AcoSail/kernel_optimize_test
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move exit_task_work() past exit_files() et.al.

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... and get rid of PF_EXITING check in task_work_add().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2012-06-27 11:31:24 +04:00
parent 67d1214551
commit ed3e694d78
2 changed files with 13 additions and 23 deletions
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6
kernel/exit.c
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@ -953,14 +953,11 @@ void do_exit(long code)
exit_signals(tsk); /* sets PF_EXITING */
/*
* tsk->flags are checked in the futex code to protect against
* an exiting task cleaning up the robust pi futexes, and in
* task_work_add() to avoid the race with exit_task_work().
* an exiting task cleaning up the robust pi futexes.
*/
smp_mb();
raw_spin_unlock_wait(&tsk->pi_lock);
exit_task_work(tsk);
if (unlikely(in_atomic()))
printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n",
current->comm, task_pid_nr(current),
@ -995,6 +992,7 @@ void do_exit(long code)
exit_shm(tsk);
exit_files(tsk);
exit_fs(tsk);
exit_task_work(tsk);
check_stack_usage();
exit_thread();

30
kernel/task_work.c
View File

@ -5,34 +5,26 @@
int
task_work_add(struct task_struct *task, struct callback_head *twork, bool notify)
{
struct callback_head *last, *first;
unsigned long flags;
int err = -ESRCH;
#ifndef TIF_NOTIFY_RESUME
if (notify)
return -ENOTSUPP;
#endif
/*
* We must not insert the new work if the task has already passed
* exit_task_work(). We rely on do_exit()->raw_spin_unlock_wait()
* and check PF_EXITING under pi_lock.
* Not inserting the new work if the task has already passed
* exit_task_work() is the responisbility of callers.
*/
raw_spin_lock_irqsave(&task->pi_lock, flags);
if (likely(!(task->flags & PF_EXITING))) {
struct callback_head *last = task->task_works;
struct callback_head *first = last ? last->next : twork;
twork->next = first;
if (last)
last->next = twork;
task->task_works = twork;
err = 0;
}
last = task->task_works;
first = last ? last->next : twork;
twork->next = first;
if (last)
last->next = twork;
task->task_works = twork;
raw_spin_unlock_irqrestore(&task->pi_lock, flags);
/* test_and_set_bit() implies mb(), see tracehook_notify_resume(). */
if (likely(!err) && notify)
if (notify)
set_notify_resume(task);
return err;
return 0;
}
struct callback_head *