From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with ESMTP id 397B26B004A for ; Thu, 21 Jul 2011 19:51:44 -0400 (EDT) Received: from m4.gw.fujitsu.co.jp (unknown [10.0.50.74]) by fgwmail6.fujitsu.co.jp (Postfix) with ESMTP id 87B673EE0BB for ; Fri, 22 Jul 2011 08:51:40 +0900 (JST) Received: from smail (m4 [127.0.0.1]) by outgoing.m4.gw.fujitsu.co.jp (Postfix) with ESMTP id 6C78A45DE53 for ; Fri, 22 Jul 2011 08:51:40 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (s4.gw.fujitsu.co.jp [10.0.50.94]) by m4.gw.fujitsu.co.jp (Postfix) with ESMTP id 528D945DE4E for ; Fri, 22 Jul 2011 08:51:40 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id 43E8C1DB8043 for ; Fri, 22 Jul 2011 08:51:40 +0900 (JST) Received: from m106.s.css.fujitsu.com (m106.s.css.fujitsu.com [10.240.81.146]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id 0D39E1DB8037 for ; Fri, 22 Jul 2011 08:51:40 +0900 (JST) Date: Fri, 22 Jul 2011 08:44:13 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [PATCH 1/4] memcg: do not try to drain per-cpu caches without pages Message-Id: <20110722084413.9dd4b880.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20110721113606.GA27855@tiehlicka.suse.cz> References: <113c4affc2f0938b7b22d43c88d2b0a623de9a6b.1311241300.git.mhocko@suse.cz> <20110721191250.1c945740.kamezawa.hiroyu@jp.fujitsu.com> <20110721113606.GA27855@tiehlicka.suse.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: linux-mm@kvack.org, Balbir Singh , Daisuke Nishimura , linux-kernel@vger.kernel.org On Thu, 21 Jul 2011 13:36:06 +0200 Michal Hocko wrote: > On Thu 21-07-11 19:12:50, KAMEZAWA Hiroyuki wrote: > > On Thu, 21 Jul 2011 09:38:00 +0200 > > Michal Hocko wrote: > > > > > drain_all_stock_async tries to optimize a work to be done on the work > > > queue by excluding any work for the current CPU because it assumes that > > > the context we are called from already tried to charge from that cache > > > and it's failed so it must be empty already. > > > While the assumption is correct we can do it by checking the current > > > number of pages in the cache. This will also reduce a work on other CPUs > > > with an empty stock. > > > > > > Signed-off-by: Michal Hocko > > > > > > At the first look, when a charge against TransParentHugepage() goes > > into the reclaim routine, stock->nr_pages != 0 and this will > > call additional kworker. > > True. We will drain a charge which could be used by other allocations > in the meantime so we have a good chance to reclaim less. But how big > problem is that? > I mean I can add a new parameter that would force checking the current > cpu but it doesn't look nice. I cannot add that condition > unconditionally because the code will be shared with the sync path in > the next patch and that one needs to drain _all_ cpus. > > What would you suggest? By 2 methods - just check nr_pages. - drain "local stock" without calling schedule_work(). It's fast. Thanks, -Kame -- 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