Re: [PATCH v2 3/5] mm: use a dedicated workqueue for the free workers

From: Dave Hansen
Date: Thu Mar 23 2017 - 11:38:49 EST


On 03/22/2017 01:41 AM, Aaron Lu wrote:
> On Wed, Mar 22, 2017 at 03:33:35PM +0900, Minchan Kim wrote:
>> On Wed, Mar 15, 2017 at 05:00:02PM +0800, Aaron Lu wrote:
>>> Introduce a workqueue for all the free workers so that user can fine
>>> tune how many workers can be active through sysfs interface: max_active.
>>> More workers will normally lead to better performance, but too many can
>>> cause severe lock contention.
>>
>> Let me ask a question.
>>
>> How well can workqueue distribute the jobs in multiple CPU?
>
> I would say it's good enough for my needs.
> After all, it doesn't need many kworkers to achieve the 50% time
> decrease: 2-4 kworkers for EP and 4-8 kworkers for EX are enough from
> previous attched data.

It's also worth noting that we'd like to *also* like to look into
increasing how scalable freeing pages to a given zone is.