Re: [PATCH v6 08/12] migration/dirtyrate: skip sampling ramblock with size below MIN_RAMBLOCK_SIZE

[David Edmondson]

On Saturday, 2020-08-29 at 10:52:53 +08, Chuan Zheng wrote:

> 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>

Minor wordsmithing below, but...

Reviewed-by: David Edmondson <david.edmondson@oracle.com>

> ---
>  migration/dirtyrate.c | 19 +++++++++++++++++++
>  migration/dirtyrate.h |  5 +++++
>  2 files changed, 24 insertions(+)
>
> diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c
> index 9cc2cbb..420fc59 100644
> --- a/migration/dirtyrate.c
> +++ b/migration/dirtyrate.c
> @@ -164,6 +164,19 @@ alloc_ramblock_dirty_info(int *block_index,
>      return block_dinfo;
>  }
>  
> +static bool skip_sample_ramblock(RAMBlock *block)
> +{
> +    /*
> +     * Consider ramblock with size larger than 128M is what we
> +     * want to sample.

"Sample only blocks larger than MIN_RAMBLOCK_SIZE."

> +     */
> +    if (qemu_ram_get_used_length(block) < (MIN_RAMBLOCK_SIZE << 10)) {
> +        return true;
> +    }
> +
> +    return false;
> +}
> +
>  static int record_ramblock_hash_info(struct RamblockDirtyInfo **block_dinfo,
>                                       struct DirtyRateConfig config,
>                                       int *block_index)
> @@ -174,6 +187,9 @@ static int record_ramblock_hash_info(struct 
> RamblockDirtyInfo **block_dinfo,
>      int index = 0;
>  
>      RAMBLOCK_FOREACH_MIGRATABLE(block) {
> +        if (skip_sample_ramblock(block)) {
> +            continue;
> +        }
>          dinfo = alloc_ramblock_dirty_info(&index, dinfo);
>          if (dinfo == NULL) {
>              return -1;
> @@ -241,6 +257,9 @@ static int 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_index + 1, 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

dme.
-- 
Jane was in her turtle neck, I was much happier then.