[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH v5 38/45] Don't sync dirty bitmaps in postcopy
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [PATCH v5 38/45] Don't sync dirty bitmaps in postcopy |
Date: |
Tue, 24 Mar 2015 09:05:20 +0000 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
* David Gibson (address@hidden) wrote:
> On Wed, Feb 25, 2015 at 04:52:01PM +0000, Dr. David Alan Gilbert (git) wrote:
> > From: "Dr. David Alan Gilbert" <address@hidden>
> >
> > Once we're in postcopy the source processors are stopped and memory
> > shouldn't change any more, so there's no need to look at the dirty
> > map.
> >
> > There are two notes to this:
> > 1) If we do resync and a page had changed then the page would get
> > sent again, which the destination wouldn't allow (since it might
> > have also modified the page)
>
> I'm not quite sure what you mean by "resync" in this context.
I mean synchronise the raw dirty bitmap with the migration bitmap,
which we normally do at every cycle through migration.
> > 2) Before disabling this I'd seen very rare cases where a page had been
> > marked dirtied although the memory contents are apparently identical
> >
> > Signed-off-by: Dr. David Alan Gilbert <address@hidden>
>
> Reviewed-by: David Gibson <address@hidden>
Thanks,
Dave
>
> --
> David Gibson | I'll have my music baroque, and my code
> david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_
> _other_
> | _way_ _around_!
> http://www.ozlabs.org/~dgibson
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK