From patchwork Wed Feb 17 20:41:35 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tim Chen X-Patchwork-Id: 12092441 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, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 C726AC433E0 for ; Wed, 17 Feb 2021 21:41:58 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 356CC64E5F for ; Wed, 17 Feb 2021 21:41:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 356CC64E5F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 294B48D0002; Wed, 17 Feb 2021 16:41:57 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 21B588D0001; Wed, 17 Feb 2021 16:41:57 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 10A438D0002; Wed, 17 Feb 2021 16:41:57 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0193.hostedemail.com [216.40.44.193]) by kanga.kvack.org (Postfix) with ESMTP id EE4D08D0001 for ; Wed, 17 Feb 2021 16:41:56 -0500 (EST) Received: from smtpin05.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id BD64F18485042 for ; Wed, 17 Feb 2021 21:41:56 +0000 (UTC) X-FDA: 77829082632.05.0733372 Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by imf09.hostedemail.com (Postfix) with ESMTP id 29D82600249C for ; Wed, 17 Feb 2021 21:41:52 +0000 (UTC) IronPort-SDR: zjS6ll4qNx/RC0JrekmY24E9LdHPHOQzCyYkxAAl7xjtjFMjoru/S/AhVmeyOARbbKBLaMf8tZ ilgxk0ESPiSg== X-IronPort-AV: E=McAfee;i="6000,8403,9898"; a="182538758" X-IronPort-AV: E=Sophos;i="5.81,185,1610438400"; d="scan'208";a="182538758" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Feb 2021 13:41:55 -0800 IronPort-SDR: 9Hq9KtM7miCiBDav7pvUqi5nyuDRGHZpaD7BBiidOVHP9uYoSc5++KYkN6vXYDuFE8r3evNcC+ tofPWpXB6Xqw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.81,185,1610438400"; d="scan'208";a="401430712" Received: from skl-02.jf.intel.com ([10.54.74.28]) by orsmga007.jf.intel.com with ESMTP; 17 Feb 2021 13:41:55 -0800 From: Tim Chen To: Andrew Morton , Johannes Weiner , Michal Hocko , Vladimir Davydov Cc: Tim Chen , Dave Hansen , Ying Huang , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 2/3] mm: Force update of mem cgroup soft limit tree on usage excess Date: Wed, 17 Feb 2021 12:41:35 -0800 Message-Id: <06f1f92f1f7d4e57c4e20c97f435252c16c60a27.1613584277.git.tim.c.chen@linux.intel.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: References: MIME-Version: 1.0 X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 29D82600249C X-Stat-Signature: 6ay7ip3wn9esmis5xqyybhn6ktqeirim Received-SPF: none (linux.intel.com>: No applicable sender policy available) receiver=imf09; identity=mailfrom; envelope-from=""; helo=mga14.intel.com; client-ip=192.55.52.115 X-HE-DKIM-Result: none/none X-HE-Tag: 1613598112-27128 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: To rate limit updates to the mem cgroup soft limit tree, we only perform updates every SOFTLIMIT_EVENTS_TARGET (defined as 1024) memory events. However, this sampling based updates may miss a critical update: i.e. when the mem cgroup first exceeded its limit but it was not on the soft limit tree. It should be on the tree at that point so it could be subjected to soft limit page reclaim. If the mem cgroup had few memory events compared with other mem cgroups, we may not update it and place in on the mem cgroup soft limit tree for many memory events. And this mem cgroup excess usage could creep up and the mem cgroup could be hidden from the soft limit page reclaim for a long time. Fix this issue by forcing an update to the mem cgroup soft limit tree if a mem cgroup has exceeded its memory soft limit but it is not on the mem cgroup soft limit tree. Reviewed-by: Ying Huang Signed-off-by: Tim Chen Reported-by: kernel test robot --- mm/memcontrol.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index a51bf90732cb..d72449eeb85a 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -985,15 +985,22 @@ static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg, */ static void memcg_check_events(struct mem_cgroup *memcg, struct page *page) { + struct mem_cgroup_per_node *mz; + bool force_update = false; + + mz = mem_cgroup_nodeinfo(memcg, page_to_nid(page)); + if (mz && !mz->on_tree && soft_limit_excess(mz->memcg) > 0) + force_update = true; + /* threshold event is triggered in finer grain than soft limit */ - if (unlikely(mem_cgroup_event_ratelimit(memcg, + if (unlikely((force_update) || mem_cgroup_event_ratelimit(memcg, MEM_CGROUP_TARGET_THRESH))) { bool do_softlimit; do_softlimit = mem_cgroup_event_ratelimit(memcg, MEM_CGROUP_TARGET_SOFTLIMIT); mem_cgroup_threshold(memcg); - if (unlikely(do_softlimit)) + if (unlikely((force_update) || do_softlimit)) mem_cgroup_update_tree(memcg, page); } }