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=-12.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 EF5A0C43460 for ; Sat, 11 Jul 2020 00:59:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D7ADB2078B for ; Sat, 11 Jul 2020 00:59:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728028AbgGKA7x (ORCPT ); Fri, 10 Jul 2020 20:59:53 -0400 Received: from out30-45.freemail.mail.aliyun.com ([115.124.30.45]:52139 "EHLO out30-45.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727086AbgGKA7N (ORCPT ); Fri, 10 Jul 2020 20:59:13 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R151e4;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=17;SR=0;TI=SMTPD_---0U2KGAZr_1594429139; Received: from alexshi-test.localdomain(mailfrom:alex.shi@linux.alibaba.com fp:SMTPD_---0U2KGAZr_1594429139) by smtp.aliyun-inc.com(127.0.0.1); Sat, 11 Jul 2020 08:59:06 +0800 From: Alex Shi To: akpm@linux-foundation.org, mgorman@techsingularity.net, tj@kernel.org, hughd@google.com, khlebnikov@yandex-team.ru, daniel.m.jordan@oracle.com, yang.shi@linux.alibaba.com, willy@infradead.org, hannes@cmpxchg.org, lkp@intel.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, shakeelb@google.com, iamjoonsoo.kim@lge.com, richard.weiyang@gmail.com, kirill@shutemov.name Subject: [PATCH v16 17/22] mm/swap: serialize memcg changes during pagevec_lru_move_fn Date: Sat, 11 Jul 2020 08:58:51 +0800 Message-Id: <1594429136-20002-18-git-send-email-alex.shi@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1594429136-20002-1-git-send-email-alex.shi@linux.alibaba.com> References: <1594429136-20002-1-git-send-email-alex.shi@linux.alibaba.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hugh Dickins' found a memcg change bug on original version: If we want to change the pgdat->lru_lock to memcg's lruvec lock, we have to serialize mem_cgroup_move_account during pagevec_lru_move_fn. The possible bad scenario would like: cpu 0 cpu 1 lruvec = mem_cgroup_page_lruvec() if (!isolate_lru_page()) mem_cgroup_move_account spin_lock_irqsave(&lruvec->lru_lock <== wrong lock. So we need the ClearPageLRU to block isolate_lru_page(), then serialize the memcg change here. Reported-by: Hugh Dickins Signed-off-by: Alex Shi Cc: Andrew Morton Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org --- mm/swap.c | 30 +++++++++++++++++++++++++++++- 1 file changed, 29 insertions(+), 1 deletion(-) diff --git a/mm/swap.c b/mm/swap.c index 5092fe9c8c47..8488b9b25730 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -221,8 +221,14 @@ static void pagevec_lru_move_fn(struct pagevec *pvec, spin_lock_irqsave(&pgdat->lru_lock, flags); } + /* block memcg migration during page moving between lru */ + if (!TestClearPageLRU(page)) + continue; + lruvec = mem_cgroup_page_lruvec(page, pgdat); (*move_fn)(page, lruvec); + + SetPageLRU(page); } if (pgdat) spin_unlock_irqrestore(&pgdat->lru_lock, flags); @@ -976,7 +982,29 @@ static void __pagevec_lru_add_fn(struct page *page, struct lruvec *lruvec) */ void __pagevec_lru_add(struct pagevec *pvec) { - pagevec_lru_move_fn(pvec, __pagevec_lru_add_fn); + int i; + struct pglist_data *pgdat = NULL; + struct lruvec *lruvec; + unsigned long flags = 0; + + for (i = 0; i < pagevec_count(pvec); i++) { + struct page *page = pvec->pages[i]; + struct pglist_data *pagepgdat = page_pgdat(page); + + if (pagepgdat != pgdat) { + if (pgdat) + spin_unlock_irqrestore(&pgdat->lru_lock, flags); + pgdat = pagepgdat; + spin_lock_irqsave(&pgdat->lru_lock, flags); + } + + lruvec = mem_cgroup_page_lruvec(page, pgdat); + __pagevec_lru_add_fn(page, lruvec); + } + if (pgdat) + spin_unlock_irqrestore(&pgdat->lru_lock, flags); + release_pages(pvec->pages, pvec->nr); + pagevec_reinit(pvec); } /** -- 1.8.3.1