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_sample_period_valid(int64_t sec)
 193 {
 194     if (sec < MIN_FETCH_DIRTYRATE_TIME_SEC ||
 195         sec > MAX_FETCH_DIRTYRATE_TIME_SEC) {
 196         return false;
 197     }
 198
 199     return true;
 200 }
 201
 202 static bool is_sample_pages_valid(int64_t pages)
 203 {
 204     return pages >= MIN_SAMPLE_PAGE_COUNT &&
 205            pages <= MAX_SAMPLE_PAGE_COUNT;
 206 }
 207
 208 static int dirtyrate_set_state(int *state, int old_state, int new_state)
 209 {
 210     assert(new_state < DIRTY_RATE_STATUS__MAX);
 211     trace_dirtyrate_set_state(DirtyRateStatus_str(new_state));
 212     if (qatomic_cmpxchg(state, old_state, new_state) == old_state) {
 213         return 0;
 214     } else {
 215         return -1;
 216     }
 217 }
 218
 219 static struct DirtyRateInfo *query_dirty_rate_info(void)
 220 {
 221     int i;
 222     int64_t dirty_rate = DirtyStat.dirty_rate;
 223     struct DirtyRateInfo *info = g_new0(DirtyRateInfo, 1);
 224     DirtyRateVcpuList *head = NULL, **tail = &head;
 225
 226     info->status = CalculatingState;
 227     info->start_time = DirtyStat.start_time;
 228     info->calc_time = DirtyStat.calc_time;
 229     info->sample_pages = DirtyStat.sample_pages;
 230     info->mode = dirtyrate_mode;
 231
 232     if (qatomic_read(&CalculatingState) == DIRTY_RATE_STATUS_MEASURED) {
 233         info->has_dirty_rate = true;
 234         info->dirty_rate = dirty_rate;
 235
 236         if (dirtyrate_mode == DIRTY_RATE_MEASURE_MODE_DIRTY_RING) {
 237             /*
 238              * set sample_pages with 0 to indicate page sampling
 239              * isn't enabled
 240              **/
 241             info->sample_pages = 0;
 242             info->has_vcpu_dirty_rate = true;
 243             for (i = 0; i < DirtyStat.dirty_ring.nvcpu; i++) {
 244                 DirtyRateVcpu *rate = g_new0(DirtyRateVcpu, 1);
 245                 rate->id = DirtyStat.dirty_ring.rates[i].id;
 246                 rate->dirty_rate = DirtyStat.dirty_ring.rates[i].dirty_rate;
 247                 QAPI_LIST_APPEND(tail, rate);
 248             }
 249             info->vcpu_dirty_rate = head;
 250         }
 251
 252         if (dirtyrate_mode == DIRTY_RATE_MEASURE_MODE_DIRTY_BITMAP) {
 253             info->sample_pages = 0;
 254         }
 255     }
 256
 257     trace_query_dirty_rate_info(DirtyRateStatus_str(CalculatingState));
 258
 259     return info;
 260 }
 261
 262 static void init_dirtyrate_stat(int64_t start_time,
 263                                 struct DirtyRateConfig config)
 264 {
 265     DirtyStat.dirty_rate = -1;
 266     DirtyStat.start_time = start_time;
 267     DirtyStat.calc_time = config.sample_period_seconds;
 268     DirtyStat.sample_pages = config.sample_pages_per_gigabytes;
 269
 270     switch (config.mode) {
 271     case DIRTY_RATE_MEASURE_MODE_PAGE_SAMPLING:
 272         DirtyStat.page_sampling.total_dirty_samples = 0;
 273         DirtyStat.page_sampling.total_sample_count = 0;
 274         DirtyStat.page_sampling.total_block_mem_MB = 0;
 275         break;
 276     case DIRTY_RATE_MEASURE_MODE_DIRTY_RING:
 277         DirtyStat.dirty_ring.nvcpu = -1;
 278         DirtyStat.dirty_ring.rates = NULL;
 279         break;
 280     default:
 281         break;
 282     }
 283 }
 284
 285 static void cleanup_dirtyrate_stat(struct DirtyRateConfig config)
 286 {
 287     /* last calc-dirty-rate qmp use dirty ring mode */
 288     if (dirtyrate_mode == DIRTY_RATE_MEASURE_MODE_DIRTY_RING) {
 289         free(DirtyStat.dirty_ring.rates);
 290         DirtyStat.dirty_ring.rates = NULL;
 291     }
 292 }
 293
 294 static void update_dirtyrate_stat(struct RamblockDirtyInfo *info)
 295 {
 296     DirtyStat.page_sampling.total_dirty_samples += info->sample_dirty_count;
 297     DirtyStat.page_sampling.total_sample_count += info->sample_pages_count;
 298     /* size of total pages in MB */
 299     DirtyStat.page_sampling.total_block_mem_MB +=
 300         qemu_target_pages_to_MiB(info->ramblock_pages);
 301 }
 302
 303 static void update_dirtyrate(uint64_t msec)
 304 {
 305     uint64_t dirtyrate;
 306     uint64_t total_dirty_samples = DirtyStat.page_sampling.total_dirty_samples;
 307     uint64_t total_sample_count = DirtyStat.page_sampling.total_sample_count;
 308     uint64_t total_block_mem_MB = DirtyStat.page_sampling.total_block_mem_MB;
 309
 310     dirtyrate = total_dirty_samples * total_block_mem_MB *
 311                 1000 / (total_sample_count * msec);
 312
 313     DirtyStat.dirty_rate = dirtyrate;
 314 }
 315
 316 /*
 317  * Compute hash of a single page of size TARGET_PAGE_SIZE.
 318  */
 319 static uint32_t compute_page_hash(void *ptr)
 320 {
 321     size_t page_size = qemu_target_page_size();
 322     uint32_t i;
 323     uint64_t v1, v2, v3, v4;
 324     uint64_t res;
 325     const uint64_t *p = ptr;
 326
 327     v1 = QEMU_XXHASH_SEED + XXH_PRIME64_1 + XXH_PRIME64_2;
 328     v2 = QEMU_XXHASH_SEED + XXH_PRIME64_2;
 329     v3 = QEMU_XXHASH_SEED + 0;
 330     v4 = QEMU_XXHASH_SEED - XXH_PRIME64_1;
 331     for (i = 0; i < page_size / 8; i += 4) {
 332         v1 = XXH64_round(v1, p[i + 0]);
 333         v2 = XXH64_round(v2, p[i + 1]);
 334         v3 = XXH64_round(v3, p[i + 2]);
 335         v4 = XXH64_round(v4, p[i + 3]);
 336     }
 337     res = XXH64_mergerounds(v1, v2, v3, v4);
 338     res += page_size;
 339     res = XXH64_avalanche(res);
 340     return (uint32_t)(res & UINT32_MAX);
 341 }
 342
 343
 344 /*
 345  * get hash result for the sampled memory with length of TARGET_PAGE_SIZE
 346  * in ramblock, which starts from ramblock base address.
 347  */
 348 static uint32_t get_ramblock_vfn_hash(struct RamblockDirtyInfo *info,
 349                                       uint64_t vfn)
 350 {
 351     uint32_t hash;
 352
 353     hash = compute_page_hash(info->ramblock_addr +
 354                              vfn * qemu_target_page_size());
 355
 356     trace_get_ramblock_vfn_hash(info->idstr, vfn, hash);
 357     return hash;
 358 }
 359
 360 static bool save_ramblock_hash(struct RamblockDirtyInfo *info)
 361 {
 362     unsigned int sample_pages_count;
 363     int i;
 364     GRand *rand;
 365
 366     sample_pages_count = info->sample_pages_count;
 367
 368     /* ramblock size less than one page, return success to skip this ramblock */
 369     if (unlikely(info->ramblock_pages == 0 || sample_pages_count == 0)) {
 370         return true;
 371     }
 372
 373     info->hash_result = g_try_malloc0_n(sample_pages_count,
 374                                         sizeof(uint32_t));
 375     if (!info->hash_result) {
 376         return false;
 377     }
 378
 379     info->sample_page_vfn = g_try_malloc0_n(sample_pages_count,
 380                                             sizeof(uint64_t));
 381     if (!info->sample_page_vfn) {
 382         g_free(info->hash_result);
 383         return false;
 384     }
 385
 386     rand  = g_rand_new();
 387     for (i = 0; i < sample_pages_count; i++) {
 388         info->sample_page_vfn[i] = g_rand_int_range(rand, 0,
 389                                                     info->ramblock_pages - 1);
 390         info->hash_result[i] = get_ramblock_vfn_hash(info,
 391                                                      info->sample_page_vfn[i]);
 392     }
 393     g_rand_free(rand);
 394
 395     return true;
 396 }
 397
 398 static void get_ramblock_dirty_info(RAMBlock *block,
 399                                     struct RamblockDirtyInfo *info,
 400                                     struct DirtyRateConfig *config)
 401 {
 402     uint64_t sample_pages_per_gigabytes = config->sample_pages_per_gigabytes;
 403
 404     /* Right shift 30 bits to calc ramblock size in GB */
 405     info->sample_pages_count = (qemu_ram_get_used_length(block) *
 406                                 sample_pages_per_gigabytes) >> 30;
 407     /* Right shift TARGET_PAGE_BITS to calc page count */
 408     info->ramblock_pages = qemu_ram_get_used_length(block) >>
 409                            qemu_target_page_bits();
 410     info->ramblock_addr = qemu_ram_get_host_addr(block);
 411     strcpy(info->idstr, qemu_ram_get_idstr(block));
 412 }
 413
 414 static void free_ramblock_dirty_info(struct RamblockDirtyInfo *infos, int count)
 415 {
 416     int i;
 417
 418     if (!infos) {
 419         return;
 420     }
 421
 422     for (i = 0; i < count; i++) {
 423         g_free(infos[i].sample_page_vfn);
 424         g_free(infos[i].hash_result);
 425     }
 426     g_free(infos);
 427 }
 428
 429 static bool skip_sample_ramblock(RAMBlock *block)
 430 {
 431     /*
 432      * Sample only blocks larger than MIN_RAMBLOCK_SIZE.
 433      */
 434     if (qemu_ram_get_used_length(block) < (MIN_RAMBLOCK_SIZE << 10)) {
 435         trace_skip_sample_ramblock(block->idstr,
 436                                    qemu_ram_get_used_length(block));
 437         return true;
 438     }
 439
 440     return false;
 441 }
 442
 443 static bool record_ramblock_hash_info(struct RamblockDirtyInfo **block_dinfo,
 444                                       struct DirtyRateConfig config,
 445                                       int *block_count)
 446 {
 447     struct RamblockDirtyInfo *info = NULL;
 448     struct RamblockDirtyInfo *dinfo = NULL;
 449     RAMBlock *block = NULL;
 450     int total_count = 0;
 451     int index = 0;
 452     bool ret = false;
 453
 454     RAMBLOCK_FOREACH_MIGRATABLE(block) {
 455         if (skip_sample_ramblock(block)) {
 456             continue;
 457         }
 458         total_count++;
 459     }
 460
 461     dinfo = g_try_malloc0_n(total_count, sizeof(struct RamblockDirtyInfo));
 462     if (dinfo == NULL) {
 463         goto out;
 464     }
 465
 466     RAMBLOCK_FOREACH_MIGRATABLE(block) {
 467         if (skip_sample_ramblock(block)) {
 468             continue;
 469         }
 470         if (index >= total_count) {
 471             break;
 472         }
 473         info = &dinfo[index];
 474         get_ramblock_dirty_info(block, info, &config);
 475         if (!save_ramblock_hash(info)) {
 476             goto out;
 477         }
 478         index++;
 479     }
 480     ret = true;
 481
 482 out:
 483     *block_count = index;
 484     *block_dinfo = dinfo;
 485     return ret;
 486 }
 487
 488 static void calc_page_dirty_rate(struct RamblockDirtyInfo *info)
 489 {
 490     uint32_t hash;
 491     int i;
 492
 493     for (i = 0; i < info->sample_pages_count; i++) {
 494         hash = get_ramblock_vfn_hash(info, info->sample_page_vfn[i]);
 495         if (hash != info->hash_result[i]) {
 496             trace_calc_page_dirty_rate(info->idstr, hash, info->hash_result[i]);
 497             info->sample_dirty_count++;
 498         }
 499     }
 500 }
 501
 502 static struct RamblockDirtyInfo *
 503 find_block_matched(RAMBlock *block, int count,
 504                   struct RamblockDirtyInfo *infos)
 505 {
 506     int i;
 507
 508     for (i = 0; i < count; i++) {
 509         if (!strcmp(infos[i].idstr, qemu_ram_get_idstr(block))) {
 510             break;
 511         }
 512     }
 513
 514     if (i == count) {
 515         return NULL;
 516     }
 517
 518     if (infos[i].ramblock_addr != qemu_ram_get_host_addr(block) ||
 519         infos[i].ramblock_pages !=
 520             (qemu_ram_get_used_length(block) >> qemu_target_page_bits())) {
 521         trace_find_page_matched(block->idstr);
 522         return NULL;
 523     }
 524
 525     return &infos[i];
 526 }
 527
 528 static bool compare_page_hash_info(struct RamblockDirtyInfo *info,
 529                                   int block_count)
 530 {
 531     struct RamblockDirtyInfo *block_dinfo = NULL;
 532     RAMBlock *block = NULL;
 533
 534     RAMBLOCK_FOREACH_MIGRATABLE(block) {
 535         if (skip_sample_ramblock(block)) {
 536             continue;
 537         }
 538         block_dinfo = find_block_matched(block, block_count, info);
 539         if (block_dinfo == NULL) {
 540             continue;
 541         }
 542         calc_page_dirty_rate(block_dinfo);
 543         update_dirtyrate_stat(block_dinfo);
 544     }
 545
 546     if (DirtyStat.page_sampling.total_sample_count == 0) {
 547         return false;
 548     }
 549
 550     return true;
 551 }
 552
 553 static inline void record_dirtypages_bitmap(DirtyPageRecord *dirty_pages,
 554                                             bool start)
 555 {
 556     if (start) {
 557         dirty_pages->start_pages = total_dirty_pages;
 558     } else {
 559         dirty_pages->end_pages = total_dirty_pages;
 560     }
 561 }
 562
 563 static inline void dirtyrate_manual_reset_protect(void)
 564 {
 565     RAMBlock *block = NULL;
 566
 567     WITH_RCU_READ_LOCK_GUARD() {
 568         RAMBLOCK_FOREACH_MIGRATABLE(block) {
 569             memory_region_clear_dirty_bitmap(block->mr, 0,
 570                                              block->used_length);
 571         }
 572     }
 573 }
 574
 575 static void calculate_dirtyrate_dirty_bitmap(struct DirtyRateConfig config)
 576 {
 577     int64_t msec = 0;
 578     int64_t start_time;
 579     DirtyPageRecord dirty_pages;
 580
 581     qemu_mutex_lock_iothread();
 582     memory_global_dirty_log_start(GLOBAL_DIRTY_DIRTY_RATE);
 583
 584     /*
 585      * 1'round of log sync may return all 1 bits with
 586      * KVM_DIRTY_LOG_INITIALLY_SET enable
 587      * skip it unconditionally and start dirty tracking
 588      * from 2'round of log sync
 589      */
 590     memory_global_dirty_log_sync(false);
 591
 592     /*
 593      * reset page protect manually and unconditionally.
 594      * this make sure kvm dirty log be cleared if
 595      * KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE cap is enabled.
 596      */
 597     dirtyrate_manual_reset_protect();
 598     qemu_mutex_unlock_iothread();
 599
 600     record_dirtypages_bitmap(&dirty_pages, true);
 601
 602     start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
 603     DirtyStat.start_time = start_time / 1000;
 604
 605     msec = config.sample_period_seconds * 1000;
 606     msec = dirty_stat_wait(msec, start_time);
 607     DirtyStat.calc_time = msec / 1000;
 608
 609     /*
 610      * do two things.
 611      * 1. fetch dirty bitmap from kvm
 612      * 2. stop dirty tracking
 613      */
 614     global_dirty_log_sync(GLOBAL_DIRTY_DIRTY_RATE, true);
 615
 616     record_dirtypages_bitmap(&dirty_pages, false);
 617
 618     DirtyStat.dirty_rate = do_calculate_dirtyrate(dirty_pages, msec);
 619 }
 620
 621 static void calculate_dirtyrate_dirty_ring(struct DirtyRateConfig config)
 622 {
 623     int64_t duration;
 624     uint64_t dirtyrate = 0;
 625     uint64_t dirtyrate_sum = 0;
 626     int i = 0;
 627
 628     /* start log sync */
 629     global_dirty_log_change(GLOBAL_DIRTY_DIRTY_RATE, true);
 630
 631     DirtyStat.start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) / 1000;
 632
 633     /* calculate vcpu dirtyrate */
 634     duration = vcpu_calculate_dirtyrate(config.sample_period_seconds * 1000,
 635                                         &DirtyStat.dirty_ring,
 636                                         GLOBAL_DIRTY_DIRTY_RATE,
 637                                         true);
 638
 639     DirtyStat.calc_time = duration / 1000;
 640
 641     /* calculate vm dirtyrate */
 642     for (i = 0; i < DirtyStat.dirty_ring.nvcpu; i++) {
 643         dirtyrate = DirtyStat.dirty_ring.rates[i].dirty_rate;
 644         DirtyStat.dirty_ring.rates[i].dirty_rate = dirtyrate;
 645         dirtyrate_sum += dirtyrate;
 646     }
 647
 648     DirtyStat.dirty_rate = dirtyrate_sum;
 649 }
 650
 651 static void calculate_dirtyrate_sample_vm(struct DirtyRateConfig config)
 652 {
 653     struct RamblockDirtyInfo *block_dinfo = NULL;
 654     int block_count = 0;
 655     int64_t msec = 0;
 656     int64_t initial_time;
 657
 658     rcu_read_lock();
 659     initial_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
 660     if (!record_ramblock_hash_info(&block_dinfo, config, &block_count)) {
 661         goto out;
 662     }
 663     rcu_read_unlock();
 664
 665     msec = config.sample_period_seconds * 1000;
 666     msec = dirty_stat_wait(msec, initial_time);
 667     DirtyStat.start_time = initial_time / 1000;
 668     DirtyStat.calc_time = msec / 1000;
 669
 670     rcu_read_lock();
 671     if (!compare_page_hash_info(block_dinfo, block_count)) {
 672         goto out;
 673     }
 674
 675     update_dirtyrate(msec);
 676
 677 out:
 678     rcu_read_unlock();
 679     free_ramblock_dirty_info(block_dinfo, block_count);
 680 }
 681
 682 static void calculate_dirtyrate(struct DirtyRateConfig config)
 683 {
 684     if (config.mode == DIRTY_RATE_MEASURE_MODE_DIRTY_BITMAP) {
 685         calculate_dirtyrate_dirty_bitmap(config);
 686     } else if (config.mode == DIRTY_RATE_MEASURE_MODE_DIRTY_RING) {
 687         calculate_dirtyrate_dirty_ring(config);
 688     } else {
 689         calculate_dirtyrate_sample_vm(config);
 690     }
 691
 692     trace_dirtyrate_calculate(DirtyStat.dirty_rate);
 693 }
 694
 695 void *get_dirtyrate_thread(void *arg)
 696 {
 697     struct DirtyRateConfig config = *(struct DirtyRateConfig *)arg;
 698     int ret;
 699     rcu_register_thread();
 700
 701     ret = dirtyrate_set_state(&CalculatingState, DIRTY_RATE_STATUS_UNSTARTED,
 702                               DIRTY_RATE_STATUS_MEASURING);
 703     if (ret == -1) {
 704         error_report("change dirtyrate state failed.");
 705         return NULL;
 706     }
 707
 708     calculate_dirtyrate(config);
 709
 710     ret = dirtyrate_set_state(&CalculatingState, DIRTY_RATE_STATUS_MEASURING,
 711                               DIRTY_RATE_STATUS_MEASURED);
 712     if (ret == -1) {
 713         error_report("change dirtyrate state failed.");
 714     }
 715
 716     rcu_unregister_thread();
 717     return NULL;
 718 }
 719
 720 void qmp_calc_dirty_rate(int64_t calc_time,
 721                          bool has_sample_pages,
 722                          int64_t sample_pages,
 723                          bool has_mode,
 724                          DirtyRateMeasureMode mode,
 725                          Error **errp)
 726 {
 727     static struct DirtyRateConfig config;
 728     QemuThread thread;
 729     int ret;
 730     int64_t start_time;
 731
 732     /*
 733      * If the dirty rate is already being measured, don't attempt to start.
 734      */
 735     if (qatomic_read(&CalculatingState) == DIRTY_RATE_STATUS_MEASURING) {
 736         error_setg(errp, "the dirty rate is already being measured.");
 737         return;
 738     }
 739
 740     if (!is_sample_period_valid(calc_time)) {
 741         error_setg(errp, "calc-time is out of range[%d, %d].",
 742                          MIN_FETCH_DIRTYRATE_TIME_SEC,
 743                          MAX_FETCH_DIRTYRATE_TIME_SEC);
 744         return;
 745     }
 746
 747     if (!has_mode) {
 748         mode =  DIRTY_RATE_MEASURE_MODE_PAGE_SAMPLING;
 749     }
 750
 751     if (has_sample_pages && mode != DIRTY_RATE_MEASURE_MODE_PAGE_SAMPLING) {
 752         error_setg(errp, "sample-pages is used only in page-sampling mode");
 753         return;
 754     }
 755
 756     if (has_sample_pages) {
 757         if (!is_sample_pages_valid(sample_pages)) {
 758             error_setg(errp, "sample-pages is out of range[%d, %d].",
 759                             MIN_SAMPLE_PAGE_COUNT,
 760                             MAX_SAMPLE_PAGE_COUNT);
 761             return;
 762         }
 763     } else {
 764         sample_pages = DIRTYRATE_DEFAULT_SAMPLE_PAGES;
 765     }
 766
 767     /*
 768      * dirty ring mode only works when kvm dirty ring is enabled.
 769      * on the contrary, dirty bitmap mode is not.
 770      */
 771     if (((mode == DIRTY_RATE_MEASURE_MODE_DIRTY_RING) &&
 772         !kvm_dirty_ring_enabled()) ||
 773         ((mode == DIRTY_RATE_MEASURE_MODE_DIRTY_BITMAP) &&
 774          kvm_dirty_ring_enabled())) {
 775         error_setg(errp, "mode %s is not enabled, use other method instead.",
 776                          DirtyRateMeasureMode_str(mode));
 777          return;
 778     }
 779
 780     /*
 781      * Init calculation state as unstarted.
 782      */
 783     ret = dirtyrate_set_state(&CalculatingState, CalculatingState,
 784                               DIRTY_RATE_STATUS_UNSTARTED);
 785     if (ret == -1) {
 786         error_setg(errp, "init dirty rate calculation state failed.");
 787         return;
 788     }
 789
 790     config.sample_period_seconds = calc_time;
 791     config.sample_pages_per_gigabytes = sample_pages;
 792     config.mode = mode;
 793
 794     cleanup_dirtyrate_stat(config);
 795
 796     /*
 797      * update dirty rate mode so that we can figure out what mode has
 798      * been used in last calculation
 799      **/
 800     dirtyrate_mode = mode;
 801
 802     start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) / 1000;
 803     init_dirtyrate_stat(start_time, config);
 804
 805     qemu_thread_create(&thread, "get_dirtyrate", get_dirtyrate_thread,
 806                        (void *)&config, QEMU_THREAD_DETACHED);
 807 }
 808
 809 struct DirtyRateInfo *qmp_query_dirty_rate(Error **errp)
 810 {
 811     return query_dirty_rate_info();
 812 }
 813
 814 void hmp_info_dirty_rate(Monitor *mon, const QDict *qdict)
 815 {
 816     DirtyRateInfo *info = query_dirty_rate_info();
 817
 818     monitor_printf(mon, "Status: %s\n",
 819                    DirtyRateStatus_str(info->status));
 820     monitor_printf(mon, "Start Time: %"PRIi64" (ms)\n",
 821                    info->start_time);
 822     if (info->mode == DIRTY_RATE_MEASURE_MODE_PAGE_SAMPLING) {
 823         monitor_printf(mon, "Sample Pages: %"PRIu64" (per GB)\n",
 824                        info->sample_pages);
 825     }
 826     monitor_printf(mon, "Period: %"PRIi64" (sec)\n",
 827                    info->calc_time);
 828     monitor_printf(mon, "Mode: %s\n",
 829                    DirtyRateMeasureMode_str(info->mode));
 830     monitor_printf(mon, "Dirty rate: ");
 831     if (info->has_dirty_rate) {
 832         monitor_printf(mon, "%"PRIi64" (MB/s)\n", info->dirty_rate);
 833         if (info->has_vcpu_dirty_rate) {
 834             DirtyRateVcpuList *rate, *head = info->vcpu_dirty_rate;
 835             for (rate = head; rate != NULL; rate = rate->next) {
 836                 monitor_printf(mon, "vcpu[%"PRIi64"], Dirty rate: %"PRIi64
 837                                " (MB/s)\n", rate->value->id,
 838                                rate->value->dirty_rate);
 839             }
 840         }
 841     } else {
 842         monitor_printf(mon, "(not ready)\n");
 843     }
 844
 845     qapi_free_DirtyRateVcpuList(info->vcpu_dirty_rate);
 846     g_free(info);
 847 }
 848
 849 void hmp_calc_dirty_rate(Monitor *mon, const QDict *qdict)
 850 {
 851     int64_t sec = qdict_get_try_int(qdict, "second", 0);
 852     int64_t sample_pages = qdict_get_try_int(qdict, "sample_pages_per_GB", -1);
 853     bool has_sample_pages = (sample_pages != -1);
 854     bool dirty_ring = qdict_get_try_bool(qdict, "dirty_ring", false);
 855     bool dirty_bitmap = qdict_get_try_bool(qdict, "dirty_bitmap", false);
 856     DirtyRateMeasureMode mode = DIRTY_RATE_MEASURE_MODE_PAGE_SAMPLING;
 857     Error *err = NULL;
 858
 859     if (!sec) {
 860         monitor_printf(mon, "Incorrect period length specified!\n");
 861         return;
 862     }
 863
 864     if (dirty_ring && dirty_bitmap) {
 865         monitor_printf(mon, "Either dirty ring or dirty bitmap "
 866                        "can be specified!\n");
 867         return;
 868     }
 869
 870     if (dirty_bitmap) {
 871         mode = DIRTY_RATE_MEASURE_MODE_DIRTY_BITMAP;
 872     } else if (dirty_ring) {
 873         mode = DIRTY_RATE_MEASURE_MODE_DIRTY_RING;
 874     }
 875
 876     qmp_calc_dirty_rate(sec, has_sample_pages, sample_pages, true,
 877                         mode, &err);
 878     if (err) {
 879         hmp_handle_error(mon, err);
 880         return;
 881     }
 882
 883     monitor_printf(mon, "Starting dirty rate measurement with period %"PRIi64
 884                    " seconds\n", sec);
 885     monitor_printf(mon, "[Please use 'info dirty_rate' to check results]\n");
 886 }