From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933493AbcFQSSw (ORCPT ); Fri, 17 Jun 2016 14:18:52 -0400 Received: from mail-yw0-f193.google.com ([209.85.161.193]:34858 "EHLO mail-yw0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933136AbcFQSSq (ORCPT ); Fri, 17 Jun 2016 14:18:46 -0400 Date: Fri, 17 Jun 2016 14:18:42 -0400 From: Tejun Heo To: Johannes Weiner Cc: Andrew Morton , Vladimir Davydov , Michal Hocko , Li Zefan , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com Subject: Re: [PATCH 3/3] mm: memcontrol: fix cgroup creation failure after many small jobs Message-ID: <20160617181842.GP3262@mtj.duckdns.org> References: <20160616034244.14839-1-hannes@cmpxchg.org> <20160616200617.GD3262@mtj.duckdns.org> <20160617162310.GA19084@cmpxchg.org> <20160617162516.GD19084@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160617162516.GD19084@cmpxchg.org> User-Agent: Mutt/1.6.1 (2016-04-27) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 Thanks. -- tejun