From 8540985fd2ad34b2c6e055fb2a0bb33175f50b0d Mon Sep 17 00:00:00 2001 From: Riley Andrews Date: Fri, 2 Oct 2015 00:39:53 -0700 Subject: [PATCH] ANDROID: trace: sched: add sched blocked tracepoint which dumps out context of sleep. Declare 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. Bug: 120445457 Change-Id: I19e965d5206329360a92cbfe2afcc8c30f65c229 Signed-off-by: Riley Andrews [astrachan: deleted an unnecessary whitespace change] Signed-off-by: Alistair Strachan Bug: 170916884 Signed-off-by: Todd Kjos --- include/trace/events/sched.h | 24 ++++++++++++++++++++++++ kernel/sched/fair.c | 1 + 2 files changed, 25 insertions(+) diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h index 420e80e56e55..202676bbbeb5 100644 --- a/include/trace/events/sched.h +++ b/include/trace/events/sched.h @@ -402,6 +402,30 @@ DEFINE_EVENT_SCHEDSTAT(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). diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 1847651661e8..f78a92c2b54b 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -973,6 +973,7 @@ update_stats_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