From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from [140.186.70.92] (port=35704 helo=eggs.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43) id 1Q7hw0-0003IT-Vv
	for qemu-devel@nongnu.org; Thu, 07 Apr 2011 01:39:13 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <bradh@frogmouth.net>) id 1Q7hvz-0004G6-An
	for qemu-devel@nongnu.org; Thu, 07 Apr 2011 01:39:12 -0400
Received: from ipmail07.adl2.internode.on.net ([150.101.137.131]:48684)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <bradh@frogmouth.net>) id 1Q7hvy-0004F0-WB
	for qemu-devel@nongnu.org; Thu, 07 Apr 2011 01:39:11 -0400
From: Brad Hards <bradh@frogmouth.net>
Subject: Re: [Qemu-devel] [PATCH RFC 0/5] kvm/vhost: enable durty logging
	during memory registration
Date: Thu, 7 Apr 2011 15:39:04 +1000
References: <cover.1302121974.git.mst@redhat.com>
In-Reply-To: <cover.1302121974.git.mst@redhat.com>
MIME-Version: 1.0
Content-Type: Text/Plain;
  charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
Message-Id: <201104071539.04904.bradh@frogmouth.net>
List-Id: qemu-devel.nongnu.org
List-Unsubscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: qemu-devel@nongnu.org
Cc: "Michael S. Tsirkin" <mst@redhat.com>

On Thu, 7 Apr 2011 06:41:35 am Michael S. Tsirkin wrote:
> As a solution, this adds an explicit flag that
> will enable dirty logging directly when registering
> the ram. kvm then needs a single system call
> to update tables for vga ram, vhost-net can simply ignore it.
I'm not very familiar with QEMU coding style and standards (so this could be 
completely bogus), but I think that the code would be easier if you used a 
integer flag / enum instead of a boolean. That would also give you options for 
additional behaviour changes later too. So instead of passing true/false, pass 
MEM_LOG_DIRTY_PAGES (or whatever you decide to call it).

I can't really comment on the rest of the patch - I'm too clueless. 

> This replaces the RFC patchset 'vga: flag vga ram for notifiers'.
> Warning: compile-tested only.
I compiled and booted my Ubuntu guest (on ubuntu host) which uses Cirrus for 
each step in this patchset. Seems OK to me - I didn't notice appreciable 
speedup, but I wasn't really expecting to.

Brad