From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx156.postini.com [74.125.245.156]) by kanga.kvack.org (Postfix) with SMTP id 912186B0044 for ; Wed, 7 Nov 2012 02:05:23 -0500 (EST) Message-ID: <509A0826.1030708@parallels.com> Date: Wed, 7 Nov 2012 08:05:10 +0100 From: Glauber Costa MIME-Version: 1.0 Subject: Re: [PATCH v6 18/29] Allocate memory for memcg caches whenever a new memcg appears References: <1351771665-11076-1-git-send-email-glommer@parallels.com> <1351771665-11076-19-git-send-email-glommer@parallels.com> <20121105162330.4aa629f8.akpm@linux-foundation.org> In-Reply-To: <20121105162330.4aa629f8.akpm@linux-foundation.org> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, kamezawa.hiroyu@jp.fujitsu.com, Johannes Weiner , Tejun Heo , Michal Hocko , Christoph Lameter , Pekka Enberg , David Rientjes , Pekka Enberg , Suleiman Souhlal On 11/06/2012 01:23 AM, Andrew Morton wrote: > On Thu, 1 Nov 2012 16:07:34 +0400 > Glauber Costa wrote: > >> Every cache that is considered a root cache (basically the "original" caches, >> tied to the root memcg/no-memcg) will have an array that should be large enough >> to store a cache pointer per each memcg in the system. >> >> Theoreticaly, this is as high as 1 << sizeof(css_id), which is currently in the >> 64k pointers range. Most of the time, we won't be using that much. >> >> What goes in this patch, is a simple scheme to dynamically allocate such an >> array, in order to minimize memory usage for memcg caches. Because we would >> also like to avoid allocations all the time, at least for now, the array will >> only grow. It will tend to be big enough to hold the maximum number of >> kmem-limited memcgs ever achieved. >> >> We'll allocate it to be a minimum of 64 kmem-limited memcgs. When we have more >> than that, we'll start doubling the size of this array every time the limit is >> reached. >> >> Because we are only considering kmem limited memcgs, a natural point for this >> to happen is when we write to the limit. At that point, we already have >> set_limit_mutex held, so that will become our natural synchronization >> mechanism. >> >> ... >> >> +static struct ida kmem_limited_groups; > > Could use DEFINE_IDA() here > >> >> ... >> >> static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss) >> { >> + int ret; >> + >> memcg->kmemcg_id = -1; >> - memcg_propagate_kmem(memcg); >> + ret = memcg_propagate_kmem(memcg); >> + if (ret) >> + return ret; >> + >> + if (mem_cgroup_is_root(memcg)) >> + ida_init(&kmem_limited_groups); > > and zap this? > Ok. I am starting to go over your replies now, and general question: Since you have already included this in mm, would you like me to resubmit the series changing things according to your feedback, or should I send incremental patches? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org