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=-9.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 A5DF3C5ACC1 for ; Tue, 17 Mar 2020 05:42:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7B22120736 for ; Tue, 17 Mar 2020 05:42:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Va/f0gGE" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726587AbgCQFm2 (ORCPT ); Tue, 17 Mar 2020 01:42:28 -0400 Received: from mail-pg1-f193.google.com ([209.85.215.193]:36763 "EHLO mail-pg1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726066AbgCQFm0 (ORCPT ); Tue, 17 Mar 2020 01:42:26 -0400 Received: by mail-pg1-f193.google.com with SMTP id z72so1250792pgz.3 for ; Mon, 16 Mar 2020 22:42:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=2X37snKsWsbjnSC5G8JKDN8U4XxTo8mCwhpNzWhIZ/g=; b=Va/f0gGE31wRD/TpGDskcGX2Bef2+hsg3s3UovewxNs+hxNqvyVU5KGLQw3dr5ThQO 7fzmRVnDqkMUog4CZ9FAIBeHkKqg2Q1Frh+sYHmLspg5JB2MGLV4UgwE0eQ80S5f2dKW ZV/dJ/LIHbWXpoivteZR8rbN/cUhoheqoNq8bn4CbNg72ZZjcAHlL2Src5W6j62AUWiN dHfDYzcSQz2j8Nxz8F2PckPsowOUf+G/M6VPH531/csFrfA77H7cS8nOEJjM0gesiVW0 XrWsRkV3MwgYK0VADbCHO9UBqPFCnM0df/HrTvxQrXLqHZKvlk2eAbQ5sRI+3xCv5P0L lo3Q== 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; bh=2X37snKsWsbjnSC5G8JKDN8U4XxTo8mCwhpNzWhIZ/g=; b=DATHk4hthfwocup7vKN5foHZld8kNCa7Ux5hqADcy31XmzQs+MxjoPjsuPPEMGbjDG DqH1HtMYs5ZjYTlEX6uq/cFOD3jTLYrssYNznq7Le0NjM45y3mltfTEyCMjw0JPJ/wkc TPTDIesgJmhAYKNAoDiPsSX8O8bE2sa/bPjjxmWONp2UKuO73GPj3/fz6AKjvZEGDx5N 1T8UQ29Hs20MY9OnmvNSKTmMziRCi7NZghAUMmNMh+DCqu62Bm6uyGm+Wicvyywd5ykz Ixo3ZAcH5/X0kNPn3Lf92fQWAN9oKafgqTPtclGhcOcajipmig1aRrW5wozIYdtDREAY xmCA== X-Gm-Message-State: ANhLgQ03UDGJ2OUIcqBqBX5auD2UMi6A88nD/sfCyi0BxWxzz8sPA9wx lSkCBXdsbS2ci9bMkYwADKs= X-Google-Smtp-Source: ADFU+vtRuRKjW6rHDlPpf7QQve7i+QUC87wnc3hjTi1s21hkuBBIjKnImzczMw4JfQMWJdJjgTmz/Q== X-Received: by 2002:a62:a116:: with SMTP id b22mr3541272pff.122.1584423745852; Mon, 16 Mar 2020 22:42:25 -0700 (PDT) Received: from localhost.localdomain ([114.206.198.176]) by smtp.gmail.com with ESMTPSA id i21sm1141757pgn.5.2020.03.16.22.42.22 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Mon, 16 Mar 2020 22:42:25 -0700 (PDT) From: js1304@gmail.com X-Google-Original-From: iamjoonsoo.kim@lge.com To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Johannes Weiner , Michal Hocko , Hugh Dickins , Minchan Kim , Vlastimil Babka , Mel Gorman , kernel-team@lge.com, Joonsoo Kim Subject: [PATCH v3 6/9] mm/workingset: handle the page without memcg Date: Tue, 17 Mar 2020 14:41:54 +0900 Message-Id: <1584423717-3440-7-git-send-email-iamjoonsoo.kim@lge.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1584423717-3440-1-git-send-email-iamjoonsoo.kim@lge.com> References: <1584423717-3440-1-git-send-email-iamjoonsoo.kim@lge.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Joonsoo Kim When implementing workingset detection for anonymous page, I found some swapcache pages with NULL memcg. From the code reading, I found two reasons. One is the case that swap-in readahead happens. The other is the corner case related to the shmem cache. These two problems should be fixed, but, it's not straight-forward to fix. For example, when swap-off, all swapped-out pages are read into swapcache. In this case, who's the owner of the swapcache page? Since this problem doesn't look trivial, I decide to leave the issue and handles this corner case on the place where the error occurs. Signed-off-by: Joonsoo Kim --- mm/workingset.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/mm/workingset.c b/mm/workingset.c index a9f474a..8d2e83a 100644 --- a/mm/workingset.c +++ b/mm/workingset.c @@ -257,6 +257,10 @@ void *workingset_eviction(struct page *page, struct mem_cgroup *target_memcg) VM_BUG_ON_PAGE(page_count(page), page); VM_BUG_ON_PAGE(!PageLocked(page), page); + /* page_memcg() can be NULL if swap-in readahead happens */ + if (!page_memcg(page)) + return NULL; + advance_inactive_age(page_memcg(page), pgdat, is_file); lruvec = mem_cgroup_lruvec(target_memcg, pgdat); -- 2.7.4