Re: [Qemu-devel] [PATCH 3/8] migration: add new capability test-only

[Eric Blake <eblake@redhat.com>]

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On 10/07/2015 12:20 AM, Denis V. Lunev wrote:
> From: Igor Redko <redkoi@virtuozzo.com>
> 
> This patch declares a new migration capability that allows
> to distinguish between true migration and the test.
> 
> An alternative is using a custom URI but in this case the
> following problems should be solved:
> 1/ QEMUFile abstraction hides the real transport type
> 2/ We must be ensured that VM will not be stopped due to
> “successful migration”
> 
> Possible solutions:
> 1/ Using global variable analogous to
> s->enabled_capabilities[MIGRATION_CAPABILITY_TEST_ONLY] that
> will be initialized according to the migration type at the
> beginning of the migration process
> 2/ Additional hook, presence of implementation of which allows
> to decide whether the migration is true
> 

Do we want to name the capability 'x-test-only', since this series is
experimental, to make it obvious that production code should not rely on it?


> +++ b/qapi-schema.json
> @@ -540,11 +540,14 @@
>  # @auto-converge: If enabled, QEMU will automatically throttle down the guest
>  #          to speed up convergence of RAM migration. (since 1.6)
>  #
> +# @test-only: If enabled, QEMU instead of migrating will estimate migration
> +#          time basing on given downtime and current dirty page rate

If we do decide to add this to mainline, it would need 'since 2.5' (or
whatever version) documentation.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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