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Re: [Qemu-devel] [RFC Design Doc]Speed up live migration by skipping fre
Michael S. Tsirkin
Re: [Qemu-devel] [RFC Design Doc]Speed up live migration by skipping free pages
Mon, 18 Apr 2016 14:29:25 +0300
On Mon, Apr 18, 2016 at 11:08:31AM +0000, Li, Liang Z wrote:
> Hi Dave,
> I am now working on how to benefit post-copy by skipping the free pages,
> and I remember you have said we should let the destination know the info
> of free pages so as to avoid request the free pages from the source.
> We have two solutions:
> a. send the migration dirty page bitmap to destination before post
> copy start, so the destination can decide whether to request the pages or
> place zero pages by checking the migration dirty page bitmap. The advantage
> is that we can avoid sending the free pages. the disadvantage is that we have
> to send extra data to destination.
> b. Check the page request on the source side, if it's not a dirty page, send
> a zero
> page header to the destination.
> What's your opinion about them?
Both are ad-hoc solutions imho.
c. put the bitmap in a ramblock, check it on destination before
This way it's migrated on-demand.