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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 15:54:16 -0500	[thread overview]
Message-ID: <20200220205416.GI698990@mtj.thefacebook.com> (raw)
In-Reply-To: <20200220195535.7xblt45akld6eftj-S51bK0XF4qpuJJETbFA3a0B3C2bhBk7L0E9HWUfgJXw@public.gmane.org>

Hello, Daniel.

On Thu, Feb 20, 2020 at 02:55:35PM -0500, Daniel Jordan wrote:
> On Thu, Feb 20, 2020 at 01:45:45PM -0500, Tejun Heo wrote:
> > 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.
> 
> I see, your last mail is clearer now.  If it's easy to do, a pointer to where
> this happens would help so we're on the same page.

Network packet rx is the clearest example I think, but you already
mentioned it. Reclaim is less so but when kswapd reclaims, it walks
everybody, and there can be a lot of small cgroups.

Thanks.

-- 
tejun

  parent reply	other threads:[~2020-02-20 20:54 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-19 18:12 [PATCH] mm: memcontrol: asynchronous reclaim for memory.high Johannes Weiner
     [not found] ` <20200219181219.54356-1-hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>
2020-02-19 18:37   ` Michal Hocko
     [not found]     ` <20200219183731.GC11847-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2020-02-19 19:16       ` Johannes Weiner
     [not found]         ` <20200219191618.GB54486-druUgvl0LCNAfugRpC6u6w@public.gmane.org>
2020-02-19 19:53           ` Michal Hocko
2020-02-19 21:17             ` Johannes Weiner
     [not found]               ` <20200219211735.GD54486-druUgvl0LCNAfugRpC6u6w@public.gmane.org>
2020-02-20  9:46                 ` Michal Hocko
     [not found]                   ` <20200220094639.GD20509-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2020-02-20 14:41                     ` Johannes Weiner
     [not found]             ` <20200219195332.GE11847-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2020-02-19 21:41               ` Daniel Jordan
     [not found]                 ` <20200219214112.4kt573kyzbvmbvn3-S51bK0XF4qpuJJETbFA3a0B3C2bhBk7L0E9HWUfgJXw@public.gmane.org>
2020-02-19 22:08                   ` Johannes Weiner
     [not found]                     ` <20200219220859.GF54486-druUgvl0LCNAfugRpC6u6w@public.gmane.org>
2020-02-20 15:45                       ` Daniel Jordan
     [not found]                         ` <20200220154524.dql3i5brnjjwecft-S51bK0XF4qpuJJETbFA3a0B3C2bhBk7L0E9HWUfgJXw@public.gmane.org>
2020-02-20 15:56                           ` Tejun Heo
     [not found]                             ` <20200220155651.GG698990-146+VewaZzwNjtGbbfXrCEEOCMrvLtNR@public.gmane.org>
2020-02-20 18:23                               ` Daniel Jordan
     [not found]                                 ` <20200220182326.ubcjycaubgykiy6e-S51bK0XF4qpuJJETbFA3a0B3C2bhBk7L0E9HWUfgJXw@public.gmane.org>
2020-02-20 18:45                                   ` Tejun Heo
     [not found]                                     ` <20200220184545.GH698990-146+VewaZzwNjtGbbfXrCEEOCMrvLtNR@public.gmane.org>
2020-02-20 19:55                                       ` Daniel Jordan
     [not found]                                         ` <20200220195535.7xblt45akld6eftj-S51bK0XF4qpuJJETbFA3a0B3C2bhBk7L0E9HWUfgJXw@public.gmane.org>
2020-02-20 20:54                                           ` Tejun Heo [this message]
2020-02-19 19:17       ` Chris Down
2020-02-19 19:31       ` Andrew Morton
2020-02-19 21:33         ` Johannes Weiner
2020-02-26 20:25   ` Shakeel Butt
     [not found]     ` <CALvZod7fya+o8mO+qo=FXjk3WgNje=2P=sxM5StgdBoGNeXRMg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2020-02-26 22:26       ` Johannes Weiner
     [not found]         ` <20200226222642.GB30206-druUgvl0LCNAfugRpC6u6w@public.gmane.org>
2020-02-26 23:36           ` Shakeel Butt
2020-02-26 23:46             ` Johannes Weiner
2020-02-27  0:12           ` Yang Shi
     [not found]             ` <2be6ac8d-e290-0a85-5cfa-084968a7fe36-KPsoFbNs7GizrGE5bRqYAgC/G2K4zDHf@public.gmane.org>
2020-02-27  2:42               ` Shakeel Butt
2020-02-27  9:58               ` Michal Hocko
2020-02-27 12:50               ` Johannes Weiner
2020-02-26 23:59       ` Yang Shi
2020-02-27  2:36         ` Shakeel Butt

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