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 2851FC5ACC2 for ; Tue, 17 Mar 2020 05:42:28 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id DB8262071C for ; Tue, 17 Mar 2020 05:42:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Va/f0gGE" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DB8262071C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 9109D6B000D; Tue, 17 Mar 2020 01:42:27 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 899806B000E; Tue, 17 Mar 2020 01:42:27 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 788EE6B0010; Tue, 17 Mar 2020 01:42:27 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0092.hostedemail.com [216.40.44.92]) by kanga.kvack.org (Postfix) with ESMTP id 617A86B000D for ; Tue, 17 Mar 2020 01:42:27 -0400 (EDT) Received: from smtpin10.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 4EFEF8248076 for ; Tue, 17 Mar 2020 05:42:27 +0000 (UTC) X-FDA: 76603759134.10.tax57_6cb42734e2b58 X-HE-Tag: tax57_6cb42734e2b58 X-Filterd-Recvd-Size: 4408 Received: from mail-pg1-f193.google.com (mail-pg1-f193.google.com [209.85.215.193]) by imf19.hostedemail.com (Postfix) with ESMTP for ; Tue, 17 Mar 2020 05:42:26 +0000 (UTC) Received: by mail-pg1-f193.google.com with SMTP id 7so11104214pgr.2 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=lJag64XxNPS4856eU5B1Mm3XC9zLAJnQaRvqkjeP+H55GYYA74GFhN/3nSllRuv7h5 kOHh2UyoYrKdM95ixWk1DXkx0ueoh0+4GNpAWm2yO0h5ZubmFBU0gJktkfQvth1HGRTc G/ISi4KSfUj5QMIiq+NpqPaft0/SyI8kMWMJusl8SB800DnvCNOyuI+BCWw9K0qkkgMr xCJTOMBf5bJGxRUj1jssCuKDk8lNJSxcT+rDO8VmE/LJUlJQxap02006OiG8q+l7v7Nl odfnegdU4SLzLe9pw8OOgGcdJgkGmwfAJQA4+/s4HDEjI49wuHsJ3jz/x35gPGgO99SW MfVQ== X-Gm-Message-State: ANhLgQ0GjqFKXkab+coq9FbFkEAmuYPtwUH7sggIBGE/ZfvyrIQeIjAr 9H6x31ntbsq6U9uAPy/Zblw= 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> X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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