From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161168AbWAHIak (ORCPT ); Sun, 8 Jan 2006 03:30:40 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161166AbWAHIak (ORCPT ); Sun, 8 Jan 2006 03:30:40 -0500 Received: from ozlabs.org ([203.10.76.45]:60650 "EHLO ozlabs.org") by vger.kernel.org with ESMTP id S1161168AbWAHIaj (ORCPT ); Sun, 8 Jan 2006 03:30:39 -0500 Date: Sun, 8 Jan 2006 19:23:01 +1100 From: Anton Blanchard To: Andrew Morton Cc: jes@trained-monkey.org, rmk+lkml@arm.linux.org.uk, ak@suse.de, linux-kernel@vger.kernel.org, hch@infradead.org, torvalds@osdl.org, viro@ftp.linux.org.uk, linuxppc64-dev@ozlabs.org, mingo@elte.hu, nico@cam.org, oleg@tv-sign.ru, alan@lxorguk.ukuu.org.uk, arjan@infradead.org Subject: Re: PowerPC fastpaths for mutex subsystem Message-ID: <20060108082301.GN26499@krispykreme> References: <43BC5E15.207@austin.ibm.com> <20060105143502.GA16816@elte.hu> <43BD4C66.60001@austin.ibm.com> <20060105222106.GA26474@elte.hu> <43BDA672.4090704@austin.ibm.com> <20060106002919.GA29190@pb15.lixom.net> <43BFFF1D.7030007@austin.ibm.com> <20060107143722.25afd85d.akpm@osdl.org> <20060108074356.GM26499@krispykreme> <20060108000021.588c6f5f.akpm@osdl.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060108000021.588c6f5f.akpm@osdl.org> User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > What's "unfair"? Mutexes are FIFO, as are x86 semaphores. The ppc64 semaphores dont force everyone into the slow path under contention. So you could drop and pick up the semaphore even with someone waiting. I thought thats how the new mutex code worked. Anton