Re: [PATCH 1/1] hung_task: Change hung_task.c to use for_each_process_thread()

Oleg Nesterov
2015-03-17T17:11:22Z

On 03/17, Aaron Tomlin wrote:
>
> --- a/kernel/hung_task.c
> +++ b/kernel/hung_task.c
> @@ -169,7 +169,7 @@ static void check_hung_uninterruptible_tasks(unsigned long timeout)
> return;
>
> rcu_read_lock();
> - do_each_thread(g, t) {
> + for_each_process_thread(g, t) {
> if (!max_count--)
> goto unlock;
> if (!--batch_count) {
> @@ -180,7 +180,7 @@ static void check_hung_uninterruptible_tasks(unsigned long timeout)
> /* use "==" to skip the TASK_KILLABLE tasks waiting on NFS */
> if (t->state == TASK_UNINTERRUPTIBLE)
> check_hung_task(t, timeout);
> - } while_each_thread(g, t);
> + }

Acked-by: Oleg Nesterov <oleg@redhat.com>

Perhaps it also makes sense to improve this rcu_lock_break a bit...
For example, if 't' is dead but 'g' is alive we can continue the
"for_each_process" part of this double loop. And if 't' is still
alive then we can find the new leader and continue...

But I agree, lets start from this fix, then we will see.

Oleg.