lkml.org 
[lkml]   [2005]   [Nov]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
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/
\
 
 \ /
  Last update: 2005-11-25 16:05    [W:0.241 / U:0.032 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site