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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8A5E9C433EF for ; Wed, 1 Jun 2022 09:32:28 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 219876B00A4; Wed, 1 Jun 2022 05:32:28 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 1C60D6B00A5; Wed, 1 Jun 2022 05:32:28 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0B3016B00A6; Wed, 1 Jun 2022 05:32:28 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id F1ADD6B00A4 for ; Wed, 1 Jun 2022 05:32:27 -0400 (EDT) Received: from smtpin29.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id C057331816 for ; Wed, 1 Jun 2022 09:32:27 +0000 (UTC) X-FDA: 79529151534.29.FB782F4 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by imf31.hostedemail.com (Postfix) with ESMTP id 6617E2006F for ; Wed, 1 Jun 2022 09:31:46 +0000 (UTC) Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id 3667F1F948; Wed, 1 Jun 2022 09:32:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1654075946; 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=lTCJZ2bUJ3/puiljHjqguHJc4A3/gQf69h4JgyxoJlI=; b=gFUeOb8srA+PPm1aBMyMYbScxooALNkP7f+l3huThUfo2iW4yr72417wNGGyK/OlXpcPL/ CZD6KvjeCnXkleDBG3qgI6oFqj3++xOy6Su3SsLn8pfvSSd964/MDyxteGjPtYE2YXJx+/ Kf1LS61x+N8X6OviXR2U8LNH8VOq2v0= 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 F32D42C141; Wed, 1 Jun 2022 09:32:25 +0000 (UTC) Date: Wed, 1 Jun 2022 11:32:25 +0200 From: Michal Hocko To: Michal =?iso-8859-1?Q?Koutn=FD?= Cc: Vasily Averin , Andrew Morton , kernel@openvz.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Shakeel Butt , Roman Gushchin , Vlastimil Babka , Muchun Song , cgroups@vger.kernel.org Subject: Re: [PATCH mm v3 0/9] memcg: accounting for objects allocated by mkdir cgroup Message-ID: References: <06505918-3b8a-0ad5-5951-89ecb510138e@openvz.org> <3e1d6eab-57c7-ba3d-67e1-c45aa0dfa2ab@openvz.org> <3a1d8554-755f-7976-1e00-a0e7fb62c86e@openvz.org> <118bcb39-1281-0d1d-b163-3f6bcc99c3e2@openvz.org> <20220601091543.GA21320@blackbody.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220601091543.GA21320@blackbody.suse.cz> X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 6617E2006F Authentication-Results: imf31.hostedemail.com; dkim=pass header.d=suse.com header.s=susede1 header.b=gFUeOb8s; dmarc=pass (policy=quarantine) header.from=suse.com; spf=pass (imf31.hostedemail.com: domain of mhocko@suse.com designates 195.135.220.29 as permitted sender) smtp.mailfrom=mhocko@suse.com X-Stat-Signature: 3o4bcce58cwrgor9tctxic4xaejfpe6n X-Rspam-User: X-HE-Tag: 1654075906-507586 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 Wed 01-06-22 11:15:43, Michal Koutny wrote: > On Wed, Jun 01, 2022 at 06:43:27AM +0300, Vasily Averin wrote: > > CT-901 /# cat /sys/fs/cgroup/memory/cgroup.subgroups_limit > > 512 > > CT-901 /# echo 3333 > /sys/fs/cgroup/memory/cgroup.subgroups_limit > > -bash: echo: write error: Operation not permitted > > CT-901 /# echo 333 > /sys/fs/cgroup/memory/cgroup.subgroups_limit > > -bash: echo: write error: Operation not permitted > > > > I doubt this way can be accepted in upstream, however for OpenVz > > something like this it is mandatory because it much better > > than nothing. > > Is this customization of yours something like cgroup.max.descendants on > the unified (v2) hierarchy? (Just curious.) > > (It can be made inaccessible from within the subtree either with cgroup > ns or good old FS permissions.) So we already do have a limit to prevent somebody from running away with the number of cgroups. Nice! I was not aware of that and I guess this looks like the right thing to do. So do we need more control and accounting that this? -- Michal Hocko SUSE Labs