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Commit | Line | Data |
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e43473b7 VG |
1 | /* |
2 | * Interface for controlling IO bandwidth on a request queue | |
3 | * | |
4 | * Copyright (C) 2010 Vivek Goyal <vgoyal@redhat.com> | |
5 | */ | |
6 | ||
7 | #include <linux/module.h> | |
8 | #include <linux/slab.h> | |
9 | #include <linux/blkdev.h> | |
10 | #include <linux/bio.h> | |
11 | #include <linux/blktrace_api.h> | |
12 | #include "blk-cgroup.h" | |
bc9fcbf9 | 13 | #include "blk.h" |
e43473b7 VG |
14 | |
15 | /* Max dispatch from a group in 1 round */ | |
16 | static int throtl_grp_quantum = 8; | |
17 | ||
18 | /* Total max dispatch from all groups in one round */ | |
19 | static int throtl_quantum = 32; | |
20 | ||
21 | /* Throttling is performed over 100ms slice and after that slice is renewed */ | |
22 | static unsigned long throtl_slice = HZ/10; /* 100 ms */ | |
23 | ||
3c798398 | 24 | static struct blkcg_policy blkcg_policy_throtl; |
0381411e | 25 | |
450adcbe VG |
26 | /* A workqueue to queue throttle related work */ |
27 | static struct workqueue_struct *kthrotld_workqueue; | |
28 | static void throtl_schedule_delayed_work(struct throtl_data *td, | |
29 | unsigned long delay); | |
30 | ||
e43473b7 VG |
31 | struct throtl_rb_root { |
32 | struct rb_root rb; | |
33 | struct rb_node *left; | |
34 | unsigned int count; | |
35 | unsigned long min_disptime; | |
36 | }; | |
37 | ||
38 | #define THROTL_RB_ROOT (struct throtl_rb_root) { .rb = RB_ROOT, .left = NULL, \ | |
39 | .count = 0, .min_disptime = 0} | |
40 | ||
41 | #define rb_entry_tg(node) rb_entry((node), struct throtl_grp, rb_node) | |
42 | ||
8a3d2615 TH |
43 | /* Per-cpu group stats */ |
44 | struct tg_stats_cpu { | |
45 | /* total bytes transferred */ | |
46 | struct blkg_rwstat service_bytes; | |
47 | /* total IOs serviced, post merge */ | |
48 | struct blkg_rwstat serviced; | |
49 | }; | |
50 | ||
e43473b7 | 51 | struct throtl_grp { |
f95a04af TH |
52 | /* must be the first member */ |
53 | struct blkg_policy_data pd; | |
54 | ||
e43473b7 VG |
55 | /* active throtl group service_tree member */ |
56 | struct rb_node rb_node; | |
57 | ||
58 | /* | |
59 | * Dispatch time in jiffies. This is the estimated time when group | |
60 | * will unthrottle and is ready to dispatch more bio. It is used as | |
61 | * key to sort active groups in service tree. | |
62 | */ | |
63 | unsigned long disptime; | |
64 | ||
e43473b7 VG |
65 | unsigned int flags; |
66 | ||
67 | /* Two lists for READ and WRITE */ | |
68 | struct bio_list bio_lists[2]; | |
69 | ||
70 | /* Number of queued bios on READ and WRITE lists */ | |
71 | unsigned int nr_queued[2]; | |
72 | ||
73 | /* bytes per second rate limits */ | |
74 | uint64_t bps[2]; | |
75 | ||
8e89d13f VG |
76 | /* IOPS limits */ |
77 | unsigned int iops[2]; | |
78 | ||
e43473b7 VG |
79 | /* Number of bytes disptached in current slice */ |
80 | uint64_t bytes_disp[2]; | |
8e89d13f VG |
81 | /* Number of bio's dispatched in current slice */ |
82 | unsigned int io_disp[2]; | |
e43473b7 VG |
83 | |
84 | /* When did we start a new slice */ | |
85 | unsigned long slice_start[2]; | |
86 | unsigned long slice_end[2]; | |
fe071437 VG |
87 | |
88 | /* Some throttle limits got updated for the group */ | |
6f037937 | 89 | int limits_changed; |
8a3d2615 TH |
90 | |
91 | /* Per cpu stats pointer */ | |
92 | struct tg_stats_cpu __percpu *stats_cpu; | |
93 | ||
94 | /* List of tgs waiting for per cpu stats memory to be allocated */ | |
95 | struct list_head stats_alloc_node; | |
e43473b7 VG |
96 | }; |
97 | ||
98 | struct throtl_data | |
99 | { | |
e43473b7 VG |
100 | /* service tree for active throtl groups */ |
101 | struct throtl_rb_root tg_service_tree; | |
102 | ||
e43473b7 VG |
103 | struct request_queue *queue; |
104 | ||
105 | /* Total Number of queued bios on READ and WRITE lists */ | |
106 | unsigned int nr_queued[2]; | |
107 | ||
108 | /* | |
02977e4a | 109 | * number of total undestroyed groups |
e43473b7 VG |
110 | */ |
111 | unsigned int nr_undestroyed_grps; | |
112 | ||
113 | /* Work for dispatching throttled bios */ | |
114 | struct delayed_work throtl_work; | |
fe071437 | 115 | |
6f037937 | 116 | int limits_changed; |
e43473b7 VG |
117 | }; |
118 | ||
8a3d2615 TH |
119 | /* list and work item to allocate percpu group stats */ |
120 | static DEFINE_SPINLOCK(tg_stats_alloc_lock); | |
121 | static LIST_HEAD(tg_stats_alloc_list); | |
122 | ||
123 | static void tg_stats_alloc_fn(struct work_struct *); | |
124 | static DECLARE_DELAYED_WORK(tg_stats_alloc_work, tg_stats_alloc_fn); | |
125 | ||
f95a04af TH |
126 | static inline struct throtl_grp *pd_to_tg(struct blkg_policy_data *pd) |
127 | { | |
128 | return pd ? container_of(pd, struct throtl_grp, pd) : NULL; | |
129 | } | |
130 | ||
3c798398 | 131 | static inline struct throtl_grp *blkg_to_tg(struct blkcg_gq *blkg) |
0381411e | 132 | { |
f95a04af | 133 | return pd_to_tg(blkg_to_pd(blkg, &blkcg_policy_throtl)); |
0381411e TH |
134 | } |
135 | ||
3c798398 | 136 | static inline struct blkcg_gq *tg_to_blkg(struct throtl_grp *tg) |
0381411e | 137 | { |
f95a04af | 138 | return pd_to_blkg(&tg->pd); |
0381411e TH |
139 | } |
140 | ||
03d8e111 TH |
141 | static inline struct throtl_grp *td_root_tg(struct throtl_data *td) |
142 | { | |
143 | return blkg_to_tg(td->queue->root_blkg); | |
144 | } | |
145 | ||
e43473b7 VG |
146 | enum tg_state_flags { |
147 | THROTL_TG_FLAG_on_rr = 0, /* on round-robin busy list */ | |
148 | }; | |
149 | ||
150 | #define THROTL_TG_FNS(name) \ | |
151 | static inline void throtl_mark_tg_##name(struct throtl_grp *tg) \ | |
152 | { \ | |
153 | (tg)->flags |= (1 << THROTL_TG_FLAG_##name); \ | |
154 | } \ | |
155 | static inline void throtl_clear_tg_##name(struct throtl_grp *tg) \ | |
156 | { \ | |
157 | (tg)->flags &= ~(1 << THROTL_TG_FLAG_##name); \ | |
158 | } \ | |
159 | static inline int throtl_tg_##name(const struct throtl_grp *tg) \ | |
160 | { \ | |
161 | return ((tg)->flags & (1 << THROTL_TG_FLAG_##name)) != 0; \ | |
162 | } | |
163 | ||
164 | THROTL_TG_FNS(on_rr); | |
165 | ||
54e7ed12 TH |
166 | #define throtl_log_tg(td, tg, fmt, args...) do { \ |
167 | char __pbuf[128]; \ | |
168 | \ | |
169 | blkg_path(tg_to_blkg(tg), __pbuf, sizeof(__pbuf)); \ | |
170 | blk_add_trace_msg((td)->queue, "throtl %s " fmt, __pbuf, ##args); \ | |
171 | } while (0) | |
e43473b7 VG |
172 | |
173 | #define throtl_log(td, fmt, args...) \ | |
174 | blk_add_trace_msg((td)->queue, "throtl " fmt, ##args) | |
175 | ||
d2f31a5f | 176 | static inline unsigned int total_nr_queued(struct throtl_data *td) |
e43473b7 | 177 | { |
d2f31a5f | 178 | return td->nr_queued[0] + td->nr_queued[1]; |
e43473b7 VG |
179 | } |
180 | ||
8a3d2615 TH |
181 | /* |
182 | * Worker for allocating per cpu stat for tgs. This is scheduled on the | |
183 | * system_nrt_wq once there are some groups on the alloc_list waiting for | |
184 | * allocation. | |
185 | */ | |
186 | static void tg_stats_alloc_fn(struct work_struct *work) | |
187 | { | |
188 | static struct tg_stats_cpu *stats_cpu; /* this fn is non-reentrant */ | |
189 | struct delayed_work *dwork = to_delayed_work(work); | |
190 | bool empty = false; | |
191 | ||
192 | alloc_stats: | |
193 | if (!stats_cpu) { | |
194 | stats_cpu = alloc_percpu(struct tg_stats_cpu); | |
195 | if (!stats_cpu) { | |
196 | /* allocation failed, try again after some time */ | |
197 | queue_delayed_work(system_nrt_wq, dwork, | |
198 | msecs_to_jiffies(10)); | |
199 | return; | |
200 | } | |
201 | } | |
202 | ||
203 | spin_lock_irq(&tg_stats_alloc_lock); | |
204 | ||
205 | if (!list_empty(&tg_stats_alloc_list)) { | |
206 | struct throtl_grp *tg = list_first_entry(&tg_stats_alloc_list, | |
207 | struct throtl_grp, | |
208 | stats_alloc_node); | |
209 | swap(tg->stats_cpu, stats_cpu); | |
210 | list_del_init(&tg->stats_alloc_node); | |
211 | } | |
212 | ||
213 | empty = list_empty(&tg_stats_alloc_list); | |
214 | spin_unlock_irq(&tg_stats_alloc_lock); | |
215 | if (!empty) | |
216 | goto alloc_stats; | |
217 | } | |
218 | ||
3c798398 | 219 | static void throtl_pd_init(struct blkcg_gq *blkg) |
a29a171e | 220 | { |
0381411e | 221 | struct throtl_grp *tg = blkg_to_tg(blkg); |
cd1604fa | 222 | |
a29a171e VG |
223 | RB_CLEAR_NODE(&tg->rb_node); |
224 | bio_list_init(&tg->bio_lists[0]); | |
225 | bio_list_init(&tg->bio_lists[1]); | |
226 | tg->limits_changed = false; | |
227 | ||
e56da7e2 TH |
228 | tg->bps[READ] = -1; |
229 | tg->bps[WRITE] = -1; | |
230 | tg->iops[READ] = -1; | |
231 | tg->iops[WRITE] = -1; | |
8a3d2615 TH |
232 | |
233 | /* | |
234 | * Ugh... We need to perform per-cpu allocation for tg->stats_cpu | |
235 | * but percpu allocator can't be called from IO path. Queue tg on | |
236 | * tg_stats_alloc_list and allocate from work item. | |
237 | */ | |
238 | spin_lock(&tg_stats_alloc_lock); | |
239 | list_add(&tg->stats_alloc_node, &tg_stats_alloc_list); | |
240 | queue_delayed_work(system_nrt_wq, &tg_stats_alloc_work, 0); | |
241 | spin_unlock(&tg_stats_alloc_lock); | |
242 | } | |
243 | ||
3c798398 | 244 | static void throtl_pd_exit(struct blkcg_gq *blkg) |
8a3d2615 TH |
245 | { |
246 | struct throtl_grp *tg = blkg_to_tg(blkg); | |
247 | ||
248 | spin_lock(&tg_stats_alloc_lock); | |
249 | list_del_init(&tg->stats_alloc_node); | |
250 | spin_unlock(&tg_stats_alloc_lock); | |
251 | ||
252 | free_percpu(tg->stats_cpu); | |
253 | } | |
254 | ||
3c798398 | 255 | static void throtl_pd_reset_stats(struct blkcg_gq *blkg) |
8a3d2615 TH |
256 | { |
257 | struct throtl_grp *tg = blkg_to_tg(blkg); | |
258 | int cpu; | |
259 | ||
260 | if (tg->stats_cpu == NULL) | |
261 | return; | |
262 | ||
263 | for_each_possible_cpu(cpu) { | |
264 | struct tg_stats_cpu *sc = per_cpu_ptr(tg->stats_cpu, cpu); | |
265 | ||
266 | blkg_rwstat_reset(&sc->service_bytes); | |
267 | blkg_rwstat_reset(&sc->serviced); | |
268 | } | |
a29a171e VG |
269 | } |
270 | ||
3c798398 TH |
271 | static struct throtl_grp *throtl_lookup_tg(struct throtl_data *td, |
272 | struct blkcg *blkcg) | |
e43473b7 | 273 | { |
be2c6b19 | 274 | /* |
3c798398 TH |
275 | * This is the common case when there are no blkcgs. Avoid lookup |
276 | * in this case | |
cd1604fa | 277 | */ |
3c798398 | 278 | if (blkcg == &blkcg_root) |
03d8e111 | 279 | return td_root_tg(td); |
e43473b7 | 280 | |
e8989fae | 281 | return blkg_to_tg(blkg_lookup(blkcg, td->queue)); |
e43473b7 VG |
282 | } |
283 | ||
cd1604fa | 284 | static struct throtl_grp *throtl_lookup_create_tg(struct throtl_data *td, |
3c798398 | 285 | struct blkcg *blkcg) |
e43473b7 | 286 | { |
f469a7b4 | 287 | struct request_queue *q = td->queue; |
cd1604fa | 288 | struct throtl_grp *tg = NULL; |
bc16a4f9 | 289 | |
f469a7b4 | 290 | /* |
3c798398 TH |
291 | * This is the common case when there are no blkcgs. Avoid lookup |
292 | * in this case | |
f469a7b4 | 293 | */ |
3c798398 | 294 | if (blkcg == &blkcg_root) { |
03d8e111 | 295 | tg = td_root_tg(td); |
cd1604fa | 296 | } else { |
3c798398 | 297 | struct blkcg_gq *blkg; |
f469a7b4 | 298 | |
3c96cb32 | 299 | blkg = blkg_lookup_create(blkcg, q); |
f469a7b4 | 300 | |
cd1604fa TH |
301 | /* if %NULL and @q is alive, fall back to root_tg */ |
302 | if (!IS_ERR(blkg)) | |
0381411e | 303 | tg = blkg_to_tg(blkg); |
cd1604fa | 304 | else if (!blk_queue_dead(q)) |
03d8e111 | 305 | tg = td_root_tg(td); |
f469a7b4 VG |
306 | } |
307 | ||
e43473b7 VG |
308 | return tg; |
309 | } | |
310 | ||
311 | static struct throtl_grp *throtl_rb_first(struct throtl_rb_root *root) | |
312 | { | |
313 | /* Service tree is empty */ | |
314 | if (!root->count) | |
315 | return NULL; | |
316 | ||
317 | if (!root->left) | |
318 | root->left = rb_first(&root->rb); | |
319 | ||
320 | if (root->left) | |
321 | return rb_entry_tg(root->left); | |
322 | ||
323 | return NULL; | |
324 | } | |
325 | ||
326 | static void rb_erase_init(struct rb_node *n, struct rb_root *root) | |
327 | { | |
328 | rb_erase(n, root); | |
329 | RB_CLEAR_NODE(n); | |
330 | } | |
331 | ||
332 | static void throtl_rb_erase(struct rb_node *n, struct throtl_rb_root *root) | |
333 | { | |
334 | if (root->left == n) | |
335 | root->left = NULL; | |
336 | rb_erase_init(n, &root->rb); | |
337 | --root->count; | |
338 | } | |
339 | ||
340 | static void update_min_dispatch_time(struct throtl_rb_root *st) | |
341 | { | |
342 | struct throtl_grp *tg; | |
343 | ||
344 | tg = throtl_rb_first(st); | |
345 | if (!tg) | |
346 | return; | |
347 | ||
348 | st->min_disptime = tg->disptime; | |
349 | } | |
350 | ||
351 | static void | |
352 | tg_service_tree_add(struct throtl_rb_root *st, struct throtl_grp *tg) | |
353 | { | |
354 | struct rb_node **node = &st->rb.rb_node; | |
355 | struct rb_node *parent = NULL; | |
356 | struct throtl_grp *__tg; | |
357 | unsigned long key = tg->disptime; | |
358 | int left = 1; | |
359 | ||
360 | while (*node != NULL) { | |
361 | parent = *node; | |
362 | __tg = rb_entry_tg(parent); | |
363 | ||
364 | if (time_before(key, __tg->disptime)) | |
365 | node = &parent->rb_left; | |
366 | else { | |
367 | node = &parent->rb_right; | |
368 | left = 0; | |
369 | } | |
370 | } | |
371 | ||
372 | if (left) | |
373 | st->left = &tg->rb_node; | |
374 | ||
375 | rb_link_node(&tg->rb_node, parent, node); | |
376 | rb_insert_color(&tg->rb_node, &st->rb); | |
377 | } | |
378 | ||
379 | static void __throtl_enqueue_tg(struct throtl_data *td, struct throtl_grp *tg) | |
380 | { | |
381 | struct throtl_rb_root *st = &td->tg_service_tree; | |
382 | ||
383 | tg_service_tree_add(st, tg); | |
384 | throtl_mark_tg_on_rr(tg); | |
385 | st->count++; | |
386 | } | |
387 | ||
388 | static void throtl_enqueue_tg(struct throtl_data *td, struct throtl_grp *tg) | |
389 | { | |
390 | if (!throtl_tg_on_rr(tg)) | |
391 | __throtl_enqueue_tg(td, tg); | |
392 | } | |
393 | ||
394 | static void __throtl_dequeue_tg(struct throtl_data *td, struct throtl_grp *tg) | |
395 | { | |
396 | throtl_rb_erase(&tg->rb_node, &td->tg_service_tree); | |
397 | throtl_clear_tg_on_rr(tg); | |
398 | } | |
399 | ||
400 | static void throtl_dequeue_tg(struct throtl_data *td, struct throtl_grp *tg) | |
401 | { | |
402 | if (throtl_tg_on_rr(tg)) | |
403 | __throtl_dequeue_tg(td, tg); | |
404 | } | |
405 | ||
406 | static void throtl_schedule_next_dispatch(struct throtl_data *td) | |
407 | { | |
408 | struct throtl_rb_root *st = &td->tg_service_tree; | |
409 | ||
410 | /* | |
411 | * If there are more bios pending, schedule more work. | |
412 | */ | |
413 | if (!total_nr_queued(td)) | |
414 | return; | |
415 | ||
416 | BUG_ON(!st->count); | |
417 | ||
418 | update_min_dispatch_time(st); | |
419 | ||
420 | if (time_before_eq(st->min_disptime, jiffies)) | |
450adcbe | 421 | throtl_schedule_delayed_work(td, 0); |
e43473b7 | 422 | else |
450adcbe | 423 | throtl_schedule_delayed_work(td, (st->min_disptime - jiffies)); |
e43473b7 VG |
424 | } |
425 | ||
426 | static inline void | |
427 | throtl_start_new_slice(struct throtl_data *td, struct throtl_grp *tg, bool rw) | |
428 | { | |
429 | tg->bytes_disp[rw] = 0; | |
8e89d13f | 430 | tg->io_disp[rw] = 0; |
e43473b7 VG |
431 | tg->slice_start[rw] = jiffies; |
432 | tg->slice_end[rw] = jiffies + throtl_slice; | |
433 | throtl_log_tg(td, tg, "[%c] new slice start=%lu end=%lu jiffies=%lu", | |
434 | rw == READ ? 'R' : 'W', tg->slice_start[rw], | |
435 | tg->slice_end[rw], jiffies); | |
436 | } | |
437 | ||
d1ae8ffd VG |
438 | static inline void throtl_set_slice_end(struct throtl_data *td, |
439 | struct throtl_grp *tg, bool rw, unsigned long jiffy_end) | |
440 | { | |
441 | tg->slice_end[rw] = roundup(jiffy_end, throtl_slice); | |
442 | } | |
443 | ||
e43473b7 VG |
444 | static inline void throtl_extend_slice(struct throtl_data *td, |
445 | struct throtl_grp *tg, bool rw, unsigned long jiffy_end) | |
446 | { | |
447 | tg->slice_end[rw] = roundup(jiffy_end, throtl_slice); | |
448 | throtl_log_tg(td, tg, "[%c] extend slice start=%lu end=%lu jiffies=%lu", | |
449 | rw == READ ? 'R' : 'W', tg->slice_start[rw], | |
450 | tg->slice_end[rw], jiffies); | |
451 | } | |
452 | ||
453 | /* Determine if previously allocated or extended slice is complete or not */ | |
454 | static bool | |
455 | throtl_slice_used(struct throtl_data *td, struct throtl_grp *tg, bool rw) | |
456 | { | |
457 | if (time_in_range(jiffies, tg->slice_start[rw], tg->slice_end[rw])) | |
458 | return 0; | |
459 | ||
460 | return 1; | |
461 | } | |
462 | ||
463 | /* Trim the used slices and adjust slice start accordingly */ | |
464 | static inline void | |
465 | throtl_trim_slice(struct throtl_data *td, struct throtl_grp *tg, bool rw) | |
466 | { | |
3aad5d3e VG |
467 | unsigned long nr_slices, time_elapsed, io_trim; |
468 | u64 bytes_trim, tmp; | |
e43473b7 VG |
469 | |
470 | BUG_ON(time_before(tg->slice_end[rw], tg->slice_start[rw])); | |
471 | ||
472 | /* | |
473 | * If bps are unlimited (-1), then time slice don't get | |
474 | * renewed. Don't try to trim the slice if slice is used. A new | |
475 | * slice will start when appropriate. | |
476 | */ | |
477 | if (throtl_slice_used(td, tg, rw)) | |
478 | return; | |
479 | ||
d1ae8ffd VG |
480 | /* |
481 | * A bio has been dispatched. Also adjust slice_end. It might happen | |
482 | * that initially cgroup limit was very low resulting in high | |
483 | * slice_end, but later limit was bumped up and bio was dispached | |
484 | * sooner, then we need to reduce slice_end. A high bogus slice_end | |
485 | * is bad because it does not allow new slice to start. | |
486 | */ | |
487 | ||
488 | throtl_set_slice_end(td, tg, rw, jiffies + throtl_slice); | |
489 | ||
e43473b7 VG |
490 | time_elapsed = jiffies - tg->slice_start[rw]; |
491 | ||
492 | nr_slices = time_elapsed / throtl_slice; | |
493 | ||
494 | if (!nr_slices) | |
495 | return; | |
3aad5d3e VG |
496 | tmp = tg->bps[rw] * throtl_slice * nr_slices; |
497 | do_div(tmp, HZ); | |
498 | bytes_trim = tmp; | |
e43473b7 | 499 | |
8e89d13f | 500 | io_trim = (tg->iops[rw] * throtl_slice * nr_slices)/HZ; |
e43473b7 | 501 | |
8e89d13f | 502 | if (!bytes_trim && !io_trim) |
e43473b7 VG |
503 | return; |
504 | ||
505 | if (tg->bytes_disp[rw] >= bytes_trim) | |
506 | tg->bytes_disp[rw] -= bytes_trim; | |
507 | else | |
508 | tg->bytes_disp[rw] = 0; | |
509 | ||
8e89d13f VG |
510 | if (tg->io_disp[rw] >= io_trim) |
511 | tg->io_disp[rw] -= io_trim; | |
512 | else | |
513 | tg->io_disp[rw] = 0; | |
514 | ||
e43473b7 VG |
515 | tg->slice_start[rw] += nr_slices * throtl_slice; |
516 | ||
3aad5d3e | 517 | throtl_log_tg(td, tg, "[%c] trim slice nr=%lu bytes=%llu io=%lu" |
e43473b7 | 518 | " start=%lu end=%lu jiffies=%lu", |
8e89d13f | 519 | rw == READ ? 'R' : 'W', nr_slices, bytes_trim, io_trim, |
e43473b7 VG |
520 | tg->slice_start[rw], tg->slice_end[rw], jiffies); |
521 | } | |
522 | ||
8e89d13f VG |
523 | static bool tg_with_in_iops_limit(struct throtl_data *td, struct throtl_grp *tg, |
524 | struct bio *bio, unsigned long *wait) | |
e43473b7 VG |
525 | { |
526 | bool rw = bio_data_dir(bio); | |
8e89d13f | 527 | unsigned int io_allowed; |
e43473b7 | 528 | unsigned long jiffy_elapsed, jiffy_wait, jiffy_elapsed_rnd; |
c49c06e4 | 529 | u64 tmp; |
e43473b7 | 530 | |
8e89d13f | 531 | jiffy_elapsed = jiffy_elapsed_rnd = jiffies - tg->slice_start[rw]; |
e43473b7 | 532 | |
8e89d13f VG |
533 | /* Slice has just started. Consider one slice interval */ |
534 | if (!jiffy_elapsed) | |
535 | jiffy_elapsed_rnd = throtl_slice; | |
536 | ||
537 | jiffy_elapsed_rnd = roundup(jiffy_elapsed_rnd, throtl_slice); | |
538 | ||
c49c06e4 VG |
539 | /* |
540 | * jiffy_elapsed_rnd should not be a big value as minimum iops can be | |
541 | * 1 then at max jiffy elapsed should be equivalent of 1 second as we | |
542 | * will allow dispatch after 1 second and after that slice should | |
543 | * have been trimmed. | |
544 | */ | |
545 | ||
546 | tmp = (u64)tg->iops[rw] * jiffy_elapsed_rnd; | |
547 | do_div(tmp, HZ); | |
548 | ||
549 | if (tmp > UINT_MAX) | |
550 | io_allowed = UINT_MAX; | |
551 | else | |
552 | io_allowed = tmp; | |
8e89d13f VG |
553 | |
554 | if (tg->io_disp[rw] + 1 <= io_allowed) { | |
e43473b7 VG |
555 | if (wait) |
556 | *wait = 0; | |
557 | return 1; | |
558 | } | |
559 | ||
8e89d13f VG |
560 | /* Calc approx time to dispatch */ |
561 | jiffy_wait = ((tg->io_disp[rw] + 1) * HZ)/tg->iops[rw] + 1; | |
562 | ||
563 | if (jiffy_wait > jiffy_elapsed) | |
564 | jiffy_wait = jiffy_wait - jiffy_elapsed; | |
565 | else | |
566 | jiffy_wait = 1; | |
567 | ||
568 | if (wait) | |
569 | *wait = jiffy_wait; | |
570 | return 0; | |
571 | } | |
572 | ||
573 | static bool tg_with_in_bps_limit(struct throtl_data *td, struct throtl_grp *tg, | |
574 | struct bio *bio, unsigned long *wait) | |
575 | { | |
576 | bool rw = bio_data_dir(bio); | |
3aad5d3e | 577 | u64 bytes_allowed, extra_bytes, tmp; |
8e89d13f | 578 | unsigned long jiffy_elapsed, jiffy_wait, jiffy_elapsed_rnd; |
e43473b7 VG |
579 | |
580 | jiffy_elapsed = jiffy_elapsed_rnd = jiffies - tg->slice_start[rw]; | |
581 | ||
582 | /* Slice has just started. Consider one slice interval */ | |
583 | if (!jiffy_elapsed) | |
584 | jiffy_elapsed_rnd = throtl_slice; | |
585 | ||
586 | jiffy_elapsed_rnd = roundup(jiffy_elapsed_rnd, throtl_slice); | |
587 | ||
5e901a2b VG |
588 | tmp = tg->bps[rw] * jiffy_elapsed_rnd; |
589 | do_div(tmp, HZ); | |
3aad5d3e | 590 | bytes_allowed = tmp; |
e43473b7 VG |
591 | |
592 | if (tg->bytes_disp[rw] + bio->bi_size <= bytes_allowed) { | |
593 | if (wait) | |
594 | *wait = 0; | |
595 | return 1; | |
596 | } | |
597 | ||
598 | /* Calc approx time to dispatch */ | |
599 | extra_bytes = tg->bytes_disp[rw] + bio->bi_size - bytes_allowed; | |
600 | jiffy_wait = div64_u64(extra_bytes * HZ, tg->bps[rw]); | |
601 | ||
602 | if (!jiffy_wait) | |
603 | jiffy_wait = 1; | |
604 | ||
605 | /* | |
606 | * This wait time is without taking into consideration the rounding | |
607 | * up we did. Add that time also. | |
608 | */ | |
609 | jiffy_wait = jiffy_wait + (jiffy_elapsed_rnd - jiffy_elapsed); | |
e43473b7 VG |
610 | if (wait) |
611 | *wait = jiffy_wait; | |
8e89d13f VG |
612 | return 0; |
613 | } | |
614 | ||
af75cd3c VG |
615 | static bool tg_no_rule_group(struct throtl_grp *tg, bool rw) { |
616 | if (tg->bps[rw] == -1 && tg->iops[rw] == -1) | |
617 | return 1; | |
618 | return 0; | |
619 | } | |
620 | ||
8e89d13f VG |
621 | /* |
622 | * Returns whether one can dispatch a bio or not. Also returns approx number | |
623 | * of jiffies to wait before this bio is with-in IO rate and can be dispatched | |
624 | */ | |
625 | static bool tg_may_dispatch(struct throtl_data *td, struct throtl_grp *tg, | |
626 | struct bio *bio, unsigned long *wait) | |
627 | { | |
628 | bool rw = bio_data_dir(bio); | |
629 | unsigned long bps_wait = 0, iops_wait = 0, max_wait = 0; | |
630 | ||
631 | /* | |
632 | * Currently whole state machine of group depends on first bio | |
633 | * queued in the group bio list. So one should not be calling | |
634 | * this function with a different bio if there are other bios | |
635 | * queued. | |
636 | */ | |
637 | BUG_ON(tg->nr_queued[rw] && bio != bio_list_peek(&tg->bio_lists[rw])); | |
e43473b7 | 638 | |
8e89d13f VG |
639 | /* If tg->bps = -1, then BW is unlimited */ |
640 | if (tg->bps[rw] == -1 && tg->iops[rw] == -1) { | |
641 | if (wait) | |
642 | *wait = 0; | |
643 | return 1; | |
644 | } | |
645 | ||
646 | /* | |
647 | * If previous slice expired, start a new one otherwise renew/extend | |
648 | * existing slice to make sure it is at least throtl_slice interval | |
649 | * long since now. | |
650 | */ | |
651 | if (throtl_slice_used(td, tg, rw)) | |
652 | throtl_start_new_slice(td, tg, rw); | |
653 | else { | |
654 | if (time_before(tg->slice_end[rw], jiffies + throtl_slice)) | |
655 | throtl_extend_slice(td, tg, rw, jiffies + throtl_slice); | |
656 | } | |
657 | ||
658 | if (tg_with_in_bps_limit(td, tg, bio, &bps_wait) | |
659 | && tg_with_in_iops_limit(td, tg, bio, &iops_wait)) { | |
660 | if (wait) | |
661 | *wait = 0; | |
662 | return 1; | |
663 | } | |
664 | ||
665 | max_wait = max(bps_wait, iops_wait); | |
666 | ||
667 | if (wait) | |
668 | *wait = max_wait; | |
669 | ||
670 | if (time_before(tg->slice_end[rw], jiffies + max_wait)) | |
671 | throtl_extend_slice(td, tg, rw, jiffies + max_wait); | |
e43473b7 VG |
672 | |
673 | return 0; | |
674 | } | |
675 | ||
3c798398 | 676 | static void throtl_update_dispatch_stats(struct blkcg_gq *blkg, u64 bytes, |
629ed0b1 TH |
677 | int rw) |
678 | { | |
8a3d2615 TH |
679 | struct throtl_grp *tg = blkg_to_tg(blkg); |
680 | struct tg_stats_cpu *stats_cpu; | |
629ed0b1 TH |
681 | unsigned long flags; |
682 | ||
683 | /* If per cpu stats are not allocated yet, don't do any accounting. */ | |
8a3d2615 | 684 | if (tg->stats_cpu == NULL) |
629ed0b1 TH |
685 | return; |
686 | ||
687 | /* | |
688 | * Disabling interrupts to provide mutual exclusion between two | |
689 | * writes on same cpu. It probably is not needed for 64bit. Not | |
690 | * optimizing that case yet. | |
691 | */ | |
692 | local_irq_save(flags); | |
693 | ||
8a3d2615 | 694 | stats_cpu = this_cpu_ptr(tg->stats_cpu); |
629ed0b1 | 695 | |
629ed0b1 TH |
696 | blkg_rwstat_add(&stats_cpu->serviced, rw, 1); |
697 | blkg_rwstat_add(&stats_cpu->service_bytes, rw, bytes); | |
698 | ||
699 | local_irq_restore(flags); | |
700 | } | |
701 | ||
e43473b7 VG |
702 | static void throtl_charge_bio(struct throtl_grp *tg, struct bio *bio) |
703 | { | |
704 | bool rw = bio_data_dir(bio); | |
e43473b7 VG |
705 | |
706 | /* Charge the bio to the group */ | |
707 | tg->bytes_disp[rw] += bio->bi_size; | |
8e89d13f | 708 | tg->io_disp[rw]++; |
e43473b7 | 709 | |
629ed0b1 | 710 | throtl_update_dispatch_stats(tg_to_blkg(tg), bio->bi_size, bio->bi_rw); |
e43473b7 VG |
711 | } |
712 | ||
713 | static void throtl_add_bio_tg(struct throtl_data *td, struct throtl_grp *tg, | |
714 | struct bio *bio) | |
715 | { | |
716 | bool rw = bio_data_dir(bio); | |
717 | ||
718 | bio_list_add(&tg->bio_lists[rw], bio); | |
719 | /* Take a bio reference on tg */ | |
1adaf3dd | 720 | blkg_get(tg_to_blkg(tg)); |
e43473b7 VG |
721 | tg->nr_queued[rw]++; |
722 | td->nr_queued[rw]++; | |
723 | throtl_enqueue_tg(td, tg); | |
724 | } | |
725 | ||
726 | static void tg_update_disptime(struct throtl_data *td, struct throtl_grp *tg) | |
727 | { | |
728 | unsigned long read_wait = -1, write_wait = -1, min_wait = -1, disptime; | |
729 | struct bio *bio; | |
730 | ||
731 | if ((bio = bio_list_peek(&tg->bio_lists[READ]))) | |
732 | tg_may_dispatch(td, tg, bio, &read_wait); | |
733 | ||
734 | if ((bio = bio_list_peek(&tg->bio_lists[WRITE]))) | |
735 | tg_may_dispatch(td, tg, bio, &write_wait); | |
736 | ||
737 | min_wait = min(read_wait, write_wait); | |
738 | disptime = jiffies + min_wait; | |
739 | ||
e43473b7 VG |
740 | /* Update dispatch time */ |
741 | throtl_dequeue_tg(td, tg); | |
742 | tg->disptime = disptime; | |
743 | throtl_enqueue_tg(td, tg); | |
744 | } | |
745 | ||
746 | static void tg_dispatch_one_bio(struct throtl_data *td, struct throtl_grp *tg, | |
747 | bool rw, struct bio_list *bl) | |
748 | { | |
749 | struct bio *bio; | |
750 | ||
751 | bio = bio_list_pop(&tg->bio_lists[rw]); | |
752 | tg->nr_queued[rw]--; | |
1adaf3dd TH |
753 | /* Drop bio reference on blkg */ |
754 | blkg_put(tg_to_blkg(tg)); | |
e43473b7 VG |
755 | |
756 | BUG_ON(td->nr_queued[rw] <= 0); | |
757 | td->nr_queued[rw]--; | |
758 | ||
759 | throtl_charge_bio(tg, bio); | |
760 | bio_list_add(bl, bio); | |
761 | bio->bi_rw |= REQ_THROTTLED; | |
762 | ||
763 | throtl_trim_slice(td, tg, rw); | |
764 | } | |
765 | ||
766 | static int throtl_dispatch_tg(struct throtl_data *td, struct throtl_grp *tg, | |
767 | struct bio_list *bl) | |
768 | { | |
769 | unsigned int nr_reads = 0, nr_writes = 0; | |
770 | unsigned int max_nr_reads = throtl_grp_quantum*3/4; | |
c2f6805d | 771 | unsigned int max_nr_writes = throtl_grp_quantum - max_nr_reads; |
e43473b7 VG |
772 | struct bio *bio; |
773 | ||
774 | /* Try to dispatch 75% READS and 25% WRITES */ | |
775 | ||
776 | while ((bio = bio_list_peek(&tg->bio_lists[READ])) | |
777 | && tg_may_dispatch(td, tg, bio, NULL)) { | |
778 | ||
779 | tg_dispatch_one_bio(td, tg, bio_data_dir(bio), bl); | |
780 | nr_reads++; | |
781 | ||
782 | if (nr_reads >= max_nr_reads) | |
783 | break; | |
784 | } | |
785 | ||
786 | while ((bio = bio_list_peek(&tg->bio_lists[WRITE])) | |
787 | && tg_may_dispatch(td, tg, bio, NULL)) { | |
788 | ||
789 | tg_dispatch_one_bio(td, tg, bio_data_dir(bio), bl); | |
790 | nr_writes++; | |
791 | ||
792 | if (nr_writes >= max_nr_writes) | |
793 | break; | |
794 | } | |
795 | ||
796 | return nr_reads + nr_writes; | |
797 | } | |
798 | ||
799 | static int throtl_select_dispatch(struct throtl_data *td, struct bio_list *bl) | |
800 | { | |
801 | unsigned int nr_disp = 0; | |
802 | struct throtl_grp *tg; | |
803 | struct throtl_rb_root *st = &td->tg_service_tree; | |
804 | ||
805 | while (1) { | |
806 | tg = throtl_rb_first(st); | |
807 | ||
808 | if (!tg) | |
809 | break; | |
810 | ||
811 | if (time_before(jiffies, tg->disptime)) | |
812 | break; | |
813 | ||
814 | throtl_dequeue_tg(td, tg); | |
815 | ||
816 | nr_disp += throtl_dispatch_tg(td, tg, bl); | |
817 | ||
818 | if (tg->nr_queued[0] || tg->nr_queued[1]) { | |
819 | tg_update_disptime(td, tg); | |
820 | throtl_enqueue_tg(td, tg); | |
821 | } | |
822 | ||
823 | if (nr_disp >= throtl_quantum) | |
824 | break; | |
825 | } | |
826 | ||
827 | return nr_disp; | |
828 | } | |
829 | ||
fe071437 VG |
830 | static void throtl_process_limit_change(struct throtl_data *td) |
831 | { | |
4eef3049 | 832 | struct request_queue *q = td->queue; |
3c798398 | 833 | struct blkcg_gq *blkg, *n; |
fe071437 | 834 | |
de701c74 | 835 | if (!td->limits_changed) |
fe071437 VG |
836 | return; |
837 | ||
de701c74 | 838 | xchg(&td->limits_changed, false); |
fe071437 | 839 | |
de701c74 | 840 | throtl_log(td, "limits changed"); |
fe071437 | 841 | |
e8989fae | 842 | list_for_each_entry_safe(blkg, n, &q->blkg_list, q_node) { |
4eef3049 TH |
843 | struct throtl_grp *tg = blkg_to_tg(blkg); |
844 | ||
de701c74 VG |
845 | if (!tg->limits_changed) |
846 | continue; | |
847 | ||
848 | if (!xchg(&tg->limits_changed, false)) | |
849 | continue; | |
850 | ||
851 | throtl_log_tg(td, tg, "limit change rbps=%llu wbps=%llu" | |
852 | " riops=%u wiops=%u", tg->bps[READ], tg->bps[WRITE], | |
853 | tg->iops[READ], tg->iops[WRITE]); | |
854 | ||
04521db0 VG |
855 | /* |
856 | * Restart the slices for both READ and WRITES. It | |
857 | * might happen that a group's limit are dropped | |
858 | * suddenly and we don't want to account recently | |
859 | * dispatched IO with new low rate | |
860 | */ | |
861 | throtl_start_new_slice(td, tg, 0); | |
862 | throtl_start_new_slice(td, tg, 1); | |
863 | ||
de701c74 | 864 | if (throtl_tg_on_rr(tg)) |
fe071437 | 865 | tg_update_disptime(td, tg); |
fe071437 | 866 | } |
fe071437 VG |
867 | } |
868 | ||
e43473b7 VG |
869 | /* Dispatch throttled bios. Should be called without queue lock held. */ |
870 | static int throtl_dispatch(struct request_queue *q) | |
871 | { | |
872 | struct throtl_data *td = q->td; | |
873 | unsigned int nr_disp = 0; | |
874 | struct bio_list bio_list_on_stack; | |
875 | struct bio *bio; | |
69d60eb9 | 876 | struct blk_plug plug; |
e43473b7 VG |
877 | |
878 | spin_lock_irq(q->queue_lock); | |
879 | ||
fe071437 VG |
880 | throtl_process_limit_change(td); |
881 | ||
e43473b7 VG |
882 | if (!total_nr_queued(td)) |
883 | goto out; | |
884 | ||
885 | bio_list_init(&bio_list_on_stack); | |
886 | ||
d2f31a5f | 887 | throtl_log(td, "dispatch nr_queued=%u read=%u write=%u", |
e43473b7 VG |
888 | total_nr_queued(td), td->nr_queued[READ], |
889 | td->nr_queued[WRITE]); | |
890 | ||
891 | nr_disp = throtl_select_dispatch(td, &bio_list_on_stack); | |
892 | ||
893 | if (nr_disp) | |
894 | throtl_log(td, "bios disp=%u", nr_disp); | |
895 | ||
896 | throtl_schedule_next_dispatch(td); | |
897 | out: | |
898 | spin_unlock_irq(q->queue_lock); | |
899 | ||
900 | /* | |
901 | * If we dispatched some requests, unplug the queue to make sure | |
902 | * immediate dispatch | |
903 | */ | |
904 | if (nr_disp) { | |
69d60eb9 | 905 | blk_start_plug(&plug); |
e43473b7 VG |
906 | while((bio = bio_list_pop(&bio_list_on_stack))) |
907 | generic_make_request(bio); | |
69d60eb9 | 908 | blk_finish_plug(&plug); |
e43473b7 VG |
909 | } |
910 | return nr_disp; | |
911 | } | |
912 | ||
913 | void blk_throtl_work(struct work_struct *work) | |
914 | { | |
915 | struct throtl_data *td = container_of(work, struct throtl_data, | |
916 | throtl_work.work); | |
917 | struct request_queue *q = td->queue; | |
918 | ||
919 | throtl_dispatch(q); | |
920 | } | |
921 | ||
922 | /* Call with queue lock held */ | |
450adcbe VG |
923 | static void |
924 | throtl_schedule_delayed_work(struct throtl_data *td, unsigned long delay) | |
e43473b7 VG |
925 | { |
926 | ||
e43473b7 VG |
927 | struct delayed_work *dwork = &td->throtl_work; |
928 | ||
04521db0 | 929 | /* schedule work if limits changed even if no bio is queued */ |
d2f31a5f | 930 | if (total_nr_queued(td) || td->limits_changed) { |
e43473b7 VG |
931 | /* |
932 | * We might have a work scheduled to be executed in future. | |
933 | * Cancel that and schedule a new one. | |
934 | */ | |
935 | __cancel_delayed_work(dwork); | |
450adcbe | 936 | queue_delayed_work(kthrotld_workqueue, dwork, delay); |
e43473b7 VG |
937 | throtl_log(td, "schedule work. delay=%lu jiffies=%lu", |
938 | delay, jiffies); | |
939 | } | |
940 | } | |
e43473b7 | 941 | |
f95a04af TH |
942 | static u64 tg_prfill_cpu_rwstat(struct seq_file *sf, |
943 | struct blkg_policy_data *pd, int off) | |
41b38b6d | 944 | { |
f95a04af | 945 | struct throtl_grp *tg = pd_to_tg(pd); |
41b38b6d TH |
946 | struct blkg_rwstat rwstat = { }, tmp; |
947 | int i, cpu; | |
948 | ||
949 | for_each_possible_cpu(cpu) { | |
8a3d2615 | 950 | struct tg_stats_cpu *sc = per_cpu_ptr(tg->stats_cpu, cpu); |
41b38b6d TH |
951 | |
952 | tmp = blkg_rwstat_read((void *)sc + off); | |
953 | for (i = 0; i < BLKG_RWSTAT_NR; i++) | |
954 | rwstat.cnt[i] += tmp.cnt[i]; | |
955 | } | |
956 | ||
f95a04af | 957 | return __blkg_prfill_rwstat(sf, pd, &rwstat); |
41b38b6d TH |
958 | } |
959 | ||
8a3d2615 TH |
960 | static int tg_print_cpu_rwstat(struct cgroup *cgrp, struct cftype *cft, |
961 | struct seq_file *sf) | |
41b38b6d | 962 | { |
3c798398 | 963 | struct blkcg *blkcg = cgroup_to_blkcg(cgrp); |
41b38b6d | 964 | |
3c798398 | 965 | blkcg_print_blkgs(sf, blkcg, tg_prfill_cpu_rwstat, &blkcg_policy_throtl, |
5bc4afb1 | 966 | cft->private, true); |
41b38b6d TH |
967 | return 0; |
968 | } | |
969 | ||
f95a04af TH |
970 | static u64 tg_prfill_conf_u64(struct seq_file *sf, struct blkg_policy_data *pd, |
971 | int off) | |
60c2bc2d | 972 | { |
f95a04af TH |
973 | struct throtl_grp *tg = pd_to_tg(pd); |
974 | u64 v = *(u64 *)((void *)tg + off); | |
60c2bc2d | 975 | |
af133ceb | 976 | if (v == -1) |
60c2bc2d | 977 | return 0; |
f95a04af | 978 | return __blkg_prfill_u64(sf, pd, v); |
60c2bc2d TH |
979 | } |
980 | ||
f95a04af TH |
981 | static u64 tg_prfill_conf_uint(struct seq_file *sf, struct blkg_policy_data *pd, |
982 | int off) | |
e43473b7 | 983 | { |
f95a04af TH |
984 | struct throtl_grp *tg = pd_to_tg(pd); |
985 | unsigned int v = *(unsigned int *)((void *)tg + off); | |
fe071437 | 986 | |
af133ceb TH |
987 | if (v == -1) |
988 | return 0; | |
f95a04af | 989 | return __blkg_prfill_u64(sf, pd, v); |
e43473b7 VG |
990 | } |
991 | ||
af133ceb TH |
992 | static int tg_print_conf_u64(struct cgroup *cgrp, struct cftype *cft, |
993 | struct seq_file *sf) | |
8e89d13f | 994 | { |
3c798398 TH |
995 | blkcg_print_blkgs(sf, cgroup_to_blkcg(cgrp), tg_prfill_conf_u64, |
996 | &blkcg_policy_throtl, cft->private, false); | |
af133ceb | 997 | return 0; |
8e89d13f VG |
998 | } |
999 | ||
af133ceb TH |
1000 | static int tg_print_conf_uint(struct cgroup *cgrp, struct cftype *cft, |
1001 | struct seq_file *sf) | |
8e89d13f | 1002 | { |
3c798398 TH |
1003 | blkcg_print_blkgs(sf, cgroup_to_blkcg(cgrp), tg_prfill_conf_uint, |
1004 | &blkcg_policy_throtl, cft->private, false); | |
af133ceb | 1005 | return 0; |
60c2bc2d TH |
1006 | } |
1007 | ||
af133ceb TH |
1008 | static int tg_set_conf(struct cgroup *cgrp, struct cftype *cft, const char *buf, |
1009 | bool is_u64) | |
60c2bc2d | 1010 | { |
3c798398 | 1011 | struct blkcg *blkcg = cgroup_to_blkcg(cgrp); |
60c2bc2d | 1012 | struct blkg_conf_ctx ctx; |
af133ceb | 1013 | struct throtl_grp *tg; |
a2b1693b | 1014 | struct throtl_data *td; |
60c2bc2d TH |
1015 | int ret; |
1016 | ||
3c798398 | 1017 | ret = blkg_conf_prep(blkcg, &blkcg_policy_throtl, buf, &ctx); |
60c2bc2d TH |
1018 | if (ret) |
1019 | return ret; | |
1020 | ||
af133ceb | 1021 | tg = blkg_to_tg(ctx.blkg); |
a2b1693b | 1022 | td = ctx.blkg->q->td; |
af133ceb | 1023 | |
a2b1693b TH |
1024 | if (!ctx.v) |
1025 | ctx.v = -1; | |
af133ceb | 1026 | |
a2b1693b TH |
1027 | if (is_u64) |
1028 | *(u64 *)((void *)tg + cft->private) = ctx.v; | |
1029 | else | |
1030 | *(unsigned int *)((void *)tg + cft->private) = ctx.v; | |
af133ceb | 1031 | |
a2b1693b TH |
1032 | /* XXX: we don't need the following deferred processing */ |
1033 | xchg(&tg->limits_changed, true); | |
1034 | xchg(&td->limits_changed, true); | |
1035 | throtl_schedule_delayed_work(td, 0); | |
60c2bc2d TH |
1036 | |
1037 | blkg_conf_finish(&ctx); | |
a2b1693b | 1038 | return 0; |
8e89d13f VG |
1039 | } |
1040 | ||
af133ceb TH |
1041 | static int tg_set_conf_u64(struct cgroup *cgrp, struct cftype *cft, |
1042 | const char *buf) | |
60c2bc2d | 1043 | { |
af133ceb | 1044 | return tg_set_conf(cgrp, cft, buf, true); |
60c2bc2d TH |
1045 | } |
1046 | ||
af133ceb TH |
1047 | static int tg_set_conf_uint(struct cgroup *cgrp, struct cftype *cft, |
1048 | const char *buf) | |
60c2bc2d | 1049 | { |
af133ceb | 1050 | return tg_set_conf(cgrp, cft, buf, false); |
60c2bc2d TH |
1051 | } |
1052 | ||
1053 | static struct cftype throtl_files[] = { | |
1054 | { | |
1055 | .name = "throttle.read_bps_device", | |
af133ceb TH |
1056 | .private = offsetof(struct throtl_grp, bps[READ]), |
1057 | .read_seq_string = tg_print_conf_u64, | |
1058 | .write_string = tg_set_conf_u64, | |
60c2bc2d TH |
1059 | .max_write_len = 256, |
1060 | }, | |
1061 | { | |
1062 | .name = "throttle.write_bps_device", | |
af133ceb TH |
1063 | .private = offsetof(struct throtl_grp, bps[WRITE]), |
1064 | .read_seq_string = tg_print_conf_u64, | |
1065 | .write_string = tg_set_conf_u64, | |
60c2bc2d TH |
1066 | .max_write_len = 256, |
1067 | }, | |
1068 | { | |
1069 | .name = "throttle.read_iops_device", | |
af133ceb TH |
1070 | .private = offsetof(struct throtl_grp, iops[READ]), |
1071 | .read_seq_string = tg_print_conf_uint, | |
1072 | .write_string = tg_set_conf_uint, | |
60c2bc2d TH |
1073 | .max_write_len = 256, |
1074 | }, | |
1075 | { | |
1076 | .name = "throttle.write_iops_device", | |
af133ceb TH |
1077 | .private = offsetof(struct throtl_grp, iops[WRITE]), |
1078 | .read_seq_string = tg_print_conf_uint, | |
1079 | .write_string = tg_set_conf_uint, | |
60c2bc2d TH |
1080 | .max_write_len = 256, |
1081 | }, | |
1082 | { | |
1083 | .name = "throttle.io_service_bytes", | |
5bc4afb1 | 1084 | .private = offsetof(struct tg_stats_cpu, service_bytes), |
8a3d2615 | 1085 | .read_seq_string = tg_print_cpu_rwstat, |
60c2bc2d TH |
1086 | }, |
1087 | { | |
1088 | .name = "throttle.io_serviced", | |
5bc4afb1 | 1089 | .private = offsetof(struct tg_stats_cpu, serviced), |
8a3d2615 | 1090 | .read_seq_string = tg_print_cpu_rwstat, |
60c2bc2d TH |
1091 | }, |
1092 | { } /* terminate */ | |
1093 | }; | |
1094 | ||
da527770 | 1095 | static void throtl_shutdown_wq(struct request_queue *q) |
e43473b7 VG |
1096 | { |
1097 | struct throtl_data *td = q->td; | |
1098 | ||
1099 | cancel_delayed_work_sync(&td->throtl_work); | |
1100 | } | |
1101 | ||
3c798398 | 1102 | static struct blkcg_policy blkcg_policy_throtl = { |
e43473b7 | 1103 | .ops = { |
3c798398 TH |
1104 | .pd_init_fn = throtl_pd_init, |
1105 | .pd_exit_fn = throtl_pd_exit, | |
1106 | .pd_reset_stats_fn = throtl_pd_reset_stats, | |
e43473b7 | 1107 | }, |
f95a04af | 1108 | .pd_size = sizeof(struct throtl_grp), |
60c2bc2d | 1109 | .cftypes = throtl_files, |
e43473b7 VG |
1110 | }; |
1111 | ||
bc16a4f9 | 1112 | bool blk_throtl_bio(struct request_queue *q, struct bio *bio) |
e43473b7 VG |
1113 | { |
1114 | struct throtl_data *td = q->td; | |
1115 | struct throtl_grp *tg; | |
e43473b7 | 1116 | bool rw = bio_data_dir(bio), update_disptime = true; |
3c798398 | 1117 | struct blkcg *blkcg; |
bc16a4f9 | 1118 | bool throttled = false; |
e43473b7 VG |
1119 | |
1120 | if (bio->bi_rw & REQ_THROTTLED) { | |
1121 | bio->bi_rw &= ~REQ_THROTTLED; | |
bc16a4f9 | 1122 | goto out; |
e43473b7 VG |
1123 | } |
1124 | ||
671058fb TH |
1125 | /* bio_associate_current() needs ioc, try creating */ |
1126 | create_io_context(GFP_ATOMIC, q->node); | |
1127 | ||
af75cd3c VG |
1128 | /* |
1129 | * A throtl_grp pointer retrieved under rcu can be used to access | |
1130 | * basic fields like stats and io rates. If a group has no rules, | |
1131 | * just update the dispatch stats in lockless manner and return. | |
1132 | */ | |
af75cd3c | 1133 | rcu_read_lock(); |
3c798398 | 1134 | blkcg = bio_blkcg(bio); |
cd1604fa | 1135 | tg = throtl_lookup_tg(td, blkcg); |
af75cd3c | 1136 | if (tg) { |
af75cd3c | 1137 | if (tg_no_rule_group(tg, rw)) { |
629ed0b1 TH |
1138 | throtl_update_dispatch_stats(tg_to_blkg(tg), |
1139 | bio->bi_size, bio->bi_rw); | |
2a7f1244 | 1140 | goto out_unlock_rcu; |
af75cd3c VG |
1141 | } |
1142 | } | |
af75cd3c VG |
1143 | |
1144 | /* | |
1145 | * Either group has not been allocated yet or it is not an unlimited | |
1146 | * IO group | |
1147 | */ | |
e43473b7 | 1148 | spin_lock_irq(q->queue_lock); |
cd1604fa | 1149 | tg = throtl_lookup_create_tg(td, blkcg); |
bc16a4f9 TH |
1150 | if (unlikely(!tg)) |
1151 | goto out_unlock; | |
f469a7b4 | 1152 | |
e43473b7 VG |
1153 | if (tg->nr_queued[rw]) { |
1154 | /* | |
1155 | * There is already another bio queued in same dir. No | |
1156 | * need to update dispatch time. | |
1157 | */ | |
231d704b | 1158 | update_disptime = false; |
e43473b7 | 1159 | goto queue_bio; |
de701c74 | 1160 | |
e43473b7 VG |
1161 | } |
1162 | ||
1163 | /* Bio is with-in rate limit of group */ | |
1164 | if (tg_may_dispatch(td, tg, bio, NULL)) { | |
1165 | throtl_charge_bio(tg, bio); | |
04521db0 VG |
1166 | |
1167 | /* | |
1168 | * We need to trim slice even when bios are not being queued | |
1169 | * otherwise it might happen that a bio is not queued for | |
1170 | * a long time and slice keeps on extending and trim is not | |
1171 | * called for a long time. Now if limits are reduced suddenly | |
1172 | * we take into account all the IO dispatched so far at new | |
1173 | * low rate and * newly queued IO gets a really long dispatch | |
1174 | * time. | |
1175 | * | |
1176 | * So keep on trimming slice even if bio is not queued. | |
1177 | */ | |
1178 | throtl_trim_slice(td, tg, rw); | |
bc16a4f9 | 1179 | goto out_unlock; |
e43473b7 VG |
1180 | } |
1181 | ||
1182 | queue_bio: | |
fd16d263 | 1183 | throtl_log_tg(td, tg, "[%c] bio. bdisp=%llu sz=%u bps=%llu" |
8e89d13f VG |
1184 | " iodisp=%u iops=%u queued=%d/%d", |
1185 | rw == READ ? 'R' : 'W', | |
e43473b7 | 1186 | tg->bytes_disp[rw], bio->bi_size, tg->bps[rw], |
8e89d13f | 1187 | tg->io_disp[rw], tg->iops[rw], |
e43473b7 VG |
1188 | tg->nr_queued[READ], tg->nr_queued[WRITE]); |
1189 | ||
671058fb | 1190 | bio_associate_current(bio); |
e43473b7 | 1191 | throtl_add_bio_tg(q->td, tg, bio); |
bc16a4f9 | 1192 | throttled = true; |
e43473b7 VG |
1193 | |
1194 | if (update_disptime) { | |
1195 | tg_update_disptime(td, tg); | |
1196 | throtl_schedule_next_dispatch(td); | |
1197 | } | |
1198 | ||
bc16a4f9 | 1199 | out_unlock: |
e43473b7 | 1200 | spin_unlock_irq(q->queue_lock); |
2a7f1244 TH |
1201 | out_unlock_rcu: |
1202 | rcu_read_unlock(); | |
bc16a4f9 TH |
1203 | out: |
1204 | return throttled; | |
e43473b7 VG |
1205 | } |
1206 | ||
c9a929dd TH |
1207 | /** |
1208 | * blk_throtl_drain - drain throttled bios | |
1209 | * @q: request_queue to drain throttled bios for | |
1210 | * | |
1211 | * Dispatch all currently throttled bios on @q through ->make_request_fn(). | |
1212 | */ | |
1213 | void blk_throtl_drain(struct request_queue *q) | |
1214 | __releases(q->queue_lock) __acquires(q->queue_lock) | |
1215 | { | |
1216 | struct throtl_data *td = q->td; | |
1217 | struct throtl_rb_root *st = &td->tg_service_tree; | |
1218 | struct throtl_grp *tg; | |
1219 | struct bio_list bl; | |
1220 | struct bio *bio; | |
1221 | ||
334c2b0b | 1222 | WARN_ON_ONCE(!queue_is_locked(q)); |
c9a929dd TH |
1223 | |
1224 | bio_list_init(&bl); | |
1225 | ||
1226 | while ((tg = throtl_rb_first(st))) { | |
1227 | throtl_dequeue_tg(td, tg); | |
1228 | ||
1229 | while ((bio = bio_list_peek(&tg->bio_lists[READ]))) | |
1230 | tg_dispatch_one_bio(td, tg, bio_data_dir(bio), &bl); | |
1231 | while ((bio = bio_list_peek(&tg->bio_lists[WRITE]))) | |
1232 | tg_dispatch_one_bio(td, tg, bio_data_dir(bio), &bl); | |
1233 | } | |
1234 | spin_unlock_irq(q->queue_lock); | |
1235 | ||
1236 | while ((bio = bio_list_pop(&bl))) | |
1237 | generic_make_request(bio); | |
1238 | ||
1239 | spin_lock_irq(q->queue_lock); | |
1240 | } | |
1241 | ||
e43473b7 VG |
1242 | int blk_throtl_init(struct request_queue *q) |
1243 | { | |
1244 | struct throtl_data *td; | |
a2b1693b | 1245 | int ret; |
e43473b7 VG |
1246 | |
1247 | td = kzalloc_node(sizeof(*td), GFP_KERNEL, q->node); | |
1248 | if (!td) | |
1249 | return -ENOMEM; | |
1250 | ||
e43473b7 | 1251 | td->tg_service_tree = THROTL_RB_ROOT; |
de701c74 | 1252 | td->limits_changed = false; |
a29a171e | 1253 | INIT_DELAYED_WORK(&td->throtl_work, blk_throtl_work); |
e43473b7 | 1254 | |
cd1604fa | 1255 | q->td = td; |
29b12589 | 1256 | td->queue = q; |
02977e4a | 1257 | |
a2b1693b | 1258 | /* activate policy */ |
3c798398 | 1259 | ret = blkcg_activate_policy(q, &blkcg_policy_throtl); |
a2b1693b | 1260 | if (ret) |
f51b802c | 1261 | kfree(td); |
a2b1693b | 1262 | return ret; |
e43473b7 VG |
1263 | } |
1264 | ||
1265 | void blk_throtl_exit(struct request_queue *q) | |
1266 | { | |
c875f4d0 | 1267 | BUG_ON(!q->td); |
da527770 | 1268 | throtl_shutdown_wq(q); |
3c798398 | 1269 | blkcg_deactivate_policy(q, &blkcg_policy_throtl); |
c9a929dd | 1270 | kfree(q->td); |
e43473b7 VG |
1271 | } |
1272 | ||
1273 | static int __init throtl_init(void) | |
1274 | { | |
450adcbe VG |
1275 | kthrotld_workqueue = alloc_workqueue("kthrotld", WQ_MEM_RECLAIM, 0); |
1276 | if (!kthrotld_workqueue) | |
1277 | panic("Failed to create kthrotld\n"); | |
1278 | ||
3c798398 | 1279 | return blkcg_policy_register(&blkcg_policy_throtl); |
e43473b7 VG |
1280 | } |
1281 | ||
1282 | module_init(throtl_init); |