Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754766Ab1EDBjQ (ORCPT ); Tue, 3 May 2011 21:39:16 -0400 Received: from mx4-phx2.redhat.com ([209.132.183.25]:49508 "EHLO mx4-phx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754663Ab1EDBjK (ORCPT ); Tue, 3 May 2011 21:39:10 -0400 Date: Tue, 3 May 2011 21:38:39 -0400 (EDT) From: CAI Qian To: avagin@gmail.com Cc: Andrey Vagin , Andrew Morton , Mel Gorman , KOSAKI Motohiro , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Minchan Kim Message-ID: <1593977838.225469.1304473119444.JavaMail.root@zmail06.collab.prod.int.phx2.redhat.com> In-Reply-To: <4D72580D.4000208@gmail.com> Subject: Re: [PATCH] mm: check zone->all_unreclaimable in all_unreclaimable() MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_225468_1867416694.1304473119443" X-Originating-IP: [10.5.5.72] X-Mailer: Zimbra 6.0.9_GA_2686 (ZimbraWebClient - FF3.0 (Linux)/6.0.9_GA_2686) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3528 Lines: 94 ------=_Part_225468_1867416694.1304473119443 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit ----- Original Message ----- > On 03/05/2011 06:20 PM, Minchan Kim wrote: > > On Sat, Mar 05, 2011 at 02:44:16PM +0300, Andrey Vagin wrote: > >> Check zone->all_unreclaimable in all_unreclaimable(), otherwise the > >> kernel may hang up, because shrink_zones() will do nothing, but > >> all_unreclaimable() will say, that zone has reclaimable pages. > >> > >> do_try_to_free_pages() > >> shrink_zones() > >> for_each_zone > >> if (zone->all_unreclaimable) > >> continue > >> if !all_unreclaimable(zonelist, sc) > >> return 1 > >> > >> __alloc_pages_slowpath() > >> retry: > >> did_some_progress = do_try_to_free_pages(page) > >> ... > >> if (!page&& did_some_progress) > >> retry; > >> > >> Signed-off-by: Andrey Vagin > >> --- > >> mm/vmscan.c | 2 ++ > >> 1 files changed, 2 insertions(+), 0 deletions(-) > >> > >> diff --git a/mm/vmscan.c b/mm/vmscan.c > >> index 6771ea7..1c056f7 100644 > >> --- a/mm/vmscan.c > >> +++ b/mm/vmscan.c > >> @@ -2002,6 +2002,8 @@ static bool all_unreclaimable(struct zonelist > >> *zonelist, > >> > >> for_each_zone_zonelist_nodemask(zone, z, zonelist, > >> gfp_zone(sc->gfp_mask), sc->nodemask) { > >> + if (zone->all_unreclaimable) > >> + continue; > >> if (!populated_zone(zone)) > >> continue; > >> if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL)) > > > > zone_reclaimable checks it. Isn't it enough? > I sent one more patch [PATCH] mm: skip zombie in OOM-killer. > This two patches are enough. > > Does the hang up really happen or see it by code review? > Yes. You can reproduce it for help the attached python program. It's > not > very clever:) > It make the following actions in loop: > 1. fork > 2. mmap > 3. touch memory > 4. read memory > 5. munmmap > > >> -- > >> 1.7.1 I have tested this for the latest mainline kernel using the reproducer attached, the system just hung or deadlock after oom. The whole oom trace is here. http://people.redhat.com/qcai/oom.log Did I miss anything? ------=_Part_225468_1867416694.1304473119443 Content-Type: text/plain; name=memeater.py Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename=memeater.py aW1wb3J0IHN5cywgdGltZSwgbW1hcCwgb3MNCmZyb20gc3VicHJvY2VzcyBpbXBvcnQgUG9wZW4s IFBJUEUNCmltcG9ydCByYW5kb20NCg0KZ2xvYmFsIG1lbV9zaXplDQoNCmRlZiBpbmZvKG1zZyk6 DQoJcGlkID0gb3MuZ2V0cGlkKCkNCglwcmludCA+PiBzeXMuc3RkZXJyLCAiJXM6ICVzIiAlIChw aWQsIG1zZykNCglzeXMuc3RkZXJyLmZsdXNoKCkNCg0KDQoNCmRlZiBtZW1vcnlfbG9vcChjbWQg PSAiYSIpOg0KCSIiIg0KCWNtZCBtYXkgYmU6DQoJCWM6IGNoZWNrIG1lbW9yeQ0KCQllbHNlOiB0 b3VjaCBtZW1vcnkNCgkiIiINCgljID0gMA0KCWZvciBqIGluIHhyYW5nZSgwLCBtZW1fc2l6ZSk6 DQoJCWlmIGNtZCA9PSAiYyI6DQoJCQlpZiBmW2o8PDEyXSAhPSBjaHIoaiAlIDI1NSk6DQoJCQkJ aW5mbygiRGF0YSBjb3JydXB0aW9uIikNCgkJCQlzeXMuZXhpdCgxKQ0KCQllbHNlOg0KCQkJZltq PDwxMl0gPSBjaHIoaiAlIDI1NSkNCg0Kd2hpbGUgVHJ1ZToNCglwaWQgPSBvcy5mb3JrKCkNCglp ZiAocGlkICE9IDApOg0KCQltZW1fc2l6ZSA9IHJhbmRvbS5yYW5kaW50KDAsIDU2ICogNDA5NikN CgkJZiA9IG1tYXAubW1hcCgtMSwgbWVtX3NpemUgPDwgMTIsIG1tYXAuTUFQX0FOT05ZTU9VU3xt bWFwLk1BUF9QUklWQVRFKQ0KCQltZW1vcnlfbG9vcCgpDQoJCW1lbW9yeV9sb29wKCJjIikNCgkJ Zi5jbG9zZSgpDQo= ------=_Part_225468_1867416694.1304473119443-- -- 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/