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