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 01346C00A89 for ; Thu, 5 Nov 2020 08:57:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B25C0206FB for ; Thu, 5 Nov 2020 08:57:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731492AbgKEI5Y (ORCPT ); Thu, 5 Nov 2020 03:57:24 -0500 Received: from out30-56.freemail.mail.aliyun.com ([115.124.30.56]:47930 "EHLO out30-56.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730567AbgKEI4V (ORCPT ); Thu, 5 Nov 2020 03:56:21 -0500 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=e01e04357;MF=alex.shi@linux.alibaba.com;NM=1;PH=DS;RN=21;SR=0;TI=SMTPD_---0UEJC3Fv_1604566567; Received: from aliy80.localdomain(mailfrom:alex.shi@linux.alibaba.com fp:SMTPD_---0UEJC3Fv_1604566567) by smtp.aliyun-inc.com(127.0.0.1); Thu, 05 Nov 2020 16:56:14 +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, 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, alexander.duyck@gmail.com, rong.a.chen@intel.com, mhocko@suse.com, vdavydov.dev@gmail.com, shy828301@gmail.com Subject: [PATCH v21 16/19] mm/swap.c: serialize memcg changes in pagevec_lru_move_fn Date: Thu, 5 Nov 2020 16:55:46 +0800 Message-Id: <1604566549-62481-17-git-send-email-alex.shi@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1604566549-62481-1-git-send-email-alex.shi@linux.alibaba.com> References: <1604566549-62481-1-git-send-email-alex.shi@linux.alibaba.com> 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 TestClearPageLRU to block isolate_lru_page(), that serializes the memcg change. and then removing the PageLRU check in move_fn callee as the consequence. __pagevec_lru_add_fn() is different from the others, because the pages it deals with are, by definition, not yet on the lru. TestClearPageLRU is not needed and would not work, so __pagevec_lru_add() goes its own way. Reported-by: Hugh Dickins Signed-off-by: Alex Shi Acked-by: Hugh Dickins Acked-by: Johannes Weiner Cc: Andrew Morton Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org --- mm/swap.c | 44 +++++++++++++++++++++++++++++++++++--------- 1 file changed, 35 insertions(+), 9 deletions(-) diff --git a/mm/swap.c b/mm/swap.c index 2681d9023998..1838a9535703 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -222,8 +222,14 @@ 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); @@ -233,7 +239,7 @@ static void pagevec_lru_move_fn(struct pagevec *pvec, static void pagevec_move_tail_fn(struct page *page, struct lruvec *lruvec) { - if (PageLRU(page) && !PageUnevictable(page)) { + if (!PageUnevictable(page)) { del_page_from_lru_list(page, lruvec, page_lru(page)); ClearPageActive(page); add_page_to_lru_list_tail(page, lruvec, page_lru(page)); @@ -306,7 +312,7 @@ void lru_note_cost_page(struct page *page) static void __activate_page(struct page *page, struct lruvec *lruvec) { - if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) { + if (!PageActive(page) && !PageUnevictable(page)) { int lru = page_lru_base_type(page); int nr_pages = thp_nr_pages(page); @@ -362,7 +368,8 @@ static void activate_page(struct page *page) page = compound_head(page); spin_lock_irq(&pgdat->lru_lock); - __activate_page(page, mem_cgroup_page_lruvec(page, pgdat)); + if (PageLRU(page)) + __activate_page(page, mem_cgroup_page_lruvec(page, pgdat)); spin_unlock_irq(&pgdat->lru_lock); } #endif @@ -519,9 +526,6 @@ static void lru_deactivate_file_fn(struct page *page, struct lruvec *lruvec) bool active; int nr_pages = thp_nr_pages(page); - if (!PageLRU(page)) - return; - if (PageUnevictable(page)) return; @@ -562,7 +566,7 @@ static void lru_deactivate_file_fn(struct page *page, struct lruvec *lruvec) static void lru_deactivate_fn(struct page *page, struct lruvec *lruvec) { - if (PageLRU(page) && PageActive(page) && !PageUnevictable(page)) { + if (PageActive(page) && !PageUnevictable(page)) { int lru = page_lru_base_type(page); int nr_pages = thp_nr_pages(page); @@ -579,7 +583,7 @@ static void lru_deactivate_fn(struct page *page, struct lruvec *lruvec) static void lru_lazyfree_fn(struct page *page, struct lruvec *lruvec) { - if (PageLRU(page) && PageAnon(page) && PageSwapBacked(page) && + if (PageAnon(page) && PageSwapBacked(page) && !PageSwapCache(page) && !PageUnevictable(page)) { bool active = PageActive(page); int nr_pages = thp_nr_pages(page); @@ -1021,7 +1025,29 @@ 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