[PATCH -v2] tracing: lockdep tracepoints

[Peter Zijlstra <peterz@infradead.org>]

On Wed, 2009-03-04 at 12:23 +0100, Frederic Weisbecker wrote:
> > ---
> > Subject: tracing: lockdep tracepoints
> > From: Peter Zijlstra <a.p.zijlstra@chello.nl>
> > Date: Tue Mar 03 22:03:08 CET 2009
> > 
> > Augment the traces with lock names when lockdep is available:
> > 
> >  1)               |  down_read_trylock() {
> >  1)               |    _spin_lock_irqsave() {
> >  1)               |      /* lock_acquire: name: &sem->wait_lock */
> >  1)   4.201 us    |    }
> >  1)               |    _spin_unlock_irqrestore() {
> >  1)               |      /* lock_release: name: &sem->wait_lock */
> 
> Nice idea.
> I would just suggest to drop the "name:" since the comment is intuitive enough
> to figure out what we have after lock_{release,acquire}: 

Makes sense I guess..

Here goes.. one s/name: //g later

---
Subject: tracing: lockdep tracepoints
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
Date: Tue Mar 03 22:03:08 CET 2009

Augment the traces with lock names when lockdep is available:

 1)               |  down_read_trylock() {
 1)               |    _spin_lock_irqsave() {
 1)               |      /* lock_acquire: &sem->wait_lock */
 1)   4.201 us    |    }
 1)               |    _spin_unlock_irqrestore() {
 1)               |      /* lock_release: &sem->wait_lock */
 1)   3.523 us    |    }
 1)               |  /* lock_acquire: try read &mm->mmap_sem */
 1) + 13.386 us   |  }
 1)   1.635 us    |  find_vma();
 1)               |  handle_mm_fault() {
 1)               |    __do_fault() {
 1)               |      filemap_fault() {
 1)               |        find_lock_page() {
 1)               |          find_get_page() {
 1)               |            /* lock_acquire: read rcu_read_lock */
 1)               |            /* lock_release: rcu_read_lock */
 1)   5.697 us    |          }
 1)   8.158 us    |        }
 1) + 11.079 us   |      }
 1)               |      _spin_lock() {
 1)               |        /* lock_acquire: __pte_lockptr(page) */
 1)   3.949 us    |      }
 1)   1.460 us    |      page_add_file_rmap();
 1)               |      _spin_unlock() {
 1)               |        /* lock_release: __pte_lockptr(page) */
 1)   3.115 us    |      }
 1)               |      unlock_page() {
 1)   1.421 us    |        page_waitqueue();
 1)   1.220 us    |        __wake_up_bit();
 1)   6.519 us    |      }
 1) + 34.328 us   |    }
 1) + 37.452 us   |  }
 1)               |  up_read() {
 1)               |  /* lock_release: &mm->mmap_sem */
 1)               |    _spin_lock_irqsave() {
 1)               |      /* lock_acquire: &sem->wait_lock */
 1)   3.865 us    |    }
 1)               |    _spin_unlock_irqrestore() {
 1)               |      /* lock_release: &sem->wait_lock */
 1)   8.562 us    |    }
 1) + 17.370 us   |  }

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
 include/trace/lockdep.h             |    9 +++++++
 include/trace/lockdep_event_types.h |   44 ++++++++++++++++++++++++++++++++++++
 include/trace/trace_event_types.h   |    1 
 include/trace/trace_events.h        |    1 
 kernel/lockdep.c                    |   17 +++++++++++++
 kernel/trace/trace.c                |   14 ++++++-----
 kernel/trace/trace_events_stage_3.h |    4 +--
 7 files changed, 82 insertions(+), 8 deletions(-)

Index: linux-2.6/include/trace/lockdep.h
===================================================================
--- /dev/null
+++ linux-2.6/include/trace/lockdep.h
@@ -0,0 +1,9 @@
+#ifndef _TRACE_LOCKDEP_H
+#define _TRACE_LOCKDEP_H
+
+#include <linux/lockdep.h>
+#include <linux/tracepoint.h>
+
+#include <trace/lockdep_event_types.h>
+
+#endif
Index: linux-2.6/include/trace/lockdep_event_types.h
===================================================================
--- /dev/null
+++ linux-2.6/include/trace/lockdep_event_types.h
@@ -0,0 +1,44 @@
+
+#ifndef TRACE_EVENT_FORMAT
+# error Do not include this file directly.
+# error Unless you know what you are doing.
+#endif
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM lock
+
+#ifdef CONFIG_LOCKDEP
+
+TRACE_FORMAT(lock_acquire,
+	TPPROTO(struct lockdep_map *lock, unsigned int subclass,
+		int trylock, int read, int check,
+		struct lockdep_map *next_lock, unsigned long ip),
+	TPARGS(lock, subclass, trylock, read, check, next_lock, ip),
+	TPFMT("%s%s%s", trylock ? "try " : "",
+		read ? "read " : "", lock->name)
+	);
+
+TRACE_FORMAT(lock_release,
+	TPPROTO(struct lockdep_map *lock, int nested, unsigned long ip),
+	TPARGS(lock, nested, ip),
+	TPFMT("%s", lock->name)
+	);
+
+#ifdef CONFIG_LOCK_STAT
+
+TRACE_FORMAT(lock_contended,
+	TPPROTO(struct lockdep_map *lock, unsigned long ip),
+	TPARGS(lock, ip),
+	TPFMT("%s", lock->name)
+	);
+
+TRACE_FORMAT(lock_acquired,
+	TPPROTO(struct lockdep_map *lock, unsigned long ip),
+	TPARGS(lock, ip),
+	TPFMT("%s", lock->name)
+	);
+
+#endif
+#endif
+
+#undef TRACE_SYSTEM
Index: linux-2.6/include/trace/trace_events.h
===================================================================
--- linux-2.6.orig/include/trace/trace_events.h
+++ linux-2.6/include/trace/trace_events.h
@@ -2,3 +2,4 @@
 
 #include <trace/sched.h>
 #include <trace/irq.h>
+#include <trace/lockdep.h>
Index: linux-2.6/kernel/lockdep.c
===================================================================
--- linux-2.6.orig/kernel/lockdep.c
+++ linux-2.6/kernel/lockdep.c
@@ -42,6 +42,7 @@
 #include <linux/hash.h>
 #include <linux/ftrace.h>
 #include <linux/stringify.h>
+#include <trace/lockdep.h>
 
 #include <asm/sections.h>
 
@@ -2912,6 +2913,8 @@ void lock_set_class(struct lockdep_map *
 }
 EXPORT_SYMBOL_GPL(lock_set_class);
 
+DEFINE_TRACE(lock_acquire);
+
 /*
  * We are not always called with irqs disabled - do that here,
  * and also avoid lockdep recursion:
@@ -2922,6 +2925,8 @@ void lock_acquire(struct lockdep_map *lo
 {
 	unsigned long flags;
 
+	trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip);
+
 	if (unlikely(current->lockdep_recursion))
 		return;
 
@@ -2936,11 +2941,15 @@ void lock_acquire(struct lockdep_map *lo
 }
 EXPORT_SYMBOL_GPL(lock_acquire);
 
+DEFINE_TRACE(lock_release);
+
 void lock_release(struct lockdep_map *lock, int nested,
 			  unsigned long ip)
 {
 	unsigned long flags;
 
+	trace_lock_release(lock, nested, ip);
+
 	if (unlikely(current->lockdep_recursion))
 		return;
 
@@ -3089,10 +3098,14 @@ found_it:
 	lock->ip = ip;
 }
 
+DEFINE_TRACE(lock_contended);
+
 void lock_contended(struct lockdep_map *lock, unsigned long ip)
 {
 	unsigned long flags;
 
+	trace_lock_contended(lock, ip);
+
 	if (unlikely(!lock_stat))
 		return;
 
@@ -3108,10 +3121,14 @@ void lock_contended(struct lockdep_map *
 }
 EXPORT_SYMBOL_GPL(lock_contended);
 
+DEFINE_TRACE(lock_acquired);
+
 void lock_acquired(struct lockdep_map *lock, unsigned long ip)
 {
 	unsigned long flags;
 
+	trace_lock_acquired(lock, ip);
+
 	if (unlikely(!lock_stat))
 		return;
 
Index: linux-2.6/kernel/trace/trace.c
===================================================================
--- linux-2.6.orig/kernel/trace/trace.c
+++ linux-2.6/kernel/trace/trace.c
@@ -624,7 +624,7 @@ static unsigned map_pid_to_cmdline[PID_M
 static unsigned map_cmdline_to_pid[SAVED_CMDLINES];
 static char saved_cmdlines[SAVED_CMDLINES][TASK_COMM_LEN];
 static int cmdline_idx;
-static DEFINE_SPINLOCK(trace_cmdline_lock);
+static raw_spinlock_t trace_cmdline_lock = __RAW_SPIN_LOCK_UNLOCKED;
 
 /* temporary disable recording */
 static atomic_t trace_record_cmdline_disabled __read_mostly;
@@ -736,7 +736,7 @@ static void trace_save_cmdline(struct ta
 	 * nor do we want to disable interrupts,
 	 * so if we miss here, then better luck next time.
 	 */
-	if (!spin_trylock(&trace_cmdline_lock))
+	if (!__raw_spin_trylock(&trace_cmdline_lock))
 		return;
 
 	idx = map_pid_to_cmdline[tsk->pid];
@@ -754,7 +754,7 @@ static void trace_save_cmdline(struct ta
 
 	memcpy(&saved_cmdlines[idx], tsk->comm, TASK_COMM_LEN);
 
-	spin_unlock(&trace_cmdline_lock);
+	__raw_spin_unlock(&trace_cmdline_lock);
 }
 
 char *trace_find_cmdline(int pid)
@@ -3491,7 +3491,7 @@ static __init int tracer_init_debugfs(vo
 
 int trace_vprintk(unsigned long ip, int depth, const char *fmt, va_list args)
 {
-	static DEFINE_SPINLOCK(trace_buf_lock);
+	static raw_spinlock_t trace_buf_lock = __RAW_SPIN_LOCK_UNLOCKED;
 	static char trace_buf[TRACE_BUF_SIZE];
 
 	struct ring_buffer_event *event;
@@ -3513,7 +3513,8 @@ int trace_vprintk(unsigned long ip, int 
 		goto out;
 
 	pause_graph_tracing();
-	spin_lock_irqsave(&trace_buf_lock, irq_flags);
+	raw_local_irq_save(irq_flags);
+	__raw_spin_lock(&trace_buf_lock);
 	len = vsnprintf(trace_buf, TRACE_BUF_SIZE, fmt, args);
 
 	len = min(len, TRACE_BUF_SIZE-1);
@@ -3532,7 +3533,8 @@ int trace_vprintk(unsigned long ip, int 
 	ring_buffer_unlock_commit(tr->buffer, event);
 
  out_unlock:
-	spin_unlock_irqrestore(&trace_buf_lock, irq_flags);
+	__raw_spin_unlock(&trace_buf_lock);
+	raw_local_irq_restore(irq_flags);
 	unpause_graph_tracing();
  out:
 	preempt_enable_notrace();
Index: linux-2.6/kernel/trace/trace_events_stage_3.h
===================================================================
--- linux-2.6.orig/kernel/trace/trace_events_stage_3.h
+++ linux-2.6/kernel/trace/trace_events_stage_3.h
@@ -5,7 +5,7 @@
  *
  * static void ftrace_event_<call>(proto)
  * {
- * 	event_trace_printk(_RET_IP_, "(<call>) " <fmt>);
+ * 	event_trace_printk(_RET_IP_, "<call>: " <fmt>);
  * }
  *
  * static int ftrace_reg_event_<call>(void)
@@ -112,7 +112,7 @@
 #define _TRACE_FORMAT(call, proto, args, fmt)				\
 static void ftrace_event_##call(proto)					\
 {									\
-	event_trace_printk(_RET_IP_, "(" #call ") " fmt);		\
+	event_trace_printk(_RET_IP_, #call ": " fmt);			\
 }									\
 									\
 static int ftrace_reg_event_##call(void)				\
Index: linux-2.6/include/trace/trace_event_types.h
===================================================================
--- linux-2.6.orig/include/trace/trace_event_types.h
+++ linux-2.6/include/trace/trace_event_types.h
@@ -2,3 +2,4 @@
 
 #include <trace/sched_event_types.h>
 #include <trace/irq_event_types.h>
+#include <trace/lockdep_event_types.h>