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 3A0F3C433FE for ; Tue, 5 Oct 2021 14:01:12 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D132E6126A for ; Tue, 5 Oct 2021 14:01:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org D132E6126A Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=virtuozzo.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 725B16B006C; Tue, 5 Oct 2021 10:01:11 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 6D4B86B0071; Tue, 5 Oct 2021 10:01:11 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5C3D6900002; Tue, 5 Oct 2021 10:01:11 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0082.hostedemail.com [216.40.44.82]) by kanga.kvack.org (Postfix) with ESMTP id 49CB56B006C for ; Tue, 5 Oct 2021 10:01:11 -0400 (EDT) Received: from smtpin13.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id EADCB82499B9 for ; Tue, 5 Oct 2021 14:01:10 +0000 (UTC) X-FDA: 78662545500.13.4903566 Received: from relay.sw.ru (relay.sw.ru [185.231.240.75]) by imf21.hostedemail.com (Postfix) with ESMTP id 345C3D03A388 for ; Tue, 5 Oct 2021 14:00:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=virtuozzo.com; s=relay; h=Content-Type:MIME-Version:Date:Message-ID:From: Subject; bh=Ed1xsp8lTrCrW27f1J4vH57YUUHw0q5d5pOknhx3OhI=; b=dlg9oxUUL9ON2P7NI FPotPplwDm0pN9yRtW6uR6cImMJygenILBxuPbXKwHqwkrR4Xsm7PM70jOo1HQjb2RHaPSRAf8sNN 43yHyfSpf5DwKO2Vlo3GxDZ1spky8JiojDNWL2JimTvGua0MPzIGIEIvEsmMJTyevyQJZawJhUsLI =; Received: from [10.93.0.56] by relay.sw.ru with esmtp (Exim 4.94.2) (envelope-from ) id 1mXkzF-0054Yv-SG; Tue, 05 Oct 2021 17:00:05 +0300 Subject: Re: [PATCH mm v2] vmalloc: back off when the current task is OOM-killed From: Vasily Averin To: Michal Hocko Cc: Johannes Weiner , Vladimir Davydov , Andrew Morton , Tetsuo Handa , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel@openvz.org References: <83efc664-3a65-2adb-d7c4-2885784cf109@virtuozzo.com> Message-ID: Date: Tue, 5 Oct 2021 17:00:05 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 MIME-Version: 1.0 In-Reply-To: <83efc664-3a65-2adb-d7c4-2885784cf109@virtuozzo.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 345C3D03A388 X-Stat-Signature: soqo9gonqxxde9dmbe5n84niisnf1eiz Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=virtuozzo.com header.s=relay header.b=dlg9oxUU; dmarc=pass (policy=quarantine) header.from=virtuozzo.com; spf=pass (imf21.hostedemail.com: domain of vvs@virtuozzo.com designates 185.231.240.75 as permitted sender) smtp.mailfrom=vvs@virtuozzo.com X-HE-Tag: 1633442410-828070 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: On 10/5/21 4:52 PM, Vasily Averin wrote: > Huge vmalloc allocation on heavy loaded node can lead to a global > memory shortage. Task called vmalloc can have worst badness and > be selected by OOM-killer, however taken fatal signal does not > interrupt allocation cycle. Vmalloc repeat page allocaions > again and again, exacerbating the crisis and consuming the memory > freed up by another killed tasks. > > After a successful completion of the allocation procedure, a fatal > signal will be processed and task will be destroyed finally. > However it may not release the consumed memory, since the allocated > object may have a lifetime unrelated to the completed task. > In the worst case, this can lead to the host will panic > due to "Out of memory and no killable processes..." > > This patch allows OOM-killer to break vmalloc cycle, makes OOM more > effective and avoid host panic. It does not check oom condition directly, > however, and breaks page allocation cycle when fatal signal was received. > > This may trigger some hidden problems, when caller does not handle > vmalloc failures, or when rollaback after failed vmalloc calls own > vmallocs inside. However all of these scenarios are incorrect: > vmalloc does not guarantee successful allocation, it has never been called > with __GFP_NOFAIL and threfore either should not be used for any rollbacks > or should handle such errors correctly and not lead to critical > failures. I briefly checked this patch together with v3 memcg: prohibit unconditional exceeding the limit of dying tasks over v5.15-rc4. I executed LTP on host, all oom, cgroup and memcg tests was successfully finished. and then experimented with memcg limited LXC containers. I did not noticed any troubles on my test node. Thank you, Vasily Averin