The commit is pushed to "branch-rh7-3.10.0-229.7.2.vz7.8.x-ovz" and will appear
at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-229.7.2.vz7.8.6
------>
commit 880e147721e60945828b460b86f36057e72603df
Author: Vladimir Davydov <vdavy...@parallels.com>
Date: Thu Oct 15 17:47:35 2015 +0400
ms/oom: thaw the OOM victim if it is frozen
Patchset description: oom enhancements - part 1
Pull mainstream patches that clean up TIF_MEMDIE handling. They will
come in handy for the upcoming oom rework.
https://jira.sw.ru/browse/PSBM-26973
David Rientjes (1):
mm, oom: remove unnecessary exit_state check
Johannes Weiner (1):
mm: oom_kill: clean up victim marking and exiting interfaces
Michal Hocko (3):
oom: make sure that TIF_MEMDIE is set under task_lock
oom: add helpers for setting and clearing TIF_MEMDIE
oom: thaw the OOM victim if it is frozen
Tetsuo Handa (1):
oom: don't count on mm-less current process
===============================================
This patch desciption:
From: Michal Hocko <mho...@suse.cz>
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.
Signed-off-by: Michal Hocko <mho...@suse.cz>
Cc: Tejun Heo <t...@kernel.org>
Cc: David Rientjes <rient...@google.com>
Cc: Johannes Weiner <han...@cmpxchg.org>
Cc: Oleg Nesterov <o...@redhat.com>
Cc: Cong Wang <xiyou.wangc...@gmail.com>
Cc: "Rafael J. Wysocki" <r...@rjwysocki.net>
Signed-off-by: Andrew Morton <a...@linux-foundation.org>
Signed-off-by: Linus Torvalds <torva...@linux-foundation.org>
(cherry picked from commit 63a8ca9b2084fa5bd91aa380532f18e361764109)
Signed-off-by: Vladimir Davydov <vdavy...@parallels.com>
Reviewed-by: Kirill Tkhai <ktk...@odin.com>
---
mm/oom_kill.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 224dd8d..7b106e8 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -266,8 +266,6 @@ enum oom_scan_t oom_scan_process_thread(struct task_struct
*task,
* Don't allow any other task to have access to the reserves.
*/
if (test_tsk_thread_flag(task, TIF_MEMDIE)) {
- if (unlikely(frozen(task)))
- __thaw_task(task);
if (!force_kill)
return OOM_SCAN_ABORT;
}
@@ -417,6 +415,14 @@ static void dump_header(struct task_struct *p, gfp_t
gfp_mask, int order,
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);
}
/**
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