migration/dirtyrate.c

   1 /*
   2  * Dirtyrate implement code
   3  *
   4  * Copyright (c) 2020 HUAWEI TECHNOLOGIES CO.,LTD.
   5  *
   6  * Authors:
   7  *  Chuan Zheng <zhengchuan@huawei.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  10  * See the COPYING file in the top-level directory.
  11  */
  12
  13 #include "qemu/osdep.h"
  14 #include "qemu/error-report.h"
  15 #include <zlib.h>
  16 #include "qapi/error.h"
  17 #include "cpu.h"
  18 #include "exec/ramblock.h"
  19 #include "exec/ram_addr.h"
  20 #include "qemu/rcu_queue.h"
  21 #include "qemu/main-loop.h"
  22 #include "qapi/qapi-commands-migration.h"
  23 #include "ram.h"
  24 #include "trace.h"
  25 #include "dirtyrate.h"
  26 #include "monitor/hmp.h"
  27 #include "monitor/monitor.h"
  28 #include "qapi/qmp/qdict.h"
  29 #include "sysemu/kvm.h"
  30 #include "sysemu/runstate.h"
  31 #include "exec/memory.h"
  32
  33 /*
  34  * total_dirty_pages is procted by BQL and is used
  35  * to stat dirty pages during the period of two
  36  * memory_global_dirty_log_sync
  37  */
  38 uint64_t total_dirty_pages;
  39
  40 typedef struct DirtyPageRecord {
  41     uint64_t start_pages;
  42     uint64_t end_pages;
  43 } DirtyPageRecord;
  44
  45 static int CalculatingState = DIRTY_RATE_STATUS_UNSTARTED;
  46 static struct DirtyRateStat DirtyStat;
  47 static DirtyRateMeasureMode dirtyrate_mode =
  48                 DIRTY_RATE_MEASURE_MODE_PAGE_SAMPLING;
  49
  50 static int64_t dirty_stat_wait(int64_t msec, int64_t initial_time)
  51 {
  52     int64_t current_time;
  53
  54     current_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
  55     if ((current_time - initial_time) >= msec) {
  56         msec = current_time - initial_time;
  57     } else {
  58         g_usleep((msec + initial_time - current_time) * 1000);
  59     }
  60
  61     return msec;
  62 }
  63
  64 static inline void record_dirtypages(DirtyPageRecord *dirty_pages,
  65                                      CPUState *cpu, bool start)
  66 {
  67     if (start) {
  68         dirty_pages[cpu->cpu_index].start_pages = cpu->dirty_pages;
  69     } else {
  70         dirty_pages[cpu->cpu_index].end_pages = cpu->dirty_pages;
  71     }
  72 }
  73
  74 static int64_t do_calculate_dirtyrate(DirtyPageRecord dirty_pages,
  75                                       int64_t calc_time_ms)
  76 {
  77     uint64_t memory_size_MB;
  78     uint64_t increased_dirty_pages =
  79         dirty_pages.end_pages - dirty_pages.start_pages;
  80
  81     memory_size_MB = (increased_dirty_pages * TARGET_PAGE_SIZE) >> 20;
  82
  83     return memory_size_MB * 1000 / calc_time_ms;
  84 }
  85
  86 void global_dirty_log_change(unsigned int flag, bool start)
  87 {
  88     qemu_mutex_lock_iothread();
  89     if (start) {
  90         memory_global_dirty_log_start(flag);
  91     } else {
  92         memory_global_dirty_log_stop(flag);
  93     }
  94     qemu_mutex_unlock_iothread();
  95 }
  96
  97 /*
  98  * global_dirty_log_sync
  99  * 1. sync dirty log from kvm
 100  * 2. stop dirty tracking if needed.
 101  */
 102 static void global_dirty_log_sync(unsigned int flag, bool one_shot)
 103 {
 104     qemu_mutex_lock_iothread();
 105     memory_global_dirty_log_sync();
 106     if (one_shot) {
 107         memory_global_dirty_log_stop(flag);
 108     }
 109     qemu_mutex_unlock_iothread();
 110 }
 111
 112 static DirtyPageRecord *vcpu_dirty_stat_alloc(VcpuStat *stat)
 113 {
 114     CPUState *cpu;
 115     int nvcpu = 0;
 116
 117     CPU_FOREACH(cpu) {
 118         nvcpu++;
 119     }
 120
 121     stat->nvcpu = nvcpu;
 122     stat->rates = g_new0(DirtyRateVcpu, nvcpu);
 123
 124     return g_new0(DirtyPageRecord, nvcpu);
 125 }
 126
 127 static void vcpu_dirty_stat_collect(VcpuStat *stat,
 128                                     DirtyPageRecord *records,
 129                                     bool start)
 130 {
 131     CPUState *cpu;
 132
 133     CPU_FOREACH(cpu) {
 134         record_dirtypages(records, cpu, start);
 135     }
 136 }
 137
 138 int64_t vcpu_calculate_dirtyrate(int64_t calc_time_ms,
 139                                  VcpuStat *stat,
 140                                  unsigned int flag,
 141                                  bool one_shot)
 142 {
 143     DirtyPageRecord *records;
 144     int64_t init_time_ms;
 145     int64_t duration;
 146     int64_t dirtyrate;
 147     int i = 0;
 148     unsigned int gen_id;
 149
 150 retry:
 151     init_time_ms = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
 152
 153     cpu_list_lock();
 154     gen_id = cpu_list_generation_id_get();
 155     records = vcpu_dirty_stat_alloc(stat);
 156     vcpu_dirty_stat_collect(stat, records, true);
 157     cpu_list_unlock();
 158
 159     duration = dirty_stat_wait(calc_time_ms, init_time_ms);
 160
 161     global_dirty_log_sync(flag, one_shot);
 162
 163     cpu_list_lock();
 164     if (gen_id != cpu_list_generation_id_get()) {
 165         g_free(records);
 166         g_free(stat->rates);
 167         cpu_list_unlock();
 168         goto retry;
 169     }
 170     vcpu_dirty_stat_collect(stat, records, false);
 171     cpu_list_unlock();
 172
 173     for (i = 0; i < stat->nvcpu; i++) {
 174         dirtyrate = do_calculate_dirtyrate(records[i], duration);
 175
 176         stat->rates[i].id = i;
 177         stat->rates[i].dirty_rate = dirtyrate;
 178
 179         trace_dirtyrate_do_calculate_vcpu(i, dirtyrate);
 180     }
 181
 182     g_free(records);
 183
 184     return duration;
 185 }
 186
 187 static bool is_sample_period_valid(int64_t sec)
 188 {
 189     if (sec < MIN_FETCH_DIRTYRATE_TIME_SEC ||
 190         sec > MAX_FETCH_DIRTYRATE_TIME_SEC) {
 191         return false;
 192     }
 193
 194     return true;
 195 }
 196
 197 static bool is_sample_pages_valid(int64_t pages)
 198 {
 199     return pages >= MIN_SAMPLE_PAGE_COUNT &&
 200            pages <= MAX_SAMPLE_PAGE_COUNT;
 201 }
 202
 203 static int dirtyrate_set_state(int *state, int old_state, int new_state)
 204 {
 205     assert(new_state < DIRTY_RATE_STATUS__MAX);
 206     trace_dirtyrate_set_state(DirtyRateStatus_str(new_state));
 207     if (qatomic_cmpxchg(state, old_state, new_state) == old_state) {
 208         return 0;
 209     } else {
 210         return -1;
 211     }
 212 }
 213
 214 static struct DirtyRateInfo *query_dirty_rate_info(void)
 215 {
 216     int i;
 217     int64_t dirty_rate = DirtyStat.dirty_rate;
 218     struct DirtyRateInfo *info = g_new0(DirtyRateInfo, 1);
 219     DirtyRateVcpuList *head = NULL, **tail = &head;
 220
 221     info->status = CalculatingState;
 222     info->start_time = DirtyStat.start_time;
 223     info->calc_time = DirtyStat.calc_time;
 224     info->sample_pages = DirtyStat.sample_pages;
 225     info->mode = dirtyrate_mode;
 226
 227     if (qatomic_read(&CalculatingState) == DIRTY_RATE_STATUS_MEASURED) {
 228         info->has_dirty_rate = true;
 229         info->dirty_rate = dirty_rate;
 230
 231         if (dirtyrate_mode == DIRTY_RATE_MEASURE_MODE_DIRTY_RING) {
 232             /*
 233              * set sample_pages with 0 to indicate page sampling
 234              * isn't enabled
 235              **/
 236             info->sample_pages = 0;
 237             info->has_vcpu_dirty_rate = true;
 238             for (i = 0; i < DirtyStat.dirty_ring.nvcpu; i++) {
 239                 DirtyRateVcpu *rate = g_new0(DirtyRateVcpu, 1);
 240                 rate->id = DirtyStat.dirty_ring.rates[i].id;
 241                 rate->dirty_rate = DirtyStat.dirty_ring.rates[i].dirty_rate;
 242                 QAPI_LIST_APPEND(tail, rate);
 243             }
 244             info->vcpu_dirty_rate = head;
 245         }
 246
 247         if (dirtyrate_mode == DIRTY_RATE_MEASURE_MODE_DIRTY_BITMAP) {
 248             info->sample_pages = 0;
 249         }
 250     }
 251
 252     trace_query_dirty_rate_info(DirtyRateStatus_str(CalculatingState));
 253
 254     return info;
 255 }
 256
 257 static void init_dirtyrate_stat(int64_t start_time,
 258                                 struct DirtyRateConfig config)
 259 {
 260     DirtyStat.dirty_rate = -1;
 261     DirtyStat.start_time = start_time;
 262     DirtyStat.calc_time = config.sample_period_seconds;
 263     DirtyStat.sample_pages = config.sample_pages_per_gigabytes;
 264
 265     switch (config.mode) {
 266     case DIRTY_RATE_MEASURE_MODE_PAGE_SAMPLING:
 267         DirtyStat.page_sampling.total_dirty_samples = 0;
 268         DirtyStat.page_sampling.total_sample_count = 0;
 269         DirtyStat.page_sampling.total_block_mem_MB = 0;
 270         break;
 271     case DIRTY_RATE_MEASURE_MODE_DIRTY_RING:
 272         DirtyStat.dirty_ring.nvcpu = -1;
 273         DirtyStat.dirty_ring.rates = NULL;
 274         break;
 275     default:
 276         break;
 277     }
 278 }
 279
 280 static void cleanup_dirtyrate_stat(struct DirtyRateConfig config)
 281 {
 282     /* last calc-dirty-rate qmp use dirty ring mode */
 283     if (dirtyrate_mode == DIRTY_RATE_MEASURE_MODE_DIRTY_RING) {
 284         free(DirtyStat.dirty_ring.rates);
 285         DirtyStat.dirty_ring.rates = NULL;
 286     }
 287 }
 288
 289 static void update_dirtyrate_stat(struct RamblockDirtyInfo *info)
 290 {
 291     DirtyStat.page_sampling.total_dirty_samples += info->sample_dirty_count;
 292     DirtyStat.page_sampling.total_sample_count += info->sample_pages_count;
 293     /* size of total pages in MB */
 294     DirtyStat.page_sampling.total_block_mem_MB += (info->ramblock_pages *
 295                                                    TARGET_PAGE_SIZE) >> 20;
 296 }
 297
 298 static void update_dirtyrate(uint64_t msec)
 299 {
 300     uint64_t dirtyrate;
 301     uint64_t total_dirty_samples = DirtyStat.page_sampling.total_dirty_samples;
 302     uint64_t total_sample_count = DirtyStat.page_sampling.total_sample_count;
 303     uint64_t total_block_mem_MB = DirtyStat.page_sampling.total_block_mem_MB;
 304
 305     dirtyrate = total_dirty_samples * total_block_mem_MB *
 306                 1000 / (total_sample_count * msec);
 307
 308     DirtyStat.dirty_rate = dirtyrate;
 309 }
 310
 311 /*
 312  * get hash result for the sampled memory with length of TARGET_PAGE_SIZE
 313  * in ramblock, which starts from ramblock base address.
 314  */
 315 static uint32_t get_ramblock_vfn_hash(struct RamblockDirtyInfo *info,
 316                                       uint64_t vfn)
 317 {
 318     uint32_t crc;
 319
 320     crc = crc32(0, (info->ramblock_addr +
 321                 vfn * TARGET_PAGE_SIZE), TARGET_PAGE_SIZE);
 322
 323     trace_get_ramblock_vfn_hash(info->idstr, vfn, crc);
 324     return crc;
 325 }
 326
 327 static bool save_ramblock_hash(struct RamblockDirtyInfo *info)
 328 {
 329     unsigned int sample_pages_count;
 330     int i;
 331     GRand *rand;
 332
 333     sample_pages_count = info->sample_pages_count;
 334
 335     /* ramblock size less than one page, return success to skip this ramblock */
 336     if (unlikely(info->ramblock_pages == 0 || sample_pages_count == 0)) {
 337         return true;
 338     }
 339
 340     info->hash_result = g_try_malloc0_n(sample_pages_count,
 341                                         sizeof(uint32_t));
 342     if (!info->hash_result) {
 343         return false;
 344     }
 345
 346     info->sample_page_vfn = g_try_malloc0_n(sample_pages_count,
 347                                             sizeof(uint64_t));
 348     if (!info->sample_page_vfn) {
 349         g_free(info->hash_result);
 350         return false;
 351     }
 352
 353     rand  = g_rand_new();
 354     for (i = 0; i < sample_pages_count; i++) {
 355         info->sample_page_vfn[i] = g_rand_int_range(rand, 0,
 356                                                     info->ramblock_pages - 1);
 357         info->hash_result[i] = get_ramblock_vfn_hash(info,
 358                                                      info->sample_page_vfn[i]);
 359     }
 360     g_rand_free(rand);
 361
 362     return true;
 363 }
 364
 365 static void get_ramblock_dirty_info(RAMBlock *block,
 366                                     struct RamblockDirtyInfo *info,
 367                                     struct DirtyRateConfig *config)
 368 {
 369     uint64_t sample_pages_per_gigabytes = config->sample_pages_per_gigabytes;
 370
 371     /* Right shift 30 bits to calc ramblock size in GB */
 372     info->sample_pages_count = (qemu_ram_get_used_length(block) *
 373                                 sample_pages_per_gigabytes) >> 30;
 374     /* Right shift TARGET_PAGE_BITS to calc page count */
 375     info->ramblock_pages = qemu_ram_get_used_length(block) >>
 376                            TARGET_PAGE_BITS;
 377     info->ramblock_addr = qemu_ram_get_host_addr(block);
 378     strcpy(info->idstr, qemu_ram_get_idstr(block));
 379 }
 380
 381 static void free_ramblock_dirty_info(struct RamblockDirtyInfo *infos, int count)
 382 {
 383     int i;
 384
 385     if (!infos) {
 386         return;
 387     }
 388
 389     for (i = 0; i < count; i++) {
 390         g_free(infos[i].sample_page_vfn);
 391         g_free(infos[i].hash_result);
 392     }
 393     g_free(infos);
 394 }
 395
 396 static bool skip_sample_ramblock(RAMBlock *block)
 397 {
 398     /*
 399      * Sample only blocks larger than MIN_RAMBLOCK_SIZE.
 400      */
 401     if (qemu_ram_get_used_length(block) < (MIN_RAMBLOCK_SIZE << 10)) {
 402         trace_skip_sample_ramblock(block->idstr,
 403                                    qemu_ram_get_used_length(block));
 404         return true;
 405     }
 406
 407     return false;
 408 }
 409
 410 static bool record_ramblock_hash_info(struct RamblockDirtyInfo **block_dinfo,
 411                                       struct DirtyRateConfig config,
 412                                       int *block_count)
 413 {
 414     struct RamblockDirtyInfo *info = NULL;
 415     struct RamblockDirtyInfo *dinfo = NULL;
 416     RAMBlock *block = NULL;
 417     int total_count = 0;
 418     int index = 0;
 419     bool ret = false;
 420
 421     RAMBLOCK_FOREACH_MIGRATABLE(block) {
 422         if (skip_sample_ramblock(block)) {
 423             continue;
 424         }
 425         total_count++;
 426     }
 427
 428     dinfo = g_try_malloc0_n(total_count, sizeof(struct RamblockDirtyInfo));
 429     if (dinfo == NULL) {
 430         goto out;
 431     }
 432
 433     RAMBLOCK_FOREACH_MIGRATABLE(block) {
 434         if (skip_sample_ramblock(block)) {
 435             continue;
 436         }
 437         if (index >= total_count) {
 438             break;
 439         }
 440         info = &dinfo[index];
 441         get_ramblock_dirty_info(block, info, &config);
 442         if (!save_ramblock_hash(info)) {
 443             goto out;
 444         }
 445         index++;
 446     }
 447     ret = true;
 448
 449 out:
 450     *block_count = index;
 451     *block_dinfo = dinfo;
 452     return ret;
 453 }
 454
 455 static void calc_page_dirty_rate(struct RamblockDirtyInfo *info)
 456 {
 457     uint32_t crc;
 458     int i;
 459
 460     for (i = 0; i < info->sample_pages_count; i++) {
 461         crc = get_ramblock_vfn_hash(info, info->sample_page_vfn[i]);
 462         if (crc != info->hash_result[i]) {
 463             trace_calc_page_dirty_rate(info->idstr, crc, info->hash_result[i]);
 464             info->sample_dirty_count++;
 465         }
 466     }
 467 }
 468
 469 static struct RamblockDirtyInfo *
 470 find_block_matched(RAMBlock *block, int count,
 471                   struct RamblockDirtyInfo *infos)
 472 {
 473     int i;
 474
 475     for (i = 0; i < count; i++) {
 476         if (!strcmp(infos[i].idstr, qemu_ram_get_idstr(block))) {
 477             break;
 478         }
 479     }
 480
 481     if (i == count) {
 482         return NULL;
 483     }
 484
 485     if (infos[i].ramblock_addr != qemu_ram_get_host_addr(block) ||
 486         infos[i].ramblock_pages !=
 487             (qemu_ram_get_used_length(block) >> TARGET_PAGE_BITS)) {
 488         trace_find_page_matched(block->idstr);
 489         return NULL;
 490     }
 491
 492     return &infos[i];
 493 }
 494
 495 static bool compare_page_hash_info(struct RamblockDirtyInfo *info,
 496                                   int block_count)
 497 {
 498     struct RamblockDirtyInfo *block_dinfo = NULL;
 499     RAMBlock *block = NULL;
 500
 501     RAMBLOCK_FOREACH_MIGRATABLE(block) {
 502         if (skip_sample_ramblock(block)) {
 503             continue;
 504         }
 505         block_dinfo = find_block_matched(block, block_count, info);
 506         if (block_dinfo == NULL) {
 507             continue;
 508         }
 509         calc_page_dirty_rate(block_dinfo);
 510         update_dirtyrate_stat(block_dinfo);
 511     }
 512
 513     if (DirtyStat.page_sampling.total_sample_count == 0) {
 514         return false;
 515     }
 516
 517     return true;
 518 }
 519
 520 static inline void record_dirtypages_bitmap(DirtyPageRecord *dirty_pages,
 521                                             bool start)
 522 {
 523     if (start) {
 524         dirty_pages->start_pages = total_dirty_pages;
 525     } else {
 526         dirty_pages->end_pages = total_dirty_pages;
 527     }
 528 }
 529
 530 static inline void dirtyrate_manual_reset_protect(void)
 531 {
 532     RAMBlock *block = NULL;
 533
 534     WITH_RCU_READ_LOCK_GUARD() {
 535         RAMBLOCK_FOREACH_MIGRATABLE(block) {
 536             memory_region_clear_dirty_bitmap(block->mr, 0,
 537                                              block->used_length);
 538         }
 539     }
 540 }
 541
 542 static void calculate_dirtyrate_dirty_bitmap(struct DirtyRateConfig config)
 543 {
 544     int64_t msec = 0;
 545     int64_t start_time;
 546     DirtyPageRecord dirty_pages;
 547
 548     qemu_mutex_lock_iothread();
 549     memory_global_dirty_log_start(GLOBAL_DIRTY_DIRTY_RATE);
 550
 551     /*
 552      * 1'round of log sync may return all 1 bits with
 553      * KVM_DIRTY_LOG_INITIALLY_SET enable
 554      * skip it unconditionally and start dirty tracking
 555      * from 2'round of log sync
 556      */
 557     memory_global_dirty_log_sync();
 558
 559     /*
 560      * reset page protect manually and unconditionally.
 561      * this make sure kvm dirty log be cleared if
 562      * KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE cap is enabled.
 563      */
 564     dirtyrate_manual_reset_protect();
 565     qemu_mutex_unlock_iothread();
 566
 567     record_dirtypages_bitmap(&dirty_pages, true);
 568
 569     start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
 570     DirtyStat.start_time = start_time / 1000;
 571
 572     msec = config.sample_period_seconds * 1000;
 573     msec = dirty_stat_wait(msec, start_time);
 574     DirtyStat.calc_time = msec / 1000;
 575
 576     /*
 577      * do two things.
 578      * 1. fetch dirty bitmap from kvm
 579      * 2. stop dirty tracking
 580      */
 581     global_dirty_log_sync(GLOBAL_DIRTY_DIRTY_RATE, true);
 582
 583     record_dirtypages_bitmap(&dirty_pages, false);
 584
 585     DirtyStat.dirty_rate = do_calculate_dirtyrate(dirty_pages, msec);
 586 }
 587
 588 static void calculate_dirtyrate_dirty_ring(struct DirtyRateConfig config)
 589 {
 590     int64_t duration;
 591     uint64_t dirtyrate = 0;
 592     uint64_t dirtyrate_sum = 0;
 593     int i = 0;
 594
 595     /* start log sync */
 596     global_dirty_log_change(GLOBAL_DIRTY_DIRTY_RATE, true);
 597
 598     DirtyStat.start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) / 1000;
 599
 600     /* calculate vcpu dirtyrate */
 601     duration = vcpu_calculate_dirtyrate(config.sample_period_seconds * 1000,
 602                                         &DirtyStat.dirty_ring,
 603                                         GLOBAL_DIRTY_DIRTY_RATE,
 604                                         true);
 605
 606     DirtyStat.calc_time = duration / 1000;
 607
 608     /* calculate vm dirtyrate */
 609     for (i = 0; i < DirtyStat.dirty_ring.nvcpu; i++) {
 610         dirtyrate = DirtyStat.dirty_ring.rates[i].dirty_rate;
 611         DirtyStat.dirty_ring.rates[i].dirty_rate = dirtyrate;
 612         dirtyrate_sum += dirtyrate;
 613     }
 614
 615     DirtyStat.dirty_rate = dirtyrate_sum;
 616 }
 617
 618 static void calculate_dirtyrate_sample_vm(struct DirtyRateConfig config)
 619 {
 620     struct RamblockDirtyInfo *block_dinfo = NULL;
 621     int block_count = 0;
 622     int64_t msec = 0;
 623     int64_t initial_time;
 624
 625     rcu_read_lock();
 626     initial_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
 627     if (!record_ramblock_hash_info(&block_dinfo, config, &block_count)) {
 628         goto out;
 629     }
 630     rcu_read_unlock();
 631
 632     msec = config.sample_period_seconds * 1000;
 633     msec = dirty_stat_wait(msec, initial_time);
 634     DirtyStat.start_time = initial_time / 1000;
 635     DirtyStat.calc_time = msec / 1000;
 636
 637     rcu_read_lock();
 638     if (!compare_page_hash_info(block_dinfo, block_count)) {
 639         goto out;
 640     }
 641
 642     update_dirtyrate(msec);
 643
 644 out:
 645     rcu_read_unlock();
 646     free_ramblock_dirty_info(block_dinfo, block_count);
 647 }
 648
 649 static void calculate_dirtyrate(struct DirtyRateConfig config)
 650 {
 651     if (config.mode == DIRTY_RATE_MEASURE_MODE_DIRTY_BITMAP) {
 652         calculate_dirtyrate_dirty_bitmap(config);
 653     } else if (config.mode == DIRTY_RATE_MEASURE_MODE_DIRTY_RING) {
 654         calculate_dirtyrate_dirty_ring(config);
 655     } else {
 656         calculate_dirtyrate_sample_vm(config);
 657     }
 658
 659     trace_dirtyrate_calculate(DirtyStat.dirty_rate);
 660 }
 661
 662 void *get_dirtyrate_thread(void *arg)
 663 {
 664     struct DirtyRateConfig config = *(struct DirtyRateConfig *)arg;
 665     int ret;
 666     rcu_register_thread();
 667
 668     ret = dirtyrate_set_state(&CalculatingState, DIRTY_RATE_STATUS_UNSTARTED,
 669                               DIRTY_RATE_STATUS_MEASURING);
 670     if (ret == -1) {
 671         error_report("change dirtyrate state failed.");
 672         return NULL;
 673     }
 674
 675     calculate_dirtyrate(config);
 676
 677     ret = dirtyrate_set_state(&CalculatingState, DIRTY_RATE_STATUS_MEASURING,
 678                               DIRTY_RATE_STATUS_MEASURED);
 679     if (ret == -1) {
 680         error_report("change dirtyrate state failed.");
 681     }
 682
 683     rcu_unregister_thread();
 684     return NULL;
 685 }
 686
 687 void qmp_calc_dirty_rate(int64_t calc_time,
 688                          bool has_sample_pages,
 689                          int64_t sample_pages,
 690                          bool has_mode,
 691                          DirtyRateMeasureMode mode,
 692                          Error **errp)
 693 {
 694     static struct DirtyRateConfig config;
 695     QemuThread thread;
 696     int ret;
 697     int64_t start_time;
 698
 699     /*
 700      * If the dirty rate is already being measured, don't attempt to start.
 701      */
 702     if (qatomic_read(&CalculatingState) == DIRTY_RATE_STATUS_MEASURING) {
 703         error_setg(errp, "the dirty rate is already being measured.");
 704         return;
 705     }
 706
 707     if (!is_sample_period_valid(calc_time)) {
 708         error_setg(errp, "calc-time is out of range[%d, %d].",
 709                          MIN_FETCH_DIRTYRATE_TIME_SEC,
 710                          MAX_FETCH_DIRTYRATE_TIME_SEC);
 711         return;
 712     }
 713
 714     if (!has_mode) {
 715         mode =  DIRTY_RATE_MEASURE_MODE_PAGE_SAMPLING;
 716     }
 717
 718     if (has_sample_pages && mode != DIRTY_RATE_MEASURE_MODE_PAGE_SAMPLING) {
 719         error_setg(errp, "sample-pages is used only in page-sampling mode");
 720         return;
 721     }
 722
 723     if (has_sample_pages) {
 724         if (!is_sample_pages_valid(sample_pages)) {
 725             error_setg(errp, "sample-pages is out of range[%d, %d].",
 726                             MIN_SAMPLE_PAGE_COUNT,
 727                             MAX_SAMPLE_PAGE_COUNT);
 728             return;
 729         }
 730     } else {
 731         sample_pages = DIRTYRATE_DEFAULT_SAMPLE_PAGES;
 732     }
 733
 734     /*
 735      * dirty ring mode only works when kvm dirty ring is enabled.
 736      * on the contrary, dirty bitmap mode is not.
 737      */
 738     if (((mode == DIRTY_RATE_MEASURE_MODE_DIRTY_RING) &&
 739         !kvm_dirty_ring_enabled()) ||
 740         ((mode == DIRTY_RATE_MEASURE_MODE_DIRTY_BITMAP) &&
 741          kvm_dirty_ring_enabled())) {
 742         error_setg(errp, "mode %s is not enabled, use other method instead.",
 743                          DirtyRateMeasureMode_str(mode));
 744          return;
 745     }
 746
 747     /*
 748      * Init calculation state as unstarted.
 749      */
 750     ret = dirtyrate_set_state(&CalculatingState, CalculatingState,
 751                               DIRTY_RATE_STATUS_UNSTARTED);
 752     if (ret == -1) {
 753         error_setg(errp, "init dirty rate calculation state failed.");
 754         return;
 755     }
 756
 757     config.sample_period_seconds = calc_time;
 758     config.sample_pages_per_gigabytes = sample_pages;
 759     config.mode = mode;
 760
 761     cleanup_dirtyrate_stat(config);
 762
 763     /*
 764      * update dirty rate mode so that we can figure out what mode has
 765      * been used in last calculation
 766      **/
 767     dirtyrate_mode = mode;
 768
 769     start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) / 1000;
 770     init_dirtyrate_stat(start_time, config);
 771
 772     qemu_thread_create(&thread, "get_dirtyrate", get_dirtyrate_thread,
 773                        (void *)&config, QEMU_THREAD_DETACHED);
 774 }
 775
 776 struct DirtyRateInfo *qmp_query_dirty_rate(Error **errp)
 777 {
 778     return query_dirty_rate_info();
 779 }
 780
 781 void hmp_info_dirty_rate(Monitor *mon, const QDict *qdict)
 782 {
 783     DirtyRateInfo *info = query_dirty_rate_info();
 784
 785     monitor_printf(mon, "Status: %s\n",
 786                    DirtyRateStatus_str(info->status));
 787     monitor_printf(mon, "Start Time: %"PRIi64" (ms)\n",
 788                    info->start_time);
 789     if (info->mode == DIRTY_RATE_MEASURE_MODE_PAGE_SAMPLING) {
 790         monitor_printf(mon, "Sample Pages: %"PRIu64" (per GB)\n",
 791                        info->sample_pages);
 792     }
 793     monitor_printf(mon, "Period: %"PRIi64" (sec)\n",
 794                    info->calc_time);
 795     monitor_printf(mon, "Mode: %s\n",
 796                    DirtyRateMeasureMode_str(info->mode));
 797     monitor_printf(mon, "Dirty rate: ");
 798     if (info->has_dirty_rate) {
 799         monitor_printf(mon, "%"PRIi64" (MB/s)\n", info->dirty_rate);
 800         if (info->has_vcpu_dirty_rate) {
 801             DirtyRateVcpuList *rate, *head = info->vcpu_dirty_rate;
 802             for (rate = head; rate != NULL; rate = rate->next) {
 803                 monitor_printf(mon, "vcpu[%"PRIi64"], Dirty rate: %"PRIi64
 804                                " (MB/s)\n", rate->value->id,
 805                                rate->value->dirty_rate);
 806             }
 807         }
 808     } else {
 809         monitor_printf(mon, "(not ready)\n");
 810     }
 811
 812     qapi_free_DirtyRateVcpuList(info->vcpu_dirty_rate);
 813     g_free(info);
 814 }
 815
 816 void hmp_calc_dirty_rate(Monitor *mon, const QDict *qdict)
 817 {
 818     int64_t sec = qdict_get_try_int(qdict, "second", 0);
 819     int64_t sample_pages = qdict_get_try_int(qdict, "sample_pages_per_GB", -1);
 820     bool has_sample_pages = (sample_pages != -1);
 821     bool dirty_ring = qdict_get_try_bool(qdict, "dirty_ring", false);
 822     bool dirty_bitmap = qdict_get_try_bool(qdict, "dirty_bitmap", false);
 823     DirtyRateMeasureMode mode = DIRTY_RATE_MEASURE_MODE_PAGE_SAMPLING;
 824     Error *err = NULL;
 825
 826     if (!sec) {
 827         monitor_printf(mon, "Incorrect period length specified!\n");
 828         return;
 829     }
 830
 831     if (dirty_ring && dirty_bitmap) {
 832         monitor_printf(mon, "Either dirty ring or dirty bitmap "
 833                        "can be specified!\n");
 834         return;
 835     }
 836
 837     if (dirty_bitmap) {
 838         mode = DIRTY_RATE_MEASURE_MODE_DIRTY_BITMAP;
 839     } else if (dirty_ring) {
 840         mode = DIRTY_RATE_MEASURE_MODE_DIRTY_RING;
 841     }
 842
 843     qmp_calc_dirty_rate(sec, has_sample_pages, sample_pages, true,
 844                         mode, &err);
 845     if (err) {
 846         hmp_handle_error(mon, err);
 847         return;
 848     }
 849
 850     monitor_printf(mon, "Starting dirty rate measurement with period %"PRIi64
 851                    " seconds\n", sec);
 852     monitor_printf(mon, "[Please use 'info dirty_rate' to check results]\n");
 853 }