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[37.188.135.150]) by smtp.gmail.com with ESMTPSA id 195sm3660380wmb.8.2020.03.26.06.39.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 26 Mar 2020 06:39:17 -0700 (PDT) Date: Thu, 26 Mar 2020 14:39:15 +0100 From: Michal Hocko To: Christian Brauner Cc: "Eric W. Biederman" , Vlastimil Babka , Luis Chamberlain , Kees Cook , Iurii Zaikin , linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, linux-mm@kvack.org, Ivan Teterevkov , David Rientjes , Matthew Wilcox , "Guilherme G . Piccoli" Subject: Re: [RFC v2 1/2] kernel/sysctl: support setting sysctl parameters from kernel command line Message-ID: <20200326133915.GQ27965@dhcp22.suse.cz> References: <20200325120345.12946-1-vbabka@suse.cz> <874kuc5b5z.fsf@x220.int.ebiederm.org> <20200326065829.GC27965@dhcp22.suse.cz> <20200326133041.a3zit3gzdqmphane@wittgenstein> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200326133041.a3zit3gzdqmphane@wittgenstein> 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 Thu 26-03-20 14:30:41, Christian Brauner wrote: > On Thu, Mar 26, 2020 at 07:58:29AM +0100, Michal Hocko wrote: > > On Wed 25-03-20 17:20:40, Eric W. Biederman wrote: > > > Vlastimil Babka writes: > > [...] > > > > + if (strncmp(param, "sysctl.", sizeof("sysctl.") - 1)) > > > > + return 0; > > > > > > Is there any way we can use a slash separated path. I know > > > in practice there are not any sysctl names that don't have > > > a '.' in them but why should we artifically limit ourselves? > > > > Because this is the normal userspace interface? Why should it be any > > different from calling sysctl? > > [...] > > Imho, we should use ".". Kernel developers aren't the ones setting > these options, admins are and if I think back to the times doing that as > a job at uni I'd be very confused if I learned that I get to set sysctl > options through the kernel command but need to use yet another format > than what I usually do to set those from the shell. Consistency is most > of the times to be preferred imho. Absolutely agreed! Even if sysctl can consume / instead of ., which was a news to me btw, the majority of the usage is with `.' -- Michal Hocko SUSE Labs