Re: [RFC PATCH 1/6] migration: Add multi-thread compress method

[Eric Blake]

On 11/9/20 3:08 AM, Zeyu Jin wrote:
> A multi-thread compress method parameter is added to hold the method we
> are going to use. By default the 'zlib' method is used to maintain the
> compatibility as before.
> 
> Signed-off-by: Zeyu Jin <jinzeyu@huawei.com>
> Signed-off-by: Ying Fang <fangying1@huawei.com>
> ---

Focusing on just the UI:

> +++ b/qapi/migration.json
> @@ -525,6 +525,19 @@
>    'data': [ 'none', 'zlib',
>              { 'name': 'zstd', 'if': 'defined(CONFIG_ZSTD)' } ] }
>  
> +##
> +# @CompressMethod:
> +#
> +# An enumeration of multi-thread compression methods.
> +#
> +# @zlib: use zlib compression method.
> +#
> +# Since: 5.0

This will have to be Since: 6.0, as it has missed feature freeze for 5.2.

> +#
> +##
> +{ 'enum': 'CompressMethod',
> +  'data': [ 'zlib' ] }
> +
>  ##
>  # @BitmapMigrationBitmapAlias:
>  #
> @@ -599,6 +612,9 @@
>  #                      compression, so set the decompress-threads to the 
> number about 1/4
>  #                      of compress-threads is adequate.
>  #
> +# @compress-method: Set compression method to use in multi-thread 
> compression.
> +#                   Defaults to none. (Since 5.0)

Looks like it will be a recurring issue in the series, so I'll quit
pointing it out.

CompressMethod above does not have a 'none' option, so how can it
default to none?  Did you forget an enum option?

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org