Re: [PATCH] workqueue: clear workers of a pool after the CPU is offline

From: Lai Jiangshan
Date: Fri Jul 26 2013 - 12:55:27 EST


On Fri, Jul 26, 2013 at 6:22 PM, Tejun Heo <tj@xxxxxxxxxx> wrote:
> On Fri, Jul 26, 2013 at 11:47:04AM +0800, Lai Jiangshan wrote:
>> any worker can't kill itself.
>> managers always tries to leave 2 workers.
>>
>> so the workers of the offline cpu pool can't be totally destroyed.
>
> But we *do* want to keep them around as CPUs taken offline are likely
> to come online at some point and destroying all of them saves only
> ~16k of memory while adding more work while CPUs are on/offlined which

4 threads, (normal and high priority wq)
~32k
it is still small.

> can be very frequent on mobile devices. The change was *intentional*.

but sometimes the cpu is offline for long time.
and maybe the adminstrator want to reclaim the resource..

Add a boot option or sysfs switch?

>
> Thanks.
>
> --
> tejun
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