From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754109Ab1GRQix (ORCPT ); Mon, 18 Jul 2011 12:38:53 -0400 Received: from mga02.intel.com ([134.134.136.20]:21758 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753471Ab1GRQit (ORCPT ); Mon, 18 Jul 2011 12:38:49 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.67,223,1309762800"; d="scan'208";a="27206345" Subject: Re: vfsmount lock issues on very large ppc64 box From: Tim Chen To: Matthew Wilcox Cc: Anton Blanchard , npiggin@kernel.dk, viro@zeniv.linux.org.uk, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Andi Kleen , Alexander Viro In-Reply-To: <20110717010427.GC5359@parisc-linux.org> References: <20110717105027.53cc3ca4@kryten> <20110717010427.GC5359@parisc-linux.org> Content-Type: text/plain; charset="UTF-8" Date: Mon, 18 Jul 2011 09:41:16 -0700 Message-ID: <1311007276.2707.37.camel@schen9-DESK> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 (2.28.3-1.fc12) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2011-07-16 at 19:04 -0600, Matthew Wilcox wrote: > On Sun, Jul 17, 2011 at 10:50:27AM +1000, Anton Blanchard wrote: > > Looking closer, all of these calls are in pipefs and sockfs. > > Since we never mount either filesystem they never get a long term > > reference and we always end up in the very slow write brlock path > > that takes a lock for each online CPU. > > > > Here is a quick hack that takes a long term reference on pipefs > > and sockfs which fixes the problem. Any thoughts on how we should > > fix it properly? > > I know Tim and Andi have been looking into this ... I forget what their > fix was though. > I've sent out a trial patch a while ago on this problem, but didn't get a response back. Nick or Al, can you take another look at this patch now that other folks are also running into this issue? http://marc.info/?l=linux-fsdevel&m=130273200502778&w=2 Thanks. Tim