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=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED, USER_AGENT_GIT 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 B8561C63697 for ; Fri, 27 Nov 2020 03:08:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 75E242222B for ; Fri, 27 Nov 2020 03:08:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392295AbgK0DIm (ORCPT ); Thu, 26 Nov 2020 22:08:42 -0500 Received: from out30-42.freemail.mail.aliyun.com ([115.124.30.42]:60086 "EHLO out30-42.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2392286AbgK0DIm (ORCPT ); Thu, 26 Nov 2020 22:08:42 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R441e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04420;MF=alex.shi@linux.alibaba.com;NM=1;PH=DS;RN=10;SR=0;TI=SMTPD_---0UGebCV9_1606446518; Received: from aliy80.localdomain(mailfrom:alex.shi@linux.alibaba.com fp:SMTPD_---0UGebCV9_1606446518) by smtp.aliyun-inc.com(127.0.0.1); Fri, 27 Nov 2020 11:08:38 +0800 From: Alex Shi Cc: Andrew Morton , Johannes Weiner , Shakeel Butt , Roman Gushchin , Lorenzo Stoakes , Stephen Rothwell , Alexander Duyck , Yafang Shao , Wei Yang , linux-kernel@vger.kernel.org Subject: [PATCH] mm/memcg: bail out early when !memcg in mem_cgroup_lruvec Date: Fri, 27 Nov 2020 11:08:35 +0800 Message-Id: <1606446515-36069-1-git-send-email-alex.shi@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 To: unlisted-recipients:; (no To-header on input) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Sometime, we use NULL memcg in mem_cgroup_lruvec(memcg, pgdat) so we could get out early in the situation to avoid useless checking. Also warning if both parameter are NULL. Signed-off-by: Alex Shi Cc: Andrew Morton Cc: Johannes Weiner Cc: Shakeel Butt Cc: Roman Gushchin Cc: Lorenzo Stoakes Cc: Stephen Rothwell Cc: Alexander Duyck Cc: Yafang Shao Cc: Wei Yang Cc: linux-kernel@vger.kernel.org --- include/linux/memcontrol.h | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 3e6a1df3bdb9..4cdb110f84e0 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -613,14 +613,13 @@ static inline struct lruvec *mem_cgroup_lruvec(struct mem_cgroup *memcg, struct mem_cgroup_per_node *mz; struct lruvec *lruvec; - if (mem_cgroup_disabled()) { + VM_WARN_ON_ONCE(!memcg && !pgdat); + + if (mem_cgroup_disabled() || !memcg) { lruvec = &pgdat->__lruvec; goto out; } - if (!memcg) - memcg = root_mem_cgroup; - mz = mem_cgroup_nodeinfo(memcg, pgdat->node_id); lruvec = &mz->lruvec; out: -- 2.29.GIT