Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759508Ab0GVPew (ORCPT ); Thu, 22 Jul 2010 11:34:52 -0400 Received: from mail-pw0-f46.google.com ([209.85.160.46]:40926 "EHLO mail-pw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754762Ab0GVPeu (ORCPT ); Thu, 22 Jul 2010 11:34:50 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=Vy841abBgFhZzCse4DuIISlHq0gnC2VafrSWO7q8Kfm1oG898Y/sPuXz7lgSg9vxVZ rG0YuZQ1d5MoOv+uKzU4cgq9c58oGrMAQ8wkeEZa7EpCB7BzNPY4DWTuikAA/JDsyYuV 0YDuMJy5+E7jhmFZmETx7389C0wnV6Bhu2mfI= Date: Fri, 23 Jul 2010 00:34:40 +0900 From: Minchan Kim To: Wu Fengguang Cc: Mel Gorman , Christoph Hellwig , "linux-kernel@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , "linux-mm@kvack.org" , Dave Chinner , Chris Mason , Nick Piggin , Rik van Riel , Johannes Weiner , KAMEZAWA Hiroyuki , KOSAKI Motohiro , Andrew Morton , Andrea Arcangeli Subject: Re: [PATCH 7/8] writeback: sync old inodes first in background writeback Message-ID: <20100722153440.GA1898@barrios-desktop> References: <1279545090-19169-1-git-send-email-mel@csn.ul.ie> <1279545090-19169-8-git-send-email-mel@csn.ul.ie> <20100719142145.GD12510@infradead.org> <20100719144046.GR13117@csn.ul.ie> <20100722085210.GA26714@localhost> <20100722092155.GA28425@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100722092155.GA28425@localhost> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2183 Lines: 64 Hi, Wu. Thanks for Cced me. AFAIR, we discussed this by private mail and didn't conclude yet. Let's start from beginning. On Thu, Jul 22, 2010 at 05:21:55PM +0800, Wu Fengguang wrote: > > I guess this new patch is more problem oriented and acceptable: > > > > --- linux-next.orig/mm/vmscan.c 2010-07-22 16:36:58.000000000 +0800 > > +++ linux-next/mm/vmscan.c 2010-07-22 16:39:57.000000000 +0800 > > @@ -1217,7 +1217,8 @@ static unsigned long shrink_inactive_lis > > count_vm_events(PGDEACTIVATE, nr_active); > > > > nr_freed += shrink_page_list(&page_list, sc, > > - PAGEOUT_IO_SYNC); > > + priority < DEF_PRIORITY / 3 ? > > + PAGEOUT_IO_SYNC : PAGEOUT_IO_ASYNC); > > } > > > > nr_reclaimed += nr_freed; > > This one looks better: > --- > vmscan: raise the bar to PAGEOUT_IO_SYNC stalls > > Fix "system goes totally unresponsive with many dirty/writeback pages" > problem: > > http://lkml.org/lkml/2010/4/4/86 > > The root cause is, wait_on_page_writeback() is called too early in the > direct reclaim path, which blocks many random/unrelated processes when > some slow (USB stick) writeback is on the way. > > A simple dd can easily create a big range of dirty pages in the LRU > list. Therefore priority can easily go below (DEF_PRIORITY - 2) in a > typical desktop, which triggers the lumpy reclaim mode and hence > wait_on_page_writeback(). I see oom message. order is zero. How is lumpy reclaim work? For working lumpy reclaim, we have to meet priority < 10 and sc->order > 0. Please, clarify the problem. > > In Andreas' case, 512MB/1024 = 512KB, this is way too low comparing to > the 22MB writeback and 190MB dirty pages. There can easily be a What's 22MB and 190M? It would be better to explain more detail. I think the description has to be clear as summary of the problem without the above link. Thanks for taking out this problem, again. :) -- Kind regards, Minchan Kim -- 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/