linux-kernel - Re: [PATCH 3/3] mm: memcontrol: fix cgroup creation failure after many small jobs

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Message-ID: <20160617181842.GP3262@mtj.duckdns.org>
Date:	Fri, 17 Jun 2016 14:18:42 -0400
From:	Tejun Heo <tj@...nel.org>
To:	Johannes Weiner <hannes@...xchg.org>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Vladimir Davydov <vdavydov@...tuozzo.com>,
	Michal Hocko <mhocko@...e.cz>, Li Zefan <lizefan@...wei.com>,
	linux-mm@...ck.org, cgroups@...r.kernel.org,
	linux-kernel@...r.kernel.org, kernel-team@...com
Subject: Re: [PATCH 3/3] mm: memcontrol: fix cgroup creation failure after
 many small jobs

On Fri, Jun 17, 2016 at 12:25:16PM -0400, Johannes Weiner wrote:
> The memory controller has quite a bit of state that usually outlives
> the cgroup and pins its CSS until said state disappears. At the same
> time it imposes a 16-bit limit on the CSS ID space to economically
> store IDs in the wild. Consequently, when we use cgroups to contain
> frequent but small and short-lived jobs that leave behind some page
> cache, we quickly run into the 64k limitations of outstanding CSSs.
> Creating a new cgroup fails with -ENOSPC while there are only a few,
> or even no user-visible cgroups in existence.

Acked-by: Tejun Heo <tj@...nel.org>

Thanks.

-- 
tejun