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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 E3FB4C433EF for ; Mon, 13 Sep 2021 08:53:38 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 8CFA360FBF for ; Mon, 13 Sep 2021 08:53:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 8CFA360FBF Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 1D7AF900002; Mon, 13 Sep 2021 04:53:38 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 1864F6B0072; Mon, 13 Sep 2021 04:53:38 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 075B7900002; Mon, 13 Sep 2021 04:53:38 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0228.hostedemail.com [216.40.44.228]) by kanga.kvack.org (Postfix) with ESMTP id EAF896B0071 for ; Mon, 13 Sep 2021 04:53:37 -0400 (EDT) Received: from smtpin01.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 9E216181AEF3E for ; Mon, 13 Sep 2021 08:53:37 +0000 (UTC) X-FDA: 78581936874.01.1E1E341 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by imf25.hostedemail.com (Postfix) with ESMTP id 33F16B00008E for ; Mon, 13 Sep 2021 08:53:37 +0000 (UTC) Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id 2BD0B1FFAB; Mon, 13 Sep 2021 08:53:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1631523216; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=kchB+aw0FiEHbBgAGvT8V7qxriNJ47RlDUOFmHHFsR8=; b=kGFs+4yihN3fLKCge3xceliBWYVrbZxUw+0zsqAVcpn5mgLH/8I1UfL/abne0cLcIy5BfQ yKP5rIR4r7OfrZo/Xkn8Xzn3z6WA/qAVONP+h+kArUvhUxk8NrP4LW4K8CNZ0VD72+YMAX HXBEC49PkTTooA+LPItgSLJerNg1ol0= Received: from suse.cz (unknown [10.100.201.86]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id DBC99A3B93; Mon, 13 Sep 2021 08:53:35 +0000 (UTC) Date: Mon, 13 Sep 2021 10:53:35 +0200 From: Michal Hocko To: Vasily Averin Cc: Johannes Weiner , Vladimir Davydov , Andrew Morton , Tetsuo Handa , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH memcg] memcg: prohibit unconditional exceeding the limit of dying tasks Message-ID: References: <5b06a490-55bc-a6a0-6c85-690254f86fad@virtuozzo.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5b06a490-55bc-a6a0-6c85-690254f86fad@virtuozzo.com> X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 33F16B00008E X-Stat-Signature: 9kkpjkgmf5c5eabo5ieyybwtksg1eb6a Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=suse.com header.s=susede1 header.b=kGFs+4yi; spf=pass (imf25.hostedemail.com: domain of mhocko@suse.com designates 195.135.220.29 as permitted sender) smtp.mailfrom=mhocko@suse.com; dmarc=pass (policy=quarantine) header.from=suse.com X-HE-Tag: 1631523217-237524 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 Fri 10-09-21 15:39:28, Vasily Averin wrote: > The kernel currently allows dying tasks to exceed the memcg limits. > The allocation is expected to be the last one and the occupied memory > will be freed soon. > This is not always true because it can be part of the huge vmalloc > allocation. Allowed once, they will repeat over and over again. > Moreover lifetime of the allocated object can differ from > In addition the lifetime of the dying task. > Multiple such allocations running concurrently can not only overuse > the memcg limit, but can lead to a global out of memory and, > in the worst case, cause the host to panic. > > Signed-off-by: Vasily Averin > --- > mm/memcontrol.c | 23 +++++------------------ > 1 file changed, 5 insertions(+), 18 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 389b5766e74f..67195fcfbddf 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -1834,6 +1834,9 @@ static enum oom_status mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int > return OOM_ASYNC; > } > > + if (should_force_charge()) > + return OOM_SKIPPED; mem_cgroup_out_of_memory already check for the bypass, now you are duplicating that check with a different answer to the caller. This is really messy. One of the two has to go away. -- Michal Hocko SUSE Labs