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authorMichal Hocko <mhocko@suse.com>2016-03-25 14:20:27 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-03-25 16:37:42 -0700
commit36324a990cf578b57828c04cd85ac62cd25cf5a4 (patch)
tree69480f4bf3a00a32ddf2d4a9a7fd67bbe45a3c0b /include
parentaac453635549699c13a84ea1456d5b0e574ef855 (diff)
oom: clear TIF_MEMDIE after oom_reaper managed to unmap the address space
When oom_reaper manages to unmap all the eligible vmas there shouldn't be much of the freable memory held by the oom victim left anymore so it makes sense to clear the TIF_MEMDIE flag for the victim and allow the OOM killer to select another task. The lack of TIF_MEMDIE also means that the victim cannot access memory reserves anymore but that shouldn't be a problem because it would get the access again if it needs to allocate and hits the OOM killer again due to the fatal_signal_pending resp. PF_EXITING check. We can safely hide the task from the OOM killer because it is clearly not a good candidate anymore as everyhing reclaimable has been torn down already. This patch will allow to cap the time an OOM victim can keep TIF_MEMDIE and thus hold off further global OOM killer actions granted the oom reaper is able to take mmap_sem for the associated mm struct. This is not guaranteed now but further steps should make sure that mmap_sem for write should be blocked killable which will help to reduce such a lock contention. This is not done by this patch. Note that exit_oom_victim might be called on a remote task from __oom_reap_task now so we have to check and clear the flag atomically otherwise we might race and underflow oom_victims or wake up waiters too early. Signed-off-by: Michal Hocko <mhocko@suse.com> Suggested-by: Johannes Weiner <hannes@cmpxchg.org> Suggested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Andrea Argangeli <andrea@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/oom.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/oom.h b/include/linux/oom.h
index 03e6257321f0..45993b840ed6 100644
--- a/include/linux/oom.h
+++ b/include/linux/oom.h
@@ -91,7 +91,7 @@ extern enum oom_scan_t oom_scan_process_thread(struct oom_control *oc,
extern bool out_of_memory(struct oom_control *oc);
-extern void exit_oom_victim(void);
+extern void exit_oom_victim(struct task_struct *tsk);
extern int register_oom_notifier(struct notifier_block *nb);
extern int unregister_oom_notifier(struct notifier_block *nb);