From: Ingo Molnar <mingo@elte.hu>
Date: Mon, 12 May 2008 19:20:41 +0000 (+0200)
Subject: sched: add latency tracer callbacks to the scheduler
X-Git-Tag: v2.6.27-rc1~1102^2^2~1^2~158
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=bd3bff9e20f454b242d979ec2f9a4dca0d5fa06f;p=linux-2.6

sched: add latency tracer callbacks to the scheduler

add 3 lightweight callbacks to the tracer backend.

zero impact if tracing is turned off.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 5395a6176f..717cab8a0c 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2117,6 +2117,32 @@ static inline void arch_pick_mmap_layout(struct mm_struct *mm)
 }
 #endif
 
+#ifdef CONFIG_CONTEXT_SWITCH_TRACER
+extern void
+ftrace_ctx_switch(struct task_struct *prev, struct task_struct *next);
+#else
+static inline void
+ftrace_ctx_switch(struct task_struct *prev, struct task_struct *next)
+{
+}
+#endif
+
+#ifdef CONFIG_SCHED_TRACER
+extern void
+ftrace_wake_up_task(struct task_struct *wakee, struct task_struct *curr);
+extern void
+ftrace_wake_up_new_task(struct task_struct *wakee, struct task_struct *curr);
+#else
+static inline void
+ftrace_wake_up_task(struct task_struct *wakee, struct task_struct *curr)
+{
+}
+static inline void
+ftrace_wake_up_new_task(struct task_struct *wakee, struct task_struct *curr)
+{
+}
+#endif
+
 extern long sched_setaffinity(pid_t pid, const cpumask_t *new_mask);
 extern long sched_getaffinity(pid_t pid, cpumask_t *mask);
 
diff --git a/kernel/sched.c b/kernel/sched.c
index cfa222a915..463dcdb36e 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2467,6 +2467,7 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync)
 
 out_activate:
 #endif /* CONFIG_SMP */
+	ftrace_wake_up_task(p, rq->curr);
 	schedstat_inc(p, se.nr_wakeups);
 	if (sync)
 		schedstat_inc(p, se.nr_wakeups_sync);
@@ -2611,6 +2612,7 @@ void wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
 		p->sched_class->task_new(rq, p);
 		inc_nr_running(rq);
 	}
+	ftrace_wake_up_new_task(p, rq->curr);
 	check_preempt_curr(rq, p);
 #ifdef CONFIG_SMP
 	if (p->sched_class->task_wake_up)
@@ -2783,6 +2785,7 @@ context_switch(struct rq *rq, struct task_struct *prev,
 	struct mm_struct *mm, *oldmm;
 
 	prepare_task_switch(rq, prev, next);
+	ftrace_ctx_switch(prev, next);
 	mm = next->mm;
 	oldmm = prev->active_mm;
 	/*