mm: oom_kill: don't ignore oom score on exiting tasks

When the OOM killer scans tasks and encounters a PF_EXITING one, it
force-selects that task regardless of the score.  The problem is that if
that task got stuck waiting for some state the allocation site is
holding, the OOM reaper can not move on to the next best victim.

Frankly, I don't even know why we check for exiting tasks in the OOM
killer.  We've tried direct reclaim at least 15 times by the time we
decide the system is OOM, there was plenty of time to exit and free
memory; and a task might exit voluntarily right after we issue a kill.
This is testing pure noise.  Remove it.

Signed-off-by: Tetsuo Handa <[email protected]>
Signed-off-by: Johannes Weiner <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Cc: Kirill A. Shutemov <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Andrea Argangeli <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Sasha Levin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index e97a05d9621f47425a25f88fb9c0ae8fbd50004b..63ced708eafd1686feaae600fc5a13f7adb3b7c9 100644 (file)
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -287,9 +287,6 @@ enum oom_scan_t oom_scan_process_thread(struct oom_control *oc,
        if (oom_task_origin(task))
                return OOM_SCAN_SELECT;
 
-       if (task_will_free_mem(task) && !is_sysrq_oom(oc))
-               return OOM_SCAN_ABORT;
-
        return OOM_SCAN_OK;
 }