From: Tejun Heo <tj@kernel.org>
To: Dave Chinner <david@fromorbit.com>
Cc: Michal Hocko <mhocko@kernel.org>,
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
linux-xfs@vger.kernel.org, linux-mm@kvack.org
Subject: Re: How to favor memory allocations for WQ_MEM_RECLAIM threads?
Date: Wed, 8 Mar 2017 18:03:27 -0500 [thread overview]
Message-ID: <20170308230327.GE21117@htj.duckdns.org> (raw)
In-Reply-To: <20170307214842.GA7500@htj.duckdns.org>
Hello,
On Tue, Mar 07, 2017 at 04:48:42PM -0500, Tejun Heo wrote:
> > > It's implementable for sure. I'm just not sure how it'd help
> > > anything. It's not a relevant information on anything.
> >
> > Except to enable us to get closer to the "rescuer must make forwards
> > progress" guarantee. In this context, the rescuer is the only
> > context we should allow to dip into memory reserves. I'm happy if we
> > have to explicitly check for that and set PF_MEMALLOC ourselves
> > (we do that for XFS kernel threads involved in memory reclaim),
> > but it's not something we should set automatically on every
> > IO completion work item we run....
>
> Ah, okay, that does make sense to me. Yeah, providing that test
> shouldn't be difficult at all. Lemme cook up a patch.
Turns out we already have this. Writeback path already has a special
case handling for the rescuer. You can just use
current_is_workqueue_rescuer(). The function can be called safely
from any task context.
Thanks.
--
tejun
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prev parent reply other threads:[~2017-03-08 23:03 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-03 10:48 How to favor memory allocations for WQ_MEM_RECLAIM threads? Tetsuo Handa
2017-03-03 13:39 ` Michal Hocko
2017-03-03 15:37 ` Brian Foster
2017-03-03 15:52 ` Michal Hocko
2017-03-03 17:29 ` Brian Foster
2017-03-04 14:54 ` Tetsuo Handa
2017-03-06 13:25 ` Brian Foster
2017-03-06 16:08 ` Tetsuo Handa
2017-03-06 16:17 ` Brian Foster
2017-03-03 23:25 ` Dave Chinner
2017-03-07 12:15 ` Michal Hocko
2017-03-07 19:36 ` Tejun Heo
2017-03-07 21:21 ` Dave Chinner
2017-03-07 21:48 ` Tejun Heo
2017-03-08 23:03 ` Tejun Heo [this message]
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