Add tracepoints to simplify the debugging of the oom reaper code. Trace the following events: 1) a process is marked as an oom victim, 2) a process is added to the oom reaper list, 3) the oom reaper starts reaping process's mm, 4) the oom reaper finished reaping, 5) the oom reaper skips reaping.
Signed-off-by: Roman Gushchin <[email protected]> Cc: Michal Hocko <[email protected]> Cc: Tetsuo Handa <[email protected]> Cc: Johannes Weiner <[email protected]> Cc: Vladimir Davydov <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] --- include/trace/events/oom.h | 80 ++++++++++++++++++++++++++++++++++++++++++++++ mm/oom_kill.c | 7 ++++ 2 files changed, 87 insertions(+) diff --git a/include/trace/events/oom.h b/include/trace/events/oom.h index 38baeb2..c3c19d4 100644 --- a/include/trace/events/oom.h +++ b/include/trace/events/oom.h @@ -70,6 +70,86 @@ TRACE_EVENT(reclaim_retry_zone, __entry->wmark_check) ); +TRACE_EVENT(mark_victim, + TP_PROTO(int pid), + + TP_ARGS(pid), + + TP_STRUCT__entry( + __field(int, pid) + ), + + TP_fast_assign( + __entry->pid = pid; + ), + + TP_printk("pid=%d", __entry->pid) +); + +TRACE_EVENT(wake_reaper, + TP_PROTO(int pid), + + TP_ARGS(pid), + + TP_STRUCT__entry( + __field(int, pid) + ), + + TP_fast_assign( + __entry->pid = pid; + ), + + TP_printk("pid=%d", __entry->pid) +); + +TRACE_EVENT(start_task_reaping, + TP_PROTO(int pid), + + TP_ARGS(pid), + + TP_STRUCT__entry( + __field(int, pid) + ), + + TP_fast_assign( + __entry->pid = pid; + ), + + TP_printk("pid=%d", __entry->pid) +); + +TRACE_EVENT(finish_task_reaping, + TP_PROTO(int pid), + + TP_ARGS(pid), + + TP_STRUCT__entry( + __field(int, pid) + ), + + TP_fast_assign( + __entry->pid = pid; + ), + + TP_printk("pid=%d", __entry->pid) +); + +TRACE_EVENT(skip_task_reaping, + TP_PROTO(int pid), + + TP_ARGS(pid), + + TP_STRUCT__entry( + __field(int, pid) + ), + + TP_fast_assign( + __entry->pid = pid; + ), + + TP_printk("pid=%d", __entry->pid) +); + #ifdef CONFIG_COMPACTION TRACE_EVENT(compact_retry, diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 04c9143..409b685 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -490,6 +490,7 @@ static bool __oom_reap_task_mm(struct task_struct *tsk, struct mm_struct *mm) if (!down_read_trylock(&mm->mmap_sem)) { ret = false; + trace_skip_task_reaping(tsk->pid); goto unlock_oom; } @@ -500,9 +501,12 @@ static bool __oom_reap_task_mm(struct task_struct *tsk, struct mm_struct *mm) */ if (!mmget_not_zero(mm)) { up_read(&mm->mmap_sem); + trace_skip_task_reaping(tsk->pid); goto unlock_oom; } + trace_start_task_reaping(tsk->pid); + /* * Tell all users of get_user/copy_from_user etc... that the content * is no longer stable. No barriers really needed because unmapping @@ -544,6 +548,7 @@ static bool __oom_reap_task_mm(struct task_struct *tsk, struct mm_struct *mm) * put the oom_reaper out of the way. */ mmput_async(mm); + trace_finish_task_reaping(tsk->pid); unlock_oom: mutex_unlock(&oom_lock); return ret; @@ -615,6 +620,7 @@ static void wake_oom_reaper(struct task_struct *tsk) tsk->oom_reaper_list = oom_reaper_list; oom_reaper_list = tsk; spin_unlock(&oom_reaper_lock); + trace_wake_reaper(tsk->pid); wake_up(&oom_reaper_wait); } @@ -666,6 +672,7 @@ static void mark_oom_victim(struct task_struct *tsk) */ __thaw_task(tsk); atomic_inc(&oom_victims); + trace_mark_victim(tsk->pid); } /** -- 2.7.4
