From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752848Ab1HCNpS (ORCPT ); Wed, 3 Aug 2011 09:45:18 -0400 Received: from cantor2.suse.de ([195.135.220.15]:35024 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751361Ab1HCNpL (ORCPT ); Wed, 3 Aug 2011 09:45:11 -0400 Date: Wed, 3 Aug 2011 14:45:07 +0100 From: Mel Gorman To: Johannes Weiner Cc: Linux-MM , LKML , XFS , Dave Chinner , Christoph Hellwig , Wu Fengguang , Jan Kara , Rik van Riel , Minchan Kim Subject: Re: [PATCH 4/8] btrfs: Warn if direct reclaim tries to writeback pages Message-ID: <20110803134507.GI19099@suse.de> References: <1311265730-5324-1-git-send-email-mgorman@suse.de> <1311265730-5324-5-git-send-email-mgorman@suse.de> <20110803111031.GC27199@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20110803111031.GC27199@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 03, 2011 at 01:10:31PM +0200, Johannes Weiner wrote: > On Thu, Jul 21, 2011 at 05:28:46PM +0100, Mel Gorman wrote: > > Direct reclaim should never writeback pages. Warn if an attempt is > > made. By rights, btrfs should be allowing writepage from kswapd if > > it is failing to reclaim pages by any other means but it's outside > > the scope of this patch. > > > > Signed-off-by: Mel Gorman > > --- > > fs/btrfs/disk-io.c | 2 ++ > > fs/btrfs/inode.c | 2 ++ > > 2 files changed, 4 insertions(+), 0 deletions(-) > > > > diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c > > index 1ac8db5d..cc9c9cf 100644 > > --- a/fs/btrfs/disk-io.c > > +++ b/fs/btrfs/disk-io.c > > @@ -829,6 +829,8 @@ static int btree_writepage(struct page *page, struct writeback_control *wbc) > > > > tree = &BTRFS_I(page->mapping->host)->io_tree; > > if (!(current->flags & PF_MEMALLOC)) { > > + WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD)) == > > + PF_MEMALLOC); > > Since it is branch for PF_MEMALLOC being set, why not just > WARN_ON_ONCE(!(current->flags & PF_KSWAPD)) instead? > > Minor nitpick, though, and I can understand if you just want to have > the conditionals be the same in every fs. > It was just copying the conditionals for the other FS although I admit your version would look nicer. -- Mel Gorman SUSE Labs