From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751613AbXCXVlv (ORCPT ); Sat, 24 Mar 2007 17:41:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751564AbXCXVlu (ORCPT ); Sat, 24 Mar 2007 17:41:50 -0400 Received: from smtp.osdl.org ([65.172.181.24]:51537 "EHLO smtp.osdl.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751527AbXCXVlu (ORCPT ); Sat, 24 Mar 2007 17:41:50 -0400 Date: Sat, 24 Mar 2007 13:41:28 -0800 From: Andrew Morton To: Nick Piggin Cc: mingo@elte.hu, linux-kernel@vger.kernel.org, kiran@scalex86.org Subject: Re: [rfc][patch] queued spinlocks (i386) Message-Id: <20070324134128.7882f905.akpm@linux-foundation.org> In-Reply-To: <20070323103243.GE11577@wotan.suse.de> References: <20070323085910.GA11577@wotan.suse.de> <20070323100418.GA30740@elte.hu> <20070323103243.GE11577@wotan.suse.de> X-Mailer: Sylpheed version 2.2.4 (GTK+ 2.8.19; 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 > On Fri, 23 Mar 2007 11:32:44 +0100 Nick Piggin wrote: > > I'm not as concerned about the contended performance of spinlocks > The contended case matters. Back in 2.5.something I screwed up the debug version of one of the locks (rwlock, iirc) - it was simply missing a cpu_relax(), and some people's benchmarks halved. > This was just something I had in mind when the hardware lock > starvation issue came up It looks like a good way to address the lru_lock starvation/capture problem. But I think I'd be more comfortable if we were to introduce it as a new lock type, rather than as a reimplementation of the existing spin_lock(). Initially, at least.