xref: /openbmc/qemu/migration/dirtyrate.c (revision 7a6e869c)
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     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     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     cpu_list_unlock();
157 
158     duration = dirty_stat_wait(calc_time_ms, init_time_ms);
159 
160     global_dirty_log_sync(flag, one_shot);
161 
162     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     cpu_list_unlock();
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 += (info->ramblock_pages *
294                                                    TARGET_PAGE_SIZE) >> 20;
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  * get hash result for the sampled memory with length of TARGET_PAGE_SIZE
312  * in ramblock, which starts from ramblock base address.
313  */
314 static uint32_t get_ramblock_vfn_hash(struct RamblockDirtyInfo *info,
315                                       uint64_t vfn)
316 {
317     uint32_t crc;
318 
319     crc = crc32(0, (info->ramblock_addr +
320                 vfn * TARGET_PAGE_SIZE), TARGET_PAGE_SIZE);
321 
322     trace_get_ramblock_vfn_hash(info->idstr, vfn, crc);
323     return crc;
324 }
325 
326 static bool save_ramblock_hash(struct RamblockDirtyInfo *info)
327 {
328     unsigned int sample_pages_count;
329     int i;
330     GRand *rand;
331 
332     sample_pages_count = info->sample_pages_count;
333 
334     /* ramblock size less than one page, return success to skip this ramblock */
335     if (unlikely(info->ramblock_pages == 0 || sample_pages_count == 0)) {
336         return true;
337     }
338 
339     info->hash_result = g_try_malloc0_n(sample_pages_count,
340                                         sizeof(uint32_t));
341     if (!info->hash_result) {
342         return false;
343     }
344 
345     info->sample_page_vfn = g_try_malloc0_n(sample_pages_count,
346                                             sizeof(uint64_t));
347     if (!info->sample_page_vfn) {
348         g_free(info->hash_result);
349         return false;
350     }
351 
352     rand  = g_rand_new();
353     for (i = 0; i < sample_pages_count; i++) {
354         info->sample_page_vfn[i] = g_rand_int_range(rand, 0,
355                                                     info->ramblock_pages - 1);
356         info->hash_result[i] = get_ramblock_vfn_hash(info,
357                                                      info->sample_page_vfn[i]);
358     }
359     g_rand_free(rand);
360 
361     return true;
362 }
363 
364 static void get_ramblock_dirty_info(RAMBlock *block,
365                                     struct RamblockDirtyInfo *info,
366                                     struct DirtyRateConfig *config)
367 {
368     uint64_t sample_pages_per_gigabytes = config->sample_pages_per_gigabytes;
369 
370     /* Right shift 30 bits to calc ramblock size in GB */
371     info->sample_pages_count = (qemu_ram_get_used_length(block) *
372                                 sample_pages_per_gigabytes) >> 30;
373     /* Right shift TARGET_PAGE_BITS to calc page count */
374     info->ramblock_pages = qemu_ram_get_used_length(block) >>
375                            TARGET_PAGE_BITS;
376     info->ramblock_addr = qemu_ram_get_host_addr(block);
377     strcpy(info->idstr, qemu_ram_get_idstr(block));
378 }
379 
380 static void free_ramblock_dirty_info(struct RamblockDirtyInfo *infos, int count)
381 {
382     int i;
383 
384     if (!infos) {
385         return;
386     }
387 
388     for (i = 0; i < count; i++) {
389         g_free(infos[i].sample_page_vfn);
390         g_free(infos[i].hash_result);
391     }
392     g_free(infos);
393 }
394 
395 static bool skip_sample_ramblock(RAMBlock *block)
396 {
397     /*
398      * Sample only blocks larger than MIN_RAMBLOCK_SIZE.
399      */
400     if (qemu_ram_get_used_length(block) < (MIN_RAMBLOCK_SIZE << 10)) {
401         trace_skip_sample_ramblock(block->idstr,
402                                    qemu_ram_get_used_length(block));
403         return true;
404     }
405 
406     return false;
407 }
408 
409 static bool record_ramblock_hash_info(struct RamblockDirtyInfo **block_dinfo,
410                                       struct DirtyRateConfig config,
411                                       int *block_count)
412 {
413     struct RamblockDirtyInfo *info = NULL;
414     struct RamblockDirtyInfo *dinfo = NULL;
415     RAMBlock *block = NULL;
416     int total_count = 0;
417     int index = 0;
418     bool ret = false;
419 
420     RAMBLOCK_FOREACH_MIGRATABLE(block) {
421         if (skip_sample_ramblock(block)) {
422             continue;
423         }
424         total_count++;
425     }
426 
427     dinfo = g_try_malloc0_n(total_count, sizeof(struct RamblockDirtyInfo));
428     if (dinfo == NULL) {
429         goto out;
430     }
431 
432     RAMBLOCK_FOREACH_MIGRATABLE(block) {
433         if (skip_sample_ramblock(block)) {
434             continue;
435         }
436         if (index >= total_count) {
437             break;
438         }
439         info = &dinfo[index];
440         get_ramblock_dirty_info(block, info, &config);
441         if (!save_ramblock_hash(info)) {
442             goto out;
443         }
444         index++;
445     }
446     ret = true;
447 
448 out:
449     *block_count = index;
450     *block_dinfo = dinfo;
451     return ret;
452 }
453 
454 static void calc_page_dirty_rate(struct RamblockDirtyInfo *info)
455 {
456     uint32_t crc;
457     int i;
458 
459     for (i = 0; i < info->sample_pages_count; i++) {
460         crc = get_ramblock_vfn_hash(info, info->sample_page_vfn[i]);
461         if (crc != info->hash_result[i]) {
462             trace_calc_page_dirty_rate(info->idstr, crc, info->hash_result[i]);
463             info->sample_dirty_count++;
464         }
465     }
466 }
467 
468 static struct RamblockDirtyInfo *
469 find_block_matched(RAMBlock *block, int count,
470                   struct RamblockDirtyInfo *infos)
471 {
472     int i;
473 
474     for (i = 0; i < count; i++) {
475         if (!strcmp(infos[i].idstr, qemu_ram_get_idstr(block))) {
476             break;
477         }
478     }
479 
480     if (i == count) {
481         return NULL;
482     }
483 
484     if (infos[i].ramblock_addr != qemu_ram_get_host_addr(block) ||
485         infos[i].ramblock_pages !=
486             (qemu_ram_get_used_length(block) >> TARGET_PAGE_BITS)) {
487         trace_find_page_matched(block->idstr);
488         return NULL;
489     }
490 
491     return &infos[i];
492 }
493 
494 static bool compare_page_hash_info(struct RamblockDirtyInfo *info,
495                                   int block_count)
496 {
497     struct RamblockDirtyInfo *block_dinfo = NULL;
498     RAMBlock *block = NULL;
499 
500     RAMBLOCK_FOREACH_MIGRATABLE(block) {
501         if (skip_sample_ramblock(block)) {
502             continue;
503         }
504         block_dinfo = find_block_matched(block, block_count, info);
505         if (block_dinfo == NULL) {
506             continue;
507         }
508         calc_page_dirty_rate(block_dinfo);
509         update_dirtyrate_stat(block_dinfo);
510     }
511 
512     if (DirtyStat.page_sampling.total_sample_count == 0) {
513         return false;
514     }
515 
516     return true;
517 }
518 
519 static inline void record_dirtypages_bitmap(DirtyPageRecord *dirty_pages,
520                                             bool start)
521 {
522     if (start) {
523         dirty_pages->start_pages = total_dirty_pages;
524     } else {
525         dirty_pages->end_pages = total_dirty_pages;
526     }
527 }
528 
529 static inline void dirtyrate_manual_reset_protect(void)
530 {
531     RAMBlock *block = NULL;
532 
533     WITH_RCU_READ_LOCK_GUARD() {
534         RAMBLOCK_FOREACH_MIGRATABLE(block) {
535             memory_region_clear_dirty_bitmap(block->mr, 0,
536                                              block->used_length);
537         }
538     }
539 }
540 
541 static void calculate_dirtyrate_dirty_bitmap(struct DirtyRateConfig config)
542 {
543     int64_t msec = 0;
544     int64_t start_time;
545     DirtyPageRecord dirty_pages;
546 
547     qemu_mutex_lock_iothread();
548     memory_global_dirty_log_start(GLOBAL_DIRTY_DIRTY_RATE);
549 
550     /*
551      * 1'round of log sync may return all 1 bits with
552      * KVM_DIRTY_LOG_INITIALLY_SET enable
553      * skip it unconditionally and start dirty tracking
554      * from 2'round of log sync
555      */
556     memory_global_dirty_log_sync();
557 
558     /*
559      * reset page protect manually and unconditionally.
560      * this make sure kvm dirty log be cleared if
561      * KVM_DIRTY_LOG_MANUAL_PROTECT_ENABLE cap is enabled.
562      */
563     dirtyrate_manual_reset_protect();
564     qemu_mutex_unlock_iothread();
565 
566     record_dirtypages_bitmap(&dirty_pages, true);
567 
568     start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
569     DirtyStat.start_time = start_time / 1000;
570 
571     msec = config.sample_period_seconds * 1000;
572     msec = dirty_stat_wait(msec, start_time);
573     DirtyStat.calc_time = msec / 1000;
574 
575     /*
576      * do two things.
577      * 1. fetch dirty bitmap from kvm
578      * 2. stop dirty tracking
579      */
580     global_dirty_log_sync(GLOBAL_DIRTY_DIRTY_RATE, true);
581 
582     record_dirtypages_bitmap(&dirty_pages, false);
583 
584     DirtyStat.dirty_rate = do_calculate_dirtyrate(dirty_pages, msec);
585 }
586 
587 static void calculate_dirtyrate_dirty_ring(struct DirtyRateConfig config)
588 {
589     int64_t duration;
590     uint64_t dirtyrate = 0;
591     uint64_t dirtyrate_sum = 0;
592     int i = 0;
593 
594     /* start log sync */
595     global_dirty_log_change(GLOBAL_DIRTY_DIRTY_RATE, true);
596 
597     DirtyStat.start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) / 1000;
598 
599     /* calculate vcpu dirtyrate */
600     duration = vcpu_calculate_dirtyrate(config.sample_period_seconds * 1000,
601                                         &DirtyStat.dirty_ring,
602                                         GLOBAL_DIRTY_DIRTY_RATE,
603                                         true);
604 
605     DirtyStat.calc_time = duration / 1000;
606 
607     /* calculate vm dirtyrate */
608     for (i = 0; i < DirtyStat.dirty_ring.nvcpu; i++) {
609         dirtyrate = DirtyStat.dirty_ring.rates[i].dirty_rate;
610         DirtyStat.dirty_ring.rates[i].dirty_rate = dirtyrate;
611         dirtyrate_sum += dirtyrate;
612     }
613 
614     DirtyStat.dirty_rate = dirtyrate_sum;
615 }
616 
617 static void calculate_dirtyrate_sample_vm(struct DirtyRateConfig config)
618 {
619     struct RamblockDirtyInfo *block_dinfo = NULL;
620     int block_count = 0;
621     int64_t msec = 0;
622     int64_t initial_time;
623 
624     rcu_read_lock();
625     initial_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
626     if (!record_ramblock_hash_info(&block_dinfo, config, &block_count)) {
627         goto out;
628     }
629     rcu_read_unlock();
630 
631     msec = config.sample_period_seconds * 1000;
632     msec = dirty_stat_wait(msec, initial_time);
633     DirtyStat.start_time = initial_time / 1000;
634     DirtyStat.calc_time = msec / 1000;
635 
636     rcu_read_lock();
637     if (!compare_page_hash_info(block_dinfo, block_count)) {
638         goto out;
639     }
640 
641     update_dirtyrate(msec);
642 
643 out:
644     rcu_read_unlock();
645     free_ramblock_dirty_info(block_dinfo, block_count);
646 }
647 
648 static void calculate_dirtyrate(struct DirtyRateConfig config)
649 {
650     if (config.mode == DIRTY_RATE_MEASURE_MODE_DIRTY_BITMAP) {
651         calculate_dirtyrate_dirty_bitmap(config);
652     } else if (config.mode == DIRTY_RATE_MEASURE_MODE_DIRTY_RING) {
653         calculate_dirtyrate_dirty_ring(config);
654     } else {
655         calculate_dirtyrate_sample_vm(config);
656     }
657 
658     trace_dirtyrate_calculate(DirtyStat.dirty_rate);
659 }
660 
661 void *get_dirtyrate_thread(void *arg)
662 {
663     struct DirtyRateConfig config = *(struct DirtyRateConfig *)arg;
664     int ret;
665     rcu_register_thread();
666 
667     ret = dirtyrate_set_state(&CalculatingState, DIRTY_RATE_STATUS_UNSTARTED,
668                               DIRTY_RATE_STATUS_MEASURING);
669     if (ret == -1) {
670         error_report("change dirtyrate state failed.");
671         return NULL;
672     }
673 
674     calculate_dirtyrate(config);
675 
676     ret = dirtyrate_set_state(&CalculatingState, DIRTY_RATE_STATUS_MEASURING,
677                               DIRTY_RATE_STATUS_MEASURED);
678     if (ret == -1) {
679         error_report("change dirtyrate state failed.");
680     }
681 
682     rcu_unregister_thread();
683     return NULL;
684 }
685 
686 void qmp_calc_dirty_rate(int64_t calc_time,
687                          bool has_sample_pages,
688                          int64_t sample_pages,
689                          bool has_mode,
690                          DirtyRateMeasureMode mode,
691                          Error **errp)
692 {
693     static struct DirtyRateConfig config;
694     QemuThread thread;
695     int ret;
696     int64_t start_time;
697 
698     /*
699      * If the dirty rate is already being measured, don't attempt to start.
700      */
701     if (qatomic_read(&CalculatingState) == DIRTY_RATE_STATUS_MEASURING) {
702         error_setg(errp, "the dirty rate is already being measured.");
703         return;
704     }
705 
706     if (!is_sample_period_valid(calc_time)) {
707         error_setg(errp, "calc-time is out of range[%d, %d].",
708                          MIN_FETCH_DIRTYRATE_TIME_SEC,
709                          MAX_FETCH_DIRTYRATE_TIME_SEC);
710         return;
711     }
712 
713     if (!has_mode) {
714         mode =  DIRTY_RATE_MEASURE_MODE_PAGE_SAMPLING;
715     }
716 
717     if (has_sample_pages && mode == DIRTY_RATE_MEASURE_MODE_DIRTY_RING) {
718         error_setg(errp, "either sample-pages or dirty-ring can be specified.");
719         return;
720     }
721 
722     if (has_sample_pages) {
723         if (!is_sample_pages_valid(sample_pages)) {
724             error_setg(errp, "sample-pages is out of range[%d, %d].",
725                             MIN_SAMPLE_PAGE_COUNT,
726                             MAX_SAMPLE_PAGE_COUNT);
727             return;
728         }
729     } else {
730         sample_pages = DIRTYRATE_DEFAULT_SAMPLE_PAGES;
731     }
732 
733     /*
734      * dirty ring mode only works when kvm dirty ring is enabled.
735      * on the contrary, dirty bitmap mode is not.
736      */
737     if (((mode == DIRTY_RATE_MEASURE_MODE_DIRTY_RING) &&
738         !kvm_dirty_ring_enabled()) ||
739         ((mode == DIRTY_RATE_MEASURE_MODE_DIRTY_BITMAP) &&
740          kvm_dirty_ring_enabled())) {
741         error_setg(errp, "mode %s is not enabled, use other method instead.",
742                          DirtyRateMeasureMode_str(mode));
743          return;
744     }
745 
746     /*
747      * Init calculation state as unstarted.
748      */
749     ret = dirtyrate_set_state(&CalculatingState, CalculatingState,
750                               DIRTY_RATE_STATUS_UNSTARTED);
751     if (ret == -1) {
752         error_setg(errp, "init dirty rate calculation state failed.");
753         return;
754     }
755 
756     config.sample_period_seconds = calc_time;
757     config.sample_pages_per_gigabytes = sample_pages;
758     config.mode = mode;
759 
760     cleanup_dirtyrate_stat(config);
761 
762     /*
763      * update dirty rate mode so that we can figure out what mode has
764      * been used in last calculation
765      **/
766     dirtyrate_mode = mode;
767 
768     start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) / 1000;
769     init_dirtyrate_stat(start_time, config);
770 
771     qemu_thread_create(&thread, "get_dirtyrate", get_dirtyrate_thread,
772                        (void *)&config, QEMU_THREAD_DETACHED);
773 }
774 
775 struct DirtyRateInfo *qmp_query_dirty_rate(Error **errp)
776 {
777     return query_dirty_rate_info();
778 }
779 
780 void hmp_info_dirty_rate(Monitor *mon, const QDict *qdict)
781 {
782     DirtyRateInfo *info = query_dirty_rate_info();
783 
784     monitor_printf(mon, "Status: %s\n",
785                    DirtyRateStatus_str(info->status));
786     monitor_printf(mon, "Start Time: %"PRIi64" (ms)\n",
787                    info->start_time);
788     monitor_printf(mon, "Sample Pages: %"PRIu64" (per GB)\n",
789                    info->sample_pages);
790     monitor_printf(mon, "Period: %"PRIi64" (sec)\n",
791                    info->calc_time);
792     monitor_printf(mon, "Mode: %s\n",
793                    DirtyRateMeasureMode_str(info->mode));
794     monitor_printf(mon, "Dirty rate: ");
795     if (info->has_dirty_rate) {
796         monitor_printf(mon, "%"PRIi64" (MB/s)\n", info->dirty_rate);
797         if (info->has_vcpu_dirty_rate) {
798             DirtyRateVcpuList *rate, *head = info->vcpu_dirty_rate;
799             for (rate = head; rate != NULL; rate = rate->next) {
800                 monitor_printf(mon, "vcpu[%"PRIi64"], Dirty rate: %"PRIi64
801                                " (MB/s)\n", rate->value->id,
802                                rate->value->dirty_rate);
803             }
804         }
805     } else {
806         monitor_printf(mon, "(not ready)\n");
807     }
808 
809     qapi_free_DirtyRateVcpuList(info->vcpu_dirty_rate);
810     g_free(info);
811 }
812 
813 void hmp_calc_dirty_rate(Monitor *mon, const QDict *qdict)
814 {
815     int64_t sec = qdict_get_try_int(qdict, "second", 0);
816     int64_t sample_pages = qdict_get_try_int(qdict, "sample_pages_per_GB", -1);
817     bool has_sample_pages = (sample_pages != -1);
818     bool dirty_ring = qdict_get_try_bool(qdict, "dirty_ring", false);
819     bool dirty_bitmap = qdict_get_try_bool(qdict, "dirty_bitmap", false);
820     DirtyRateMeasureMode mode = DIRTY_RATE_MEASURE_MODE_PAGE_SAMPLING;
821     Error *err = NULL;
822 
823     if (!sec) {
824         monitor_printf(mon, "Incorrect period length specified!\n");
825         return;
826     }
827 
828     if (dirty_ring && dirty_bitmap) {
829         monitor_printf(mon, "Either dirty ring or dirty bitmap "
830                        "can be specified!\n");
831         return;
832     }
833 
834     if (dirty_bitmap) {
835         mode = DIRTY_RATE_MEASURE_MODE_DIRTY_BITMAP;
836     } else if (dirty_ring) {
837         mode = DIRTY_RATE_MEASURE_MODE_DIRTY_RING;
838     }
839 
840     qmp_calc_dirty_rate(sec, has_sample_pages, sample_pages, true,
841                         mode, &err);
842     if (err) {
843         hmp_handle_error(mon, err);
844         return;
845     }
846 
847     monitor_printf(mon, "Starting dirty rate measurement with period %"PRIi64
848                    " seconds\n", sec);
849     monitor_printf(mon, "[Please use 'info dirty_rate' to check results]\n");
850 }
851