[RFC PATCH] perf: Split up buffer handling from core code

Frederic Weisbecker
2011-05-19T01:06:34Z

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Keeping perf_output_copy() inlined is responsible
of some ugliness there.

A solution could be to have an internal only
perf_output_copy_inline() version in internal.h
and a wrapper in buffer.c that exports it.

Or we can completely uninline it.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Stephane Eranian <eranian@google.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
include/linux/perf_event.h | 47 +++++-
kernel/events/Makefile | 2 +-
kernel/events/buffer.c | 394 +++++++++++++++++++++++++++++++++++++++
kernel/events/core.c | 442 +-------------------------------------------
kernel/events/internal.h | 28 +++
5 files changed, 476 insertions(+), 437 deletions(-)
create mode 100644 kernel/events/buffer.c
create mode 100644 kernel/events/internal.h

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 3412684..02952d4 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -1142,12 +1142,55 @@ extern void perf_bp_event(struct perf_event *event, void *data);
# define perf_instruction_pointer(regs) instruction_pointer(regs)
#endif

+#ifdef CONFIG_PERF_USE_VMALLOC
+/*
+ * Back perf_mmap() with vmalloc memory.
+ *
+ * Required for architectures that have d-cache aliasing issues.
+ */
+
+static inline int perf_output_page_order(struct perf_buffer *buffer)
+{
+ return buffer->page_order;
+}
+
+#else
+
+static inline int perf_output_page_order(struct perf_buffer *buffer)
+{
+ return 0;
+}
+#endif
+
extern int perf_output_begin(struct perf_output_handle *handle,
struct perf_event *event, unsigned int size,
int nmi, int sample);
extern void perf_output_end(struct perf_output_handle *handle);
-extern void perf_output_copy(struct perf_output_handle *handle,
- const void *buf, unsigned int len);
+
+static inline void
+perf_output_copy(struct perf_output_handle *handle,
+ const void *buf, unsigned int len)
+{
+ do {
+ unsigned long size = min_t(unsigned long, handle->size, len);
+
+ memcpy(handle->addr, buf, size);
+
+ len -= size;
+ handle->addr += size;
+ buf += size;
+ handle->size -= size;
+ if (!handle->size) {
+ struct perf_buffer *buffer = handle->buffer;
+
+ handle->page++;
+ handle->page &= buffer->nr_pages - 1;
+ handle->addr = buffer->data_pages[handle->page];
+ handle->size = PAGE_SIZE << perf_output_page_order(buffer);
+ }
+ } while (len);
+}
+
extern int perf_swevent_get_recursion_context(void);
extern void perf_swevent_put_recursion_context(int rctx);
extern void perf_event_enable(struct perf_event *event);
diff --git a/kernel/events/Makefile b/kernel/events/Makefile
index 1ce23d3..b66b057 100644
--- a/kernel/events/Makefile
+++ b/kernel/events/Makefile
@@ -2,5 +2,5 @@ ifdef CONFIG_FUNCTION_TRACER
CFLAGS_REMOVE_core.o = -pg
endif

-obj-y := core.o
+obj-y := core.o buffer.o
obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o
diff --git a/kernel/events/buffer.c b/kernel/events/buffer.c
new file mode 100644
index 0000000..03493d4
--- /dev/null
+++ b/kernel/events/buffer.c
@@ -0,0 +1,394 @@
+/*
+ * Performance events buffer code:
+ *
+ * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
+ * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
+ * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
+ * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
+ *
+ * For licensing details see kernel-base/COPYING
+ */
+
+#include <linux/slab.h>
+#include <linux/perf_event.h>
+#include "internal.h"
+
+
+static bool perf_output_space(struct perf_buffer *buffer, unsigned long tail,
+ unsigned long offset, unsigned long head)
+{
+ unsigned long mask;
+
+ if (!buffer->writable)
+ return true;
+
+ mask = perf_data_size(buffer) - 1;
+
+ offset = (offset - tail) & mask;
+ head = (head - tail) & mask;
+
+ if ((int)(head - offset) < 0)
+ return false;
+
+ return true;
+}
+
+static void perf_output_wakeup(struct perf_output_handle *handle)
+{
+ atomic_set(&handle->buffer->poll, POLL_IN);
+
+ if (handle->nmi) {
+ handle->event->pending_wakeup = 1;
+ irq_work_queue(&handle->event->pending);
+ } else
+ perf_event_wakeup(handle->event);
+}
+
+/*
+ * We need to ensure a later event_id doesn't publish a head when a former
+ * event isn't done writing. However since we need to deal with NMIs we
+ * cannot fully serialize things.
+ *
+ * We only publish the head (and generate a wakeup) when the outer-most
+ * event completes.
+ */
+static void perf_output_get_handle(struct perf_output_handle *handle)
+{
+ struct perf_buffer *buffer = handle->buffer;
+
+ preempt_disable();
+ local_inc(&buffer->nest);
+ handle->wakeup = local_read(&buffer->wakeup);
+}
+
+static void perf_output_put_handle(struct perf_output_handle *handle)
+{
+ struct perf_buffer *buffer = handle->buffer;
+ unsigned long head;
+
+again:
+ head = local_read(&buffer->head);
+
+ /*
+ * IRQ/NMI can happen here, which means we can miss a head update.
+ */
+
+ if (!local_dec_and_test(&buffer->nest))
+ goto out;
+
+ /*
+ * Publish the known good head. Rely on the full barrier implied
+ * by atomic_dec_and_test() order the buffer->head read and this
+ * write.
+ */
+ buffer->user_page->data_head = head;
+
+ /*
+ * Now check if we missed an update, rely on the (compiler)
+ * barrier in atomic_dec_and_test() to re-read buffer->head.
+ */
+ if (unlikely(head != local_read(&buffer->head))) {
+ local_inc(&buffer->nest);
+ goto again;
+ }
+
+ if (handle->wakeup != local_read(&buffer->wakeup))
+ perf_output_wakeup(handle);
+
+out:
+ preempt_enable();
+}
+
+int perf_output_begin(struct perf_output_handle *handle,
+ struct perf_event *event, unsigned int size,
+ int nmi, int sample)
+{
+ struct perf_buffer *buffer;
+ unsigned long tail, offset, head;
+ int have_lost;
+ struct perf_sample_data sample_data;
+ struct {
+ struct perf_event_header header;
+ u64 id;
+ u64 lost;
+ } lost_event;
+
+ rcu_read_lock();
+ /*
+ * For inherited events we send all the output towards the parent.
+ */
+ if (event->parent)
+ event = event->parent;
+
+ buffer = rcu_dereference(event->buffer);
+ if (!buffer)
+ goto out;
+
+ handle->buffer = buffer;
+ handle->event = event;
+ handle->nmi = nmi;
+ handle->sample = sample;
+
+ if (!buffer->nr_pages)
+ goto out;
+
+ have_lost = local_read(&buffer->lost);
+ if (have_lost) {
+ lost_event.header.size = sizeof(lost_event);
+ perf_event_header__init_id(&lost_event.header, &sample_data,
+ event);
+ size += lost_event.header.size;
+ }
+
+ perf_output_get_handle(handle);
+
+ do {
+ /*
+ * Userspace could choose to issue a mb() before updating the
+ * tail pointer. So that all reads will be completed before the
+ * write is issued.
+ */
+ tail = ACCESS_ONCE(buffer->user_page->data_tail);
+ smp_rmb();
+ offset = head = local_read(&buffer->head);
+ head += size;
+ if (unlikely(!perf_output_space(buffer, tail, offset, head)))
+ goto fail;
+ } while (local_cmpxchg(&buffer->head, offset, head) != offset);
+
+ if (head - local_read(&buffer->wakeup) > buffer->watermark)
+ local_add(buffer->watermark, &buffer->wakeup);
+
+ handle->page = offset >> (PAGE_SHIFT + perf_output_page_order(buffer));
+ handle->page &= buffer->nr_pages - 1;
+ handle->size = offset & ((PAGE_SIZE << perf_output_page_order(buffer)) - 1);
+ handle->addr = buffer->data_pages[handle->page];
+ handle->addr += handle->size;
+ handle->size = (PAGE_SIZE << perf_output_page_order(buffer)) - handle->size;
+
+ if (have_lost) {
+ lost_event.header.type = PERF_RECORD_LOST;
+ lost_event.header.misc = 0;
+ lost_event.id = event->id;
+ lost_event.lost = local_xchg(&buffer->lost, 0);
+
+ perf_output_put(handle, lost_event);
+ perf_event__output_id_sample(event, handle, &sample_data);
+ }
+
+ return 0;
+
+fail:
+ local_inc(&buffer->lost);
+ perf_output_put_handle(handle);
+out:
+ rcu_read_unlock();
+
+ return -ENOSPC;
+}
+
+void perf_output_end(struct perf_output_handle *handle)
+{
+ struct perf_event *event = handle->event;
+ struct perf_buffer *buffer = handle->buffer;
+
+ int wakeup_events = event->attr.wakeup_events;
+
+ if (handle->sample && wakeup_events) {
+ int events = local_inc_return(&buffer->events);
+ if (events >= wakeup_events) {
+ local_sub(wakeup_events, &buffer->events);
+ local_inc(&buffer->wakeup);
+ }
+ }
+
+ perf_output_put_handle(handle);
+ rcu_read_unlock();
+}
+
+static void
+perf_buffer_init(struct perf_buffer *buffer, long watermark, int flags)
+{
+ long max_size = perf_data_size(buffer);
+
+ if (watermark)
+ buffer->watermark = min(max_size, watermark);
+
+ if (!buffer->watermark)
+ buffer->watermark = max_size / 2;
+
+ if (flags & PERF_BUFFER_WRITABLE)
+ buffer->writable = 1;
+
+ atomic_set(&buffer->refcount, 1);
+}
+
+#ifndef CONFIG_PERF_USE_VMALLOC
+
+/*
+ * Back perf_mmap() with regular GFP_KERNEL-0 pages.
+ */
+
+struct page *
+perf_mmap_to_page(struct perf_buffer *buffer, unsigned long pgoff)
+{
+ if (pgoff > buffer->nr_pages)
+ return NULL;
+
+ if (pgoff == 0)
+ return virt_to_page(buffer->user_page);
+
+ return virt_to_page(buffer->data_pages[pgoff - 1]);
+}
+
+static void *perf_mmap_alloc_page(int cpu)
+{
+ struct page *page;
+ int node;
+
+ node = (cpu == -1) ? cpu : cpu_to_node(cpu);
+ page = alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0);
+ if (!page)
+ return NULL;
+
+ return page_address(page);
+}
+
+struct perf_buffer *
+perf_buffer_alloc(int nr_pages, long watermark, int cpu, int flags)
+{
+ struct perf_buffer *buffer;
+ unsigned long size;
+ int i;
+
+ size = sizeof(struct perf_buffer);
+ size += nr_pages * sizeof(void *);
+
+ buffer = kzalloc(size, GFP_KERNEL);
+ if (!buffer)
+ goto fail;
+
+ buffer->user_page = perf_mmap_alloc_page(cpu);
+ if (!buffer->user_page)
+ goto fail_user_page;
+
+ for (i = 0; i < nr_pages; i++) {
+ buffer->data_pages[i] = perf_mmap_alloc_page(cpu);
+ if (!buffer->data_pages[i])
+ goto fail_data_pages;
+ }
+
+ buffer->nr_pages = nr_pages;
+
+ perf_buffer_init(buffer, watermark, flags);
+
+ return buffer;
+
+fail_data_pages:
+ for (i--; i >= 0; i--)
+ free_page((unsigned long)buffer->data_pages[i]);
+
+ free_page((unsigned long)buffer->user_page);
+
+fail_user_page:
+ kfree(buffer);
+
+fail:
+ return NULL;
+}
+
+static void perf_mmap_free_page(unsigned long addr)
+{
+ struct page *page = virt_to_page((void *)addr);
+
+ page->mapping = NULL;
+ __free_page(page);
+}
+
+void perf_buffer_free(struct perf_buffer *buffer)
+{
+ int i;
+
+ perf_mmap_free_page((unsigned long)buffer->user_page);
+ for (i = 0; i < buffer->nr_pages; i++)
+ perf_mmap_free_page((unsigned long)buffer->data_pages[i]);
+ kfree(buffer);
+}
+
+#else
+
+struct page *
+perf_mmap_to_page(struct perf_buffer *buffer, unsigned long pgoff)
+{
+ if (pgoff > (1UL << perf_output_page_order(buffer)))
+ return NULL;
+
+ return vmalloc_to_page((void *)buffer->user_page + pgoff * PAGE_SIZE);
+}
+
+static void perf_mmap_unmark_page(void *addr)
+{
+ struct page *page = vmalloc_to_page(addr);
+
+ page->mapping = NULL;
+}
+
+static void perf_buffer_free_work(struct work_struct *work)
+{
+ struct perf_buffer *buffer;
+ void *base;
+ int i, nr;
+
+ buffer = container_of(work, struct perf_buffer, work);
+ nr = 1 << perf_output_page_order(buffer);
+
+ base = buffer->user_page;
+ for (i = 0; i < nr + 1; i++)
+ perf_mmap_unmark_page(base + (i * PAGE_SIZE));
+
+ vfree(base);
+ kfree(buffer);
+}
+
+void perf_buffer_free(struct perf_buffer *buffer)
+{
+ schedule_work(&buffer->work);
+}
+
+struct perf_buffer *
+perf_buffer_alloc(int nr_pages, long watermark, int cpu, int flags)
+{
+ struct perf_buffer *buffer;
+ unsigned long size;
+ void *all_buf;
+
+ size = sizeof(struct perf_buffer);
+ size += sizeof(void *);
+
+ buffer = kzalloc(size, GFP_KERNEL);
+ if (!buffer)
+ goto fail;
+
+ INIT_WORK(&buffer->work, perf_buffer_free_work);
+
+ all_buf = vmalloc_user((nr_pages + 1) * PAGE_SIZE);
+ if (!all_buf)
+ goto fail_all_buf;
+
+ buffer->user_page = all_buf;
+ buffer->data_pages[0] = all_buf + PAGE_SIZE;
+ buffer->page_order = ilog2(nr_pages);
+ buffer->nr_pages = 1;
+
+ perf_buffer_init(buffer, watermark, flags);
+
+ return buffer;
+
+fail_all_buf:
+ kfree(buffer);
+
+fail:
+ return NULL;
+}
+
+#endif
diff --git a/kernel/events/core.c b/kernel/events/core.c
index c09767f..b374fc2 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -36,6 +36,8 @@
#include <linux/ftrace_event.h>
#include <linux/hw_breakpoint.h>

+#include "internal.h"
+
#include <asm/irq_regs.h>

struct remote_function_call {
@@ -3400,216 +3402,6 @@ unlock:
rcu_read_unlock();
}

-static unsigned long perf_data_size(struct perf_buffer *buffer);
-
-static void
-perf_buffer_init(struct perf_buffer *buffer, long watermark, int flags)
-{
- long max_size = perf_data_size(buffer);
-
- if (watermark)
- buffer->watermark = min(max_size, watermark);
-
- if (!buffer->watermark)
- buffer->watermark = max_size / 2;
-
- if (flags & PERF_BUFFER_WRITABLE)
- buffer->writable = 1;
-
- atomic_set(&buffer->refcount, 1);
-}
-
-#ifndef CONFIG_PERF_USE_VMALLOC
-
-/*
- * Back perf_mmap() with regular GFP_KERNEL-0 pages.
- */
-
-static struct page *
-perf_mmap_to_page(struct perf_buffer *buffer, unsigned long pgoff)
-{
- if (pgoff > buffer->nr_pages)
- return NULL;
-
- if (pgoff == 0)
- return virt_to_page(buffer->user_page);
-
- return virt_to_page(buffer->data_pages[pgoff - 1]);
-}
-
-static void *perf_mmap_alloc_page(int cpu)
-{
- struct page *page;
- int node;
-
- node = (cpu == -1) ? cpu : cpu_to_node(cpu);
- page = alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0);
- if (!page)
- return NULL;
-
- return page_address(page);
-}
-
-static struct perf_buffer *
-perf_buffer_alloc(int nr_pages, long watermark, int cpu, int flags)
-{
- struct perf_buffer *buffer;
- unsigned long size;
- int i;
-
- size = sizeof(struct perf_buffer);
- size += nr_pages * sizeof(void *);
-
- buffer = kzalloc(size, GFP_KERNEL);
- if (!buffer)
- goto fail;
-
- buffer->user_page = perf_mmap_alloc_page(cpu);
- if (!buffer->user_page)
- goto fail_user_page;
-
- for (i = 0; i < nr_pages; i++) {
- buffer->data_pages[i] = perf_mmap_alloc_page(cpu);
- if (!buffer->data_pages[i])
- goto fail_data_pages;
- }
-
- buffer->nr_pages = nr_pages;
-
- perf_buffer_init(buffer, watermark, flags);
-
- return buffer;
-
-fail_data_pages:
- for (i--; i >= 0; i--)
- free_page((unsigned long)buffer->data_pages[i]);
-
- free_page((unsigned long)buffer->user_page);
-
-fail_user_page:
- kfree(buffer);
-
-fail:
- return NULL;
-}
-
-static void perf_mmap_free_page(unsigned long addr)
-{
- struct page *page = virt_to_page((void *)addr);
-
- page->mapping = NULL;
- __free_page(page);
-}
-
-static void perf_buffer_free(struct perf_buffer *buffer)
-{
- int i;
-
- perf_mmap_free_page((unsigned long)buffer->user_page);
- for (i = 0; i < buffer->nr_pages; i++)
- perf_mmap_free_page((unsigned long)buffer->data_pages[i]);
- kfree(buffer);
-}
-
-static inline int page_order(struct perf_buffer *buffer)
-{
- return 0;
-}
-
-#else
-
-/*
- * Back perf_mmap() with vmalloc memory.
- *
- * Required for architectures that have d-cache aliasing issues.
- */
-
-static inline int page_order(struct perf_buffer *buffer)
-{
- return buffer->page_order;
-}
-
-static struct page *
-perf_mmap_to_page(struct perf_buffer *buffer, unsigned long pgoff)
-{
- if (pgoff > (1UL << page_order(buffer)))
- return NULL;
-
- return vmalloc_to_page((void *)buffer->user_page + pgoff * PAGE_SIZE);
-}
-
-static void perf_mmap_unmark_page(void *addr)
-{
- struct page *page = vmalloc_to_page(addr);
-
- page->mapping = NULL;
-}
-
-static void perf_buffer_free_work(struct work_struct *work)
-{
- struct perf_buffer *buffer;
- void *base;
- int i, nr;
-
- buffer = container_of(work, struct perf_buffer, work);
- nr = 1 << page_order(buffer);
-
- base = buffer->user_page;
- for (i = 0; i < nr + 1; i++)
- perf_mmap_unmark_page(base + (i * PAGE_SIZE));
-
- vfree(base);
- kfree(buffer);
-}
-
-static void perf_buffer_free(struct perf_buffer *buffer)
-{
- schedule_work(&buffer->work);
-}
-
-static struct perf_buffer *
-perf_buffer_alloc(int nr_pages, long watermark, int cpu, int flags)
-{
- struct perf_buffer *buffer;
- unsigned long size;
- void *all_buf;
-
- size = sizeof(struct perf_buffer);
- size += sizeof(void *);
-
- buffer = kzalloc(size, GFP_KERNEL);
- if (!buffer)
- goto fail;
-
- INIT_WORK(&buffer->work, perf_buffer_free_work);
-
- all_buf = vmalloc_user((nr_pages + 1) * PAGE_SIZE);
- if (!all_buf)
- goto fail_all_buf;
-
- buffer->user_page = all_buf;
- buffer->data_pages[0] = all_buf + PAGE_SIZE;
- buffer->page_order = ilog2(nr_pages);
- buffer->nr_pages = 1;
-
- perf_buffer_init(buffer, watermark, flags);
-
- return buffer;
-
-fail_all_buf:
- kfree(buffer);
-
-fail:
- return NULL;
-}
-
-#endif
-
-static unsigned long perf_data_size(struct perf_buffer *buffer)
-{
- return buffer->nr_pages << (PAGE_SHIFT + page_order(buffer));
-}
-
static int perf_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
struct perf_event *event = vma->vm_file->private_data;
@@ -3892,117 +3684,6 @@ int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
}
EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);

-/*
- * Output
- */
-static bool perf_output_space(struct perf_buffer *buffer, unsigned long tail,
- unsigned long offset, unsigned long head)
-{
- unsigned long mask;
-
- if (!buffer->writable)
- return true;
-
- mask = perf_data_size(buffer) - 1;
-
- offset = (offset - tail) & mask;
- head = (head - tail) & mask;
-
- if ((int)(head - offset) < 0)
- return false;
-
- return true;
-}
-
-static void perf_output_wakeup(struct perf_output_handle *handle)
-{
- atomic_set(&handle->buffer->poll, POLL_IN);
-
- if (handle->nmi) {
- handle->event->pending_wakeup = 1;
- irq_work_queue(&handle->event->pending);
- } else
- perf_event_wakeup(handle->event);
-}
-
-/*
- * We need to ensure a later event_id doesn't publish a head when a former
- * event isn't done writing. However since we need to deal with NMIs we
- * cannot fully serialize things.
- *
- * We only publish the head (and generate a wakeup) when the outer-most
- * event completes.
- */
-static void perf_output_get_handle(struct perf_output_handle *handle)
-{
- struct perf_buffer *buffer = handle->buffer;
-
- preempt_disable();
- local_inc(&buffer->nest);
- handle->wakeup = local_read(&buffer->wakeup);
-}
-
-static void perf_output_put_handle(struct perf_output_handle *handle)
-{
- struct perf_buffer *buffer = handle->buffer;
- unsigned long head;
-
-again:
- head = local_read(&buffer->head);
-
- /*
- * IRQ/NMI can happen here, which means we can miss a head update.
- */
-
- if (!local_dec_and_test(&buffer->nest))
- goto out;
-
- /*
- * Publish the known good head. Rely on the full barrier implied
- * by atomic_dec_and_test() order the buffer->head read and this
- * write.
- */
- buffer->user_page->data_head = head;
-
- /*
- * Now check if we missed an update, rely on the (compiler)
- * barrier in atomic_dec_and_test() to re-read buffer->head.
- */
- if (unlikely(head != local_read(&buffer->head))) {
- local_inc(&buffer->nest);
- goto again;
- }
-
- if (handle->wakeup != local_read(&buffer->wakeup))
- perf_output_wakeup(handle);
-
-out:
- preempt_enable();
-}
-
-__always_inline void perf_output_copy(struct perf_output_handle *handle,
- const void *buf, unsigned int len)
-{
- do {
- unsigned long size = min_t(unsigned long, handle->size, len);
-
- memcpy(handle->addr, buf, size);
-
- len -= size;
- handle->addr += size;
- buf += size;
- handle->size -= size;
- if (!handle->size) {
- struct perf_buffer *buffer = handle->buffer;
-
- handle->page++;
- handle->page &= buffer->nr_pages - 1;
- handle->addr = buffer->data_pages[handle->page];
- handle->size = PAGE_SIZE << page_order(buffer);
- }
- } while (len);
-}
-
static void __perf_event_header__init_id(struct perf_event_header *header,
struct perf_sample_data *data,
struct perf_event *event)
@@ -4033,9 +3714,9 @@ static void __perf_event_header__init_id(struct perf_event_header *header,
}
}

-static void perf_event_header__init_id(struct perf_event_header *header,
- struct perf_sample_data *data,
- struct perf_event *event)
+void perf_event_header__init_id(struct perf_event_header *header,
+ struct perf_sample_data *data,
+ struct perf_event *event)
{
if (event->attr.sample_id_all)
__perf_event_header__init_id(header, data, event);
@@ -4062,121 +3743,14 @@ static void __perf_event__output_id_sample(struct perf_output_handle *handle,
perf_output_put(handle, data->cpu_entry);
}

-static void perf_event__output_id_sample(struct perf_event *event,
- struct perf_output_handle *handle,
- struct perf_sample_data *sample)
+void perf_event__output_id_sample(struct perf_event *event,
+ struct perf_output_handle *handle,
+ struct perf_sample_data *sample)
{
if (event->attr.sample_id_all)
__perf_event__output_id_sample(handle, sample);
}

-int perf_output_begin(struct perf_output_handle *handle,
- struct perf_event *event, unsigned int size,
- int nmi, int sample)
-{
- struct perf_buffer *buffer;
- unsigned long tail, offset, head;
- int have_lost;
- struct perf_sample_data sample_data;
- struct {
- struct perf_event_header header;
- u64 id;
- u64 lost;
- } lost_event;
-
- rcu_read_lock();
- /*
- * For inherited events we send all the output towards the parent.
- */
- if (event->parent)
- event = event->parent;
-
- buffer = rcu_dereference(event->buffer);
- if (!buffer)
- goto out;
-
- handle->buffer = buffer;
- handle->event = event;
- handle->nmi = nmi;
- handle->sample = sample;
-
- if (!buffer->nr_pages)
- goto out;
-
- have_lost = local_read(&buffer->lost);
- if (have_lost) {
- lost_event.header.size = sizeof(lost_event);
- perf_event_header__init_id(&lost_event.header, &sample_data,
- event);
- size += lost_event.header.size;
- }
-
- perf_output_get_handle(handle);
-
- do {
- /*
- * Userspace could choose to issue a mb() before updating the
- * tail pointer. So that all reads will be completed before the
- * write is issued.
- */
- tail = ACCESS_ONCE(buffer->user_page->data_tail);
- smp_rmb();
- offset = head = local_read(&buffer->head);
- head += size;
- if (unlikely(!perf_output_space(buffer, tail, offset, head)))
- goto fail;
- } while (local_cmpxchg(&buffer->head, offset, head) != offset);
-
- if (head - local_read(&buffer->wakeup) > buffer->watermark)
- local_add(buffer->watermark, &buffer->wakeup);
-
- handle->page = offset >> (PAGE_SHIFT + page_order(buffer));
- handle->page &= buffer->nr_pages - 1;
- handle->size = offset & ((PAGE_SIZE << page_order(buffer)) - 1);
- handle->addr = buffer->data_pages[handle->page];
- handle->addr += handle->size;
- handle->size = (PAGE_SIZE << page_order(buffer)) - handle->size;
-
- if (have_lost) {
- lost_event.header.type = PERF_RECORD_LOST;
- lost_event.header.misc = 0;
- lost_event.id = event->id;
- lost_event.lost = local_xchg(&buffer->lost, 0);
-
- perf_output_put(handle, lost_event);
- perf_event__output_id_sample(event, handle, &sample_data);
- }
-
- return 0;
-
-fail:
- local_inc(&buffer->lost);
- perf_output_put_handle(handle);
-out:
- rcu_read_unlock();
-
- return -ENOSPC;
-}
-
-void perf_output_end(struct perf_output_handle *handle)
-{
- struct perf_event *event = handle->event;
- struct perf_buffer *buffer = handle->buffer;
-
- int wakeup_events = event->attr.wakeup_events;
-
- if (handle->sample && wakeup_events) {
- int events = local_inc_return(&buffer->events);
- if (events >= wakeup_events) {
- local_sub(wakeup_events, &buffer->events);
- local_inc(&buffer->wakeup);
- }
- }
-
- perf_output_put_handle(handle);
- rcu_read_unlock();
-}
-
static void perf_output_read_one(struct perf_output_handle *handle,
struct perf_event *event,
u64 enabled, u64 running)
diff --git a/kernel/events/internal.h b/kernel/events/internal.h
new file mode 100644
index 0000000..2645cb9
--- /dev/null
+++ b/kernel/events/internal.h
@@ -0,0 +1,28 @@
+#ifndef _LINUX_KERNEL_EVENTS_H
+#define _LINUX_KERNEL_EVENTS_H
+
+#include <linux/perf_event.h>
+
+extern void perf_buffer_free(struct perf_buffer *buffer);
+extern struct perf_buffer *
+perf_buffer_alloc(int nr_pages, long watermark, int cpu, int flags);
+extern void perf_event_wakeup(struct perf_event *event);
+
+extern void
+perf_event_header__init_id(struct perf_event_header *header,
+ struct perf_sample_data *data,
+ struct perf_event *event);
+extern void
+perf_event__output_id_sample(struct perf_event *event,
+ struct perf_output_handle *handle,
+ struct perf_sample_data *sample);
+
+extern struct page *
+perf_mmap_to_page(struct perf_buffer *buffer, unsigned long pgoff);
+
+static unsigned long perf_data_size(struct perf_buffer *buffer)
+{
+ return buffer->nr_pages << (PAGE_SHIFT + perf_output_page_order(buffer));
+}
+
+#endif /* _LINUX_KERNEL_EVENTS_H */
--
1.7.3.2