Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751543AbaDAVBJ (ORCPT ); Tue, 1 Apr 2014 17:01:09 -0400 Received: from g4t3426.houston.hp.com ([15.201.208.54]:14717 "EHLO g4t3426.houston.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751451AbaDAVBH (ORCPT ); Tue, 1 Apr 2014 17:01:07 -0400 Message-ID: <1396386062.25314.24.camel@buesod1.americas.hpqcorp.net> Subject: Re: [PATCH] ipc,shm: increase default size for shmmax From: Davidlohr Bueso To: KOSAKI Motohiro Cc: Andrew Morton , Manfred Spraul , aswin@hp.com, LKML , "linux-mm@kvack.org" Date: Tue, 01 Apr 2014 14:01:02 -0700 In-Reply-To: References: <1396235199.2507.2.camel@buesod1.americas.hpqcorp.net> <20140331143217.c6ff958e1fd9944d78507418@linux-foundation.org> <1396306773.18499.22.camel@buesod1.americas.hpqcorp.net> <20140331161308.6510381345cb9a1b419d5ec0@linux-foundation.org> <1396308332.18499.25.camel@buesod1.americas.hpqcorp.net> <20140331170546.3b3e72f0.akpm@linux-foundation.org> <1396371699.25314.11.camel@buesod1.americas.hpqcorp.net> <1396377083.25314.17.camel@buesod1.americas.hpqcorp.net> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.6.4 (3.6.4-3.fc18) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2014-04-01 at 15:51 -0400, KOSAKI Motohiro wrote: > >> So, I personally like 0 byte per default. > > > > If by this you mean 0 bytes == unlimited, then I agree. It's less harsh > > then removing it entirely. So instead of removing the limit we can just > > set it by default to 0, and in newseg() if shm_ctlmax == 0 then we don't > > return EINVAL if the passed size is great (obviously), otherwise, if the > > user _explicitly_ set it via sysctl then we respect that. Andrew, do you > > agree with this? If so I'll send a patch. > > Yes, my 0 bytes mean unlimited. I totally agree we shouldn't remove the knob > entirely. Hmmm so 0 won't really work because it could be weirdly used to disable shm altogether... we cannot go to some negative value either since we're dealing with unsigned, and cutting the range in half could also hurt users that set the limit above that. So I was thinking of simply setting SHMMAX to ULONG_MAX and be done with it. Users can then set it manually if they want a smaller value. Makes sense? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/