[17/63] oom: skip zombies when iterating tasklist

From: Greg KH
Date: Fri Mar 25 2011 - 20:26:16 EST


2.6.38-stable review patch. If anyone has any objections, please let us know.

------------------

From: Andrey Vagin <avagin@xxxxxxxxxx>

commit 30e2b41f20b6238f51e7cffb879c7a0f0073f5fe upstream.

We shouldn't defer oom killing if a thread has already detached its ->mm
and still has TIF_MEMDIE set. Memory needs to be freed, so find kill
other threads that pin the same ->mm or find another task to kill.

Signed-off-by: Andrey Vagin <avagin@xxxxxxxxxx>
Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
mm/oom_kill.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -299,6 +299,8 @@ static struct task_struct *select_bad_pr
do_each_thread(g, p) {
unsigned int points;

+ if (!p->mm)
+ continue;
if (oom_unkillable_task(p, mem, nodemask))
continue;

@@ -324,7 +326,7 @@ static struct task_struct *select_bad_pr
* the process of exiting and releasing its resources.
* Otherwise we could get an easy OOM deadlock.
*/
- if ((p->flags & PF_EXITING) && p->mm) {
+ if (p->flags & PF_EXITING) {
if (p != current)
return ERR_PTR(-1UL);



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