xref: /qemu/migration/dirtyrate.c (revision 32226db011622fa7b791de3ac02ba67c21947f1d)
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 <zlib.h>
15  #include "qapi/error.h"
16  #include "cpu.h"
17  #include "exec/ramblock.h"
18  #include "exec/ram_addr.h"
19  #include "qemu/rcu_queue.h"
20  #include "qemu/main-loop.h"
21  #include "qapi/qapi-commands-migration.h"
22  #include "ram.h"
23  #include "trace.h"
24  #include "dirtyrate.h"
25  #include "monitor/hmp.h"
26  #include "monitor/monitor.h"
27  #include "qapi/qmp/qdict.h"
28  #include "sysemu/kvm.h"
29  #include "sysemu/runstate.h"
30  #include "exec/memory.h"
31  
32  /*
33   * total_dirty_pages is procted by BQL and is used
34   * to stat dirty pages during the period of two
35   * memory_global_dirty_log_sync
36   */
37  uint64_t total_dirty_pages;
38  
39  typedef struct DirtyPageRecord {
40      uint64_t start_pages;
41      uint64_t end_pages;
42  } DirtyPageRecord;
43  
44  static int CalculatingState = DIRTY_RATE_STATUS_UNSTARTED;
45  static struct DirtyRateStat DirtyStat;
46  static DirtyRateMeasureMode dirtyrate_mode =
47                  DIRTY_RATE_MEASURE_MODE_PAGE_SAMPLING;
48  
49  static int64_t dirty_stat_wait(int64_t msec, int64_t initial_time)
50  {
51      int64_t current_time;
52  
53      current_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
54      if ((current_time - initial_time) >= msec) {
55          msec = current_time - initial_time;
56      } else {
57          g_usleep((msec + initial_time - current_time) * 1000);
58      }
59  
60      return msec;
61  }
62  
63  static inline void record_dirtypages(DirtyPageRecord *dirty_pages,
64                                       CPUState *cpu, bool start)
65  {
66      if (start) {
67          dirty_pages[cpu->cpu_index].start_pages = cpu->dirty_pages;
68      } else {
69          dirty_pages[cpu->cpu_index].end_pages = cpu->dirty_pages;
70      }
71  }
72  
73  static int64_t do_calculate_dirtyrate(DirtyPageRecord dirty_pages,
74                                        int64_t calc_time_ms)
75  {
76      uint64_t memory_size_MB;
77      uint64_t increased_dirty_pages =
78          dirty_pages.end_pages - dirty_pages.start_pages;
79  
80      memory_size_MB = (increased_dirty_pages * TARGET_PAGE_SIZE) >> 20;
81  
82      return memory_size_MB * 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();
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      DirtyPageRecord *records;
115      int nvcpu = 0;
116  
117      CPU_FOREACH(cpu) {
118          nvcpu++;
119      }
120  
121      stat->nvcpu = nvcpu;
122      stat->rates = g_malloc0(sizeof(DirtyRateVcpu) * nvcpu);
123  
124      records = g_malloc0(sizeof(DirtyPageRecord) * nvcpu);
125  
126      return records;
127  }
128  
129  static void vcpu_dirty_stat_collect(VcpuStat *stat,
130                                      DirtyPageRecord *records,
131                                      bool start)
132  {
133      CPUState *cpu;
134  
135      CPU_FOREACH(cpu) {
136          record_dirtypages(records, cpu, start);
137      }
138  }
139  
140  int64_t vcpu_calculate_dirtyrate(int64_t calc_time_ms,
141                                   VcpuStat *stat,
142                                   unsigned int flag,
143                                   bool one_shot)
144  {
145      DirtyPageRecord *records;
146      int64_t init_time_ms;
147      int64_t duration;
148      int64_t dirtyrate;
149      int i = 0;
150      unsigned int gen_id;
151  
152  retry:
153      init_time_ms = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
154  
155      cpu_list_lock();
156      gen_id = cpu_list_generation_id_get();
157      records = vcpu_dirty_stat_alloc(stat);
158      vcpu_dirty_stat_collect(stat, records, true);
159      cpu_list_unlock();
160  
161      duration = dirty_stat_wait(calc_time_ms, init_time_ms);
162  
163      global_dirty_log_sync(flag, one_shot);
164  
165      cpu_list_lock();
166      if (gen_id != cpu_list_generation_id_get()) {
167          g_free(records);
168          g_free(stat->rates);
169          cpu_list_unlock();
170          goto retry;
171      }
172      vcpu_dirty_stat_collect(stat, records, false);
173      cpu_list_unlock();
174  
175      for (i = 0; i < stat->nvcpu; i++) {
176          dirtyrate = do_calculate_dirtyrate(records[i], duration);
177  
178          stat->rates[i].id = i;
179          stat->rates[i].dirty_rate = dirtyrate;
180  
181          trace_dirtyrate_do_calculate_vcpu(i, dirtyrate);
182      }
183  
184      g_free(records);
185  
186      return duration;
187  }
188  
189  static bool is_sample_period_valid(int64_t sec)
190  {
191      if (sec < MIN_FETCH_DIRTYRATE_TIME_SEC ||
192          sec > MAX_FETCH_DIRTYRATE_TIME_SEC) {
193          return false;
194      }
195  
196      return true;
197  }
198  
199  static bool is_sample_pages_valid(int64_t pages)
200  {
201      return pages >= MIN_SAMPLE_PAGE_COUNT &&
202             pages <= MAX_SAMPLE_PAGE_COUNT;
203  }
204  
205  static int dirtyrate_set_state(int *state, int old_state, int new_state)
206  {
207      assert(new_state < DIRTY_RATE_STATUS__MAX);
208      trace_dirtyrate_set_state(DirtyRateStatus_str(new_state));
209      if (qatomic_cmpxchg(state, old_state, new_state) == old_state) {
210          return 0;
211      } else {
212          return -1;
213      }
214  }
215  
216  static struct DirtyRateInfo *query_dirty_rate_info(void)
217  {
218      int i;
219      int64_t dirty_rate = DirtyStat.dirty_rate;
220      struct DirtyRateInfo *info = g_new0(DirtyRateInfo, 1);
221      DirtyRateVcpuList *head = NULL, **tail = &head;
222  
223      info->status = CalculatingState;
224      info->start_time = DirtyStat.start_time;
225      info->calc_time = DirtyStat.calc_time;
226      info->sample_pages = DirtyStat.sample_pages;
227      info->mode = dirtyrate_mode;
228  
229      if (qatomic_read(&CalculatingState) == DIRTY_RATE_STATUS_MEASURED) {
230          info->has_dirty_rate = true;
231          info->dirty_rate = dirty_rate;
232  
233          if (dirtyrate_mode == DIRTY_RATE_MEASURE_MODE_DIRTY_RING) {
234              /*
235               * set sample_pages with 0 to indicate page sampling
236               * isn't enabled
237               **/
238              info->sample_pages = 0;
239              info->has_vcpu_dirty_rate = true;
240              for (i = 0; i < DirtyStat.dirty_ring.nvcpu; i++) {
241                  DirtyRateVcpu *rate = g_new0(DirtyRateVcpu, 1);
242                  rate->id = DirtyStat.dirty_ring.rates[i].id;
243                  rate->dirty_rate = DirtyStat.dirty_ring.rates[i].dirty_rate;
244                  QAPI_LIST_APPEND(tail, rate);
245              }
246              info->vcpu_dirty_rate = head;
247          }
248  
249          if (dirtyrate_mode == DIRTY_RATE_MEASURE_MODE_DIRTY_BITMAP) {
250              info->sample_pages = 0;
251          }
252      }
253  
254      trace_query_dirty_rate_info(DirtyRateStatus_str(CalculatingState));
255  
256      return info;
257  }
258  
259  static void init_dirtyrate_stat(int64_t start_time,
260                                  struct DirtyRateConfig config)
261  {
262      DirtyStat.dirty_rate = -1;
263      DirtyStat.start_time = start_time;
264      DirtyStat.calc_time = config.sample_period_seconds;
265      DirtyStat.sample_pages = config.sample_pages_per_gigabytes;
266  
267      switch (config.mode) {
268      case DIRTY_RATE_MEASURE_MODE_PAGE_SAMPLING:
269          DirtyStat.page_sampling.total_dirty_samples = 0;
270          DirtyStat.page_sampling.total_sample_count = 0;
271          DirtyStat.page_sampling.total_block_mem_MB = 0;
272          break;
273      case DIRTY_RATE_MEASURE_MODE_DIRTY_RING:
274          DirtyStat.dirty_ring.nvcpu = -1;
275          DirtyStat.dirty_ring.rates = NULL;
276          break;
277      default:
278          break;
279      }
280  }
281  
282  static void cleanup_dirtyrate_stat(struct DirtyRateConfig config)
283  {
284      /* last calc-dirty-rate qmp use dirty ring mode */
285      if (dirtyrate_mode == DIRTY_RATE_MEASURE_MODE_DIRTY_RING) {
286          free(DirtyStat.dirty_ring.rates);
287          DirtyStat.dirty_ring.rates = NULL;
288      }
289  }
290  
291  static void update_dirtyrate_stat(struct RamblockDirtyInfo *info)
292  {
293      DirtyStat.page_sampling.total_dirty_samples += info->sample_dirty_count;
294      DirtyStat.page_sampling.total_sample_count += info->sample_pages_count;
295      /* size of total pages in MB */
296      DirtyStat.page_sampling.total_block_mem_MB += (info->ramblock_pages *
297                                                     TARGET_PAGE_SIZE) >> 20;
298  }
299  
300  static void update_dirtyrate(uint64_t msec)
301  {
302      uint64_t dirtyrate;
303      uint64_t total_dirty_samples = DirtyStat.page_sampling.total_dirty_samples;
304      uint64_t total_sample_count = DirtyStat.page_sampling.total_sample_count;
305      uint64_t total_block_mem_MB = DirtyStat.page_sampling.total_block_mem_MB;
306  
307      dirtyrate = total_dirty_samples * total_block_mem_MB *
308                  1000 / (total_sample_count * msec);
309  
310      DirtyStat.dirty_rate = dirtyrate;
311  }
312  
313  /*
314   * get hash result for the sampled memory with length of TARGET_PAGE_SIZE
315   * in ramblock, which starts from ramblock base address.
316   */
317  static uint32_t get_ramblock_vfn_hash(struct RamblockDirtyInfo *info,
318                                        uint64_t vfn)
319  {
320      uint32_t crc;
321  
322      crc = crc32(0, (info->ramblock_addr +
323                  vfn * TARGET_PAGE_SIZE), TARGET_PAGE_SIZE);
324  
325      trace_get_ramblock_vfn_hash(info->idstr, vfn, crc);
326      return crc;
327  }
328  
329  static bool save_ramblock_hash(struct RamblockDirtyInfo *info)
330  {
331      unsigned int sample_pages_count;
332      int i;
333      GRand *rand;
334  
335      sample_pages_count = info->sample_pages_count;
336  
337      /* ramblock size less than one page, return success to skip this ramblock */
338      if (unlikely(info->ramblock_pages == 0 || sample_pages_count == 0)) {
339          return true;
340      }
341  
342      info->hash_result = g_try_malloc0_n(sample_pages_count,
343                                          sizeof(uint32_t));
344      if (!info->hash_result) {
345          return false;
346      }
347  
348      info->sample_page_vfn = g_try_malloc0_n(sample_pages_count,
349                                              sizeof(uint64_t));
350      if (!info->sample_page_vfn) {
351          g_free(info->hash_result);
352          return false;
353      }
354  
355      rand  = g_rand_new();
356      for (i = 0; i < sample_pages_count; i++) {
357          info->sample_page_vfn[i] = g_rand_int_range(rand, 0,
358                                                      info->ramblock_pages - 1);
359          info->hash_result[i] = get_ramblock_vfn_hash(info,
360                                                       info->sample_page_vfn[i]);
361      }
362      g_rand_free(rand);
363  
364      return true;
365  }
366  
367  static void get_ramblock_dirty_info(RAMBlock *block,
368                                      struct RamblockDirtyInfo *info,
369                                      struct DirtyRateConfig *config)
370  {
371      uint64_t sample_pages_per_gigabytes = config->sample_pages_per_gigabytes;
372  
373      /* Right shift 30 bits to calc ramblock size in GB */
374      info->sample_pages_count = (qemu_ram_get_used_length(block) *
375                                  sample_pages_per_gigabytes) >> 30;
376      /* Right shift TARGET_PAGE_BITS to calc page count */
377      info->ramblock_pages = qemu_ram_get_used_length(block) >>
378                             TARGET_PAGE_BITS;
379      info->ramblock_addr = qemu_ram_get_host_addr(block);
380      strcpy(info->idstr, qemu_ram_get_idstr(block));
381  }
382  
383  static void free_ramblock_dirty_info(struct RamblockDirtyInfo *infos, int count)
384  {
385      int i;
386  
387      if (!infos) {
388          return;
389      }
390  
391      for (i = 0; i < count; i++) {
392          g_free(infos[i].sample_page_vfn);
393          g_free(infos[i].hash_result);
394      }
395      g_free(infos);
396  }
397  
398  static bool skip_sample_ramblock(RAMBlock *block)
399  {
400      /*
401       * Sample only blocks larger than MIN_RAMBLOCK_SIZE.
402       */
403      if (qemu_ram_get_used_length(block) < (MIN_RAMBLOCK_SIZE << 10)) {
404          trace_skip_sample_ramblock(block->idstr,
405                                     qemu_ram_get_used_length(block));
406          return true;
407      }
408  
409      return false;
410  }
411  
412  static bool record_ramblock_hash_info(struct RamblockDirtyInfo **block_dinfo,
413                                        struct DirtyRateConfig config,
414                                        int *block_count)
415  {
416      struct RamblockDirtyInfo *info = NULL;
417      struct RamblockDirtyInfo *dinfo = NULL;
418      RAMBlock *block = NULL;
419      int total_count = 0;
420      int index = 0;
421      bool ret = false;
422  
423      RAMBLOCK_FOREACH_MIGRATABLE(block) {
424          if (skip_sample_ramblock(block)) {
425              continue;
426          }
427          total_count++;
428      }
429  
430      dinfo = g_try_malloc0_n(total_count, sizeof(struct RamblockDirtyInfo));
431      if (dinfo == NULL) {
432          goto out;
433      }
434  
435      RAMBLOCK_FOREACH_MIGRATABLE(block) {
436          if (skip_sample_ramblock(block)) {
437              continue;
438          }
439          if (index >= total_count) {
440              break;
441          }
442          info = &dinfo[index];
443          get_ramblock_dirty_info(block, info, &config);
444          if (!save_ramblock_hash(info)) {
445              goto out;
446          }
447          index++;
448      }
449      ret = true;
450  
451  out:
452      *block_count = index;
453      *block_dinfo = dinfo;
454      return ret;
455  }
456  
457  static void calc_page_dirty_rate(struct RamblockDirtyInfo *info)
458  {
459      uint32_t crc;
460      int i;
461  
462      for (i = 0; i < info->sample_pages_count; i++) {
463          crc = get_ramblock_vfn_hash(info, info->sample_page_vfn[i]);
464          if (crc != info->hash_result[i]) {
465              trace_calc_page_dirty_rate(info->idstr, crc, info->hash_result[i]);
466              info->sample_dirty_count++;
467          }
468      }
469  }
470  
471  static struct RamblockDirtyInfo *
472  find_block_matched(RAMBlock *block, int count,
473                    struct RamblockDirtyInfo *infos)
474  {
475      int i;
476      struct RamblockDirtyInfo *matched;
477  
478      for (i = 0; i < count; i++) {
479          if (!strcmp(infos[i].idstr, qemu_ram_get_idstr(block))) {
480              break;
481          }
482      }
483  
484      if (i == count) {
485          return NULL;
486      }
487  
488      if (infos[i].ramblock_addr != qemu_ram_get_host_addr(block) ||
489          infos[i].ramblock_pages !=
490              (qemu_ram_get_used_length(block) >> TARGET_PAGE_BITS)) {
491          trace_find_page_matched(block->idstr);
492          return NULL;
493      }
494  
495      matched = &infos[i];
496  
497      return matched;
498  }
499  
500  static bool compare_page_hash_info(struct RamblockDirtyInfo *info,
501                                    int block_count)
502  {
503      struct RamblockDirtyInfo *block_dinfo = NULL;
504      RAMBlock *block = NULL;
505  
506      RAMBLOCK_FOREACH_MIGRATABLE(block) {
507          if (skip_sample_ramblock(block)) {
508              continue;
509          }
510          block_dinfo = find_block_matched(block, block_count, info);
511          if (block_dinfo == NULL) {
512              continue;
513          }
514          calc_page_dirty_rate(block_dinfo);
515          update_dirtyrate_stat(block_dinfo);
516      }
517  
518      if (DirtyStat.page_sampling.total_sample_count == 0) {
519          return false;
520      }
521  
522      return true;
523  }
524  
525  static inline void record_dirtypages_bitmap(DirtyPageRecord *dirty_pages,
526                                              bool start)
527  {
528      if (start) {
529          dirty_pages->start_pages = total_dirty_pages;
530      } else {
531          dirty_pages->end_pages = total_dirty_pages;
532      }
533  }
534  
535  static inline void dirtyrate_manual_reset_protect(void)
536  {
537      RAMBlock *block = NULL;
538  
539      WITH_RCU_READ_LOCK_GUARD() {
540          RAMBLOCK_FOREACH_MIGRATABLE(block) {
541              memory_region_clear_dirty_bitmap(block->mr, 0,
542                                               block->used_length);
543          }
544      }
545  }
546  
547  static void calculate_dirtyrate_dirty_bitmap(struct DirtyRateConfig config)
548  {
549      int64_t msec = 0;
550      int64_t start_time;
551      DirtyPageRecord dirty_pages;
552  
553      qemu_mutex_lock_iothread();
554      memory_global_dirty_log_start(GLOBAL_DIRTY_DIRTY_RATE);
555  
556      /*
557       * 1'round of log sync may return all 1 bits with
558       * KVM_DIRTY_LOG_INITIALLY_SET enable
559       * skip it unconditionally and start dirty tracking
560       * from 2'round of log sync
561       */
562      memory_global_dirty_log_sync();
563  
564      /*
565       * reset page protect manually and unconditionally.
566       * this make sure kvm dirty log be cleared if
567       * KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE cap is enabled.
568       */
569      dirtyrate_manual_reset_protect();
570      qemu_mutex_unlock_iothread();
571  
572      record_dirtypages_bitmap(&dirty_pages, true);
573  
574      start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
575      DirtyStat.start_time = start_time / 1000;
576  
577      msec = config.sample_period_seconds * 1000;
578      msec = dirty_stat_wait(msec, start_time);
579      DirtyStat.calc_time = msec / 1000;
580  
581      /*
582       * do two things.
583       * 1. fetch dirty bitmap from kvm
584       * 2. stop dirty tracking
585       */
586      global_dirty_log_sync(GLOBAL_DIRTY_DIRTY_RATE, true);
587  
588      record_dirtypages_bitmap(&dirty_pages, false);
589  
590      DirtyStat.dirty_rate = do_calculate_dirtyrate(dirty_pages, msec);
591  }
592  
593  static void calculate_dirtyrate_dirty_ring(struct DirtyRateConfig config)
594  {
595      int64_t duration;
596      uint64_t dirtyrate = 0;
597      uint64_t dirtyrate_sum = 0;
598      int i = 0;
599  
600      /* start log sync */
601      global_dirty_log_change(GLOBAL_DIRTY_DIRTY_RATE, true);
602  
603      DirtyStat.start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) / 1000;
604  
605      /* calculate vcpu dirtyrate */
606      duration = vcpu_calculate_dirtyrate(config.sample_period_seconds * 1000,
607                                          &DirtyStat.dirty_ring,
608                                          GLOBAL_DIRTY_DIRTY_RATE,
609                                          true);
610  
611      DirtyStat.calc_time = duration / 1000;
612  
613      /* calculate vm dirtyrate */
614      for (i = 0; i < DirtyStat.dirty_ring.nvcpu; i++) {
615          dirtyrate = DirtyStat.dirty_ring.rates[i].dirty_rate;
616          DirtyStat.dirty_ring.rates[i].dirty_rate = dirtyrate;
617          dirtyrate_sum += dirtyrate;
618      }
619  
620      DirtyStat.dirty_rate = dirtyrate_sum;
621  }
622  
623  static void calculate_dirtyrate_sample_vm(struct DirtyRateConfig config)
624  {
625      struct RamblockDirtyInfo *block_dinfo = NULL;
626      int block_count = 0;
627      int64_t msec = 0;
628      int64_t initial_time;
629  
630      rcu_read_lock();
631      initial_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
632      if (!record_ramblock_hash_info(&block_dinfo, config, &block_count)) {
633          goto out;
634      }
635      rcu_read_unlock();
636  
637      msec = config.sample_period_seconds * 1000;
638      msec = dirty_stat_wait(msec, initial_time);
639      DirtyStat.start_time = initial_time / 1000;
640      DirtyStat.calc_time = msec / 1000;
641  
642      rcu_read_lock();
643      if (!compare_page_hash_info(block_dinfo, block_count)) {
644          goto out;
645      }
646  
647      update_dirtyrate(msec);
648  
649  out:
650      rcu_read_unlock();
651      free_ramblock_dirty_info(block_dinfo, block_count);
652  }
653  
654  static void calculate_dirtyrate(struct DirtyRateConfig config)
655  {
656      if (config.mode == DIRTY_RATE_MEASURE_MODE_DIRTY_BITMAP) {
657          calculate_dirtyrate_dirty_bitmap(config);
658      } else if (config.mode == DIRTY_RATE_MEASURE_MODE_DIRTY_RING) {
659          calculate_dirtyrate_dirty_ring(config);
660      } else {
661          calculate_dirtyrate_sample_vm(config);
662      }
663  
664      trace_dirtyrate_calculate(DirtyStat.dirty_rate);
665  }
666  
667  void *get_dirtyrate_thread(void *arg)
668  {
669      struct DirtyRateConfig config = *(struct DirtyRateConfig *)arg;
670      int ret;
671      rcu_register_thread();
672  
673      ret = dirtyrate_set_state(&CalculatingState, DIRTY_RATE_STATUS_UNSTARTED,
674                                DIRTY_RATE_STATUS_MEASURING);
675      if (ret == -1) {
676          error_report("change dirtyrate state failed.");
677          return NULL;
678      }
679  
680      calculate_dirtyrate(config);
681  
682      ret = dirtyrate_set_state(&CalculatingState, DIRTY_RATE_STATUS_MEASURING,
683                                DIRTY_RATE_STATUS_MEASURED);
684      if (ret == -1) {
685          error_report("change dirtyrate state failed.");
686      }
687  
688      rcu_unregister_thread();
689      return NULL;
690  }
691  
692  void qmp_calc_dirty_rate(int64_t calc_time,
693                           bool has_sample_pages,
694                           int64_t sample_pages,
695                           bool has_mode,
696                           DirtyRateMeasureMode mode,
697                           Error **errp)
698  {
699      static struct DirtyRateConfig config;
700      QemuThread thread;
701      int ret;
702      int64_t start_time;
703  
704      /*
705       * If the dirty rate is already being measured, don't attempt to start.
706       */
707      if (qatomic_read(&CalculatingState) == DIRTY_RATE_STATUS_MEASURING) {
708          error_setg(errp, "the dirty rate is already being measured.");
709          return;
710      }
711  
712      if (!is_sample_period_valid(calc_time)) {
713          error_setg(errp, "calc-time is out of range[%d, %d].",
714                           MIN_FETCH_DIRTYRATE_TIME_SEC,
715                           MAX_FETCH_DIRTYRATE_TIME_SEC);
716          return;
717      }
718  
719      if (!has_mode) {
720          mode =  DIRTY_RATE_MEASURE_MODE_PAGE_SAMPLING;
721      }
722  
723      if (has_sample_pages && mode == DIRTY_RATE_MEASURE_MODE_DIRTY_RING) {
724          error_setg(errp, "either sample-pages or dirty-ring can be specified.");
725          return;
726      }
727  
728      if (has_sample_pages) {
729          if (!is_sample_pages_valid(sample_pages)) {
730              error_setg(errp, "sample-pages is out of range[%d, %d].",
731                              MIN_SAMPLE_PAGE_COUNT,
732                              MAX_SAMPLE_PAGE_COUNT);
733              return;
734          }
735      } else {
736          sample_pages = DIRTYRATE_DEFAULT_SAMPLE_PAGES;
737      }
738  
739      /*
740       * dirty ring mode only works when kvm dirty ring is enabled.
741       * on the contrary, dirty bitmap mode is not.
742       */
743      if (((mode == DIRTY_RATE_MEASURE_MODE_DIRTY_RING) &&
744          !kvm_dirty_ring_enabled()) ||
745          ((mode == DIRTY_RATE_MEASURE_MODE_DIRTY_BITMAP) &&
746           kvm_dirty_ring_enabled())) {
747          error_setg(errp, "mode %s is not enabled, use other method instead.",
748                           DirtyRateMeasureMode_str(mode));
749           return;
750      }
751  
752      /*
753       * Init calculation state as unstarted.
754       */
755      ret = dirtyrate_set_state(&CalculatingState, CalculatingState,
756                                DIRTY_RATE_STATUS_UNSTARTED);
757      if (ret == -1) {
758          error_setg(errp, "init dirty rate calculation state failed.");
759          return;
760      }
761  
762      config.sample_period_seconds = calc_time;
763      config.sample_pages_per_gigabytes = sample_pages;
764      config.mode = mode;
765  
766      cleanup_dirtyrate_stat(config);
767  
768      /*
769       * update dirty rate mode so that we can figure out what mode has
770       * been used in last calculation
771       **/
772      dirtyrate_mode = mode;
773  
774      start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) / 1000;
775      init_dirtyrate_stat(start_time, config);
776  
777      qemu_thread_create(&thread, "get_dirtyrate", get_dirtyrate_thread,
778                         (void *)&config, QEMU_THREAD_DETACHED);
779  }
780  
781  struct DirtyRateInfo *qmp_query_dirty_rate(Error **errp)
782  {
783      return query_dirty_rate_info();
784  }
785  
786  void hmp_info_dirty_rate(Monitor *mon, const QDict *qdict)
787  {
788      DirtyRateInfo *info = query_dirty_rate_info();
789  
790      monitor_printf(mon, "Status: %s\n",
791                     DirtyRateStatus_str(info->status));
792      monitor_printf(mon, "Start Time: %"PRIi64" (ms)\n",
793                     info->start_time);
794      monitor_printf(mon, "Sample Pages: %"PRIu64" (per GB)\n",
795                     info->sample_pages);
796      monitor_printf(mon, "Period: %"PRIi64" (sec)\n",
797                     info->calc_time);
798      monitor_printf(mon, "Mode: %s\n",
799                     DirtyRateMeasureMode_str(info->mode));
800      monitor_printf(mon, "Dirty rate: ");
801      if (info->has_dirty_rate) {
802          monitor_printf(mon, "%"PRIi64" (MB/s)\n", info->dirty_rate);
803          if (info->has_vcpu_dirty_rate) {
804              DirtyRateVcpuList *rate, *head = info->vcpu_dirty_rate;
805              for (rate = head; rate != NULL; rate = rate->next) {
806                  monitor_printf(mon, "vcpu[%"PRIi64"], Dirty rate: %"PRIi64
807                                 " (MB/s)\n", rate->value->id,
808                                 rate->value->dirty_rate);
809              }
810          }
811      } else {
812          monitor_printf(mon, "(not ready)\n");
813      }
814  
815      qapi_free_DirtyRateVcpuList(info->vcpu_dirty_rate);
816      g_free(info);
817  }
818  
819  void hmp_calc_dirty_rate(Monitor *mon, const QDict *qdict)
820  {
821      int64_t sec = qdict_get_try_int(qdict, "second", 0);
822      int64_t sample_pages = qdict_get_try_int(qdict, "sample_pages_per_GB", -1);
823      bool has_sample_pages = (sample_pages != -1);
824      bool dirty_ring = qdict_get_try_bool(qdict, "dirty_ring", false);
825      bool dirty_bitmap = qdict_get_try_bool(qdict, "dirty_bitmap", false);
826      DirtyRateMeasureMode mode = DIRTY_RATE_MEASURE_MODE_PAGE_SAMPLING;
827      Error *err = NULL;
828  
829      if (!sec) {
830          monitor_printf(mon, "Incorrect period length specified!\n");
831          return;
832      }
833  
834      if (dirty_ring && dirty_bitmap) {
835          monitor_printf(mon, "Either dirty ring or dirty bitmap "
836                         "can be specified!\n");
837          return;
838      }
839  
840      if (dirty_bitmap) {
841          mode = DIRTY_RATE_MEASURE_MODE_DIRTY_BITMAP;
842      } else if (dirty_ring) {
843          mode = DIRTY_RATE_MEASURE_MODE_DIRTY_RING;
844      }
845  
846      qmp_calc_dirty_rate(sec, has_sample_pages, sample_pages, true,
847                          mode, &err);
848      if (err) {
849          hmp_handle_error(mon, err);
850          return;
851      }
852  
853      monitor_printf(mon, "Starting dirty rate measurement with period %"PRIi64
854                     " seconds\n", sec);
855      monitor_printf(mon, "[Please use 'info dirty_rate' to check results]\n");
856  }
857