From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754621AbZHKSZ1 (ORCPT ); Tue, 11 Aug 2009 14:25:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753825AbZHKSZ1 (ORCPT ); Tue, 11 Aug 2009 14:25:27 -0400 Received: from acsinet11.oracle.com ([141.146.126.233]:30080 "EHLO acsinet11.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753633AbZHKSZ0 (ORCPT ); Tue, 11 Aug 2009 14:25:26 -0400 Message-ID: <4A81B728.7040200@oracle.com> Date: Tue, 11 Aug 2009 11:23:36 -0700 From: Zach Brown User-Agent: Thunderbird 2.0.0.22 (Macintosh/20090605) MIME-Version: 1.0 To: Manfred Spraul CC: npiggin@suse.de, Andrew Morton , Nadia Derbey , Pierre Peiffer , linux-kernel@vger.kernel.org Subject: Re: [patch 4/4] ipc: sem optimise simple operations References: <20090811110902.255877673@suse.de> <20090811111607.310739140@suse.de> <4A81B646.5060301@colorfullife.com> In-Reply-To: <4A81B646.5060301@colorfullife.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Source-IP: abhmt001.oracle.com [141.146.116.10] X-Auth-Type: Internal IP X-CT-RefId: str=0001.0A010208.4A81B72B.00FE:SCFSTAT5015188,ss=1,fgs=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Manfred Spraul wrote: > On 08/11/2009 01:09 PM, npiggin@suse.de wrote: >> Index: linux-2.6/include/linux/sem.h >> =================================================================== >> --- linux-2.6.orig/include/linux/sem.h >> +++ linux-2.6/include/linux/sem.h >> @@ -86,6 +86,8 @@ struct task_struct; >> struct sem { >> int semval; /* current value */ >> int sempid; /* pid of last operation */ >> + struct list_head negv_pending; >> + struct list_head zero_pending; >> }; >> > struct sem is increased from 8 to 24 bytes. And larger still with 64bit pointers. If it's a problem, this can be scaled back. You can have pointers to lists and you can have fewer lists. Hopefully it won't be a problem, though. We can close our eyes and pretend that the size of the semaphore sets scale with the size of the system and that it's such a relatively small consumer of memory that no one will notice :). - z