On 08/02, Rafael J. Wysocki wrote:
>
> @@ -171,6 +186,10 @@ static int try_to_freeze_tasks(int freez
>
> end_time = jiffies + TIMEOUT;
> do {
> + DEFINE_WAIT(wait);
> +
> + add_wait_queue(&refrigerator_waitq, &wait);
Hmm. In that case I'd sugest to use prepare_to_wait(). This means that
multiple wakeups from refrigerator() won't do unnecessary work, and
> +
> todo = 0;
> read_lock(&tasklist_lock);
> do_each_thread(g, p) {
> @@ -189,7 +208,12 @@ static int try_to_freeze_tasks(int freez
> todo++;
> } while_each_thread(g, p);
> read_unlock(&tasklist_lock);
> - yield(); /* Yield is okay here */
> +
> + set_current_state(TASK_UNINTERRUPTIBLE);
> + if (todo && !list_empty_careful(&wait.task_list))
> + schedule_timeout(WAIT_TIME);
we don't need to check list_empty_careful() before schedule, prepare_to_wait()
sets TASK_UNINTERRUPTIBLE under wait_queue_head_t->lock.
Still, I personally agree with Pavel. Perhaps it is better to just replace
yield() with schedule_timeout(a_bit).
Oleg.
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