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| author | Oleg Nesterov <oleg@tv-sign.ru> | 2006-09-29 02:01:09 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-09-29 09:18:20 -0700 |
| commit | 29b884921634e1e01cbd276e1c9b8fc07a7e4a90 (patch) | |
| tree | 951fce8626715b1ad26ca81bec9002cfcb8242af /kernel | |
| parent | e8106b941ceab68cc5ff713df7b1276484554584 (diff) | |
| download | blackbird-op-linux-29b884921634e1e01cbd276e1c9b8fc07a7e4a90.tar.gz blackbird-op-linux-29b884921634e1e01cbd276e1c9b8fc07a7e4a90.zip | |
[PATCH] set EXIT_DEAD state in do_exit(), not in schedule()
schedule() checks PF_DEAD on every context switch and sets ->state = EXIT_DEAD
to ensure that the exiting task will be deactivated. Note that this EXIT_DEAD
is in fact a "random" value, we can use any bit except normal TASK_XXX values.
It is better to set this state in do_exit() along with PF_DEAD flag and remove
that check in schedule().
We are safe wrt concurrent try_to_wake_up() (for example ptrace, tkill), it
can not change task's ->state: the 'state' argument of try_to_wake_up() can't
have EXIT_DEAD bit. And in case when try_to_wake_up() sees a stale value of
->state == TASK_RUNNING it will do nothing.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/exit.c | 1 | ||||
| -rw-r--r-- | kernel/sched.c | 3 |
2 files changed, 1 insertions, 3 deletions
diff --git a/kernel/exit.c b/kernel/exit.c index 4a280856acd2..3d759c98fb11 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -957,6 +957,7 @@ fastcall NORET_TYPE void do_exit(long code) preempt_disable(); BUG_ON(tsk->flags & PF_DEAD); tsk->flags |= PF_DEAD; + tsk->state = EXIT_DEAD; schedule(); BUG(); diff --git a/kernel/sched.c b/kernel/sched.c index 155a33da7aa7..e1646b044b69 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -3348,9 +3348,6 @@ need_resched_nonpreemptible: spin_lock_irq(&rq->lock); - if (unlikely(prev->flags & PF_DEAD)) - prev->state = EXIT_DEAD; - switch_count = &prev->nivcsw; if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { switch_count = &prev->nvcsw; |
