Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261694AbVEZSqq (ORCPT ); Thu, 26 May 2005 14:46:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261698AbVEZSqq (ORCPT ); Thu, 26 May 2005 14:46:46 -0400 Received: from omx3-ext.sgi.com ([192.48.171.20]:32206 "EHLO omx3.sgi.com") by vger.kernel.org with ESMTP id S261694AbVEZSqd (ORCPT ); Thu, 26 May 2005 14:46:33 -0400 Date: Thu, 26 May 2005 11:46:09 -0700 From: Paul Jackson To: Linus Torvalds Cc: holt@sgi.com, Simon.Derr@bull.net, akpm@osdl.org, dino@in.ibm.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2.6.12-rc4] cpuset exit NULL dereference fix Message-Id: <20050526114609.2c01a485.pj@sgi.com> In-Reply-To: References: <20050526082508.927.67614.sendpatchset@tomahawk.engr.sgi.com> <20050526120859.GD29852@lnx-holt.americas.sgi.com> Organization: SGI X-Mailer: Sylpheed version 1.0.0 (GTK+ 1.2.10; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 890 Lines: 23 Linus wrote: > For this, there is a nice > > atomic_dec_and_lock() > > function that is the same as "atomic_dec_and_test()", except it grabs the > lock if the count decrements to zero. If we take Robin's idea to add a spinlock per cpuset, then yes this atomic_dec_and_lock() might be useful. Thanks for mentioning it. I am not convinced we need to go that way. See my upcoming replies to Simon and Robin, for alternative approaches that are simpler. -- I won't rest till it's the best ... Programmer, Linux Scalability Paul Jackson 1.650.933.1373, 1.925.600.0401 - 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/