Re: [PATCH v8 06/12] migration/dirtyrate: Record hash results for each sampled page

[Zheng Chuan]

On 2020/9/14 22:59, Li Qiang wrote:
> Chuan Zheng <zhengchuan@huawei.com> 于2020年9月14日周一 下午4:52写道：
>>
>> Record hash results for each sampled page, crc32 is taken to calculate
>> hash results for each sampled length in TARGET_PAGE_SIZE.
>>
>> Signed-off-by: Chuan Zheng <zhengchuan@huawei.com>
>> Signed-off-by: YanYing Zhuang <ann.zhuangyanying@huawei.com>
>> Reviewed-by: David Edmondson <david.edmondson@oracle.com>
>> ---
>>  migration/dirtyrate.c | 111 
>> ++++++++++++++++++++++++++++++++++++++++++++++++++
>>  1 file changed, 111 insertions(+)
>>
>> diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c
>> index cf2d560..beb18cb 100644
>> --- a/migration/dirtyrate.c
>> +++ b/migration/dirtyrate.c
>> @@ -10,6 +10,7 @@
>>   * See the COPYING file in the top-level directory.
>>   */
>>
>> +#include <zlib.h>
>>  #include "qemu/osdep.h"
>>  #include "qapi/error.h"
>>  #include "cpu.h"
>> @@ -68,6 +69,116 @@ static void update_dirtyrate(uint64_t msec)
>>      DirtyStat.dirty_rate = dirtyrate;
>>  }
>>
>> +/*
>> + * get hash result for the sampled memory with length of TARGET_PAGE_SIZE
>> + * in ramblock, which starts from ramblock base address.
>> + */
>> +static uint32_t get_ramblock_vfn_hash(struct RamblockDirtyInfo *info,
>> +                                      uint64_t vfn)
>> +{
>> +    uint32_t crc;
>> +
>> +    crc = crc32(0, (info->ramblock_addr +
>> +                vfn * TARGET_PAGE_SIZE), TARGET_PAGE_SIZE);
>> +
>> +    return crc;
>> +}
>> +
>> +static bool save_ramblock_hash(struct RamblockDirtyInfo *info)
>> +{
>> +    unsigned int sample_pages_count;
>> +    int i;
>> +    GRand *rand;
>> +
>> +    sample_pages_count = info->sample_pages_count;
>> +
>> +    /* ramblock size less than one page, return success to skip this 
>> ramblock */
>> +    if (unlikely(info->ramblock_pages == 0 || sample_pages_count == 0)) {
>> +        return true;
>> +    }
>> +
>> +    info->hash_result = g_try_malloc0_n(sample_pages_count,
>> +                                        sizeof(uint32_t));
>> +    if (!info->hash_result) {
>> +        return false;
>> +    }
>> +
>> +    info->sample_page_vfn = g_try_malloc0_n(sample_pages_count,
>> +                                            sizeof(uint64_t));
>> +    if (!info->sample_page_vfn) {
>> +        g_free(info->hash_result);
>> +        return false;
>> +    }
>> +
>> +    rand  = g_rand_new();
>> +    for (i = 0; i < sample_pages_count; i++) {
>> +        info->sample_page_vfn[i] = g_rand_int_range(rand, 0,
>> +                                                    info->ramblock_pages - 
>> 1);
>> +        info->hash_result[i] = get_ramblock_vfn_hash(info,
>> +                                                     
>> info->sample_page_vfn[i]);
>> +    }
>> +    g_rand_free(rand);
>> +
>> +    return true;
>> +}
>> +
>> +static void get_ramblock_dirty_info(RAMBlock *block,
>> +                                    struct RamblockDirtyInfo *info,
>> +                                    struct DirtyRateConfig *config)
>> +{
>> +    uint64_t sample_pages_per_gigabytes = 
>> config->sample_pages_per_gigabytes;
>> +
>> +    /* Right shift 30 bits to calc ramblock size in GB */
>> +    info->sample_pages_count = (qemu_ram_get_used_length(block) *
>> +                                sample_pages_per_gigabytes) >> 30;
>> +    /* Right shift TARGET_PAGE_BITS to calc page count */
>> +    info->ramblock_pages = qemu_ram_get_used_length(block) >>
>> +                           TARGET_PAGE_BITS;
>> +    info->ramblock_addr = qemu_ram_get_host_addr(block);
>> +    strcpy(info->idstr, qemu_ram_get_idstr(block));
>> +}
>> +
>> +static bool record_ramblock_hash_info(struct RamblockDirtyInfo 
>> **block_dinfo,
>> +                                      struct DirtyRateConfig config,
>> +                                      int *block_index)
>> +{
>> +    struct RamblockDirtyInfo *info = NULL;
>> +    struct RamblockDirtyInfo *dinfo = NULL;
>> +    RAMBlock *block = NULL;
>> +    int total_index = 0;
> 
> Maybe 'total_count' better?
> 
>> +    int index = 0;
>> +    bool ret = true;
>> +
>> +    RAMBLOCK_FOREACH_MIGRATABLE(block) {
>> +        total_index++;
>> +    }
>> +
>> +    dinfo = g_try_malloc0_n(total_index, sizeof(struct RamblockDirtyInfo));
>> +    if (dinfo == NULL) {
>> +        total_index = 0;
> 
> No need to set 'total_index'.
> In the end use the 'index'.
> 
>> +        ret = false;
>> +        goto out;
>> +    }
>> +
>> +    RAMBLOCK_FOREACH_MIGRATABLE(block) {
>> +        if (index >= total_index) {
>> +            break;
>> +        }
>> +        info = &dinfo[index];
>> +        get_ramblock_dirty_info(block, info, &config);
>> +        if (!save_ramblock_hash(info)) {
>> +            ret = false;
>> +            goto out;
>> +        }
>> +        index++;
>> +    }
>> +
>> +out:
>> +    *block_index = total_index;
> 
> Here 'total_index' should be 'index'?
> 
Hi, Qiang.
Thanks for your review.
Yes, it should be index:), will fix in V9

> In general I think this two iteration version is more understandable
> that last one.
> 
> Thanks,
> Li Qiang
> 
>> +    *block_dinfo = dinfo;
>> +    return ret;
>> +}
>> +
>>  static void calculate_dirtyrate(struct DirtyRateConfig config)
>>  {
>>      /* todo */
>> --
>> 1.8.3.1
>>
> .
>