]>
Commit | Line | Data |
---|---|---|
b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
e43473b7 VG |
2 | /* |
3 | * Interface for controlling IO bandwidth on a request queue | |
4 | * | |
5 | * Copyright (C) 2010 Vivek Goyal <[email protected]> | |
6 | */ | |
7 | ||
8 | #include <linux/module.h> | |
9 | #include <linux/slab.h> | |
10 | #include <linux/blkdev.h> | |
11 | #include <linux/bio.h> | |
12 | #include <linux/blktrace_api.h> | |
eea8f41c | 13 | #include <linux/blk-cgroup.h> |
bc9fcbf9 | 14 | #include "blk.h" |
1d156646 | 15 | #include "blk-cgroup-rwstat.h" |
e43473b7 VG |
16 | |
17 | /* Max dispatch from a group in 1 round */ | |
18 | static int throtl_grp_quantum = 8; | |
19 | ||
20 | /* Total max dispatch from all groups in one round */ | |
21 | static int throtl_quantum = 32; | |
22 | ||
d61fcfa4 SL |
23 | /* Throttling is performed over a slice and after that slice is renewed */ |
24 | #define DFL_THROTL_SLICE_HD (HZ / 10) | |
25 | #define DFL_THROTL_SLICE_SSD (HZ / 50) | |
297e3d85 | 26 | #define MAX_THROTL_SLICE (HZ) |
9e234eea | 27 | #define MAX_IDLE_TIME (5L * 1000 * 1000) /* 5 s */ |
9bb67aeb SL |
28 | #define MIN_THROTL_BPS (320 * 1024) |
29 | #define MIN_THROTL_IOPS (10) | |
b4f428ef SL |
30 | #define DFL_LATENCY_TARGET (-1L) |
31 | #define DFL_IDLE_THRESHOLD (0) | |
6679a90c SL |
32 | #define DFL_HD_BASELINE_LATENCY (4000L) /* 4ms */ |
33 | #define LATENCY_FILTERED_SSD (0) | |
34 | /* | |
35 | * For HD, very small latency comes from sequential IO. Such IO is helpless to | |
36 | * help determine if its IO is impacted by others, hence we ignore the IO | |
37 | */ | |
38 | #define LATENCY_FILTERED_HD (1000L) /* 1ms */ | |
e43473b7 | 39 | |
3c798398 | 40 | static struct blkcg_policy blkcg_policy_throtl; |
0381411e | 41 | |
450adcbe VG |
42 | /* A workqueue to queue throttle related work */ |
43 | static struct workqueue_struct *kthrotld_workqueue; | |
450adcbe | 44 | |
c5cc2070 TH |
45 | /* |
46 | * To implement hierarchical throttling, throtl_grps form a tree and bios | |
47 | * are dispatched upwards level by level until they reach the top and get | |
48 | * issued. When dispatching bios from the children and local group at each | |
49 | * level, if the bios are dispatched into a single bio_list, there's a risk | |
50 | * of a local or child group which can queue many bios at once filling up | |
51 | * the list starving others. | |
52 | * | |
53 | * To avoid such starvation, dispatched bios are queued separately | |
54 | * according to where they came from. When they are again dispatched to | |
55 | * the parent, they're popped in round-robin order so that no single source | |
56 | * hogs the dispatch window. | |
57 | * | |
58 | * throtl_qnode is used to keep the queued bios separated by their sources. | |
59 | * Bios are queued to throtl_qnode which in turn is queued to | |
60 | * throtl_service_queue and then dispatched in round-robin order. | |
61 | * | |
62 | * It's also used to track the reference counts on blkg's. A qnode always | |
63 | * belongs to a throtl_grp and gets queued on itself or the parent, so | |
64 | * incrementing the reference of the associated throtl_grp when a qnode is | |
65 | * queued and decrementing when dequeued is enough to keep the whole blkg | |
66 | * tree pinned while bios are in flight. | |
67 | */ | |
68 | struct throtl_qnode { | |
69 | struct list_head node; /* service_queue->queued[] */ | |
70 | struct bio_list bios; /* queued bios */ | |
71 | struct throtl_grp *tg; /* tg this qnode belongs to */ | |
72 | }; | |
73 | ||
c9e0332e | 74 | struct throtl_service_queue { |
77216b04 TH |
75 | struct throtl_service_queue *parent_sq; /* the parent service_queue */ |
76 | ||
73f0d49a TH |
77 | /* |
78 | * Bios queued directly to this service_queue or dispatched from | |
79 | * children throtl_grp's. | |
80 | */ | |
c5cc2070 | 81 | struct list_head queued[2]; /* throtl_qnode [READ/WRITE] */ |
73f0d49a TH |
82 | unsigned int nr_queued[2]; /* number of queued bios */ |
83 | ||
84 | /* | |
85 | * RB tree of active children throtl_grp's, which are sorted by | |
86 | * their ->disptime. | |
87 | */ | |
9ff01255 | 88 | struct rb_root_cached pending_tree; /* RB tree of active tgs */ |
c9e0332e TH |
89 | unsigned int nr_pending; /* # queued in the tree */ |
90 | unsigned long first_pending_disptime; /* disptime of the first tg */ | |
69df0ab0 | 91 | struct timer_list pending_timer; /* fires on first_pending_disptime */ |
e43473b7 VG |
92 | }; |
93 | ||
5b2c16aa TH |
94 | enum tg_state_flags { |
95 | THROTL_TG_PENDING = 1 << 0, /* on parent's pending tree */ | |
0e9f4164 | 96 | THROTL_TG_WAS_EMPTY = 1 << 1, /* bio_lists[] became non-empty */ |
5b2c16aa TH |
97 | }; |
98 | ||
e43473b7 VG |
99 | #define rb_entry_tg(node) rb_entry((node), struct throtl_grp, rb_node) |
100 | ||
9f626e37 | 101 | enum { |
cd5ab1b0 | 102 | LIMIT_LOW, |
9f626e37 SL |
103 | LIMIT_MAX, |
104 | LIMIT_CNT, | |
105 | }; | |
106 | ||
e43473b7 | 107 | struct throtl_grp { |
f95a04af TH |
108 | /* must be the first member */ |
109 | struct blkg_policy_data pd; | |
110 | ||
c9e0332e | 111 | /* active throtl group service_queue member */ |
e43473b7 VG |
112 | struct rb_node rb_node; |
113 | ||
0f3457f6 TH |
114 | /* throtl_data this group belongs to */ |
115 | struct throtl_data *td; | |
116 | ||
49a2f1e3 TH |
117 | /* this group's service queue */ |
118 | struct throtl_service_queue service_queue; | |
119 | ||
c5cc2070 TH |
120 | /* |
121 | * qnode_on_self is used when bios are directly queued to this | |
122 | * throtl_grp so that local bios compete fairly with bios | |
123 | * dispatched from children. qnode_on_parent is used when bios are | |
124 | * dispatched from this throtl_grp into its parent and will compete | |
125 | * with the sibling qnode_on_parents and the parent's | |
126 | * qnode_on_self. | |
127 | */ | |
128 | struct throtl_qnode qnode_on_self[2]; | |
129 | struct throtl_qnode qnode_on_parent[2]; | |
130 | ||
e43473b7 VG |
131 | /* |
132 | * Dispatch time in jiffies. This is the estimated time when group | |
133 | * will unthrottle and is ready to dispatch more bio. It is used as | |
134 | * key to sort active groups in service tree. | |
135 | */ | |
136 | unsigned long disptime; | |
137 | ||
e43473b7 VG |
138 | unsigned int flags; |
139 | ||
693e751e TH |
140 | /* are there any throtl rules between this group and td? */ |
141 | bool has_rules[2]; | |
142 | ||
cd5ab1b0 | 143 | /* internally used bytes per second rate limits */ |
9f626e37 | 144 | uint64_t bps[2][LIMIT_CNT]; |
cd5ab1b0 SL |
145 | /* user configured bps limits */ |
146 | uint64_t bps_conf[2][LIMIT_CNT]; | |
e43473b7 | 147 | |
cd5ab1b0 | 148 | /* internally used IOPS limits */ |
9f626e37 | 149 | unsigned int iops[2][LIMIT_CNT]; |
cd5ab1b0 SL |
150 | /* user configured IOPS limits */ |
151 | unsigned int iops_conf[2][LIMIT_CNT]; | |
8e89d13f | 152 | |
e43473b7 VG |
153 | /* Number of bytes disptached in current slice */ |
154 | uint64_t bytes_disp[2]; | |
8e89d13f VG |
155 | /* Number of bio's dispatched in current slice */ |
156 | unsigned int io_disp[2]; | |
e43473b7 | 157 | |
3f0abd80 SL |
158 | unsigned long last_low_overflow_time[2]; |
159 | ||
160 | uint64_t last_bytes_disp[2]; | |
161 | unsigned int last_io_disp[2]; | |
162 | ||
163 | unsigned long last_check_time; | |
164 | ||
ec80991d | 165 | unsigned long latency_target; /* us */ |
5b81fc3c | 166 | unsigned long latency_target_conf; /* us */ |
e43473b7 VG |
167 | /* When did we start a new slice */ |
168 | unsigned long slice_start[2]; | |
169 | unsigned long slice_end[2]; | |
9e234eea SL |
170 | |
171 | unsigned long last_finish_time; /* ns / 1024 */ | |
172 | unsigned long checked_last_finish_time; /* ns / 1024 */ | |
173 | unsigned long avg_idletime; /* ns / 1024 */ | |
174 | unsigned long idletime_threshold; /* us */ | |
5b81fc3c | 175 | unsigned long idletime_threshold_conf; /* us */ |
53696b8d SL |
176 | |
177 | unsigned int bio_cnt; /* total bios */ | |
178 | unsigned int bad_bio_cnt; /* bios exceeding latency threshold */ | |
179 | unsigned long bio_cnt_reset_time; | |
7ca46438 TH |
180 | |
181 | struct blkg_rwstat stat_bytes; | |
182 | struct blkg_rwstat stat_ios; | |
e43473b7 VG |
183 | }; |
184 | ||
b9147dd1 SL |
185 | /* We measure latency for request size from <= 4k to >= 1M */ |
186 | #define LATENCY_BUCKET_SIZE 9 | |
187 | ||
188 | struct latency_bucket { | |
189 | unsigned long total_latency; /* ns / 1024 */ | |
190 | int samples; | |
191 | }; | |
192 | ||
193 | struct avg_latency_bucket { | |
194 | unsigned long latency; /* ns / 1024 */ | |
195 | bool valid; | |
196 | }; | |
197 | ||
e43473b7 VG |
198 | struct throtl_data |
199 | { | |
e43473b7 | 200 | /* service tree for active throtl groups */ |
c9e0332e | 201 | struct throtl_service_queue service_queue; |
e43473b7 | 202 | |
e43473b7 VG |
203 | struct request_queue *queue; |
204 | ||
205 | /* Total Number of queued bios on READ and WRITE lists */ | |
206 | unsigned int nr_queued[2]; | |
207 | ||
297e3d85 SL |
208 | unsigned int throtl_slice; |
209 | ||
e43473b7 | 210 | /* Work for dispatching throttled bios */ |
69df0ab0 | 211 | struct work_struct dispatch_work; |
9f626e37 SL |
212 | unsigned int limit_index; |
213 | bool limit_valid[LIMIT_CNT]; | |
3f0abd80 SL |
214 | |
215 | unsigned long low_upgrade_time; | |
216 | unsigned long low_downgrade_time; | |
7394e31f SL |
217 | |
218 | unsigned int scale; | |
b9147dd1 | 219 | |
b889bf66 JQ |
220 | struct latency_bucket tmp_buckets[2][LATENCY_BUCKET_SIZE]; |
221 | struct avg_latency_bucket avg_buckets[2][LATENCY_BUCKET_SIZE]; | |
222 | struct latency_bucket __percpu *latency_buckets[2]; | |
b9147dd1 | 223 | unsigned long last_calculate_time; |
6679a90c | 224 | unsigned long filtered_latency; |
b9147dd1 SL |
225 | |
226 | bool track_bio_latency; | |
e43473b7 VG |
227 | }; |
228 | ||
e99e88a9 | 229 | static void throtl_pending_timer_fn(struct timer_list *t); |
69df0ab0 | 230 | |
f95a04af TH |
231 | static inline struct throtl_grp *pd_to_tg(struct blkg_policy_data *pd) |
232 | { | |
233 | return pd ? container_of(pd, struct throtl_grp, pd) : NULL; | |
234 | } | |
235 | ||
3c798398 | 236 | static inline struct throtl_grp *blkg_to_tg(struct blkcg_gq *blkg) |
0381411e | 237 | { |
f95a04af | 238 | return pd_to_tg(blkg_to_pd(blkg, &blkcg_policy_throtl)); |
0381411e TH |
239 | } |
240 | ||
3c798398 | 241 | static inline struct blkcg_gq *tg_to_blkg(struct throtl_grp *tg) |
0381411e | 242 | { |
f95a04af | 243 | return pd_to_blkg(&tg->pd); |
0381411e TH |
244 | } |
245 | ||
fda6f272 TH |
246 | /** |
247 | * sq_to_tg - return the throl_grp the specified service queue belongs to | |
248 | * @sq: the throtl_service_queue of interest | |
249 | * | |
250 | * Return the throtl_grp @sq belongs to. If @sq is the top-level one | |
251 | * embedded in throtl_data, %NULL is returned. | |
252 | */ | |
253 | static struct throtl_grp *sq_to_tg(struct throtl_service_queue *sq) | |
254 | { | |
255 | if (sq && sq->parent_sq) | |
256 | return container_of(sq, struct throtl_grp, service_queue); | |
257 | else | |
258 | return NULL; | |
259 | } | |
260 | ||
261 | /** | |
262 | * sq_to_td - return throtl_data the specified service queue belongs to | |
263 | * @sq: the throtl_service_queue of interest | |
264 | * | |
b43daedc | 265 | * A service_queue can be embedded in either a throtl_grp or throtl_data. |
fda6f272 TH |
266 | * Determine the associated throtl_data accordingly and return it. |
267 | */ | |
268 | static struct throtl_data *sq_to_td(struct throtl_service_queue *sq) | |
269 | { | |
270 | struct throtl_grp *tg = sq_to_tg(sq); | |
271 | ||
272 | if (tg) | |
273 | return tg->td; | |
274 | else | |
275 | return container_of(sq, struct throtl_data, service_queue); | |
276 | } | |
277 | ||
7394e31f SL |
278 | /* |
279 | * cgroup's limit in LIMIT_MAX is scaled if low limit is set. This scale is to | |
280 | * make the IO dispatch more smooth. | |
281 | * Scale up: linearly scale up according to lapsed time since upgrade. For | |
282 | * every throtl_slice, the limit scales up 1/2 .low limit till the | |
283 | * limit hits .max limit | |
284 | * Scale down: exponentially scale down if a cgroup doesn't hit its .low limit | |
285 | */ | |
286 | static uint64_t throtl_adjusted_limit(uint64_t low, struct throtl_data *td) | |
287 | { | |
288 | /* arbitrary value to avoid too big scale */ | |
289 | if (td->scale < 4096 && time_after_eq(jiffies, | |
290 | td->low_upgrade_time + td->scale * td->throtl_slice)) | |
291 | td->scale = (jiffies - td->low_upgrade_time) / td->throtl_slice; | |
292 | ||
293 | return low + (low >> 1) * td->scale; | |
294 | } | |
295 | ||
9f626e37 SL |
296 | static uint64_t tg_bps_limit(struct throtl_grp *tg, int rw) |
297 | { | |
b22c417c | 298 | struct blkcg_gq *blkg = tg_to_blkg(tg); |
7394e31f | 299 | struct throtl_data *td; |
b22c417c SL |
300 | uint64_t ret; |
301 | ||
302 | if (cgroup_subsys_on_dfl(io_cgrp_subsys) && !blkg->parent) | |
303 | return U64_MAX; | |
7394e31f SL |
304 | |
305 | td = tg->td; | |
306 | ret = tg->bps[rw][td->limit_index]; | |
9bb67aeb SL |
307 | if (ret == 0 && td->limit_index == LIMIT_LOW) { |
308 | /* intermediate node or iops isn't 0 */ | |
309 | if (!list_empty(&blkg->blkcg->css.children) || | |
310 | tg->iops[rw][td->limit_index]) | |
311 | return U64_MAX; | |
312 | else | |
313 | return MIN_THROTL_BPS; | |
314 | } | |
7394e31f SL |
315 | |
316 | if (td->limit_index == LIMIT_MAX && tg->bps[rw][LIMIT_LOW] && | |
317 | tg->bps[rw][LIMIT_LOW] != tg->bps[rw][LIMIT_MAX]) { | |
318 | uint64_t adjusted; | |
319 | ||
320 | adjusted = throtl_adjusted_limit(tg->bps[rw][LIMIT_LOW], td); | |
321 | ret = min(tg->bps[rw][LIMIT_MAX], adjusted); | |
322 | } | |
b22c417c | 323 | return ret; |
9f626e37 SL |
324 | } |
325 | ||
326 | static unsigned int tg_iops_limit(struct throtl_grp *tg, int rw) | |
327 | { | |
b22c417c | 328 | struct blkcg_gq *blkg = tg_to_blkg(tg); |
7394e31f | 329 | struct throtl_data *td; |
b22c417c SL |
330 | unsigned int ret; |
331 | ||
332 | if (cgroup_subsys_on_dfl(io_cgrp_subsys) && !blkg->parent) | |
333 | return UINT_MAX; | |
9bb67aeb | 334 | |
7394e31f SL |
335 | td = tg->td; |
336 | ret = tg->iops[rw][td->limit_index]; | |
9bb67aeb SL |
337 | if (ret == 0 && tg->td->limit_index == LIMIT_LOW) { |
338 | /* intermediate node or bps isn't 0 */ | |
339 | if (!list_empty(&blkg->blkcg->css.children) || | |
340 | tg->bps[rw][td->limit_index]) | |
341 | return UINT_MAX; | |
342 | else | |
343 | return MIN_THROTL_IOPS; | |
344 | } | |
7394e31f SL |
345 | |
346 | if (td->limit_index == LIMIT_MAX && tg->iops[rw][LIMIT_LOW] && | |
347 | tg->iops[rw][LIMIT_LOW] != tg->iops[rw][LIMIT_MAX]) { | |
348 | uint64_t adjusted; | |
349 | ||
350 | adjusted = throtl_adjusted_limit(tg->iops[rw][LIMIT_LOW], td); | |
351 | if (adjusted > UINT_MAX) | |
352 | adjusted = UINT_MAX; | |
353 | ret = min_t(unsigned int, tg->iops[rw][LIMIT_MAX], adjusted); | |
354 | } | |
b22c417c | 355 | return ret; |
9f626e37 SL |
356 | } |
357 | ||
b9147dd1 SL |
358 | #define request_bucket_index(sectors) \ |
359 | clamp_t(int, order_base_2(sectors) - 3, 0, LATENCY_BUCKET_SIZE - 1) | |
360 | ||
fda6f272 TH |
361 | /** |
362 | * throtl_log - log debug message via blktrace | |
363 | * @sq: the service_queue being reported | |
364 | * @fmt: printf format string | |
365 | * @args: printf args | |
366 | * | |
367 | * The messages are prefixed with "throtl BLKG_NAME" if @sq belongs to a | |
368 | * throtl_grp; otherwise, just "throtl". | |
fda6f272 TH |
369 | */ |
370 | #define throtl_log(sq, fmt, args...) do { \ | |
371 | struct throtl_grp *__tg = sq_to_tg((sq)); \ | |
372 | struct throtl_data *__td = sq_to_td((sq)); \ | |
373 | \ | |
374 | (void)__td; \ | |
59fa0224 SL |
375 | if (likely(!blk_trace_note_message_enabled(__td->queue))) \ |
376 | break; \ | |
fda6f272 | 377 | if ((__tg)) { \ |
35fe6d76 SL |
378 | blk_add_cgroup_trace_msg(__td->queue, \ |
379 | tg_to_blkg(__tg)->blkcg, "throtl " fmt, ##args);\ | |
fda6f272 TH |
380 | } else { \ |
381 | blk_add_trace_msg(__td->queue, "throtl " fmt, ##args); \ | |
382 | } \ | |
54e7ed12 | 383 | } while (0) |
e43473b7 | 384 | |
ea0ea2bc SL |
385 | static inline unsigned int throtl_bio_data_size(struct bio *bio) |
386 | { | |
387 | /* assume it's one sector */ | |
388 | if (unlikely(bio_op(bio) == REQ_OP_DISCARD)) | |
389 | return 512; | |
390 | return bio->bi_iter.bi_size; | |
391 | } | |
392 | ||
c5cc2070 TH |
393 | static void throtl_qnode_init(struct throtl_qnode *qn, struct throtl_grp *tg) |
394 | { | |
395 | INIT_LIST_HEAD(&qn->node); | |
396 | bio_list_init(&qn->bios); | |
397 | qn->tg = tg; | |
398 | } | |
399 | ||
400 | /** | |
401 | * throtl_qnode_add_bio - add a bio to a throtl_qnode and activate it | |
402 | * @bio: bio being added | |
403 | * @qn: qnode to add bio to | |
404 | * @queued: the service_queue->queued[] list @qn belongs to | |
405 | * | |
406 | * Add @bio to @qn and put @qn on @queued if it's not already on. | |
407 | * @qn->tg's reference count is bumped when @qn is activated. See the | |
408 | * comment on top of throtl_qnode definition for details. | |
409 | */ | |
410 | static void throtl_qnode_add_bio(struct bio *bio, struct throtl_qnode *qn, | |
411 | struct list_head *queued) | |
412 | { | |
413 | bio_list_add(&qn->bios, bio); | |
414 | if (list_empty(&qn->node)) { | |
415 | list_add_tail(&qn->node, queued); | |
416 | blkg_get(tg_to_blkg(qn->tg)); | |
417 | } | |
418 | } | |
419 | ||
420 | /** | |
421 | * throtl_peek_queued - peek the first bio on a qnode list | |
422 | * @queued: the qnode list to peek | |
423 | */ | |
424 | static struct bio *throtl_peek_queued(struct list_head *queued) | |
425 | { | |
426 | struct throtl_qnode *qn = list_first_entry(queued, struct throtl_qnode, node); | |
427 | struct bio *bio; | |
428 | ||
429 | if (list_empty(queued)) | |
430 | return NULL; | |
431 | ||
432 | bio = bio_list_peek(&qn->bios); | |
433 | WARN_ON_ONCE(!bio); | |
434 | return bio; | |
435 | } | |
436 | ||
437 | /** | |
438 | * throtl_pop_queued - pop the first bio form a qnode list | |
439 | * @queued: the qnode list to pop a bio from | |
440 | * @tg_to_put: optional out argument for throtl_grp to put | |
441 | * | |
442 | * Pop the first bio from the qnode list @queued. After popping, the first | |
443 | * qnode is removed from @queued if empty or moved to the end of @queued so | |
444 | * that the popping order is round-robin. | |
445 | * | |
446 | * When the first qnode is removed, its associated throtl_grp should be put | |
447 | * too. If @tg_to_put is NULL, this function automatically puts it; | |
448 | * otherwise, *@tg_to_put is set to the throtl_grp to put and the caller is | |
449 | * responsible for putting it. | |
450 | */ | |
451 | static struct bio *throtl_pop_queued(struct list_head *queued, | |
452 | struct throtl_grp **tg_to_put) | |
453 | { | |
454 | struct throtl_qnode *qn = list_first_entry(queued, struct throtl_qnode, node); | |
455 | struct bio *bio; | |
456 | ||
457 | if (list_empty(queued)) | |
458 | return NULL; | |
459 | ||
460 | bio = bio_list_pop(&qn->bios); | |
461 | WARN_ON_ONCE(!bio); | |
462 | ||
463 | if (bio_list_empty(&qn->bios)) { | |
464 | list_del_init(&qn->node); | |
465 | if (tg_to_put) | |
466 | *tg_to_put = qn->tg; | |
467 | else | |
468 | blkg_put(tg_to_blkg(qn->tg)); | |
469 | } else { | |
470 | list_move_tail(&qn->node, queued); | |
471 | } | |
472 | ||
473 | return bio; | |
474 | } | |
475 | ||
49a2f1e3 | 476 | /* init a service_queue, assumes the caller zeroed it */ |
b2ce2643 | 477 | static void throtl_service_queue_init(struct throtl_service_queue *sq) |
49a2f1e3 | 478 | { |
c5cc2070 TH |
479 | INIT_LIST_HEAD(&sq->queued[0]); |
480 | INIT_LIST_HEAD(&sq->queued[1]); | |
9ff01255 | 481 | sq->pending_tree = RB_ROOT_CACHED; |
e99e88a9 | 482 | timer_setup(&sq->pending_timer, throtl_pending_timer_fn, 0); |
69df0ab0 TH |
483 | } |
484 | ||
cf09a8ee TH |
485 | static struct blkg_policy_data *throtl_pd_alloc(gfp_t gfp, |
486 | struct request_queue *q, | |
487 | struct blkcg *blkcg) | |
001bea73 | 488 | { |
4fb72036 | 489 | struct throtl_grp *tg; |
24bdb8ef | 490 | int rw; |
4fb72036 | 491 | |
cf09a8ee | 492 | tg = kzalloc_node(sizeof(*tg), gfp, q->node); |
4fb72036 | 493 | if (!tg) |
77ea7338 | 494 | return NULL; |
4fb72036 | 495 | |
7ca46438 TH |
496 | if (blkg_rwstat_init(&tg->stat_bytes, gfp)) |
497 | goto err_free_tg; | |
498 | ||
499 | if (blkg_rwstat_init(&tg->stat_ios, gfp)) | |
500 | goto err_exit_stat_bytes; | |
501 | ||
b2ce2643 TH |
502 | throtl_service_queue_init(&tg->service_queue); |
503 | ||
504 | for (rw = READ; rw <= WRITE; rw++) { | |
505 | throtl_qnode_init(&tg->qnode_on_self[rw], tg); | |
506 | throtl_qnode_init(&tg->qnode_on_parent[rw], tg); | |
507 | } | |
508 | ||
509 | RB_CLEAR_NODE(&tg->rb_node); | |
9f626e37 SL |
510 | tg->bps[READ][LIMIT_MAX] = U64_MAX; |
511 | tg->bps[WRITE][LIMIT_MAX] = U64_MAX; | |
512 | tg->iops[READ][LIMIT_MAX] = UINT_MAX; | |
513 | tg->iops[WRITE][LIMIT_MAX] = UINT_MAX; | |
cd5ab1b0 SL |
514 | tg->bps_conf[READ][LIMIT_MAX] = U64_MAX; |
515 | tg->bps_conf[WRITE][LIMIT_MAX] = U64_MAX; | |
516 | tg->iops_conf[READ][LIMIT_MAX] = UINT_MAX; | |
517 | tg->iops_conf[WRITE][LIMIT_MAX] = UINT_MAX; | |
518 | /* LIMIT_LOW will have default value 0 */ | |
b2ce2643 | 519 | |
ec80991d | 520 | tg->latency_target = DFL_LATENCY_TARGET; |
5b81fc3c | 521 | tg->latency_target_conf = DFL_LATENCY_TARGET; |
b4f428ef SL |
522 | tg->idletime_threshold = DFL_IDLE_THRESHOLD; |
523 | tg->idletime_threshold_conf = DFL_IDLE_THRESHOLD; | |
ec80991d | 524 | |
4fb72036 | 525 | return &tg->pd; |
7ca46438 TH |
526 | |
527 | err_exit_stat_bytes: | |
528 | blkg_rwstat_exit(&tg->stat_bytes); | |
529 | err_free_tg: | |
530 | kfree(tg); | |
531 | return NULL; | |
001bea73 TH |
532 | } |
533 | ||
a9520cd6 | 534 | static void throtl_pd_init(struct blkg_policy_data *pd) |
a29a171e | 535 | { |
a9520cd6 TH |
536 | struct throtl_grp *tg = pd_to_tg(pd); |
537 | struct blkcg_gq *blkg = tg_to_blkg(tg); | |
77216b04 | 538 | struct throtl_data *td = blkg->q->td; |
b2ce2643 | 539 | struct throtl_service_queue *sq = &tg->service_queue; |
cd1604fa | 540 | |
9138125b | 541 | /* |
aa6ec29b | 542 | * If on the default hierarchy, we switch to properly hierarchical |
9138125b TH |
543 | * behavior where limits on a given throtl_grp are applied to the |
544 | * whole subtree rather than just the group itself. e.g. If 16M | |
545 | * read_bps limit is set on the root group, the whole system can't | |
546 | * exceed 16M for the device. | |
547 | * | |
aa6ec29b | 548 | * If not on the default hierarchy, the broken flat hierarchy |
9138125b TH |
549 | * behavior is retained where all throtl_grps are treated as if |
550 | * they're all separate root groups right below throtl_data. | |
551 | * Limits of a group don't interact with limits of other groups | |
552 | * regardless of the position of the group in the hierarchy. | |
553 | */ | |
b2ce2643 | 554 | sq->parent_sq = &td->service_queue; |
9e10a130 | 555 | if (cgroup_subsys_on_dfl(io_cgrp_subsys) && blkg->parent) |
b2ce2643 | 556 | sq->parent_sq = &blkg_to_tg(blkg->parent)->service_queue; |
77216b04 | 557 | tg->td = td; |
8a3d2615 TH |
558 | } |
559 | ||
693e751e TH |
560 | /* |
561 | * Set has_rules[] if @tg or any of its parents have limits configured. | |
562 | * This doesn't require walking up to the top of the hierarchy as the | |
563 | * parent's has_rules[] is guaranteed to be correct. | |
564 | */ | |
565 | static void tg_update_has_rules(struct throtl_grp *tg) | |
566 | { | |
567 | struct throtl_grp *parent_tg = sq_to_tg(tg->service_queue.parent_sq); | |
9f626e37 | 568 | struct throtl_data *td = tg->td; |
693e751e TH |
569 | int rw; |
570 | ||
571 | for (rw = READ; rw <= WRITE; rw++) | |
572 | tg->has_rules[rw] = (parent_tg && parent_tg->has_rules[rw]) || | |
9f626e37 SL |
573 | (td->limit_valid[td->limit_index] && |
574 | (tg_bps_limit(tg, rw) != U64_MAX || | |
575 | tg_iops_limit(tg, rw) != UINT_MAX)); | |
693e751e TH |
576 | } |
577 | ||
a9520cd6 | 578 | static void throtl_pd_online(struct blkg_policy_data *pd) |
693e751e | 579 | { |
aec24246 | 580 | struct throtl_grp *tg = pd_to_tg(pd); |
693e751e TH |
581 | /* |
582 | * We don't want new groups to escape the limits of its ancestors. | |
583 | * Update has_rules[] after a new group is brought online. | |
584 | */ | |
aec24246 | 585 | tg_update_has_rules(tg); |
693e751e TH |
586 | } |
587 | ||
cd5ab1b0 SL |
588 | static void blk_throtl_update_limit_valid(struct throtl_data *td) |
589 | { | |
590 | struct cgroup_subsys_state *pos_css; | |
591 | struct blkcg_gq *blkg; | |
592 | bool low_valid = false; | |
593 | ||
594 | rcu_read_lock(); | |
595 | blkg_for_each_descendant_post(blkg, pos_css, td->queue->root_blkg) { | |
596 | struct throtl_grp *tg = blkg_to_tg(blkg); | |
597 | ||
598 | if (tg->bps[READ][LIMIT_LOW] || tg->bps[WRITE][LIMIT_LOW] || | |
43ada787 | 599 | tg->iops[READ][LIMIT_LOW] || tg->iops[WRITE][LIMIT_LOW]) { |
cd5ab1b0 | 600 | low_valid = true; |
43ada787 LB |
601 | break; |
602 | } | |
cd5ab1b0 SL |
603 | } |
604 | rcu_read_unlock(); | |
605 | ||
606 | td->limit_valid[LIMIT_LOW] = low_valid; | |
607 | } | |
608 | ||
c79892c5 | 609 | static void throtl_upgrade_state(struct throtl_data *td); |
cd5ab1b0 SL |
610 | static void throtl_pd_offline(struct blkg_policy_data *pd) |
611 | { | |
612 | struct throtl_grp *tg = pd_to_tg(pd); | |
613 | ||
614 | tg->bps[READ][LIMIT_LOW] = 0; | |
615 | tg->bps[WRITE][LIMIT_LOW] = 0; | |
616 | tg->iops[READ][LIMIT_LOW] = 0; | |
617 | tg->iops[WRITE][LIMIT_LOW] = 0; | |
618 | ||
619 | blk_throtl_update_limit_valid(tg->td); | |
620 | ||
c79892c5 SL |
621 | if (!tg->td->limit_valid[tg->td->limit_index]) |
622 | throtl_upgrade_state(tg->td); | |
cd5ab1b0 SL |
623 | } |
624 | ||
001bea73 TH |
625 | static void throtl_pd_free(struct blkg_policy_data *pd) |
626 | { | |
4fb72036 TH |
627 | struct throtl_grp *tg = pd_to_tg(pd); |
628 | ||
b2ce2643 | 629 | del_timer_sync(&tg->service_queue.pending_timer); |
7ca46438 TH |
630 | blkg_rwstat_exit(&tg->stat_bytes); |
631 | blkg_rwstat_exit(&tg->stat_ios); | |
4fb72036 | 632 | kfree(tg); |
001bea73 TH |
633 | } |
634 | ||
0049af73 TH |
635 | static struct throtl_grp * |
636 | throtl_rb_first(struct throtl_service_queue *parent_sq) | |
e43473b7 | 637 | { |
9ff01255 | 638 | struct rb_node *n; |
e43473b7 | 639 | /* Service tree is empty */ |
0049af73 | 640 | if (!parent_sq->nr_pending) |
e43473b7 VG |
641 | return NULL; |
642 | ||
9ff01255 LB |
643 | n = rb_first_cached(&parent_sq->pending_tree); |
644 | WARN_ON_ONCE(!n); | |
645 | if (!n) | |
646 | return NULL; | |
647 | return rb_entry_tg(n); | |
e43473b7 VG |
648 | } |
649 | ||
0049af73 TH |
650 | static void throtl_rb_erase(struct rb_node *n, |
651 | struct throtl_service_queue *parent_sq) | |
e43473b7 | 652 | { |
9ff01255 LB |
653 | rb_erase_cached(n, &parent_sq->pending_tree); |
654 | RB_CLEAR_NODE(n); | |
0049af73 | 655 | --parent_sq->nr_pending; |
e43473b7 VG |
656 | } |
657 | ||
0049af73 | 658 | static void update_min_dispatch_time(struct throtl_service_queue *parent_sq) |
e43473b7 VG |
659 | { |
660 | struct throtl_grp *tg; | |
661 | ||
0049af73 | 662 | tg = throtl_rb_first(parent_sq); |
e43473b7 VG |
663 | if (!tg) |
664 | return; | |
665 | ||
0049af73 | 666 | parent_sq->first_pending_disptime = tg->disptime; |
e43473b7 VG |
667 | } |
668 | ||
77216b04 | 669 | static void tg_service_queue_add(struct throtl_grp *tg) |
e43473b7 | 670 | { |
77216b04 | 671 | struct throtl_service_queue *parent_sq = tg->service_queue.parent_sq; |
9ff01255 | 672 | struct rb_node **node = &parent_sq->pending_tree.rb_root.rb_node; |
e43473b7 VG |
673 | struct rb_node *parent = NULL; |
674 | struct throtl_grp *__tg; | |
675 | unsigned long key = tg->disptime; | |
9ff01255 | 676 | bool leftmost = true; |
e43473b7 VG |
677 | |
678 | while (*node != NULL) { | |
679 | parent = *node; | |
680 | __tg = rb_entry_tg(parent); | |
681 | ||
682 | if (time_before(key, __tg->disptime)) | |
683 | node = &parent->rb_left; | |
684 | else { | |
685 | node = &parent->rb_right; | |
9ff01255 | 686 | leftmost = false; |
e43473b7 VG |
687 | } |
688 | } | |
689 | ||
e43473b7 | 690 | rb_link_node(&tg->rb_node, parent, node); |
9ff01255 LB |
691 | rb_insert_color_cached(&tg->rb_node, &parent_sq->pending_tree, |
692 | leftmost); | |
e43473b7 VG |
693 | } |
694 | ||
77216b04 | 695 | static void __throtl_enqueue_tg(struct throtl_grp *tg) |
e43473b7 | 696 | { |
77216b04 | 697 | tg_service_queue_add(tg); |
5b2c16aa | 698 | tg->flags |= THROTL_TG_PENDING; |
77216b04 | 699 | tg->service_queue.parent_sq->nr_pending++; |
e43473b7 VG |
700 | } |
701 | ||
77216b04 | 702 | static void throtl_enqueue_tg(struct throtl_grp *tg) |
e43473b7 | 703 | { |
5b2c16aa | 704 | if (!(tg->flags & THROTL_TG_PENDING)) |
77216b04 | 705 | __throtl_enqueue_tg(tg); |
e43473b7 VG |
706 | } |
707 | ||
77216b04 | 708 | static void __throtl_dequeue_tg(struct throtl_grp *tg) |
e43473b7 | 709 | { |
77216b04 | 710 | throtl_rb_erase(&tg->rb_node, tg->service_queue.parent_sq); |
5b2c16aa | 711 | tg->flags &= ~THROTL_TG_PENDING; |
e43473b7 VG |
712 | } |
713 | ||
77216b04 | 714 | static void throtl_dequeue_tg(struct throtl_grp *tg) |
e43473b7 | 715 | { |
5b2c16aa | 716 | if (tg->flags & THROTL_TG_PENDING) |
77216b04 | 717 | __throtl_dequeue_tg(tg); |
e43473b7 VG |
718 | } |
719 | ||
a9131a27 | 720 | /* Call with queue lock held */ |
69df0ab0 TH |
721 | static void throtl_schedule_pending_timer(struct throtl_service_queue *sq, |
722 | unsigned long expires) | |
a9131a27 | 723 | { |
a41b816c | 724 | unsigned long max_expire = jiffies + 8 * sq_to_td(sq)->throtl_slice; |
06cceedc SL |
725 | |
726 | /* | |
727 | * Since we are adjusting the throttle limit dynamically, the sleep | |
728 | * time calculated according to previous limit might be invalid. It's | |
729 | * possible the cgroup sleep time is very long and no other cgroups | |
730 | * have IO running so notify the limit changes. Make sure the cgroup | |
731 | * doesn't sleep too long to avoid the missed notification. | |
732 | */ | |
733 | if (time_after(expires, max_expire)) | |
734 | expires = max_expire; | |
69df0ab0 TH |
735 | mod_timer(&sq->pending_timer, expires); |
736 | throtl_log(sq, "schedule timer. delay=%lu jiffies=%lu", | |
737 | expires - jiffies, jiffies); | |
a9131a27 TH |
738 | } |
739 | ||
7f52f98c TH |
740 | /** |
741 | * throtl_schedule_next_dispatch - schedule the next dispatch cycle | |
742 | * @sq: the service_queue to schedule dispatch for | |
743 | * @force: force scheduling | |
744 | * | |
745 | * Arm @sq->pending_timer so that the next dispatch cycle starts on the | |
746 | * dispatch time of the first pending child. Returns %true if either timer | |
747 | * is armed or there's no pending child left. %false if the current | |
748 | * dispatch window is still open and the caller should continue | |
749 | * dispatching. | |
750 | * | |
751 | * If @force is %true, the dispatch timer is always scheduled and this | |
752 | * function is guaranteed to return %true. This is to be used when the | |
753 | * caller can't dispatch itself and needs to invoke pending_timer | |
754 | * unconditionally. Note that forced scheduling is likely to induce short | |
755 | * delay before dispatch starts even if @sq->first_pending_disptime is not | |
756 | * in the future and thus shouldn't be used in hot paths. | |
757 | */ | |
758 | static bool throtl_schedule_next_dispatch(struct throtl_service_queue *sq, | |
759 | bool force) | |
e43473b7 | 760 | { |
6a525600 | 761 | /* any pending children left? */ |
c9e0332e | 762 | if (!sq->nr_pending) |
7f52f98c | 763 | return true; |
e43473b7 | 764 | |
c9e0332e | 765 | update_min_dispatch_time(sq); |
e43473b7 | 766 | |
69df0ab0 | 767 | /* is the next dispatch time in the future? */ |
7f52f98c | 768 | if (force || time_after(sq->first_pending_disptime, jiffies)) { |
69df0ab0 | 769 | throtl_schedule_pending_timer(sq, sq->first_pending_disptime); |
7f52f98c | 770 | return true; |
69df0ab0 TH |
771 | } |
772 | ||
7f52f98c TH |
773 | /* tell the caller to continue dispatching */ |
774 | return false; | |
e43473b7 VG |
775 | } |
776 | ||
32ee5bc4 VG |
777 | static inline void throtl_start_new_slice_with_credit(struct throtl_grp *tg, |
778 | bool rw, unsigned long start) | |
779 | { | |
780 | tg->bytes_disp[rw] = 0; | |
781 | tg->io_disp[rw] = 0; | |
782 | ||
783 | /* | |
784 | * Previous slice has expired. We must have trimmed it after last | |
785 | * bio dispatch. That means since start of last slice, we never used | |
786 | * that bandwidth. Do try to make use of that bandwidth while giving | |
787 | * credit. | |
788 | */ | |
789 | if (time_after_eq(start, tg->slice_start[rw])) | |
790 | tg->slice_start[rw] = start; | |
791 | ||
297e3d85 | 792 | tg->slice_end[rw] = jiffies + tg->td->throtl_slice; |
32ee5bc4 VG |
793 | throtl_log(&tg->service_queue, |
794 | "[%c] new slice with credit start=%lu end=%lu jiffies=%lu", | |
795 | rw == READ ? 'R' : 'W', tg->slice_start[rw], | |
796 | tg->slice_end[rw], jiffies); | |
797 | } | |
798 | ||
0f3457f6 | 799 | static inline void throtl_start_new_slice(struct throtl_grp *tg, bool rw) |
e43473b7 VG |
800 | { |
801 | tg->bytes_disp[rw] = 0; | |
8e89d13f | 802 | tg->io_disp[rw] = 0; |
e43473b7 | 803 | tg->slice_start[rw] = jiffies; |
297e3d85 | 804 | tg->slice_end[rw] = jiffies + tg->td->throtl_slice; |
fda6f272 TH |
805 | throtl_log(&tg->service_queue, |
806 | "[%c] new slice start=%lu end=%lu jiffies=%lu", | |
807 | rw == READ ? 'R' : 'W', tg->slice_start[rw], | |
808 | tg->slice_end[rw], jiffies); | |
e43473b7 VG |
809 | } |
810 | ||
0f3457f6 TH |
811 | static inline void throtl_set_slice_end(struct throtl_grp *tg, bool rw, |
812 | unsigned long jiffy_end) | |
d1ae8ffd | 813 | { |
297e3d85 | 814 | tg->slice_end[rw] = roundup(jiffy_end, tg->td->throtl_slice); |
d1ae8ffd VG |
815 | } |
816 | ||
0f3457f6 TH |
817 | static inline void throtl_extend_slice(struct throtl_grp *tg, bool rw, |
818 | unsigned long jiffy_end) | |
e43473b7 | 819 | { |
297e3d85 | 820 | tg->slice_end[rw] = roundup(jiffy_end, tg->td->throtl_slice); |
fda6f272 TH |
821 | throtl_log(&tg->service_queue, |
822 | "[%c] extend slice start=%lu end=%lu jiffies=%lu", | |
823 | rw == READ ? 'R' : 'W', tg->slice_start[rw], | |
824 | tg->slice_end[rw], jiffies); | |
e43473b7 VG |
825 | } |
826 | ||
827 | /* Determine if previously allocated or extended slice is complete or not */ | |
0f3457f6 | 828 | static bool throtl_slice_used(struct throtl_grp *tg, bool rw) |
e43473b7 VG |
829 | { |
830 | if (time_in_range(jiffies, tg->slice_start[rw], tg->slice_end[rw])) | |
5cf8c227 | 831 | return false; |
e43473b7 | 832 | |
0b6bad7d | 833 | return true; |
e43473b7 VG |
834 | } |
835 | ||
836 | /* Trim the used slices and adjust slice start accordingly */ | |
0f3457f6 | 837 | static inline void throtl_trim_slice(struct throtl_grp *tg, bool rw) |
e43473b7 | 838 | { |
3aad5d3e VG |
839 | unsigned long nr_slices, time_elapsed, io_trim; |
840 | u64 bytes_trim, tmp; | |
e43473b7 VG |
841 | |
842 | BUG_ON(time_before(tg->slice_end[rw], tg->slice_start[rw])); | |
843 | ||
844 | /* | |
845 | * If bps are unlimited (-1), then time slice don't get | |
846 | * renewed. Don't try to trim the slice if slice is used. A new | |
847 | * slice will start when appropriate. | |
848 | */ | |
0f3457f6 | 849 | if (throtl_slice_used(tg, rw)) |
e43473b7 VG |
850 | return; |
851 | ||
d1ae8ffd VG |
852 | /* |
853 | * A bio has been dispatched. Also adjust slice_end. It might happen | |
854 | * that initially cgroup limit was very low resulting in high | |
855 | * slice_end, but later limit was bumped up and bio was dispached | |
856 | * sooner, then we need to reduce slice_end. A high bogus slice_end | |
857 | * is bad because it does not allow new slice to start. | |
858 | */ | |
859 | ||
297e3d85 | 860 | throtl_set_slice_end(tg, rw, jiffies + tg->td->throtl_slice); |
d1ae8ffd | 861 | |
e43473b7 VG |
862 | time_elapsed = jiffies - tg->slice_start[rw]; |
863 | ||
297e3d85 | 864 | nr_slices = time_elapsed / tg->td->throtl_slice; |
e43473b7 VG |
865 | |
866 | if (!nr_slices) | |
867 | return; | |
297e3d85 | 868 | tmp = tg_bps_limit(tg, rw) * tg->td->throtl_slice * nr_slices; |
3aad5d3e VG |
869 | do_div(tmp, HZ); |
870 | bytes_trim = tmp; | |
e43473b7 | 871 | |
297e3d85 SL |
872 | io_trim = (tg_iops_limit(tg, rw) * tg->td->throtl_slice * nr_slices) / |
873 | HZ; | |
e43473b7 | 874 | |
8e89d13f | 875 | if (!bytes_trim && !io_trim) |
e43473b7 VG |
876 | return; |
877 | ||
878 | if (tg->bytes_disp[rw] >= bytes_trim) | |
879 | tg->bytes_disp[rw] -= bytes_trim; | |
880 | else | |
881 | tg->bytes_disp[rw] = 0; | |
882 | ||
8e89d13f VG |
883 | if (tg->io_disp[rw] >= io_trim) |
884 | tg->io_disp[rw] -= io_trim; | |
885 | else | |
886 | tg->io_disp[rw] = 0; | |
887 | ||
297e3d85 | 888 | tg->slice_start[rw] += nr_slices * tg->td->throtl_slice; |
e43473b7 | 889 | |
fda6f272 TH |
890 | throtl_log(&tg->service_queue, |
891 | "[%c] trim slice nr=%lu bytes=%llu io=%lu start=%lu end=%lu jiffies=%lu", | |
892 | rw == READ ? 'R' : 'W', nr_slices, bytes_trim, io_trim, | |
893 | tg->slice_start[rw], tg->slice_end[rw], jiffies); | |
e43473b7 VG |
894 | } |
895 | ||
0f3457f6 TH |
896 | static bool tg_with_in_iops_limit(struct throtl_grp *tg, struct bio *bio, |
897 | unsigned long *wait) | |
e43473b7 VG |
898 | { |
899 | bool rw = bio_data_dir(bio); | |
8e89d13f | 900 | unsigned int io_allowed; |
e43473b7 | 901 | unsigned long jiffy_elapsed, jiffy_wait, jiffy_elapsed_rnd; |
c49c06e4 | 902 | u64 tmp; |
e43473b7 | 903 | |
3a10f999 | 904 | jiffy_elapsed = jiffies - tg->slice_start[rw]; |
e43473b7 | 905 | |
3a10f999 KK |
906 | /* Round up to the next throttle slice, wait time must be nonzero */ |
907 | jiffy_elapsed_rnd = roundup(jiffy_elapsed + 1, tg->td->throtl_slice); | |
8e89d13f | 908 | |
c49c06e4 VG |
909 | /* |
910 | * jiffy_elapsed_rnd should not be a big value as minimum iops can be | |
911 | * 1 then at max jiffy elapsed should be equivalent of 1 second as we | |
912 | * will allow dispatch after 1 second and after that slice should | |
913 | * have been trimmed. | |
914 | */ | |
915 | ||
9f626e37 | 916 | tmp = (u64)tg_iops_limit(tg, rw) * jiffy_elapsed_rnd; |
c49c06e4 VG |
917 | do_div(tmp, HZ); |
918 | ||
919 | if (tmp > UINT_MAX) | |
920 | io_allowed = UINT_MAX; | |
921 | else | |
922 | io_allowed = tmp; | |
8e89d13f VG |
923 | |
924 | if (tg->io_disp[rw] + 1 <= io_allowed) { | |
e43473b7 VG |
925 | if (wait) |
926 | *wait = 0; | |
5cf8c227 | 927 | return true; |
e43473b7 VG |
928 | } |
929 | ||
8e89d13f | 930 | /* Calc approx time to dispatch */ |
991f61fe | 931 | jiffy_wait = jiffy_elapsed_rnd - jiffy_elapsed; |
8e89d13f VG |
932 | |
933 | if (wait) | |
934 | *wait = jiffy_wait; | |
0b6bad7d | 935 | return false; |
8e89d13f VG |
936 | } |
937 | ||
0f3457f6 TH |
938 | static bool tg_with_in_bps_limit(struct throtl_grp *tg, struct bio *bio, |
939 | unsigned long *wait) | |
8e89d13f VG |
940 | { |
941 | bool rw = bio_data_dir(bio); | |
3aad5d3e | 942 | u64 bytes_allowed, extra_bytes, tmp; |
8e89d13f | 943 | unsigned long jiffy_elapsed, jiffy_wait, jiffy_elapsed_rnd; |
ea0ea2bc | 944 | unsigned int bio_size = throtl_bio_data_size(bio); |
e43473b7 VG |
945 | |
946 | jiffy_elapsed = jiffy_elapsed_rnd = jiffies - tg->slice_start[rw]; | |
947 | ||
948 | /* Slice has just started. Consider one slice interval */ | |
949 | if (!jiffy_elapsed) | |
297e3d85 | 950 | jiffy_elapsed_rnd = tg->td->throtl_slice; |
e43473b7 | 951 | |
297e3d85 | 952 | jiffy_elapsed_rnd = roundup(jiffy_elapsed_rnd, tg->td->throtl_slice); |
e43473b7 | 953 | |
9f626e37 | 954 | tmp = tg_bps_limit(tg, rw) * jiffy_elapsed_rnd; |
5e901a2b | 955 | do_div(tmp, HZ); |
3aad5d3e | 956 | bytes_allowed = tmp; |
e43473b7 | 957 | |
ea0ea2bc | 958 | if (tg->bytes_disp[rw] + bio_size <= bytes_allowed) { |
e43473b7 VG |
959 | if (wait) |
960 | *wait = 0; | |
5cf8c227 | 961 | return true; |
e43473b7 VG |
962 | } |
963 | ||
964 | /* Calc approx time to dispatch */ | |
ea0ea2bc | 965 | extra_bytes = tg->bytes_disp[rw] + bio_size - bytes_allowed; |
9f626e37 | 966 | jiffy_wait = div64_u64(extra_bytes * HZ, tg_bps_limit(tg, rw)); |
e43473b7 VG |
967 | |
968 | if (!jiffy_wait) | |
969 | jiffy_wait = 1; | |
970 | ||
971 | /* | |
972 | * This wait time is without taking into consideration the rounding | |
973 | * up we did. Add that time also. | |
974 | */ | |
975 | jiffy_wait = jiffy_wait + (jiffy_elapsed_rnd - jiffy_elapsed); | |
e43473b7 VG |
976 | if (wait) |
977 | *wait = jiffy_wait; | |
0b6bad7d | 978 | return false; |
8e89d13f VG |
979 | } |
980 | ||
981 | /* | |
982 | * Returns whether one can dispatch a bio or not. Also returns approx number | |
983 | * of jiffies to wait before this bio is with-in IO rate and can be dispatched | |
984 | */ | |
0f3457f6 TH |
985 | static bool tg_may_dispatch(struct throtl_grp *tg, struct bio *bio, |
986 | unsigned long *wait) | |
8e89d13f VG |
987 | { |
988 | bool rw = bio_data_dir(bio); | |
989 | unsigned long bps_wait = 0, iops_wait = 0, max_wait = 0; | |
990 | ||
991 | /* | |
992 | * Currently whole state machine of group depends on first bio | |
993 | * queued in the group bio list. So one should not be calling | |
994 | * this function with a different bio if there are other bios | |
995 | * queued. | |
996 | */ | |
73f0d49a | 997 | BUG_ON(tg->service_queue.nr_queued[rw] && |
c5cc2070 | 998 | bio != throtl_peek_queued(&tg->service_queue.queued[rw])); |
e43473b7 | 999 | |
8e89d13f | 1000 | /* If tg->bps = -1, then BW is unlimited */ |
9f626e37 SL |
1001 | if (tg_bps_limit(tg, rw) == U64_MAX && |
1002 | tg_iops_limit(tg, rw) == UINT_MAX) { | |
8e89d13f VG |
1003 | if (wait) |
1004 | *wait = 0; | |
5cf8c227 | 1005 | return true; |
8e89d13f VG |
1006 | } |
1007 | ||
1008 | /* | |
1009 | * If previous slice expired, start a new one otherwise renew/extend | |
1010 | * existing slice to make sure it is at least throtl_slice interval | |
164c80ed VG |
1011 | * long since now. New slice is started only for empty throttle group. |
1012 | * If there is queued bio, that means there should be an active | |
1013 | * slice and it should be extended instead. | |
8e89d13f | 1014 | */ |
164c80ed | 1015 | if (throtl_slice_used(tg, rw) && !(tg->service_queue.nr_queued[rw])) |
0f3457f6 | 1016 | throtl_start_new_slice(tg, rw); |
8e89d13f | 1017 | else { |
297e3d85 SL |
1018 | if (time_before(tg->slice_end[rw], |
1019 | jiffies + tg->td->throtl_slice)) | |
1020 | throtl_extend_slice(tg, rw, | |
1021 | jiffies + tg->td->throtl_slice); | |
8e89d13f VG |
1022 | } |
1023 | ||
0f3457f6 TH |
1024 | if (tg_with_in_bps_limit(tg, bio, &bps_wait) && |
1025 | tg_with_in_iops_limit(tg, bio, &iops_wait)) { | |
8e89d13f VG |
1026 | if (wait) |
1027 | *wait = 0; | |
0b6bad7d | 1028 | return true; |
8e89d13f VG |
1029 | } |
1030 | ||
1031 | max_wait = max(bps_wait, iops_wait); | |
1032 | ||
1033 | if (wait) | |
1034 | *wait = max_wait; | |
1035 | ||
1036 | if (time_before(tg->slice_end[rw], jiffies + max_wait)) | |
0f3457f6 | 1037 | throtl_extend_slice(tg, rw, jiffies + max_wait); |
e43473b7 | 1038 | |
0b6bad7d | 1039 | return false; |
e43473b7 VG |
1040 | } |
1041 | ||
1042 | static void throtl_charge_bio(struct throtl_grp *tg, struct bio *bio) | |
1043 | { | |
1044 | bool rw = bio_data_dir(bio); | |
ea0ea2bc | 1045 | unsigned int bio_size = throtl_bio_data_size(bio); |
e43473b7 VG |
1046 | |
1047 | /* Charge the bio to the group */ | |
ea0ea2bc | 1048 | tg->bytes_disp[rw] += bio_size; |
8e89d13f | 1049 | tg->io_disp[rw]++; |
ea0ea2bc | 1050 | tg->last_bytes_disp[rw] += bio_size; |
3f0abd80 | 1051 | tg->last_io_disp[rw]++; |
e43473b7 | 1052 | |
2a0f61e6 | 1053 | /* |
8d2bbd4c | 1054 | * BIO_THROTTLED is used to prevent the same bio to be throttled |
2a0f61e6 TH |
1055 | * more than once as a throttled bio will go through blk-throtl the |
1056 | * second time when it eventually gets issued. Set it when a bio | |
1057 | * is being charged to a tg. | |
2a0f61e6 | 1058 | */ |
8d2bbd4c CH |
1059 | if (!bio_flagged(bio, BIO_THROTTLED)) |
1060 | bio_set_flag(bio, BIO_THROTTLED); | |
e43473b7 VG |
1061 | } |
1062 | ||
c5cc2070 TH |
1063 | /** |
1064 | * throtl_add_bio_tg - add a bio to the specified throtl_grp | |
1065 | * @bio: bio to add | |
1066 | * @qn: qnode to use | |
1067 | * @tg: the target throtl_grp | |
1068 | * | |
1069 | * Add @bio to @tg's service_queue using @qn. If @qn is not specified, | |
1070 | * tg->qnode_on_self[] is used. | |
1071 | */ | |
1072 | static void throtl_add_bio_tg(struct bio *bio, struct throtl_qnode *qn, | |
1073 | struct throtl_grp *tg) | |
e43473b7 | 1074 | { |
73f0d49a | 1075 | struct throtl_service_queue *sq = &tg->service_queue; |
e43473b7 VG |
1076 | bool rw = bio_data_dir(bio); |
1077 | ||
c5cc2070 TH |
1078 | if (!qn) |
1079 | qn = &tg->qnode_on_self[rw]; | |
1080 | ||
0e9f4164 TH |
1081 | /* |
1082 | * If @tg doesn't currently have any bios queued in the same | |
1083 | * direction, queueing @bio can change when @tg should be | |
1084 | * dispatched. Mark that @tg was empty. This is automatically | |
1085 | * cleaered on the next tg_update_disptime(). | |
1086 | */ | |
1087 | if (!sq->nr_queued[rw]) | |
1088 | tg->flags |= THROTL_TG_WAS_EMPTY; | |
1089 | ||
c5cc2070 TH |
1090 | throtl_qnode_add_bio(bio, qn, &sq->queued[rw]); |
1091 | ||
73f0d49a | 1092 | sq->nr_queued[rw]++; |
77216b04 | 1093 | throtl_enqueue_tg(tg); |
e43473b7 VG |
1094 | } |
1095 | ||
77216b04 | 1096 | static void tg_update_disptime(struct throtl_grp *tg) |
e43473b7 | 1097 | { |
73f0d49a | 1098 | struct throtl_service_queue *sq = &tg->service_queue; |
e43473b7 VG |
1099 | unsigned long read_wait = -1, write_wait = -1, min_wait = -1, disptime; |
1100 | struct bio *bio; | |
1101 | ||
d609af3a ME |
1102 | bio = throtl_peek_queued(&sq->queued[READ]); |
1103 | if (bio) | |
0f3457f6 | 1104 | tg_may_dispatch(tg, bio, &read_wait); |
e43473b7 | 1105 | |
d609af3a ME |
1106 | bio = throtl_peek_queued(&sq->queued[WRITE]); |
1107 | if (bio) | |
0f3457f6 | 1108 | tg_may_dispatch(tg, bio, &write_wait); |
e43473b7 VG |
1109 | |
1110 | min_wait = min(read_wait, write_wait); | |
1111 | disptime = jiffies + min_wait; | |
1112 | ||
e43473b7 | 1113 | /* Update dispatch time */ |
77216b04 | 1114 | throtl_dequeue_tg(tg); |
e43473b7 | 1115 | tg->disptime = disptime; |
77216b04 | 1116 | throtl_enqueue_tg(tg); |
0e9f4164 TH |
1117 | |
1118 | /* see throtl_add_bio_tg() */ | |
1119 | tg->flags &= ~THROTL_TG_WAS_EMPTY; | |
e43473b7 VG |
1120 | } |
1121 | ||
32ee5bc4 VG |
1122 | static void start_parent_slice_with_credit(struct throtl_grp *child_tg, |
1123 | struct throtl_grp *parent_tg, bool rw) | |
1124 | { | |
1125 | if (throtl_slice_used(parent_tg, rw)) { | |
1126 | throtl_start_new_slice_with_credit(parent_tg, rw, | |
1127 | child_tg->slice_start[rw]); | |
1128 | } | |
1129 | ||
1130 | } | |
1131 | ||
77216b04 | 1132 | static void tg_dispatch_one_bio(struct throtl_grp *tg, bool rw) |
e43473b7 | 1133 | { |
73f0d49a | 1134 | struct throtl_service_queue *sq = &tg->service_queue; |
6bc9c2b4 TH |
1135 | struct throtl_service_queue *parent_sq = sq->parent_sq; |
1136 | struct throtl_grp *parent_tg = sq_to_tg(parent_sq); | |
c5cc2070 | 1137 | struct throtl_grp *tg_to_put = NULL; |
e43473b7 VG |
1138 | struct bio *bio; |
1139 | ||
c5cc2070 TH |
1140 | /* |
1141 | * @bio is being transferred from @tg to @parent_sq. Popping a bio | |
1142 | * from @tg may put its reference and @parent_sq might end up | |
1143 | * getting released prematurely. Remember the tg to put and put it | |
1144 | * after @bio is transferred to @parent_sq. | |
1145 | */ | |
1146 | bio = throtl_pop_queued(&sq->queued[rw], &tg_to_put); | |
73f0d49a | 1147 | sq->nr_queued[rw]--; |
e43473b7 VG |
1148 | |
1149 | throtl_charge_bio(tg, bio); | |
6bc9c2b4 TH |
1150 | |
1151 | /* | |
1152 | * If our parent is another tg, we just need to transfer @bio to | |
1153 | * the parent using throtl_add_bio_tg(). If our parent is | |
1154 | * @td->service_queue, @bio is ready to be issued. Put it on its | |
1155 | * bio_lists[] and decrease total number queued. The caller is | |
1156 | * responsible for issuing these bios. | |
1157 | */ | |
1158 | if (parent_tg) { | |
c5cc2070 | 1159 | throtl_add_bio_tg(bio, &tg->qnode_on_parent[rw], parent_tg); |
32ee5bc4 | 1160 | start_parent_slice_with_credit(tg, parent_tg, rw); |
6bc9c2b4 | 1161 | } else { |
c5cc2070 TH |
1162 | throtl_qnode_add_bio(bio, &tg->qnode_on_parent[rw], |
1163 | &parent_sq->queued[rw]); | |
6bc9c2b4 TH |
1164 | BUG_ON(tg->td->nr_queued[rw] <= 0); |
1165 | tg->td->nr_queued[rw]--; | |
1166 | } | |
e43473b7 | 1167 | |
0f3457f6 | 1168 | throtl_trim_slice(tg, rw); |
6bc9c2b4 | 1169 | |
c5cc2070 TH |
1170 | if (tg_to_put) |
1171 | blkg_put(tg_to_blkg(tg_to_put)); | |
e43473b7 VG |
1172 | } |
1173 | ||
77216b04 | 1174 | static int throtl_dispatch_tg(struct throtl_grp *tg) |
e43473b7 | 1175 | { |
73f0d49a | 1176 | struct throtl_service_queue *sq = &tg->service_queue; |
e43473b7 VG |
1177 | unsigned int nr_reads = 0, nr_writes = 0; |
1178 | unsigned int max_nr_reads = throtl_grp_quantum*3/4; | |
c2f6805d | 1179 | unsigned int max_nr_writes = throtl_grp_quantum - max_nr_reads; |
e43473b7 VG |
1180 | struct bio *bio; |
1181 | ||
1182 | /* Try to dispatch 75% READS and 25% WRITES */ | |
1183 | ||
c5cc2070 | 1184 | while ((bio = throtl_peek_queued(&sq->queued[READ])) && |
0f3457f6 | 1185 | tg_may_dispatch(tg, bio, NULL)) { |
e43473b7 | 1186 | |
77216b04 | 1187 | tg_dispatch_one_bio(tg, bio_data_dir(bio)); |
e43473b7 VG |
1188 | nr_reads++; |
1189 | ||
1190 | if (nr_reads >= max_nr_reads) | |
1191 | break; | |
1192 | } | |
1193 | ||
c5cc2070 | 1194 | while ((bio = throtl_peek_queued(&sq->queued[WRITE])) && |
0f3457f6 | 1195 | tg_may_dispatch(tg, bio, NULL)) { |
e43473b7 | 1196 | |
77216b04 | 1197 | tg_dispatch_one_bio(tg, bio_data_dir(bio)); |
e43473b7 VG |
1198 | nr_writes++; |
1199 | ||
1200 | if (nr_writes >= max_nr_writes) | |
1201 | break; | |
1202 | } | |
1203 | ||
1204 | return nr_reads + nr_writes; | |
1205 | } | |
1206 | ||
651930bc | 1207 | static int throtl_select_dispatch(struct throtl_service_queue *parent_sq) |
e43473b7 VG |
1208 | { |
1209 | unsigned int nr_disp = 0; | |
e43473b7 VG |
1210 | |
1211 | while (1) { | |
73f0d49a | 1212 | struct throtl_grp *tg = throtl_rb_first(parent_sq); |
2ab74cd2 | 1213 | struct throtl_service_queue *sq; |
e43473b7 VG |
1214 | |
1215 | if (!tg) | |
1216 | break; | |
1217 | ||
1218 | if (time_before(jiffies, tg->disptime)) | |
1219 | break; | |
1220 | ||
77216b04 | 1221 | throtl_dequeue_tg(tg); |
e43473b7 | 1222 | |
77216b04 | 1223 | nr_disp += throtl_dispatch_tg(tg); |
e43473b7 | 1224 | |
2ab74cd2 | 1225 | sq = &tg->service_queue; |
73f0d49a | 1226 | if (sq->nr_queued[0] || sq->nr_queued[1]) |
77216b04 | 1227 | tg_update_disptime(tg); |
e43473b7 VG |
1228 | |
1229 | if (nr_disp >= throtl_quantum) | |
1230 | break; | |
1231 | } | |
1232 | ||
1233 | return nr_disp; | |
1234 | } | |
1235 | ||
c79892c5 SL |
1236 | static bool throtl_can_upgrade(struct throtl_data *td, |
1237 | struct throtl_grp *this_tg); | |
6e1a5704 TH |
1238 | /** |
1239 | * throtl_pending_timer_fn - timer function for service_queue->pending_timer | |
216382dc | 1240 | * @t: the pending_timer member of the throtl_service_queue being serviced |
6e1a5704 TH |
1241 | * |
1242 | * This timer is armed when a child throtl_grp with active bio's become | |
1243 | * pending and queued on the service_queue's pending_tree and expires when | |
1244 | * the first child throtl_grp should be dispatched. This function | |
2e48a530 TH |
1245 | * dispatches bio's from the children throtl_grps to the parent |
1246 | * service_queue. | |
1247 | * | |
1248 | * If the parent's parent is another throtl_grp, dispatching is propagated | |
1249 | * by either arming its pending_timer or repeating dispatch directly. If | |
1250 | * the top-level service_tree is reached, throtl_data->dispatch_work is | |
1251 | * kicked so that the ready bio's are issued. | |
6e1a5704 | 1252 | */ |
e99e88a9 | 1253 | static void throtl_pending_timer_fn(struct timer_list *t) |
69df0ab0 | 1254 | { |
e99e88a9 | 1255 | struct throtl_service_queue *sq = from_timer(sq, t, pending_timer); |
2e48a530 | 1256 | struct throtl_grp *tg = sq_to_tg(sq); |
69df0ab0 | 1257 | struct throtl_data *td = sq_to_td(sq); |
cb76199c | 1258 | struct request_queue *q = td->queue; |
2e48a530 TH |
1259 | struct throtl_service_queue *parent_sq; |
1260 | bool dispatched; | |
6e1a5704 | 1261 | int ret; |
e43473b7 | 1262 | |
0d945c1f | 1263 | spin_lock_irq(&q->queue_lock); |
c79892c5 SL |
1264 | if (throtl_can_upgrade(td, NULL)) |
1265 | throtl_upgrade_state(td); | |
1266 | ||
2e48a530 TH |
1267 | again: |
1268 | parent_sq = sq->parent_sq; | |
1269 | dispatched = false; | |
e43473b7 | 1270 | |
7f52f98c TH |
1271 | while (true) { |
1272 | throtl_log(sq, "dispatch nr_queued=%u read=%u write=%u", | |
2e48a530 TH |
1273 | sq->nr_queued[READ] + sq->nr_queued[WRITE], |
1274 | sq->nr_queued[READ], sq->nr_queued[WRITE]); | |
7f52f98c TH |
1275 | |
1276 | ret = throtl_select_dispatch(sq); | |
1277 | if (ret) { | |
7f52f98c TH |
1278 | throtl_log(sq, "bios disp=%u", ret); |
1279 | dispatched = true; | |
1280 | } | |
e43473b7 | 1281 | |
7f52f98c TH |
1282 | if (throtl_schedule_next_dispatch(sq, false)) |
1283 | break; | |
e43473b7 | 1284 | |
7f52f98c | 1285 | /* this dispatch windows is still open, relax and repeat */ |
0d945c1f | 1286 | spin_unlock_irq(&q->queue_lock); |
7f52f98c | 1287 | cpu_relax(); |
0d945c1f | 1288 | spin_lock_irq(&q->queue_lock); |
651930bc | 1289 | } |
e43473b7 | 1290 | |
2e48a530 TH |
1291 | if (!dispatched) |
1292 | goto out_unlock; | |
6e1a5704 | 1293 | |
2e48a530 TH |
1294 | if (parent_sq) { |
1295 | /* @parent_sq is another throl_grp, propagate dispatch */ | |
1296 | if (tg->flags & THROTL_TG_WAS_EMPTY) { | |
1297 | tg_update_disptime(tg); | |
1298 | if (!throtl_schedule_next_dispatch(parent_sq, false)) { | |
1299 | /* window is already open, repeat dispatching */ | |
1300 | sq = parent_sq; | |
1301 | tg = sq_to_tg(sq); | |
1302 | goto again; | |
1303 | } | |
1304 | } | |
1305 | } else { | |
1306 | /* reached the top-level, queue issueing */ | |
1307 | queue_work(kthrotld_workqueue, &td->dispatch_work); | |
1308 | } | |
1309 | out_unlock: | |
0d945c1f | 1310 | spin_unlock_irq(&q->queue_lock); |
6e1a5704 | 1311 | } |
e43473b7 | 1312 | |
6e1a5704 TH |
1313 | /** |
1314 | * blk_throtl_dispatch_work_fn - work function for throtl_data->dispatch_work | |
1315 | * @work: work item being executed | |
1316 | * | |
1317 | * This function is queued for execution when bio's reach the bio_lists[] | |
1318 | * of throtl_data->service_queue. Those bio's are ready and issued by this | |
1319 | * function. | |
1320 | */ | |
8876e140 | 1321 | static void blk_throtl_dispatch_work_fn(struct work_struct *work) |
6e1a5704 TH |
1322 | { |
1323 | struct throtl_data *td = container_of(work, struct throtl_data, | |
1324 | dispatch_work); | |
1325 | struct throtl_service_queue *td_sq = &td->service_queue; | |
1326 | struct request_queue *q = td->queue; | |
1327 | struct bio_list bio_list_on_stack; | |
1328 | struct bio *bio; | |
1329 | struct blk_plug plug; | |
1330 | int rw; | |
1331 | ||
1332 | bio_list_init(&bio_list_on_stack); | |
1333 | ||
0d945c1f | 1334 | spin_lock_irq(&q->queue_lock); |
c5cc2070 TH |
1335 | for (rw = READ; rw <= WRITE; rw++) |
1336 | while ((bio = throtl_pop_queued(&td_sq->queued[rw], NULL))) | |
1337 | bio_list_add(&bio_list_on_stack, bio); | |
0d945c1f | 1338 | spin_unlock_irq(&q->queue_lock); |
6e1a5704 TH |
1339 | |
1340 | if (!bio_list_empty(&bio_list_on_stack)) { | |
69d60eb9 | 1341 | blk_start_plug(&plug); |
e43473b7 VG |
1342 | while((bio = bio_list_pop(&bio_list_on_stack))) |
1343 | generic_make_request(bio); | |
69d60eb9 | 1344 | blk_finish_plug(&plug); |
e43473b7 | 1345 | } |
e43473b7 VG |
1346 | } |
1347 | ||
f95a04af TH |
1348 | static u64 tg_prfill_conf_u64(struct seq_file *sf, struct blkg_policy_data *pd, |
1349 | int off) | |
60c2bc2d | 1350 | { |
f95a04af TH |
1351 | struct throtl_grp *tg = pd_to_tg(pd); |
1352 | u64 v = *(u64 *)((void *)tg + off); | |
60c2bc2d | 1353 | |
2ab5492d | 1354 | if (v == U64_MAX) |
60c2bc2d | 1355 | return 0; |
f95a04af | 1356 | return __blkg_prfill_u64(sf, pd, v); |
60c2bc2d TH |
1357 | } |
1358 | ||
f95a04af TH |
1359 | static u64 tg_prfill_conf_uint(struct seq_file *sf, struct blkg_policy_data *pd, |
1360 | int off) | |
e43473b7 | 1361 | { |
f95a04af TH |
1362 | struct throtl_grp *tg = pd_to_tg(pd); |
1363 | unsigned int v = *(unsigned int *)((void *)tg + off); | |
fe071437 | 1364 | |
2ab5492d | 1365 | if (v == UINT_MAX) |
af133ceb | 1366 | return 0; |
f95a04af | 1367 | return __blkg_prfill_u64(sf, pd, v); |
e43473b7 VG |
1368 | } |
1369 | ||
2da8ca82 | 1370 | static int tg_print_conf_u64(struct seq_file *sf, void *v) |
8e89d13f | 1371 | { |
2da8ca82 TH |
1372 | blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), tg_prfill_conf_u64, |
1373 | &blkcg_policy_throtl, seq_cft(sf)->private, false); | |
af133ceb | 1374 | return 0; |
8e89d13f VG |
1375 | } |
1376 | ||
2da8ca82 | 1377 | static int tg_print_conf_uint(struct seq_file *sf, void *v) |
8e89d13f | 1378 | { |
2da8ca82 TH |
1379 | blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), tg_prfill_conf_uint, |
1380 | &blkcg_policy_throtl, seq_cft(sf)->private, false); | |
af133ceb | 1381 | return 0; |
60c2bc2d TH |
1382 | } |
1383 | ||
9bb67aeb | 1384 | static void tg_conf_updated(struct throtl_grp *tg, bool global) |
60c2bc2d | 1385 | { |
69948b07 | 1386 | struct throtl_service_queue *sq = &tg->service_queue; |
492eb21b | 1387 | struct cgroup_subsys_state *pos_css; |
69948b07 | 1388 | struct blkcg_gq *blkg; |
af133ceb | 1389 | |
fda6f272 TH |
1390 | throtl_log(&tg->service_queue, |
1391 | "limit change rbps=%llu wbps=%llu riops=%u wiops=%u", | |
9f626e37 SL |
1392 | tg_bps_limit(tg, READ), tg_bps_limit(tg, WRITE), |
1393 | tg_iops_limit(tg, READ), tg_iops_limit(tg, WRITE)); | |
632b4493 | 1394 | |
693e751e TH |
1395 | /* |
1396 | * Update has_rules[] flags for the updated tg's subtree. A tg is | |
1397 | * considered to have rules if either the tg itself or any of its | |
1398 | * ancestors has rules. This identifies groups without any | |
1399 | * restrictions in the whole hierarchy and allows them to bypass | |
1400 | * blk-throttle. | |
1401 | */ | |
9bb67aeb SL |
1402 | blkg_for_each_descendant_pre(blkg, pos_css, |
1403 | global ? tg->td->queue->root_blkg : tg_to_blkg(tg)) { | |
5b81fc3c SL |
1404 | struct throtl_grp *this_tg = blkg_to_tg(blkg); |
1405 | struct throtl_grp *parent_tg; | |
1406 | ||
1407 | tg_update_has_rules(this_tg); | |
1408 | /* ignore root/second level */ | |
1409 | if (!cgroup_subsys_on_dfl(io_cgrp_subsys) || !blkg->parent || | |
1410 | !blkg->parent->parent) | |
1411 | continue; | |
1412 | parent_tg = blkg_to_tg(blkg->parent); | |
1413 | /* | |
1414 | * make sure all children has lower idle time threshold and | |
1415 | * higher latency target | |
1416 | */ | |
1417 | this_tg->idletime_threshold = min(this_tg->idletime_threshold, | |
1418 | parent_tg->idletime_threshold); | |
1419 | this_tg->latency_target = max(this_tg->latency_target, | |
1420 | parent_tg->latency_target); | |
1421 | } | |
693e751e | 1422 | |
632b4493 TH |
1423 | /* |
1424 | * We're already holding queue_lock and know @tg is valid. Let's | |
1425 | * apply the new config directly. | |
1426 | * | |
1427 | * Restart the slices for both READ and WRITES. It might happen | |
1428 | * that a group's limit are dropped suddenly and we don't want to | |
1429 | * account recently dispatched IO with new low rate. | |
1430 | */ | |
0f3457f6 TH |
1431 | throtl_start_new_slice(tg, 0); |
1432 | throtl_start_new_slice(tg, 1); | |
632b4493 | 1433 | |
5b2c16aa | 1434 | if (tg->flags & THROTL_TG_PENDING) { |
77216b04 | 1435 | tg_update_disptime(tg); |
7f52f98c | 1436 | throtl_schedule_next_dispatch(sq->parent_sq, true); |
632b4493 | 1437 | } |
69948b07 TH |
1438 | } |
1439 | ||
1440 | static ssize_t tg_set_conf(struct kernfs_open_file *of, | |
1441 | char *buf, size_t nbytes, loff_t off, bool is_u64) | |
1442 | { | |
1443 | struct blkcg *blkcg = css_to_blkcg(of_css(of)); | |
1444 | struct blkg_conf_ctx ctx; | |
1445 | struct throtl_grp *tg; | |
1446 | int ret; | |
1447 | u64 v; | |
1448 | ||
1449 | ret = blkg_conf_prep(blkcg, &blkcg_policy_throtl, buf, &ctx); | |
1450 | if (ret) | |
1451 | return ret; | |
1452 | ||
1453 | ret = -EINVAL; | |
1454 | if (sscanf(ctx.body, "%llu", &v) != 1) | |
1455 | goto out_finish; | |
1456 | if (!v) | |
2ab5492d | 1457 | v = U64_MAX; |
69948b07 TH |
1458 | |
1459 | tg = blkg_to_tg(ctx.blkg); | |
1460 | ||
1461 | if (is_u64) | |
1462 | *(u64 *)((void *)tg + of_cft(of)->private) = v; | |
1463 | else | |
1464 | *(unsigned int *)((void *)tg + of_cft(of)->private) = v; | |
60c2bc2d | 1465 | |
9bb67aeb | 1466 | tg_conf_updated(tg, false); |
36aa9e5f TH |
1467 | ret = 0; |
1468 | out_finish: | |
60c2bc2d | 1469 | blkg_conf_finish(&ctx); |
36aa9e5f | 1470 | return ret ?: nbytes; |
8e89d13f VG |
1471 | } |
1472 | ||
451af504 TH |
1473 | static ssize_t tg_set_conf_u64(struct kernfs_open_file *of, |
1474 | char *buf, size_t nbytes, loff_t off) | |
60c2bc2d | 1475 | { |
451af504 | 1476 | return tg_set_conf(of, buf, nbytes, off, true); |
60c2bc2d TH |
1477 | } |
1478 | ||
451af504 TH |
1479 | static ssize_t tg_set_conf_uint(struct kernfs_open_file *of, |
1480 | char *buf, size_t nbytes, loff_t off) | |
60c2bc2d | 1481 | { |
451af504 | 1482 | return tg_set_conf(of, buf, nbytes, off, false); |
60c2bc2d TH |
1483 | } |
1484 | ||
7ca46438 TH |
1485 | static int tg_print_rwstat(struct seq_file *sf, void *v) |
1486 | { | |
1487 | blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), | |
1488 | blkg_prfill_rwstat, &blkcg_policy_throtl, | |
1489 | seq_cft(sf)->private, true); | |
1490 | return 0; | |
1491 | } | |
1492 | ||
1493 | static u64 tg_prfill_rwstat_recursive(struct seq_file *sf, | |
1494 | struct blkg_policy_data *pd, int off) | |
1495 | { | |
1496 | struct blkg_rwstat_sample sum; | |
1497 | ||
1498 | blkg_rwstat_recursive_sum(pd_to_blkg(pd), &blkcg_policy_throtl, off, | |
1499 | &sum); | |
1500 | return __blkg_prfill_rwstat(sf, pd, &sum); | |
1501 | } | |
1502 | ||
1503 | static int tg_print_rwstat_recursive(struct seq_file *sf, void *v) | |
1504 | { | |
1505 | blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), | |
1506 | tg_prfill_rwstat_recursive, &blkcg_policy_throtl, | |
1507 | seq_cft(sf)->private, true); | |
1508 | return 0; | |
1509 | } | |
1510 | ||
880f50e2 | 1511 | static struct cftype throtl_legacy_files[] = { |
60c2bc2d TH |
1512 | { |
1513 | .name = "throttle.read_bps_device", | |
9f626e37 | 1514 | .private = offsetof(struct throtl_grp, bps[READ][LIMIT_MAX]), |
2da8ca82 | 1515 | .seq_show = tg_print_conf_u64, |
451af504 | 1516 | .write = tg_set_conf_u64, |
60c2bc2d TH |
1517 | }, |
1518 | { | |
1519 | .name = "throttle.write_bps_device", | |
9f626e37 | 1520 | .private = offsetof(struct throtl_grp, bps[WRITE][LIMIT_MAX]), |
2da8ca82 | 1521 | .seq_show = tg_print_conf_u64, |
451af504 | 1522 | .write = tg_set_conf_u64, |
60c2bc2d TH |
1523 | }, |
1524 | { | |
1525 | .name = "throttle.read_iops_device", | |
9f626e37 | 1526 | .private = offsetof(struct throtl_grp, iops[READ][LIMIT_MAX]), |
2da8ca82 | 1527 | .seq_show = tg_print_conf_uint, |
451af504 | 1528 | .write = tg_set_conf_uint, |
60c2bc2d TH |
1529 | }, |
1530 | { | |
1531 | .name = "throttle.write_iops_device", | |
9f626e37 | 1532 | .private = offsetof(struct throtl_grp, iops[WRITE][LIMIT_MAX]), |
2da8ca82 | 1533 | .seq_show = tg_print_conf_uint, |
451af504 | 1534 | .write = tg_set_conf_uint, |
60c2bc2d TH |
1535 | }, |
1536 | { | |
1537 | .name = "throttle.io_service_bytes", | |
7ca46438 TH |
1538 | .private = offsetof(struct throtl_grp, stat_bytes), |
1539 | .seq_show = tg_print_rwstat, | |
60c2bc2d | 1540 | }, |
17534c6f | 1541 | { |
1542 | .name = "throttle.io_service_bytes_recursive", | |
7ca46438 TH |
1543 | .private = offsetof(struct throtl_grp, stat_bytes), |
1544 | .seq_show = tg_print_rwstat_recursive, | |
17534c6f | 1545 | }, |
60c2bc2d TH |
1546 | { |
1547 | .name = "throttle.io_serviced", | |
7ca46438 TH |
1548 | .private = offsetof(struct throtl_grp, stat_ios), |
1549 | .seq_show = tg_print_rwstat, | |
60c2bc2d | 1550 | }, |
17534c6f | 1551 | { |
1552 | .name = "throttle.io_serviced_recursive", | |
7ca46438 TH |
1553 | .private = offsetof(struct throtl_grp, stat_ios), |
1554 | .seq_show = tg_print_rwstat_recursive, | |
17534c6f | 1555 | }, |
60c2bc2d TH |
1556 | { } /* terminate */ |
1557 | }; | |
1558 | ||
cd5ab1b0 | 1559 | static u64 tg_prfill_limit(struct seq_file *sf, struct blkg_policy_data *pd, |
2ee867dc TH |
1560 | int off) |
1561 | { | |
1562 | struct throtl_grp *tg = pd_to_tg(pd); | |
1563 | const char *dname = blkg_dev_name(pd->blkg); | |
1564 | char bufs[4][21] = { "max", "max", "max", "max" }; | |
cd5ab1b0 SL |
1565 | u64 bps_dft; |
1566 | unsigned int iops_dft; | |
ada75b6e | 1567 | char idle_time[26] = ""; |
ec80991d | 1568 | char latency_time[26] = ""; |
2ee867dc TH |
1569 | |
1570 | if (!dname) | |
1571 | return 0; | |
9f626e37 | 1572 | |
cd5ab1b0 SL |
1573 | if (off == LIMIT_LOW) { |
1574 | bps_dft = 0; | |
1575 | iops_dft = 0; | |
1576 | } else { | |
1577 | bps_dft = U64_MAX; | |
1578 | iops_dft = UINT_MAX; | |
1579 | } | |
1580 | ||
1581 | if (tg->bps_conf[READ][off] == bps_dft && | |
1582 | tg->bps_conf[WRITE][off] == bps_dft && | |
1583 | tg->iops_conf[READ][off] == iops_dft && | |
ada75b6e | 1584 | tg->iops_conf[WRITE][off] == iops_dft && |
ec80991d | 1585 | (off != LIMIT_LOW || |
b4f428ef | 1586 | (tg->idletime_threshold_conf == DFL_IDLE_THRESHOLD && |
5b81fc3c | 1587 | tg->latency_target_conf == DFL_LATENCY_TARGET))) |
2ee867dc TH |
1588 | return 0; |
1589 | ||
9bb67aeb | 1590 | if (tg->bps_conf[READ][off] != U64_MAX) |
9f626e37 | 1591 | snprintf(bufs[0], sizeof(bufs[0]), "%llu", |
cd5ab1b0 | 1592 | tg->bps_conf[READ][off]); |
9bb67aeb | 1593 | if (tg->bps_conf[WRITE][off] != U64_MAX) |
9f626e37 | 1594 | snprintf(bufs[1], sizeof(bufs[1]), "%llu", |
cd5ab1b0 | 1595 | tg->bps_conf[WRITE][off]); |
9bb67aeb | 1596 | if (tg->iops_conf[READ][off] != UINT_MAX) |
9f626e37 | 1597 | snprintf(bufs[2], sizeof(bufs[2]), "%u", |
cd5ab1b0 | 1598 | tg->iops_conf[READ][off]); |
9bb67aeb | 1599 | if (tg->iops_conf[WRITE][off] != UINT_MAX) |
9f626e37 | 1600 | snprintf(bufs[3], sizeof(bufs[3]), "%u", |
cd5ab1b0 | 1601 | tg->iops_conf[WRITE][off]); |
ada75b6e | 1602 | if (off == LIMIT_LOW) { |
5b81fc3c | 1603 | if (tg->idletime_threshold_conf == ULONG_MAX) |
ada75b6e SL |
1604 | strcpy(idle_time, " idle=max"); |
1605 | else | |
1606 | snprintf(idle_time, sizeof(idle_time), " idle=%lu", | |
5b81fc3c | 1607 | tg->idletime_threshold_conf); |
ec80991d | 1608 | |
5b81fc3c | 1609 | if (tg->latency_target_conf == ULONG_MAX) |
ec80991d SL |
1610 | strcpy(latency_time, " latency=max"); |
1611 | else | |
1612 | snprintf(latency_time, sizeof(latency_time), | |
5b81fc3c | 1613 | " latency=%lu", tg->latency_target_conf); |
ada75b6e | 1614 | } |
2ee867dc | 1615 | |
ec80991d SL |
1616 | seq_printf(sf, "%s rbps=%s wbps=%s riops=%s wiops=%s%s%s\n", |
1617 | dname, bufs[0], bufs[1], bufs[2], bufs[3], idle_time, | |
1618 | latency_time); | |
2ee867dc TH |
1619 | return 0; |
1620 | } | |
1621 | ||
cd5ab1b0 | 1622 | static int tg_print_limit(struct seq_file *sf, void *v) |
2ee867dc | 1623 | { |
cd5ab1b0 | 1624 | blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), tg_prfill_limit, |
2ee867dc TH |
1625 | &blkcg_policy_throtl, seq_cft(sf)->private, false); |
1626 | return 0; | |
1627 | } | |
1628 | ||
cd5ab1b0 | 1629 | static ssize_t tg_set_limit(struct kernfs_open_file *of, |
2ee867dc TH |
1630 | char *buf, size_t nbytes, loff_t off) |
1631 | { | |
1632 | struct blkcg *blkcg = css_to_blkcg(of_css(of)); | |
1633 | struct blkg_conf_ctx ctx; | |
1634 | struct throtl_grp *tg; | |
1635 | u64 v[4]; | |
ada75b6e | 1636 | unsigned long idle_time; |
ec80991d | 1637 | unsigned long latency_time; |
2ee867dc | 1638 | int ret; |
cd5ab1b0 | 1639 | int index = of_cft(of)->private; |
2ee867dc TH |
1640 | |
1641 | ret = blkg_conf_prep(blkcg, &blkcg_policy_throtl, buf, &ctx); | |
1642 | if (ret) | |
1643 | return ret; | |
1644 | ||
1645 | tg = blkg_to_tg(ctx.blkg); | |
1646 | ||
cd5ab1b0 SL |
1647 | v[0] = tg->bps_conf[READ][index]; |
1648 | v[1] = tg->bps_conf[WRITE][index]; | |
1649 | v[2] = tg->iops_conf[READ][index]; | |
1650 | v[3] = tg->iops_conf[WRITE][index]; | |
2ee867dc | 1651 | |
5b81fc3c SL |
1652 | idle_time = tg->idletime_threshold_conf; |
1653 | latency_time = tg->latency_target_conf; | |
2ee867dc TH |
1654 | while (true) { |
1655 | char tok[27]; /* wiops=18446744073709551616 */ | |
1656 | char *p; | |
2ab5492d | 1657 | u64 val = U64_MAX; |
2ee867dc TH |
1658 | int len; |
1659 | ||
1660 | if (sscanf(ctx.body, "%26s%n", tok, &len) != 1) | |
1661 | break; | |
1662 | if (tok[0] == '\0') | |
1663 | break; | |
1664 | ctx.body += len; | |
1665 | ||
1666 | ret = -EINVAL; | |
1667 | p = tok; | |
1668 | strsep(&p, "="); | |
1669 | if (!p || (sscanf(p, "%llu", &val) != 1 && strcmp(p, "max"))) | |
1670 | goto out_finish; | |
1671 | ||
1672 | ret = -ERANGE; | |
1673 | if (!val) | |
1674 | goto out_finish; | |
1675 | ||
1676 | ret = -EINVAL; | |
1677 | if (!strcmp(tok, "rbps")) | |
1678 | v[0] = val; | |
1679 | else if (!strcmp(tok, "wbps")) | |
1680 | v[1] = val; | |
1681 | else if (!strcmp(tok, "riops")) | |
1682 | v[2] = min_t(u64, val, UINT_MAX); | |
1683 | else if (!strcmp(tok, "wiops")) | |
1684 | v[3] = min_t(u64, val, UINT_MAX); | |
ada75b6e SL |
1685 | else if (off == LIMIT_LOW && !strcmp(tok, "idle")) |
1686 | idle_time = val; | |
ec80991d SL |
1687 | else if (off == LIMIT_LOW && !strcmp(tok, "latency")) |
1688 | latency_time = val; | |
2ee867dc TH |
1689 | else |
1690 | goto out_finish; | |
1691 | } | |
1692 | ||
cd5ab1b0 SL |
1693 | tg->bps_conf[READ][index] = v[0]; |
1694 | tg->bps_conf[WRITE][index] = v[1]; | |
1695 | tg->iops_conf[READ][index] = v[2]; | |
1696 | tg->iops_conf[WRITE][index] = v[3]; | |
2ee867dc | 1697 | |
cd5ab1b0 SL |
1698 | if (index == LIMIT_MAX) { |
1699 | tg->bps[READ][index] = v[0]; | |
1700 | tg->bps[WRITE][index] = v[1]; | |
1701 | tg->iops[READ][index] = v[2]; | |
1702 | tg->iops[WRITE][index] = v[3]; | |
1703 | } | |
1704 | tg->bps[READ][LIMIT_LOW] = min(tg->bps_conf[READ][LIMIT_LOW], | |
1705 | tg->bps_conf[READ][LIMIT_MAX]); | |
1706 | tg->bps[WRITE][LIMIT_LOW] = min(tg->bps_conf[WRITE][LIMIT_LOW], | |
1707 | tg->bps_conf[WRITE][LIMIT_MAX]); | |
1708 | tg->iops[READ][LIMIT_LOW] = min(tg->iops_conf[READ][LIMIT_LOW], | |
1709 | tg->iops_conf[READ][LIMIT_MAX]); | |
1710 | tg->iops[WRITE][LIMIT_LOW] = min(tg->iops_conf[WRITE][LIMIT_LOW], | |
1711 | tg->iops_conf[WRITE][LIMIT_MAX]); | |
b4f428ef SL |
1712 | tg->idletime_threshold_conf = idle_time; |
1713 | tg->latency_target_conf = latency_time; | |
1714 | ||
1715 | /* force user to configure all settings for low limit */ | |
1716 | if (!(tg->bps[READ][LIMIT_LOW] || tg->iops[READ][LIMIT_LOW] || | |
1717 | tg->bps[WRITE][LIMIT_LOW] || tg->iops[WRITE][LIMIT_LOW]) || | |
1718 | tg->idletime_threshold_conf == DFL_IDLE_THRESHOLD || | |
1719 | tg->latency_target_conf == DFL_LATENCY_TARGET) { | |
1720 | tg->bps[READ][LIMIT_LOW] = 0; | |
1721 | tg->bps[WRITE][LIMIT_LOW] = 0; | |
1722 | tg->iops[READ][LIMIT_LOW] = 0; | |
1723 | tg->iops[WRITE][LIMIT_LOW] = 0; | |
1724 | tg->idletime_threshold = DFL_IDLE_THRESHOLD; | |
1725 | tg->latency_target = DFL_LATENCY_TARGET; | |
1726 | } else if (index == LIMIT_LOW) { | |
5b81fc3c | 1727 | tg->idletime_threshold = tg->idletime_threshold_conf; |
5b81fc3c | 1728 | tg->latency_target = tg->latency_target_conf; |
cd5ab1b0 | 1729 | } |
b4f428ef SL |
1730 | |
1731 | blk_throtl_update_limit_valid(tg->td); | |
1732 | if (tg->td->limit_valid[LIMIT_LOW]) { | |
1733 | if (index == LIMIT_LOW) | |
1734 | tg->td->limit_index = LIMIT_LOW; | |
1735 | } else | |
1736 | tg->td->limit_index = LIMIT_MAX; | |
9bb67aeb SL |
1737 | tg_conf_updated(tg, index == LIMIT_LOW && |
1738 | tg->td->limit_valid[LIMIT_LOW]); | |
2ee867dc TH |
1739 | ret = 0; |
1740 | out_finish: | |
1741 | blkg_conf_finish(&ctx); | |
1742 | return ret ?: nbytes; | |
1743 | } | |
1744 | ||
1745 | static struct cftype throtl_files[] = { | |
cd5ab1b0 SL |
1746 | #ifdef CONFIG_BLK_DEV_THROTTLING_LOW |
1747 | { | |
1748 | .name = "low", | |
1749 | .flags = CFTYPE_NOT_ON_ROOT, | |
1750 | .seq_show = tg_print_limit, | |
1751 | .write = tg_set_limit, | |
1752 | .private = LIMIT_LOW, | |
1753 | }, | |
1754 | #endif | |
2ee867dc TH |
1755 | { |
1756 | .name = "max", | |
1757 | .flags = CFTYPE_NOT_ON_ROOT, | |
cd5ab1b0 SL |
1758 | .seq_show = tg_print_limit, |
1759 | .write = tg_set_limit, | |
1760 | .private = LIMIT_MAX, | |
2ee867dc TH |
1761 | }, |
1762 | { } /* terminate */ | |
1763 | }; | |
1764 | ||
da527770 | 1765 | static void throtl_shutdown_wq(struct request_queue *q) |
e43473b7 VG |
1766 | { |
1767 | struct throtl_data *td = q->td; | |
1768 | ||
69df0ab0 | 1769 | cancel_work_sync(&td->dispatch_work); |
e43473b7 VG |
1770 | } |
1771 | ||
3c798398 | 1772 | static struct blkcg_policy blkcg_policy_throtl = { |
2ee867dc | 1773 | .dfl_cftypes = throtl_files, |
880f50e2 | 1774 | .legacy_cftypes = throtl_legacy_files, |
f9fcc2d3 | 1775 | |
001bea73 | 1776 | .pd_alloc_fn = throtl_pd_alloc, |
f9fcc2d3 | 1777 | .pd_init_fn = throtl_pd_init, |
693e751e | 1778 | .pd_online_fn = throtl_pd_online, |
cd5ab1b0 | 1779 | .pd_offline_fn = throtl_pd_offline, |
001bea73 | 1780 | .pd_free_fn = throtl_pd_free, |
e43473b7 VG |
1781 | }; |
1782 | ||
3f0abd80 SL |
1783 | static unsigned long __tg_last_low_overflow_time(struct throtl_grp *tg) |
1784 | { | |
1785 | unsigned long rtime = jiffies, wtime = jiffies; | |
1786 | ||
1787 | if (tg->bps[READ][LIMIT_LOW] || tg->iops[READ][LIMIT_LOW]) | |
1788 | rtime = tg->last_low_overflow_time[READ]; | |
1789 | if (tg->bps[WRITE][LIMIT_LOW] || tg->iops[WRITE][LIMIT_LOW]) | |
1790 | wtime = tg->last_low_overflow_time[WRITE]; | |
1791 | return min(rtime, wtime); | |
1792 | } | |
1793 | ||
1794 | /* tg should not be an intermediate node */ | |
1795 | static unsigned long tg_last_low_overflow_time(struct throtl_grp *tg) | |
1796 | { | |
1797 | struct throtl_service_queue *parent_sq; | |
1798 | struct throtl_grp *parent = tg; | |
1799 | unsigned long ret = __tg_last_low_overflow_time(tg); | |
1800 | ||
1801 | while (true) { | |
1802 | parent_sq = parent->service_queue.parent_sq; | |
1803 | parent = sq_to_tg(parent_sq); | |
1804 | if (!parent) | |
1805 | break; | |
1806 | ||
1807 | /* | |
1808 | * The parent doesn't have low limit, it always reaches low | |
1809 | * limit. Its overflow time is useless for children | |
1810 | */ | |
1811 | if (!parent->bps[READ][LIMIT_LOW] && | |
1812 | !parent->iops[READ][LIMIT_LOW] && | |
1813 | !parent->bps[WRITE][LIMIT_LOW] && | |
1814 | !parent->iops[WRITE][LIMIT_LOW]) | |
1815 | continue; | |
1816 | if (time_after(__tg_last_low_overflow_time(parent), ret)) | |
1817 | ret = __tg_last_low_overflow_time(parent); | |
1818 | } | |
1819 | return ret; | |
1820 | } | |
1821 | ||
9e234eea SL |
1822 | static bool throtl_tg_is_idle(struct throtl_grp *tg) |
1823 | { | |
1824 | /* | |
1825 | * cgroup is idle if: | |
1826 | * - single idle is too long, longer than a fixed value (in case user | |
b4f428ef | 1827 | * configure a too big threshold) or 4 times of idletime threshold |
9e234eea | 1828 | * - average think time is more than threshold |
53696b8d | 1829 | * - IO latency is largely below threshold |
9e234eea | 1830 | */ |
b4f428ef | 1831 | unsigned long time; |
4cff729f | 1832 | bool ret; |
9e234eea | 1833 | |
b4f428ef SL |
1834 | time = min_t(unsigned long, MAX_IDLE_TIME, 4 * tg->idletime_threshold); |
1835 | ret = tg->latency_target == DFL_LATENCY_TARGET || | |
1836 | tg->idletime_threshold == DFL_IDLE_THRESHOLD || | |
1837 | (ktime_get_ns() >> 10) - tg->last_finish_time > time || | |
1838 | tg->avg_idletime > tg->idletime_threshold || | |
1839 | (tg->latency_target && tg->bio_cnt && | |
53696b8d | 1840 | tg->bad_bio_cnt * 5 < tg->bio_cnt); |
4cff729f SL |
1841 | throtl_log(&tg->service_queue, |
1842 | "avg_idle=%ld, idle_threshold=%ld, bad_bio=%d, total_bio=%d, is_idle=%d, scale=%d", | |
1843 | tg->avg_idletime, tg->idletime_threshold, tg->bad_bio_cnt, | |
1844 | tg->bio_cnt, ret, tg->td->scale); | |
1845 | return ret; | |
9e234eea SL |
1846 | } |
1847 | ||
c79892c5 SL |
1848 | static bool throtl_tg_can_upgrade(struct throtl_grp *tg) |
1849 | { | |
1850 | struct throtl_service_queue *sq = &tg->service_queue; | |
1851 | bool read_limit, write_limit; | |
1852 | ||
1853 | /* | |
1854 | * if cgroup reaches low limit (if low limit is 0, the cgroup always | |
1855 | * reaches), it's ok to upgrade to next limit | |
1856 | */ | |
1857 | read_limit = tg->bps[READ][LIMIT_LOW] || tg->iops[READ][LIMIT_LOW]; | |
1858 | write_limit = tg->bps[WRITE][LIMIT_LOW] || tg->iops[WRITE][LIMIT_LOW]; | |
1859 | if (!read_limit && !write_limit) | |
1860 | return true; | |
1861 | if (read_limit && sq->nr_queued[READ] && | |
1862 | (!write_limit || sq->nr_queued[WRITE])) | |
1863 | return true; | |
1864 | if (write_limit && sq->nr_queued[WRITE] && | |
1865 | (!read_limit || sq->nr_queued[READ])) | |
1866 | return true; | |
aec24246 SL |
1867 | |
1868 | if (time_after_eq(jiffies, | |
fa6fb5aa SL |
1869 | tg_last_low_overflow_time(tg) + tg->td->throtl_slice) && |
1870 | throtl_tg_is_idle(tg)) | |
aec24246 | 1871 | return true; |
c79892c5 SL |
1872 | return false; |
1873 | } | |
1874 | ||
1875 | static bool throtl_hierarchy_can_upgrade(struct throtl_grp *tg) | |
1876 | { | |
1877 | while (true) { | |
1878 | if (throtl_tg_can_upgrade(tg)) | |
1879 | return true; | |
1880 | tg = sq_to_tg(tg->service_queue.parent_sq); | |
1881 | if (!tg || !tg_to_blkg(tg)->parent) | |
1882 | return false; | |
1883 | } | |
1884 | return false; | |
1885 | } | |
1886 | ||
1887 | static bool throtl_can_upgrade(struct throtl_data *td, | |
1888 | struct throtl_grp *this_tg) | |
1889 | { | |
1890 | struct cgroup_subsys_state *pos_css; | |
1891 | struct blkcg_gq *blkg; | |
1892 | ||
1893 | if (td->limit_index != LIMIT_LOW) | |
1894 | return false; | |
1895 | ||
297e3d85 | 1896 | if (time_before(jiffies, td->low_downgrade_time + td->throtl_slice)) |
3f0abd80 SL |
1897 | return false; |
1898 | ||
c79892c5 SL |
1899 | rcu_read_lock(); |
1900 | blkg_for_each_descendant_post(blkg, pos_css, td->queue->root_blkg) { | |
1901 | struct throtl_grp *tg = blkg_to_tg(blkg); | |
1902 | ||
1903 | if (tg == this_tg) | |
1904 | continue; | |
1905 | if (!list_empty(&tg_to_blkg(tg)->blkcg->css.children)) | |
1906 | continue; | |
1907 | if (!throtl_hierarchy_can_upgrade(tg)) { | |
1908 | rcu_read_unlock(); | |
1909 | return false; | |
1910 | } | |
1911 | } | |
1912 | rcu_read_unlock(); | |
1913 | return true; | |
1914 | } | |
1915 | ||
fa6fb5aa SL |
1916 | static void throtl_upgrade_check(struct throtl_grp *tg) |
1917 | { | |
1918 | unsigned long now = jiffies; | |
1919 | ||
1920 | if (tg->td->limit_index != LIMIT_LOW) | |
1921 | return; | |
1922 | ||
1923 | if (time_after(tg->last_check_time + tg->td->throtl_slice, now)) | |
1924 | return; | |
1925 | ||
1926 | tg->last_check_time = now; | |
1927 | ||
1928 | if (!time_after_eq(now, | |
1929 | __tg_last_low_overflow_time(tg) + tg->td->throtl_slice)) | |
1930 | return; | |
1931 | ||
1932 | if (throtl_can_upgrade(tg->td, NULL)) | |
1933 | throtl_upgrade_state(tg->td); | |
1934 | } | |
1935 | ||
c79892c5 SL |
1936 | static void throtl_upgrade_state(struct throtl_data *td) |
1937 | { | |
1938 | struct cgroup_subsys_state *pos_css; | |
1939 | struct blkcg_gq *blkg; | |
1940 | ||
4cff729f | 1941 | throtl_log(&td->service_queue, "upgrade to max"); |
c79892c5 | 1942 | td->limit_index = LIMIT_MAX; |
3f0abd80 | 1943 | td->low_upgrade_time = jiffies; |
7394e31f | 1944 | td->scale = 0; |
c79892c5 SL |
1945 | rcu_read_lock(); |
1946 | blkg_for_each_descendant_post(blkg, pos_css, td->queue->root_blkg) { | |
1947 | struct throtl_grp *tg = blkg_to_tg(blkg); | |
1948 | struct throtl_service_queue *sq = &tg->service_queue; | |
1949 | ||
1950 | tg->disptime = jiffies - 1; | |
1951 | throtl_select_dispatch(sq); | |
4f02fb76 | 1952 | throtl_schedule_next_dispatch(sq, true); |
c79892c5 SL |
1953 | } |
1954 | rcu_read_unlock(); | |
1955 | throtl_select_dispatch(&td->service_queue); | |
4f02fb76 | 1956 | throtl_schedule_next_dispatch(&td->service_queue, true); |
c79892c5 SL |
1957 | queue_work(kthrotld_workqueue, &td->dispatch_work); |
1958 | } | |
1959 | ||
3f0abd80 SL |
1960 | static void throtl_downgrade_state(struct throtl_data *td, int new) |
1961 | { | |
7394e31f SL |
1962 | td->scale /= 2; |
1963 | ||
4cff729f | 1964 | throtl_log(&td->service_queue, "downgrade, scale %d", td->scale); |
7394e31f SL |
1965 | if (td->scale) { |
1966 | td->low_upgrade_time = jiffies - td->scale * td->throtl_slice; | |
1967 | return; | |
1968 | } | |
1969 | ||
3f0abd80 SL |
1970 | td->limit_index = new; |
1971 | td->low_downgrade_time = jiffies; | |
1972 | } | |
1973 | ||
1974 | static bool throtl_tg_can_downgrade(struct throtl_grp *tg) | |
1975 | { | |
1976 | struct throtl_data *td = tg->td; | |
1977 | unsigned long now = jiffies; | |
1978 | ||
1979 | /* | |
1980 | * If cgroup is below low limit, consider downgrade and throttle other | |
1981 | * cgroups | |
1982 | */ | |
297e3d85 SL |
1983 | if (time_after_eq(now, td->low_upgrade_time + td->throtl_slice) && |
1984 | time_after_eq(now, tg_last_low_overflow_time(tg) + | |
fa6fb5aa SL |
1985 | td->throtl_slice) && |
1986 | (!throtl_tg_is_idle(tg) || | |
1987 | !list_empty(&tg_to_blkg(tg)->blkcg->css.children))) | |
3f0abd80 SL |
1988 | return true; |
1989 | return false; | |
1990 | } | |
1991 | ||
1992 | static bool throtl_hierarchy_can_downgrade(struct throtl_grp *tg) | |
1993 | { | |
1994 | while (true) { | |
1995 | if (!throtl_tg_can_downgrade(tg)) | |
1996 | return false; | |
1997 | tg = sq_to_tg(tg->service_queue.parent_sq); | |
1998 | if (!tg || !tg_to_blkg(tg)->parent) | |
1999 | break; | |
2000 | } | |
2001 | return true; | |
2002 | } | |
2003 | ||
2004 | static void throtl_downgrade_check(struct throtl_grp *tg) | |
2005 | { | |
2006 | uint64_t bps; | |
2007 | unsigned int iops; | |
2008 | unsigned long elapsed_time; | |
2009 | unsigned long now = jiffies; | |
2010 | ||
2011 | if (tg->td->limit_index != LIMIT_MAX || | |
2012 | !tg->td->limit_valid[LIMIT_LOW]) | |
2013 | return; | |
2014 | if (!list_empty(&tg_to_blkg(tg)->blkcg->css.children)) | |
2015 | return; | |
297e3d85 | 2016 | if (time_after(tg->last_check_time + tg->td->throtl_slice, now)) |
3f0abd80 SL |
2017 | return; |
2018 | ||
2019 | elapsed_time = now - tg->last_check_time; | |
2020 | tg->last_check_time = now; | |
2021 | ||
297e3d85 SL |
2022 | if (time_before(now, tg_last_low_overflow_time(tg) + |
2023 | tg->td->throtl_slice)) | |
3f0abd80 SL |
2024 | return; |
2025 | ||
2026 | if (tg->bps[READ][LIMIT_LOW]) { | |
2027 | bps = tg->last_bytes_disp[READ] * HZ; | |
2028 | do_div(bps, elapsed_time); | |
2029 | if (bps >= tg->bps[READ][LIMIT_LOW]) | |
2030 | tg->last_low_overflow_time[READ] = now; | |
2031 | } | |
2032 | ||
2033 | if (tg->bps[WRITE][LIMIT_LOW]) { | |
2034 | bps = tg->last_bytes_disp[WRITE] * HZ; | |
2035 | do_div(bps, elapsed_time); | |
2036 | if (bps >= tg->bps[WRITE][LIMIT_LOW]) | |
2037 | tg->last_low_overflow_time[WRITE] = now; | |
2038 | } | |
2039 | ||
2040 | if (tg->iops[READ][LIMIT_LOW]) { | |
2041 | iops = tg->last_io_disp[READ] * HZ / elapsed_time; | |
2042 | if (iops >= tg->iops[READ][LIMIT_LOW]) | |
2043 | tg->last_low_overflow_time[READ] = now; | |
2044 | } | |
2045 | ||
2046 | if (tg->iops[WRITE][LIMIT_LOW]) { | |
2047 | iops = tg->last_io_disp[WRITE] * HZ / elapsed_time; | |
2048 | if (iops >= tg->iops[WRITE][LIMIT_LOW]) | |
2049 | tg->last_low_overflow_time[WRITE] = now; | |
2050 | } | |
2051 | ||
2052 | /* | |
2053 | * If cgroup is below low limit, consider downgrade and throttle other | |
2054 | * cgroups | |
2055 | */ | |
2056 | if (throtl_hierarchy_can_downgrade(tg)) | |
2057 | throtl_downgrade_state(tg->td, LIMIT_LOW); | |
2058 | ||
2059 | tg->last_bytes_disp[READ] = 0; | |
2060 | tg->last_bytes_disp[WRITE] = 0; | |
2061 | tg->last_io_disp[READ] = 0; | |
2062 | tg->last_io_disp[WRITE] = 0; | |
2063 | } | |
2064 | ||
9e234eea SL |
2065 | static void blk_throtl_update_idletime(struct throtl_grp *tg) |
2066 | { | |
2067 | unsigned long now = ktime_get_ns() >> 10; | |
2068 | unsigned long last_finish_time = tg->last_finish_time; | |
2069 | ||
2070 | if (now <= last_finish_time || last_finish_time == 0 || | |
2071 | last_finish_time == tg->checked_last_finish_time) | |
2072 | return; | |
2073 | ||
2074 | tg->avg_idletime = (tg->avg_idletime * 7 + now - last_finish_time) >> 3; | |
2075 | tg->checked_last_finish_time = last_finish_time; | |
2076 | } | |
2077 | ||
b9147dd1 SL |
2078 | #ifdef CONFIG_BLK_DEV_THROTTLING_LOW |
2079 | static void throtl_update_latency_buckets(struct throtl_data *td) | |
2080 | { | |
b889bf66 JQ |
2081 | struct avg_latency_bucket avg_latency[2][LATENCY_BUCKET_SIZE]; |
2082 | int i, cpu, rw; | |
2083 | unsigned long last_latency[2] = { 0 }; | |
2084 | unsigned long latency[2]; | |
b9147dd1 SL |
2085 | |
2086 | if (!blk_queue_nonrot(td->queue)) | |
2087 | return; | |
2088 | if (time_before(jiffies, td->last_calculate_time + HZ)) | |
2089 | return; | |
2090 | td->last_calculate_time = jiffies; | |
2091 | ||
2092 | memset(avg_latency, 0, sizeof(avg_latency)); | |
b889bf66 JQ |
2093 | for (rw = READ; rw <= WRITE; rw++) { |
2094 | for (i = 0; i < LATENCY_BUCKET_SIZE; i++) { | |
2095 | struct latency_bucket *tmp = &td->tmp_buckets[rw][i]; | |
2096 | ||
2097 | for_each_possible_cpu(cpu) { | |
2098 | struct latency_bucket *bucket; | |
2099 | ||
2100 | /* this isn't race free, but ok in practice */ | |
2101 | bucket = per_cpu_ptr(td->latency_buckets[rw], | |
2102 | cpu); | |
2103 | tmp->total_latency += bucket[i].total_latency; | |
2104 | tmp->samples += bucket[i].samples; | |
2105 | bucket[i].total_latency = 0; | |
2106 | bucket[i].samples = 0; | |
2107 | } | |
b9147dd1 | 2108 | |
b889bf66 JQ |
2109 | if (tmp->samples >= 32) { |
2110 | int samples = tmp->samples; | |
b9147dd1 | 2111 | |
b889bf66 | 2112 | latency[rw] = tmp->total_latency; |
b9147dd1 | 2113 | |
b889bf66 JQ |
2114 | tmp->total_latency = 0; |
2115 | tmp->samples = 0; | |
2116 | latency[rw] /= samples; | |
2117 | if (latency[rw] == 0) | |
2118 | continue; | |
2119 | avg_latency[rw][i].latency = latency[rw]; | |
2120 | } | |
b9147dd1 SL |
2121 | } |
2122 | } | |
2123 | ||
b889bf66 JQ |
2124 | for (rw = READ; rw <= WRITE; rw++) { |
2125 | for (i = 0; i < LATENCY_BUCKET_SIZE; i++) { | |
2126 | if (!avg_latency[rw][i].latency) { | |
2127 | if (td->avg_buckets[rw][i].latency < last_latency[rw]) | |
2128 | td->avg_buckets[rw][i].latency = | |
2129 | last_latency[rw]; | |
2130 | continue; | |
2131 | } | |
b9147dd1 | 2132 | |
b889bf66 JQ |
2133 | if (!td->avg_buckets[rw][i].valid) |
2134 | latency[rw] = avg_latency[rw][i].latency; | |
2135 | else | |
2136 | latency[rw] = (td->avg_buckets[rw][i].latency * 7 + | |
2137 | avg_latency[rw][i].latency) >> 3; | |
b9147dd1 | 2138 | |
b889bf66 JQ |
2139 | td->avg_buckets[rw][i].latency = max(latency[rw], |
2140 | last_latency[rw]); | |
2141 | td->avg_buckets[rw][i].valid = true; | |
2142 | last_latency[rw] = td->avg_buckets[rw][i].latency; | |
2143 | } | |
b9147dd1 | 2144 | } |
4cff729f SL |
2145 | |
2146 | for (i = 0; i < LATENCY_BUCKET_SIZE; i++) | |
2147 | throtl_log(&td->service_queue, | |
b889bf66 JQ |
2148 | "Latency bucket %d: read latency=%ld, read valid=%d, " |
2149 | "write latency=%ld, write valid=%d", i, | |
2150 | td->avg_buckets[READ][i].latency, | |
2151 | td->avg_buckets[READ][i].valid, | |
2152 | td->avg_buckets[WRITE][i].latency, | |
2153 | td->avg_buckets[WRITE][i].valid); | |
b9147dd1 SL |
2154 | } |
2155 | #else | |
2156 | static inline void throtl_update_latency_buckets(struct throtl_data *td) | |
2157 | { | |
2158 | } | |
2159 | #endif | |
2160 | ||
ae118896 TH |
2161 | bool blk_throtl_bio(struct request_queue *q, struct blkcg_gq *blkg, |
2162 | struct bio *bio) | |
e43473b7 | 2163 | { |
c5cc2070 | 2164 | struct throtl_qnode *qn = NULL; |
b5f2954d | 2165 | struct throtl_grp *tg = blkg_to_tg(blkg ?: q->root_blkg); |
73f0d49a | 2166 | struct throtl_service_queue *sq; |
0e9f4164 | 2167 | bool rw = bio_data_dir(bio); |
bc16a4f9 | 2168 | bool throttled = false; |
b9147dd1 | 2169 | struct throtl_data *td = tg->td; |
e43473b7 | 2170 | |
ae118896 TH |
2171 | WARN_ON_ONCE(!rcu_read_lock_held()); |
2172 | ||
2a0f61e6 | 2173 | /* see throtl_charge_bio() */ |
7ca46438 TH |
2174 | if (bio_flagged(bio, BIO_THROTTLED)) |
2175 | goto out; | |
2176 | ||
2177 | if (!cgroup_subsys_on_dfl(io_cgrp_subsys)) { | |
2178 | blkg_rwstat_add(&tg->stat_bytes, bio->bi_opf, | |
2179 | bio->bi_iter.bi_size); | |
2180 | blkg_rwstat_add(&tg->stat_ios, bio->bi_opf, 1); | |
2181 | } | |
2182 | ||
2183 | if (!tg->has_rules[rw]) | |
bc16a4f9 | 2184 | goto out; |
e43473b7 | 2185 | |
0d945c1f | 2186 | spin_lock_irq(&q->queue_lock); |
c9589f03 | 2187 | |
b9147dd1 SL |
2188 | throtl_update_latency_buckets(td); |
2189 | ||
9e234eea SL |
2190 | blk_throtl_update_idletime(tg); |
2191 | ||
73f0d49a TH |
2192 | sq = &tg->service_queue; |
2193 | ||
c79892c5 | 2194 | again: |
9e660acf | 2195 | while (true) { |
3f0abd80 SL |
2196 | if (tg->last_low_overflow_time[rw] == 0) |
2197 | tg->last_low_overflow_time[rw] = jiffies; | |
2198 | throtl_downgrade_check(tg); | |
fa6fb5aa | 2199 | throtl_upgrade_check(tg); |
9e660acf TH |
2200 | /* throtl is FIFO - if bios are already queued, should queue */ |
2201 | if (sq->nr_queued[rw]) | |
2202 | break; | |
de701c74 | 2203 | |
9e660acf | 2204 | /* if above limits, break to queue */ |
c79892c5 | 2205 | if (!tg_may_dispatch(tg, bio, NULL)) { |
3f0abd80 | 2206 | tg->last_low_overflow_time[rw] = jiffies; |
b9147dd1 SL |
2207 | if (throtl_can_upgrade(td, tg)) { |
2208 | throtl_upgrade_state(td); | |
c79892c5 SL |
2209 | goto again; |
2210 | } | |
9e660acf | 2211 | break; |
c79892c5 | 2212 | } |
9e660acf TH |
2213 | |
2214 | /* within limits, let's charge and dispatch directly */ | |
e43473b7 | 2215 | throtl_charge_bio(tg, bio); |
04521db0 VG |
2216 | |
2217 | /* | |
2218 | * We need to trim slice even when bios are not being queued | |
2219 | * otherwise it might happen that a bio is not queued for | |
2220 | * a long time and slice keeps on extending and trim is not | |
2221 | * called for a long time. Now if limits are reduced suddenly | |
2222 | * we take into account all the IO dispatched so far at new | |
2223 | * low rate and * newly queued IO gets a really long dispatch | |
2224 | * time. | |
2225 | * | |
2226 | * So keep on trimming slice even if bio is not queued. | |
2227 | */ | |
0f3457f6 | 2228 | throtl_trim_slice(tg, rw); |
9e660acf TH |
2229 | |
2230 | /* | |
2231 | * @bio passed through this layer without being throttled. | |
2232 | * Climb up the ladder. If we''re already at the top, it | |
2233 | * can be executed directly. | |
2234 | */ | |
c5cc2070 | 2235 | qn = &tg->qnode_on_parent[rw]; |
9e660acf TH |
2236 | sq = sq->parent_sq; |
2237 | tg = sq_to_tg(sq); | |
2238 | if (!tg) | |
2239 | goto out_unlock; | |
e43473b7 VG |
2240 | } |
2241 | ||
9e660acf | 2242 | /* out-of-limit, queue to @tg */ |
fda6f272 TH |
2243 | throtl_log(sq, "[%c] bio. bdisp=%llu sz=%u bps=%llu iodisp=%u iops=%u queued=%d/%d", |
2244 | rw == READ ? 'R' : 'W', | |
9f626e37 SL |
2245 | tg->bytes_disp[rw], bio->bi_iter.bi_size, |
2246 | tg_bps_limit(tg, rw), | |
2247 | tg->io_disp[rw], tg_iops_limit(tg, rw), | |
fda6f272 | 2248 | sq->nr_queued[READ], sq->nr_queued[WRITE]); |
e43473b7 | 2249 | |
3f0abd80 SL |
2250 | tg->last_low_overflow_time[rw] = jiffies; |
2251 | ||
b9147dd1 | 2252 | td->nr_queued[rw]++; |
c5cc2070 | 2253 | throtl_add_bio_tg(bio, qn, tg); |
bc16a4f9 | 2254 | throttled = true; |
e43473b7 | 2255 | |
7f52f98c TH |
2256 | /* |
2257 | * Update @tg's dispatch time and force schedule dispatch if @tg | |
2258 | * was empty before @bio. The forced scheduling isn't likely to | |
2259 | * cause undue delay as @bio is likely to be dispatched directly if | |
2260 | * its @tg's disptime is not in the future. | |
2261 | */ | |
0e9f4164 | 2262 | if (tg->flags & THROTL_TG_WAS_EMPTY) { |
77216b04 | 2263 | tg_update_disptime(tg); |
7f52f98c | 2264 | throtl_schedule_next_dispatch(tg->service_queue.parent_sq, true); |
e43473b7 VG |
2265 | } |
2266 | ||
bc16a4f9 | 2267 | out_unlock: |
0d945c1f | 2268 | spin_unlock_irq(&q->queue_lock); |
bc16a4f9 | 2269 | out: |
111be883 | 2270 | bio_set_flag(bio, BIO_THROTTLED); |
b9147dd1 SL |
2271 | |
2272 | #ifdef CONFIG_BLK_DEV_THROTTLING_LOW | |
2273 | if (throttled || !td->track_bio_latency) | |
5238dcf4 | 2274 | bio->bi_issue.value |= BIO_ISSUE_THROTL_SKIP_LATENCY; |
b9147dd1 | 2275 | #endif |
bc16a4f9 | 2276 | return throttled; |
e43473b7 VG |
2277 | } |
2278 | ||
9e234eea | 2279 | #ifdef CONFIG_BLK_DEV_THROTTLING_LOW |
b9147dd1 SL |
2280 | static void throtl_track_latency(struct throtl_data *td, sector_t size, |
2281 | int op, unsigned long time) | |
2282 | { | |
2283 | struct latency_bucket *latency; | |
2284 | int index; | |
2285 | ||
b889bf66 JQ |
2286 | if (!td || td->limit_index != LIMIT_LOW || |
2287 | !(op == REQ_OP_READ || op == REQ_OP_WRITE) || | |
b9147dd1 SL |
2288 | !blk_queue_nonrot(td->queue)) |
2289 | return; | |
2290 | ||
2291 | index = request_bucket_index(size); | |
2292 | ||
b889bf66 | 2293 | latency = get_cpu_ptr(td->latency_buckets[op]); |
b9147dd1 SL |
2294 | latency[index].total_latency += time; |
2295 | latency[index].samples++; | |
b889bf66 | 2296 | put_cpu_ptr(td->latency_buckets[op]); |
b9147dd1 SL |
2297 | } |
2298 | ||
2299 | void blk_throtl_stat_add(struct request *rq, u64 time_ns) | |
2300 | { | |
2301 | struct request_queue *q = rq->q; | |
2302 | struct throtl_data *td = q->td; | |
2303 | ||
3d244306 HT |
2304 | throtl_track_latency(td, blk_rq_stats_sectors(rq), req_op(rq), |
2305 | time_ns >> 10); | |
b9147dd1 SL |
2306 | } |
2307 | ||
9e234eea SL |
2308 | void blk_throtl_bio_endio(struct bio *bio) |
2309 | { | |
08e18eab | 2310 | struct blkcg_gq *blkg; |
9e234eea | 2311 | struct throtl_grp *tg; |
b9147dd1 SL |
2312 | u64 finish_time_ns; |
2313 | unsigned long finish_time; | |
2314 | unsigned long start_time; | |
2315 | unsigned long lat; | |
b889bf66 | 2316 | int rw = bio_data_dir(bio); |
9e234eea | 2317 | |
08e18eab JB |
2318 | blkg = bio->bi_blkg; |
2319 | if (!blkg) | |
9e234eea | 2320 | return; |
08e18eab | 2321 | tg = blkg_to_tg(blkg); |
9e234eea | 2322 | |
b9147dd1 SL |
2323 | finish_time_ns = ktime_get_ns(); |
2324 | tg->last_finish_time = finish_time_ns >> 10; | |
2325 | ||
5238dcf4 OS |
2326 | start_time = bio_issue_time(&bio->bi_issue) >> 10; |
2327 | finish_time = __bio_issue_time(finish_time_ns) >> 10; | |
08e18eab | 2328 | if (!start_time || finish_time <= start_time) |
53696b8d SL |
2329 | return; |
2330 | ||
2331 | lat = finish_time - start_time; | |
b9147dd1 | 2332 | /* this is only for bio based driver */ |
5238dcf4 OS |
2333 | if (!(bio->bi_issue.value & BIO_ISSUE_THROTL_SKIP_LATENCY)) |
2334 | throtl_track_latency(tg->td, bio_issue_size(&bio->bi_issue), | |
2335 | bio_op(bio), lat); | |
53696b8d | 2336 | |
6679a90c | 2337 | if (tg->latency_target && lat >= tg->td->filtered_latency) { |
53696b8d SL |
2338 | int bucket; |
2339 | unsigned int threshold; | |
2340 | ||
5238dcf4 | 2341 | bucket = request_bucket_index(bio_issue_size(&bio->bi_issue)); |
b889bf66 | 2342 | threshold = tg->td->avg_buckets[rw][bucket].latency + |
53696b8d SL |
2343 | tg->latency_target; |
2344 | if (lat > threshold) | |
2345 | tg->bad_bio_cnt++; | |
2346 | /* | |
2347 | * Not race free, could get wrong count, which means cgroups | |
2348 | * will be throttled | |
2349 | */ | |
2350 | tg->bio_cnt++; | |
2351 | } | |
2352 | ||
2353 | if (time_after(jiffies, tg->bio_cnt_reset_time) || tg->bio_cnt > 1024) { | |
2354 | tg->bio_cnt_reset_time = tg->td->throtl_slice + jiffies; | |
2355 | tg->bio_cnt /= 2; | |
2356 | tg->bad_bio_cnt /= 2; | |
b9147dd1 | 2357 | } |
9e234eea SL |
2358 | } |
2359 | #endif | |
2360 | ||
2a12f0dc TH |
2361 | /* |
2362 | * Dispatch all bios from all children tg's queued on @parent_sq. On | |
2363 | * return, @parent_sq is guaranteed to not have any active children tg's | |
2364 | * and all bios from previously active tg's are on @parent_sq->bio_lists[]. | |
2365 | */ | |
2366 | static void tg_drain_bios(struct throtl_service_queue *parent_sq) | |
2367 | { | |
2368 | struct throtl_grp *tg; | |
2369 | ||
2370 | while ((tg = throtl_rb_first(parent_sq))) { | |
2371 | struct throtl_service_queue *sq = &tg->service_queue; | |
2372 | struct bio *bio; | |
2373 | ||
2374 | throtl_dequeue_tg(tg); | |
2375 | ||
c5cc2070 | 2376 | while ((bio = throtl_peek_queued(&sq->queued[READ]))) |
2a12f0dc | 2377 | tg_dispatch_one_bio(tg, bio_data_dir(bio)); |
c5cc2070 | 2378 | while ((bio = throtl_peek_queued(&sq->queued[WRITE]))) |
2a12f0dc TH |
2379 | tg_dispatch_one_bio(tg, bio_data_dir(bio)); |
2380 | } | |
2381 | } | |
2382 | ||
c9a929dd TH |
2383 | /** |
2384 | * blk_throtl_drain - drain throttled bios | |
2385 | * @q: request_queue to drain throttled bios for | |
2386 | * | |
2387 | * Dispatch all currently throttled bios on @q through ->make_request_fn(). | |
2388 | */ | |
2389 | void blk_throtl_drain(struct request_queue *q) | |
0d945c1f | 2390 | __releases(&q->queue_lock) __acquires(&q->queue_lock) |
c9a929dd TH |
2391 | { |
2392 | struct throtl_data *td = q->td; | |
2a12f0dc | 2393 | struct blkcg_gq *blkg; |
492eb21b | 2394 | struct cgroup_subsys_state *pos_css; |
c9a929dd | 2395 | struct bio *bio; |
651930bc | 2396 | int rw; |
c9a929dd | 2397 | |
2a12f0dc | 2398 | rcu_read_lock(); |
c9a929dd | 2399 | |
2a12f0dc TH |
2400 | /* |
2401 | * Drain each tg while doing post-order walk on the blkg tree, so | |
2402 | * that all bios are propagated to td->service_queue. It'd be | |
2403 | * better to walk service_queue tree directly but blkg walk is | |
2404 | * easier. | |
2405 | */ | |
492eb21b | 2406 | blkg_for_each_descendant_post(blkg, pos_css, td->queue->root_blkg) |
2a12f0dc | 2407 | tg_drain_bios(&blkg_to_tg(blkg)->service_queue); |
73f0d49a | 2408 | |
2a12f0dc TH |
2409 | /* finally, transfer bios from top-level tg's into the td */ |
2410 | tg_drain_bios(&td->service_queue); | |
2411 | ||
2412 | rcu_read_unlock(); | |
0d945c1f | 2413 | spin_unlock_irq(&q->queue_lock); |
c9a929dd | 2414 | |
2a12f0dc | 2415 | /* all bios now should be in td->service_queue, issue them */ |
651930bc | 2416 | for (rw = READ; rw <= WRITE; rw++) |
c5cc2070 TH |
2417 | while ((bio = throtl_pop_queued(&td->service_queue.queued[rw], |
2418 | NULL))) | |
651930bc | 2419 | generic_make_request(bio); |
c9a929dd | 2420 | |
0d945c1f | 2421 | spin_lock_irq(&q->queue_lock); |
c9a929dd TH |
2422 | } |
2423 | ||
e43473b7 VG |
2424 | int blk_throtl_init(struct request_queue *q) |
2425 | { | |
2426 | struct throtl_data *td; | |
a2b1693b | 2427 | int ret; |
e43473b7 VG |
2428 | |
2429 | td = kzalloc_node(sizeof(*td), GFP_KERNEL, q->node); | |
2430 | if (!td) | |
2431 | return -ENOMEM; | |
b889bf66 | 2432 | td->latency_buckets[READ] = __alloc_percpu(sizeof(struct latency_bucket) * |
b9147dd1 | 2433 | LATENCY_BUCKET_SIZE, __alignof__(u64)); |
b889bf66 JQ |
2434 | if (!td->latency_buckets[READ]) { |
2435 | kfree(td); | |
2436 | return -ENOMEM; | |
2437 | } | |
2438 | td->latency_buckets[WRITE] = __alloc_percpu(sizeof(struct latency_bucket) * | |
b9147dd1 | 2439 | LATENCY_BUCKET_SIZE, __alignof__(u64)); |
b889bf66 JQ |
2440 | if (!td->latency_buckets[WRITE]) { |
2441 | free_percpu(td->latency_buckets[READ]); | |
b9147dd1 SL |
2442 | kfree(td); |
2443 | return -ENOMEM; | |
2444 | } | |
e43473b7 | 2445 | |
69df0ab0 | 2446 | INIT_WORK(&td->dispatch_work, blk_throtl_dispatch_work_fn); |
b2ce2643 | 2447 | throtl_service_queue_init(&td->service_queue); |
e43473b7 | 2448 | |
cd1604fa | 2449 | q->td = td; |
29b12589 | 2450 | td->queue = q; |
02977e4a | 2451 | |
9f626e37 | 2452 | td->limit_valid[LIMIT_MAX] = true; |
cd5ab1b0 | 2453 | td->limit_index = LIMIT_MAX; |
3f0abd80 SL |
2454 | td->low_upgrade_time = jiffies; |
2455 | td->low_downgrade_time = jiffies; | |
9e234eea | 2456 | |
a2b1693b | 2457 | /* activate policy */ |
3c798398 | 2458 | ret = blkcg_activate_policy(q, &blkcg_policy_throtl); |
b9147dd1 | 2459 | if (ret) { |
b889bf66 JQ |
2460 | free_percpu(td->latency_buckets[READ]); |
2461 | free_percpu(td->latency_buckets[WRITE]); | |
f51b802c | 2462 | kfree(td); |
b9147dd1 | 2463 | } |
a2b1693b | 2464 | return ret; |
e43473b7 VG |
2465 | } |
2466 | ||
2467 | void blk_throtl_exit(struct request_queue *q) | |
2468 | { | |
c875f4d0 | 2469 | BUG_ON(!q->td); |
da527770 | 2470 | throtl_shutdown_wq(q); |
3c798398 | 2471 | blkcg_deactivate_policy(q, &blkcg_policy_throtl); |
b889bf66 JQ |
2472 | free_percpu(q->td->latency_buckets[READ]); |
2473 | free_percpu(q->td->latency_buckets[WRITE]); | |
c9a929dd | 2474 | kfree(q->td); |
e43473b7 VG |
2475 | } |
2476 | ||
d61fcfa4 SL |
2477 | void blk_throtl_register_queue(struct request_queue *q) |
2478 | { | |
2479 | struct throtl_data *td; | |
6679a90c | 2480 | int i; |
d61fcfa4 SL |
2481 | |
2482 | td = q->td; | |
2483 | BUG_ON(!td); | |
2484 | ||
6679a90c | 2485 | if (blk_queue_nonrot(q)) { |
d61fcfa4 | 2486 | td->throtl_slice = DFL_THROTL_SLICE_SSD; |
6679a90c SL |
2487 | td->filtered_latency = LATENCY_FILTERED_SSD; |
2488 | } else { | |
d61fcfa4 | 2489 | td->throtl_slice = DFL_THROTL_SLICE_HD; |
6679a90c | 2490 | td->filtered_latency = LATENCY_FILTERED_HD; |
b889bf66 JQ |
2491 | for (i = 0; i < LATENCY_BUCKET_SIZE; i++) { |
2492 | td->avg_buckets[READ][i].latency = DFL_HD_BASELINE_LATENCY; | |
2493 | td->avg_buckets[WRITE][i].latency = DFL_HD_BASELINE_LATENCY; | |
2494 | } | |
6679a90c | 2495 | } |
d61fcfa4 SL |
2496 | #ifndef CONFIG_BLK_DEV_THROTTLING_LOW |
2497 | /* if no low limit, use previous default */ | |
2498 | td->throtl_slice = DFL_THROTL_SLICE_HD; | |
2499 | #endif | |
9e234eea | 2500 | |
344e9ffc | 2501 | td->track_bio_latency = !queue_is_mq(q); |
b9147dd1 SL |
2502 | if (!td->track_bio_latency) |
2503 | blk_stat_enable_accounting(q); | |
d61fcfa4 SL |
2504 | } |
2505 | ||
297e3d85 SL |
2506 | #ifdef CONFIG_BLK_DEV_THROTTLING_LOW |
2507 | ssize_t blk_throtl_sample_time_show(struct request_queue *q, char *page) | |
2508 | { | |
2509 | if (!q->td) | |
2510 | return -EINVAL; | |
2511 | return sprintf(page, "%u\n", jiffies_to_msecs(q->td->throtl_slice)); | |
2512 | } | |
2513 | ||
2514 | ssize_t blk_throtl_sample_time_store(struct request_queue *q, | |
2515 | const char *page, size_t count) | |
2516 | { | |
2517 | unsigned long v; | |
2518 | unsigned long t; | |
2519 | ||
2520 | if (!q->td) | |
2521 | return -EINVAL; | |
2522 | if (kstrtoul(page, 10, &v)) | |
2523 | return -EINVAL; | |
2524 | t = msecs_to_jiffies(v); | |
2525 | if (t == 0 || t > MAX_THROTL_SLICE) | |
2526 | return -EINVAL; | |
2527 | q->td->throtl_slice = t; | |
2528 | return count; | |
2529 | } | |
2530 | #endif | |
2531 | ||
e43473b7 VG |
2532 | static int __init throtl_init(void) |
2533 | { | |
450adcbe VG |
2534 | kthrotld_workqueue = alloc_workqueue("kthrotld", WQ_MEM_RECLAIM, 0); |
2535 | if (!kthrotld_workqueue) | |
2536 | panic("Failed to create kthrotld\n"); | |
2537 | ||
3c798398 | 2538 | return blkcg_policy_register(&blkcg_policy_throtl); |
e43473b7 VG |
2539 | } |
2540 | ||
2541 | module_init(throtl_init); |