From: Zheng Chuan <zhengchuan@huawei.com>
Record hash results for each ramblock.
Signed-off-by: Zheng Chuan <zhengchuan@huawei.com>
Signed-off-by: YanYing Zhang <ann.zhuangyanying@huawei.com>
---
migration/dirtyrate.c | 157 ++++++++++++++++++++++++++++++++++++++++++++++++++
migration/dirtyrate.h | 1 +
2 files changed, 158 insertions(+)
diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c
index 6baf674..45cfc91 100644
--- a/migration/dirtyrate.c
+++ b/migration/dirtyrate.c
@@ -10,12 +10,27 @@
* See the COPYING file in the top-level directory.
*/
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "crypto/hash.h"
+#include "crypto/random.h"
+#include "qemu/config-file.h"
+#include "exec/memory.h"
+#include "exec/ramblock.h"
+#include "exec/target_page.h"
+#include "qemu/rcu_queue.h"
+#include "qapi/qapi-commands-migration.h"
+#include "migration.h"
#include "dirtyrate.h"
static uint64_t sample_pages_per_gigabytes = DIRTYRATE_DEFAULT_SAMPLE_PAGES;
static struct dirtyrate_statistics dirty_stat;
CalculatingDirtyRateStage calculating_dirty_rate_stage = CAL_DIRTY_RATE_INIT;
+#define RAMBLOCK_FOREACH_MIGRATABLE(block) \
+ INTERNAL_RAMBLOCK_FOREACH(block) \
+ if (!qemu_ram_is_migratable(block)) {} else
+
static void reset_dirtyrate_stat(void)
{
dirty_stat.total_dirty_samples = 0;
@@ -44,6 +59,148 @@ static void update_dirtyrate(int64_t msec)
dirty_stat.dirty_rate = dirty_rate;
}
+static int get_block_vfn_hash(struct block_dirty_info *info, unsigned long vfn,
+ uint8_t **md, size_t *hash_len)
+{
+ struct iovec iov_array;
+ int ret = 0;
+ int nkey = 1;
+
+ iov_array.iov_base = info->block_addr +
+ vfn * DIRTYRATE_SAMPLE_PAGE_SIZE;
+ iov_array.iov_len = DIRTYRATE_SAMPLE_PAGE_SIZE;
+
+ if (qcrypto_hash_bytesv(QCRYPTO_HASH_ALG_MD5,
+ &iov_array, nkey,
+ md, hash_len, NULL) < 0) {
+ ret = -1;
+ }
+
+ return ret;
+}
+
+static int save_block_hash(struct block_dirty_info *info)
+{
+ unsigned long *rand_buf = NULL;
+ unsigned int sample_pages_count;
+ uint8_t *md = NULL;
+ size_t hash_len;
+ int i;
+ int ret = -1;
+
+ sample_pages_count = info->sample_pages_count;
+ /* block size less than one page, return success to skip this block */
+ if (unlikely(info->block_pages == 0 || sample_pages_count == 0)) {
+ ret = 0;
+ goto out;
+ }
+
+ /* use random bytes to pick sample page vfn */
+ rand_buf = g_malloc0_n(sample_pages_count, sizeof(unsigned long));
+ /* DEFAULT_READ_RANDOM_MAX_LIMIT 32M,
+ * can support 4T vm 1024 sample_pages_per_gigabytes
+ */
+ ret = qcrypto_random_bytes((unsigned char *)rand_buf,
+ sample_pages_count * sizeof(unsigned long),
+ NULL);
+ if (ret) {
+ ret = -1;
+ goto out;
+ }
+
+ hash_len = qcrypto_hash_digest_len(QCRYPTO_HASH_ALG_MD5);
+ info->hash_result = g_malloc0_n(sample_pages_count, sizeof(uint8_t) * hash_len);
+ info->sample_page_vfn = g_malloc0_n(sample_pages_count, sizeof(unsigned long));
+
+ for (i = 0; i < sample_pages_count; i++) {
+ md = info->hash_result + i * hash_len;
+ info->sample_page_vfn[i] = rand_buf[i] % info->block_pages;
+ ret = get_block_vfn_hash(info, info->sample_page_vfn[i], &md, &hash_len);
+ if (ret < 0) {
+ goto out;
+ }
+ }
+ ret = 0;
+out:
+ g_free(rand_buf);
+ return ret;
+}
+
+static void get_block_dirty_info(RAMBlock *block, struct block_dirty_info *info,
+ struct dirtyrate_config *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) >> 30;
+
+ info->block_pages = qemu_ram_get_used_length(block) >> DIRTYRATE_PAGE_SIZE_SHIFT;
+ info->block_addr = qemu_ram_get_host_addr(block);
+ strcpy(info->idstr, qemu_ram_get_idstr(block));
+}
+
+static struct block_dirty_info *
+alloc_block_dirty_info(int *block_index,
+ struct block_dirty_info *block_dinfo)
+{
+ struct block_dirty_info *info = NULL;
+ int index = *block_index;
+
+ if (!block_dinfo) {
+ block_dinfo = g_new(struct block_dirty_info, 1);
+ index = 0;
+ } else {
+ block_dinfo = g_realloc(block_dinfo, (index + 1) *
+ sizeof(struct block_dirty_info));
+ index++;
+ }
+ info = &block_dinfo[index];
+ memset(info, 0, sizeof(struct block_dirty_info));
+
+ *block_index = index;
+ return block_dinfo;
+}
+
+static int ram_block_skip(RAMBlock *block)
+{
+ if (!strstr(qemu_ram_get_idstr(block), "ram-node") &&
+ !strstr(qemu_ram_get_idstr(block), "memdimm")) {
+ if (strcmp(qemu_ram_get_idstr(block), "mach-virt.ram") ||
+ strcmp(block->idstr, "pc.ram")) {
+ return -1;
+ }
+ }
+
+ return 0;
+}
+
+static int record_block_hash_info(struct dirtyrate_config config,
+ struct block_dirty_info **block_dinfo, int *block_index)
+{
+ struct block_dirty_info *info = NULL;
+ struct block_dirty_info *dinfo = NULL;
+ RAMBlock *block = NULL;
+ int index = 0;
+
+ RAMBLOCK_FOREACH_MIGRATABLE(block) {
+ if (ram_block_skip(block) < 0) {
+ continue;
+ }
+ dinfo = alloc_block_dirty_info(&index, dinfo);
+ info = &dinfo[index];
+ get_block_dirty_info(block, info, &config);
+ if (save_block_hash(info) < 0) {
+ *block_dinfo = dinfo;
+ *block_index = index;
+ return -1;
+ }
+ }
+
+ *block_dinfo = dinfo;
+ *block_index = index;
+
+ return 0;
+}
static void calculate_dirtyrate(struct dirtyrate_config config, int64_t time)
{
diff --git a/migration/dirtyrate.h b/migration/dirtyrate.h
index 2994535..4d9b3b8 100644
--- a/migration/dirtyrate.h
+++ b/migration/dirtyrate.h
@@ -15,6 +15,7 @@
/* take 256 pages per GB for cal dirty rate */
#define DIRTYRATE_DEFAULT_SAMPLE_PAGES 256
+#define DIRTYRATE_SAMPLE_PAGE_SIZE 4096
#define DIRTYRATE_PAGE_SIZE_SHIFT 12
#define BLOCK_INFO_MAX_LEN 256
#define PAGE_SIZE_SHIFT 20
--
1.8.3.1
* Chuan Zheng (zhengchuan@huawei.com) wrote:
> From: Zheng Chuan <zhengchuan@huawei.com>
>
> Record hash results for each ramblock.
Please be careful when talking about 'ramblock' since we already use
that for a chunk of memory in QEMU.
> Signed-off-by: Zheng Chuan <zhengchuan@huawei.com>
> Signed-off-by: YanYing Zhang <ann.zhuangyanying@huawei.com>
> ---
> migration/dirtyrate.c | 157 ++++++++++++++++++++++++++++++++++++++++++++++++++
> migration/dirtyrate.h | 1 +
> 2 files changed, 158 insertions(+)
>
> diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c
> index 6baf674..45cfc91 100644
> --- a/migration/dirtyrate.c
> +++ b/migration/dirtyrate.c
> @@ -10,12 +10,27 @@
> * See the COPYING file in the top-level directory.
> */
>
> +#include "qemu/osdep.h"
> +#include "qapi/error.h"
> +#include "crypto/hash.h"
> +#include "crypto/random.h"
> +#include "qemu/config-file.h"
> +#include "exec/memory.h"
> +#include "exec/ramblock.h"
> +#include "exec/target_page.h"
> +#include "qemu/rcu_queue.h"
> +#include "qapi/qapi-commands-migration.h"
> +#include "migration.h"
> #include "dirtyrate.h"
>
> static uint64_t sample_pages_per_gigabytes = DIRTYRATE_DEFAULT_SAMPLE_PAGES;
> static struct dirtyrate_statistics dirty_stat;
> CalculatingDirtyRateStage calculating_dirty_rate_stage = CAL_DIRTY_RATE_INIT;
>
> +#define RAMBLOCK_FOREACH_MIGRATABLE(block) \
> + INTERNAL_RAMBLOCK_FOREACH(block) \
> + if (!qemu_ram_is_migratable(block)) {} else
> +
Instead of redefining this here, please move the existing definition up
into migration/ram.h ?
> static void reset_dirtyrate_stat(void)
> {
> dirty_stat.total_dirty_samples = 0;
> @@ -44,6 +59,148 @@ static void update_dirtyrate(int64_t msec)
> dirty_stat.dirty_rate = dirty_rate;
> }
>
> +static int get_block_vfn_hash(struct block_dirty_info *info, unsigned long vfn,
> + uint8_t **md, size_t *hash_len)
> +{
> + struct iovec iov_array;
> + int ret = 0;
> + int nkey = 1;
> +
> + iov_array.iov_base = info->block_addr +
> + vfn * DIRTYRATE_SAMPLE_PAGE_SIZE;
> + iov_array.iov_len = DIRTYRATE_SAMPLE_PAGE_SIZE;
I'm a bit confused by how this is working; is 'vfn' an index
in SAMPLE_PAGE_SIZE's rather than individual pages? So this is
going to hash over something the size of a 'DIRTYRATE_SAMPLE_PAGE_SIZE'?
> + if (qcrypto_hash_bytesv(QCRYPTO_HASH_ALG_MD5,
> + &iov_array, nkey,
> + md, hash_len, NULL) < 0) {
> + ret = -1;
> + }
> +
> + return ret;
> +}
> +
> +static int save_block_hash(struct block_dirty_info *info)
> +{
> + unsigned long *rand_buf = NULL;
> + unsigned int sample_pages_count;
> + uint8_t *md = NULL;
> + size_t hash_len;
> + int i;
> + int ret = -1;
> +
> + sample_pages_count = info->sample_pages_count;
> + /* block size less than one page, return success to skip this block */
> + if (unlikely(info->block_pages == 0 || sample_pages_count == 0)) {
> + ret = 0;
> + goto out;
> + }
> +
> + /* use random bytes to pick sample page vfn */
> + rand_buf = g_malloc0_n(sample_pages_count, sizeof(unsigned long));
> + /* DEFAULT_READ_RANDOM_MAX_LIMIT 32M,
> + * can support 4T vm 1024 sample_pages_per_gigabytes
> + */
> + ret = qcrypto_random_bytes((unsigned char *)rand_buf,
> + sample_pages_count * sizeof(unsigned long),
> + NULL);
I think there may be a different way to do this without having to store
the rand_buf.
We already link to glib, and glib has a PRNG; https://developer.gnome.org/glib/stable/glib-Random-Numbers.html
If you create a new prng is g_rand_new() at the start of day, and take a
copy with g_rand_copy(), then you can replay the sequence of random
numbers it generates without actually storing the sequence.
So g_rand_new(), g_rand_copy() and then before you traverse the set of
pages you go and take a copy again and use the copy; it'll give the same
sequence every time.
Note also, because you're allocating a potentially large array,
for this and the hash_result please use g_try_malloc0_n (or g_try_new0)
and fail properly if it returns NULL.
Note we have users with more than 4T of RAM in their VMs, although I
doubt in a single RAMBlock
> + if (ret) {
> + ret = -1;
> + goto out;
> + }
> +
> + hash_len = qcrypto_hash_digest_len(QCRYPTO_HASH_ALG_MD5);
> + info->hash_result = g_malloc0_n(sample_pages_count, sizeof(uint8_t) * hash_len);
> + info->sample_page_vfn = g_malloc0_n(sample_pages_count, sizeof(unsigned long));
> +
> + for (i = 0; i < sample_pages_count; i++) {
> + md = info->hash_result + i * hash_len;
> + info->sample_page_vfn[i] = rand_buf[i] % info->block_pages;
> + ret = get_block_vfn_hash(info, info->sample_page_vfn[i], &md, &hash_len);
> + if (ret < 0) {
> + goto out;
> + }
> + }
> + ret = 0;
> +out:
> + g_free(rand_buf);
> + return ret;
> +}
> +
> +static void get_block_dirty_info(RAMBlock *block, struct block_dirty_info *info,
> + struct dirtyrate_config *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) >> 30;
> +
> + info->block_pages = qemu_ram_get_used_length(block) >> DIRTYRATE_PAGE_SIZE_SHIFT;
> + info->block_addr = qemu_ram_get_host_addr(block);
> + strcpy(info->idstr, qemu_ram_get_idstr(block));
> +}
> +
> +static struct block_dirty_info *
> +alloc_block_dirty_info(int *block_index,
> + struct block_dirty_info *block_dinfo)
> +{
> + struct block_dirty_info *info = NULL;
> + int index = *block_index;
> +
> + if (!block_dinfo) {
> + block_dinfo = g_new(struct block_dirty_info, 1);
> + index = 0;
> + } else {
> + block_dinfo = g_realloc(block_dinfo, (index + 1) *
> + sizeof(struct block_dirty_info));
> + index++;
I think g_realloc works on a NULL pointer, so you might be able to
simplify.
> + }
> + info = &block_dinfo[index];
> + memset(info, 0, sizeof(struct block_dirty_info));
> +
> + *block_index = index;
> + return block_dinfo;
> +}
> +
> +static int ram_block_skip(RAMBlock *block)
> +{
> + if (!strstr(qemu_ram_get_idstr(block), "ram-node") &&
> + !strstr(qemu_ram_get_idstr(block), "memdimm")) {
> + if (strcmp(qemu_ram_get_idstr(block), "mach-virt.ram") ||
> + strcmp(block->idstr, "pc.ram")) {
> + return -1;
> + }
> + }
We can't tie this to the names you guess that RAMBlocks might have -
things like 'memdimm' are settable by the caller and can be anything,
so you need to picka different way of chosing which RAMBlocks to
use; I suggest anything larger than some cutoff size, that's really RAM.
> + return 0;
> +}
> +
> +static int record_block_hash_info(struct dirtyrate_config config,
> + struct block_dirty_info **block_dinfo, int *block_index)
> +{
> + struct block_dirty_info *info = NULL;
> + struct block_dirty_info *dinfo = NULL;
> + RAMBlock *block = NULL;
> + int index = 0;
> +
> + RAMBLOCK_FOREACH_MIGRATABLE(block) {
> + if (ram_block_skip(block) < 0) {
> + continue;
> + }
> + dinfo = alloc_block_dirty_info(&index, dinfo);
> + info = &dinfo[index];
> + get_block_dirty_info(block, info, &config);
> + if (save_block_hash(info) < 0) {
> + *block_dinfo = dinfo;
> + *block_index = index;
> + return -1;
> + }
> + }
> +
> + *block_dinfo = dinfo;
> + *block_index = index;
> +
> + return 0;
> +}
>
> static void calculate_dirtyrate(struct dirtyrate_config config, int64_t time)
> {
> diff --git a/migration/dirtyrate.h b/migration/dirtyrate.h
> index 2994535..4d9b3b8 100644
> --- a/migration/dirtyrate.h
> +++ b/migration/dirtyrate.h
> @@ -15,6 +15,7 @@
>
> /* take 256 pages per GB for cal dirty rate */
> #define DIRTYRATE_DEFAULT_SAMPLE_PAGES 256
> +#define DIRTYRATE_SAMPLE_PAGE_SIZE 4096
> #define DIRTYRATE_PAGE_SIZE_SHIFT 12
> #define BLOCK_INFO_MAX_LEN 256
> #define PAGE_SIZE_SHIFT 20
> --
> 1.8.3.1
>
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
On 2020/8/5 1:00, Dr. David Alan Gilbert wrote:
> * Chuan Zheng (zhengchuan@huawei.com) wrote:
>> From: Zheng Chuan <zhengchuan@huawei.com>
>>
>> Record hash results for each ramblock.
>
> Please be careful when talking about 'ramblock' since we already use
> that for a chunk of memory in QEMU.
>
>> Signed-off-by: Zheng Chuan <zhengchuan@huawei.com>
>> Signed-off-by: YanYing Zhang <ann.zhuangyanying@huawei.com>
>> ---
>> migration/dirtyrate.c | 157 ++++++++++++++++++++++++++++++++++++++++++++++++++
>> migration/dirtyrate.h | 1 +
>> 2 files changed, 158 insertions(+)
>>
>> diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c
>> index 6baf674..45cfc91 100644
>> --- a/migration/dirtyrate.c
>> +++ b/migration/dirtyrate.c
>> @@ -10,12 +10,27 @@
>> * See the COPYING file in the top-level directory.
>> */
>>
>> +#include "qemu/osdep.h"
>> +#include "qapi/error.h"
>> +#include "crypto/hash.h"
>> +#include "crypto/random.h"
>> +#include "qemu/config-file.h"
>> +#include "exec/memory.h"
>> +#include "exec/ramblock.h"
>> +#include "exec/target_page.h"
>> +#include "qemu/rcu_queue.h"
>> +#include "qapi/qapi-commands-migration.h"
>> +#include "migration.h"
>> #include "dirtyrate.h"
>>
>> static uint64_t sample_pages_per_gigabytes = DIRTYRATE_DEFAULT_SAMPLE_PAGES;
>> static struct dirtyrate_statistics dirty_stat;
>> CalculatingDirtyRateStage calculating_dirty_rate_stage = CAL_DIRTY_RATE_INIT;
>>
>> +#define RAMBLOCK_FOREACH_MIGRATABLE(block) \
>> + INTERNAL_RAMBLOCK_FOREACH(block) \
>> + if (!qemu_ram_is_migratable(block)) {} else
>> +
>
> Instead of redefining this here, please move the existing definition up
> into migration/ram.h ?
>
OK, i'll do that in V2.
>> static void reset_dirtyrate_stat(void)
>> {
>> dirty_stat.total_dirty_samples = 0;
>> @@ -44,6 +59,148 @@ static void update_dirtyrate(int64_t msec)
>> dirty_stat.dirty_rate = dirty_rate;
>> }
>>
>> +static int get_block_vfn_hash(struct block_dirty_info *info, unsigned long vfn,
>> + uint8_t **md, size_t *hash_len)
>> +{
>> + struct iovec iov_array;
>> + int ret = 0;
>> + int nkey = 1;
>> +
>> + iov_array.iov_base = info->block_addr +
>> + vfn * DIRTYRATE_SAMPLE_PAGE_SIZE;
>> + iov_array.iov_len = DIRTYRATE_SAMPLE_PAGE_SIZE;
>
> I'm a bit confused by how this is working; is 'vfn' an index
> in SAMPLE_PAGE_SIZE's rather than individual pages? So this is
> going to hash over something the size of a 'DIRTYRATE_SAMPLE_PAGE_SIZE'?
>
Here is how sampling works for example.
1. assume block length is 1G, take 256 pages (sample_pages_count = 256) for sampling.
2. acquire rand_buf[256] and get 256 random pages over ramblock with "rand_buf[i] % info->block_pages;"
3. get hash results of 4K length for all 256 pages by qcrypto_hash_bytesv();
4. get hash results of 4K length for all 256 pages by qcrypto_hash_bytesv() again after sleep 1s;
5. compare hash results, and judge if it is the dirty during the sleep time;
6. calculate dirty rate.
Thus, vfn is an index, and we acquire hash result of the DIRTYRATE_SAMPLE_PAGE_SIZE length memory which starts from iov_base.
>> + if (qcrypto_hash_bytesv(QCRYPTO_HASH_ALG_MD5,
>> + &iov_array, nkey,
>> + md, hash_len, NULL) < 0) {
>> + ret = -1;
>> + }
>> +
>> + return ret;
>> +}
>> +
>> +static int save_block_hash(struct block_dirty_info *info)
>> +{
>> + unsigned long *rand_buf = NULL;
>> + unsigned int sample_pages_count;
>> + uint8_t *md = NULL;
>> + size_t hash_len;
>> + int i;
>> + int ret = -1;
>> +
>> + sample_pages_count = info->sample_pages_count;
>> + /* block size less than one page, return success to skip this block */
>> + if (unlikely(info->block_pages == 0 || sample_pages_count == 0)) {
>> + ret = 0;
>> + goto out;
>> + }
>> +
>> + /* use random bytes to pick sample page vfn */
>> + rand_buf = g_malloc0_n(sample_pages_count, sizeof(unsigned long));
>> + /* DEFAULT_READ_RANDOM_MAX_LIMIT 32M,
>> + * can support 4T vm 1024 sample_pages_per_gigabytes
>> + */
>> + ret = qcrypto_random_bytes((unsigned char *)rand_buf,
>> + sample_pages_count * sizeof(unsigned long),
>> + NULL);
>
> I think there may be a different way to do this without having to store
> the rand_buf.
> We already link to glib, and glib has a PRNG; https://developer.gnome.org/glib/stable/glib-Random-Numbers.html
> If you create a new prng is g_rand_new() at the start of day, and take a
> copy with g_rand_copy(), then you can replay the sequence of random
> numbers it generates without actually storing the sequence.
> So g_rand_new(), g_rand_copy() and then before you traverse the set of
> pages you go and take a copy again and use the copy; it'll give the same
> sequence every time.
>
> Note also, because you're allocating a potentially large array,
> for this and the hash_result please use g_try_malloc0_n (or g_try_new0)
> and fail properly if it returns NULL.
>
Sure, i'll consider that in V2.
> Note we have users with more than 4T of RAM in their VMs, although I
> doubt in a single RAMBlock
>
>> + if (ret) {
>> + ret = -1;
>> + goto out;
>> + }
>> +
>> + hash_len = qcrypto_hash_digest_len(QCRYPTO_HASH_ALG_MD5);
>> + info->hash_result = g_malloc0_n(sample_pages_count, sizeof(uint8_t) * hash_len);
>> + info->sample_page_vfn = g_malloc0_n(sample_pages_count, sizeof(unsigned long));
>> +
>> + for (i = 0; i < sample_pages_count; i++) {
>> + md = info->hash_result + i * hash_len;
>> + info->sample_page_vfn[i] = rand_buf[i] % info->block_pages;
>> + ret = get_block_vfn_hash(info, info->sample_page_vfn[i], &md, &hash_len);
>> + if (ret < 0) {
>> + goto out;
>> + }
>> + }
>> + ret = 0;
>> +out:
>> + g_free(rand_buf);
>> + return ret;
>> +}
>> +
>> +static void get_block_dirty_info(RAMBlock *block, struct block_dirty_info *info,
>> + struct dirtyrate_config *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) >> 30;
>> +
>> + info->block_pages = qemu_ram_get_used_length(block) >> DIRTYRATE_PAGE_SIZE_SHIFT;
>> + info->block_addr = qemu_ram_get_host_addr(block);
>> + strcpy(info->idstr, qemu_ram_get_idstr(block));
>> +}
>> +
>> +static struct block_dirty_info *
>> +alloc_block_dirty_info(int *block_index,
>> + struct block_dirty_info *block_dinfo)
>> +{
>> + struct block_dirty_info *info = NULL;
>> + int index = *block_index;
>> +
>> + if (!block_dinfo) {
>> + block_dinfo = g_new(struct block_dirty_info, 1);
>> + index = 0;
>> + } else {
>> + block_dinfo = g_realloc(block_dinfo, (index + 1) *
>> + sizeof(struct block_dirty_info));
>> + index++;
>
> I think g_realloc works on a NULL pointer, so you might be able to
> simplify.
>
>> + }
>> + info = &block_dinfo[index];
>> + memset(info, 0, sizeof(struct block_dirty_info));
>> +
>> + *block_index = index;
>> + return block_dinfo;
>> +}
>> +
>> +static int ram_block_skip(RAMBlock *block)
>> +{
>> + if (!strstr(qemu_ram_get_idstr(block), "ram-node") &&
>> + !strstr(qemu_ram_get_idstr(block), "memdimm")) {
>> + if (strcmp(qemu_ram_get_idstr(block), "mach-virt.ram") ||
>> + strcmp(block->idstr, "pc.ram")) {
>> + return -1;
>> + }
>> + }
>
> We can't tie this to the names you guess that RAMBlocks might have -
> things like 'memdimm' are settable by the caller and can be anything,
> so you need to picka different way of chosing which RAMBlocks to
> use; I suggest anything larger than some cutoff size, that's really RAM.
>
OK, i'll consider it in a general way.
>> + return 0;
>> +}
>> +
>> +static int record_block_hash_info(struct dirtyrate_config config,
>> + struct block_dirty_info **block_dinfo, int *block_index)
>> +{
>> + struct block_dirty_info *info = NULL;
>> + struct block_dirty_info *dinfo = NULL;
>> + RAMBlock *block = NULL;
>> + int index = 0;
>> +
>> + RAMBLOCK_FOREACH_MIGRATABLE(block) {
>> + if (ram_block_skip(block) < 0) {
>> + continue;
>> + }
>> + dinfo = alloc_block_dirty_info(&index, dinfo);
>> + info = &dinfo[index];
>> + get_block_dirty_info(block, info, &config);
>> + if (save_block_hash(info) < 0) {
>> + *block_dinfo = dinfo;
>> + *block_index = index;
>> + return -1;
>> + }
>> + }
>> +
>> + *block_dinfo = dinfo;
>> + *block_index = index;
>> +
>> + return 0;
>> +}
>>
>> static void calculate_dirtyrate(struct dirtyrate_config config, int64_t time)
>> {
>> diff --git a/migration/dirtyrate.h b/migration/dirtyrate.h
>> index 2994535..4d9b3b8 100644
>> --- a/migration/dirtyrate.h
>> +++ b/migration/dirtyrate.h
>> @@ -15,6 +15,7 @@
>>
>> /* take 256 pages per GB for cal dirty rate */
>> #define DIRTYRATE_DEFAULT_SAMPLE_PAGES 256
>> +#define DIRTYRATE_SAMPLE_PAGE_SIZE 4096
>> #define DIRTYRATE_PAGE_SIZE_SHIFT 12
>> #define BLOCK_INFO_MAX_LEN 256
>> #define PAGE_SIZE_SHIFT 20
>> --
>> 1.8.3.1
>>
> --
> Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
>
>
> .
>
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