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Commit 0627fa13 authored by Riley Andrews's avatar Riley Andrews
Browse files

sched: add sched blocked tracepoint which dumps out context of sleep. 



Decare war on uninterruptible sleep. Add a tracepoint which
walks the kernel stack and dumps the first non-scheduler function
called before the scheduler is invoked.

Change-Id: I19e965d5206329360a92cbfe2afcc8c30f65c229
Signed-off-by: default avatarRiley Andrews <riandrews@google.com>
parent 3c12649e

include/trace/events/sched.h

+25 −1
Original line number Diff line number Diff line
@@ -361,6 +361,30 @@ DEFINE_EVENT(sched_stat_template, sched_stat_blocked, 
	     TP_PROTO(struct task_struct *tsk, u64 delay),

	     TP_ARGS(tsk, delay));



/*

 * Tracepoint for recording the cause of uninterruptible sleep.

 */

TRACE_EVENT(sched_blocked_reason,



	TP_PROTO(struct task_struct *tsk),



	TP_ARGS(tsk),



	TP_STRUCT__entry(

		__field( pid_t,	pid	)

		__field( void*, caller	)

		__field( bool, io_wait	)

	),



	TP_fast_assign(

		__entry->pid	= tsk->pid;

		__entry->caller = (void*)get_wchan(tsk);

		__entry->io_wait = tsk->in_iowait;

	),



	TP_printk("pid=%d iowait=%d caller=%pS", __entry->pid, __entry->io_wait, __entry->caller)

);



/*

 * Tracepoint for accounting runtime (time the task is executing

 * on a CPU).

kernel/sched/fair.c

+1 −0
Original line number Diff line number Diff line
@@ -2747,6 +2747,7 @@ static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se) 
			}



			trace_sched_stat_blocked(tsk, delta);

			trace_sched_blocked_reason(tsk);



			/*

			 * Blocking time is in units of nanosecs, so shift by