From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oa0-f49.google.com (mail-oa0-f49.google.com [209.85.219.49]) by kanga.kvack.org (Postfix) with ESMTP id 357286B005A for ; Tue, 1 Apr 2014 17:01:07 -0400 (EDT) Received: by mail-oa0-f49.google.com with SMTP id o6so1410021oag.22 for ; Tue, 01 Apr 2014 14:01:06 -0700 (PDT) Received: from g4t3426.houston.hp.com (g4t3426.houston.hp.com. [15.201.208.54]) by mx.google.com with ESMTPS id yv5si15996656oeb.36.2014.04.01.14.01.06 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Tue, 01 Apr 2014 14:01:06 -0700 (PDT) Message-ID: <1396386062.25314.24.camel@buesod1.americas.hpqcorp.net> Subject: Re: [PATCH] ipc,shm: increase default size for shmmax From: Davidlohr Bueso 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" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: KOSAKI Motohiro Cc: Andrew Morton , Manfred Spraul , aswin@hp.com, LKML , "linux-mm@kvack.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, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org