Re: [PATCH v9 08/12] migration/dirtyrate: skip sampling ramblock with size below MIN_RAMBLOCK_SIZE

[Li Qiang]

Chuan Zheng <zhengchuan@huawei.com> 于2020年9月15日周二 上午10:34写道：
>
> In order to sample real RAM, skip ramblock with size below MIN_RAMBLOCK_SIZE
> which is set as 128M.
>
> Signed-off-by: Chuan Zheng <zhengchuan@huawei.com>
> Reviewed-by: David Edmondson <david.edmondson@oracle.com>
> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

Reviewed-by: Li Qiang <liq3ea@gmail.com>
> ---
>  migration/dirtyrate.c | 21 +++++++++++++++++++++
>  migration/dirtyrate.h |  5 +++++
>  2 files changed, 26 insertions(+)
>
> diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c
> index 2d48eb8..903f728 100644
> --- a/migration/dirtyrate.c
> +++ b/migration/dirtyrate.c
> @@ -138,6 +138,18 @@ static void get_ramblock_dirty_info(RAMBlock *block,
>      strcpy(info->idstr, qemu_ram_get_idstr(block));
>  }
>
> +static bool skip_sample_ramblock(RAMBlock *block)
> +{
> +    /*
> +     * Sample only blocks larger than MIN_RAMBLOCK_SIZE.
> +     */
> +    if (qemu_ram_get_used_length(block) < (MIN_RAMBLOCK_SIZE << 10)) {
> +        return true;
> +    }
> +
> +    return false;
> +}
> +
>  static bool record_ramblock_hash_info(struct RamblockDirtyInfo **block_dinfo,
>                                        struct DirtyRateConfig config,
>                                        int *block_count)
> @@ -150,6 +162,9 @@ static bool record_ramblock_hash_info(struct 
> RamblockDirtyInfo **block_dinfo,
>      bool ret = false;
>
>      RAMBLOCK_FOREACH_MIGRATABLE(block) {
> +        if (skip_sample_ramblock(block)) {
> +            continue;
> +        }
>          total_count++;
>      }
>
> @@ -159,6 +174,9 @@ static bool record_ramblock_hash_info(struct 
> RamblockDirtyInfo **block_dinfo,
>      }
>
>      RAMBLOCK_FOREACH_MIGRATABLE(block) {
> +        if (skip_sample_ramblock(block)) {
> +            continue;
> +        }
>          if (index >= total_count) {
>              break;
>          }
> @@ -225,6 +243,9 @@ static bool compare_page_hash_info(struct 
> RamblockDirtyInfo *info,
>      RAMBlock *block = NULL;
>
>      RAMBLOCK_FOREACH_MIGRATABLE(block) {
> +        if (skip_sample_ramblock(block)) {
> +            continue;
> +        }
>          block_dinfo = find_page_matched(block, block_count, info);
>          if (block_dinfo == NULL) {
>              continue;
> diff --git a/migration/dirtyrate.h b/migration/dirtyrate.h
> index a3ee305..faaf9da 100644
> --- a/migration/dirtyrate.h
> +++ b/migration/dirtyrate.h
> @@ -24,6 +24,11 @@
>   */
>  #define RAMBLOCK_INFO_MAX_LEN                     256
>
> +/*
> + * Minimum RAMBlock size to sample, in megabytes.
> + */
> +#define MIN_RAMBLOCK_SIZE                         128
> +
>  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
>