[PATCH] select_bad_process(): kill a bogus PF_DEAD/TASK_DEAD check
The only one usage of TASK_DEAD outside of last schedule path,
select_bad_process:
for_each_task(p) {
if (!p->mm)
continue;
...
if (p->state == TASK_DEAD)
continue;
...
TASK_DEAD state is set at the end of do_exit(), this means that p->mm
was already set == NULL by exit_mm(), so this task was already rejected
by 'if (!p->mm)' above.
Note also that the caller holds tasklist_lock, this means that p can't
pass exit_notify() and then set TASK_DEAD when p->mm != NULL.
Also, remove open-coded is_init().
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 21f0a7e..423dcae 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -206,11 +206,14 @@
unsigned long points;
int releasing;
- /* skip kernel threads */
+ /*
+ * skip kernel threads and tasks which have already released
+ * their mm.
+ */
if (!p->mm)
continue;
- /* skip the init task with pid == 1 */
- if (p->pid == 1)
+ /* skip the init task */
+ if (is_init(p))
continue;
/*
@@ -226,9 +229,6 @@
releasing = test_tsk_thread_flag(p, TIF_MEMDIE) ||
p->flags & PF_EXITING;
if (releasing) {
- /* TASK_DEAD tasks have already released their mm */
- if (p->state == TASK_DEAD)
- continue;
if (p->flags & PF_EXITING && p == current) {
chosen = p;
*ppoints = ULONG_MAX;