Re: [PATCH v8 10/12] migration/dirtyrate: Implement calculate_dirtyrate() function

[Li Qiang]

Chuan Zheng <zhengchuan@huawei.com> 于2020年9月14日周一 下午4:52写道：
>
> Implement calculate_dirtyrate() function.
>
> Signed-off-by: Chuan Zheng <zhengchuan@huawei.com>
> Signed-off-by: YanYing Zhuang <ann.zhuangyanying@huawei.com>
> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> ---
>  migration/dirtyrate.c | 45 +++++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 43 insertions(+), 2 deletions(-)
>
> diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c
> index 6add846..cc31bd1 100644
> --- a/migration/dirtyrate.c
> +++ b/migration/dirtyrate.c
> @@ -162,6 +162,21 @@ static void get_ramblock_dirty_info(RAMBlock *block,
>      strcpy(info->idstr, qemu_ram_get_idstr(block));
>  }
>
> +static void free_ramblock_dirty_info(struct RamblockDirtyInfo *infos, int 
> count)
> +{
> +    int i;
> +
> +    if (!infos) {
> +        return;
> +    }
> +
> +    for (i = 0; i < count; i++) {
> +        g_free(infos[i].sample_page_vfn);
> +        g_free(infos[i].hash_result);
> +    }
> +    g_free(infos);
> +}
> +
>  static bool skip_sample_ramblock(RAMBlock *block)
>  {
>      /*
> @@ -289,8 +304,34 @@ static int compare_page_hash_info(struct 
> RamblockDirtyInfo *info,
>
>  static void calculate_dirtyrate(struct DirtyRateConfig config)
>  {
> -    /* todo */
> -    return;
> +    struct RamblockDirtyInfo *block_dinfo = NULL;
> +    int block_index = 0;
> +    int64_t msec = 0;
> +    int64_t initial_time;
> +
> +    rcu_register_thread();
> +    reset_dirtyrate_stat();
> +    rcu_read_lock();
> +    initial_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
> +    if (!record_ramblock_hash_info(&block_dinfo, config, &block_index)) {
> +        goto out;
> +    }
> +    rcu_read_unlock();
> +
> +    msec = config.sample_period_seconds * 1000;
> +    msec = set_sample_page_period(msec, initial_time);
> +
> +    rcu_read_lock();
> +    if (compare_page_hash_info(block_dinfo, block_index) < 0) {
> +        goto out;

It seems the value of 'DirtyRateStat.dirty_rate'  is 0 if this error occurs ?

Maybe we should set the DirtyRateStat.dirty_rate to -1 in
reset_dirtyrate_stat function.
As you say:

+#          If this field return '-1', it means querying is not
+#          start or not complete.

The '0' may confuse the people there is no dirty page.

Thanks,
Li Qiang

> +    }
> +
> +    update_dirtyrate(msec);
> +
> +out:
> +    rcu_read_unlock();
> +    free_ramblock_dirty_info(block_dinfo, block_index);
> +    rcu_unregister_thread();
>  }
>
>  void *get_dirtyrate_thread(void *arg)
> --
> 1.8.3.1
>