diff mbox series

[v5,06/12] migration/dirtyrate: Record hash results for each sampled page

Message ID 1598319650-36762-7-git-send-email-zhengchuan@huawei.com (mailing list archive)
State New, archived
Headers show
Series *** A Method for evaluating dirty page rate *** | expand

Commit Message

Zheng Chuan Aug. 25, 2020, 1:40 a.m. UTC 
Record hash results for each sampled page, crc32 is taken to calculate
hash results for each sampled 4K-page.

Signed-off-by: Chuan Zheng <zhengchuan@huawei.com>
Signed-off-by: YanYing Zhuang <ann.zhuangyanying@huawei.com>
---
 migration/dirtyrate.c | 136 ++++++++++++++++++++++++++++++++++++++++++++++++++
 migration/dirtyrate.h |  15 ++++++
 2 files changed, 151 insertions(+)

Comments

Dr. David Alan Gilbert Aug. 26, 2020, 12:35 p.m. UTC | #1 
* Chuan Zheng (zhengchuan@huawei.com) wrote:
> Record hash results for each sampled page, crc32 is taken to calculate
> hash results for each sampled 4K-page.
> 
> Signed-off-by: Chuan Zheng <zhengchuan@huawei.com>
> Signed-off-by: YanYing Zhuang <ann.zhuangyanying@huawei.com>
> ---
>  migration/dirtyrate.c | 136 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  migration/dirtyrate.h |  15 ++++++
>  2 files changed, 151 insertions(+)
> 
> diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c
> index f6a94d8..66de426 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 "crypto/hash.h"
> @@ -66,6 +67,141 @@ static void update_dirtyrate(uint64_t msec)
>      DirtyStat.dirty_rate = dirtyrate;
>  }
>  
> +/*
> + * get hash result for the sampled memory with length of 4K byte in ramblock,
> + * which starts from ramblock base address.
> + */
> +static uint32_t get_ramblock_vfn_hash(struct RamblockDirtyInfo *info,
> +                                      uint64_t vfn)
> +{
> +    struct iovec iov_array;
> +    uint32_t crc;
> +
> +    iov_array.iov_base = info->ramblock_addr +
> +                         vfn * DIRTYRATE_SAMPLE_PAGE_SIZE;
> +    iov_array.iov_len = DIRTYRATE_SAMPLE_PAGE_SIZE;
> +
> +    crc = crc32(0, iov_array.iov_base, iov_array.iov_len);
> +
> +    return crc;
> +}
> +
> +static int save_ramblock_hash(struct RamblockDirtyInfo *info)
> +{
> +    unsigned int sample_pages_count;
> +    int i;
> +    int ret = -1;
> +    GRand *rand = g_rand_new();
> +
> +    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)) {
> +        ret = 0;
> +        goto out;
> +    }
> +
> +    info->hash_result = g_try_malloc0_n(sample_pages_count,
> +                                        sizeof(uint32_t));
> +    if (!info->hash_result) {
> +        ret = -1;
> +        goto out;
> +    }
> +
> +    info->sample_page_vfn = g_try_malloc0_n(sample_pages_count,
> +                                            sizeof(uint64_t));
> +    if (!info->sample_page_vfn) {
> +        g_free(info->hash_result);
> +        ret = -1;
> +        goto out;
> +    }
> +
> +    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]);
> +    }
> +    ret = 0;
> +
> +out:
> +    g_rand_free(rand);
> +    return ret;
> +}
> +
> +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 block size in GB */
> +    info->sample_pages_count = (qemu_ram_get_used_length(block) *
> +                                sample_pages_per_gigabytes) >>
> +                                DIRTYRATE_PAGE_SHIFT_GB;
> +
> +    /* Right shift 12 bits to calc page count in 4KB */
> +    info->ramblock_pages = qemu_ram_get_used_length(block) >>
> +                           DIRTYRATE_PAGE_SHIFT_KB;
> +    info->ramblock_addr = qemu_ram_get_host_addr(block);
> +    strcpy(info->idstr, qemu_ram_get_idstr(block));
> +}
> +
> +static struct RamblockDirtyInfo *
> +alloc_ramblock_dirty_info(int *block_index,
> +                          struct RamblockDirtyInfo *block_dinfo)
> +{
> +    struct RamblockDirtyInfo *info = NULL;
> +    int index = *block_index;
> +
> +    if (!block_dinfo) {
> +        index = 0;
> +        block_dinfo = g_try_new(struct RamblockDirtyInfo, 1);
> +    } else {
> +        index++;
> +        block_dinfo = g_try_realloc(block_dinfo, (index + 1) *
> +                                    sizeof(struct RamblockDirtyInfo));
> +    }
> +    if (!block_dinfo) {
> +        return NULL;
> +    }
> +
> +    info = &block_dinfo[index];
> +    *block_index = index;
> +    memset(info, 0, sizeof(struct RamblockDirtyInfo));
> +
> +    return block_dinfo;
> +}
> +
> +static int 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 index = 0;
> +
> +    RAMBLOCK_FOREACH_MIGRATABLE(block) {
> +        dinfo = alloc_ramblock_dirty_info(&index, dinfo);
> +        if (dinfo == NULL) {
> +            return -1;
> +        }
> +        info = &dinfo[index];
> +        get_ramblock_dirty_info(block, info, &config);
> +        if (save_ramblock_hash(info) < 0) {
> +            *block_dinfo = dinfo;
> +            *block_index = index;
> +            return -1;
> +        }
> +    }
> +
> +    *block_dinfo = dinfo;
> +    *block_index = index;
> +
> +    return 0;
> +}
> +
>  static void calculate_dirtyrate(struct DirtyRateConfig config)
>  {
>      /* todo */
> diff --git a/migration/dirtyrate.h b/migration/dirtyrate.h
> index 8e25d93..e3adead 100644
> --- a/migration/dirtyrate.h
> +++ b/migration/dirtyrate.h
> @@ -24,6 +24,21 @@
>   */
>  #define RAMBLOCK_INFO_MAX_LEN                     256
>  
> +/*
> + * Sample page size 4K as default.
> + */
> +#define DIRTYRATE_SAMPLE_PAGE_SIZE                4096
> +
> +/*
> + * Sample page size 4K shift
> + */
> +#define DIRTYRATE_PAGE_SHIFT_KB                   12
> +
> +/*
> + * Sample page size 1G shift
> + */
> +#define DIRTYRATE_PAGE_SHIFT_GB                   30

Your naming is really odd here;  'PAGE_SHIFT_KB' divides
by 4KB, where as 'PAGE_SHIFT_GB' divices by 1KB.

Simplify this;  you can just do >>30 for GB because it's well known;
you don't need a #define constant for simple KB,MB,GB since
we all know them.

Also, I've asked before - do you really want 4KB explicitly - or
should you just use TARGET_PAGE_SIZE and TARGET_PAGE_BITS ?

Dave

> +
>  /* Take 1s as default for calculation duration */
>  #define DEFAULT_FETCH_DIRTYRATE_TIME_SEC          1
>  
> -- 
> 1.8.3.1
>
Zheng Chuan Aug. 27, 2020, 6:41 a.m. UTC | #2 
On 2020/8/26 20:35, Dr. David Alan Gilbert wrote:
> * Chuan Zheng (zhengchuan@huawei.com) wrote:
>> Record hash results for each sampled page, crc32 is taken to calculate
>> hash results for each sampled 4K-page.
>>
>> Signed-off-by: Chuan Zheng <zhengchuan@huawei.com>
>> Signed-off-by: YanYing Zhuang <ann.zhuangyanying@huawei.com>
>> ---
>>  migration/dirtyrate.c | 136 ++++++++++++++++++++++++++++++++++++++++++++++++++
>>  migration/dirtyrate.h |  15 ++++++
>>  2 files changed, 151 insertions(+)
>>
>> diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c
>> index f6a94d8..66de426 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 "crypto/hash.h"
>> @@ -66,6 +67,141 @@ static void update_dirtyrate(uint64_t msec)
>>      DirtyStat.dirty_rate = dirtyrate;
>>  }
>>  
>> +/*
>> + * get hash result for the sampled memory with length of 4K byte in ramblock,
>> + * which starts from ramblock base address.
>> + */
>> +static uint32_t get_ramblock_vfn_hash(struct RamblockDirtyInfo *info,
>> +                                      uint64_t vfn)
>> +{
>> +    struct iovec iov_array;
>> +    uint32_t crc;
>> +
>> +    iov_array.iov_base = info->ramblock_addr +
>> +                         vfn * DIRTYRATE_SAMPLE_PAGE_SIZE;
>> +    iov_array.iov_len = DIRTYRATE_SAMPLE_PAGE_SIZE;
>> +
>> +    crc = crc32(0, iov_array.iov_base, iov_array.iov_len);
>> +
>> +    return crc;
>> +}
>> +
>> +static int save_ramblock_hash(struct RamblockDirtyInfo *info)
>> +{
>> +    unsigned int sample_pages_count;
>> +    int i;
>> +    int ret = -1;
>> +    GRand *rand = g_rand_new();
>> +
>> +    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)) {
>> +        ret = 0;
>> +        goto out;
>> +    }
>> +
>> +    info->hash_result = g_try_malloc0_n(sample_pages_count,
>> +                                        sizeof(uint32_t));
>> +    if (!info->hash_result) {
>> +        ret = -1;
>> +        goto out;
>> +    }
>> +
>> +    info->sample_page_vfn = g_try_malloc0_n(sample_pages_count,
>> +                                            sizeof(uint64_t));
>> +    if (!info->sample_page_vfn) {
>> +        g_free(info->hash_result);
>> +        ret = -1;
>> +        goto out;
>> +    }
>> +
>> +    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]);
>> +    }
>> +    ret = 0;
>> +
>> +out:
>> +    g_rand_free(rand);
>> +    return ret;
>> +}
>> +
>> +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 block size in GB */
>> +    info->sample_pages_count = (qemu_ram_get_used_length(block) *
>> +                                sample_pages_per_gigabytes) >>
>> +                                DIRTYRATE_PAGE_SHIFT_GB;
>> +
>> +    /* Right shift 12 bits to calc page count in 4KB */
>> +    info->ramblock_pages = qemu_ram_get_used_length(block) >>
>> +                           DIRTYRATE_PAGE_SHIFT_KB;
>> +    info->ramblock_addr = qemu_ram_get_host_addr(block);
>> +    strcpy(info->idstr, qemu_ram_get_idstr(block));
>> +}
>> +
>> +static struct RamblockDirtyInfo *
>> +alloc_ramblock_dirty_info(int *block_index,
>> +                          struct RamblockDirtyInfo *block_dinfo)
>> +{
>> +    struct RamblockDirtyInfo *info = NULL;
>> +    int index = *block_index;
>> +
>> +    if (!block_dinfo) {
>> +        index = 0;
>> +        block_dinfo = g_try_new(struct RamblockDirtyInfo, 1);
>> +    } else {
>> +        index++;
>> +        block_dinfo = g_try_realloc(block_dinfo, (index + 1) *
>> +                                    sizeof(struct RamblockDirtyInfo));
>> +    }
>> +    if (!block_dinfo) {
>> +        return NULL;
>> +    }
>> +
>> +    info = &block_dinfo[index];
>> +    *block_index = index;
>> +    memset(info, 0, sizeof(struct RamblockDirtyInfo));
>> +
>> +    return block_dinfo;
>> +}
>> +
>> +static int 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 index = 0;
>> +
>> +    RAMBLOCK_FOREACH_MIGRATABLE(block) {
>> +        dinfo = alloc_ramblock_dirty_info(&index, dinfo);
>> +        if (dinfo == NULL) {
>> +            return -1;
>> +        }
>> +        info = &dinfo[index];
>> +        get_ramblock_dirty_info(block, info, &config);
>> +        if (save_ramblock_hash(info) < 0) {
>> +            *block_dinfo = dinfo;
>> +            *block_index = index;
>> +            return -1;
>> +        }
>> +    }
>> +
>> +    *block_dinfo = dinfo;
>> +    *block_index = index;
>> +
>> +    return 0;
>> +}
>> +
>>  static void calculate_dirtyrate(struct DirtyRateConfig config)
>>  {
>>      /* todo */
>> diff --git a/migration/dirtyrate.h b/migration/dirtyrate.h
>> index 8e25d93..e3adead 100644
>> --- a/migration/dirtyrate.h
>> +++ b/migration/dirtyrate.h
>> @@ -24,6 +24,21 @@
>>   */
>>  #define RAMBLOCK_INFO_MAX_LEN                     256
>>  
>> +/*
>> + * Sample page size 4K as default.
>> + */
>> +#define DIRTYRATE_SAMPLE_PAGE_SIZE                4096
>> +
>> +/*
>> + * Sample page size 4K shift
>> + */
>> +#define DIRTYRATE_PAGE_SHIFT_KB                   12
>> +
>> +/*
>> + * Sample page size 1G shift
>> + */
>> +#define DIRTYRATE_PAGE_SHIFT_GB                   30
> 
> Your naming is really odd here;  'PAGE_SHIFT_KB' divides
> by 4KB, where as 'PAGE_SHIFT_GB' divices by 1KB.
> 
> Simplify this;  you can just do >>30 for GB because it's well known;
> you don't need a #define constant for simple KB,MB,GB since
> we all know them.
> 
Hi, Dave.
Thank you for review.
OK, i will fix that in V6:)
> Also, I've asked before - do you really want 4KB explicitly - or
> should you just use TARGET_PAGE_SIZE and TARGET_PAGE_BITS ?
> 
> Dave
>
TARGET_PAGE_SIZE will be 2M or 1G for HugePage.
As you see, what we get is hash result of every 'virtual' 4K-page.
We care about if it is dirty within 4K length in ramblock, which would be more
accurate than TARGET_PAGE_SIZE which could be 2M or 1G.
On the other hand, the hugepage will be broken up into 4K during migration.

I think it is better we do hash at 'virtual' 4K-page granularity.

>> +
>>  /* Take 1s as default for calculation duration */
>>  #define DEFAULT_FETCH_DIRTYRATE_TIME_SEC          1
>>  
>> -- 
>> 1.8.3.1
>>
Dr. David Alan Gilbert Aug. 27, 2020, 8:31 a.m. UTC | #3 
* Zheng Chuan (zhengchuan@huawei.com) wrote:
> 
> 
> On 2020/8/26 20:35, Dr. David Alan Gilbert wrote:
> > * Chuan Zheng (zhengchuan@huawei.com) wrote:
> >> Record hash results for each sampled page, crc32 is taken to calculate
> >> hash results for each sampled 4K-page.
> >>
> >> Signed-off-by: Chuan Zheng <zhengchuan@huawei.com>
> >> Signed-off-by: YanYing Zhuang <ann.zhuangyanying@huawei.com>
> >> ---
> >>  migration/dirtyrate.c | 136 ++++++++++++++++++++++++++++++++++++++++++++++++++
> >>  migration/dirtyrate.h |  15 ++++++
> >>  2 files changed, 151 insertions(+)
> >>
> >> diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c
> >> index f6a94d8..66de426 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 "crypto/hash.h"
> >> @@ -66,6 +67,141 @@ static void update_dirtyrate(uint64_t msec)
> >>      DirtyStat.dirty_rate = dirtyrate;
> >>  }
> >>  
> >> +/*
> >> + * get hash result for the sampled memory with length of 4K byte in ramblock,
> >> + * which starts from ramblock base address.
> >> + */
> >> +static uint32_t get_ramblock_vfn_hash(struct RamblockDirtyInfo *info,
> >> +                                      uint64_t vfn)
> >> +{
> >> +    struct iovec iov_array;
> >> +    uint32_t crc;
> >> +
> >> +    iov_array.iov_base = info->ramblock_addr +
> >> +                         vfn * DIRTYRATE_SAMPLE_PAGE_SIZE;
> >> +    iov_array.iov_len = DIRTYRATE_SAMPLE_PAGE_SIZE;
> >> +
> >> +    crc = crc32(0, iov_array.iov_base, iov_array.iov_len);
> >> +
> >> +    return crc;
> >> +}
> >> +
> >> +static int save_ramblock_hash(struct RamblockDirtyInfo *info)
> >> +{
> >> +    unsigned int sample_pages_count;
> >> +    int i;
> >> +    int ret = -1;
> >> +    GRand *rand = g_rand_new();
> >> +
> >> +    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)) {
> >> +        ret = 0;
> >> +        goto out;
> >> +    }
> >> +
> >> +    info->hash_result = g_try_malloc0_n(sample_pages_count,
> >> +                                        sizeof(uint32_t));
> >> +    if (!info->hash_result) {
> >> +        ret = -1;
> >> +        goto out;
> >> +    }
> >> +
> >> +    info->sample_page_vfn = g_try_malloc0_n(sample_pages_count,
> >> +                                            sizeof(uint64_t));
> >> +    if (!info->sample_page_vfn) {
> >> +        g_free(info->hash_result);
> >> +        ret = -1;
> >> +        goto out;
> >> +    }
> >> +
> >> +    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]);
> >> +    }
> >> +    ret = 0;
> >> +
> >> +out:
> >> +    g_rand_free(rand);
> >> +    return ret;
> >> +}
> >> +
> >> +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 block size in GB */
> >> +    info->sample_pages_count = (qemu_ram_get_used_length(block) *
> >> +                                sample_pages_per_gigabytes) >>
> >> +                                DIRTYRATE_PAGE_SHIFT_GB;
> >> +
> >> +    /* Right shift 12 bits to calc page count in 4KB */
> >> +    info->ramblock_pages = qemu_ram_get_used_length(block) >>
> >> +                           DIRTYRATE_PAGE_SHIFT_KB;
> >> +    info->ramblock_addr = qemu_ram_get_host_addr(block);
> >> +    strcpy(info->idstr, qemu_ram_get_idstr(block));
> >> +}
> >> +
> >> +static struct RamblockDirtyInfo *
> >> +alloc_ramblock_dirty_info(int *block_index,
> >> +                          struct RamblockDirtyInfo *block_dinfo)
> >> +{
> >> +    struct RamblockDirtyInfo *info = NULL;
> >> +    int index = *block_index;
> >> +
> >> +    if (!block_dinfo) {
> >> +        index = 0;
> >> +        block_dinfo = g_try_new(struct RamblockDirtyInfo, 1);
> >> +    } else {
> >> +        index++;
> >> +        block_dinfo = g_try_realloc(block_dinfo, (index + 1) *
> >> +                                    sizeof(struct RamblockDirtyInfo));
> >> +    }
> >> +    if (!block_dinfo) {
> >> +        return NULL;
> >> +    }
> >> +
> >> +    info = &block_dinfo[index];
> >> +    *block_index = index;
> >> +    memset(info, 0, sizeof(struct RamblockDirtyInfo));
> >> +
> >> +    return block_dinfo;
> >> +}
> >> +
> >> +static int 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 index = 0;
> >> +
> >> +    RAMBLOCK_FOREACH_MIGRATABLE(block) {
> >> +        dinfo = alloc_ramblock_dirty_info(&index, dinfo);
> >> +        if (dinfo == NULL) {
> >> +            return -1;
> >> +        }
> >> +        info = &dinfo[index];
> >> +        get_ramblock_dirty_info(block, info, &config);
> >> +        if (save_ramblock_hash(info) < 0) {
> >> +            *block_dinfo = dinfo;
> >> +            *block_index = index;
> >> +            return -1;
> >> +        }
> >> +    }
> >> +
> >> +    *block_dinfo = dinfo;
> >> +    *block_index = index;
> >> +
> >> +    return 0;
> >> +}
> >> +
> >>  static void calculate_dirtyrate(struct DirtyRateConfig config)
> >>  {
> >>      /* todo */
> >> diff --git a/migration/dirtyrate.h b/migration/dirtyrate.h
> >> index 8e25d93..e3adead 100644
> >> --- a/migration/dirtyrate.h
> >> +++ b/migration/dirtyrate.h
> >> @@ -24,6 +24,21 @@
> >>   */
> >>  #define RAMBLOCK_INFO_MAX_LEN                     256
> >>  
> >> +/*
> >> + * Sample page size 4K as default.
> >> + */
> >> +#define DIRTYRATE_SAMPLE_PAGE_SIZE                4096
> >> +
> >> +/*
> >> + * Sample page size 4K shift
> >> + */
> >> +#define DIRTYRATE_PAGE_SHIFT_KB                   12
> >> +
> >> +/*
> >> + * Sample page size 1G shift
> >> + */
> >> +#define DIRTYRATE_PAGE_SHIFT_GB                   30
> > 
> > Your naming is really odd here;  'PAGE_SHIFT_KB' divides
> > by 4KB, where as 'PAGE_SHIFT_GB' divices by 1KB.
> > 
> > Simplify this;  you can just do >>30 for GB because it's well known;
> > you don't need a #define constant for simple KB,MB,GB since
> > we all know them.
> > 
> Hi, Dave.
> Thank you for review.
> OK, i will fix that in V6:)
> > Also, I've asked before - do you really want 4KB explicitly - or
> > should you just use TARGET_PAGE_SIZE and TARGET_PAGE_BITS ?
> > 
> > Dave
> >
> TARGET_PAGE_SIZE will be 2M or 1G for HugePage.
> As you see, what we get is hash result of every 'virtual' 4K-page.
> We care about if it is dirty within 4K length in ramblock, which would be more
> accurate than TARGET_PAGE_SIZE which could be 2M or 1G.
> On the other hand, the hugepage will be broken up into 4K during migration.
> 
> I think it is better we do hash at 'virtual' 4K-page granularity.

TARGET_PAGE_SIZE is never 2M or 1G; it's always based on the smallest
MMU page on the platform; on x86 it's always 4kB; it's the unit that the
migration code works in when dealing with pages.
(use TARGET_PAGE_BITS to shift by).

Dave

> >> +
> >>  /* Take 1s as default for calculation duration */
> >>  #define DEFAULT_FETCH_DIRTYRATE_TIME_SEC          1
> >>  
> >> -- 
> >> 1.8.3.1
> >>
>
diff mbox series

Patch

diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c
index f6a94d8..66de426 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 "crypto/hash.h"
@@ -66,6 +67,141 @@  static void update_dirtyrate(uint64_t msec)
     DirtyStat.dirty_rate = dirtyrate;
 }
 
+/*
+ * get hash result for the sampled memory with length of 4K byte in ramblock,
+ * which starts from ramblock base address.
+ */
+static uint32_t get_ramblock_vfn_hash(struct RamblockDirtyInfo *info,
+                                      uint64_t vfn)
+{
+    struct iovec iov_array;
+    uint32_t crc;
+
+    iov_array.iov_base = info->ramblock_addr +
+                         vfn * DIRTYRATE_SAMPLE_PAGE_SIZE;
+    iov_array.iov_len = DIRTYRATE_SAMPLE_PAGE_SIZE;
+
+    crc = crc32(0, iov_array.iov_base, iov_array.iov_len);
+
+    return crc;
+}
+
+static int save_ramblock_hash(struct RamblockDirtyInfo *info)
+{
+    unsigned int sample_pages_count;
+    int i;
+    int ret = -1;
+    GRand *rand = g_rand_new();
+
+    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)) {
+        ret = 0;
+        goto out;
+    }
+
+    info->hash_result = g_try_malloc0_n(sample_pages_count,
+                                        sizeof(uint32_t));
+    if (!info->hash_result) {
+        ret = -1;
+        goto out;
+    }
+
+    info->sample_page_vfn = g_try_malloc0_n(sample_pages_count,
+                                            sizeof(uint64_t));
+    if (!info->sample_page_vfn) {
+        g_free(info->hash_result);
+        ret = -1;
+        goto out;
+    }
+
+    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]);
+    }
+    ret = 0;
+
+out:
+    g_rand_free(rand);
+    return ret;
+}
+
+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 block size in GB */
+    info->sample_pages_count = (qemu_ram_get_used_length(block) *
+                                sample_pages_per_gigabytes) >>
+                                DIRTYRATE_PAGE_SHIFT_GB;
+
+    /* Right shift 12 bits to calc page count in 4KB */
+    info->ramblock_pages = qemu_ram_get_used_length(block) >>
+                           DIRTYRATE_PAGE_SHIFT_KB;
+    info->ramblock_addr = qemu_ram_get_host_addr(block);
+    strcpy(info->idstr, qemu_ram_get_idstr(block));
+}
+
+static struct RamblockDirtyInfo *
+alloc_ramblock_dirty_info(int *block_index,
+                          struct RamblockDirtyInfo *block_dinfo)
+{
+    struct RamblockDirtyInfo *info = NULL;
+    int index = *block_index;
+
+    if (!block_dinfo) {
+        index = 0;
+        block_dinfo = g_try_new(struct RamblockDirtyInfo, 1);
+    } else {
+        index++;
+        block_dinfo = g_try_realloc(block_dinfo, (index + 1) *
+                                    sizeof(struct RamblockDirtyInfo));
+    }
+    if (!block_dinfo) {
+        return NULL;
+    }
+
+    info = &block_dinfo[index];
+    *block_index = index;
+    memset(info, 0, sizeof(struct RamblockDirtyInfo));
+
+    return block_dinfo;
+}
+
+static int 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 index = 0;
+
+    RAMBLOCK_FOREACH_MIGRATABLE(block) {
+        dinfo = alloc_ramblock_dirty_info(&index, dinfo);
+        if (dinfo == NULL) {
+            return -1;
+        }
+        info = &dinfo[index];
+        get_ramblock_dirty_info(block, info, &config);
+        if (save_ramblock_hash(info) < 0) {
+            *block_dinfo = dinfo;
+            *block_index = index;
+            return -1;
+        }
+    }
+
+    *block_dinfo = dinfo;
+    *block_index = index;
+
+    return 0;
+}
+
 static void calculate_dirtyrate(struct DirtyRateConfig config)
 {
     /* todo */
diff --git a/migration/dirtyrate.h b/migration/dirtyrate.h
index 8e25d93..e3adead 100644
--- a/migration/dirtyrate.h
+++ b/migration/dirtyrate.h
@@ -24,6 +24,21 @@ 
  */
 #define RAMBLOCK_INFO_MAX_LEN                     256
 
+/*
+ * Sample page size 4K as default.
+ */
+#define DIRTYRATE_SAMPLE_PAGE_SIZE                4096
+
+/*
+ * Sample page size 4K shift
+ */
+#define DIRTYRATE_PAGE_SHIFT_KB                   12
+
+/*
+ * Sample page size 1G shift
+ */
+#define DIRTYRATE_PAGE_SHIFT_GB                   30
+
 /* Take 1s as default for calculation duration */
 #define DEFAULT_FETCH_DIRTYRATE_TIME_SEC          1