From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keir Fraser Subject: Re: [PATCH 1/2, v2] x86: replace nr_irqs sized per-domain arrays with radix trees Date: Wed, 04 May 2011 20:55:02 +0100 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Dan Magenheimer , Jan Beulich Cc: xen-devel@lists.xensource.com, Allen M Kay List-Id: xen-devel@lists.xenproject.org On 04/05/2011 17:13, "Dan Magenheimer" wrote: > After some offlist discussion, for kztmem (later renamed "the new > zcache"), I ended up extracting the essence of the radix-tree data > structure and adapting it inline specifically for my in-kernel tmem > needs. While I'm not a fan of duplicating code, this was an > expedient way to avoid a political quagmire. > > Ideally, the Xen radix-tree.c would support both needs through some > kind of layering, but if your preference is to go to the upstream > Linux radix-tree.c, I can probably leverage my inlined-radix-tree > code into Xen tmem.c. I don't expect it will be trivial though. I'm sure I can pull in upstream radix-tree.c and get Xen's tmem ported onto it. As for performance, I may leave the tagging stuff out as we won't need it. Then it's just quibbling over RCU overheads, which I would bet are manageable. We can modify radix-tree.c further if there is good reason for it. -- Keir