From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrea Arcangeli Subject: Re: [PATCH] mmu notifiers #v3 Date: Tue, 22 Jan 2008 21:31:25 +0100 Message-ID: <20080122203125.GC15848@v2.random> References: <20080113162418.GE8736@v2.random> <20080116124256.44033d48@bree.surriel.com> <478E4356.7030303@qumranet.com> <20080117162302.GI7170@v2.random> <478F9C9C.7070500@qumranet.com> <20080117193252.GC24131@v2.random> <20080121125204.GJ6970@v2.random> <1201030127.6341.39.camel@lappy> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Andrew Morton , Nick Piggin , Benjamin Herrenschmidt , steiner-sJ/iWh9BUns@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Avi Kivity , linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, daniel.blueman-xqY44rlHlBpWk0Htik3J/w@public.gmane.org, holt-sJ/iWh9BUns@public.gmane.org, Hugh Dickins , clameter-sJ/iWh9BUns@public.gmane.org, kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org To: Peter Zijlstra Return-path: Content-Disposition: inline In-Reply-To: <1201030127.6341.39.camel@lappy> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org On Tue, Jan 22, 2008 at 08:28:47PM +0100, Peter Zijlstra wrote: > I think we can get rid of this rwlock as I think this will seriously > hurt larger machines. Yep, I initially considered it, nevertheless given you solved part of the complication I can add it now ;). The only technical reason for not using RCU is if certain users of the notifiers are registering and unregistering at high frequency through objects that may need to be freed quickly. I can tell the KVM usage of the mmu notifiers is sure fine to use RCU. Then I will have to update KVM so that it will free the kvm structure after waiting a quiescent point to avoid kernel crashing memory corruption after applying your changes to the mmu notifier. Thanks! ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/