From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Mason Subject: Re: [PATCH RFC 0/2] skiplists for range indexes Date: Sat, 4 May 2013 07:11:51 -0400 Message-ID: <20130504111151.5844.74450@localhost.localdomain> References: <20130503020211.3599.72404@localhost.localdomain> <20130503091924.GD10633@quack.suse.cz> <20130503104525.5844.57452@localhost.localdomain> <20130504032536.GD19978@dastard> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8BIT Cc: Jan Kara , Linux FS Devel , David Woodhouse , "dchinner@redhat.com" , "bo.li.liu@oracle.com" To: Dave Chinner Return-path: Received: from dkim2.fusionio.com ([66.114.96.54]:41369 "EHLO dkim2.fusionio.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757354Ab3EDLLy convert rfc822-to-8bit (ORCPT ); Sat, 4 May 2013 07:11:54 -0400 Received: from mx1.fusionio.com (unknown [10.101.1.160]) by dkim2.fusionio.com (Postfix) with ESMTP id 30DD39A0686 for ; Sat, 4 May 2013 05:11:54 -0600 (MDT) In-Reply-To: <20130504032536.GD19978@dastard> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: 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. 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. -chris