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From: Roman Gushchin To: Vasily Averin Cc: Shakeel Butt , Michal =?iso-8859-1?Q?Koutn=FD?= , Michal Hocko , Tejun Heo , Zefan Li , Johannes Weiner , kernel@openvz.org, linux-kernel@vger.kernel.org, Andrew Morton , linux-mm@kvack.org, Vlastimil Babka , Muchun Song , cgroups@vger.kernel.org Subject: Re: [PATCH cgroup] cgroup: set the correct return code if hierarchy limits are reached Message-ID: References: <186d5b5b-a082-3814-9963-bf57dfe08511@openvz.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1656377085; a=rsa-sha256; cv=none; b=M2QL6On6chBMS8AaUHH2KgPA52lgrCuTvIvHzwKF/5id4xLiJjk1aMG+wSOYJ0jTQh2Bd7 Q7/AaZA/MRNCoNLnjWp1zO1kztWPSOeflL5Gj5f7jl92ZnRWLVF7xqSrTDWqtjYyTEVzsn QR3eNUyPQQ0eBmWbcHntbn8FDikxBo8= ARC-Authentication-Results: i=1; imf27.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=ekLEYclU; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf27.hostedemail.com: domain of roman.gushchin@linux.dev designates 91.121.223.63 as permitted sender) smtp.mailfrom=roman.gushchin@linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1656377085; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=BJKVsQcWiOvVBIN6ILcbyfHw9khWxf41DSkNpqOzqMc=; b=Imz8kuid+5El2uQkYETFda9x4gocdND0+rHnFkLDA5s1rhzHb58/6Idqd0ssaVvTUY0gch IZbMdYEwVgOmzCeDy1INAX8N9sNeOL/0sNEyP5lODFRXqE7Fy53VsQQiec3OW9WiZSQfyh EhvUQzPwyznBa9pPQffqLmO8bi4rxck= X-Rspam-User: X-Stat-Signature: dp4fk6owutceqd9t3nbnc74nryz8b686 X-Rspamd-Queue-Id: 0D8B34000D Authentication-Results: imf27.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=ekLEYclU; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf27.hostedemail.com: domain of roman.gushchin@linux.dev designates 91.121.223.63 as permitted sender) smtp.mailfrom=roman.gushchin@linux.dev X-Rspamd-Server: rspam03 X-HE-Tag: 1656377084-354595 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 Mon, Jun 27, 2022 at 05:12:55AM +0300, Vasily Averin wrote: > When cgroup_mkdir reaches the limits of the cgroup hierarchy, it should > not return -EAGAIN, but instead react similarly to reaching the global > limit. > > Signed-off-by: Vasily Averin > --- > kernel/cgroup/cgroup.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c > index 1be0f81fe8e1..243239553ea3 100644 > --- a/kernel/cgroup/cgroup.c > +++ b/kernel/cgroup/cgroup.c > @@ -5495,7 +5495,7 @@ int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, umode_t mode) > return -ENODEV; > > if (!cgroup_check_hierarchy_limits(parent)) { > - ret = -EAGAIN; > + ret = -ENOSPC; I'd not argue whether ENOSPC is better or worse here, but I don't think we need to change it now. It's been in this state for a long time and is a part of ABI. EAGAIN is pretty unique as a mkdir() result, so systemd can handle it well. Thanks!