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25#include "qemu/osdep.h"
26#include "qapi/error.h"
27#include "qemu/throttle.h"
28#include "qemu/timer.h"
29#include "block/aio.h"
30
31
32
33
34
35
36void throttle_leak_bucket(LeakyBucket *bkt, int64_t delta_ns)
37{
38 double leak;
39
40
41 leak = (bkt->avg * (double) delta_ns) / NANOSECONDS_PER_SECOND;
42
43
44 bkt->level = MAX(bkt->level - leak, 0);
45
46
47
48
49 if (bkt->burst_length > 1) {
50 leak = (bkt->max * (double) delta_ns) / NANOSECONDS_PER_SECOND;
51 bkt->burst_level = MAX(bkt->burst_level - leak, 0);
52 }
53}
54
55
56
57
58
59static void throttle_do_leak(ThrottleState *ts, int64_t now)
60{
61
62 int64_t delta_ns = now - ts->previous_leak;
63 int i;
64
65 ts->previous_leak = now;
66
67 if (delta_ns <= 0) {
68 return;
69 }
70
71
72 for (i = 0; i < BUCKETS_COUNT; i++) {
73 throttle_leak_bucket(&ts->cfg.buckets[i], delta_ns);
74 }
75}
76
77
78
79
80
81
82
83static int64_t throttle_do_compute_wait(double limit, double extra)
84{
85 double wait = extra * NANOSECONDS_PER_SECOND;
86 wait /= limit;
87 return wait;
88}
89
90
91
92
93
94
95int64_t throttle_compute_wait(LeakyBucket *bkt)
96{
97 double extra;
98
99 if (!bkt->avg) {
100 return 0;
101 }
102
103
104 extra = bkt->level - bkt->max * bkt->burst_length;
105 if (extra > 0) {
106 return throttle_do_compute_wait(bkt->avg, extra);
107 }
108
109
110
111 if (bkt->burst_length > 1) {
112
113
114 extra = bkt->burst_level - bkt->max / 10;
115 if (extra > 0) {
116 return throttle_do_compute_wait(bkt->max, extra);
117 }
118 }
119
120 return 0;
121}
122
123
124
125
126
127
128static int64_t throttle_compute_wait_for(ThrottleState *ts,
129 bool is_write)
130{
131 BucketType to_check[2][4] = { {THROTTLE_BPS_TOTAL,
132 THROTTLE_OPS_TOTAL,
133 THROTTLE_BPS_READ,
134 THROTTLE_OPS_READ},
135 {THROTTLE_BPS_TOTAL,
136 THROTTLE_OPS_TOTAL,
137 THROTTLE_BPS_WRITE,
138 THROTTLE_OPS_WRITE}, };
139 int64_t wait, max_wait = 0;
140 int i;
141
142 for (i = 0; i < 4; i++) {
143 BucketType index = to_check[is_write][i];
144 wait = throttle_compute_wait(&ts->cfg.buckets[index]);
145 if (wait > max_wait) {
146 max_wait = wait;
147 }
148 }
149
150 return max_wait;
151}
152
153
154
155
156
157
158
159
160static bool throttle_compute_timer(ThrottleState *ts,
161 bool is_write,
162 int64_t now,
163 int64_t *next_timestamp)
164{
165 int64_t wait;
166
167
168 throttle_do_leak(ts, now);
169
170
171 wait = throttle_compute_wait_for(ts, is_write);
172
173
174 if (wait) {
175 *next_timestamp = now + wait;
176 return true;
177 }
178
179
180 *next_timestamp = now;
181 return false;
182}
183
184
185void throttle_timers_attach_aio_context(ThrottleTimers *tt,
186 AioContext *new_context)
187{
188 tt->timers[0] = aio_timer_new(new_context, tt->clock_type, SCALE_NS,
189 tt->read_timer_cb, tt->timer_opaque);
190 tt->timers[1] = aio_timer_new(new_context, tt->clock_type, SCALE_NS,
191 tt->write_timer_cb, tt->timer_opaque);
192}
193
194
195
196
197
198void throttle_config_init(ThrottleConfig *cfg)
199{
200 unsigned i;
201 memset(cfg, 0, sizeof(*cfg));
202 for (i = 0; i < BUCKETS_COUNT; i++) {
203 cfg->buckets[i].burst_length = 1;
204 }
205}
206
207
208void throttle_init(ThrottleState *ts)
209{
210 memset(ts, 0, sizeof(ThrottleState));
211 throttle_config_init(&ts->cfg);
212}
213
214
215void throttle_timers_init(ThrottleTimers *tt,
216 AioContext *aio_context,
217 QEMUClockType clock_type,
218 QEMUTimerCB *read_timer_cb,
219 QEMUTimerCB *write_timer_cb,
220 void *timer_opaque)
221{
222 memset(tt, 0, sizeof(ThrottleTimers));
223
224 tt->clock_type = clock_type;
225 tt->read_timer_cb = read_timer_cb;
226 tt->write_timer_cb = write_timer_cb;
227 tt->timer_opaque = timer_opaque;
228 throttle_timers_attach_aio_context(tt, aio_context);
229}
230
231
232static void throttle_timer_destroy(QEMUTimer **timer)
233{
234 assert(*timer != NULL);
235
236 timer_del(*timer);
237 timer_free(*timer);
238 *timer = NULL;
239}
240
241
242void throttle_timers_detach_aio_context(ThrottleTimers *tt)
243{
244 int i;
245
246 for (i = 0; i < 2; i++) {
247 throttle_timer_destroy(&tt->timers[i]);
248 }
249}
250
251
252void throttle_timers_destroy(ThrottleTimers *tt)
253{
254 throttle_timers_detach_aio_context(tt);
255}
256
257
258bool throttle_timers_are_initialized(ThrottleTimers *tt)
259{
260 if (tt->timers[0]) {
261 return true;
262 }
263
264 return false;
265}
266
267
268
269
270
271
272bool throttle_enabled(ThrottleConfig *cfg)
273{
274 int i;
275
276 for (i = 0; i < BUCKETS_COUNT; i++) {
277 if (cfg->buckets[i].avg > 0) {
278 return true;
279 }
280 }
281
282 return false;
283}
284
285
286
287
288
289
290bool throttle_is_valid(ThrottleConfig *cfg, Error **errp)
291{
292 int i;
293 bool bps_flag, ops_flag;
294 bool bps_max_flag, ops_max_flag;
295
296 bps_flag = cfg->buckets[THROTTLE_BPS_TOTAL].avg &&
297 (cfg->buckets[THROTTLE_BPS_READ].avg ||
298 cfg->buckets[THROTTLE_BPS_WRITE].avg);
299
300 ops_flag = cfg->buckets[THROTTLE_OPS_TOTAL].avg &&
301 (cfg->buckets[THROTTLE_OPS_READ].avg ||
302 cfg->buckets[THROTTLE_OPS_WRITE].avg);
303
304 bps_max_flag = cfg->buckets[THROTTLE_BPS_TOTAL].max &&
305 (cfg->buckets[THROTTLE_BPS_READ].max ||
306 cfg->buckets[THROTTLE_BPS_WRITE].max);
307
308 ops_max_flag = cfg->buckets[THROTTLE_OPS_TOTAL].max &&
309 (cfg->buckets[THROTTLE_OPS_READ].max ||
310 cfg->buckets[THROTTLE_OPS_WRITE].max);
311
312 if (bps_flag || ops_flag || bps_max_flag || ops_max_flag) {
313 error_setg(errp, "bps/iops/max total values and read/write values"
314 " cannot be used at the same time");
315 return false;
316 }
317
318 if (cfg->op_size &&
319 !cfg->buckets[THROTTLE_OPS_TOTAL].avg &&
320 !cfg->buckets[THROTTLE_OPS_READ].avg &&
321 !cfg->buckets[THROTTLE_OPS_WRITE].avg) {
322 error_setg(errp, "iops size requires an iops value to be set");
323 return false;
324 }
325
326 for (i = 0; i < BUCKETS_COUNT; i++) {
327 if (cfg->buckets[i].avg < 0 ||
328 cfg->buckets[i].max < 0 ||
329 cfg->buckets[i].avg > THROTTLE_VALUE_MAX ||
330 cfg->buckets[i].max > THROTTLE_VALUE_MAX) {
331 error_setg(errp, "bps/iops/max values must be within [0, %lld]",
332 THROTTLE_VALUE_MAX);
333 return false;
334 }
335
336 if (!cfg->buckets[i].burst_length) {
337 error_setg(errp, "the burst length cannot be 0");
338 return false;
339 }
340
341 if (cfg->buckets[i].burst_length > 1 && !cfg->buckets[i].max) {
342 error_setg(errp, "burst length set without burst rate");
343 return false;
344 }
345
346 if (cfg->buckets[i].max && !cfg->buckets[i].avg) {
347 error_setg(errp, "bps_max/iops_max require corresponding"
348 " bps/iops values");
349 return false;
350 }
351
352 if (cfg->buckets[i].max && cfg->buckets[i].max < cfg->buckets[i].avg) {
353 error_setg(errp, "bps_max/iops_max cannot be lower than bps/iops");
354 return false;
355 }
356 }
357
358 return true;
359}
360
361
362static void throttle_fix_bucket(LeakyBucket *bkt)
363{
364 double min;
365
366
367 bkt->level = bkt->burst_level = 0;
368
369
370
371
372
373
374
375
376
377 min = bkt->avg / 10;
378 if (bkt->avg && !bkt->max) {
379 bkt->max = min;
380 }
381}
382
383
384static void throttle_cancel_timer(QEMUTimer *timer)
385{
386 assert(timer != NULL);
387
388 timer_del(timer);
389}
390
391
392
393
394
395
396
397void throttle_config(ThrottleState *ts,
398 ThrottleTimers *tt,
399 ThrottleConfig *cfg)
400{
401 int i;
402
403 ts->cfg = *cfg;
404
405 for (i = 0; i < BUCKETS_COUNT; i++) {
406 throttle_fix_bucket(&ts->cfg.buckets[i]);
407 }
408
409 ts->previous_leak = qemu_clock_get_ns(tt->clock_type);
410
411 for (i = 0; i < 2; i++) {
412 throttle_cancel_timer(tt->timers[i]);
413 }
414}
415
416
417
418
419
420
421void throttle_get_config(ThrottleState *ts, ThrottleConfig *cfg)
422{
423 *cfg = ts->cfg;
424}
425
426
427
428
429
430
431
432
433
434
435bool throttle_schedule_timer(ThrottleState *ts,
436 ThrottleTimers *tt,
437 bool is_write)
438{
439 int64_t now = qemu_clock_get_ns(tt->clock_type);
440 int64_t next_timestamp;
441 bool must_wait;
442
443 must_wait = throttle_compute_timer(ts,
444 is_write,
445 now,
446 &next_timestamp);
447
448
449 if (!must_wait) {
450 return false;
451 }
452
453
454 if (timer_pending(tt->timers[is_write])) {
455 return true;
456 }
457
458
459 timer_mod(tt->timers[is_write], next_timestamp);
460 return true;
461}
462
463
464
465
466
467
468void throttle_account(ThrottleState *ts, bool is_write, uint64_t size)
469{
470 const BucketType bucket_types_size[2][2] = {
471 { THROTTLE_BPS_TOTAL, THROTTLE_BPS_READ },
472 { THROTTLE_BPS_TOTAL, THROTTLE_BPS_WRITE }
473 };
474 const BucketType bucket_types_units[2][2] = {
475 { THROTTLE_OPS_TOTAL, THROTTLE_OPS_READ },
476 { THROTTLE_OPS_TOTAL, THROTTLE_OPS_WRITE }
477 };
478 double units = 1.0;
479 unsigned i;
480
481
482 if (ts->cfg.op_size && size > ts->cfg.op_size) {
483 units = (double) size / ts->cfg.op_size;
484 }
485
486 for (i = 0; i < 2; i++) {
487 LeakyBucket *bkt;
488
489 bkt = &ts->cfg.buckets[bucket_types_size[is_write][i]];
490 bkt->level += size;
491 if (bkt->burst_length > 1) {
492 bkt->burst_level += size;
493 }
494
495 bkt = &ts->cfg.buckets[bucket_types_units[is_write][i]];
496 bkt->level += units;
497 if (bkt->burst_length > 1) {
498 bkt->burst_level += units;
499 }
500 }
501}
502
503