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 1A427C2BB40 for ; Thu, 17 Dec 2020 06:29:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D973923372 for ; Thu, 17 Dec 2020 06:29:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727117AbgLQG3q (ORCPT ); Thu, 17 Dec 2020 01:29:46 -0500 Received: from out30-130.freemail.mail.aliyun.com ([115.124.30.130]:50590 "EHLO out30-130.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726862AbgLQG3q (ORCPT ); Thu, 17 Dec 2020 01:29:46 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R111e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04394;MF=alex.shi@linux.alibaba.com;NM=1;PH=DS;RN=8;SR=0;TI=SMTPD_---0UItliQ7_1608186540; Received: from aliy80.localdomain(mailfrom:alex.shi@linux.alibaba.com fp:SMTPD_---0UItliQ7_1608186540) by smtp.aliyun-inc.com(127.0.0.1); Thu, 17 Dec 2020 14:29:01 +0800 From: Alex Shi To: akpm@linux-foundation.org Cc: Hugh Dickins , Johannes Weiner , Michal Hocko , Vladimir Davydov , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH 2/3] mm/memcg: remove rcu locking for lock_page_lruvec function series Date: Thu, 17 Dec 2020 14:28:51 +0800 Message-Id: <1608186532-81218-2-git-send-email-alex.shi@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1608186532-81218-1-git-send-email-alex.shi@linux.alibaba.com> References: <1608186532-81218-1-git-send-email-alex.shi@linux.alibaba.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The rcu_read_lock was used to block memcg destory, but with the detailed calling conditions, the memcg won't gone since the page is hold. So we don't need it now, let's remove them to save locking load in debugging. Signed-off-by: Alex Shi Cc: Hugh Dickins 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 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index e6b50d068b2f..98bbee1d2faf 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1356,10 +1356,8 @@ struct lruvec *lock_page_lruvec(struct page *page) struct lruvec *lruvec; struct pglist_data *pgdat = page_pgdat(page); - rcu_read_lock(); lruvec = mem_cgroup_page_lruvec(page, pgdat); spin_lock(&lruvec->lru_lock); - rcu_read_unlock(); lruvec_memcg_debug(lruvec, page); @@ -1371,10 +1369,8 @@ struct lruvec *lock_page_lruvec_irq(struct page *page) struct lruvec *lruvec; struct pglist_data *pgdat = page_pgdat(page); - rcu_read_lock(); lruvec = mem_cgroup_page_lruvec(page, pgdat); spin_lock_irq(&lruvec->lru_lock); - rcu_read_unlock(); lruvec_memcg_debug(lruvec, page); @@ -1386,10 +1382,8 @@ struct lruvec *lock_page_lruvec_irqsave(struct page *page, unsigned long *flags) struct lruvec *lruvec; struct pglist_data *pgdat = page_pgdat(page); - rcu_read_lock(); lruvec = mem_cgroup_page_lruvec(page, pgdat); spin_lock_irqsave(&lruvec->lru_lock, *flags); - rcu_read_unlock(); lruvec_memcg_debug(lruvec, page); -- 2.29.GIT