From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with ESMTP id AB7B46B0169 for ; Wed, 3 Aug 2011 10:35:34 -0400 (EDT) Date: Wed, 3 Aug 2011 15:35:27 +0100 From: Mel Gorman Subject: Re: [PATCH 3/8] ext4: Warn if direct reclaim tries to writeback pages Message-ID: <20110803143527.GM19099@suse.de> References: <1311265730-5324-1-git-send-email-mgorman@suse.de> <1311265730-5324-4-git-send-email-mgorman@suse.de> <20110803105819.GA27199@redhat.com> <20110803110629.GB27199@redhat.com> <20110803134420.GH19099@suse.de> <20110803140019.GA31026@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20110803140019.GA31026@redhat.com> Sender: owner-linux-mm@kvack.org List-ID: To: Johannes Weiner Cc: Linux-MM , LKML , XFS , Dave Chinner , Christoph Hellwig , Wu Fengguang , Jan Kara , Rik van Riel , Minchan Kim On Wed, Aug 03, 2011 at 04:00:19PM +0200, Johannes Weiner wrote: > On Wed, Aug 03, 2011 at 02:44:20PM +0100, Mel Gorman wrote: > > On Wed, Aug 03, 2011 at 01:06:29PM +0200, Johannes Weiner wrote: > > > On Wed, Aug 03, 2011 at 12:58:19PM +0200, Johannes Weiner wrote: > > > > On Thu, Jul 21, 2011 at 05:28:45PM +0100, Mel Gorman wrote: > > > > > Direct reclaim should never writeback pages. Warn if an attempt > > > > > is made. > > > > > > > > > > Signed-off-by: Mel Gorman > > > > > > > > Acked-by: Johannes Weiner > > > > > > Oops, too fast. > > > > > > Shouldn't the WARN_ON() be at the top of the function, rather than > > > just warn when the write is deferred due to delalloc? > > > > I thought it made more sense to put the warning at the point where ext4 > > would normally ignore ->writepage. > > > > That said, in my current revision of the series, I've dropped these > > patches altogether as page migration should be able to trigger the same > > warnings but be called from paths that are of less concern for stack > > overflows (or at the very least be looked at as a separate series). > > Doesn't this only apply to btrfs which has no own .migratepage aop for > file pages? The others use buffer_migrate_page. > Bah, you're right. It was btrfs I was looking at during the time I decided to drop the patches and I didn't think it through. I only needed to drop the btrfs one. > But if you dropped them anyway, it does not matter :) I put back in the xfs and ext4 checks. The ext4 check is still in the same place. -- Mel Gorman SUSE Labs -- 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