Re: [feature] automatically detect hung TASK_UNINTERRUPTIBLE tasks

Ingo Molnar
2007-12-02T19:00:36Z

* Andi Kleen <andi@firstfloor.org> wrote:

> Ingo Molnar <mingo@elte.hu> writes:
>
> > this patch extends the soft-lockup detector to automatically
> > detect hung TASK_UNINTERRUPTIBLE tasks. Such hung tasks are
> > printed the following way:
>
> That will likely trigger anytime a hard nfs/cifs mount loses its
> server for 120s. To make this work you would need a new
> TASK_UNINTERRUPTIBLE_EXTERNAL_EVENT or similar and mark all the places
> which depend on those.

TASK_KILLABLE should be the right solution i think.

> I've also seen kernel modules that use semaphores like wait queues
> While that gives a little funny results (high load average) it worked
> so far, until this patch.

it still works with this patch of course. With a funny results like high
load average _AND_ a clear debug message that tells us (and the user)
where that high load average comes from.

Ingo