struct ring_buffer *buffer,
+int filter_current_check_discard(struct ftrace_ring_buffer *buffer,
struct ftrace_event_call *call, void *rec,
- struct ring_buffer_event *event)
+ struct ftrace_ring_buffer_event *event)
{
return filter_check_discard(call, rec, buffer, event);
}
@@ -195,8 +195,8 @@ cycle_t ftrace_now(int cpu)
if (!global_trace.buffer)
return trace_clock_local();
- ts = ring_buffer_time_stamp(global_trace.buffer, cpu);
- ring_buffer_normalize_time_stamp(global_trace.buffer, cpu, &ts);
+ ts = ftrace_ring_buffer_time_stamp(global_trace.buffer, cpu);
+ ftrace_ring_buffer_normalize_time_stamp(global_trace.buffer, cpu, &ts);
return ts;
}
@@ -260,7 +260,7 @@ static DEFINE_MUTEX(trace_types_lock);
* serialize the access of the ring buffer
*
* ring buffer serializes readers, but it is low level protection.
- * The validity of the events (which returns by ring_buffer_peek() ..etc)
+ * The validity of the events (which returns by ftrace_ring_buffer_peek() ..etc)
* are not protected by ring buffer.
*
* The content of events may become garbage if we allow other process consumes
@@ -653,7 +653,7 @@ __update_max_tr(struct trace_array *tr,
void
update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
{
- struct ring_buffer *buf = tr->buffer;
+ struct ftrace_ring_buffer *buf = tr->buffer;
if (trace_stop_count)
return;
@@ -689,7 +689,7 @@ update_max_tr_single(struct trace_array
ftrace_disable_cpu();
- ret = ring_buffer_swap_cpu(max_tr.buffer, tr->buffer, cpu);
+ ret = ftrace_ring_buffer_swap_cpu(max_tr.buffer, tr->buffer, cpu);
if (ret == -EBUSY) {
/*
@@ -852,32 +852,32 @@ out:
mutex_unlock(&trace_types_lock);
}
-static void __tracing_reset(struct ring_buffer *buffer, int cpu)
+static void __tracing_reset(struct ftrace_ring_buffer *buffer, int cpu)
{
ftrace_disable_cpu();
- ring_buffer_reset_cpu(buffer, cpu);
+ ftrace_ring_buffer_reset_cpu(buffer, cpu);
ftrace_enable_cpu();
}
void tracing_reset(struct trace_array *tr, int cpu)
{
- struct ring_buffer *buffer = tr->buffer;
+ struct ftrace_ring_buffer *buffer = tr->buffer;
- ring_buffer_record_disable(buffer);
+ ftrace_ring_buffer_record_disable(buffer);
/* Make sure all commits have finished */
synchronize_sched();
__tracing_reset(buffer, cpu);
- ring_buffer_record_enable(buffer);
+ ftrace_ring_buffer_record_enable(buffer);
}
void tracing_reset_online_cpus(struct trace_array *tr)
{
- struct ring_buffer *buffer = tr->buffer;
+ struct ftrace_ring_buffer *buffer = tr->buffer;
int cpu;
- ring_buffer_record_disable(buffer);
+ ftrace_ring_buffer_record_disable(buffer);
/* Make sure all commits have finished */
synchronize_sched();
@@ -887,7 +887,7 @@ void tracing_reset_online_cpus(struct tr
for_each_online_cpu(cpu)
__tracing_reset(buffer, cpu);
- ring_buffer_record_enable(buffer);
+ ftrace_ring_buffer_record_enable(buffer);
}
void tracing_reset_current(int cpu)
@@ -946,7 +946,7 @@ void ftrace_off_permanent(void)
*/
void tracing_start(void)
{
- struct ring_buffer *buffer;
+ struct ftrace_ring_buffer *buffer;
unsigned long flags;
if (tracing_disabled)
@@ -967,11 +967,11 @@ void tracing_start(void)
buffer = global_trace.buffer;
if (buffer)
- ring_buffer_record_enable(buffer);
+ ftrace_ring_buffer_record_enable(buffer);
buffer = max_tr.buffer;
if (buffer)
- ring_buffer_record_enable(buffer);
+ ftrace_ring_buffer_record_enable(buffer);
arch_spin_unlock(&ftrace_max_lock);
@@ -988,7 +988,7 @@ void tracing_start(void)
*/
void tracing_stop(void)
{
- struct ring_buffer *buffer;
+ struct ftrace_ring_buffer *buffer;
unsigned long flags;
ftrace_stop();
@@ -1001,11 +1001,11 @@ void tracing_stop(void)
buffer = global_trace.buffer;
if (buffer)
- ring_buffer_record_disable(buffer);
+ ftrace_ring_buffer_record_disable(buffer);
buffer = max_tr.buffer;
if (buffer)
- ring_buffer_record_disable(buffer);
+ ftrace_ring_buffer_record_disable(buffer);
arch_spin_unlock(&ftrace_max_lock);
@@ -1117,17 +1117,17 @@ tracing_generic_entry_update(struct trac
}
EXPORT_SYMBOL_GPL(tracing_generic_entry_update);
-struct ring_buffer_event *
-trace_buffer_lock_reserve(struct ring_buffer *buffer,
+struct ftrace_ring_buffer_event *
+trace_buffer_lock_reserve(struct ftrace_ring_buffer *buffer,
int type,
unsigned long len,
unsigned long flags, int pc)
{
- struct ring_buffer_event *event;
+ struct ftrace_ring_buffer_event *event;
- event = ring_buffer_lock_reserve(buffer, len);
+ event = ftrace_ring_buffer_lock_reserve(buffer, len);
if (event != NULL) {
- struct trace_entry *ent = ring_buffer_event_data(event);
+ struct trace_entry *ent = ftrace_ring_buffer_event_data(event);
tracing_generic_entry_update(ent, flags, pc);
ent->type = type;
@@ -1137,12 +1137,12 @@ trace_buffer_lock_reserve(struct ring_bu
}
static inline void
-__trace_buffer_unlock_commit(struct ring_buffer *buffer,
- struct ring_buffer_event *event,
+__trace_buffer_unlock_commit(struct ftrace_ring_buffer *buffer,
+ struct ftrace_ring_buffer_event *event,
unsigned long flags, int pc,
int wake)
{
- ring_buffer_unlock_commit(buffer, event);
+ ftrace_ring_buffer_unlock_commit(buffer, event);
ftrace_trace_stack(buffer, flags, 6, pc);
ftrace_trace_userstack(buffer, flags, pc);
@@ -1151,15 +1151,15 @@ __trace_buffer_unlock_commit(struct ring
trace_wake_up();
}
-void trace_buffer_unlock_commit(struct ring_buffer *buffer,
- struct ring_buffer_event *event,
+void trace_buffer_unlock_commit(struct ftrace_ring_buffer *buffer,
+ struct ftrace_ring_buffer_event *event,
unsigned long flags, int pc)
{
__trace_buffer_unlock_commit(buffer, event, flags, pc, 1);
}
-struct ring_buffer_event *
-trace_current_buffer_lock_reserve(struct ring_buffer **current_rb,
+struct ftrace_ring_buffer_event *
+trace_current_buffer_lock_reserve(struct ftrace_ring_buffer **current_rb,
int type, unsigned long len,
unsigned long flags, int pc)
{
@@ -1169,26 +1169,26 @@ trace_current_buffer_lock_reserve(struct
}
EXPORT_SYMBOL_GPL(trace_current_buffer_lock_reserve);
-void trace_current_buffer_unlock_commit(struct ring_buffer *buffer,
- struct ring_buffer_event *event,
+void trace_current_buffer_unlock_commit(struct ftrace_ring_buffer *buffer,
+ struct ftrace_ring_buffer_event *event,
unsigned long flags, int pc)
{
__trace_buffer_unlock_commit(buffer, event, flags, pc, 1);
}
EXPORT_SYMBOL_GPL(trace_current_buffer_unlock_commit);
-void trace_nowake_buffer_unlock_commit(struct ring_buffer *buffer,
- struct ring_buffer_event *event,
+void trace_nowake_buffer_unlock_commit(struct ftrace_ring_buffer *buffer,
+ struct ftrace_ring_buffer_event *event,
unsigned long flags, int pc)
{
__trace_buffer_unlock_commit(buffer, event, flags, pc, 0);
}
EXPORT_SYMBOL_GPL(trace_nowake_buffer_unlock_commit);
-void trace_current_buffer_discard_commit(struct ring_buffer *buffer,
- struct ring_buffer_event *event)
+void trace_current_buffer_discard_commit(struct ftrace_ring_buffer *buffer,
+ struct ftrace_ring_buffer_event *event)
{
- ring_buffer_discard_commit(buffer, event);
+ ftrace_ring_buffer_discard_commit(buffer, event);
}
EXPORT_SYMBOL_GPL(trace_current_buffer_discard_commit);
@@ -1198,8 +1198,8 @@ trace_function(struct trace_array *tr,
int pc)
{
struct ftrace_event_call *call = &event_function;
- struct ring_buffer *buffer = tr->buffer;
- struct ring_buffer_event *event;
+ struct ftrace_ring_buffer *buffer = tr->buffer;
+ struct ftrace_ring_buffer_event *event;
struct ftrace_entry *entry;
/* If we are reading the ring buffer, don't trace */
@@ -1210,12 +1210,12 @@ trace_function(struct trace_array *tr,
flags, pc);
if (!event)
return;
- entry = ring_buffer_event_data(event);
+ entry = ftrace_ring_buffer_event_data(event);
entry->ip = ip;
entry->parent_ip = parent_ip;
if (!filter_check_discard(call, entry, buffer, event))
- ring_buffer_unlock_commit(buffer, event);
+ ftrace_ring_buffer_unlock_commit(buffer, event);
}
void
@@ -1228,12 +1228,12 @@ ftrace(struct trace_array *tr, struct tr
}
#ifdef CONFIG_STACKTRACE
-static void __ftrace_trace_stack(struct ring_buffer *buffer,
+static void __ftrace_trace_stack(struct ftrace_ring_buffer *buffer,
unsigned long flags,
int skip, int pc)
{
struct ftrace_event_call *call = &event_kernel_stack;
- struct ring_buffer_event *event;
+ struct ftrace_ring_buffer_event *event;
struct stack_entry *entry;
struct stack_trace trace;
@@ -1241,7 +1241,7 @@ static void __ftrace_trace_stack(struct
sizeof(*entry), flags, pc);
if (!event)
return;
- entry = ring_buffer_event_data(event);
+ entry = ftrace_ring_buffer_event_data(event);
memset(&entry->caller, 0, sizeof(entry->caller));
trace.nr_entries = 0;
@@ -1251,10 +1251,10 @@ static void __ftrace_trace_stack(struct
save_stack_trace(&trace);
if (!filter_check_discard(call, entry, buffer, event))
- ring_buffer_unlock_commit(buffer, event);
+ ftrace_ring_buffer_unlock_commit(buffer, event);
}
-void ftrace_trace_stack(struct ring_buffer *buffer, unsigned long flags,
+void ftrace_trace_stack(struct ftrace_ring_buffer *buffer, unsigned long flags,
int skip, int pc)
{
if (!(trace_flags & TRACE_ITER_STACKTRACE))
@@ -1286,10 +1286,10 @@ void trace_dump_stack(void)
}
void
-ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
+ftrace_trace_userstack(struct ftrace_ring_buffer *buffer, unsigned long flags, int pc)
{
struct ftrace_event_call *call = &event_user_stack;
- struct ring_buffer_event *event;
+ struct ftrace_ring_buffer_event *event;
struct userstack_entry *entry;
struct stack_trace trace;
@@ -1307,7 +1307,7 @@ ftrace_trace_userstack(struct ring_buffe
sizeof(*entry), flags, pc);
if (!event)
return;
- entry = ring_buffer_event_data(event);
+ entry = ftrace_ring_buffer_event_data(event);
entry->tgid = current->tgid;
memset(&entry->caller, 0, sizeof(entry->caller));
@@ -1319,7 +1319,7 @@ ftrace_trace_userstack(struct ring_buffe
save_stack_trace_user(&trace);
if (!filter_check_discard(call, entry, buffer, event))
- ring_buffer_unlock_commit(buffer, event);
+ ftrace_ring_buffer_unlock_commit(buffer, event);
}
#ifdef UNUSED
@@ -1337,16 +1337,16 @@ ftrace_trace_special(void *__tr,
int pc)
{
struct ftrace_event_call *call = &event_special;
- struct ring_buffer_event *event;
+ struct ftrace_ring_buffer_event *event;
struct trace_array *tr = __tr;
- struct ring_buffer *buffer = tr->buffer;
+ struct ftrace_ring_buffer *buffer = tr->buffer;
struct special_entry *entry;
event = trace_buffer_lock_reserve(buffer, TRACE_SPECIAL,
sizeof(*entry), 0, pc);
if (!event)
return;
- entry = ring_buffer_event_data(event);
+ entry = ftrace_ring_buffer_event_data(event);
entry->arg1 = arg1;
entry->arg2 = arg2;
entry->arg3 = arg3;
@@ -1397,8 +1397,8 @@ int trace_vbprintk(unsigned long ip, con
static u32 trace_buf[TRACE_BUF_SIZE];
struct ftrace_event_call *call = &event_bprint;
- struct ring_buffer_event *event;
- struct ring_buffer *buffer;
+ struct ftrace_ring_buffer_event *event;
+ struct ftrace_ring_buffer *buffer;
struct trace_array *tr = &global_trace;
struct trace_array_cpu *data;
struct bprint_entry *entry;
@@ -1435,13 +1435,13 @@ int trace_vbprintk(unsigned long ip, con
flags, pc);
if (!event)
goto out_unlock;
- entry = ring_buffer_event_data(event);
+ entry = ftrace_ring_buffer_event_data(event);
entry->ip = ip;
entry->fmt = fmt;
memcpy(entry->buf, trace_buf, sizeof(u32) * len);
if (!filter_check_discard(call, entry, buffer, event)) {
- ring_buffer_unlock_commit(buffer, event);
+ ftrace_ring_buffer_unlock_commit(buffer, event);
ftrace_trace_stack(buffer, flags, 6, pc);
}
@@ -1480,8 +1480,8 @@ int trace_array_vprintk(struct trace_arr
static char trace_buf[TRACE_BUF_SIZE];
struct ftrace_event_call *call = &event_print;
- struct ring_buffer_event *event;
- struct ring_buffer *buffer;
+ struct ftrace_ring_buffer_event *event;
+ struct ftrace_ring_buffer *buffer;
struct trace_array_cpu *data;
int cpu, len = 0, size, pc;
struct print_entry *entry;
@@ -1511,13 +1511,13 @@ int trace_array_vprintk(struct trace_arr
irq_flags, pc);
if (!event)
goto out_unlock;
- entry = ring_buffer_event_data(event);
+ entry = ftrace_ring_buffer_event_data(event);
entry->ip = ip;
memcpy(&entry->buf, trace_buf, len);
entry->buf[len] = '\0';
if (!filter_check_discard(call, entry, buffer, event)) {
- ring_buffer_unlock_commit(buffer, event);
+ ftrace_ring_buffer_unlock_commit(buffer, event);
ftrace_trace_stack(buffer, irq_flags, 6, pc);
}
@@ -1550,7 +1550,7 @@ static void trace_iterator_increment(str
iter->idx++;
if (iter->buffer_iter[iter->cpu])
- ring_buffer_read(iter->buffer_iter[iter->cpu], NULL);
+ ftrace_ring_buffer_read(iter->buffer_iter[iter->cpu], NULL);
ftrace_enable_cpu();
}
@@ -1559,28 +1559,28 @@ static struct trace_entry *
peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts,
unsigned long *lost_events)
{
- struct ring_buffer_event *event;
- struct ring_buffer_iter *buf_iter = iter->buffer_iter[cpu];
+ struct ftrace_ring_buffer_event *event;
+ struct ftrace_ring_buffer_iter *buf_iter = iter->buffer_iter[cpu];
/* Don't allow ftrace to trace into the ring buffers */
ftrace_disable_cpu();
if (buf_iter)
- event = ring_buffer_iter_peek(buf_iter, ts);
+ event = ftrace_ring_buffer_iter_peek(buf_iter, ts);
else
- event = ring_buffer_peek(iter->tr->buffer, cpu, ts,
+ event = ftrace_ring_buffer_peek(iter->tr->buffer, cpu, ts,
lost_events);
ftrace_enable_cpu();
- return event ? ring_buffer_event_data(event) : NULL;
+ return event ? ftrace_ring_buffer_event_data(event) : NULL;
}
static struct trace_entry *
__find_next_entry(struct trace_iterator *iter, int *ent_cpu,
unsigned long *missing_events, u64 *ent_ts)
{
- struct ring_buffer *buffer = iter->tr->buffer;
+ struct ftrace_ring_buffer *buffer = iter->tr->buffer;
struct trace_entry *ent, *next = NULL;
unsigned long lost_events = 0, next_lost = 0;
int cpu_file = iter->cpu_file;
@@ -1593,7 +1593,7 @@ __find_next_entry(struct trace_iterator
* all cpu and peek directly.
*/
if (cpu_file > TRACE_PIPE_ALL_CPU) {
- if (ring_buffer_empty_cpu(buffer, cpu_file))
+ if (ftrace_ring_buffer_empty_cpu(buffer, cpu_file))
return NULL;
ent = peek_next_entry(iter, cpu_file, ent_ts, missing_events);
if (ent_cpu)
@@ -1604,7 +1604,7 @@ __find_next_entry(struct trace_iterator
for_each_tracing_cpu(cpu) {
- if (ring_buffer_empty_cpu(buffer, cpu))
+ if (ftrace_ring_buffer_empty_cpu(buffer, cpu))
continue;
ent = peek_next_entry(iter, cpu, &ts, &lost_events);
@@ -1655,7 +1655,7 @@ static void trace_consume(struct trace_i
{
/* Don't allow ftrace to trace into the ring buffers */
ftrace_disable_cpu();
- ring_buffer_consume(iter->tr->buffer, iter->cpu, &iter->ts,
+ ftrace_ring_buffer_consume(iter->tr->buffer, iter->cpu, &iter->ts,
&iter->lost_events);
ftrace_enable_cpu();
}
@@ -1690,8 +1690,8 @@ static void *s_next(struct seq_file *m,
static void tracing_iter_reset(struct trace_iterator *iter, int cpu)
{
struct trace_array *tr = iter->tr;
- struct ring_buffer_event *event;
- struct ring_buffer_iter *buf_iter;
+ struct ftrace_ring_buffer_event *event;
+ struct ftrace_ring_buffer_iter *buf_iter;
unsigned long entries = 0;
u64 ts;
@@ -1701,18 +1701,18 @@ static void tracing_iter_reset(struct tr
return;
buf_iter = iter->buffer_iter[cpu];
- ring_buffer_iter_reset(buf_iter);
+ ftrace_ring_buffer_iter_reset(buf_iter);
/*
* We could have the case with the max latency tracers
* that a reset never took place on a cpu. This is evident
* by the timestamp being before the start of the buffer.
*/
- while ((event = ring_buffer_iter_peek(buf_iter, &ts))) {
+ while ((event = ftrace_ring_buffer_iter_peek(buf_iter, &ts))) {
if (ts >= iter->tr->time_start)
break;
entries++;
- ring_buffer_read(buf_iter, NULL);
+ ftrace_ring_buffer_read(buf_iter, NULL);
}
tr->data[cpu]->skipped_entries = entries;
@@ -1825,7 +1825,7 @@ print_trace_header(struct seq_file *m, s
for_each_tracing_cpu(cpu) {
- count = ring_buffer_entries_cpu(tr->buffer, cpu);
+ count = ftrace_ring_buffer_entries_cpu(tr->buffer, cpu);
/*
* If this buffer has skipped entries, then we hold all
* entries for the trace and we need to ignore the
@@ -1837,7 +1837,7 @@ print_trace_header(struct seq_file *m, s
total += count;
} else
total += count +
- ring_buffer_overrun_cpu(tr->buffer, cpu);
+ ftrace_ring_buffer_overrun_cpu(tr->buffer, cpu);
entries += count;
}
@@ -2025,10 +2025,10 @@ int trace_empty(struct trace_iterator *i
if (iter->cpu_file != TRACE_PIPE_ALL_CPU) {
cpu = iter->cpu_file;
if (iter->buffer_iter[cpu]) {
- if (!ring_buffer_iter_empty(iter->buffer_iter[cpu]))
+ if (!ftrace_ring_buffer_iter_empty(iter->buffer_iter[cpu]))
return 0;
} else {
- if (!ring_buffer_empty_cpu(iter->tr->buffer, cpu))
+ if (!ftrace_ring_buffer_empty_cpu(iter->tr->buffer, cpu))
return 0;
}
return 1;
@@ -2036,10 +2036,10 @@ int trace_empty(struct trace_iterator *i
for_each_tracing_cpu(cpu) {
if (iter->buffer_iter[cpu]) {
- if (!ring_buffer_iter_empty(iter->buffer_iter[cpu]))
+ if (!ftrace_ring_buffer_iter_empty(iter->buffer_iter[cpu]))
return 0;
} else {
- if (!ring_buffer_empty_cpu(iter->tr->buffer, cpu))
+ if (!ftrace_ring_buffer_empty_cpu(iter->tr->buffer, cpu))
return 0;
}
}
@@ -2193,7 +2193,7 @@ __tracing_open(struct inode *inode, stru
iter->trace->open(iter);
/* Annotate start of buffers if we had overruns */
- if (ring_buffer_overruns(iter->tr->buffer))
+ if (ftrace_ring_buffer_overruns(iter->tr->buffer))
iter->iter_flags |= TRACE_FILE_ANNOTATE;
/* stop the trace while dumping */
@@ -2202,19 +2202,19 @@ __tracing_open(struct inode *inode, stru
if (iter->cpu_file == TRACE_PIPE_ALL_CPU) {
for_each_tracing_cpu(cpu) {
iter->buffer_iter[cpu] =
- ring_buffer_read_prepare(iter->tr->buffer, cpu);
+ ftrace_ring_buffer_read_prepare(iter->tr->buffer, cpu);
}
- ring_buffer_read_prepare_sync();
+ ftrace_ring_buffer_read_prepare_sync();
for_each_tracing_cpu(cpu) {
- ring_buffer_read_start(iter->buffer_iter[cpu]);
+ ftrace_ring_buffer_read_start(iter->buffer_iter[cpu]);
tracing_iter_reset(iter, cpu);
}
} else {
cpu = iter->cpu_file;
iter->buffer_iter[cpu] =
- ring_buffer_read_prepare(iter->tr->buffer, cpu);
- ring_buffer_read_prepare_sync();
- ring_buffer_read_start(iter->buffer_iter[cpu]);
+ ftrace_ring_buffer_read_prepare(iter->tr->buffer, cpu);
+ ftrace_ring_buffer_read_prepare_sync();
+ ftrace_ring_buffer_read_start(iter->buffer_iter[cpu]);
tracing_iter_reset(iter, cpu);
}
@@ -2234,7 +2234,7 @@ __tracing_open(struct inode *inode, stru
fail_buffer:
for_each_tracing_cpu(cpu) {
if (iter->buffer_iter[cpu])
- ring_buffer_read_finish(iter->buffer_iter[cpu]);
+ ftrace_ring_buffer_read_finish(iter->buffer_iter[cpu]);
}
free_cpumask_var(iter->started);
tracing_start();
@@ -2269,7 +2269,7 @@ static int tracing_release(struct inode
mutex_lock(&trace_types_lock);
for_each_tracing_cpu(cpu) {
if (iter->buffer_iter[cpu])
- ring_buffer_read_finish(iter->buffer_iter[cpu]);
+ ftrace_ring_buffer_read_finish(iter->buffer_iter[cpu]);
}
if (iter->trace && iter->trace->close)
@@ -2782,7 +2782,7 @@ int tracer_init(struct tracer *t, struct
return t->init(tr);
}
-static int tracing_resize_ring_buffer(unsigned long size)
+static int tracing_resize_ftrace_ring_buffer(unsigned long size)
{
int ret;
@@ -2791,17 +2791,17 @@ static int tracing_resize_ring_buffer(un
* we use the size that was given, and we can forget about
* expanding it later.
*/
- ring_buffer_expanded = 1;
+ ftrace_ring_buffer_expanded = 1;
- ret = ring_buffer_resize(global_trace.buffer, size);
+ ret = ftrace_ring_buffer_resize(global_trace.buffer, size);
if (ret < 0)
return ret;
- ret = ring_buffer_resize(max_tr.buffer, size);
+ ret = ftrace_ring_buffer_resize(max_tr.buffer, size);
if (ret < 0) {
int r;
- r = ring_buffer_resize(global_trace.buffer,
+ r = ftrace_ring_buffer_resize(global_trace.buffer,
global_trace.entries);
if (r < 0) {
/*
@@ -2844,8 +2844,8 @@ int tracing_update_buffers(void)
int ret = 0;
mutex_lock(&trace_types_lock);
- if (!ring_buffer_expanded)
- ret = tracing_resize_ring_buffer(trace_buf_size);
+ if (!ftrace_ring_buffer_expanded)
+ ret = tracing_resize_ftrace_ring_buffer(trace_buf_size);
mutex_unlock(&trace_types_lock);
return ret;
@@ -2868,8 +2868,8 @@ static int tracing_set_tracer(const char
mutex_lock(&trace_types_lock);
- if (!ring_buffer_expanded) {
- ret = tracing_resize_ring_buffer(trace_buf_size);
+ if (!ftrace_ring_buffer_expanded) {
+ ret = tracing_resize_ftrace_ring_buffer(trace_buf_size);
if (ret < 0)
goto out;
ret = 0;
@@ -3404,7 +3404,7 @@ tracing_entries_read(struct file *filp,
int r;
mutex_lock(&trace_types_lock);
- if (!ring_buffer_expanded)
+ if (!ftrace_ring_buffer_expanded)
r = sprintf(buf, "%lu (expanded: %lu)\n",
tr->entries >> 10,
trace_buf_size >> 10);
@@ -3455,7 +3455,7 @@ tracing_entries_write(struct file *filp,
val <<= 10;
if (val != global_trace.entries) {
- ret = tracing_resize_ring_buffer(val);
+ ret = tracing_resize_ftrace_ring_buffer(val);
if (ret < 0) {
cnt = ret;
goto out;
@@ -3567,9 +3567,9 @@ static ssize_t tracing_clock_write(struc
mutex_lock(&trace_types_lock);
- ring_buffer_set_clock(global_trace.buffer, trace_clocks[i].func);
+ ftrace_ring_buffer_set_clock(global_trace.buffer, trace_clocks[i].func);
if (max_tr.buffer)
- ring_buffer_set_clock(max_tr.buffer, trace_clocks[i].func);
+ ftrace_ring_buffer_set_clock(max_tr.buffer, trace_clocks[i].func);
mutex_unlock(&trace_types_lock);
@@ -3672,7 +3672,7 @@ tracing_buffers_read(struct file *filp,
return 0;
if (!info->spare)
- info->spare = ring_buffer_alloc_read_page(info->tr->buffer);
+ info->spare = ftrace_ring_buffer_alloc_read_page(info->tr->buffer);
if (!info->spare)
return -ENOMEM;
@@ -3683,7 +3683,7 @@ tracing_buffers_read(struct file *filp,
info->read = 0;
trace_access_lock(info->cpu);
- ret = ring_buffer_read_page(info->tr->buffer,
+ ret = ftrace_ring_buffer_read_page(info->tr->buffer,
&info->spare,
count,
info->cpu, 0);
@@ -3712,14 +3712,14 @@ static int tracing_buffers_release(struc
struct ftrace_buffer_info *info = file->private_data;
if (info->spare)
- ring_buffer_free_read_page(info->tr->buffer, info->spare);
+ ftrace_ring_buffer_free_read_page(info->tr->buffer, info->spare);
kfree(info);
return 0;
}
struct buffer_ref {
- struct ring_buffer *buffer;
+ struct ftrace_ring_buffer *buffer;
void *page;
int ref;
};
@@ -3732,7 +3732,7 @@ static void buffer_pipe_buf_release(stru
if (--ref->ref)
return;
- ring_buffer_free_read_page(ref->buffer, ref->page);
+ ftrace_ring_buffer_free_read_page(ref->buffer, ref->page);
kfree(ref);
buf->private = 0;
}
@@ -3774,7 +3774,7 @@ static void buffer_spd_release(struct sp
if (--ref->ref)
return;
- ring_buffer_free_read_page(ref->buffer, ref->page);
+ ftrace_ring_buffer_free_read_page(ref->buffer, ref->page);
kfree(ref);
spd->partial[i].private = 0;
}
@@ -3817,7 +3817,7 @@ tracing_buffers_splice_read(struct file
}
trace_access_lock(info->cpu);
- entries = ring_buffer_entries_cpu(info->tr->buffer, info->cpu);
+ entries = ftrace_ring_buffer_entries_cpu(info->tr->buffer, info->cpu);
for (i = 0; i < pipe->buffers && len && entries; i++, len -= PAGE_SIZE) {
struct page *page;
@@ -3829,16 +3829,16 @@ tracing_buffers_splice_read(struct file
ref->ref = 1;
ref->buffer = info->tr->buffer;
- ref->page = ring_buffer_alloc_read_page(ref->buffer);
+ ref->page = ftrace_ring_buffer_alloc_read_page(ref->buffer);
if (!ref->page) {
kfree(ref);
break;
}
- r = ring_buffer_read_page(ref->buffer, &ref->page,
+ r = ftrace_ring_buffer_read_page(ref->buffer, &ref->page,
len, info->cpu, 1);
if (r < 0) {
- ring_buffer_free_read_page(ref->buffer,
+ ftrace_ring_buffer_free_read_page(ref->buffer,
ref->page);
kfree(ref);
break;
@@ -3848,7 +3848,7 @@ tracing_buffers_splice_read(struct file
* zero out any left over data, this is going to
* user land.
*/
- size = ring_buffer_page_len(ref->page);
+ size = ftrace_ring_buffer_page_len(ref->page);
if (size < PAGE_SIZE)
memset(ref->page + size, 0, PAGE_SIZE - size);
@@ -3861,7 +3861,7 @@ tracing_buffers_splice_read(struct file
spd.nr_pages++;
*ppos += PAGE_SIZE;
- entries = ring_buffer_entries_cpu(info->tr->buffer, info->cpu);
+ entries = ftrace_ring_buffer_entries_cpu(info->tr->buffer, info->cpu);
}
trace_access_unlock(info->cpu);
@@ -3906,13 +3906,13 @@ tracing_stats_read(struct file *filp, ch
trace_seq_init(s);
- cnt = ring_buffer_entries_cpu(tr->buffer, cpu);
+ cnt = ftrace_ring_buffer_entries_cpu(tr->buffer, cpu);
trace_seq_printf(s, "entries: %ld\n", cnt);
- cnt = ring_buffer_overrun_cpu(tr->buffer, cpu);
+ cnt = ftrace_ring_buffer_overrun_cpu(tr->buffer, cpu);
trace_seq_printf(s, "overrun: %ld\n", cnt);
- cnt = ring_buffer_commit_overrun_cpu(tr->buffer, cpu);
+ cnt = ftrace_ring_buffer_commit_overrun_cpu(tr->buffer, cpu);
trace_seq_printf(s, "commit overrun: %ld\n", cnt);
count = simple_read_from_buffer(ubuf, count, ppos, s->buffer, s->len);
@@ -4554,7 +4554,7 @@ __init static int tracer_alloc_buffers(v
goto out_free_buffer_mask;
/* To save memory, keep the ring buffer size to its minimum */
- if (ring_buffer_expanded)
+ if (ftrace_ring_buffer_expanded)
ring_buf_size = trace_buf_size;
else
ring_buf_size = 1;
@@ -4563,26 +4563,26 @@ __init static int tracer_alloc_buffers(v
cpumask_copy(tracing_cpumask, cpu_all_mask);
/* TODO: make the number of buffers hot pluggable with CPUS */
- global_trace.buffer = ring_buffer_alloc(ring_buf_size,
+ global_trace.buffer = ftrace_ring_buffer_alloc(ring_buf_size,
TRACE_BUFFER_FLAGS);
if (!global_trace.buffer) {
printk(KERN_ERR "tracer: failed to allocate ring buffer!\n");
WARN_ON(1);
goto out_free_cpumask;
}
- global_trace.entries = ring_buffer_size(global_trace.buffer);
+ global_trace.entries = ftrace_ring_buffer_size(global_trace.buffer);
#ifdef CONFIG_TRACER_MAX_TRACE
- max_tr.buffer = ring_buffer_alloc(ring_buf_size,
+ max_tr.buffer = ftrace_ring_buffer_alloc(ring_buf_size,
TRACE_BUFFER_FLAGS);
if (!max_tr.buffer) {
printk(KERN_ERR "tracer: failed to allocate max ring buffer!\n");
WARN_ON(1);
- ring_buffer_free(global_trace.buffer);
+ ftrace_ring_buffer_free(global_trace.buffer);
goto out_free_cpumask;
}
- max_tr.entries = ring_buffer_size(max_tr.buffer);
+ max_tr.entries = ftrace_ring_buffer_size(max_tr.buffer);
WARN_ON(max_tr.entries != global_trace.entries);
#endif
Index: linux.trees.git/kernel/trace/trace.h
===================================================================
--- linux.trees.git.orig/kernel/trace/trace.h 2010-07-09 18:08:14.000000000 -0400
+++ linux.trees.git/kernel/trace/trace.h 2010-07-09 18:08:47.000000000 -0400
@@ -5,7 +5,7 @@
#include <asm/atomic.h>
#include <linux/sched.h>
#include <linux/clocksource.h>
-#include <linux/ring_buffer.h>
+#include <linux/ftrace_ring_buffer.h>
#include <linux/mmiotrace.h>
#include <linux/tracepoint.h>
#include <linux/ftrace.h>
@@ -147,7 +147,7 @@ struct trace_array_cpu {
* They have on/off state as well:
*/
struct trace_array {
- struct ring_buffer *buffer;
+ struct ftrace_ring_buffer *buffer;
unsigned long entries;
int cpu;
cycle_t time_start;
@@ -300,16 +300,16 @@ struct dentry *trace_create_file(const c
struct dentry *tracing_init_dentry(void);
void init_tracer_sysprof_debugfs(struct dentry *d_tracer);
-struct ring_buffer_event;
+struct ftrace_ring_buffer_event;
-struct ring_buffer_event *
-trace_buffer_lock_reserve(struct ring_buffer *buffer,
+struct ftrace_ring_buffer_event *
+trace_buffer_lock_reserve(struct ftrace_ring_buffer *buffer,
int type,
unsigned long len,
unsigned long flags,
int pc);
-void trace_buffer_unlock_commit(struct ring_buffer *buffer,
- struct ring_buffer_event *event,
+void trace_buffer_unlock_commit(struct ftrace_ring_buffer *buffer,
+ struct ftrace_ring_buffer_event *event,
unsigned long flags, int pc);
struct trace_entry *tracing_get_trace_entry(struct trace_array *tr,
@@ -376,21 +376,21 @@ void update_max_tr_single(struct trace_a
#endif /* CONFIG_TRACER_MAX_TRACE */
#ifdef CONFIG_STACKTRACE
-void ftrace_trace_stack(struct ring_buffer *buffer, unsigned long flags,
+void ftrace_trace_stack(struct ftrace_ring_buffer *buffer, unsigned long flags,
int skip, int pc);
-void ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags,
+void ftrace_trace_userstack(struct ftrace_ring_buffer *buffer, unsigned long flags,
int pc);
void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
int pc);
#else
-static inline void ftrace_trace_stack(struct ring_buffer *buffer,
+static inline void ftrace_trace_stack(struct ftrace_ring_buffer *buffer,
unsigned long flags, int skip, int pc)
{
}
-static inline void ftrace_trace_userstack(struct ring_buffer *buffer,
+static inline void ftrace_trace_userstack(struct ftrace_ring_buffer *buffer,
unsigned long flags, int pc)
{
}
@@ -411,7 +411,7 @@ extern unsigned long ftrace_update_tot_c
extern int DYN_FTRACE_TEST_NAME(void);
#endif
-extern int ring_buffer_expanded;
+extern int ftrace_ring_buffer_expanded;
extern bool tracing_selftest_disabled;
DECLARE_PER_CPU(int, ftrace_cpu_disabled);
@@ -717,12 +717,12 @@ trace_get_fields(struct ftrace_event_cal
static inline int
filter_check_discard(struct ftrace_event_call *call, void *rec,
- struct ring_buffer *buffer,
- struct ring_buffer_event *event)
+ struct ftrace_ring_buffer *buffer,
+ struct ftrace_ring_buffer_event *event)
{
if (unlikely(call->flags & TRACE_EVENT_FL_FILTERED) &&
!filter_match_preds(call->filter, rec)) {
- ring_buffer_discard_commit(buffer, event);
+ ftrace_ring_buffer_discard_commit(buffer, event);
return 1;
}
Index: linux.trees.git/kernel/trace/trace_branch.c
===================================================================
--- linux.trees.git.orig/kernel/trace/trace_branch.c 2010-07-09 18:08:14.000000000 -0400
+++ linux.trees.git/kernel/trace/trace_branch.c 2010-07-09 18:08:47.000000000 -0400
@@ -32,9 +32,9 @@ probe_likely_condition(struct ftrace_bra
{
struct ftrace_event_call *call = &event_branch;
struct trace_array *tr = branch_tracer;
- struct ring_buffer_event *event;
+ struct ftrace_ring_buffer_event *event;
struct trace_branch *entry;
- struct ring_buffer *buffer;
+ struct ftrace_ring_buffer *buffer;
unsigned long flags;
int cpu, pc;
const char *p;
@@ -61,7 +61,7 @@ probe_likely_condition(struct ftrace_bra
if (!event)
goto out;
- entry = ring_buffer_event_data(event);
+ entry = ftrace_ring_buffer_event_data(event);
/* Strip off the path, only save the file */
p = f->file + strlen(f->file);
@@ -77,7 +77,7 @@ probe_likely_condition(struct ftrace_bra
entry->correct = val == expect;
if (!filter_check_discard(call, entry, buffer, event))
- ring_buffer_unlock_commit(buffer, event);
+ ftrace_ring_buffer_unlock_commit(buffer, event);
out:
atomic_dec(&tr->data[cpu]->disabled);
Index: linux.trees.git/kernel/trace/trace_events.c
===================================================================
--- linux.trees.git.orig/kernel/trace/trace_events.c 2010-07-09 18:08:14.000000000 -0400
+++ linux.trees.git/kernel/trace/trace_events.c 2010-07-09 18:08:47.000000000 -0400
@@ -1277,7 +1277,7 @@ static char bootup_event_buf[COMMAND_LIN
static __init int setup_trace_event(char *str)
{
strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE);
- ring_buffer_expanded = 1;
+ ftrace_ring_buffer_expanded = 1;
tracing_selftest_disabled = 1;
return 1;
@@ -1318,11 +1318,11 @@ static __init int event_trace_init(void)
/* ring buffer internal formats */
trace_create_file("header_page", 0444, d_events,
- ring_buffer_print_page_header,
+ ftrace_ring_buffer_print_page_header,
&ftrace_show_header_fops);
trace_create_file("header_event", 0444, d_events,
- ring_buffer_print_entry_header,
+ ftrace_ring_buffer_print_entry_header,
&ftrace_show_header_fops);
trace_create_file("enable", 0644, d_events,
@@ -1517,8 +1517,8 @@ static DEFINE_PER_CPU(atomic_t, ftrace_t
static void
function_test_events_call(unsigned long ip, unsigned long parent_ip)
{
- struct ring_buffer_event *event;
- struct ring_buffer *buffer;
+ struct ftrace_ring_buffer_event *event;
+ struct ftrace_ring_buffer *buffer;
struct ftrace_entry *entry;
unsigned long flags;
long disabled;
@@ -1540,7 +1540,7 @@ function_test_events_call(unsigned long
flags, pc);
if (!event)
goto out;
- entry = ring_buffer_event_data(event);
+ entry = ftrace_ring_buffer_event_data(event);
entry->ip = ip;
entry->parent_ip = parent_ip;
Index: linux.trees.git/kernel/trace/trace_functions_graph.c
===================================================================
--- linux.trees.git.orig/kernel/trace/trace_functions_graph.c 2010-07-09 18:08:14.000000000 -0400
+++ linux.trees.git/kernel/trace/trace_functions_graph.c 2010-07-09 18:08:47.000000000 -0400
@@ -185,8 +185,8 @@ int __trace_graph_entry(struct trace_arr
int pc)
{
struct ftrace_event_call *call = &event_funcgraph_entry;
- struct ring_buffer_event *event;
- struct ring_buffer *buffer = tr->buffer;
+ struct ftrace_ring_buffer_event *event;
+ struct ftrace_ring_buffer *buffer = tr->buffer;
struct ftrace_graph_ent_entry *entry;
if (unlikely(__this_cpu_read(ftrace_cpu_disabled)))
@@ -196,10 +196,10 @@ int __trace_graph_entry(struct trace_arr
sizeof(*entry), flags, pc);
if (!event)
return 0;
- entry = ring_buffer_event_data(event);
+ entry = ftrace_ring_buffer_event_data(event);
entry->graph_ent = *trace;
if (!filter_current_check_discard(buffer, call, entry, event))
- ring_buffer_unlock_commit(buffer, event);
+ ftrace_ring_buffer_unlock_commit(buffer, event);
return 1;
}
@@ -252,8 +252,8 @@ void __trace_graph_return(struct trace_a
int pc)
{
struct ftrace_event_call *call = &event_funcgraph_exit;
- struct ring_buffer_event *event;
- struct ring_buffer *buffer = tr->buffer;
+ struct ftrace_ring_buffer_event *event;
+ struct ftrace_ring_buffer *buffer = tr->buffer;
struct ftrace_graph_ret_entry *entry;
if (unlikely(__this_cpu_read(ftrace_cpu_disabled)))
@@ -263,10 +263,10 @@ void __trace_graph_return(struct trace_a
sizeof(*entry), flags, pc);
if (!event)
return;
- entry = ring_buffer_event_data(event);
+ entry = ftrace_ring_buffer_event_data(event);
entry->ret = *trace;
if (!filter_current_check_discard(buffer, call, entry, event))
- ring_buffer_unlock_commit(buffer, event);
+ ftrace_ring_buffer_unlock_commit(buffer, event);
}
void trace_graph_return(struct ftrace_graph_ret *trace)
@@ -467,8 +467,8 @@ get_return_for_leaf(struct trace_iterato
struct ftrace_graph_ent_entry *curr)
{
struct fgraph_data *data = iter->private;
- struct ring_buffer_iter *ring_iter = NULL;
- struct ring_buffer_event *event;
+ struct ftrace_ring_buffer_iter *ring_iter = NULL;
+ struct ftrace_ring_buffer_event *event;
struct ftrace_graph_ret_entry *next;
/*
@@ -484,22 +484,22 @@ get_return_for_leaf(struct trace_iterato
/* First peek to compare current entry and the next one */
if (ring_iter)
- event = ring_buffer_iter_peek(ring_iter, NULL);
+ event = ftrace_ring_buffer_iter_peek(ring_iter, NULL);
else {
/*
* We need to consume the current entry to see
* the next one.
*/
- ring_buffer_consume(iter->tr->buffer, iter->cpu,
+ ftrace_ring_buffer_consume(iter->tr->buffer, iter->cpu,
NULL, NULL);
- event = ring_buffer_peek(iter->tr->buffer, iter->cpu,
+ event = ftrace_ring_buffer_peek(iter->tr->buffer, iter->cpu,
NULL, NULL);
}
if (!event)
return NULL;
- next = ring_buffer_event_data(event);
+ next = ftrace_ring_buffer_event_data(event);
if (data) {
/*
@@ -520,7 +520,7 @@ get_return_for_leaf(struct trace_iterato
/* this is a leaf, now advance the iterator */
if (ring_iter)
- ring_buffer_read(ring_iter, NULL);
+ ftrace_ring_buffer_read(ring_iter, NULL);
return next;
}
Index: linux.trees.git/kernel/trace/trace_kprobe.c
===================================================================
--- linux.trees.git.orig/kernel/trace/trace_kprobe.c 2010-07-09 18:08:14.000000000 -0400
+++ linux.trees.git/kernel/trace/trace_kprobe.c 2010-07-09 18:08:47.000000000 -0400
@@ -1264,8 +1264,8 @@ static __kprobes void kprobe_trace_func(
{
struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
struct kprobe_trace_entry_head *entry;
- struct ring_buffer_event *event;
- struct ring_buffer *buffer;
+ struct ftrace_ring_buffer_event *event;
+ struct ftrace_ring_buffer *buffer;
int size, dsize, pc;
unsigned long irq_flags;
struct ftrace_event_call *call = &tp->call;
@@ -1283,7 +1283,7 @@ static __kprobes void kprobe_trace_func(
if (!event)
return;
- entry = ring_buffer_event_data(event);
+ entry = ftrace_ring_buffer_event_data(event);
entry->ip = (unsigned long)kp->addr;
store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
@@ -1297,8 +1297,8 @@ static __kprobes void kretprobe_trace_fu
{
struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
struct kretprobe_trace_entry_head *entry;
- struct ring_buffer_event *event;
- struct ring_buffer *buffer;
+ struct ftrace_ring_buffer_event *event;
+ struct ftrace_ring_buffer *buffer;
int size, pc, dsize;
unsigned long irq_flags;
struct ftrace_event_call *call = &tp->call;
@@ -1314,7 +1314,7 @@ static __kprobes void kretprobe_trace_fu
if (!event)
return;
- entry = ring_buffer_event_data(event);
+ entry = ftrace_ring_buffer_event_data(event);
entry->func = (unsigned long)tp->rp.kp.addr;
entry->ret_ip = (unsigned long)ri->ret_addr;
store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
Index: linux.trees.git/kernel/trace/trace_ksym.c
===================================================================
--- linux.trees.git.orig/kernel/trace/trace_ksym.c 2010-07-09 18:08:14.000000000 -0400
+++ linux.trees.git/kernel/trace/trace_ksym.c 2010-07-09 18:08:47.000000000 -0400
@@ -77,9 +77,9 @@ void ksym_hbp_handler(struct perf_event
struct perf_sample_data *data,
struct pt_regs *regs)
{
- struct ring_buffer_event *event;
+ struct ftrace_ring_buffer_event *event;
struct ksym_trace_entry *entry;
- struct ring_buffer *buffer;
+ struct ftrace_ring_buffer *buffer;
int pc;
if (!ksym_tracing_enabled)
@@ -94,7 +94,7 @@ void ksym_hbp_handler(struct perf_event
if (!event)
return;
- entry = ring_buffer_event_data(event);
+ entry = ftrace_ring_buffer_event_data(event);
entry->ip = instruction_pointer(regs);
entry->type = hw_breakpoint_type(hbp);
entry->addr = hw_breakpoint_addr(hbp);
Index: linux.trees.git/kernel/trace/trace_mmiotrace.c
===================================================================
--- linux.trees.git.orig/kernel/trace/trace_mmiotrace.c 2010-07-09 18:08:14.000000000 -0400
+++ linux.trees.git/kernel/trace/trace_mmiotrace.c 2010-07-09 18:08:47.000000000 -0400
@@ -128,7 +128,7 @@ static void mmio_close(struct trace_iter
static unsigned long count_overruns(struct trace_iterator *iter)
{
unsigned long cnt = atomic_xchg(&dropped_count, 0);
- unsigned long over = ring_buffer_overruns(iter->tr->buffer);
+ unsigned long over = ftrace_ring_buffer_overruns(iter->tr->buffer);
if (over > prev_overruns)
cnt += over - prev_overruns;
@@ -309,8 +309,8 @@ static void __trace_mmiotrace_rw(struct
struct mmiotrace_rw *rw)
{
struct ftrace_event_call *call = &event_mmiotrace_rw;
- struct ring_buffer *buffer = tr->buffer;
- struct ring_buffer_event *event;
+ struct ftrace_ring_buffer *buffer = tr->buffer;
+ struct ftrace_ring_buffer_event *event;
struct trace_mmiotrace_rw *entry;
int pc = preempt_count();
@@ -320,7 +320,7 @@ static void __trace_mmiotrace_rw(struct
atomic_inc(&dropped_count);
return;
}
- entry = ring_buffer_event_data(event);
+ entry = ftrace_ring_buffer_event_data(event);
entry->rw = *rw;
if (!filter_check_discard(call, entry, buffer, event))
@@ -339,8 +339,8 @@ static void __trace_mmiotrace_map(struct
struct mmiotrace_map *map)
{
struct ftrace_event_call *call = &event_mmiotrace_map;
- struct ring_buffer *buffer = tr->buffer;
- struct ring_buffer_event *event;
+ struct ftrace_ring_buffer *buffer = tr->buffer;
+ struct ftrace_ring_buffer_event *event;
struct trace_mmiotrace_map *entry;
int pc = preempt_count();
@@ -350,7 +350,7 @@ static void __trace_mmiotrace_map(struct
atomic_inc(&dropped_count);
return;
}
- entry = ring_buffer_event_data(event);
+ entry = ftrace_ring_buffer_event_data(event);
entry->map = *map;
if (!filter_check_discard(call, entry, buffer, event))
Index: linux.trees.git/kernel/trace/trace_sched_switch.c
===================================================================
--- linux.trees.git.orig/kernel/trace/trace_sched_switch.c 2010-07-09 18:08:14.000000000 -0400
+++ linux.trees.git/kernel/trace/trace_sched_switch.c 2010-07-09 18:08:47.000000000 -0400
@@ -28,15 +28,15 @@ tracing_sched_switch_trace(struct trace_
unsigned long flags, int pc)
{
struct ftrace_event_call *call = &event_context_switch;
- struct ring_buffer *buffer = tr->buffer;
- struct ring_buffer_event *event;
+ struct ftrace_ring_buffer *buffer = tr->buffer;
+ struct ftrace_ring_buffer_event *event;
struct ctx_switch_entry *entry;
event = trace_buffer_lock_reserve(buffer, TRACE_CTX,
sizeof(*entry), flags, pc);
if (!event)
return;
- entry = ring_buffer_event_data(event);
+ entry = ftrace_ring_buffer_event_data(event);
entry->prev_pid = prev->pid;
entry->prev_prio = prev->prio;
entry->prev_state = prev->state;
@@ -84,15 +84,15 @@ tracing_sched_wakeup_trace(struct trace_
unsigned long flags, int pc)
{
struct ftrace_event_call *call = &event_wakeup;
- struct ring_buffer_event *event;
+ struct ftrace_ring_buffer_event *event;
struct ctx_switch_entry *entry;
- struct ring_buffer *buffer = tr->buffer;
+ struct ftrace_ring_buffer *buffer = tr->buffer;
event = trace_buffer_lock_reserve(buffer, TRACE_WAKE,
sizeof(*entry), flags, pc);
if (!event)
return;
- entry = ring_buffer_event_data(event);
+ entry = ftrace_ring_buffer_event_data(event);
entry->prev_pid = curr->pid;
entry->prev_prio = curr->prio;
entry->prev_state = curr->state;
@@ -102,7 +102,7 @@ tracing_sched_wakeup_trace(struct trace_
entry->next_cpu = task_cpu(wakee);
if (!filter_check_discard(call, entry, buffer, event))
- ring_buffer_unlock_commit(buffer, event);
+ ftrace_ring_buffer_unlock_commit(buffer, event);
ftrace_trace_stack(tr->buffer, flags, 6, pc);
ftrace_trace_userstack(tr->buffer, flags, pc);
}
Index: linux.trees.git/kernel/trace/trace_selftest.c
===================================================================
--- linux.trees.git.orig/kernel/trace/trace_selftest.c 2010-07-09 18:08:14.000000000 -0400
+++ linux.trees.git/kernel/trace/trace_selftest.c 2010-07-09 18:08:47.000000000 -0400
@@ -25,12 +25,12 @@ static inline int trace_valid_entry(stru
static int trace_test_buffer_cpu(struct trace_array *tr, int cpu)
{
- struct ring_buffer_event *event;
+ struct ftrace_ring_buffer_event *event;
struct trace_entry *entry;
unsigned int loops = 0;
- while ((event = ring_buffer_consume(tr->buffer, cpu, NULL, NULL))) {
- entry = ring_buffer_event_data(event);
+ while ((event = ftrace_ring_buffer_consume(tr->buffer, cpu, NULL, NULL))) {
+ entry = ftrace_ring_buffer_event_data(event);
/*
* The ring buffer is a size of trace_buf_size, if
@@ -69,7 +69,7 @@ static int trace_test_buffer(struct trac
local_irq_save(flags);
arch_spin_lock(&ftrace_max_lock);
- cnt = ring_buffer_entries(tr->buffer);
+ cnt = ftrace_ring_buffer_entries(tr->buffer);
/*
* The trace_test_buffer_cpu runs a while loop to consume all data.
Index: linux.trees.git/kernel/trace/trace_syscalls.c
===================================================================
--- linux.trees.git.orig/kernel/trace/trace_syscalls.c 2010-07-09 18:08:14.000000000 -0400
+++ linux.trees.git/kernel/trace/trace_syscalls.c 2010-07-09 18:08:47.000000000 -0400
@@ -298,8 +298,8 @@ void ftrace_syscall_enter(void *ignore,
{
struct syscall_trace_enter *entry;
struct syscall_metadata *sys_data;
- struct ring_buffer_event *event;
- struct ring_buffer *buffer;
+ struct ftrace_ring_buffer_event *event;
+ struct ftrace_ring_buffer *buffer;
int size;
int syscall_nr;
@@ -320,7 +320,7 @@ void ftrace_syscall_enter(void *ignore,
if (!event)
return;
- entry = ring_buffer_event_data(event);
+ entry = ftrace_ring_buffer_event_data(event);
entry->nr = syscall_nr;
syscall_get_arguments(current, regs, 0, sys_data->nb_args, entry->args);
@@ -333,8 +333,8 @@ void ftrace_syscall_exit(void *ignore, s
{
struct syscall_trace_exit *entry;
struct syscall_metadata *sys_data;
- struct ring_buffer_event *event;
- struct ring_buffer *buffer;
+ struct ftrace_ring_buffer_event *event;
+ struct ftrace_ring_buffer *buffer;
int syscall_nr;
syscall_nr = syscall_get_nr(current, regs);
@@ -352,7 +352,7 @@ void ftrace_syscall_exit(void *ignore, s
if (!event)
return;
- entry = ring_buffer_event_data(event);
+ entry = ftrace_ring_buffer_event_data(event);
entry->nr = syscall_nr;
entry->ret = syscall_get_return_value(current, regs);
Index: linux.trees.git/drivers/oprofile/cpu_buffer.c
===================================================================
--- linux.trees.git.orig/drivers/oprofile/cpu_buffer.c 2010-07-09 18:08:14.000000000 -0400
+++ linux.trees.git/drivers/oprofile/cpu_buffer.c 2010-07-09 18:08:47.000000000 -0400
@@ -30,7 +30,7 @@
#define OP_BUFFER_FLAGS 0
-static struct ring_buffer *op_ring_buffer;
+static struct ftrace_ring_buffer *op_ftrace_ring_buffer;
DEFINE_PER_CPU(struct oprofile_cpu_buffer, op_cpu_buffer);
static void wq_sync_buffer(struct work_struct *work);
@@ -52,9 +52,9 @@ void oprofile_cpu_buffer_inc_smpl_lost(v
void free_cpu_buffers(void)
{
- if (op_ring_buffer)
- ring_buffer_free(op_ring_buffer);
- op_ring_buffer = NULL;
+ if (op_ftrace_ring_buffer)
+ ftrace_ring_buffer_free(op_ftrace_ring_buffer);
+ op_ftrace_ring_buffer = NULL;
}
#define RB_EVENT_HDR_SIZE 4
@@ -67,8 +67,8 @@ int alloc_cpu_buffers(void)
unsigned long byte_size = buffer_size * (sizeof(struct op_sample) +
RB_EVENT_HDR_SIZE);
- op_ring_buffer = ring_buffer_alloc(byte_size, OP_BUFFER_FLAGS);
- if (!op_ring_buffer)
+ op_ftrace_ring_buffer = ftrace_ring_buffer_alloc(byte_size, OP_BUFFER_FLAGS);
+ if (!op_ftrace_ring_buffer)
goto fail;
for_each_possible_cpu(i) {
@@ -139,12 +139,12 @@ void end_cpu_work(void)
struct op_sample
*op_cpu_buffer_write_reserve(struct op_entry *entry, unsigned long size)
{
- entry->event = ring_buffer_lock_reserve
- (op_ring_buffer, sizeof(struct op_sample) +
+ entry->event = ftrace_ring_buffer_lock_reserve
+ (op_ftrace_ring_buffer, sizeof(struct op_sample) +
size * sizeof(entry->sample->data[0]));
if (!entry->event)
return NULL;
- entry->sample = ring_buffer_event_data(entry->event);
+ entry->sample = ftrace_ring_buffer_event_data(entry->event);
entry->size = size;
entry->data = entry->sample->data;
@@ -153,19 +153,19 @@ struct op_sample
int op_cpu_buffer_write_commit(struct op_entry *entry)
{
- return ring_buffer_unlock_commit(op_ring_buffer, entry->event);
+ return ftrace_ring_buffer_unlock_commit(op_ftrace_ring_buffer, entry->event);
}
struct op_sample *op_cpu_buffer_read_entry(struct op_entry *entry, int cpu)
{
- struct ring_buffer_event *e;
- e = ring_buffer_consume(op_ring_buffer, cpu, NULL, NULL);
+ struct ftrace_ring_buffer_event *e;
+ e = ftrace_ring_buffer_consume(op_ftrace_ring_buffer, cpu, NULL, NULL);
if (!e)
return NULL;
entry->event = e;
- entry->sample = ring_buffer_event_data(e);
- entry->size = (ring_buffer_event_length(e) - sizeof(struct op_sample))
+ entry->sample = ftrace_ring_buffer_event_data(e);
+ entry->size = (ftrace_ring_buffer_event_length(e) - sizeof(struct op_sample))
/ sizeof(entry->sample->data[0]);
entry->data = entry->sample->data;
return entry->sample;
@@ -173,7 +173,7 @@ struct op_sample *op_cpu_buffer_read_ent
unsigned long op_cpu_buffer_entries(int cpu)
{
- return ring_buffer_entries_cpu(op_ring_buffer, cpu);
+ return ftrace_ring_buffer_entries_cpu(op_ftrace_ring_buffer, cpu);
}
static int
Index: linux.trees.git/drivers/oprofile/cpu_buffer.h
===================================================================
--- linux.trees.git.orig/drivers/oprofile/cpu_buffer.h 2010-07-09 18:08:14.000000000 -0400
+++ linux.trees.git/drivers/oprofile/cpu_buffer.h 2010-07-09 18:08:47.000000000 -0400
@@ -16,7 +16,7 @@
#include <linux/workqueue.h>
#include <linux/cache.h>
#include <linux/sched.h>
-#include <linux/ring_buffer.h>
+#include <linux/ftrace_ring_buffer.h>
struct task_struct;
Index: linux.trees.git/include/linux/kernel.h
===================================================================
--- linux.trees.git.orig/include/linux/kernel.h 2010-07-09 18:08:28.000000000 -0400
+++ linux.trees.git/include/linux/kernel.h 2010-07-09 18:08:47.000000000 -0400
@@ -485,7 +485,7 @@ extern int hex_to_bin(char ch);
*
* Most likely, you want to use tracing_on/tracing_off.
*/
-#ifdef CONFIG_RING_BUFFER
+#ifdef CONFIG_FTRACE_RING_BUFFER
void tracing_on(void);
void tracing_off(void);
/* trace_off_permanent stops recording with no way to bring it back */
Index: linux.trees.git/kernel/trace/trace_functions.c
===================================================================
--- linux.trees.git.orig/kernel/trace/trace_functions.c 2010-07-09 18:08:14.000000000 -0400
+++ linux.trees.git/kernel/trace/trace_functions.c 2010-07-09 18:08:47.000000000 -0400
@@ -9,7 +9,7 @@
* Copyright (C) 2004-2006 Ingo Molnar
* Copyright (C) 2004 William Lee Irwin III
*/
-#include <linux/ring_buffer.h>
+#include <linux/ftrace_ring_buffer.h>
#include <linux/debugfs.h>
#include <linux/uaccess.h>
#include <linux/ftrace.h>
next prev parent reply other threads:[~2010-07-09 23:06 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-09 22:57 [patch 00/20] Generic Ring Buffer Library Mathieu Desnoyers
2010-07-09 22:57 ` [patch 01/20] Create generic alignment API (v8) Mathieu Desnoyers
2010-08-06 11:41 ` Alexander Shishkin
2010-08-06 14:48 ` Mathieu Desnoyers
2010-07-09 22:57 ` [patch 02/20] notifier atomic call chain notrace Mathieu Desnoyers
2010-07-09 22:57 ` [patch 03/20] idle notifier standardization Mathieu Desnoyers
2010-07-09 22:57 ` [patch 04/20] idle notifier standardization x86_32 Mathieu Desnoyers
2010-07-09 22:57 ` [patch 05/20] Poll : add poll_wait_set_exclusive Mathieu Desnoyers
2010-07-09 22:57 ` [patch 06/20] prio_heap: heap_remove(), heap_maximum(), heap_replace() and heap_cherrypick() Mathieu Desnoyers
2010-07-09 22:57 ` [patch 07/20] kthread_kill_stop() Mathieu Desnoyers
2010-07-09 22:57 ` [patch 08/20] inline memcpy Mathieu Desnoyers
2010-07-09 22:57 ` [patch 09/20] x86 " Mathieu Desnoyers
2010-07-09 22:57 ` [patch 10/20] Trace clock - build standalone Mathieu Desnoyers
2010-07-09 22:57 ` Mathieu Desnoyers [this message]
2010-07-09 22:57 ` [patch 12/20] ring buffer backend Mathieu Desnoyers
2010-07-09 22:57 ` [patch 13/20] ring buffer frontend Mathieu Desnoyers
2010-07-09 22:57 ` [patch 14/20] Ring buffer library - documentation Mathieu Desnoyers
2010-07-09 22:57 ` [patch 15/20] Ring buffer library - VFS operations Mathieu Desnoyers
2010-07-09 22:57 ` [patch 16/20] Ring buffer library - client sample Mathieu Desnoyers
2010-07-09 22:57 ` [patch 17/20] Ring buffer benchmark library Mathieu Desnoyers
2010-07-09 22:57 ` [patch 18/20] Ring Buffer Record Iterator Mathieu Desnoyers
2010-07-09 22:57 ` [patch 19/20] Ring Buffer: Basic API Mathieu Desnoyers
2010-07-09 22:57 ` [patch 20/20] Ring buffer: benchmark simple API Mathieu Desnoyers
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