From: Michal Hocko <mhocko@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>,
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>,
Michal Hocko <mhocko@suse.com>
Subject: [PATCH] mm, oom: document oom_lock
Date: Wed, 11 Jul 2018 14:01:21 +0200 [thread overview]
Message-ID: <20180711120121.25635-1-mhocko@kernel.org> (raw)
From: Michal Hocko <mhocko@suse.com>
Add a short documentation about what is the oom_lock scope.
Requested-by: David Rientjes <rientjes@google.com>
Signed-off-by: Michal Hocko <mhocko@suse.com>
---
mm/oom_kill.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index ed9d473c571e..32e6f7becb40 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -53,6 +53,14 @@ int sysctl_panic_on_oom;
int sysctl_oom_kill_allocating_task;
int sysctl_oom_dump_tasks = 1;
+/*
+ * Serializes oom killer invocations (out_of_memory()) from all contexts to
+ * prevent from over eager oom killing (e.g. when the oom killer is invoked
+ * from different domains).
+ *
+ * oom_killer_disable() relies on this lock to stabilize oom_killer_disabled
+ * and mark_oom_victim
+ */
DEFINE_MUTEX(oom_lock);
#ifdef CONFIG_NUMA
--
2.18.0
reply other threads:[~2018-07-11 12:01 UTC|newest]
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