qemu/migration/dirtyrate.c

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/*
* Dirtyrate implement code
*
* Copyright (c) 2020 HUAWEI TECHNOLOGIES CO.,LTD.
*
* Authors:
* Chuan Zheng <zhengchuan@huawei.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include <zlib.h>
#include "qapi/error.h"
#include "cpu.h"
#include "exec/ramblock.h"
#include "qemu/rcu_queue.h"
#include "qapi/qapi-commands-migration.h"
#include "ram.h"
#include "trace.h"
#include "dirtyrate.h"
#include "monitor/hmp.h"
#include "monitor/monitor.h"
#include "qapi/qmp/qdict.h"
static int CalculatingState = DIRTY_RATE_STATUS_UNSTARTED;
static struct DirtyRateStat DirtyStat;
static int64_t set_sample_page_period(int64_t msec, int64_t initial_time)
{
int64_t current_time;
current_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
if ((current_time - initial_time) >= msec) {
msec = current_time - initial_time;
} else {
g_usleep((msec + initial_time - current_time) * 1000);
}
return msec;
}
static bool is_sample_period_valid(int64_t sec)
{
if (sec < MIN_FETCH_DIRTYRATE_TIME_SEC ||
sec > MAX_FETCH_DIRTYRATE_TIME_SEC) {
return false;
}
return true;
}
static bool is_sample_pages_valid(int64_t pages)
{
return pages >= MIN_SAMPLE_PAGE_COUNT &&
pages <= MAX_SAMPLE_PAGE_COUNT;
}
static int dirtyrate_set_state(int *state, int old_state, int new_state)
{
assert(new_state < DIRTY_RATE_STATUS__MAX);
trace_dirtyrate_set_state(DirtyRateStatus_str(new_state));
if (qatomic_cmpxchg(state, old_state, new_state) == old_state) {
return 0;
} else {
return -1;
}
}
static struct DirtyRateInfo *query_dirty_rate_info(void)
{
int64_t dirty_rate = DirtyStat.dirty_rate;
struct DirtyRateInfo *info = g_malloc0(sizeof(DirtyRateInfo));
if (qatomic_read(&CalculatingState) == DIRTY_RATE_STATUS_MEASURED) {
info->has_dirty_rate = true;
info->dirty_rate = dirty_rate;
}
info->status = CalculatingState;
info->start_time = DirtyStat.start_time;
info->calc_time = DirtyStat.calc_time;
info->sample_pages = DirtyStat.sample_pages;
trace_query_dirty_rate_info(DirtyRateStatus_str(CalculatingState));
return info;
}
static void init_dirtyrate_stat(int64_t start_time, int64_t calc_time,
uint64_t sample_pages)
{
DirtyStat.total_dirty_samples = 0;
DirtyStat.total_sample_count = 0;
DirtyStat.total_block_mem_MB = 0;
DirtyStat.dirty_rate = -1;
DirtyStat.start_time = start_time;
DirtyStat.calc_time = calc_time;
DirtyStat.sample_pages = sample_pages;
}
static void update_dirtyrate_stat(struct RamblockDirtyInfo *info)
{
DirtyStat.total_dirty_samples += info->sample_dirty_count;
DirtyStat.total_sample_count += info->sample_pages_count;
/* size of total pages in MB */
DirtyStat.total_block_mem_MB += (info->ramblock_pages *
TARGET_PAGE_SIZE) >> 20;
}
static void update_dirtyrate(uint64_t msec)
{
uint64_t dirtyrate;
uint64_t total_dirty_samples = DirtyStat.total_dirty_samples;
uint64_t total_sample_count = DirtyStat.total_sample_count;
uint64_t total_block_mem_MB = DirtyStat.total_block_mem_MB;
dirtyrate = total_dirty_samples * total_block_mem_MB *
1000 / (total_sample_count * 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);
trace_get_ramblock_vfn_hash(info->idstr, vfn, crc);
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 void free_ramblock_dirty_info(struct RamblockDirtyInfo *infos, int count)
{
int i;
if (!infos) {
return;
}
for (i = 0; i < count; i++) {
g_free(infos[i].sample_page_vfn);
g_free(infos[i].hash_result);
}
g_free(infos);
}
static bool skip_sample_ramblock(RAMBlock *block)
{
/*
* Sample only blocks larger than MIN_RAMBLOCK_SIZE.
*/
if (qemu_ram_get_used_length(block) < (MIN_RAMBLOCK_SIZE << 10)) {
trace_skip_sample_ramblock(block->idstr,
qemu_ram_get_used_length(block));
return true;
}
return false;
}
static bool record_ramblock_hash_info(struct RamblockDirtyInfo **block_dinfo,
struct DirtyRateConfig config,
int *block_count)
{
struct RamblockDirtyInfo *info = NULL;
struct RamblockDirtyInfo *dinfo = NULL;
RAMBlock *block = NULL;
int total_count = 0;
int index = 0;
bool ret = false;
RAMBLOCK_FOREACH_MIGRATABLE(block) {
if (skip_sample_ramblock(block)) {
continue;
}
total_count++;
}
dinfo = g_try_malloc0_n(total_count, sizeof(struct RamblockDirtyInfo));
if (dinfo == NULL) {
goto out;
}
RAMBLOCK_FOREACH_MIGRATABLE(block) {
if (skip_sample_ramblock(block)) {
continue;
}
if (index >= total_count) {
break;
}
info = &dinfo[index];
get_ramblock_dirty_info(block, info, &config);
if (!save_ramblock_hash(info)) {
goto out;
}
index++;
}
ret = true;
out:
*block_count = index;
*block_dinfo = dinfo;
return ret;
}
static void calc_page_dirty_rate(struct RamblockDirtyInfo *info)
{
uint32_t crc;
int i;
for (i = 0; i < info->sample_pages_count; i++) {
crc = get_ramblock_vfn_hash(info, info->sample_page_vfn[i]);
if (crc != info->hash_result[i]) {
trace_calc_page_dirty_rate(info->idstr, crc, info->hash_result[i]);
info->sample_dirty_count++;
}
}
}
static struct RamblockDirtyInfo *
find_block_matched(RAMBlock *block, int count,
struct RamblockDirtyInfo *infos)
{
int i;
struct RamblockDirtyInfo *matched;
for (i = 0; i < count; i++) {
if (!strcmp(infos[i].idstr, qemu_ram_get_idstr(block))) {
break;
}
}
if (i == count) {
return NULL;
}
if (infos[i].ramblock_addr != qemu_ram_get_host_addr(block) ||
infos[i].ramblock_pages !=
(qemu_ram_get_used_length(block) >> TARGET_PAGE_BITS)) {
trace_find_page_matched(block->idstr);
return NULL;
}
matched = &infos[i];
return matched;
}
static bool compare_page_hash_info(struct RamblockDirtyInfo *info,
int block_count)
{
struct RamblockDirtyInfo *block_dinfo = NULL;
RAMBlock *block = NULL;
RAMBLOCK_FOREACH_MIGRATABLE(block) {
if (skip_sample_ramblock(block)) {
continue;
}
block_dinfo = find_block_matched(block, block_count, info);
if (block_dinfo == NULL) {
continue;
}
calc_page_dirty_rate(block_dinfo);
update_dirtyrate_stat(block_dinfo);
}
if (DirtyStat.total_sample_count == 0) {
return false;
}
return true;
}
static void calculate_dirtyrate(struct DirtyRateConfig config)
{
struct RamblockDirtyInfo *block_dinfo = NULL;
int block_count = 0;
int64_t msec = 0;
int64_t initial_time;
rcu_register_thread();
rcu_read_lock();
initial_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
if (!record_ramblock_hash_info(&block_dinfo, config, &block_count)) {
goto out;
}
rcu_read_unlock();
msec = config.sample_period_seconds * 1000;
msec = set_sample_page_period(msec, initial_time);
DirtyStat.start_time = initial_time / 1000;
DirtyStat.calc_time = msec / 1000;
rcu_read_lock();
if (!compare_page_hash_info(block_dinfo, block_count)) {
goto out;
}
update_dirtyrate(msec);
out:
rcu_read_unlock();
free_ramblock_dirty_info(block_dinfo, block_count);
rcu_unregister_thread();
}
void *get_dirtyrate_thread(void *arg)
{
struct DirtyRateConfig config = *(struct DirtyRateConfig *)arg;
int ret;
int64_t start_time;
int64_t calc_time;
uint64_t sample_pages;
ret = dirtyrate_set_state(&CalculatingState, DIRTY_RATE_STATUS_UNSTARTED,
DIRTY_RATE_STATUS_MEASURING);
if (ret == -1) {
error_report("change dirtyrate state failed.");
return NULL;
}
start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) / 1000;
calc_time = config.sample_period_seconds;
sample_pages = config.sample_pages_per_gigabytes;
init_dirtyrate_stat(start_time, calc_time, sample_pages);
calculate_dirtyrate(config);
ret = dirtyrate_set_state(&CalculatingState, DIRTY_RATE_STATUS_MEASURING,
DIRTY_RATE_STATUS_MEASURED);
if (ret == -1) {
error_report("change dirtyrate state failed.");
}
return NULL;
}
void qmp_calc_dirty_rate(int64_t calc_time, bool has_sample_pages,
int64_t sample_pages, Error **errp)
{
static struct DirtyRateConfig config;
QemuThread thread;
int ret;
/*
* If the dirty rate is already being measured, don't attempt to start.
*/
if (qatomic_read(&CalculatingState) == DIRTY_RATE_STATUS_MEASURING) {
error_setg(errp, "the dirty rate is already being measured.");
return;
}
if (!is_sample_period_valid(calc_time)) {
error_setg(errp, "calc-time is out of range[%d, %d].",
MIN_FETCH_DIRTYRATE_TIME_SEC,
MAX_FETCH_DIRTYRATE_TIME_SEC);
return;
}
if (has_sample_pages) {
if (!is_sample_pages_valid(sample_pages)) {
error_setg(errp, "sample-pages is out of range[%d, %d].",
MIN_SAMPLE_PAGE_COUNT,
MAX_SAMPLE_PAGE_COUNT);
return;
}
} else {
sample_pages = DIRTYRATE_DEFAULT_SAMPLE_PAGES;
}
/*
* Init calculation state as unstarted.
*/
ret = dirtyrate_set_state(&CalculatingState, CalculatingState,
DIRTY_RATE_STATUS_UNSTARTED);
if (ret == -1) {
error_setg(errp, "init dirty rate calculation state failed.");
return;
}
config.sample_period_seconds = calc_time;
config.sample_pages_per_gigabytes = sample_pages;
qemu_thread_create(&thread, "get_dirtyrate", get_dirtyrate_thread,
(void *)&config, QEMU_THREAD_DETACHED);
}
struct DirtyRateInfo *qmp_query_dirty_rate(Error **errp)
{
return query_dirty_rate_info();
}
void hmp_info_dirty_rate(Monitor *mon, const QDict *qdict)
{
DirtyRateInfo *info = query_dirty_rate_info();
monitor_printf(mon, "Status: %s\n",
DirtyRateStatus_str(info->status));
monitor_printf(mon, "Start Time: %"PRIi64" (ms)\n",
info->start_time);
monitor_printf(mon, "Sample Pages: %"PRIu64" (per GB)\n",
info->sample_pages);
monitor_printf(mon, "Period: %"PRIi64" (sec)\n",
info->calc_time);
monitor_printf(mon, "Dirty rate: ");
if (info->has_dirty_rate) {
monitor_printf(mon, "%"PRIi64" (MB/s)\n", info->dirty_rate);
} else {
monitor_printf(mon, "(not ready)\n");
}
g_free(info);
}
void hmp_calc_dirty_rate(Monitor *mon, const QDict *qdict)
{
int64_t sec = qdict_get_try_int(qdict, "second", 0);
int64_t sample_pages = qdict_get_try_int(qdict, "sample_pages_per_GB", -1);
bool has_sample_pages = (sample_pages != -1);
Error *err = NULL;
if (!sec) {
monitor_printf(mon, "Incorrect period length specified!\n");
return;
}
qmp_calc_dirty_rate(sec, has_sample_pages, sample_pages, &err);
if (err) {
hmp_handle_error(mon, err);
return;
}
monitor_printf(mon, "Starting dirty rate measurement with period %"PRIi64
" seconds\n", sec);
monitor_printf(mon, "[Please use 'info dirty_rate' to check results]\n");
}