From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755818AbZBIQGU (ORCPT ); Mon, 9 Feb 2009 11:06:20 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754648AbZBIQGM (ORCPT ); Mon, 9 Feb 2009 11:06:12 -0500 Received: from rcsinet13.oracle.com ([148.87.113.125]:38517 "EHLO rgminet13.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754620AbZBIQGL (ORCPT ); Mon, 9 Feb 2009 11:06:11 -0500 Subject: Re: Build failure with latest -git: btrfs on ppc64 From: Chris Mason To: Kyle McMartin Cc: Chuck Ebbert , linux-kernel@vger.kernel.org, Ingo Molnar In-Reply-To: <20090209155702.GB13529@bombadil.infradead.org> References: <20090207155039.3b6a7429@dhcp-100-2-144.bos.redhat.com> <20090207232458.GB23407@bombadil.infradead.org> <1234191446.1262.3.camel@think.oraclecorp.com> <20090209155702.GB13529@bombadil.infradead.org> Content-Type: text/plain Date: Mon, 09 Feb 2009 11:05:39 -0500 Message-Id: <1234195539.5447.2.camel@think.oraclecorp.com> Mime-Version: 1.0 X-Mailer: Evolution 2.24.1 Content-Transfer-Encoding: 7bit X-Source-IP: acsmt707.oracle.com [141.146.40.85] X-Auth-Type: Internal IP X-CT-RefId: str=0001.0A09020A.49905457.0036:SCFSTAT928724,ss=1,fgs=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2009-02-09 at 10:57 -0500, Kyle McMartin wrote: > On Mon, Feb 09, 2009 at 09:57:26AM -0500, Chris Mason wrote: > > > > Ok, I thought this would be defined to something simple for the > > non-ticket users, should I just not be using this call? > > > > I think the use is fine, since it's really a judgement call based on > whether there's waiters for the ticket. I need to take a closer look > at where this is used to say... > The Btrfs use goes something like this: I'm about to wait for the disk. If there are other procs waiting for the locks I'm holding, I'll drop my locks and do a somewhat expensive btree search over again later so the waiters can make progress. If nobody is waiting, I'll do my read with my locks held so that I don't have to search again. > It's inevitable for you to hit things like this though, as far as I know > you're the first user of this lock interface. :) ;) -chris