Re: [PATCH] cgroup: make cgrp->event_list_lock irqsafe

Tejun Heo
2013-03-06T07:02:53Z

On Tue, Mar 5, 2013 at 11:00 PM, Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org> wrote:
>> Why should wqh->lock be hard-irq-safe? Is it actually grabbed from
>> irq context?
>
> becase cgroup_event_wake() is a callback to a wait queue, and it's wake_up()
> that acquires wqh->lock with irq disabled.

So, acquiring a lock with irq disabled doesn't make it a irq lock.
Being grabbed *from* irq handler makes it a irq lock. Would the
wake_up() happen from irq handler?

Thanks.

--
tejun