Re: [PATCH 3/4] Per cgroup background reclaim.

[Ying Han <yinghan@google.com>]

On Tue, Nov 30, 2010 at 12:07 AM, KAMEZAWA Hiroyuki
<kamezawa.hiroyu@jp.fujitsu.com> wrote:
> On Tue, 30 Nov 2010 16:51:42 +0900
> KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote:
>
>> > +           if (IS_ERR(thr))
>> > +                   printk(KERN_INFO "Failed to start kswapd on memcg %d\n",
>> > +                           0);
>> > +           else
>> > +                   kswapd_p->kswapd_task = thr;
>> > +   }
>>
>> Hmm, ok, then, kswapd-for-memcg is created when someone go over watermark.
>> Why this new kswapd will not exit() until memcg destroy ?
>>
>> I think there are several approaches.
>>
>>   1. create/destroy a thread at memcg create/destroy
>>   2. create/destroy a thread at watermarks.
>>   3. use thread pool for watermarks.
>>   4. use workqueue for watermaks.
>>
>> The good point of "1" is that we can control a-thread-for-kswapd by cpu
>> controller but it will use some resource.
>> The good point of "2" is that we can avoid unnecessary resource usage.
>>
>> 3 and 4 is not very good, I think.
>>
>> I'd like to vote for "1"...I want to avoid "stealing" other container's cpu
>> by bad application in a container uses up memory.
>>
>
> One more point, one-thread-per-hierarchy is enough. So, please check
> memory.use_hierarchy==1 or not at creating a thread.

Thanks. Will take a look at it.

--Ying
>
> Thanks,
> -kame
>
>

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