Re: [Qemu-devel] [RFC PATCH RDMA support v1: 10/13] introduce new command migrate_check_for_zero

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Apr 10, 2013 at 06:28:18PM -0400, mrhines@linux.vnet.ibm.com wrote:
> From: "Michael R. Hines" <mrhines@us.ibm.com>
> 
> This allows the user to disable zero page checking during migration
> 
> Signed-off-by: Michael R. Hines <mrhines@us.ibm.com>

IMO this knob is too low level to expose to management.
Why not disable this automatically when migrating with rdma?

> ---
>  hmp-commands.hx  |   14 ++++++++++++++
>  hmp.c            |    6 ++++++
>  hmp.h            |    1 +
>  migration.c      |   12 ++++++++++++
>  qapi-schema.json |   13 +++++++++++++
>  qmp-commands.hx  |   23 +++++++++++++++++++++++
>  6 files changed, 69 insertions(+)
> 
> diff --git a/hmp-commands.hx b/hmp-commands.hx
> index 3d98604..b593095 100644
> --- a/hmp-commands.hx
> +++ b/hmp-commands.hx
> @@ -962,6 +962,20 @@ Set maximum tolerated downtime (in seconds) for migration.
>  ETEXI
>  
>      {
> +        .name       = "migrate_check_for_zero",
> +        .args_type  = "value:b",
> +        .params     = "value",
> +        .help       = "Control whether or not to check for zero pages",
> +        .mhandler.cmd = hmp_migrate_check_for_zero,
> +    },
> +
> +STEXI
> +@item migrate_check_for_zero @var{value}
> +@findex migrate_check_for_zero
> +Control whether or not to check for zero pages.
> +ETEXI
> +
> +    {
>          .name       = "migrate_set_capability",
>          .args_type  = "capability:s,state:b",
>          .params     = "capability state",
> diff --git a/hmp.c b/hmp.c
> index dbe9b90..68ba93a 100644
> --- a/hmp.c
> +++ b/hmp.c
> @@ -909,6 +909,12 @@ void hmp_migrate_set_downtime(Monitor *mon, const QDict *qdict)
>      qmp_migrate_set_downtime(value, NULL);
>  }
>  
> +void hmp_migrate_check_for_zero(Monitor *mon, const QDict *qdict)
> +{
> +    bool value = qdict_get_bool(qdict, "value");
> +    qmp_migrate_check_for_zero(value, NULL);
> +}
> +
>  void hmp_migrate_set_cache_size(Monitor *mon, const QDict *qdict)
>  {
>      int64_t value = qdict_get_int(qdict, "value");
> diff --git a/hmp.h b/hmp.h
> index 80e8b41..a6595da 100644
> --- a/hmp.h
> +++ b/hmp.h
> @@ -58,6 +58,7 @@ void hmp_snapshot_blkdev(Monitor *mon, const QDict *qdict);
>  void hmp_drive_mirror(Monitor *mon, const QDict *qdict);
>  void hmp_migrate_cancel(Monitor *mon, const QDict *qdict);
>  void hmp_migrate_set_downtime(Monitor *mon, const QDict *qdict);
> +void hmp_migrate_check_for_zero(Monitor *mon, const QDict *qdict);
>  void hmp_migrate_set_speed(Monitor *mon, const QDict *qdict);
>  void hmp_migrate_set_capability(Monitor *mon, const QDict *qdict);
>  void hmp_migrate_set_cache_size(Monitor *mon, const QDict *qdict);
> diff --git a/migration.c b/migration.c
> index a2fcacf..9072479 100644
> --- a/migration.c
> +++ b/migration.c
> @@ -485,6 +485,18 @@ void qmp_migrate_set_downtime(double value, Error **errp)
>      max_downtime = (uint64_t)value;
>  }
>  
> +static bool check_for_zero = true;
> +
> +void qmp_migrate_check_for_zero(bool value, Error **errp)
> +{
> +    check_for_zero = value;
> +}
> +
> +bool migrate_check_for_zero(void)
> +{
> +    return check_for_zero;
> +}
> +
>  bool migrate_chunk_register_destination(void)
>  {
>      MigrationState *s;
> diff --git a/qapi-schema.json b/qapi-schema.json
> index 7fe7e5c..1ca939f 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -1792,6 +1792,19 @@
>  { 'command': 'migrate_set_downtime', 'data': {'value': 'number'} }
>  
>  ##
> +# @migrate_check_for_zero
> +#
> +# Control whether or not to check for zero pages during migration.
> +#
> +# @value: on|off 
> +#
> +# Returns: nothing on success
> +#
> +# Since: 1.5.0
> +##
> +{ 'command': 'migrate_check_for_zero', 'data': {'value': 'bool'} }
> +
> +##
>  # @migrate_set_speed
>  #
>  # Set maximum speed for migration.
> diff --git a/qmp-commands.hx b/qmp-commands.hx
> index 1e0e11e..78cda67 100644
> --- a/qmp-commands.hx
> +++ b/qmp-commands.hx
> @@ -750,6 +750,29 @@ Example:
>  EQMP
>  
>      {
> +        .name       = "migrate_check_for_zero",
> +        .args_type  = "value:b",
> +        .mhandler.cmd_new = qmp_marshal_input_migrate_check_for_zero,
> +    },
> +
> +SQMP
> +migrate_check_for_zero
> +----------------------
> +
> +Control whether or not to check for zero pages.
> +
> +Arguments:
> +
> +- "value": true or false (json-bool) 
> +
> +Example:
> +
> +-> { "execute": "migrate_check_for_zero", "arguments": { "value": true } }
> +<- { "return": {} }
> +
> +EQMP
> +
> +    {
>          .name       = "client_migrate_info",
>          .args_type  = "protocol:s,hostname:s,port:i?,tls-port:i?,cert-subject:s?",
>          .params     = "protocol hostname port tls-port cert-subject",
> -- 
> 1.7.10.4