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 99F09C433FE for ; Tue, 19 Oct 2021 06:43:07 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 09F216115B for ; Tue, 19 Oct 2021 06:43:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 09F216115B 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 79B956B006C; Tue, 19 Oct 2021 02:43:06 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 724016B0071; Tue, 19 Oct 2021 02:43:06 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5EBAA900002; Tue, 19 Oct 2021 02:43:06 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0242.hostedemail.com [216.40.44.242]) by kanga.kvack.org (Postfix) with ESMTP id 4C07B6B006C for ; Tue, 19 Oct 2021 02:43:06 -0400 (EDT) Received: from smtpin28.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 0ABB029326 for ; Tue, 19 Oct 2021 06:43:06 +0000 (UTC) X-FDA: 78712244772.28.588948F Received: from relay.sw.ru (relay.sw.ru [185.231.240.75]) by imf29.hostedemail.com (Postfix) with ESMTP id 37CCF9000254 for ; Tue, 19 Oct 2021 06:43:03 +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=7OMO0M/WVTVgdjf54DbVIyAnXJtSdE0/PzhJZH94xwI=; b=fPQL2wCo4GhLrjLrD anIW7ziZKa2yTrj1Yv+V3pi/G++isnPb2GTrpeZlWODv2dfS13Hse6Ohml5LOq9tSMfcC4BhU3xWz Lq1x991hoRqY/xa4bB6VwdX8WbAEeq4qDFq5WNm6fbE3KcEZblf99MLXtfUce9BjcqcZuVKQ6hETI =; Received: from [172.29.1.17] by relay.sw.ru with esmtp (Exim 4.94.2) (envelope-from ) id 1mcipv-006Qte-Ql; Tue, 19 Oct 2021 09:42:59 +0300 Subject: Re: [PATCH memcg 0/1] false global OOM triggered by memcg-limited task To: Shakeel Butt Cc: Michal Hocko , Johannes Weiner , Vladimir Davydov , Andrew Morton , Roman Gushchin , Uladzislau Rezki , Vlastimil Babka , Mel Gorman , Cgroups , Linux MM , LKML , kernel@openvz.org References: <9d10df01-0127-fb40-81c3-cc53c9733c3e@virtuozzo.com> <6b751abe-aa52-d1d8-2631-ec471975cc3a@virtuozzo.com> <27dc0c49-a0d6-875b-49c6-0ef5c0cc3ac8@virtuozzo.com> <153f7aa6-39ef-f064-8745-a9489e088239@virtuozzo.com> From: Vasily Averin Message-ID: <25120323-d222-cc5e-fe08-6471bce13bd6@virtuozzo.com> Date: Tue, 19 Oct 2021 09:42:38 +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: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 37CCF9000254 X-Stat-Signature: 39w4fm4iwoaubygegmz9cx7ddfrhmx7p Authentication-Results: imf29.hostedemail.com; dkim=pass header.d=virtuozzo.com header.s=relay header.b=fPQL2wCo; dmarc=pass (policy=quarantine) header.from=virtuozzo.com; spf=pass (imf29.hostedemail.com: domain of vvs@virtuozzo.com designates 185.231.240.75 as permitted sender) smtp.mailfrom=vvs@virtuozzo.com X-Rspamd-Server: rspam02 X-HE-Tag: 1634625783-763227 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 19.10.2021 08:33, Shakeel Butt wrote: > On Mon, Oct 18, 2021 at 11:52 AM Vasily Averin wrote: >> >> On 18.10.2021 18:07, Shakeel Butt wrote: >>> On Mon, Oct 18, 2021 at 5:27 AM Michal Hocko wrote: >>>> >>>> [restore the cc list] >>>> >>>> On Mon 18-10-21 15:14:26, Vasily Averin wrote: >>>>> On 18.10.2021 14:53, Michal Hocko wrote: >>>>>> On Mon 18-10-21 13:05:35, Vasily Averin wrote: >>>>>>> On 18.10.2021 12:04, Michal Hocko wrote: >>>>>>> Here we call try_charge_memcg() that return success and approve the allocation, >>>>>>> however then we hit into kmem limit and fail the allocation. >>>>>> >>>>>> Just to make sure I understand this would be for the v1 kmem explicit >>>>>> limit, correct? >>>>> >>>>> yes, I mean this limit. >>>> >>>> OK, thanks for the clarification. This is a known problem. Have a look >>>> at I think we consider that one to 0158115f702b ("memcg, kmem: deprecate >>>> kmem.limit_in_bytes"). We are reporting the deprecated and to-be removed >>>> status since 2019 without any actual report sugested by the kernel >>>> message. Maybe we should try and remove it and see whether that prompts >>>> some pushback. >>> >>> Yes, I think now should be the right time to take the next step for >>> deprecation of kmem limits: >>> https://lore.kernel.org/all/20201118175726.2453120-1-shakeelb@google.com/ >> >> Are you going to push it to stable kernels too? > > Not really. Is there a reason I should? More exposure to catch breakage? There is a problem: kmem limit can trigger fake global OOM. To fix it in upstream you can remove kmem controller. However how to handle this problem in stable and LTS kernels? My current patch resolves the problem too, and it can be backported. However I afraid nobody will do it if teh patch will not be approved in upsteam. Thank you, Vasily Averin