From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx149.postini.com [74.125.245.149]) by kanga.kvack.org (Postfix) with SMTP id 6E9276B0044 for ; Fri, 30 Mar 2012 09:53:24 -0400 (EDT) Message-ID: <4F75BACC.7050704@parallels.com> Date: Fri, 30 Mar 2012 15:53:16 +0200 From: Glauber Costa MIME-Version: 1.0 Subject: Re: [RFC 5/7] use percpu_counters for res_counter usage References: <1333094685-5507-1-git-send-email-glommer@parallels.com> <1333094685-5507-6-git-send-email-glommer@parallels.com> <4F757DEB.4030006@jp.fujitsu.com> <4F7583AB.3070304@jp.fujitsu.com> In-Reply-To: <4F7583AB.3070304@jp.fujitsu.com> Content-Type: text/plain; charset="ISO-2022-JP" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: KAMEZAWA Hiroyuki Cc: cgroups@vger.kernel.org, Li Zefan , Tejun Heo , devel@openvz.org, Johannes Weiner , Michal Hocko , Linux MM , Pavel Emelyanov On 03/30/2012 11:58 AM, KAMEZAWA Hiroyuki wrote: > == > > Now, we do consume 'reserved' usage, we can avoid css_get(), an heavy atomic > ops. You may need to move this code as > > rcu_read_lock() > .... > res_counter_charge() > if (failure) { > css_tryget() > rcu_read_unlock() > } else { > rcu_read_unlock() > return success; > } > > to compare performance. This css_get() affects performance very very much. thanks for the tip. But one thing: To be sure: it effectively mean that we are drawing from a dead memcg (because we pre-allocated, right? -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org