From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: with ECARTIS (v1.0.0; list xfs); Thu, 26 Jun 2008 04:41:57 -0700 (PDT) Received: from cuda.sgi.com (cuda1.sgi.com [192.48.168.28]) by oss.sgi.com (8.12.11.20060308/8.12.11/SuSE Linux 0.7) with ESMTP id m5QBfrV6009976 for ; Thu, 26 Jun 2008 04:41:53 -0700 Received: from mail.parisc-linux.org (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id D6AEF11D5A71 for ; Thu, 26 Jun 2008 04:42:53 -0700 (PDT) Received: from mail.parisc-linux.org (palinux.external.hp.com [192.25.206.14]) by cuda.sgi.com with ESMTP id 78BR6XQFRJSxIvmH for ; Thu, 26 Jun 2008 04:42:53 -0700 (PDT) Date: Thu, 26 Jun 2008 05:42:42 -0600 From: Matthew Wilcox Subject: Re: [PATCH 1/6] Extend completions to provide XFS object flush requirements Message-ID: <20080626114242.GX4392@parisc-linux.org> References: <1214455277-6387-1-git-send-email-david@fromorbit.com> <1214455277-6387-2-git-send-email-david@fromorbit.com> <20080626112612.GW4392@parisc-linux.org> <20080626113209.GK11558@disturbed> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080626113209.GK11558@disturbed> Sender: xfs-bounce@oss.sgi.com Errors-to: xfs-bounce@oss.sgi.com List-Id: xfs To: xfs@oss.sgi.com, linux-kernel@vger.kernel.org On Thu, Jun 26, 2008 at 09:32:09PM +1000, Dave Chinner wrote: > On Thu, Jun 26, 2008 at 05:26:12AM -0600, Matthew Wilcox wrote: > > On Thu, Jun 26, 2008 at 02:41:12PM +1000, Dave Chinner wrote: > > > XFS object flushing doesn't quite match existing completion semantics. It > > > mixed exclusive access with completion. That is, we need to mark an object as > > > being flushed before flushing it to disk, and then block any other attempt to > > > flush it until the completion occurs. > > > > This sounds like mutex semantics. Why are the existing mutexes not > > appropriate for your needs? > > Different threads doing wait and complete. Then let's leave it as a semaphore. You can get rid of the sema_t if you like, but I don't think that turning completions into semaphores is a good idea (because it's confusing). -- Intel are signing my paycheques ... these opinions are still mine "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step."