From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pb0-f52.google.com (mail-pb0-f52.google.com [209.85.160.52]) by kanga.kvack.org (Postfix) with ESMTP id E68346B007B for ; Tue, 1 Apr 2014 18:02:41 -0400 (EDT) Received: by mail-pb0-f52.google.com with SMTP id rr13so10496095pbb.39 for ; Tue, 01 Apr 2014 15:02:41 -0700 (PDT) Received: from g2t2352.austin.hp.com (g2t2352.austin.hp.com. [15.217.128.51]) by mx.google.com with ESMTPS id sr9si1797809pab.325.2014.04.01.15.02.39 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Tue, 01 Apr 2014 15:02:39 -0700 (PDT) Message-ID: <1396389751.25314.26.camel@buesod1.americas.hpqcorp.net> Subject: Re: [PATCH] ipc,shm: increase default size for shmmax From: Davidlohr Bueso Date: Tue, 01 Apr 2014 15:02:31 -0700 In-Reply-To: <20140401144801.603c288674ab8f417b42a043@linux-foundation.org> 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> <1396386062.25314.24.camel@buesod1.americas.hpqcorp.net> <20140401142947.927642a408d84df27d581e36@linux-foundation.org> <20140401144801.603c288674ab8f417b42a043@linux-foundation.org> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: KOSAKI Motohiro , Manfred Spraul , aswin@hp.com, LKML , "linux-mm@kvack.org" On Tue, 2014-04-01 at 14:48 -0700, Andrew Morton wrote: > On Tue, 1 Apr 2014 17:41:54 -0400 KOSAKI Motohiro wrote: > > > >> > 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? > > >> > > >> I don't think people use 0 for disabling. but ULONG_MAX make sense to me too. > > > > > > Distros could have set it to [U]LONG_MAX in initscripts ten years ago > > > - less phone calls, happier customers. And they could do so today. > > > > > > But they haven't. What are the risks of doing this? > > > > I have no idea really. But at least I'm sure current default is much worse. > > > > 1. Solaris changed the default to total-memory/4 since Solaris 10 for DB. > > http://www.postgresql.org/docs/9.1/static/kernel-resources.html > > > > 2. RHEL changed the default to very big size since RHEL5 (now it is > > 64GB). Even tough many box don't have 64GB memory at that time. > > Ah-hah, that's interesting info. > > Let's make the default 64GB? But again, yet another arbitrary value... -- 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