From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932227Ab0FOOi3 (ORCPT ); Tue, 15 Jun 2010 10:38:29 -0400 Received: from mx1.redhat.com ([209.132.183.28]:48093 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757869Ab0FOOi1 (ORCPT ); Tue, 15 Jun 2010 10:38:27 -0400 Message-ID: <4C1787DF.3020102@redhat.com> Date: Tue, 15 Jun 2010 10:02:07 -0400 From: Rik van Riel User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100430 Fedora/3.0.4-2.fc12 Lightning/1.0b2pre Thunderbird/3.0.4 MIME-Version: 1.0 To: Christoph Hellwig CC: Mel Gorman , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Dave Chinner , Chris Mason , Nick Piggin , Johannes Weiner , KAMEZAWA Hiroyuki , Andrew Morton Subject: Re: [PATCH 12/12] vmscan: Do not writeback pages in direct reclaim References: <1276514273-27693-1-git-send-email-mel@csn.ul.ie> <1276514273-27693-13-git-send-email-mel@csn.ul.ie> <4C16A567.4080000@redhat.com> <20100615114510.GE26788@csn.ul.ie> <4C17815A.8080402@redhat.com> <20100615133727.GA27980@infradead.org> In-Reply-To: <20100615133727.GA27980@infradead.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/15/2010 09:37 AM, Christoph Hellwig wrote: > On Tue, Jun 15, 2010 at 09:34:18AM -0400, Rik van Riel wrote: >> If direct reclaim can overflow the stack, so can direct >> memcg reclaim. That means this patch does not solve the >> stack overflow, while admitting that we do need the >> ability to get specific pages flushed to disk from the >> pageout code. > > Can you explain what the hell memcg reclaim is and why it needs > to reclaim from random contexts? The page fault code will call the cgroup accounting code. When a cgroup goes over its memory limit, __mem_cgroup_try_charge will call mem_cgroup_hierarchical_reclaim, which will then go into the page reclaim code. > It seems everything that has a cg in it's name that I stumbled over > lately seems to be some ugly wart.. No argument there. It took me a few minutes to find the code path above :) -- All rights reversed From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rik van Riel Subject: Re: [PATCH 12/12] vmscan: Do not writeback pages in direct reclaim Date: Tue, 15 Jun 2010 10:02:07 -0400 Message-ID: <4C1787DF.3020102@redhat.com> References: <1276514273-27693-1-git-send-email-mel@csn.ul.ie> <1276514273-27693-13-git-send-email-mel@csn.ul.ie> <4C16A567.4080000@redhat.com> <20100615114510.GE26788@csn.ul.ie> <4C17815A.8080402@redhat.com> <20100615133727.GA27980@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: Mel Gorman , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Dave Chinner , Chris Mason , Nick Piggin , Johannes Weiner , KAMEZAWA Hiroyuki , Andrew Morton To: Christoph Hellwig Return-path: In-Reply-To: <20100615133727.GA27980@infradead.org> Sender: owner-linux-mm@kvack.org List-Id: linux-fsdevel.vger.kernel.org On 06/15/2010 09:37 AM, Christoph Hellwig wrote: > On Tue, Jun 15, 2010 at 09:34:18AM -0400, Rik van Riel wrote: >> If direct reclaim can overflow the stack, so can direct >> memcg reclaim. That means this patch does not solve the >> stack overflow, while admitting that we do need the >> ability to get specific pages flushed to disk from the >> pageout code. > > Can you explain what the hell memcg reclaim is and why it needs > to reclaim from random contexts? The page fault code will call the cgroup accounting code. When a cgroup goes over its memory limit, __mem_cgroup_try_charge will call mem_cgroup_hierarchical_reclaim, which will then go into the page reclaim code. > It seems everything that has a cg in it's name that I stumbled over > lately seems to be some ugly wart.. No argument there. It took me a few minutes to find the code path above :) -- All rights reversed -- 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/ . Don't email: email@kvack.org