Re: [PATCH v7 09/12] migration/dirtyrate: Implement set_sample_page_period() and get_sample_page_period()

[Zheng Chuan]

On 2020/9/10 21:59, Li Qiang wrote:
> Chuan Zheng <zhengchuan@huawei.com> 于2020年9月9日周三 下午10:15写道：
>>
>> Implement set_sample_page_period()/get_sample_page_period() to sleep
>> specific time between sample actions.
>>
>> Signed-off-by: Chuan Zheng <zhengchuan@huawei.com>
>> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
>> Reviewed-by: David Edmondson <david.edmondson@oracle.com>
>> ---
>>  migration/dirtyrate.c | 24 ++++++++++++++++++++++++
>>  migration/dirtyrate.h |  6 ++++++
>>  2 files changed, 30 insertions(+)
>>
>> diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c
>> index ae1959b..8a30261 100644
>> --- a/migration/dirtyrate.c
>> +++ b/migration/dirtyrate.c
>> @@ -27,6 +27,30 @@
>>  static int CalculatingState = DIRTY_RATE_STATUS_UNSTARTED;
>>  static struct DirtyRateStat DirtyStat;
>>
>> +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 bool get_sample_page_period(int64_t sec)
> 
> 
> This function name may confuse people the this will get the period.
> But in fact you just check whether the 'period' is valid.
> I think it is better to name it to be 'is_sample_period_valid' or
> something meaningful.
> 
> Thanks,
> Li Qiang
> 
Sure, will optimize it in later patch update.

>> +{
>> +    if (sec < MIN_FETCH_DIRTYRATE_TIME_SEC ||
>> +        sec > MAX_FETCH_DIRTYRATE_TIME_SEC) {
>> +        return false;
>> +    }
>> +
>> +    return true;
>> +}
>> +
>>  static int dirtyrate_set_state(int *state, int old_state, int new_state)
>>  {
>>      assert(new_state < DIRTY_RATE_STATUS__MAX);
>> diff --git a/migration/dirtyrate.h b/migration/dirtyrate.h
>> index faaf9da..8f9bc80 100644
>> --- a/migration/dirtyrate.h
>> +++ b/migration/dirtyrate.h
>> @@ -29,6 +29,12 @@
>>   */
>>  #define MIN_RAMBLOCK_SIZE                         128
>>
>> +/*
>> + * Take 1s as minimum time for calculation duration
>> + */
>> +#define MIN_FETCH_DIRTYRATE_TIME_SEC              1
>> +#define MAX_FETCH_DIRTYRATE_TIME_SEC              60
>> +
>>  struct DirtyRateConfig {
>>      uint64_t sample_pages_per_gigabytes; /* sample pages per GB */
>>      int64_t sample_period_seconds; /* time duration between two sampling */
>> --
>> 1.8.3.1
>>
>>
> 
> .
>