From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 20 Jun 2006 15:35:55 -0700 From: Andrew Morton 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> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Nick Piggin Cc: benh@kernel.crashing.org, Paul.McKenney@us.ibm.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: 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. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org