From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965095AbWFTJjh (ORCPT ); Tue, 20 Jun 2006 05:39:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965241AbWFTJjh (ORCPT ); Tue, 20 Jun 2006 05:39:37 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:38106 "EHLO mx2.mail.elte.hu") by vger.kernel.org with ESMTP id S965095AbWFTJjg (ORCPT ); Tue, 20 Jun 2006 05:39:36 -0400 Date: Tue, 20 Jun 2006 11:34:33 +0200 From: Ingo Molnar To: Andrew Morton Cc: ccb@acm.org, linux-kernel@vger.kernel.org, Dave Olson Subject: Re: [patch] fix spinlock-debug looping Message-ID: <20060620093433.GB11037@elte.hu> References: <20060619081252.GA13176@elte.hu> <20060619013238.6d19570f.akpm@osdl.org> <20060619083518.GA14265@elte.hu> <20060619021314.a6ce43f5.akpm@osdl.org> <20060619113943.GA18321@elte.hu> <20060619125531.4c72b8cc.akpm@osdl.org> <20060620084001.GC7899@elte.hu> <20060620015259.dab285d5.akpm@osdl.org> <20060620091505.GA9749@elte.hu> <20060620023216.4995edb9.akpm@osdl.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060620023216.4995edb9.akpm@osdl.org> User-Agent: Mutt/1.4.2.1i X-ELTE-SpamScore: -3.1 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-3.1 required=5.9 tests=ALL_TRUSTED,AWL,BAYES_50 autolearn=no SpamAssassin version=3.0.3 -3.3 ALL_TRUSTED Did not pass through any untrusted hosts 0.0 BAYES_50 BODY: Bayesian spam probability is 40 to 60% [score: 0.5000] 0.2 AWL AWL: From: address is in the auto white-list X-ELTE-VirusStatus: clean Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org * Andrew Morton wrote: > > Spinlocks are alot fairer. Or as a simple experiment, > > s/read_lock/write_lock, as the patch below (against rc6-mm2) does. > > This is phase #1, if it works out we can switch tree_lock to a > > spinlock. [write_lock()s are roughly as fair to each other as > > spinlocks - it's a bit more expensive but not significantly] Builds > > & boots fine here. > > tree_lock was initially an rwlock. Then we made it a spinlock. Then > we made it an rwlock. We change the dang thing so often we should > make it a macro ;) ha! In -rt we can change types of locks by changing the type definition and the declaration only ;-) [It makes for some confusing reading though if done without restraint] > Let's just make it a spinlock and be done with it. Hopefully Dave or > ccb@acm.org (?) will be able to test it. I was planning on doing a > patch tomorrowish. ok. Until that happens the patch i sent can be used for testing. Ingo