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Tue, 28 Jun 2022 02:22:36 -0700 (PDT) Date: Tue, 28 Jun 2022 18:22:33 +0900 From: Tejun Heo To: Michal =?iso-8859-1?Q?Koutn=FD?= Cc: Vasily Averin , Roman Gushchin , Shakeel Butt , Michal Hocko , 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> <17916824-ba97-68ba-8166-9402d5f4440c@openvz.org> <20220628091648.GA12249@blackbody.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20220628091648.GA12249@blackbody.suse.cz> ARC-Authentication-Results: i=1; imf19.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=To1tuJ6e; dmarc=fail reason="SPF not aligned (relaxed), DKIM not aligned (relaxed)" header.from=kernel.org (policy=none); 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dkim=pass header.d=gmail.com header.s=20210112 header.b=To1tuJ6e; dmarc=fail reason="SPF not aligned (relaxed), DKIM not aligned (relaxed)" header.from=kernel.org (policy=none); spf=pass (imf19.hostedemail.com: domain of htejun@gmail.com designates 209.85.216.41 as permitted sender) smtp.mailfrom=htejun@gmail.com X-Rspam-User: X-Rspamd-Server: rspam04 X-HE-Tag: 1656408157-185644 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 Tue, Jun 28, 2022 at 11:16:48AM +0200, Michal Koutný wrote: > The mkdir(2) manpage doesn't list EAGAIN at all. ENOSPC makes better > sense here. (And I suspect the dependency on this particular value won't > be very wide spread.) Given how we use these system calls as triggers for random kernel operations, I don't think adhering to posix standard is necessary or possible. Using an error code which isn't listed in the man page isn't particularly high in the list of discrepancies. Again, I'm not against changing it but I'd like to see better rationales. On one side, we have "it's been this way for a long time and there's nothing particularly broken about it". I'm not sure the arguments we have for the other side is strong enough yet. Thanks. -- tejun