From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with ESMTP id E96D38D0039 for ; Wed, 9 Mar 2011 00:43:37 -0500 (EST) Received: from m2.gw.fujitsu.co.jp (unknown [10.0.50.72]) by fgwmail6.fujitsu.co.jp (Postfix) with ESMTP id 812463EE0BB for ; Wed, 9 Mar 2011 14:43:33 +0900 (JST) Received: from smail (m2 [127.0.0.1]) by outgoing.m2.gw.fujitsu.co.jp (Postfix) with ESMTP id 668AC45DE4E for ; Wed, 9 Mar 2011 14:43:33 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (s2.gw.fujitsu.co.jp [10.0.50.92]) by m2.gw.fujitsu.co.jp (Postfix) with ESMTP id 4637645DE6C for ; Wed, 9 Mar 2011 14:43:33 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id 2B4C01DB8040 for ; Wed, 9 Mar 2011 14:43:33 +0900 (JST) Received: from ml14.s.css.fujitsu.com (ml14.s.css.fujitsu.com [10.240.81.134]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id E0C5D1DB803A for ; Wed, 9 Mar 2011 14:43:32 +0900 (JST) Date: Wed, 9 Mar 2011 14:37:04 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [PATCH] mm: check zone->all_unreclaimable in all_unreclaimable() Message-Id: <20110309143704.194e8ee1.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: References: <1299325456-2687-1-git-send-email-avagin@openvz.org> <20110305152056.GA1918@barrios-desktop> <4D72580D.4000208@gmail.com> <20110305155316.GB1918@barrios-desktop> <4D7267B6.6020406@gmail.com> <20110305170759.GC1918@barrios-desktop> <20110307135831.9e0d7eaa.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: Minchan Kim Cc: Andrew Morton , Andrew Vagin , Andrey Vagin , Mel Gorman , KOSAKI Motohiro , linux-mm@kvack.org, linux-kernel@vger.kernel.org On Tue, 8 Mar 2011 08:45:51 +0900 Minchan Kim wrote: > On Tue, Mar 8, 2011 at 6:58 AM, Andrew Morton wrote: > > On Sun, 6 Mar 2011 02:07:59 +0900 > > Minchan Kim wrote: > > Any alternative proposals? A We should get the livelock fixed if possible.. > > > > And we should avoid unnecessary OOM kill if possible. > > I think the problem is caused by (zone->pages_scanned < > zone_reclaimable_pages(zone) * 6). I am not sure (* 6) is a best. It > would be rather big on recent big DRAM machines. > It means 3 times full-scan from the highest priority to the lowest and cannot freed any pages. I think big memory machine tend to have more cpus, so don't think it's big. > I think it is a trade-off between latency and OOM kill. > If we decrease the magic value, maybe we should prevent the almost > livelock but happens unnecessary OOM kill. > Hmm, should I support a sacrifice feature 'some signal(SIGINT?) will be sent by the kernel when it detects system memory is in short' in cgroup ? (For example, if full LRU scan is done in a zone, notifier works and SIGINT will be sent.) > And I think zone_reclaimable not fair. > For example, too many scanning makes reclaimable state to > unreclaimable state. Maybe it takes a very long time. But just some > page free makes unreclaimable state to reclaimabe with very easy. So > we need much painful reclaiming for changing reclaimable state with > unreclaimabe state. it would affect latency very much. > > Maybe we need more smart zone_reclaimabe which is adaptive with memory pressure. > I agree. 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