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

From: Tejun Heo
Date: Wed Mar 06 2013 - 02:03:00 EST


On Tue, Mar 5, 2013 at 11:00 PM, Li Zefan <lizefan@xxxxxxxxxx> 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
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