From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753988AbaFCT0I (ORCPT ); Tue, 3 Jun 2014 15:26:08 -0400 Received: from g4t3426.houston.hp.com ([15.201.208.54]:15120 "EHLO g4t3426.houston.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751489AbaFCT0G (ORCPT ); Tue, 3 Jun 2014 15:26:06 -0400 Message-ID: <1401823560.4911.2.camel@buesod1.americas.hpqcorp.net> Subject: Re: [PATCH 0/4] ipc/shm.c: increase the limits for SHMMAX, SHMALL From: Davidlohr Bueso To: mtk.manpages@gmail.com Cc: Manfred Spraul , Davidlohr Bueso , Martin Schwidefsky , LKML , Andrew Morton , KAMEZAWA Hiroyuki , KOSAKI Motohiro , Greg Thelen , aswin@hp.com, "linux-mm@kvack.org" Date: Tue, 03 Jun 2014 12:26:00 -0700 In-Reply-To: References: <1398090397-2397-1-git-send-email-manfred@colorfullife.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.6.4 (3.6.4-3.fc18) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2014-05-02 at 15:16 +0200, Michael Kerrisk (man-pages) wrote: > Hi Manfred, > > On Mon, Apr 21, 2014 at 4:26 PM, Manfred Spraul > wrote: > > Hi all, > > > > the increase of SHMMAX/SHMALL is now a 4 patch series. > > I don't have ideas how to improve it further. > > On the assumption that your patches are heading to mainline, could you > send me a man-pages patch for the changes? It seems we're still behind here and the 3.16 merge window is already opened. Please consider this, and again feel free to add/modify as necessary. I think adding a note as below is enough and was hesitant to add a lot of details... Thanks. 8<-------------------------------------------------- From: Davidlohr Bueso Subject: [PATCH] shmget.2: document new limits for shmmax/shmall These limits have been recently enlarged and modifying them is no longer really necessary. Update the manpage. Signed-off-by: Davidlohr Bueso --- man2/shmget.2 | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/man2/shmget.2 b/man2/shmget.2 index f781048..77764ea 100644 --- a/man2/shmget.2 +++ b/man2/shmget.2 @@ -299,6 +299,11 @@ with 8kB page size, it yields 2^20 (1048576). On Linux, this limit can be read and modified via .IR /proc/sys/kernel/shmall . +As of Linux 3.16, the default value for this limit is increased to +.B ULONG_MAX - 2^24 +pages, which is as large as it can be without helping userspace overflow +the values. Modifying this limit is therefore discouraged. This is suitable +for both 32 and 64-bit systems. .TP .B SHMMAX Maximum size in bytes for a shared memory segment. @@ -306,6 +311,12 @@ Since Linux 2.2, the default value of this limit is 0x2000000 (32MB). On Linux, this limit can be read and modified via .IR /proc/sys/kernel/shmmax . +As of Linux 3.16, the default value for this limit is increased from 32Mb +to +.B ULONG_MAX - 2^24 +bytes, which is as large as it can be without helping userspace overflow +the values. Modifying this limit is therefore discouraged. This is suitable +for both 32 and 64-bit systems. .TP .B SHMMIN Minimum size in bytes for a shared memory segment: implementation -- 1.8.1.4