From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with ESMTP id 5B2976B004A for ; Thu, 2 Jun 2011 18:19:32 -0400 (EDT) Date: Fri, 3 Jun 2011 00:19:06 +0200 From: Johannes Weiner Subject: Re: [patch 7/8] vmscan: memcg-aware unevictable page rescue scanner Message-ID: <20110602221906.GA4554@cmpxchg.org> References: <1306909519-7286-1-git-send-email-hannes@cmpxchg.org> <1306909519-7286-8-git-send-email-hannes@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Hiroyuki Kamezawa Cc: Ying Han , 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 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 necessary > >> 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. > > 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. But it's documented to be a 'really big hammer' and it's kicked off from userspace. So I suppose having the thing go through all memcgs bears a low risk of being a problem. My 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