From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751426AbWFTWdY (ORCPT ); Tue, 20 Jun 2006 18:33:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751401AbWFTWcv (ORCPT ); Tue, 20 Jun 2006 18:32:51 -0400 Received: from smtp.osdl.org ([65.172.181.4]:56011 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S1751362AbWFTWcr (ORCPT ); Tue, 20 Jun 2006 18:32:47 -0400 Date: Tue, 20 Jun 2006 15:35:55 -0700 From: Andrew Morton To: Nick Piggin Cc: benh@kernel.crashing.org, Paul.McKenney@us.ibm.com, linux-kernel@vger.kernel.org, npiggin@suse.de, linux-mm@kvack.org Subject: Re: [patch 0/3] 2.6.17 radix-tree: updates and lockless Message-Id: <20060620153555.0bd61e7b.akpm@osdl.org> In-Reply-To: <20060408134635.22479.79269.sendpatchset@linux.site> References: <20060408134635.22479.79269.sendpatchset@linux.site> X-Mailer: Sylpheed version 1.0.0 (GTK+ 1.2.10; i386-vine-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Nick Piggin wrote: > > I've finally ported the RCU radix tree over my radix tree direct-data patch > (the latter patch has been in -mm for a while now). Yes, radix-tree-direct-data.patch and radix-tree-small.patch are for-2.6.18. > I've also done the last step required for submission, which was to make a > small userspace RCU test harness, and wire up the rtth so that it can handle > multiple threads to test the lockless capability. The RCU test harness uses > an implementation somewhat like Paul's paper's quiescent state bitmask > approach; with infrequent quiescent state updates, performance isn't bad. > > This quickly flushed out several obscure bugs just when running on my dual > G5. After fixing those, I racked up about 100 CPU hours of testing on > SUSE's 64-way Altix without problem. Also passes the normal battery of > single threaded rtth tests. > > I'd like to hear views regarding merging these patches for 2.6.18. Initially > the lockless code would not come into effect (good - one thing at a time) > until tree_lock can start getting lifted in -mm and 2.6.19. For 2.6.18 we obviously need to fix the tree_lock box-killer as #1 priority. And whatever we do there needs to be backportable to 2.6.17. Depending upon Dave's testing results that'll be either covert-to-spinlock or disable-rwlock-debugging-if-CONFIG_DEBUG_SPINLOCK. Or something else. We'll see. So given those complexities, and the lack of a _user_ of radix-tree-rcu-lockless-readside.patch, it doesn't look like 2.6.18 stuff at this time.