Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751503AbZJPWcc (ORCPT ); Fri, 16 Oct 2009 18:32:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751011AbZJPWcc (ORCPT ); Fri, 16 Oct 2009 18:32:32 -0400 Received: from gir.skynet.ie ([193.1.99.77]:35941 "EHLO gir.skynet.ie" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750911AbZJPWcb (ORCPT ); Fri, 16 Oct 2009 18:32:31 -0400 Date: Fri, 16 Oct 2009 23:32:37 +0100 From: Mel Gorman To: David Rientjes Cc: Andrew Morton , stable , "Rafael J. Wysocki" , David Miller , Frans Pop , reinette chatre , Kalle Valo , "John W. Linville" , Pekka Enberg , Bartlomiej Zolnierkiewicz , Karol Lewandowski , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, "linux-mm@kvack.org" Subject: Re: [PATCH 2/2] page allocator: Direct reclaim should always obey watermarks Message-ID: <20091016223237.GE32397@csn.ul.ie> References: <1255689446-3858-1-git-send-email-mel@csn.ul.ie> <1255689446-3858-3-git-send-email-mel@csn.ul.ie> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17+20080114 (2008-01-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1893 Lines: 47 On Fri, Oct 16, 2009 at 12:07:07PM -0700, David Rientjes wrote: > On Fri, 16 Oct 2009, Mel Gorman wrote: > > > ALLOC_NO_WATERMARKS should be cleared when trying to allocate from the > > free-lists after a direct reclaim. If it's not, __GFP_NOFAIL allocations > > from a process that is exiting can ignore watermarks. __GFP_NOFAIL is not > > often used but the journal layer is one of those places. This is suspected of > > causing an increase in the number of GFP_ATOMIC allocation failures reported. > > > > Signed-off-by: Mel Gorman > > --- > > mm/page_alloc.c | 3 ++- > > 1 files changed, 2 insertions(+), 1 deletions(-) > > > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > > index dfa4362..a3e5fed 100644 > > --- a/mm/page_alloc.c > > +++ b/mm/page_alloc.c > > @@ -1860,7 +1860,8 @@ rebalance: > > page = __alloc_pages_direct_reclaim(gfp_mask, order, > > zonelist, high_zoneidx, > > nodemask, > > - alloc_flags, preferred_zone, > > + alloc_flags & ~ALLOC_NO_WATERMARKS, > > + preferred_zone, > > migratetype, &did_some_progress); > > if (page) > > goto got_pg; > > I don't get it. __alloc_pages_high_priority() will already loop > indefinitely if ALLOC_NO_WATERMARKS is set and its a __GFP_NOFAIL > allocation. How do we even reach this code in such a condition? > Frans, you reported that both patches in combination reduced the number of failures. Was it in fact just the kswapd change that made the difference? -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- 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/