Messages in this thread Patch in this message | | | Date | Fri, 25 Nov 2005 19:18:08 +0300 | From | Oleg Nesterov <> | Subject | [PATCH 1/2] v2 PF_DEAD: cleanup usage |
| |
schedule() checks PF_DEAD on every context switch, and sets ->state = EXIT_DEAD to ensure that exited task will be deactivated.
It is possible to set new ->state value in do_exit(), along with PF_DEAD flag, and remove the check from schedule()'s hot path.
To avoid mixing ->state/->exit_state values, this patch adds new TASK_DEAD state.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
--- 2.6.15-rc2/include/linux/sched.h~1_CLEAN 2005-11-25 20:58:09.000000000 +0300 +++ 2.6.15-rc2/include/linux/sched.h 2005-11-25 21:02:22.000000000 +0300 @@ -127,6 +127,7 @@ extern unsigned long nr_iowait(void); #define EXIT_DEAD 32 /* in tsk->state again */ #define TASK_NONINTERACTIVE 64 +#define TASK_DEAD 128 #define __set_task_state(tsk, state_value) \ do { (tsk)->state = (state_value); } while (0) --- 2.6.15-rc2/kernel/exit.c~1_CLEAN 2005-11-25 20:58:14.000000000 +0300 +++ 2.6.15-rc2/kernel/exit.c 2005-11-25 21:04:26.000000000 +0300 @@ -875,6 +875,7 @@ fastcall NORET_TYPE void do_exit(long co preempt_disable(); BUG_ON(tsk->flags & PF_DEAD); tsk->flags |= PF_DEAD; + tsk->state = TASK_DEAD; schedule(); BUG(); --- 2.6.15-rc2/kernel/sched.c~1_CLEAN 2005-11-25 20:58:14.000000000 +0300 +++ 2.6.15-rc2/kernel/sched.c 2005-11-25 21:04:48.000000000 +0300 @@ -3000,9 +3000,6 @@ 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; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |