From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeremy Fitzhardinge Subject: Re: [PATCH] Replace kvm io delay pv-ops with linux magic Date: Fri, 20 Nov 2009 10:08:27 +0800 Message-ID: <4B05FA1B.5000504@goop.org> References: <1258548984-32433-1-git-send-email-agraf@suse.de> <4B05CCEB.5050802@goop.org> <9466A245-8DB5-40FB-AE94-168117C2C692@suse.de> <4B05F6BD.3050402@goop.org> <38BE0E5F-E8E1-42BE-B406-5DA405BDBD56@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: kvm list , Nick Piggin , Glauber Costa , Avi Kivity , "virtualization@lists.linux-foundation.org" , Alok Kataria To: Alexander Graf Return-path: Received: from claw.goop.org ([74.207.240.146]:43508 "EHLO claw.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753962AbZKTCJG (ORCPT ); Thu, 19 Nov 2009 21:09:06 -0500 In-Reply-To: <38BE0E5F-E8E1-42BE-B406-5DA405BDBD56@suse.de> Sender: kvm-owner@vger.kernel.org List-ID: On 11/20/09 09:59, Alexander Graf wrote: > > On 20.11.2009, at 02:54, Jeremy Fitzhardinge wrote: > >> On 11/20/09 07:58, Alexander Graf wrote: >>> >>> Am 19.11.2009 um 23:55 schrieb Jeremy Fitzhardinge : >>> >>>> On 11/18/09 20:56, Alexander Graf wrote: >>>>> Currently we use pv-ops to tell linux not to do anything on io_delay. >>>>> >>>>> While the basic idea is good IMHO, I don't see why we would need >>>>> pv-ops >>>>> for that. The io delay function already has a switch that can do >>>>> nothing >>>>> if you're so inclined. >>>>> >>>>> So here's a patch (stacked on top of the previous pv-ops series) that >>>>> removes the io delay pv-ops hook and just sets the native io delay >>>>> variable instead. >>>>> >>>> >>>> Can you just get rid of the io_delay op altogether? If KVM doesn't >>>> need >>>> it, then nobody does. >>> >>> Sure, can do. That'd be a separate patch though. >> >> Yep. A patch each for VMI and Xen to remove the dependency, and a final >> patch to remove the op. Hm, looks like VMI has a specific ROM call for >> io_delay; I wonder what it does. > > Oh so it's actually using it? Feel like doing the removal then? I > don't really want to mess with VMI code :-) I would post the patch and see if Alok naks it. But I somehow doubt vmware is doing anything profound with that call. J