From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id o8T6RefX026732 for ; Wed, 29 Sep 2010 01:27:40 -0500 Received: from mail.internode.on.net (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 3B380B17B9 for ; Tue, 28 Sep 2010 23:28:37 -0700 (PDT) Received: from mail.internode.on.net (bld-mail17.adl2.internode.on.net [150.101.137.102]) by cuda.sgi.com with ESMTP id kEF4CMWZFYUQX1Ks for ; Tue, 28 Sep 2010 23:28:37 -0700 (PDT) Date: Wed, 29 Sep 2010 16:28:34 +1000 From: Dave Chinner Subject: Re: [PATCH] xfs: reduce lock traffic on incore sb lock Message-ID: <20100929062834.GM5665@dastard> References: <1285721500-5671-1-git-send-email-david@fromorbit.com> <20100929040425.GA29691@infradead.org> <20100929055748.GK5665@dastard> <20100929061351.GA20921@infradead.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20100929061351.GA20921@infradead.org> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: Christoph Hellwig Cc: xfs@oss.sgi.com On Wed, Sep 29, 2010 at 02:13:51AM -0400, Christoph Hellwig wrote: > On Wed, Sep 29, 2010 at 03:57:48PM +1000, Dave Chinner wrote: > > FWIW, I've got a prototype that converts the per-cpu counters to the > > generic per-cpu counter infrastructure. It chops out almost all the > > xfs_icsb_* stuff (including xfs_icsb_modify_counters()) and has a > > diffstat of: > > Sounds good - I always throught of the balanced per-cpu counters as > infrastructure that really shouldn't sit inside XFS. The only reason I implemented them like that in the first place was that there was no generic per-cpu counter infrastructure in 2.6.15... ;) > > It needs a significant cleanup of xfs_mod_incore_sb() before/after > > the conversion which I haven't done yet because I haven't quite got > > my new percpu_counter_test_and_add_delta() function working > > correctly yet. I spotted this locking problem when testing the > > patch... > > > > That said, there's no reason why my percpu counter code needs to run > > through xfs_mod_incore_sb() at all. If we have a separate path for > > per-cpu counters then I can rework my code on top of that.... > > We'll always need a low-level function to to the actual superblock > updates and a high-level one modifying the per-cpu counters. I don't > think the exact naming matters too much. Agreed. I think it's probably best to wait for your cleanup patches before reworking the counter implementation completely, though. Cheers, Dave. -- Dave Chinner david@fromorbit.com _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs