From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756919AbZC3MRJ (ORCPT ); Mon, 30 Mar 2009 08:17:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753124AbZC3MQy (ORCPT ); Mon, 30 Mar 2009 08:16:54 -0400 Received: from one.firstfloor.org ([213.235.205.2]:44854 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751253AbZC3MQx (ORCPT ); Mon, 30 Mar 2009 08:16:53 -0400 To: npiggin@suse.de Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [patch 09/14] fs: use RCU / seqlock logic for reverse and multi-step operaitons From: Andi Kleen References: <20090329155539.275927173@nick.local0.net> <20090329155749.609663166@nick.local0.net> Date: Mon, 30 Mar 2009 14:16:49 +0200 In-Reply-To: <20090329155749.609663166@nick.local0.net> (npiggin@suse.de's message of "Mon, 30 Mar 2009 02:55:48 +1100") Message-ID: <874oxbnr2m.fsf@basil.nowhere.org> User-Agent: Gnus/5.1008 (Gnus v5.10.8) Emacs/22.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org npiggin@suse.de writes: > The remaining usages for dcache_lock is to allow atomic, multi-step read-side > operations over the directory tree by excluding modifications to the tree. > Also, to walk in the leaf->root direction in the tree where we don't have > a natural d_lock ordering. This is the hardest bit. General thoughts: is there a way to add a self testing infrastructure to this. e.g. by having more sequence counts per object (only enabled in the debug case, so it doesn't matter when cache line bounces) and lots of checks? I suppose that would lower the work needed of actually fixing this to work significantly. -Andi -- ak@linux.intel.com -- Speaking for myself only.