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,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 9E96AC43214 for ; Sat, 14 Aug 2021 05:26:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8AF1260F14 for ; Sat, 14 Aug 2021 05:26:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237467AbhHNF1M (ORCPT ); Sat, 14 Aug 2021 01:27:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42148 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237345AbhHNF1K (ORCPT ); Sat, 14 Aug 2021 01:27:10 -0400 Received: from mail-pj1-x1036.google.com (mail-pj1-x1036.google.com [IPv6:2607:f8b0:4864:20::1036]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1DD26C061757 for ; Fri, 13 Aug 2021 22:26:43 -0700 (PDT) Received: by mail-pj1-x1036.google.com with SMTP id j1so18404938pjv.3 for ; Fri, 13 Aug 2021 22:26:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=F7om0JAa0251atdQthJaeQsHZPzAeTPpBSU7iFofJt8=; b=cpjKGrBcADQ43V3XCL+krFmngOlt6LDMzJ8yojIYlCDgPodVgLxGUqn57l4LwtfCAf tIKpZQ8voojunBk1mckjz65YDkE1V6gvVEjXq+IRHBYY8wGX/eMrCISR9NJGArx/luDf tnGwv5WxqxOJnCBqsgIFSUnQDAMmmy3Z+Mfruqqq2OIWON0EVhOWpTVrsb+s2QBGwWS+ OKydRi58D3MLlPpqAodC9EvyJ06Bv3QMLeOu4ZCYfP1+Y4kMLGK/wgawxAcUa6ChGcqE fEeKNtpiZnDduu4Z7EcONhCj3OnUH1+WuLGGmuBlIePpr4hB8R0N8cVStnfme1a2ZkBw LjuA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=F7om0JAa0251atdQthJaeQsHZPzAeTPpBSU7iFofJt8=; b=pX+ACQXOwQJn3q7oJtD9IyN588zot5sf68DQTMuYHuRjAWLeHxzCLwaEeq1/PfKK5E CrBtoiFFVCNcjOOcDXjhxljcCv1iEmRMrP55fCmEd5rmAIo9GyltaU04e5e+VejvV2lc zTNKlnrG+9N5hhPi7WaO0QWwCHHezWRs0AhTi5CnMm1hltV0n0tEZQ6b1FrIO6Rj1GP4 wgRoOkywVB3mXJNKFkrZgpgg8y2o9eyX8ibhvNNlvVhDnLp8cb5ImDOS2vVoEhH+atL2 yvdm9z9DMlAMb8848JltQiQ1Inm3SF+1LG1poSHVUTfzz3qUCc/4bMUwG6UKhQD+vlDf 3cVQ== X-Gm-Message-State: AOAM530N/2z9MdcFtv5QslRDpwt9f2+iGO33gl+wsZKywf/kuzZYjLTO QWGpEbjUO+vk2VN+mdUK6qG8+A== X-Google-Smtp-Source: ABdhPJxtyMotRT3YcEMVp8oZNI/9l5Jq9kgUWY3mGX+e67YoWP7YJJfIybQYf6pC/184WHjV0eCAwA== X-Received: by 2002:a62:1a03:0:b029:3e0:30aa:5172 with SMTP id a3-20020a621a030000b02903e030aa5172mr5737900pfa.69.1628918802677; Fri, 13 Aug 2021 22:26:42 -0700 (PDT) Received: from localhost.localdomain ([139.177.225.237]) by smtp.gmail.com with ESMTPSA id s5sm4783133pgp.81.2021.08.13.22.26.37 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Fri, 13 Aug 2021 22:26:42 -0700 (PDT) From: Muchun Song To: guro@fb.com, hannes@cmpxchg.org, mhocko@kernel.org, akpm@linux-foundation.org, shakeelb@google.com, vdavydov.dev@gmail.com Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, duanxiongchun@bytedance.com, fam.zheng@bytedance.com, bsingharora@gmail.com, shy828301@gmail.com, alexs@kernel.org, smuchun@gmail.com, zhengqi.arch@bytedance.com, Muchun Song Subject: [PATCH v1 12/12] mm: lru: use lruvec lock to serialize memcg changes Date: Sat, 14 Aug 2021 13:25:19 +0800 Message-Id: <20210814052519.86679-13-songmuchun@bytedance.com> X-Mailer: git-send-email 2.21.0 (Apple Git-122) In-Reply-To: <20210814052519.86679-1-songmuchun@bytedance.com> References: <20210814052519.86679-1-songmuchun@bytedance.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org As described by commit fc574c23558c ("mm/swap.c: serialize memcg changes in pagevec_lru_move_fn"), TestClearPageLRU() aims to serialize mem_cgroup_move_account() during pagevec_lru_move_fn(). Now folio_lruvec_lock*() has the ability to detect whether page memcg has been changed. So we can use lruvec lock to serialize mem_cgroup_move_account() during pagevec_lru_move_fn(). This change is a partial revert of the commit fc574c23558c ("mm/swap.c: serialize memcg changes in pagevec_lru_move_fn"). And pagevec_lru_move_fn() is more hot compare with mem_cgroup_move_account(), removing an atomic operation would be an optimization. Also this change would not dirty cacheline for a page which isn't on the LRU. Signed-off-by: Muchun Song --- mm/memcontrol.c | 31 +++++++++++++++++++++++++++++++ mm/swap.c | 45 ++++++++++++++------------------------------- mm/vmscan.c | 9 ++++----- 3 files changed, 49 insertions(+), 36 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 9464e6d2d735..7732ccf7d180 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1286,12 +1286,38 @@ struct lruvec *folio_lruvec_lock(struct folio *folio) lruvec = folio_lruvec(folio); spin_lock(&lruvec->lru_lock); + /* + * The memcg of the page can be changed by any the following routines: + * + * 1) mem_cgroup_move_account() or + * 2) memcg_reparent_objcgs() + * + * The possible bad scenario would like: + * + * CPU0: CPU1: CPU2: + * lruvec = folio_lruvec() + * + * if (!isolate_lru_page()) + * mem_cgroup_move_account() + * + * memcg_reparent_objcgs() + * + * spin_lock(&lruvec->lru_lock) + * ^^^^^^ + * wrong lock + * + * Either CPU1 or CPU2 can change page memcg, so we need to check + * whether page memcg is changed, if so, we should reacquire the + * new lruvec lock. + */ if (unlikely(lruvec_memcg(lruvec) != folio_memcg(folio))) { spin_unlock(&lruvec->lru_lock); goto retry; } /* + * When we reach here, it means that the folio_memcg(folio) is stable. + * * Preemption is disabled in the internal of spin_lock, which can serve * as RCU read-side critical sections. */ @@ -1309,6 +1335,7 @@ struct lruvec *folio_lruvec_lock_irq(struct folio *folio) lruvec = folio_lruvec(folio); spin_lock_irq(&lruvec->lru_lock); + /* See the comments in folio_lruvec_lock(). */ if (unlikely(lruvec_memcg(lruvec) != folio_memcg(folio))) { spin_unlock_irq(&lruvec->lru_lock); goto retry; @@ -1330,6 +1357,7 @@ struct lruvec *folio_lruvec_lock_irqsave(struct folio *folio, lruvec = folio_lruvec(folio); spin_lock_irqsave(&lruvec->lru_lock, *flags); + /* See the comments in folio_lruvec_lock(). */ if (unlikely(lruvec_memcg(lruvec) != folio_memcg(folio))) { spin_unlock_irqrestore(&lruvec->lru_lock, *flags); goto retry; @@ -5836,7 +5864,10 @@ static int mem_cgroup_move_account(struct page *page, obj_cgroup_get(to->objcg); obj_cgroup_put(from->objcg); + /* See the comments in folio_lruvec_lock(). */ + spin_lock(&from_vec->lru_lock); folio->memcg_data = (unsigned long)to->objcg; + spin_unlock(&from_vec->lru_lock); __folio_memcg_unlock(from); diff --git a/mm/swap.c b/mm/swap.c index 9554ff008fe6..00b6776860e8 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -191,14 +191,8 @@ static void pagevec_lru_move_fn(struct pagevec *pvec, struct page *page = pvec->pages[i]; struct folio *folio = page_folio(page); - /* block memcg migration during page moving between lru */ - if (!TestClearPageLRU(page)) - continue; - lruvec = folio_lruvec_relock_irqsave(folio, lruvec, &flags); (*move_fn)(page, lruvec); - - SetPageLRU(page); } if (lruvec) unlock_page_lruvec_irqrestore(lruvec, flags); @@ -210,7 +204,7 @@ static void pagevec_move_tail_fn(struct page *page, struct lruvec *lruvec) { struct folio *folio = page_folio(page); - if (!folio_test_unevictable(folio)) { + if (folio_test_lru(folio) && !folio_test_unevictable(folio)) { lruvec_del_folio(lruvec, folio); folio_clear_active(folio); lruvec_add_folio_tail(lruvec, folio); @@ -305,7 +299,8 @@ void lru_note_cost_folio(struct folio *folio) static void __folio_activate(struct folio *folio, struct lruvec *lruvec) { - if (!folio_test_active(folio) && !folio_test_unevictable(folio)) { + if (folio_test_lru(folio) && !folio_test_active(folio) && + !folio_test_unevictable(folio)) { long nr_pages = folio_nr_pages(folio); lruvec_del_folio(lruvec, folio); @@ -362,12 +357,9 @@ static void folio_activate(struct folio *folio) { struct lruvec *lruvec; - if (folio_test_clear_lru(folio)) { - lruvec = folio_lruvec_lock_irq(folio); - __folio_activate(folio, lruvec); - unlock_page_lruvec_irq(lruvec); - folio_set_lru(folio); - } + lruvec = folio_lruvec_lock_irq(folio); + __folio_activate(folio, lruvec); + unlock_page_lruvec_irq(lruvec); } #endif @@ -520,6 +512,9 @@ static void lru_deactivate_file_fn(struct page *page, struct lruvec *lruvec) bool active = PageActive(page); int nr_pages = thp_nr_pages(page); + if (!PageLRU(page)) + return; + if (PageUnevictable(page)) return; @@ -557,7 +552,7 @@ static void lru_deactivate_file_fn(struct page *page, struct lruvec *lruvec) static void lru_deactivate_fn(struct page *page, struct lruvec *lruvec) { - if (PageActive(page) && !PageUnevictable(page)) { + if (PageLRU(page) && PageActive(page) && !PageUnevictable(page)) { int nr_pages = thp_nr_pages(page); del_page_from_lru_list(page, lruvec); @@ -573,7 +568,7 @@ static void lru_deactivate_fn(struct page *page, struct lruvec *lruvec) static void lru_lazyfree_fn(struct page *page, struct lruvec *lruvec) { - if (PageAnon(page) && PageSwapBacked(page) && + if (PageLRU(page) && PageAnon(page) && PageSwapBacked(page) && !PageSwapCache(page) && !PageUnevictable(page)) { int nr_pages = thp_nr_pages(page); @@ -983,8 +978,9 @@ void __pagevec_release(struct pagevec *pvec) } EXPORT_SYMBOL(__pagevec_release); -static void __pagevec_lru_add_fn(struct folio *folio, struct lruvec *lruvec) +static void __pagevec_lru_add_fn(struct page *page, struct lruvec *lruvec) { + struct folio *folio = page_folio(page); int was_unevictable = folio_test_clear_unevictable(folio); long nr_pages = folio_nr_pages(folio); @@ -1040,20 +1036,7 @@ static void __pagevec_lru_add_fn(struct folio *folio, struct lruvec *lruvec) */ void __pagevec_lru_add(struct pagevec *pvec) { - int i; - struct lruvec *lruvec = NULL; - unsigned long flags = 0; - - for (i = 0; i < pagevec_count(pvec); i++) { - struct folio *folio = page_folio(pvec->pages[i]); - - lruvec = folio_lruvec_relock_irqsave(folio, lruvec, &flags); - __pagevec_lru_add_fn(folio, lruvec); - } - if (lruvec) - unlock_page_lruvec_irqrestore(lruvec, flags); - release_pages(pvec->pages, pvec->nr); - pagevec_reinit(pvec); + pagevec_lru_move_fn(pvec, __pagevec_lru_add_fn); } /** diff --git a/mm/vmscan.c b/mm/vmscan.c index 902d36ec91a3..7cff2f748df8 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -4667,18 +4667,17 @@ void check_move_unevictable_pages(struct pagevec *pvec) nr_pages = thp_nr_pages(page); pgscanned += nr_pages; - /* block memcg migration during page moving between lru */ - if (!TestClearPageLRU(page)) + lruvec = folio_lruvec_relock_irq(folio, lruvec); + + if (!PageLRU(page) || !PageUnevictable(page)) continue; - lruvec = folio_lruvec_relock_irq(folio, lruvec); - if (page_evictable(page) && PageUnevictable(page)) { + if (page_evictable(page)) { del_page_from_lru_list(page, lruvec); ClearPageUnevictable(page); add_page_to_lru_list(page, lruvec); pgrescued += nr_pages; } - SetPageLRU(page); } if (lruvec) { -- 2.11.0