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=-11.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham 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 65089C433E0 for ; Wed, 5 Aug 2020 19:58:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3A98222CA0 for ; Wed, 5 Aug 2020 19:58:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729742AbgHET6j (ORCPT ); Wed, 5 Aug 2020 15:58:39 -0400 Received: from out30-45.freemail.mail.aliyun.com ([115.124.30.45]:41933 "EHLO out30-45.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727039AbgHEQmY (ORCPT ); Wed, 5 Aug 2020 12:42:24 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R541e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01f04427;MF=alex.shi@linux.alibaba.com;NM=1;PH=DS;RN=7;SR=0;TI=SMTPD_---0U4paFMA_1596632569; Received: from IT-FVFX43SYHV2H.local(mailfrom:alex.shi@linux.alibaba.com fp:SMTPD_---0U4paFMA_1596632569) by smtp.aliyun-inc.com(127.0.0.1); Wed, 05 Aug 2020 21:02:49 +0800 Subject: Re: [PATCH] mm/memcg: remove useless check on page->mem_cgroup From: Alex Shi To: Michal Hocko Cc: Johannes Weiner , Vladimir Davydov , Andrew Morton , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <1596166480-22814-1-git-send-email-alex.shi@linux.alibaba.com> <20200731151655.GB491801@cmpxchg.org> <9338716f-ca0e-057f-8d94-03e2b3f70281@linux.alibaba.com> <20200803081815.GD5174@dhcp22.suse.cz> <92dd8e68-8095-72c5-0144-2a084e4d5993@linux.alibaba.com> Message-ID: <5622ef68-5e70-d1a9-d1be-b45411b6be5c@linux.alibaba.com> Date: Wed, 5 Aug 2020 21:02:30 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <92dd8e68-8095-72c5-0144-2a084e4d5993@linux.alibaba.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2020/8/5 下午8:28, Alex Shi 写道: > The last patch has a problem on define. this version could fix it. > > BTW, I see some !memcg happens when MEMCG compilered but disabled by cgroup_disable > > > [ 94.657666] ---[ end trace f1f34bfc3b32ed2f ]--- > [ 95.138995] anon flags: 0x5005b48008000d(locked|uptodate|dirty|swapbacked) > [ 95.146220] raw: 005005b48008000d dead000000000100 dead000000000122 ffff8897c7c76ad1 > [ 95.154549] raw: 0000000000000022 0000000000000000 0000000200000000 0000000000000000 > [ 95.162876] page dumped because: VM_WARN_ON_ONCE_PAGE(!memcg) > > The following patch may helpful. >From 8bfb26a2e37e08dc61d20212bcfa5812a367ba94 Mon Sep 17 00:00:00 2001 From: Alex Shi Date: Wed, 5 Aug 2020 20:32:12 +0800 Subject: [PATCH] mm/memcg: don't try charge swap if memcg disabled If we disabled memcg by cgroup_disable=memory, the swap charges are still called. Let's return from the funcs earlier and keep WARN_ON monitor. Signed-off-by: Alex Shi Cc: Johannes Weiner Cc: Michal Hocko Cc: Vladimir Davydov Cc: Andrew Morton Cc: cgroups@vger.kernel.org Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org --- mm/memcontrol.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index cb07a48d53aa..65f2b42d25af 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -7163,6 +7163,9 @@ void mem_cgroup_swapout(struct page *page, swp_entry_t entry) VM_BUG_ON_PAGE(PageLRU(page), page); VM_BUG_ON_PAGE(page_count(page), page); + if (mem_cgroup_disabled()) + return; + if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) return; @@ -7228,6 +7231,9 @@ int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry) struct mem_cgroup *memcg; unsigned short oldid; + if (mem_cgroup_disabled()) + return 0; + if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) return 0; -- 1.8.3.1