Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752013Ab1FCFI3 (ORCPT ); Fri, 3 Jun 2011 01:08:29 -0400 Received: from smtp-out.google.com ([74.125.121.67]:24145 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750890Ab1FCFI1 convert rfc822-to-8bit (ORCPT ); Fri, 3 Jun 2011 01:08:27 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=google.com; s=beta; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=QmqHjEScmRo3X16TnvEpQysS8dELVlGq05IbKsjux1gKKVCq8cZBa5sRIGOO3o++R3 Zc9igfNs6Wvl036te7vg== 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 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 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2237 Lines: 54 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 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. 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. ?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 from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/