Re: [PATCH v3 08/10] migration/dirtyrate: Implement get_sample_page_period() and block_sample_page_period()

[Dr. David Alan Gilbert]

* Chuan Zheng (zhengchuan@huawei.com) wrote:
> Implement get_sample_page_period() and set_sample_page_period() to
> sleep specific time between sample actions.
> 
> Signed-off-by: Chuan Zheng <zhengchuan@huawei.com>
> Signed-off-by: YanYing Zhuang <ann.zhuangyanying@huawei.com>
> ---
>  migration/dirtyrate.c | 24 ++++++++++++++++++++++++
>  migration/dirtyrate.h |  2 ++
>  2 files changed, 26 insertions(+)
> 
> diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c
> index 6f30f67..4bbfcc3 100644
> --- a/migration/dirtyrate.c
> +++ b/migration/dirtyrate.c
> @@ -28,6 +28,30 @@ CalculatingDirtyRateState CalculatingState = 
> CAL_DIRTY_RATE_INIT;
>  static unsigned long int qcrypto_hash_len = QCRYPTO_HASH_LEN;
>  static struct DirtyRateStat dirty_stat;
>  
> +static int64_t set_sample_page_period(int64_t msec, int64_t initial_time)
> +{
> +    int64_t current_time;
> +
> +    current_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
> +    if ((current_time - initial_time) >= msec) {
> +        msec = current_time - initial_time;
> +    } else {
> +        g_usleep((msec + initial_time - current_time) * 1000);
> +    }
> +
> +    return msec;
> +}
> +
> +static int64_t get_sample_page_period(int64_t sec)
> +{
> +    if (sec <= MIN_FETCH_DIRTYRATE_TIME_SEC ||
> +        sec > MAX_FETCH_DIRTYRATE_TIME_SEC) {
> +        sec = DEFAULT_FETCH_DIRTYRATE_TIME_SEC;
> +    }
> +
> +    return sec;
> +}
> +

This is OK I think, but it does seem a bit complicated for just
waiting for a time.


Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

>  static int dirty_rate_set_state(int new_state)
>  {
>      int old_state = CalculatingState;
> diff --git a/migration/dirtyrate.h b/migration/dirtyrate.h
> index fce2e3b..86d8fa0 100644
> --- a/migration/dirtyrate.h
> +++ b/migration/dirtyrate.h
> @@ -38,6 +38,8 @@
>  
>  /* Take 1s as default for calculation duration */
>  #define DEFAULT_FETCH_DIRTYRATE_TIME_SEC          1
> +#define MIN_FETCH_DIRTYRATE_TIME_SEC              0
> +#define MAX_FETCH_DIRTYRATE_TIME_SEC              60
>  
>  struct DirtyRateConfig {
>      uint64_t sample_pages_per_gigabytes; /* sample pages per GB */
> -- 
> 1.8.3.1
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK