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From: Tejun Heo <tj@kernel.org>
To: Michal Hocko <mhocko@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>,
	Jakub Kicinski <kuba@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linux MM <linux-mm@kvack.org>, Kernel Team <kernel-team@fb.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Chris Down <chris@chrisdown.name>,
	Cgroups <cgroups@vger.kernel.org>
Subject: Re: [PATCH 0/3] memcg: Slow down swap allocation as the available space gets depleted
Date: Mon, 20 Apr 2020 13:06:50 -0400	[thread overview]
Message-ID: <20200420170650.GA169746@mtj.thefacebook.com> (raw)
In-Reply-To: <20200420170318.GV27314@dhcp22.suse.cz>

Hello,

On Mon, Apr 20, 2020 at 07:03:18PM +0200, Michal Hocko wrote:
> I have asked about the semantic of this know already and didn't really
> get any real answer. So how does swap.high fit into high limit semantic
> when it doesn't act as a limit. Considering that we cannot reclaim swap
> space I find this really hard to grasp.

memory.high slow down is for the case when memory reclaim can't be depended
upon for throttling, right? This is the same. Swap can't be reclaimed so the
backpressure is applied by slowing down the source, the same way memory.high
does.

It fits together with memory.low in that it prevents runaway anon allocation
when swap can't be allocated anymore. It's addressing the same problem that
memory.high slowdown does. It's just a different vector.

Thanks.

-- 
tejun


  reply	other threads:[~2020-04-20 17:06 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-17  1:06 [PATCH 0/3] memcg: Slow down swap allocation as the available space gets depleted Jakub Kicinski
2020-04-17  1:06 ` [PATCH 1/3] mm: prepare for swap over-high accounting and penalty calculation Jakub Kicinski
2020-04-17  1:06 ` [PATCH 2/3] mm: move penalty delay clamping out of calculate_high_delay() Jakub Kicinski
2020-04-17  1:06 ` [PATCH 3/3] mm: automatically penalize tasks with high swap use Jakub Kicinski
2020-04-17  7:37   ` Michal Hocko
2020-04-17 23:22     ` Jakub Kicinski
2020-04-17 16:11 ` [PATCH 0/3] memcg: Slow down swap allocation as the available space gets depleted Shakeel Butt
2020-04-17 16:23   ` Tejun Heo
2020-04-17 17:18     ` Shakeel Butt
2020-04-17 17:36       ` Tejun Heo
2020-04-17 17:51         ` Shakeel Butt
2020-04-17 19:35           ` Tejun Heo
2020-04-17 21:51             ` Shakeel Butt
2020-04-17 22:59               ` Tejun Heo
2020-04-20 16:12                 ` Shakeel Butt
2020-04-20 16:47                   ` Tejun Heo
2020-04-20 17:03                     ` Michal Hocko
2020-04-20 17:06                       ` Tejun Heo [this message]
2020-04-21 11:06                         ` Michal Hocko
2020-04-21 14:27                           ` Johannes Weiner
2020-04-21 16:11                             ` Michal Hocko
2020-04-21 16:56                               ` Johannes Weiner
2020-04-22 13:26                                 ` Michal Hocko
2020-04-22 14:15                                   ` Johannes Weiner
2020-04-22 15:43                                     ` Michal Hocko
2020-04-22 17:13                                       ` Johannes Weiner
2020-04-22 18:49                                         ` Michal Hocko
2020-04-23 15:00                                           ` Johannes Weiner
2020-04-24 15:05                                             ` Michal Hocko
2020-04-28 14:24                                               ` Johannes Weiner
2020-04-29  9:55                                                 ` Michal Hocko
2020-04-21 19:09                             ` Shakeel Butt
2020-04-21 21:59                               ` Johannes Weiner
2020-04-21 22:39                                 ` Shakeel Butt
2020-04-21 15:20                           ` Tejun Heo

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