From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ee0-f52.google.com (mail-ee0-f52.google.com [74.125.83.52]) by kanga.kvack.org (Postfix) with ESMTP id 451C66B0031 for ; Sat, 19 Apr 2014 05:15:10 -0400 (EDT) Received: by mail-ee0-f52.google.com with SMTP id e49so2184950eek.25 for ; Sat, 19 Apr 2014 02:15:09 -0700 (PDT) Received: from mail-ee0-x229.google.com (mail-ee0-x229.google.com [2a00:1450:4013:c00::229]) by mx.google.com with ESMTPS id 43si43973193eei.295.2014.04.19.02.15.08 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Sat, 19 Apr 2014 02:15:08 -0700 (PDT) Received: by mail-ee0-f41.google.com with SMTP id t10so2261013eei.28 for ; Sat, 19 Apr 2014 02:15:08 -0700 (PDT) Message-ID: <53523E93.4060702@gmail.com> Date: Sat, 19 Apr 2014 11:14:59 +0200 From: "Michael Kerrisk (man-pages)" MIME-Version: 1.0 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: owner-linux-mm@kvack.org List-ID: 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" 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, 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 From mboxrd@z Thu Jan 1 00:00:00 1970 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/