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From: Tejun Heo <tj@kernel.org>
To: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
	Michal Hocko <mhocko@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Roman Gushchin <guro@fb.com>,
	linux-mm@kvack.org, cgroups@vger.kernel.org,
	linux-kernel@vger.kernel.org, kernel-team@fb.com,
	Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH] mm: memcontrol: asynchronous reclaim for memory.high
Date: Thu, 20 Feb 2020 13:45:45 -0500	[thread overview]
Message-ID: <20200220184545.GH698990@mtj.thefacebook.com> (raw)
In-Reply-To: <20200220182326.ubcjycaubgykiy6e@ca-dmjordan1.us.oracle.com>

Hello,

On Thu, Feb 20, 2020 at 01:23:26PM -0500, Daniel Jordan wrote:
> The amount of work wouldn't seem to matter as long as the kernel thread stays
> in the cgroup and lives long enough.  There's only the one-time cost of
> attaching it when it's forked.  That seems doable for unbound workqueues (the
> async reclaim), but may not be for the network packets.

The setup cost can be lazy optimized but it'd still have to bounce the
tiny pieces of work to different threads instead of processing them in
one fell swoop from the same context, which most likely is gonna be
untenably expensive.

Thanks.

-- 
tejun

WARNING: multiple messages have this Message-ID (diff)
From: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
To: Daniel Jordan <daniel.m.jordan-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
Cc: Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>,
	Michal Hocko <mhocko-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Andrew Morton
	<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
	Roman Gushchin <guro-b10kYP2dOMg@public.gmane.org>,
	linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org,
	cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	kernel-team-b10kYP2dOMg@public.gmane.org,
	Peter Zijlstra <peterz-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
Subject: Re: [PATCH] mm: memcontrol: asynchronous reclaim for memory.high
Date: Thu, 20 Feb 2020 13:45:45 -0500	[thread overview]
Message-ID: <20200220184545.GH698990@mtj.thefacebook.com> (raw)
In-Reply-To: <20200220182326.ubcjycaubgykiy6e-S51bK0XF4qpuJJETbFA3a0B3C2bhBk7L0E9HWUfgJXw@public.gmane.org>

Hello,

On Thu, Feb 20, 2020 at 01:23:26PM -0500, Daniel Jordan wrote:
> The amount of work wouldn't seem to matter as long as the kernel thread stays
> in the cgroup and lives long enough.  There's only the one-time cost of
> attaching it when it's forked.  That seems doable for unbound workqueues (the
> async reclaim), but may not be for the network packets.

The setup cost can be lazy optimized but it'd still have to bounce the
tiny pieces of work to different threads instead of processing them in
one fell swoop from the same context, which most likely is gonna be
untenably expensive.

Thanks.

-- 
tejun

  reply	other threads:[~2020-02-20 18:45 UTC|newest]

Thread overview: 56+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-19 18:12 [PATCH] mm: memcontrol: asynchronous reclaim for memory.high Johannes Weiner
2020-02-19 18:12 ` Johannes Weiner
2020-02-19 18:37 ` Michal Hocko
2020-02-19 18:37   ` Michal Hocko
2020-02-19 19:16   ` Johannes Weiner
2020-02-19 19:16     ` Johannes Weiner
2020-02-19 19:53     ` Michal Hocko
2020-02-19 19:53       ` Michal Hocko
2020-02-19 21:17       ` Johannes Weiner
2020-02-20  9:46         ` Michal Hocko
2020-02-20  9:46           ` Michal Hocko
2020-02-20 14:41           ` Johannes Weiner
2020-02-20 14:41             ` Johannes Weiner
2020-02-19 21:41       ` Daniel Jordan
2020-02-19 21:41         ` Daniel Jordan
2020-02-19 22:08         ` Johannes Weiner
2020-02-19 22:08           ` Johannes Weiner
2020-02-20 15:45           ` Daniel Jordan
2020-02-20 15:45             ` Daniel Jordan
2020-02-20 15:56             ` Tejun Heo
2020-02-20 15:56               ` Tejun Heo
2020-02-20 18:23               ` Daniel Jordan
2020-02-20 18:23                 ` Daniel Jordan
2020-02-20 18:45                 ` Tejun Heo [this message]
2020-02-20 18:45                   ` Tejun Heo
2020-02-20 19:55                   ` Daniel Jordan
2020-02-20 19:55                     ` Daniel Jordan
2020-02-20 20:54                     ` Tejun Heo
2020-02-20 20:54                       ` Tejun Heo
2020-02-19 19:17   ` Chris Down
2020-02-19 19:17     ` Chris Down
2020-02-19 19:31   ` Andrew Morton
2020-02-19 19:31     ` Andrew Morton
2020-02-19 21:33     ` Johannes Weiner
2020-02-26 20:25 ` Shakeel Butt
2020-02-26 20:25   ` Shakeel Butt
2020-02-26 20:25   ` Shakeel Butt
2020-02-26 22:26   ` Johannes Weiner
2020-02-26 22:26     ` Johannes Weiner
2020-02-26 23:36     ` Shakeel Butt
2020-02-26 23:36       ` Shakeel Butt
2020-02-26 23:36       ` Shakeel Butt
2020-02-26 23:46       ` Johannes Weiner
2020-02-27  0:12     ` Yang Shi
2020-02-27  0:12       ` Yang Shi
2020-02-27  2:42       ` Shakeel Butt
2020-02-27  2:42         ` Shakeel Butt
2020-02-27  2:42         ` Shakeel Butt
2020-02-27  9:58       ` Michal Hocko
2020-02-27  9:58         ` Michal Hocko
2020-02-27 12:50       ` Johannes Weiner
2020-02-27 12:50         ` Johannes Weiner
2020-02-26 23:59   ` Yang Shi
2020-02-26 23:59     ` Yang Shi
2020-02-27  2:36     ` Shakeel Butt
2020-02-27  2:36       ` Shakeel Butt

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