From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752513AbcFUPst (ORCPT ); Tue, 21 Jun 2016 11:48:49 -0400 Received: from gum.cmpxchg.org ([85.214.110.215]:60794 "EHLO gum.cmpxchg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752148AbcFUPsq (ORCPT ); Tue, 21 Jun 2016 11:48:46 -0400 Date: Tue, 21 Jun 2016 11:46:01 -0400 From: Johannes Weiner To: Vladimir Davydov Cc: Tejun Heo , Andrew Morton , 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: <20160621154601.GA22431@cmpxchg.org> References: <20160616034244.14839-1-hannes@cmpxchg.org> <20160616200617.GD3262@mtj.duckdns.org> <20160617162310.GA19084@cmpxchg.org> <20160617162516.GD19084@cmpxchg.org> <20160621101650.GD15970@esperanza> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160621101650.GD15970@esperanza> 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 Tue, Jun 21, 2016 at 01:16:51PM +0300, Vladimir Davydov wrote: > On Fri, Jun 17, 2016 at 12:25:16PM -0400, Johannes Weiner wrote: > > After this patch, the IDs get released upon cgroup destruction and the > > cache and css objects get released once memory reclaim kicks in. > > With 65K cgroups it will take the reclaimer a substantial amount of time > to iterate over all of them, which might result in latency spikes. > Probably, to avoid that, we could move pages from a dead cgroup's lru to > its parent's one on offline while still leaving dead cgroups pinned, > like we do in case of list_lru entries. Yep, that is true. list_lru is a bit easier because the walker stays in the context of the original LRU list, whereas the cache/anon LRUs are not. We'd have to have mem_cgroup_page_lruvec() etc. do a parent walk to find the closest live ancestor. Maybe you have a better idea? But it's definitely worth considering. I'll think more about it. > > Signed-off-by: Johannes Weiner > > Reviewed-by: Vladimir Davydov Thanks! > > +static struct idr mem_cgroup_idr; > > static DEFINE_IDR(mem_cgroup_idr); Oops, good catch. Andrew, could you kindly fold this? >>From d1261ede8f975a5fccb2e9125562260e4b4b4f3d Mon Sep 17 00:00:00 2001 From: Johannes Weiner Date: Tue, 21 Jun 2016 11:36:13 -0400 Subject: [PATCH] mm: memcontrol: fix cgroup creation failure after many small jobs fix init the IDR Reported-by: Vladimir Davydov Signed-off-by: Johannes Weiner --- mm/memcontrol.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index dc92b2df2585..b0de1342eab2 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -4081,7 +4081,7 @@ static struct cftype mem_cgroup_legacy_files[] = { * those references are manageable from userspace. */ -static struct idr mem_cgroup_idr; +static DEFINE_IDR(mem_cgroup_idr); static void mem_cgroup_id_get(struct mem_cgroup *memcg) { -- 2.8.3