Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751341AbaDQUTu (ORCPT ); Thu, 17 Apr 2014 16:19:50 -0400 Received: from mail-pd0-f177.google.com ([209.85.192.177]:58996 "EHLO mail-pd0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750852AbaDQUTo (ORCPT ); Thu, 17 Apr 2014 16:19:44 -0400 MIME-Version: 1.0 Reply-To: mtk.manpages@gmail.com In-Reply-To: <5350042F.4040904@colorfullife.com> References: <1396235199.2507.2.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> <1396389751.25314.26.camel@buesod1.americas.hpqcorp.net> <20140401150843.13da3743554ad541629c936d@linux-foundation.org> <534AD1EE.3050705@colorfullife.com> <20140416154631.6d0173498c60619d454ae651@linux-foundation.org> <5350042F.4040904@colorfullife.com> From: "Michael Kerrisk (man-pages)" Date: Thu, 17 Apr 2014 22:19:23 +0200 Message-ID: Subject: Re: [PATCH] ipc,shm: increase default size for shmmax To: Manfred Spraul Cc: Andrew Morton , Davidlohr Bueso , KOSAKI Motohiro , aswin@hp.com, LKML , "linux-mm@kvack.org" Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 17, 2014 at 6:41 PM, Manfred Spraul wrote: > On 04/17/2014 12:41 PM, Michael Kerrisk wrote: >> >> On Thu, Apr 17, 2014 at 12:46 AM, Andrew Morton >> wrote: >>> >>> On Sun, 13 Apr 2014 20:05:34 +0200 Manfred Spraul >>> wrote: >>> >>>> Hi Andrew, >>>> >>>> On 04/02/2014 12:08 AM, Andrew Morton wrote: >>>>> >>>>> Well, I'm assuming 64GB==infinity. It *was* infinity in the RHEL5 >>>>> timeframe, but infinity has since become larger so pickanumber. >>>> >>>> I think infinity is the right solution: >>>> The only common case where infinity is wrong would be Android - and >>>> Android disables sysv shm entirely. >>>> >>>> There are two patches: >>>> http://marc.info/?l=linux-kernel&m=139730332306185&q=raw >>>> http://marc.info/?l=linux-kernel&m=139727299800644&q=raw >>>> >>>> Could you apply one of them? >>>> I wrote the first one, thus I'm biased which one is better. >>> >>> I like your patch because applying it might encourage you to send more >>> kernel patches - I miss the old days ;) >>> >>> But I do worry about disrupting existing systems so I like Davidlohr's >>> idea of making the change a no-op for people who are currently >>> explicitly setting shmmax and shmall. >> >> Agreed. It's hard to imagine situations where people might care >> nowadays, but there's no limits to people's insane inventiveness. Some >> people really might want to set an upper limit. > > I don't understand that: neither patch has any impact after an explicit > sysctl that overwrites shmmax. You don't understand it, because I was being dense :-}. I misunderstood your patch. I think I was thrown by this line in the commit message: The patch disables both limits by setting the limits to ULONG_MAX. Of course, you patch doesn't *disable* the limits, it simply sets the defaults to the maximum. >>> In an ideal world, system administrators would review this change, >> >> And in the ideal world, patches such as this would CC >> linux-api@vger.kernel.org, as described in >> Documentation/SubmitChecklist, so that users who care about getting >> advance warning on API changes could be alerted and might even review >> and comment... > > Good point. > Davidlohr: Your patch has an impact on shmctl(,IPC_INFO,). > Could you add that for v3? Well, actually, BOTH patches change the API, because they both affect SHMALL/SHMMAX. Cheers, Michael > I'll try to make a v2 (with your update to the uapi header file) tomorrow. > > -- > Manfred -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/ -- 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/