From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with SMTP id C9A566B0169 for ; Wed, 3 Aug 2011 10:00:36 -0400 (EDT) Date: Wed, 3 Aug 2011 16:00:19 +0200 From: Johannes Weiner Subject: Re: [PATCH 3/8] ext4: Warn if direct reclaim tries to writeback pages Message-ID: <20110803140019.GA31026@redhat.com> 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110803134420.GH19099@suse.de> Sender: owner-linux-mm@kvack.org List-ID: To: Mel Gorman Cc: Linux-MM , LKML , XFS , Dave Chinner , Christoph Hellwig , Wu Fengguang , Jan Kara , Rik van Riel , Minchan Kim 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. But if you dropped them anyway, it does not matter :) -- 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