Re: [External] Re: [PATCH v2 1/7] migration/multifd: Add new migration option zero-page-detection.

[Hao Xiang]

On Wed, Feb 21, 2024 at 4:03 AM Markus Armbruster <armbru@redhat.com> wrote:
>
> Hao Xiang <hao.xiang@bytedance.com> writes:
>
> > This new parameter controls where the zero page checking is running.
> > 1. If this parameter is set to 'legacy', zero page checking is
> > done in the migration main thread.
> > 2. If this parameter is set to 'none', zero page checking is disabled.
> >
> > Signed-off-by: Hao Xiang <hao.xiang@bytedance.com>
>
> [...]
>
> > diff --git a/qapi/migration.json b/qapi/migration.json
> > index 5a565d9b8d..99843a8e95 100644
> > --- a/qapi/migration.json
> > +++ b/qapi/migration.json
> > @@ -653,6 +653,17 @@
> >  { 'enum': 'MigMode',
> >    'data': [ 'normal', 'cpr-reboot' ] }
> >
> > +##
> > +# @ZeroPageDetection:
> > +#
> > +# @legacy: Perform zero page checking from main migration thread. (since 
> > 9.0)
> > +#
> > +# @none: Do not perform zero page checking.
> > +#
> > +##
>
> The entire type is since 9.0.  Thus:
>
>    ##
>    # @ZeroPageDetection:
>    #
>    # @legacy: Perform zero page checking from main migration thread.
>    #
>    # @none: Do not perform zero page checking.
>    #
>    # Since: 9.0
>    ##
>
> > +{ 'enum': 'ZeroPageDetection',
> > +  'data': [ 'legacy', 'none' ] }
> > +
> >  ##
> >  # @BitmapMigrationBitmapAliasTransform:
> >  #
> > @@ -874,6 +885,9 @@
> >  # @mode: Migration mode. See description in @MigMode. Default is 'normal'.
> >  #        (Since 8.2)
> >  #
> > +# @zero-page-detection: See description in @ZeroPageDetection.
> > +#     Default is 'legacy'. (Since 9.0)
>
> The description feels a bit lazy :)
>
> Suggest
>
>    # @zero-page-detection: Whether and how to detect zero pages.  Default
>    #     is 'legacy'.  (since 9.0)
>
> Same for the other two copies.

I will fix these in the next version.

>
> > +#
> >  # Features:
> >  #
> >  # @deprecated: Member @block-incremental is deprecated.  Use
> > @@ -907,7 +921,8 @@
> >             'block-bitmap-mapping',
> >             { 'name': 'x-vcpu-dirty-limit-period', 'features': ['unstable'] 
> > },
> >             'vcpu-dirty-limit',
> > -           'mode'] }
> > +           'mode',
> > +           'zero-page-detection'] }
> >
> >  ##
> >  # @MigrateSetParameters:
> > @@ -1066,6 +1081,10 @@
> >  # @mode: Migration mode. See description in @MigMode. Default is 'normal'.
> >  #        (Since 8.2)
> >  #
> > +# @zero-page-detection: See description in @ZeroPageDetection.
> > +#     Default is 'legacy'. (Since 9.0)
> > +#
> > +#
> >  # Features:
> >  #
> >  # @deprecated: Member @block-incremental is deprecated.  Use
> > @@ -1119,7 +1138,8 @@
> >              '*x-vcpu-dirty-limit-period': { 'type': 'uint64',
> >                                              'features': [ 'unstable' ] },
> >              '*vcpu-dirty-limit': 'uint64',
> > -            '*mode': 'MigMode'} }
> > +            '*mode': 'MigMode',
> > +            '*zero-page-detection': 'ZeroPageDetection'} }
> >
> >  ##
> >  # @migrate-set-parameters:
> > @@ -1294,6 +1314,9 @@
> >  # @mode: Migration mode. See description in @MigMode. Default is 'normal'.
> >  #        (Since 8.2)
> >  #
> > +# @zero-page-detection: See description in @ZeroPageDetection.
> > +#     Default is 'legacy'. (Since 9.0)
> > +#
> >  # Features:
> >  #
> >  # @deprecated: Member @block-incremental is deprecated.  Use
> > @@ -1344,7 +1367,8 @@
> >              '*x-vcpu-dirty-limit-period': { 'type': 'uint64',
> >                                              'features': [ 'unstable' ] },
> >              '*vcpu-dirty-limit': 'uint64',
> > -            '*mode': 'MigMode'} }
> > +            '*mode': 'MigMode',
> > +            '*zero-page-detection': 'ZeroPageDetection'} }
> >
> >  ##
> >  # @query-migrate-parameters:
>