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=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 E21A4C2D0A3 for ; Fri, 6 Nov 2020 08:51:22 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 3E8E9206DC for ; Fri, 6 Nov 2020 08:51:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3E8E9206DC Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 4D8746B005C; Fri, 6 Nov 2020 03:51:19 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 4619F6B005D; Fri, 6 Nov 2020 03:51:19 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 350606B0068; Fri, 6 Nov 2020 03:51:19 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0249.hostedemail.com [216.40.44.249]) by kanga.kvack.org (Postfix) with ESMTP id F385B6B005C for ; Fri, 6 Nov 2020 03:51:18 -0500 (EST) Received: from smtpin08.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id A37F645B3 for ; Fri, 6 Nov 2020 08:51:18 +0000 (UTC) X-FDA: 77453374236.08.mass11_0403b08272d1 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin08.hostedemail.com (Postfix) with ESMTP id 82AD41819E764 for ; Fri, 6 Nov 2020 08:51:18 +0000 (UTC) X-HE-Tag: mass11_0403b08272d1 X-Filterd-Recvd-Size: 3719 Received: from out30-54.freemail.mail.aliyun.com (out30-54.freemail.mail.aliyun.com [115.124.30.54]) by imf02.hostedemail.com (Postfix) with ESMTP for ; Fri, 6 Nov 2020 08:51:15 +0000 (UTC) X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R561e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=alimailimapcm10staff010182156082;MF=zhongjiang-ali@linux.alibaba.com;NM=1;PH=DS;RN=4;SR=0;TI=SMTPD_---0UEPUE3w_1604652665; Received: from localhost(mailfrom:zhongjiang-ali@linux.alibaba.com fp:SMTPD_---0UEPUE3w_1604652665) by smtp.aliyun-inc.com(127.0.0.1); Fri, 06 Nov 2020 16:51:10 +0800 From: zhongjiang-ali To: hannes@cmpxchg.org, mhocko@kernel.org, akpm@linux-foundation.org Cc: linux-mm@kvack.org Subject: [PATCH] memcg, oom: check memcg margin for parallel oom Date: Fri, 6 Nov 2020 16:51:05 +0800 Message-Id: <1604652665-13640-1-git-send-email-zhongjiang-ali@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 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: Yafang Shao Memcg oom killer invocation is synchronized by the global oom_lock and tasks are sleeping on the lock while somebody is selecting the victim or potentially race with the oom_reaper is releasing the victim's memory. This can result in a pointless oom killer invocation because a waiter might be racing with the oom_reaper P1 oom_reaper P2 oom_reap_task mutex_lock(oom_lock) out_of_memory # no victim because we have one already __oom_reap_task_mm mute_unlock(oom_lock) mutex_lock(oom_lock) set MMF_OOM_SKIP select_bad_process # finds a new victim The page allocator prevents from this race by trying to allocate after the lock can be acquired (in __alloc_pages_may_oom) which acts as a last minute check. Moreover page allocator simply doesn't block on the oom_lock and simply retries the whole reclaim process. Memcg oom killer should do the last minute check as well. Call mem_cgroup_margin to do that. Trylock on the oom_lock could be done as well but this doesn't seem to be necessary at this stage. [mhocko@kernel.org: commit log] Suggested-by: Michal Hocko Signed-off-by: Yafang Shao Signed-off-by: Andrew Morton Acked-by: Michal Hocko Acked-by: Chris Down Cc: Tetsuo Handa Cc: David Rientjes Cc: Johannes Weiner Link: http://lkml.kernel.org/r/1594735034-19190-1-git-send-email-laoar.shao@gmail.com Signed-off-by: Linus Torvalds Signed-off-by: zhongjiang-ali --- mm/memcontrol.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index b30a52d..369d9e1 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1663,15 +1663,21 @@ static bool mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask, .gfp_mask = gfp_mask, .order = order, }; - bool ret; + bool ret = true; if (mutex_lock_killable(&oom_lock)) return true; + + if (mem_cgroup_margin(memcg) >= (1 << order)) + goto unlock; + /* * A few threads which were not waiting at mutex_lock_killable() can * fail to bail out. Therefore, check again after holding oom_lock. */ ret = should_force_charge() || out_of_memory(&oc); + +unlock: mutex_unlock(&oom_lock); return ret; } -- 1.8.3.1