From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754680Ab0IBDFQ (ORCPT ); Wed, 1 Sep 2010 23:05:16 -0400 Received: from fgwmail7.fujitsu.co.jp ([192.51.44.37]:51503 "EHLO fgwmail7.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754357Ab0IBDFN (ORCPT ); Wed, 1 Sep 2010 23:05:13 -0400 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 From: KOSAKI Motohiro To: Minchan Kim Subject: Re: [BUGFIX][PATCH] vmscan: don't use return value trick when oom_killer_disabled Cc: kosaki.motohiro@jp.fujitsu.com, Johannes Weiner , Rik van Riel , "Rafael J. Wysocki" , "M. Vefa Bicakci" , LKML , linux-mm , Andrew Morton In-Reply-To: References: <20100902091206.D053.A69D9226@jp.fujitsu.com> Message-Id: <20100902115640.D071.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.50.07 [ja] Date: Thu, 2 Sep 2010 12:05:06 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > I don't want to send risky patch to -stable. > > Still I don't want to use oom_killer_disabled magic. > But I don't want to prevent urgent stable patch due to my just nitpick. > > This is my last try(just quick patch, even I didn't tried compile test). Looks like conceptually correct. If you will test it and fix whitespace damage, I'll ack this one gladly. Thanks. > If this isn't good, first of all, let's try merge yours. > And then we can fix it later. > > Thanks for comment. > > -- CUT HERE -- > > Why do we check zone->all_unreclaimable in only kswapd? > If kswapd is freezed in hibernation, OOM can happen. > Let's the check in direct reclaim path, too. > > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index 3109ff7..41493ba 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -1878,12 +1878,11 @@ static void shrink_zone(int priority, struct zone *zone, > * If a zone is deemed to be full of pinned pages then just give it a light > * scan then give up on it. > */ > -static bool shrink_zones(int priority, struct zonelist *zonelist, > +static void shrink_zones(int priority, struct zonelist *zonelist, > struct scan_control *sc) > { > struct zoneref *z; > struct zone *zone; > - bool all_unreclaimable = true; > > for_each_zone_zonelist_nodemask(zone, z, zonelist, > gfp_zone(sc->gfp_mask), sc->nodemask) { > @@ -1901,8 +1900,25 @@ static bool shrink_zones(int priority, struct > zonelist *zonelist, > } > > shrink_zone(priority, zone, sc); > - all_unreclaimable = false; > } > +} > + > +static inline int all_unreclaimable(struct zonelist *zonelist, struct > scan_control *sc) > +{ > + struct zoneref *z; > + struct zone *zone; > + bool all_unreclaimable = true; > + > + for_each_zone_zonelist_nodemask(zone, z, zonelist, > + gfp_zone(sc->gfp_mask), sc->nodemask) { > + if (!populated_zone(zone)) > + continue; > + if (zone->pages_scanned < (zone_reclaimable_pages(zone) * 6)) { > + all_unreclaimable = false; > + break; > + } > + } > + > return all_unreclaimable; > } > > @@ -1926,7 +1942,6 @@ static unsigned long do_try_to_free_pages(struct > zonelist *zonelist, > struct scan_control *sc) > { > int priority; > - bool all_unreclaimable; > unsigned long total_scanned = 0; > struct reclaim_state *reclaim_state = current->reclaim_state; > struct zoneref *z; > @@ -1943,7 +1958,7 @@ static unsigned long do_try_to_free_pages(struct > zonelist *zonelist, > sc->nr_scanned = 0; > if (!priority) > disable_swap_token(); > - all_unreclaimable = shrink_zones(priority, zonelist, sc); > + shrink_zones(priority, zonelist, sc); > /* > * Don't shrink slabs when reclaiming memory from > * over limit cgroups > @@ -2005,7 +2020,7 @@ out: > return sc->nr_reclaimed; > > /* top priority shrink_zones still had more to do? don't OOM, then */ > - if (scanning_global_lru(sc) && !all_unreclaimable) > + if (scanning_global_lru(sc) && !all_unreclaimable(zonelist, sc)) > return 1; > > return 0; > > > -- > Kind regards, > Minchan Kim