From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753227AbaCaDGn (ORCPT ); Sun, 30 Mar 2014 23:06:43 -0400 Received: from g6t1524.atlanta.hp.com ([15.193.200.67]:49414 "EHLO g6t1524.atlanta.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752634AbaCaDGm (ORCPT ); Sun, 30 Mar 2014 23:06:42 -0400 Message-ID: <1396235199.2507.2.camel@buesod1.americas.hpqcorp.net> Subject: [PATCH] ipc,shm: increase default size for shmmax From: Davidlohr Bueso To: Andrew Morton Cc: Manfred Spraul , Davidlohr Bueso , aswin@hp.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org Date: Sun, 30 Mar 2014 20:06:39 -0700 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 From: Davidlohr Bueso The default size is, and always has been, 32Mb. Today, in the XXI century, it seems that this value is rather small, making users have to increase it via sysctl, which can cause unnecessary work and userspace application workarounds[1]. I have arbitrarily chosen a 4x increase, leaving it at 128Mb, and naturally, the same goes for shmall. While it may make more sense to set the value based on the system memory, this limit must be the same across all systems, and left to users to change if needed. [1]: http://rhaas.blogspot.com/2012/06/absurd-shared-memory-limits.html Signed-off-by: Davidlohr Bueso --- include/uapi/linux/shm.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/uapi/linux/shm.h b/include/uapi/linux/shm.h index 78b6941..754b605 100644 --- a/include/uapi/linux/shm.h +++ b/include/uapi/linux/shm.h @@ -12,7 +12,7 @@ * be increased by sysctl */ -#define SHMMAX 0x2000000 /* max shared seg size (bytes) */ +#define SHMMAX 0x8000000 /* max shared seg size (bytes) */ #define SHMMIN 1 /* min shared seg size (bytes) */ #define SHMMNI 4096 /* max num of segs system wide */ #ifndef __KERNEL__ -- 1.8.1.4