linux-kernel - Re: [PATCH v2 0/5] mm: support parallel free of memory

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Date:   Tue, 21 Mar 2017 11:18:16 -0400
From:   Tim Chen <tim.c.chen@...ux.intel.com>
To:     Michal Hocko <mhocko@...nel.org>
Cc:     Aaron Lu <aaron.lu@...el.com>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, Dave Hansen <dave.hansen@...el.com>,
        Tim Chen <tim.c.chen@...el.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Ying Huang <ying.huang@...el.com>
Subject: Re: [PATCH v2 0/5] mm: support parallel free of memory

On Thu, 2017-03-16 at 10:07 +0100, Michal Hocko wrote:
> 
> > > the main problem is that kworkers will not belong to the same cpu group
> > > and so they will not be throttled properly.
> > You do have a point that this page freeing activities should strive to
> > affect other threads not in the same cgroup minimally.
> > 
> > On the other hand, we also don't do this throttling of kworkers 
> > today (e.g. pdflush) according to the cgroup it is doing work for.
> Yes, I am not saying this a new problem. I just wanted to point out that
> this is something to consider here. I believe this should be fixable.
> Worker can attach to the same cgroup the initiator had for example
> (assuming the cgroup core allows that which is something would have to
> be checked).

Instead of attaching the kworders to the cgroup of the initiator, I
wonder what people think about creating a separate kworker cgroup. 
The administrator can set limit on its cpu resource bandwidth
if he/she does not want such kworkers perturbing the system.

Tim