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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E71A6C43219 for ; Mon, 1 Nov 2021 08:06:03 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 7F39961100 for ; Mon, 1 Nov 2021 08:06:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 7F39961100 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id CDFFC940009; Mon, 1 Nov 2021 04:06:02 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C8E2B940008; Mon, 1 Nov 2021 04:06:02 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B7D35940009; Mon, 1 Nov 2021 04:06:02 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0044.hostedemail.com [216.40.44.44]) by kanga.kvack.org (Postfix) with ESMTP id A51F7940008 for ; Mon, 1 Nov 2021 04:06:02 -0400 (EDT) Received: from smtpin15.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 54E7C1816E80A for ; Mon, 1 Nov 2021 08:06:02 +0000 (UTC) X-FDA: 78759628164.15.CCEADCF Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by imf11.hostedemail.com (Postfix) with ESMTP id 695FEF0000A8 for ; Mon, 1 Nov 2021 08:06:01 +0000 (UTC) Received: from dggemv703-chm.china.huawei.com (unknown [172.30.72.55]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4HjQTL1yDDzcb0S; Mon, 1 Nov 2021 16:01:10 +0800 (CST) Received: from dggpeml500005.china.huawei.com (7.185.36.59) by dggemv703-chm.china.huawei.com (10.3.19.46) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.15; Mon, 1 Nov 2021 16:05:51 +0800 Received: from [10.174.178.155] (10.174.178.155) by dggpeml500005.china.huawei.com (7.185.36.59) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.2308.15; Mon, 1 Nov 2021 16:05:50 +0800 From: Yongqiang Liu To: CC: , , , , "Wangkefeng (OS Kernel Lab)" Subject: [QUESTION] oom killed the key system process triggered by a bad process alloc memory with MAP_LOCKED Message-ID: Date: Mon, 1 Nov 2021 16:05:50 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.8.0 MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8"; format=flowed X-Originating-IP: [10.174.178.155] X-ClientProxiedBy: dggeme702-chm.china.huawei.com (10.1.199.98) To dggpeml500005.china.huawei.com (7.185.36.59) X-CFilter-Loop: Reflected Authentication-Results: imf11.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=huawei.com; spf=pass (imf11.hostedemail.com: domain of liuyongqiang13@huawei.com designates 45.249.212.187 as permitted sender) smtp.mailfrom=liuyongqiang13@huawei.com X-Stat-Signature: 8grbhiw5rgb5pafcbgbmmz7frquyht7q X-Rspamd-Queue-Id: 695FEF0000A8 X-Rspamd-Server: rspam01 X-HE-Tag: 1635753961-971 Content-Transfer-Encoding: quoted-printable 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: Hi, I was just wondering the process of=C2=A0 the patch "oom reaper: handle=20 mlocked pages". links: https://lore.kernel.org/linux-mm/1454505240-23446-3-git-send-email-mhocko= @kernel.org/ https://lore.kernel.org/linux-mm/20160223132157.GD14178@dhcp22.suse.cz/ In linux master, we found that when we start a process and alloc large=20 memory with MAP_LOCKED, the oom will triggered and kill some system=20 process such as sshd ,rsyslog etc. ... [=C2=A0=C2=A0 45.110665] Out of memory: Killed process 2551 (oom)=20 total-vm:1035324kB, anon-rss:1028196kB, file-rss:704kB, shmem-rss:0kB,=20 UID:0 pgtables:2056kB oom_score_adj:1000 [=C2=A0=C2=A0 45.115303] Out of memory: Killed process 2554 (oom)=20 total-vm:1025084kB, anon-rss:1015596kB, file-rss:388kB, shmem-rss:0kB,=20 UID:0 pgtables:2032kB oom_score_adj:1000 [=C2=A0=C2=A0 45.115685] Out of memory: Killed process 2553 (oom)=20 total-vm:953404kB, anon-rss:947748kB, file-rss:388kB, shmem-rss:0kB,=20 UID:0 pgtables:1896kB oom_score_adj:1000 [=C2=A0=C2=A0 45.116031] Out of memory: Killed process 2552 (oom)=20 total-vm:789564kB, anon-rss:783272kB, file-rss:388kB, shmem-rss:0kB,=20 UID:0 pgtables:1576kB oom_score_adj:1000 [=C2=A0=C2=A0 45.117199] Out of memory: Killed process 2523 (sshd)=20 total-vm:77052kB, anon-rss:804kB, file-rss:4672kB, shmem-rss:4kB, UID:0=20 pgtables:196kB oom_score_adj:0 [=C2=A0=C2=A0 45.120936] Out of memory: Killed process 2526 (bash)=20 total-vm:17792kB, anon-rss:1180kB, file-rss:2868kB, shmem-rss:0kB, UID:0=20 pgtables:76kB oom_score_adj:0 ... the process demo is: ... #define ALLOC_SIZE (10 * 1024 * 1024) while (1) { =C2=A0=C2=A0=C2=A0 addr =3D mmap(NULL, ALLOC_SIZE, PROT_READ | PROT_WRIT= E, MAP_PRIVATE |=20 MAP_ANONYMOUS | MAP_LOCKED, -1, 0); =C2=A0=C2=A0=C2=A0 if (addr !=3D MAP_FAILED) =C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2=A0 memset(addr, 1, ALLOC_SIZE); } ... And we found that when the oom_reaper is done but the memory is still hig= h: [=C2=A0=C2=A0 45.115685] Out of memory: Killed process 2553 (oom)=20 total-vm:953404kB, anon-rss:947748kB, file-rss:388kB, shmem-rss:0kB,=20 UID:0 pgtables:1896kB oom_score_adj:1000 [=C2=A0=C2=A0 45.115739] oom_reaper: reaped process 2553 (oom), now=20 anon-rss:947708kB, file-rss:0kB, shmem-rss:0kB This is because the bad proccess which recieved SIGKILL is unlocking the=20 mem to exit which needs more time. And the next oom is triggered to kill=20 the other system process. Kind regards, Yongqiang Liu