Re: [PATCH v4 3/3] multifd: Implement zerocopy write in multifd migration (multifd-zerocopy)

[Peter Xu]

On Sat, Oct 09, 2021 at 04:56:13AM -0300, Leonardo Bras wrote:
> diff --git a/qapi/migration.json b/qapi/migration.json
> index 88f07baedd..c4890cbb54 100644
> --- a/qapi/migration.json
> +++ b/qapi/migration.json
> @@ -724,6 +724,11 @@
>  #                      will consume more CPU.
>  #                      Defaults to 1. (Since 5.0)
>  #
> +# @multifd-zerocopy: Controls behavior on sending memory pages on multifd 
> migration.
> +#                    When true, enables a zerocopy mechanism for sending 
> memory
> +#                    pages, if host does support it.
> +#                    Defaults to false. (Since 6.2)
> +#

Shall we keep it named "@zerocopy"?  Yes we have that dependency with multifd,
but it's fine to just fail the configuration if multifd not set. The thing is
we don't know whether that dependency will last forever, and we probably don't
want to introduce yet another feature bit when we can remove the dependency..
as we can't remove the old one to be compatible.

-- 
Peter Xu