Re: [PATCH v7 02/12] migration/dirtyrate: add DirtyRateStatus to denote calculation status

[Li Qiang]

Chuan Zheng <zhengchuan@huawei.com> 于2020年9月9日周三 下午10:08写道：
>
> add DirtyRateStatus to denote calculating status.
>
> Signed-off-by: Chuan Zheng <zhengchuan@huawei.com>
> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> ---
>  migration/dirtyrate.c | 22 ++++++++++++++++++++++
>  qapi/migration.json   | 17 +++++++++++++++++
>  2 files changed, 39 insertions(+)
>
> diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c
> index bf7fd24..0a3350a 100644
> --- a/migration/dirtyrate.c
> +++ b/migration/dirtyrate.c
> @@ -22,6 +22,19 @@
>  #include "migration.h"
>  #include "dirtyrate.h"
>
> +static int CalculatingState = DIRTY_RATE_STATUS_UNSTARTED;
> +
> +static int dirtyrate_set_state(int *state, int old_state, int new_state)
> +{
> +    assert(new_state < DIRTY_RATE_STATUS__MAX);
> +    if (atomic_cmpxchg(state, old_state, new_state) == old_state) {
> +        return 0;
> +    } else {
> +        return -1;
> +    }
> +}
> +
> +
>  static void calculate_dirtyrate(struct DirtyRateConfig config)
>  {
>      /* todo */
> @@ -31,8 +44,17 @@ static void calculate_dirtyrate(struct DirtyRateConfig 
> config)
>  void *get_dirtyrate_thread(void *arg)
>  {
>      struct DirtyRateConfig config = *(struct DirtyRateConfig *)arg;
> +    int ret;
> +
> +    ret = dirtyrate_set_state(&CalculatingState, DIRTY_RATE_STATUS_UNSTARTED,
> +                              DIRTY_RATE_STATUS_MEASURING);
> +    if (ret == -1) {
> +        return NULL;
> +    }
>
>      calculate_dirtyrate(config);
>
> +    ret = dirtyrate_set_state(&CalculatingState, DIRTY_RATE_STATUS_MEASURING,
> +                              DIRTY_RATE_STATUS_MEASURED);

Doesn't need to check the 'ret'?
Just curious you checked other places but not here.

Thanks,
Li Qiang

>      return NULL;
>  }
> diff --git a/qapi/migration.json b/qapi/migration.json
> index 5f6b061..061ff25 100644
> --- a/qapi/migration.json
> +++ b/qapi/migration.json
> @@ -1720,3 +1720,20 @@
>  ##
>  { 'event': 'UNPLUG_PRIMARY',
>    'data': { 'device-id': 'str' } }
> +
> +##
> +# @DirtyRateStatus:
> +#
> +# An enumeration of dirtyrate status.
> +#
> +# @unstarted: the dirtyrate thread has not been started.
> +#
> +# @measuring: the dirtyrate thread is measuring.
> +#
> +# @measured: the dirtyrate thread has measured and results are available.
> +#
> +# Since: 5.2
> +#
> +##
> +{ 'enum': 'DirtyRateStatus',
> +  'data': [ 'unstarted', 'measuring', 'measured'] }
> --
> 1.8.3.1
>
>