From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 601AFC433DF for ; Fri, 21 Aug 2020 13:48:47 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 2A1B320578 for ; Fri, 21 Aug 2020 13:48:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2A1B320578 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id AD4D28D0006; Fri, 21 Aug 2020 09:48:46 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A86428D0001; Fri, 21 Aug 2020 09:48:46 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 99A8A8D0006; Fri, 21 Aug 2020 09:48:46 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0214.hostedemail.com [216.40.44.214]) by kanga.kvack.org (Postfix) with ESMTP id 811338D0001 for ; Fri, 21 Aug 2020 09:48:46 -0400 (EDT) Received: from smtpin03.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 3D2A3246E for ; Fri, 21 Aug 2020 13:48:46 +0000 (UTC) X-FDA: 77174706252.03.bear95_26036a127039 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin03.hostedemail.com (Postfix) with ESMTP id 0ED6F28A4E9 for ; Fri, 21 Aug 2020 13:48:46 +0000 (UTC) X-HE-Tag: bear95_26036a127039 X-Filterd-Recvd-Size: 2824 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf08.hostedemail.com (Postfix) with ESMTP for ; Fri, 21 Aug 2020 13:48:45 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 37F43B148; Fri, 21 Aug 2020 13:49:12 +0000 (UTC) Date: Fri, 21 Aug 2020 15:48:42 +0200 From: Michal Hocko To: Qian Cai Cc: Alex Shi , akpm@linux-foundation.org, Johannes Weiner , Vladimir Davydov , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, nao.horiguchi@gmail.com, osalvador@suse.de, mike.kravetz@oracle.com Subject: Re: [Resend PATCH 1/6] mm/memcg: warning on !memcg after readahead page charged Message-ID: <20200821134842.GF32537@dhcp22.suse.cz> References: <1597144232-11370-1-git-send-email-alex.shi@linux.alibaba.com> <20200820145850.GA4622@lca.pw> <20200821080127.GD32537@dhcp22.suse.cz> <20200821123934.GA4314@lca.pw> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200821123934.GA4314@lca.pw> X-Rspamd-Queue-Id: 0ED6F28A4E9 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam05 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri 21-08-20 08:39:37, Qian Cai wrote: > On Fri, Aug 21, 2020 at 10:01:27AM +0200, Michal Hocko wrote: > > On Thu 20-08-20 10:58:51, Qian Cai wrote: > > > On Tue, Aug 11, 2020 at 07:10:27PM +0800, Alex Shi wrote: > > > > Since readahead page is charged on memcg too, in theory we don't have to > > > > check this exception now. Before safely remove them all, add a warning > > > > for the unexpected !memcg. > > > > > > > > Signed-off-by: Alex Shi > > > > Acked-by: Michal Hocko > > > > > > This will trigger, > > > > Thanks for the report! > > > > > [ 1863.916499] LTP: starting move_pages12 > > > [ 1863.946520] page:000000008ccc1062 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1fd3c0 > > > [ 1863.946553] head:000000008ccc1062 order:5 compound_mapcount:0 compound_pincount:0 > > > > Hmm, this is really unexpected. How did we get order-5 page here? Is > > this some special mappaing that sys_move_pages should just ignore? > > Well, I thought everybody should be able to figure out where to find the LTP > tests source code at this stage to see what it does. Anyway, the test simply > migrate hugepages while soft offlining, so order 5 is expected as that is 2M > hugepage on powerpc (also reproduced on x86 below). It might be easier to > reproduce using our linux-mm random bug collection on NUMA systems. OK, I must have missed that this was on ppc. The order makes more sense now. I will have a look at this next week. Thanks! -- Michal Hocko SUSE Labs