Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751321AbaDSIpk (ORCPT ); Sat, 19 Apr 2014 04:45:40 -0400 Received: from mail-ee0-f46.google.com ([74.125.83.46]:45426 "EHLO mail-ee0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750996AbaDSIpg (ORCPT ); Sat, 19 Apr 2014 04:45:36 -0400 Message-ID: <535237AA.7080000@colorfullife.com> Date: Sat, 19 Apr 2014 10:45:30 +0200 From: Manfred Spraul User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.4.0 MIME-Version: 1.0 To: mtk.manpages@gmail.com, Davidlohr Bueso CC: 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> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed 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 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. -- Manfred -- 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/