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 "hw/core/cpu.h"
  17 #include "qapi/error.h"
  18 #include "exec/ramblock.h"
  19 #include "exec/target_page.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 #include "qemu/xxhash.h"
  33
  34 /*
  35  * total_dirty_pages is procted by BQL and is used
  36  * to stat dirty pages during the period of two
  37  * memory_global_dirty_log_sync
  38  */
  39 uint64_t total_dirty_pages;
  40
  41 typedef struct DirtyPageRecord {
  42     uint64_t start_pages;
  43     uint64_t end_pages;
  44 } DirtyPageRecord;
  45
  46 static int CalculatingState = DIRTY_RATE_STATUS_UNSTARTED;
  47 static struct DirtyRateStat DirtyStat;
  48 static DirtyRateMeasureMode dirtyrate_mode =
  49                 DIRTY_RATE_MEASURE_MODE_PAGE_SAMPLING;
  50
  51 static int64_t dirty_stat_wait(int64_t msec, int64_t initial_time)
  52 {
  53     int64_t current_time;
  54
  55     current_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
  56     if ((current_time - initial_time) >= msec) {
  57         msec = current_time - initial_time;
  58     } else {
  59         g_usleep((msec + initial_time - current_time) * 1000);
  60         /* g_usleep may overshoot */
  61         msec = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) - initial_time;
  62     }
  63
  64     return msec;
  65 }
  66
  67 static inline void record_dirtypages(DirtyPageRecord *dirty_pages,
  68                                      CPUState *cpu, bool start)
  69 {
  70     if (start) {
  71         dirty_pages[cpu->cpu_index].start_pages = cpu->dirty_pages;
  72     } else {
  73         dirty_pages[cpu->cpu_index].end_pages = cpu->dirty_pages;
  74     }
  75 }
  76
  77 static int64_t do_calculate_dirtyrate(DirtyPageRecord dirty_pages,
  78                                       int64_t calc_time_ms)
  79 {
  80     uint64_t increased_dirty_pages =
  81         dirty_pages.end_pages - dirty_pages.start_pages;
  82
  83     /*
  84      * multiply by 1000ms/s _before_ converting down to megabytes
  85      * to avoid losing precision
  86      */
  87     return qemu_target_pages_to_MiB(increased_dirty_pages * 1000) /
  88         calc_time_ms;
  89 }
  90
  91 void global_dirty_log_change(unsigned int flag, bool start)
  92 {
  93     qemu_mutex_lock_iothread();
  94     if (start) {
  95         memory_global_dirty_log_start(flag);
  96     } else {
  97         memory_global_dirty_log_stop(flag);
  98     }
  99     qemu_mutex_unlock_iothread();
 100 }
 101
 102 /*
 103  * global_dirty_log_sync
 104  * 1. sync dirty log from kvm
 105  * 2. stop dirty tracking if needed.
 106  */
 107 static void global_dirty_log_sync(unsigned int flag, bool one_shot)
 108 {
 109     qemu_mutex_lock_iothread();
 110     memory_global_dirty_log_sync(false);
 111     if (one_shot) {
 112         memory_global_dirty_log_stop(flag);
 113     }
 114     qemu_mutex_unlock_iothread();
 115 }
 116
 117 static DirtyPageRecord *vcpu_dirty_stat_alloc(VcpuStat *stat)
 118 {
 119     CPUState *cpu;
 120     int nvcpu = 0;
 121
 122     CPU_FOREACH(cpu) {
 123         nvcpu++;
 124     }
 125
 126     stat->nvcpu = nvcpu;
 127     stat->rates = g_new0(DirtyRateVcpu, nvcpu);
 128
 129     return g_new0(DirtyPageRecord, nvcpu);
 130 }
 131
 132 static void vcpu_dirty_stat_collect(VcpuStat *stat,
 133                                     DirtyPageRecord *records,
 134                                     bool start)
 135 {
 136     CPUState *cpu;
 137
 138     CPU_FOREACH(cpu) {
 139         record_dirtypages(records, cpu, start);
 140     }
 141 }
 142
 143 int64_t vcpu_calculate_dirtyrate(int64_t calc_time_ms,
 144                                  VcpuStat *stat,
 145                                  unsigned int flag,
 146                                  bool one_shot)
 147 {
 148     DirtyPageRecord *records;
 149     int64_t init_time_ms;
 150     int64_t duration;
 151     int64_t dirtyrate;
 152     int i = 0;
 153     unsigned int gen_id;
 154
 155 retry:
 156     init_time_ms = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
 157
 158     WITH_QEMU_LOCK_GUARD(&qemu_cpu_list_lock) {
 159         gen_id = cpu_list_generation_id_get();
 160         records = vcpu_dirty_stat_alloc(stat);
 161         vcpu_dirty_stat_collect(stat, records, true);
 162     }
 163
 164     duration = dirty_stat_wait(calc_time_ms, init_time_ms);
 165
 166     global_dirty_log_sync(flag, one_shot);
 167
 168     WITH_QEMU_LOCK_GUARD(&qemu_cpu_list_lock) {
 169         if (gen_id != cpu_list_generation_id_get()) {
 170             g_free(records);
 171             g_free(stat->rates);
 172             cpu_list_unlock();
 173             goto retry;
 174         }
 175         vcpu_dirty_stat_collect(stat, records, false);
 176     }
 177
 178     for (i = 0; i < stat->nvcpu; i++) {
 179         dirtyrate = do_calculate_dirtyrate(records[i], duration);
 180
 181         stat->rates[i].id = i;
 182         stat->rates[i].dirty_rate = dirtyrate;
 183
 184         trace_dirtyrate_do_calculate_vcpu(i, dirtyrate);
 185     }
 186
 187     g_free(records);
 188
 189     return duration;
 190 }
 191
 192 static bool is_calc_time_valid(int64_t msec)
 193 {
 194     if ((msec < MIN_CALC_TIME_MS) || (msec > MAX_CALC_TIME_MS)) {
 195         return false;
 196     }
 197
 198     return true;
 199 }
 200
 201 static bool is_sample_pages_valid(int64_t pages)
 202 {
 203     return pages >= MIN_SAMPLE_PAGE_COUNT &&
 204            pages <= MAX_SAMPLE_PAGE_COUNT;
 205 }
 206
 207 static int dirtyrate_set_state(int *state, int old_state, int new_state)
 208 {
 209     assert(new_state < DIRTY_RATE_STATUS__MAX);
 210     trace_dirtyrate_set_state(DirtyRateStatus_str(new_state));
 211     if (qatomic_cmpxchg(state, old_state, new_state) == old_state) {
 212         return 0;
 213     } else {
 214         return -1;
 215     }
 216 }
 217
 218 /* Decimal power of given time unit relative to one second */
 219 static int time_unit_to_power(TimeUnit time_unit)
 220 {
 221     switch (time_unit) {
 222     case TIME_UNIT_SECOND:
 223         return 0;
 224     case TIME_UNIT_MILLISECOND:
 225         return -3;
 226     default:
 227         assert(false); /* unreachable */
 228         return 0;
 229     }
 230 }
 231
 232 static int64_t convert_time_unit(int64_t value, TimeUnit unit_from,
 233                                  TimeUnit unit_to)
 234 {
 235     int power = time_unit_to_power(unit_from) -
 236                 time_unit_to_power(unit_to);
 237     while (power < 0) {
 238         value /= 10;
 239         power += 1;
 240     }
 241     while (power > 0) {
 242         value *= 10;
 243         power -= 1;
 244     }
 245     return value;
 246 }
 247
 248
 249 static struct DirtyRateInfo *
 250 query_dirty_rate_info(TimeUnit calc_time_unit)
 251 {
 252     int i;
 253     int64_t dirty_rate = DirtyStat.dirty_rate;
 254     struct DirtyRateInfo *info = g_new0(DirtyRateInfo, 1);
 255     DirtyRateVcpuList *head = NULL, **tail = &head;
 256
 257     info->status = CalculatingState;
 258     info->start_time = DirtyStat.start_time;
 259     info->calc_time = convert_time_unit(DirtyStat.calc_time_ms,
 260                                         TIME_UNIT_MILLISECOND,
 261                                         calc_time_unit);
 262     info->calc_time_unit = calc_time_unit;
 263     info->sample_pages = DirtyStat.sample_pages;
 264     info->mode = dirtyrate_mode;
 265
 266     if (qatomic_read(&CalculatingState) == DIRTY_RATE_STATUS_MEASURED) {
 267         info->has_dirty_rate = true;
 268         info->dirty_rate = dirty_rate;
 269
 270         if (dirtyrate_mode == DIRTY_RATE_MEASURE_MODE_DIRTY_RING) {
 271             /*
 272              * set sample_pages with 0 to indicate page sampling
 273              * isn't enabled
 274              **/
 275             info->sample_pages = 0;
 276             info->has_vcpu_dirty_rate = true;
 277             for (i = 0; i < DirtyStat.dirty_ring.nvcpu; i++) {
 278                 DirtyRateVcpu *rate = g_new0(DirtyRateVcpu, 1);
 279                 rate->id = DirtyStat.dirty_ring.rates[i].id;
 280                 rate->dirty_rate = DirtyStat.dirty_ring.rates[i].dirty_rate;
 281                 QAPI_LIST_APPEND(tail, rate);
 282             }
 283             info->vcpu_dirty_rate = head;
 284         }
 285
 286         if (dirtyrate_mode == DIRTY_RATE_MEASURE_MODE_DIRTY_BITMAP) {
 287             info->sample_pages = 0;
 288         }
 289     }
 290
 291     trace_query_dirty_rate_info(DirtyRateStatus_str(CalculatingState));
 292
 293     return info;
 294 }
 295
 296 static void init_dirtyrate_stat(int64_t start_time,
 297                                 struct DirtyRateConfig config)
 298 {
 299     DirtyStat.dirty_rate = -1;
 300     DirtyStat.start_time = start_time;
 301     DirtyStat.calc_time_ms = config.calc_time_ms;
 302     DirtyStat.sample_pages = config.sample_pages_per_gigabytes;
 303
 304     switch (config.mode) {
 305     case DIRTY_RATE_MEASURE_MODE_PAGE_SAMPLING:
 306         DirtyStat.page_sampling.total_dirty_samples = 0;
 307         DirtyStat.page_sampling.total_sample_count = 0;
 308         DirtyStat.page_sampling.total_block_mem_MB = 0;
 309         break;
 310     case DIRTY_RATE_MEASURE_MODE_DIRTY_RING:
 311         DirtyStat.dirty_ring.nvcpu = -1;
 312         DirtyStat.dirty_ring.rates = NULL;
 313         break;
 314     default:
 315         break;
 316     }
 317 }
 318
 319 static void cleanup_dirtyrate_stat(struct DirtyRateConfig config)
 320 {
 321     /* last calc-dirty-rate qmp use dirty ring mode */
 322     if (dirtyrate_mode == DIRTY_RATE_MEASURE_MODE_DIRTY_RING) {
 323         free(DirtyStat.dirty_ring.rates);
 324         DirtyStat.dirty_ring.rates = NULL;
 325     }
 326 }
 327
 328 static void update_dirtyrate_stat(struct RamblockDirtyInfo *info)
 329 {
 330     DirtyStat.page_sampling.total_dirty_samples += info->sample_dirty_count;
 331     DirtyStat.page_sampling.total_sample_count += info->sample_pages_count;
 332     /* size of total pages in MB */
 333     DirtyStat.page_sampling.total_block_mem_MB +=
 334         qemu_target_pages_to_MiB(info->ramblock_pages);
 335 }
 336
 337 static void update_dirtyrate(uint64_t msec)
 338 {
 339     uint64_t dirtyrate;
 340     uint64_t total_dirty_samples = DirtyStat.page_sampling.total_dirty_samples;
 341     uint64_t total_sample_count = DirtyStat.page_sampling.total_sample_count;
 342     uint64_t total_block_mem_MB = DirtyStat.page_sampling.total_block_mem_MB;
 343
 344     dirtyrate = total_dirty_samples * total_block_mem_MB *
 345                 1000 / (total_sample_count * msec);
 346
 347     DirtyStat.dirty_rate = dirtyrate;
 348 }
 349
 350 /*
 351  * Compute hash of a single page of size TARGET_PAGE_SIZE.
 352  */
 353 static uint32_t compute_page_hash(void *ptr)
 354 {
 355     size_t page_size = qemu_target_page_size();
 356     uint32_t i;
 357     uint64_t v1, v2, v3, v4;
 358     uint64_t res;
 359     const uint64_t *p = ptr;
 360
 361     v1 = QEMU_XXHASH_SEED + XXH_PRIME64_1 + XXH_PRIME64_2;
 362     v2 = QEMU_XXHASH_SEED + XXH_PRIME64_2;
 363     v3 = QEMU_XXHASH_SEED + 0;
 364     v4 = QEMU_XXHASH_SEED - XXH_PRIME64_1;
 365     for (i = 0; i < page_size / 8; i += 4) {
 366         v1 = XXH64_round(v1, p[i + 0]);
 367         v2 = XXH64_round(v2, p[i + 1]);
 368         v3 = XXH64_round(v3, p[i + 2]);
 369         v4 = XXH64_round(v4, p[i + 3]);
 370     }
 371     res = XXH64_mergerounds(v1, v2, v3, v4);
 372     res += page_size;
 373     res = XXH64_avalanche(res);
 374     return (uint32_t)(res & UINT32_MAX);
 375 }
 376
 377
 378 /*
 379  * get hash result for the sampled memory with length of TARGET_PAGE_SIZE
 380  * in ramblock, which starts from ramblock base address.
 381  */
 382 static uint32_t get_ramblock_vfn_hash(struct RamblockDirtyInfo *info,
 383                                       uint64_t vfn)
 384 {
 385     uint32_t hash;
 386
 387     hash = compute_page_hash(info->ramblock_addr +
 388                              vfn * qemu_target_page_size());
 389
 390     trace_get_ramblock_vfn_hash(info->idstr, vfn, hash);
 391     return hash;
 392 }
 393
 394 static bool save_ramblock_hash(struct RamblockDirtyInfo *info)
 395 {
 396     unsigned int sample_pages_count;
 397     int i;
 398     GRand *rand;
 399
 400     sample_pages_count = info->sample_pages_count;
 401
 402     /* ramblock size less than one page, return success to skip this ramblock */
 403     if (unlikely(info->ramblock_pages == 0 || sample_pages_count == 0)) {
 404         return true;
 405     }
 406
 407     info->hash_result = g_try_malloc0_n(sample_pages_count,
 408                                         sizeof(uint32_t));
 409     if (!info->hash_result) {
 410         return false;
 411     }
 412
 413     info->sample_page_vfn = g_try_malloc0_n(sample_pages_count,
 414                                             sizeof(uint64_t));
 415     if (!info->sample_page_vfn) {
 416         g_free(info->hash_result);
 417         return false;
 418     }
 419
 420     rand  = g_rand_new();
 421     for (i = 0; i < sample_pages_count; i++) {
 422         info->sample_page_vfn[i] = g_rand_int_range(rand, 0,
 423                                                     info->ramblock_pages - 1);
 424         info->hash_result[i] = get_ramblock_vfn_hash(info,
 425                                                      info->sample_page_vfn[i]);
 426     }
 427     g_rand_free(rand);
 428
 429     return true;
 430 }
 431
 432 static void get_ramblock_dirty_info(RAMBlock *block,
 433                                     struct RamblockDirtyInfo *info,
 434                                     struct DirtyRateConfig *config)
 435 {
 436     uint64_t sample_pages_per_gigabytes = config->sample_pages_per_gigabytes;
 437
 438     /* Right shift 30 bits to calc ramblock size in GB */
 439     info->sample_pages_count = (qemu_ram_get_used_length(block) *
 440                                 sample_pages_per_gigabytes) >> 30;
 441     /* Right shift TARGET_PAGE_BITS to calc page count */
 442     info->ramblock_pages = qemu_ram_get_used_length(block) >>
 443                            qemu_target_page_bits();
 444     info->ramblock_addr = qemu_ram_get_host_addr(block);
 445     strcpy(info->idstr, qemu_ram_get_idstr(block));
 446 }
 447
 448 static void free_ramblock_dirty_info(struct RamblockDirtyInfo *infos, int count)
 449 {
 450     int i;
 451
 452     if (!infos) {
 453         return;
 454     }
 455
 456     for (i = 0; i < count; i++) {
 457         g_free(infos[i].sample_page_vfn);
 458         g_free(infos[i].hash_result);
 459     }
 460     g_free(infos);
 461 }
 462
 463 static bool skip_sample_ramblock(RAMBlock *block)
 464 {
 465     /*
 466      * Sample only blocks larger than MIN_RAMBLOCK_SIZE.
 467      */
 468     if (qemu_ram_get_used_length(block) < (MIN_RAMBLOCK_SIZE << 10)) {
 469         trace_skip_sample_ramblock(block->idstr,
 470                                    qemu_ram_get_used_length(block));
 471         return true;
 472     }
 473
 474     return false;
 475 }
 476
 477 static bool record_ramblock_hash_info(struct RamblockDirtyInfo **block_dinfo,
 478                                       struct DirtyRateConfig config,
 479                                       int *block_count)
 480 {
 481     struct RamblockDirtyInfo *info = NULL;
 482     struct RamblockDirtyInfo *dinfo = NULL;
 483     RAMBlock *block = NULL;
 484     int total_count = 0;
 485     int index = 0;
 486     bool ret = false;
 487
 488     RAMBLOCK_FOREACH_MIGRATABLE(block) {
 489         if (skip_sample_ramblock(block)) {
 490             continue;
 491         }
 492         total_count++;
 493     }
 494
 495     dinfo = g_try_malloc0_n(total_count, sizeof(struct RamblockDirtyInfo));
 496     if (dinfo == NULL) {
 497         goto out;
 498     }
 499
 500     RAMBLOCK_FOREACH_MIGRATABLE(block) {
 501         if (skip_sample_ramblock(block)) {
 502             continue;
 503         }
 504         if (index >= total_count) {
 505             break;
 506         }
 507         info = &dinfo[index];
 508         get_ramblock_dirty_info(block, info, &config);
 509         if (!save_ramblock_hash(info)) {
 510             goto out;
 511         }
 512         index++;
 513     }
 514     ret = true;
 515
 516 out:
 517     *block_count = index;
 518     *block_dinfo = dinfo;
 519     return ret;
 520 }
 521
 522 static void calc_page_dirty_rate(struct RamblockDirtyInfo *info)
 523 {
 524     uint32_t hash;
 525     int i;
 526
 527     for (i = 0; i < info->sample_pages_count; i++) {
 528         hash = get_ramblock_vfn_hash(info, info->sample_page_vfn[i]);
 529         if (hash != info->hash_result[i]) {
 530             trace_calc_page_dirty_rate(info->idstr, hash, info->hash_result[i]);
 531             info->sample_dirty_count++;
 532         }
 533     }
 534 }
 535
 536 static struct RamblockDirtyInfo *
 537 find_block_matched(RAMBlock *block, int count,
 538                   struct RamblockDirtyInfo *infos)
 539 {
 540     int i;
 541
 542     for (i = 0; i < count; i++) {
 543         if (!strcmp(infos[i].idstr, qemu_ram_get_idstr(block))) {
 544             break;
 545         }
 546     }
 547
 548     if (i == count) {
 549         return NULL;
 550     }
 551
 552     if (infos[i].ramblock_addr != qemu_ram_get_host_addr(block) ||
 553         infos[i].ramblock_pages !=
 554             (qemu_ram_get_used_length(block) >> qemu_target_page_bits())) {
 555         trace_find_page_matched(block->idstr);
 556         return NULL;
 557     }
 558
 559     return &infos[i];
 560 }
 561
 562 static bool compare_page_hash_info(struct RamblockDirtyInfo *info,
 563                                   int block_count)
 564 {
 565     struct RamblockDirtyInfo *block_dinfo = NULL;
 566     RAMBlock *block = NULL;
 567
 568     RAMBLOCK_FOREACH_MIGRATABLE(block) {
 569         if (skip_sample_ramblock(block)) {
 570             continue;
 571         }
 572         block_dinfo = find_block_matched(block, block_count, info);
 573         if (block_dinfo == NULL) {
 574             continue;
 575         }
 576         calc_page_dirty_rate(block_dinfo);
 577         update_dirtyrate_stat(block_dinfo);
 578     }
 579
 580     if (DirtyStat.page_sampling.total_sample_count == 0) {
 581         return false;
 582     }
 583
 584     return true;
 585 }
 586
 587 static inline void record_dirtypages_bitmap(DirtyPageRecord *dirty_pages,
 588                                             bool start)
 589 {
 590     if (start) {
 591         dirty_pages->start_pages = total_dirty_pages;
 592     } else {
 593         dirty_pages->end_pages = total_dirty_pages;
 594     }
 595 }
 596
 597 static inline void dirtyrate_manual_reset_protect(void)
 598 {
 599     RAMBlock *block = NULL;
 600
 601     WITH_RCU_READ_LOCK_GUARD() {
 602         RAMBLOCK_FOREACH_MIGRATABLE(block) {
 603             memory_region_clear_dirty_bitmap(block->mr, 0,
 604                                              block->used_length);
 605         }
 606     }
 607 }
 608
 609 static void calculate_dirtyrate_dirty_bitmap(struct DirtyRateConfig config)
 610 {
 611     int64_t start_time;
 612     DirtyPageRecord dirty_pages;
 613
 614     qemu_mutex_lock_iothread();
 615     memory_global_dirty_log_start(GLOBAL_DIRTY_DIRTY_RATE);
 616
 617     /*
 618      * 1'round of log sync may return all 1 bits with
 619      * KVM_DIRTY_LOG_INITIALLY_SET enable
 620      * skip it unconditionally and start dirty tracking
 621      * from 2'round of log sync
 622      */
 623     memory_global_dirty_log_sync(false);
 624
 625     /*
 626      * reset page protect manually and unconditionally.
 627      * this make sure kvm dirty log be cleared if
 628      * KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE cap is enabled.
 629      */
 630     dirtyrate_manual_reset_protect();
 631     qemu_mutex_unlock_iothread();
 632
 633     record_dirtypages_bitmap(&dirty_pages, true);
 634
 635     start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
 636     DirtyStat.start_time = start_time / 1000;
 637
 638     DirtyStat.calc_time_ms = dirty_stat_wait(config.calc_time_ms, start_time);
 639
 640     /*
 641      * do two things.
 642      * 1. fetch dirty bitmap from kvm
 643      * 2. stop dirty tracking
 644      */
 645     global_dirty_log_sync(GLOBAL_DIRTY_DIRTY_RATE, true);
 646
 647     record_dirtypages_bitmap(&dirty_pages, false);
 648
 649     DirtyStat.dirty_rate = do_calculate_dirtyrate(dirty_pages,
 650                                                   DirtyStat.calc_time_ms);
 651 }
 652
 653 static void calculate_dirtyrate_dirty_ring(struct DirtyRateConfig config)
 654 {
 655     uint64_t dirtyrate = 0;
 656     uint64_t dirtyrate_sum = 0;
 657     int i = 0;
 658
 659     /* start log sync */
 660     global_dirty_log_change(GLOBAL_DIRTY_DIRTY_RATE, true);
 661
 662     DirtyStat.start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) / 1000;
 663
 664     /* calculate vcpu dirtyrate */
 665     DirtyStat.calc_time_ms = vcpu_calculate_dirtyrate(config.calc_time_ms,
 666                                                       &DirtyStat.dirty_ring,
 667                                                       GLOBAL_DIRTY_DIRTY_RATE,
 668                                                       true);
 669
 670     /* calculate vm dirtyrate */
 671     for (i = 0; i < DirtyStat.dirty_ring.nvcpu; i++) {
 672         dirtyrate = DirtyStat.dirty_ring.rates[i].dirty_rate;
 673         DirtyStat.dirty_ring.rates[i].dirty_rate = dirtyrate;
 674         dirtyrate_sum += dirtyrate;
 675     }
 676
 677     DirtyStat.dirty_rate = dirtyrate_sum;
 678 }
 679
 680 static void calculate_dirtyrate_sample_vm(struct DirtyRateConfig config)
 681 {
 682     struct RamblockDirtyInfo *block_dinfo = NULL;
 683     int block_count = 0;
 684     int64_t initial_time;
 685
 686     rcu_read_lock();
 687     initial_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
 688     if (!record_ramblock_hash_info(&block_dinfo, config, &block_count)) {
 689         goto out;
 690     }
 691     rcu_read_unlock();
 692
 693     DirtyStat.calc_time_ms = dirty_stat_wait(config.calc_time_ms,
 694                                              initial_time);
 695     DirtyStat.start_time = initial_time / 1000;
 696
 697     rcu_read_lock();
 698     if (!compare_page_hash_info(block_dinfo, block_count)) {
 699         goto out;
 700     }
 701
 702     update_dirtyrate(DirtyStat.calc_time_ms);
 703
 704 out:
 705     rcu_read_unlock();
 706     free_ramblock_dirty_info(block_dinfo, block_count);
 707 }
 708
 709 static void calculate_dirtyrate(struct DirtyRateConfig config)
 710 {
 711     if (config.mode == DIRTY_RATE_MEASURE_MODE_DIRTY_BITMAP) {
 712         calculate_dirtyrate_dirty_bitmap(config);
 713     } else if (config.mode == DIRTY_RATE_MEASURE_MODE_DIRTY_RING) {
 714         calculate_dirtyrate_dirty_ring(config);
 715     } else {
 716         calculate_dirtyrate_sample_vm(config);
 717     }
 718
 719     trace_dirtyrate_calculate(DirtyStat.dirty_rate);
 720 }
 721
 722 void *get_dirtyrate_thread(void *arg)
 723 {
 724     struct DirtyRateConfig config = *(struct DirtyRateConfig *)arg;
 725     int ret;
 726     rcu_register_thread();
 727
 728     ret = dirtyrate_set_state(&CalculatingState, DIRTY_RATE_STATUS_UNSTARTED,
 729                               DIRTY_RATE_STATUS_MEASURING);
 730     if (ret == -1) {
 731         error_report("change dirtyrate state failed.");
 732         return NULL;
 733     }
 734
 735     calculate_dirtyrate(config);
 736
 737     ret = dirtyrate_set_state(&CalculatingState, DIRTY_RATE_STATUS_MEASURING,
 738                               DIRTY_RATE_STATUS_MEASURED);
 739     if (ret == -1) {
 740         error_report("change dirtyrate state failed.");
 741     }
 742
 743     rcu_unregister_thread();
 744     return NULL;
 745 }
 746
 747 void qmp_calc_dirty_rate(int64_t calc_time,
 748                          bool has_calc_time_unit,
 749                          TimeUnit calc_time_unit,
 750                          bool has_sample_pages,
 751                          int64_t sample_pages,
 752                          bool has_mode,
 753                          DirtyRateMeasureMode mode,
 754                          Error **errp)
 755 {
 756     static struct DirtyRateConfig config;
 757     QemuThread thread;
 758     int ret;
 759     int64_t start_time;
 760
 761     /*
 762      * If the dirty rate is already being measured, don't attempt to start.
 763      */
 764     if (qatomic_read(&CalculatingState) == DIRTY_RATE_STATUS_MEASURING) {
 765         error_setg(errp, "the dirty rate is already being measured.");
 766         return;
 767     }
 768
 769     int64_t calc_time_ms = convert_time_unit(
 770         calc_time,
 771         has_calc_time_unit ? calc_time_unit : TIME_UNIT_SECOND,
 772         TIME_UNIT_MILLISECOND
 773     );
 774
 775     if (!is_calc_time_valid(calc_time_ms)) {
 776         error_setg(errp, "Calculation time is out of range [%dms, %dms].",
 777                          MIN_CALC_TIME_MS, MAX_CALC_TIME_MS);
 778         return;
 779     }
 780
 781     if (!has_mode) {
 782         mode =  DIRTY_RATE_MEASURE_MODE_PAGE_SAMPLING;
 783     }
 784
 785     if (has_sample_pages && mode != DIRTY_RATE_MEASURE_MODE_PAGE_SAMPLING) {
 786         error_setg(errp, "sample-pages is used only in page-sampling mode");
 787         return;
 788     }
 789
 790     if (has_sample_pages) {
 791         if (!is_sample_pages_valid(sample_pages)) {
 792             error_setg(errp, "sample-pages is out of range[%d, %d].",
 793                             MIN_SAMPLE_PAGE_COUNT,
 794                             MAX_SAMPLE_PAGE_COUNT);
 795             return;
 796         }
 797     } else {
 798         sample_pages = DIRTYRATE_DEFAULT_SAMPLE_PAGES;
 799     }
 800
 801     /*
 802      * dirty ring mode only works when kvm dirty ring is enabled.
 803      * on the contrary, dirty bitmap mode is not.
 804      */
 805     if (((mode == DIRTY_RATE_MEASURE_MODE_DIRTY_RING) &&
 806         !kvm_dirty_ring_enabled()) ||
 807         ((mode == DIRTY_RATE_MEASURE_MODE_DIRTY_BITMAP) &&
 808          kvm_dirty_ring_enabled())) {
 809         error_setg(errp, "mode %s is not enabled, use other method instead.",
 810                          DirtyRateMeasureMode_str(mode));
 811          return;
 812     }
 813
 814     /*
 815      * Init calculation state as unstarted.
 816      */
 817     ret = dirtyrate_set_state(&CalculatingState, CalculatingState,
 818                               DIRTY_RATE_STATUS_UNSTARTED);
 819     if (ret == -1) {
 820         error_setg(errp, "init dirty rate calculation state failed.");
 821         return;
 822     }
 823
 824     config.calc_time_ms = calc_time_ms;
 825     config.sample_pages_per_gigabytes = sample_pages;
 826     config.mode = mode;
 827
 828     cleanup_dirtyrate_stat(config);
 829
 830     /*
 831      * update dirty rate mode so that we can figure out what mode has
 832      * been used in last calculation
 833      **/
 834     dirtyrate_mode = mode;
 835
 836     start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) / 1000;
 837     init_dirtyrate_stat(start_time, config);
 838
 839     qemu_thread_create(&thread, "get_dirtyrate", get_dirtyrate_thread,
 840                        (void *)&config, QEMU_THREAD_DETACHED);
 841 }
 842
 843
 844 struct DirtyRateInfo *qmp_query_dirty_rate(bool has_calc_time_unit,
 845                                            TimeUnit calc_time_unit,
 846                                            Error **errp)
 847 {
 848     return query_dirty_rate_info(
 849         has_calc_time_unit ? calc_time_unit : TIME_UNIT_SECOND);
 850 }
 851
 852 void hmp_info_dirty_rate(Monitor *mon, const QDict *qdict)
 853 {
 854     DirtyRateInfo *info = query_dirty_rate_info(TIME_UNIT_SECOND);
 855
 856     monitor_printf(mon, "Status: %s\n",
 857                    DirtyRateStatus_str(info->status));
 858     monitor_printf(mon, "Start Time: %"PRIi64" (ms)\n",
 859                    info->start_time);
 860     if (info->mode == DIRTY_RATE_MEASURE_MODE_PAGE_SAMPLING) {
 861         monitor_printf(mon, "Sample Pages: %"PRIu64" (per GB)\n",
 862                        info->sample_pages);
 863     }
 864     monitor_printf(mon, "Period: %"PRIi64" (sec)\n",
 865                    info->calc_time);
 866     monitor_printf(mon, "Mode: %s\n",
 867                    DirtyRateMeasureMode_str(info->mode));
 868     monitor_printf(mon, "Dirty rate: ");
 869     if (info->has_dirty_rate) {
 870         monitor_printf(mon, "%"PRIi64" (MB/s)\n", info->dirty_rate);
 871         if (info->has_vcpu_dirty_rate) {
 872             DirtyRateVcpuList *rate, *head = info->vcpu_dirty_rate;
 873             for (rate = head; rate != NULL; rate = rate->next) {
 874                 monitor_printf(mon, "vcpu[%"PRIi64"], Dirty rate: %"PRIi64
 875                                " (MB/s)\n", rate->value->id,
 876                                rate->value->dirty_rate);
 877             }
 878         }
 879     } else {
 880         monitor_printf(mon, "(not ready)\n");
 881     }
 882
 883     qapi_free_DirtyRateVcpuList(info->vcpu_dirty_rate);
 884     g_free(info);
 885 }
 886
 887 void hmp_calc_dirty_rate(Monitor *mon, const QDict *qdict)
 888 {
 889     int64_t sec = qdict_get_try_int(qdict, "second", 0);
 890     int64_t sample_pages = qdict_get_try_int(qdict, "sample_pages_per_GB", -1);
 891     bool has_sample_pages = (sample_pages != -1);
 892     bool dirty_ring = qdict_get_try_bool(qdict, "dirty_ring", false);
 893     bool dirty_bitmap = qdict_get_try_bool(qdict, "dirty_bitmap", false);
 894     DirtyRateMeasureMode mode = DIRTY_RATE_MEASURE_MODE_PAGE_SAMPLING;
 895     Error *err = NULL;
 896
 897     if (!sec) {
 898         monitor_printf(mon, "Incorrect period length specified!\n");
 899         return;
 900     }
 901
 902     if (dirty_ring && dirty_bitmap) {
 903         monitor_printf(mon, "Either dirty ring or dirty bitmap "
 904                        "can be specified!\n");
 905         return;
 906     }
 907
 908     if (dirty_bitmap) {
 909         mode = DIRTY_RATE_MEASURE_MODE_DIRTY_BITMAP;
 910     } else if (dirty_ring) {
 911         mode = DIRTY_RATE_MEASURE_MODE_DIRTY_RING;
 912     }
 913
 914     qmp_calc_dirty_rate(sec, /* calc-time */
 915                         false, TIME_UNIT_SECOND, /* calc-time-unit */
 916                         has_sample_pages, sample_pages,
 917                         true, mode,
 918                         &err);
 919     if (err) {
 920         hmp_handle_error(mon, err);
 921         return;
 922     }
 923
 924     monitor_printf(mon, "Starting dirty rate measurement with period %"PRIi64
 925                    " seconds\n", sec);
 926     monitor_printf(mon, "[Please use 'info dirty_rate' to check results]\n");
 927 }