Re: [PATCH 3/2] fix flush_workqueue() vs CPU_DEAD race

From: Gautham R Shenoy
Date: Wed Jan 03 2007 - 23:37:29 EST


On Wed, Jan 03, 2007 at 08:26:57PM +0300, Oleg Nesterov wrote:
>
> I thought that these patches don't depend on each other, flush_work/workueue
> don't care where cpu-hotplug takes workqueue_mutex, in CPU_LOCK_ACQUIRE or in
> CPU_UP_PREPARE case (or CPU_DEAD/CPU_LOCK_RELEASE for unlock).
>
> Could you clarify? Just curious.

You are right. They don't depend on each other.

The intention behind introducing CPU_LOCK_ACQUIRE and CPU_LOCK_RELEASE
was to have a standard place where the subsystems could acquire/release
the "cpu hotplug protection" mutex in the cpu_hotplug callback function.

The same can be acheived by acquiring these mutexes in
CPU_UP_PREPARE/CPU_DOWN_PREPARE etc.

This is true for every subsystem that is cpu-hotplug aware.

> Oleg.
>

Thanks and Regards
gautham.
--
Gautham R Shenoy
Linux Technology Center
IBM India.
"Freedom comes with a price tag of responsibility, which is still a bargain,
because Freedom is priceless!"
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