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Date: Wed, 4 Mar 2009 12:23:46 +0100
From: Frederic Weisbecker <fweisbec@...il.com>
To: Peter Zijlstra <peterz@...radead.org>
Cc: Steven Rostedt <rostedt@...dmis.org>, Ingo Molnar <mingo@...e.hu>,
Török Edwin <edwintorok@...il.com>,
Jason Baron <jbaron@...hat.com>,
lkml <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] tracing: lockdep tracepoints
On Wed, Mar 04, 2009 at 12:03:06PM +0100, Peter Zijlstra wrote:
> Lets add LKML this time :-)
>
> ---
> Subject: tracing: lockdep tracepoints
> From: Peter Zijlstra <a.p.zijlstra@...llo.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}:
Frederic.
> 1) 3.523 us | }
> 1) | /* lock_acquire: try read name: &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 name: rcu_read_lock */
> 1) | /* lock_release: name: rcu_read_lock */
> 1) 5.697 us | }
> 1) 8.158 us | }
> 1) + 11.079 us | }
> 1) | _spin_lock() {
> 1) | /* lock_acquire: name: __pte_lockptr(page) */
> 1) 3.949 us | }
> 1) 1.460 us | page_add_file_rmap();
> 1) | _spin_unlock() {
> 1) | /* lock_release: name: __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: name: &mm->mmap_sem */
> 1) | _spin_lock_irqsave() {
> 1) | /* lock_acquire: name: &sem->wait_lock */
> 1) 3.865 us | }
> 1) | _spin_unlock_irqrestore() {
> 1) | /* lock_release: name: &sem->wait_lock */
> 1) 8.562 us | }
> 1) + 17.370 us | }
>
> Signed-off-by: Peter Zijlstra <a.p.zijlstra@...llo.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%sname: %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("name: %s", lock->name)
> + );
> +
> +#ifdef CONFIG_LOCK_STAT
> +
> +TRACE_FORMAT(lock_contended,
> + TPPROTO(struct lockdep_map *lock, unsigned long ip),
> + TPARGS(lock, ip),
> + TPFMT("name: %s", lock->name)
> + );
> +
> +TRACE_FORMAT(lock_acquired,
> + TPPROTO(struct lockdep_map *lock, unsigned long ip),
> + TPARGS(lock, ip),
> + TPFMT("name: %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>
>
>
> --
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