From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Chinner Subject: Re: [PATCH RFC 0/2] skiplists for range indexes Date: Sun, 5 May 2013 17:33:57 +1000 Message-ID: <20130505073357.GC2010@devil.localdomain> References: <20130503020211.3599.72404@localhost.localdomain> <20130503091924.GD10633@quack.suse.cz> <20130503104525.5844.57452@localhost.localdomain> <20130504032536.GD19978@dastard> <20130504111151.5844.74450@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Dave Chinner , Jan Kara , Linux FS Devel , David Woodhouse , "bo.li.liu@oracle.com" To: Chris Mason Return-path: Received: from mx1.redhat.com ([209.132.183.28]:63372 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751417Ab3EEHeO (ORCPT ); Sun, 5 May 2013 03:34:14 -0400 Content-Disposition: inline In-Reply-To: <20130504111151.5844.74450@localhost.localdomain> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Sat, May 04, 2013 at 07:11:51AM -0400, Chris Mason wrote: > Quoting Dave Chinner (2013-05-03 23:25:36) > > > > I've got two cases I care about. The first is the buffer cache > > indexes which have a 1000:1 read:modify ratio and I'd really like the > > lookups to be lockless. The other case is the extent tree, where we > > do lots of inserts when the extent tree is first read, and after > > than it's typically 2 lookups for every insert/remove. Having one > > tree that works for both would be handy... > > Ok, we're in a similar boat then. I'll finish off some of the API and > test the pure RCU side harder. > > For the extent tree, are you doing a lot of merging once things are in > the tree? I'm not planning on doing pure-rcu for items that get merged > quiet yet. Yes, we merge extents where ever possible. Almost all contiguous allocations and unwritten extent conversions merge extents in some manner... > Also, I'm using unsigned longs right now. My guess is we'll both want > u64s, which means I have to do an i_size_read/write trick in a few > spots. Yup, definitely needs to be u64 for XFS... Cheers, Dave. -- Dave Chinner dchinner@redhat.com