Re: [PATCH v3 06/10] migration/dirtyrate: Compare page hash results for recorded sampled page

[Dr. David Alan Gilbert]

* Chuan Zheng (zhengchuan@huawei.com) wrote:
> Compare page hash results for recorded sampled page.
> 
> Signed-off-by: Chuan Zheng <zhengchuan@huawei.com>
> Signed-off-by: YanYing Zhuang <ann.zhuangyanying@huawei.com>
> ---
>  migration/dirtyrate.c | 76 
> +++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 76 insertions(+)
> 
> diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c
> index 62b6f69..3ce25f5 100644
> --- a/migration/dirtyrate.c
> +++ b/migration/dirtyrate.c
> @@ -215,6 +215,82 @@ static int record_ramblock_hash_info(struct 
> RamblockDirtyInfo **block_dinfo,
>      return 0;
>  }
>  
> +static int calc_page_dirty_rate(struct RamblockDirtyInfo *info)
> +{
> +    uint8_t *md = NULL;
> +    int i;
> +    int ret = 0;
> +
> +    md = g_try_new0(uint8_t, qcrypto_hash_len);
> +    if (!md) {
> +        return -1;
> +    }

As previously asked; isn't this a nice small simple fixed length - no
need to allocate it?

> +
> +    for (i = 0; i < info->sample_pages_count; i++) {
> +        ret = get_ramblock_vfn_hash(info, info->sample_page_vfn[i], &md);
> +        if (ret < 0) {
> +            goto out;
> +        }
> +
> +        if (memcmp(md, info->hash_result + i * qcrypto_hash_len,
> +                   qcrypto_hash_len) != 0) {
> +            info->sample_dirty_count++;
> +        }
> +    }
> +
> +out:
> +    g_free(md);
> +    return ret;
> +}
> +
> +static bool find_page_matched(RAMBlock *block, struct RamblockDirtyInfo 
> *infos,
> +                              int count, struct RamblockDirtyInfo **matched)
> +{
> +    int i;
> +
> +    for (i = 0; i < count; i++) {
> +        if (!strcmp(infos[i].idstr, qemu_ram_get_idstr(block))) {
> +            break;
> +        }
> +    }
> +
> +    if (i == count) {
> +        return false;
> +    }
> +
> +    if (infos[i].ramblock_addr != qemu_ram_get_host_addr(block) ||
> +        infos[i].ramblock_pages !=
> +            (qemu_ram_get_used_length(block) >> 12)) {
> +        return false;

I previously asked how this happens.
Also this was DIRTYRATE_PAGE_SIZE_SHIFT

> +    }
> +
> +    *matched = &infos[i];
> +    return true;
> +}
> +
> +static int compare_page_hash_info(struct RamblockDirtyInfo *info,
> +                                  int block_index)
> +{
> +    struct RamblockDirtyInfo *block_dinfo = NULL;
> +    RAMBlock *block = NULL;
> +
> +    RAMBLOCK_FOREACH_MIGRATABLE(block) {
> +        block_dinfo = NULL;

So you've removed the selction of only some RAMBlocks now?

> +        if (!find_page_matched(block, info, block_index + 1, &block_dinfo)) {
> +            continue;
> +        }
> +        if (calc_page_dirty_rate(block_dinfo) < 0) {
> +            return -1;
> +        }
> +        update_dirtyrate_stat(block_dinfo);
> +    }
> +    if (!dirty_stat.total_sample_count) {
> +        return -1;
> +    }
> +
> +    return 0;
> +}
> +
>  static void calculate_dirtyrate(struct DirtyRateConfig config)
>  {
>      /* todo */
> -- 
> 1.8.3.1
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK