From 32c058d52df73f6fc087c4fb143d29904d95eb62 Mon Sep 17 00:00:00 2001 From: Michal Hocko Date: Wed, 11 Feb 2015 15:26:15 -0800 Subject: oom: thaw the OOM victim if it is frozen oom_kill_process only sets TIF_MEMDIE flag and sends a signal to the victim. This is basically noop when the task is frozen though because the task sleeps in the uninterruptible sleep. The victim is eventually thawed later when oom_scan_process_thread meets the task again in a later OOM invocation so the OOM killer doesn't live lock. But this is less than optimal. Let's add __thaw_task into mark_tsk_oom_victim after we set TIF_MEMDIE to the victim. We are not checking whether the task is frozen because that would be racy and __thaw_task does that already. oom_scan_process_thread doesn't need to care about freezer anymore as TIF_MEMDIE and freezer are excluded completely now. Change-Id: I0e1e58f06dab168d2e94f2b475e93763e73101ec Signed-off-by: Michal Hocko Cc: Tejun Heo Cc: David Rientjes Cc: Johannes Weiner Cc: Oleg Nesterov Cc: Cong Wang Cc: "Rafael J. Wysocki" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/oom_kill.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'mm') diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 6c19a8307..ad8afb380 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -278,8 +278,6 @@ enum oom_scan_t oom_scan_process_thread(struct task_struct *task, * someone new to kill. */ if (test_tsk_thread_flag(task, TIF_MEMDIE)) { - if (unlikely(frozen(task))) - __thaw_task(task); if (!force_kill) { if (time_after(jiffies, last_victim + msecs_to_jiffies(100))) { @@ -440,6 +438,14 @@ void note_oom_kill(void) void mark_tsk_oom_victim(struct task_struct *tsk) { set_tsk_thread_flag(tsk, TIF_MEMDIE); + + /* + * Make sure that the task is woken up from uninterruptible sleep + * if it is frozen because OOM killer wouldn't be able to free + * any memory and livelock. freezing_slow_path will tell the freezer + * that TIF_MEMDIE tasks should be ignored. + */ + __thaw_task(tsk); } /** -- cgit v1.2.3