Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751351AbaDSJPO (ORCPT ); Sat, 19 Apr 2014 05:15:14 -0400 Received: from mail-ee0-f49.google.com ([74.125.83.49]:38152 "EHLO mail-ee0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750905AbaDSJPJ (ORCPT ); Sat, 19 Apr 2014 05:15:09 -0400 Message-ID: <53523E93.4060702@gmail.com> Date: Sat, 19 Apr 2014 11:14:59 +0200 From: "Michael Kerrisk (man-pages)" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.4.0 MIME-Version: 1.0 To: Manfred Spraul , Davidlohr Bueso CC: mtk.manpages@gmail.com, Andrew Morton , Davidlohr Bueso , LKML , KAMEZAWA Hiroyuki , KOSAKI Motohiro , Greg Thelen , aswin@hp.com, "linux-mm@kvack.org" Subject: Re: [PATCH] ipc/shm: Increase the defaults for SHMALL, SHMMAX to infinity References: <1397812720-5629-1-git-send-email-manfred@colorfullife.com> <1397890512.19331.21.camel@buesod1.americas.hpqcorp.net> <535237AA.7080000@colorfullife.com> In-Reply-To: <535237AA.7080000@colorfullife.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/19/2014 10:45 AM, Manfred Spraul wrote: > On 04/19/2014 09:10 AM, Michael Kerrisk (man-pages) wrote: >> On Sat, Apr 19, 2014 at 8:55 AM, Davidlohr Bueso wrote: >>> On Fri, 2014-04-18 at 11:18 +0200, Manfred Spraul wrote: >>>> Risks: >>>> - The patch breaks installations that use "take current value and increase >>>> it a bit". [seems to exist, http://marc.info/?l=linux-mm&m=139638334330127] >>> This really scares me. The probability of occurrence is now much higher, >>> and not just theoretical. It would legitimately break userspace. >> I'm missing something. Manfred's patch doesn't actually change the >> behavior on this point does it? If the problem is more than >> theoretical, then it _already_ affects users, right? (And they would >> therefore already be working around the problem.) > The current default is 32 MB. if some increases it by 1 MB, then the > result is 33 MB. > The new default would be ULONG_MAX. If someone increases it by 1 MB, > then the result is 1 MB - 1 byte. Ahh. Got it now--sorry for being slow. -- 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/