mm-oom_kill-fix-the-wrong-task-mm-==-mm-checks-in-oom_kill_process-fix

document process_shares_mm() a bit

Cc: David Rientjes <rientjes@google.com>
Cc: Kyle Walker <kwalker@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Stanislav Kozina <skozina@redhat.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 52abb78633d54509db9015710220f097042152ac..d13a33918fa23e685bc629bc23f58d97729beb62 100644 (file)
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -483,6 +483,12 @@ void oom_killer_enable(void)
        oom_killer_disabled = false;
 }
 
+/*
+ * task->mm can be NULL if the task is the exited group leader.  So to
+ * determine whether the task is using a particular mm, we examine all the
+ * task's threads: if one of those is using this mm then this task was also
+ * using it.
+ */
 static bool process_shares_mm(struct task_struct *p, struct mm_struct *mm)
 {
        struct task_struct *t;