From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail6.bemta7.messagelabs.com (mail6.bemta7.messagelabs.com [216.82.255.55]) by kanga.kvack.org (Postfix) with ESMTP id 5D8F56B007B for ; Fri, 3 Jun 2011 01:08:31 -0400 (EDT) Received: from kpbe12.cbf.corp.google.com (kpbe12.cbf.corp.google.com [172.25.105.76]) by smtp-out.google.com with ESMTP id p5358NSc011660 for ; Thu, 2 Jun 2011 22:08:28 -0700 Received: from qyk7 (qyk7.prod.google.com [10.241.83.135]) by kpbe12.cbf.corp.google.com with ESMTP id p5358LaV001233 (version=TLSv1/SSLv3 cipher=RC4-SHA bits=128 verify=NOT) for ; Thu, 2 Jun 2011 22:08:22 -0700 Received: by qyk7 with SMTP id 7so3009287qyk.12 for ; Thu, 02 Jun 2011 22:08:21 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20110602221906.GA4554@cmpxchg.org> References: <1306909519-7286-1-git-send-email-hannes@cmpxchg.org> <1306909519-7286-8-git-send-email-hannes@cmpxchg.org> <20110602221906.GA4554@cmpxchg.org> Date: Thu, 2 Jun 2011 22:08:21 -0700 Message-ID: Subject: Re: [patch 7/8] vmscan: memcg-aware unevictable page rescue scanner From: Ying Han Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org List-ID: To: Johannes Weiner Cc: Hiroyuki Kamezawa , KAMEZAWA Hiroyuki , Daisuke Nishimura , Balbir Singh , Michal Hocko , Andrew Morton , Rik van Riel , Minchan Kim , KOSAKI Motohiro , Mel Gorman , Greg Thelen , Michel Lespinasse , "linux-mm@kvack.org" , linux-kernel On Thu, Jun 2, 2011 at 3:19 PM, Johannes Weiner wrote: > On Fri, Jun 03, 2011 at 07:01:34AM +0900, Hiroyuki Kamezawa wrote: >> 2011/6/3 Ying Han : >> > On Thu, Jun 2, 2011 at 6:27 AM, Hiroyuki Kamezawa >> > wrote: >> >> 2011/6/1 Johannes Weiner : >> >>> Once the per-memcg lru lists are exclusive, the unevictable page >> >>> rescue scanner can no longer work on the global zone lru lists. >> >>> >> >>> This converts it to go through all memcgs and scan their respective >> >>> unevictable lists instead. >> >>> >> >>> Signed-off-by: Johannes Weiner >> >> >> >> Hm, isn't it better to have only one GLOBAL LRU for unevictable pages= ? >> >> memcg only needs counter for unevictable pages and LRU is not necessa= ry >> >> to be per memcg because we don't reclaim it... >> > >> > Hmm. Are we suggesting to keep one un-evictable LRU list for all >> > memcgs? So we will have >> > exclusive lru only for file and anon. If so, we are not done to make >> > all the lru list being exclusive >> > which is critical later to improve the zone->lru_lock contention >> > across the memcgs >> > >> considering lrulock, yes, maybe you're right. > > That's one of the complications. That should be achievable if we make all the per-memcg lru being exclusive. So we can switch the global zone->lru_lock to per-memcg-per-zone lru_lock. We have a prototype of the patch doing something like that, but we will wait for this effort being discussed and reviewed. --Ying > >> > Sorry If i misinterpret the suggestion here >> > >> >> My concern is I don't know for what purpose this function is used .. > > I am not sure how it's supposed to be used, either. =A0But it's > documented to be a 'really big hammer' and it's kicked off from > userspace. =A0So I suppose having the thing go through all memcgs bears > a low risk of being a problem. =A0My suggestion is we go that way until > someone complains. > -- 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