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Commit | Line | Data |
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e43473b7 VG |
1 | /* |
2 | * Interface for controlling IO bandwidth on a request queue | |
3 | * | |
4 | * Copyright (C) 2010 Vivek Goyal <vgoyal@redhat.com> | |
5 | */ | |
6 | ||
7 | #include <linux/module.h> | |
8 | #include <linux/slab.h> | |
9 | #include <linux/blkdev.h> | |
10 | #include <linux/bio.h> | |
11 | #include <linux/blktrace_api.h> | |
eea8f41c | 12 | #include <linux/blk-cgroup.h> |
bc9fcbf9 | 13 | #include "blk.h" |
e43473b7 VG |
14 | |
15 | /* Max dispatch from a group in 1 round */ | |
16 | static int throtl_grp_quantum = 8; | |
17 | ||
18 | /* Total max dispatch from all groups in one round */ | |
19 | static int throtl_quantum = 32; | |
20 | ||
d61fcfa4 SL |
21 | /* Throttling is performed over a slice and after that slice is renewed */ |
22 | #define DFL_THROTL_SLICE_HD (HZ / 10) | |
23 | #define DFL_THROTL_SLICE_SSD (HZ / 50) | |
297e3d85 | 24 | #define MAX_THROTL_SLICE (HZ) |
9e234eea SL |
25 | #define DFL_IDLE_THRESHOLD_SSD (1000L) /* 1 ms */ |
26 | #define DFL_IDLE_THRESHOLD_HD (100L * 1000) /* 100 ms */ | |
27 | #define MAX_IDLE_TIME (5L * 1000 * 1000) /* 5 s */ | |
ec80991d SL |
28 | /* default latency target is 0, eg, guarantee IO latency by default */ |
29 | #define DFL_LATENCY_TARGET (0) | |
e43473b7 | 30 | |
b9147dd1 SL |
31 | #define SKIP_LATENCY (((u64)1) << BLK_STAT_RES_SHIFT) |
32 | ||
3c798398 | 33 | static struct blkcg_policy blkcg_policy_throtl; |
0381411e | 34 | |
450adcbe VG |
35 | /* A workqueue to queue throttle related work */ |
36 | static struct workqueue_struct *kthrotld_workqueue; | |
450adcbe | 37 | |
c5cc2070 TH |
38 | /* |
39 | * To implement hierarchical throttling, throtl_grps form a tree and bios | |
40 | * are dispatched upwards level by level until they reach the top and get | |
41 | * issued. When dispatching bios from the children and local group at each | |
42 | * level, if the bios are dispatched into a single bio_list, there's a risk | |
43 | * of a local or child group which can queue many bios at once filling up | |
44 | * the list starving others. | |
45 | * | |
46 | * To avoid such starvation, dispatched bios are queued separately | |
47 | * according to where they came from. When they are again dispatched to | |
48 | * the parent, they're popped in round-robin order so that no single source | |
49 | * hogs the dispatch window. | |
50 | * | |
51 | * throtl_qnode is used to keep the queued bios separated by their sources. | |
52 | * Bios are queued to throtl_qnode which in turn is queued to | |
53 | * throtl_service_queue and then dispatched in round-robin order. | |
54 | * | |
55 | * It's also used to track the reference counts on blkg's. A qnode always | |
56 | * belongs to a throtl_grp and gets queued on itself or the parent, so | |
57 | * incrementing the reference of the associated throtl_grp when a qnode is | |
58 | * queued and decrementing when dequeued is enough to keep the whole blkg | |
59 | * tree pinned while bios are in flight. | |
60 | */ | |
61 | struct throtl_qnode { | |
62 | struct list_head node; /* service_queue->queued[] */ | |
63 | struct bio_list bios; /* queued bios */ | |
64 | struct throtl_grp *tg; /* tg this qnode belongs to */ | |
65 | }; | |
66 | ||
c9e0332e | 67 | struct throtl_service_queue { |
77216b04 TH |
68 | struct throtl_service_queue *parent_sq; /* the parent service_queue */ |
69 | ||
73f0d49a TH |
70 | /* |
71 | * Bios queued directly to this service_queue or dispatched from | |
72 | * children throtl_grp's. | |
73 | */ | |
c5cc2070 | 74 | struct list_head queued[2]; /* throtl_qnode [READ/WRITE] */ |
73f0d49a TH |
75 | unsigned int nr_queued[2]; /* number of queued bios */ |
76 | ||
77 | /* | |
78 | * RB tree of active children throtl_grp's, which are sorted by | |
79 | * their ->disptime. | |
80 | */ | |
c9e0332e TH |
81 | struct rb_root pending_tree; /* RB tree of active tgs */ |
82 | struct rb_node *first_pending; /* first node in the tree */ | |
83 | unsigned int nr_pending; /* # queued in the tree */ | |
84 | unsigned long first_pending_disptime; /* disptime of the first tg */ | |
69df0ab0 | 85 | struct timer_list pending_timer; /* fires on first_pending_disptime */ |
e43473b7 VG |
86 | }; |
87 | ||
5b2c16aa TH |
88 | enum tg_state_flags { |
89 | THROTL_TG_PENDING = 1 << 0, /* on parent's pending tree */ | |
0e9f4164 | 90 | THROTL_TG_WAS_EMPTY = 1 << 1, /* bio_lists[] became non-empty */ |
5b2c16aa TH |
91 | }; |
92 | ||
e43473b7 VG |
93 | #define rb_entry_tg(node) rb_entry((node), struct throtl_grp, rb_node) |
94 | ||
9f626e37 | 95 | enum { |
cd5ab1b0 | 96 | LIMIT_LOW, |
9f626e37 SL |
97 | LIMIT_MAX, |
98 | LIMIT_CNT, | |
99 | }; | |
100 | ||
e43473b7 | 101 | struct throtl_grp { |
f95a04af TH |
102 | /* must be the first member */ |
103 | struct blkg_policy_data pd; | |
104 | ||
c9e0332e | 105 | /* active throtl group service_queue member */ |
e43473b7 VG |
106 | struct rb_node rb_node; |
107 | ||
0f3457f6 TH |
108 | /* throtl_data this group belongs to */ |
109 | struct throtl_data *td; | |
110 | ||
49a2f1e3 TH |
111 | /* this group's service queue */ |
112 | struct throtl_service_queue service_queue; | |
113 | ||
c5cc2070 TH |
114 | /* |
115 | * qnode_on_self is used when bios are directly queued to this | |
116 | * throtl_grp so that local bios compete fairly with bios | |
117 | * dispatched from children. qnode_on_parent is used when bios are | |
118 | * dispatched from this throtl_grp into its parent and will compete | |
119 | * with the sibling qnode_on_parents and the parent's | |
120 | * qnode_on_self. | |
121 | */ | |
122 | struct throtl_qnode qnode_on_self[2]; | |
123 | struct throtl_qnode qnode_on_parent[2]; | |
124 | ||
e43473b7 VG |
125 | /* |
126 | * Dispatch time in jiffies. This is the estimated time when group | |
127 | * will unthrottle and is ready to dispatch more bio. It is used as | |
128 | * key to sort active groups in service tree. | |
129 | */ | |
130 | unsigned long disptime; | |
131 | ||
e43473b7 VG |
132 | unsigned int flags; |
133 | ||
693e751e TH |
134 | /* are there any throtl rules between this group and td? */ |
135 | bool has_rules[2]; | |
136 | ||
cd5ab1b0 | 137 | /* internally used bytes per second rate limits */ |
9f626e37 | 138 | uint64_t bps[2][LIMIT_CNT]; |
cd5ab1b0 SL |
139 | /* user configured bps limits */ |
140 | uint64_t bps_conf[2][LIMIT_CNT]; | |
e43473b7 | 141 | |
cd5ab1b0 | 142 | /* internally used IOPS limits */ |
9f626e37 | 143 | unsigned int iops[2][LIMIT_CNT]; |
cd5ab1b0 SL |
144 | /* user configured IOPS limits */ |
145 | unsigned int iops_conf[2][LIMIT_CNT]; | |
8e89d13f | 146 | |
e43473b7 VG |
147 | /* Number of bytes disptached in current slice */ |
148 | uint64_t bytes_disp[2]; | |
8e89d13f VG |
149 | /* Number of bio's dispatched in current slice */ |
150 | unsigned int io_disp[2]; | |
e43473b7 | 151 | |
3f0abd80 SL |
152 | unsigned long last_low_overflow_time[2]; |
153 | ||
154 | uint64_t last_bytes_disp[2]; | |
155 | unsigned int last_io_disp[2]; | |
156 | ||
157 | unsigned long last_check_time; | |
158 | ||
ec80991d | 159 | unsigned long latency_target; /* us */ |
e43473b7 VG |
160 | /* When did we start a new slice */ |
161 | unsigned long slice_start[2]; | |
162 | unsigned long slice_end[2]; | |
9e234eea SL |
163 | |
164 | unsigned long last_finish_time; /* ns / 1024 */ | |
165 | unsigned long checked_last_finish_time; /* ns / 1024 */ | |
166 | unsigned long avg_idletime; /* ns / 1024 */ | |
167 | unsigned long idletime_threshold; /* us */ | |
e43473b7 VG |
168 | }; |
169 | ||
b9147dd1 SL |
170 | /* We measure latency for request size from <= 4k to >= 1M */ |
171 | #define LATENCY_BUCKET_SIZE 9 | |
172 | ||
173 | struct latency_bucket { | |
174 | unsigned long total_latency; /* ns / 1024 */ | |
175 | int samples; | |
176 | }; | |
177 | ||
178 | struct avg_latency_bucket { | |
179 | unsigned long latency; /* ns / 1024 */ | |
180 | bool valid; | |
181 | }; | |
182 | ||
e43473b7 VG |
183 | struct throtl_data |
184 | { | |
e43473b7 | 185 | /* service tree for active throtl groups */ |
c9e0332e | 186 | struct throtl_service_queue service_queue; |
e43473b7 | 187 | |
e43473b7 VG |
188 | struct request_queue *queue; |
189 | ||
190 | /* Total Number of queued bios on READ and WRITE lists */ | |
191 | unsigned int nr_queued[2]; | |
192 | ||
297e3d85 SL |
193 | unsigned int throtl_slice; |
194 | ||
e43473b7 | 195 | /* Work for dispatching throttled bios */ |
69df0ab0 | 196 | struct work_struct dispatch_work; |
9f626e37 SL |
197 | unsigned int limit_index; |
198 | bool limit_valid[LIMIT_CNT]; | |
3f0abd80 | 199 | |
ada75b6e SL |
200 | unsigned long dft_idletime_threshold; /* us */ |
201 | ||
3f0abd80 SL |
202 | unsigned long low_upgrade_time; |
203 | unsigned long low_downgrade_time; | |
7394e31f SL |
204 | |
205 | unsigned int scale; | |
b9147dd1 SL |
206 | |
207 | struct latency_bucket tmp_buckets[LATENCY_BUCKET_SIZE]; | |
208 | struct avg_latency_bucket avg_buckets[LATENCY_BUCKET_SIZE]; | |
209 | struct latency_bucket __percpu *latency_buckets; | |
210 | unsigned long last_calculate_time; | |
211 | ||
212 | bool track_bio_latency; | |
e43473b7 VG |
213 | }; |
214 | ||
69df0ab0 TH |
215 | static void throtl_pending_timer_fn(unsigned long arg); |
216 | ||
f95a04af TH |
217 | static inline struct throtl_grp *pd_to_tg(struct blkg_policy_data *pd) |
218 | { | |
219 | return pd ? container_of(pd, struct throtl_grp, pd) : NULL; | |
220 | } | |
221 | ||
3c798398 | 222 | static inline struct throtl_grp *blkg_to_tg(struct blkcg_gq *blkg) |
0381411e | 223 | { |
f95a04af | 224 | return pd_to_tg(blkg_to_pd(blkg, &blkcg_policy_throtl)); |
0381411e TH |
225 | } |
226 | ||
3c798398 | 227 | static inline struct blkcg_gq *tg_to_blkg(struct throtl_grp *tg) |
0381411e | 228 | { |
f95a04af | 229 | return pd_to_blkg(&tg->pd); |
0381411e TH |
230 | } |
231 | ||
fda6f272 TH |
232 | /** |
233 | * sq_to_tg - return the throl_grp the specified service queue belongs to | |
234 | * @sq: the throtl_service_queue of interest | |
235 | * | |
236 | * Return the throtl_grp @sq belongs to. If @sq is the top-level one | |
237 | * embedded in throtl_data, %NULL is returned. | |
238 | */ | |
239 | static struct throtl_grp *sq_to_tg(struct throtl_service_queue *sq) | |
240 | { | |
241 | if (sq && sq->parent_sq) | |
242 | return container_of(sq, struct throtl_grp, service_queue); | |
243 | else | |
244 | return NULL; | |
245 | } | |
246 | ||
247 | /** | |
248 | * sq_to_td - return throtl_data the specified service queue belongs to | |
249 | * @sq: the throtl_service_queue of interest | |
250 | * | |
b43daedc | 251 | * A service_queue can be embedded in either a throtl_grp or throtl_data. |
fda6f272 TH |
252 | * Determine the associated throtl_data accordingly and return it. |
253 | */ | |
254 | static struct throtl_data *sq_to_td(struct throtl_service_queue *sq) | |
255 | { | |
256 | struct throtl_grp *tg = sq_to_tg(sq); | |
257 | ||
258 | if (tg) | |
259 | return tg->td; | |
260 | else | |
261 | return container_of(sq, struct throtl_data, service_queue); | |
262 | } | |
263 | ||
7394e31f SL |
264 | /* |
265 | * cgroup's limit in LIMIT_MAX is scaled if low limit is set. This scale is to | |
266 | * make the IO dispatch more smooth. | |
267 | * Scale up: linearly scale up according to lapsed time since upgrade. For | |
268 | * every throtl_slice, the limit scales up 1/2 .low limit till the | |
269 | * limit hits .max limit | |
270 | * Scale down: exponentially scale down if a cgroup doesn't hit its .low limit | |
271 | */ | |
272 | static uint64_t throtl_adjusted_limit(uint64_t low, struct throtl_data *td) | |
273 | { | |
274 | /* arbitrary value to avoid too big scale */ | |
275 | if (td->scale < 4096 && time_after_eq(jiffies, | |
276 | td->low_upgrade_time + td->scale * td->throtl_slice)) | |
277 | td->scale = (jiffies - td->low_upgrade_time) / td->throtl_slice; | |
278 | ||
279 | return low + (low >> 1) * td->scale; | |
280 | } | |
281 | ||
9f626e37 SL |
282 | static uint64_t tg_bps_limit(struct throtl_grp *tg, int rw) |
283 | { | |
b22c417c | 284 | struct blkcg_gq *blkg = tg_to_blkg(tg); |
7394e31f | 285 | struct throtl_data *td; |
b22c417c SL |
286 | uint64_t ret; |
287 | ||
288 | if (cgroup_subsys_on_dfl(io_cgrp_subsys) && !blkg->parent) | |
289 | return U64_MAX; | |
7394e31f SL |
290 | |
291 | td = tg->td; | |
292 | ret = tg->bps[rw][td->limit_index]; | |
293 | if (ret == 0 && td->limit_index == LIMIT_LOW) | |
b22c417c | 294 | return tg->bps[rw][LIMIT_MAX]; |
7394e31f SL |
295 | |
296 | if (td->limit_index == LIMIT_MAX && tg->bps[rw][LIMIT_LOW] && | |
297 | tg->bps[rw][LIMIT_LOW] != tg->bps[rw][LIMIT_MAX]) { | |
298 | uint64_t adjusted; | |
299 | ||
300 | adjusted = throtl_adjusted_limit(tg->bps[rw][LIMIT_LOW], td); | |
301 | ret = min(tg->bps[rw][LIMIT_MAX], adjusted); | |
302 | } | |
b22c417c | 303 | return ret; |
9f626e37 SL |
304 | } |
305 | ||
306 | static unsigned int tg_iops_limit(struct throtl_grp *tg, int rw) | |
307 | { | |
b22c417c | 308 | struct blkcg_gq *blkg = tg_to_blkg(tg); |
7394e31f | 309 | struct throtl_data *td; |
b22c417c SL |
310 | unsigned int ret; |
311 | ||
312 | if (cgroup_subsys_on_dfl(io_cgrp_subsys) && !blkg->parent) | |
313 | return UINT_MAX; | |
7394e31f SL |
314 | td = tg->td; |
315 | ret = tg->iops[rw][td->limit_index]; | |
b22c417c SL |
316 | if (ret == 0 && tg->td->limit_index == LIMIT_LOW) |
317 | return tg->iops[rw][LIMIT_MAX]; | |
7394e31f SL |
318 | |
319 | if (td->limit_index == LIMIT_MAX && tg->iops[rw][LIMIT_LOW] && | |
320 | tg->iops[rw][LIMIT_LOW] != tg->iops[rw][LIMIT_MAX]) { | |
321 | uint64_t adjusted; | |
322 | ||
323 | adjusted = throtl_adjusted_limit(tg->iops[rw][LIMIT_LOW], td); | |
324 | if (adjusted > UINT_MAX) | |
325 | adjusted = UINT_MAX; | |
326 | ret = min_t(unsigned int, tg->iops[rw][LIMIT_MAX], adjusted); | |
327 | } | |
b22c417c | 328 | return ret; |
9f626e37 SL |
329 | } |
330 | ||
b9147dd1 SL |
331 | #define request_bucket_index(sectors) \ |
332 | clamp_t(int, order_base_2(sectors) - 3, 0, LATENCY_BUCKET_SIZE - 1) | |
333 | ||
fda6f272 TH |
334 | /** |
335 | * throtl_log - log debug message via blktrace | |
336 | * @sq: the service_queue being reported | |
337 | * @fmt: printf format string | |
338 | * @args: printf args | |
339 | * | |
340 | * The messages are prefixed with "throtl BLKG_NAME" if @sq belongs to a | |
341 | * throtl_grp; otherwise, just "throtl". | |
fda6f272 TH |
342 | */ |
343 | #define throtl_log(sq, fmt, args...) do { \ | |
344 | struct throtl_grp *__tg = sq_to_tg((sq)); \ | |
345 | struct throtl_data *__td = sq_to_td((sq)); \ | |
346 | \ | |
347 | (void)__td; \ | |
59fa0224 SL |
348 | if (likely(!blk_trace_note_message_enabled(__td->queue))) \ |
349 | break; \ | |
fda6f272 TH |
350 | if ((__tg)) { \ |
351 | char __pbuf[128]; \ | |
54e7ed12 | 352 | \ |
fda6f272 TH |
353 | blkg_path(tg_to_blkg(__tg), __pbuf, sizeof(__pbuf)); \ |
354 | blk_add_trace_msg(__td->queue, "throtl %s " fmt, __pbuf, ##args); \ | |
355 | } else { \ | |
356 | blk_add_trace_msg(__td->queue, "throtl " fmt, ##args); \ | |
357 | } \ | |
54e7ed12 | 358 | } while (0) |
e43473b7 | 359 | |
c5cc2070 TH |
360 | static void throtl_qnode_init(struct throtl_qnode *qn, struct throtl_grp *tg) |
361 | { | |
362 | INIT_LIST_HEAD(&qn->node); | |
363 | bio_list_init(&qn->bios); | |
364 | qn->tg = tg; | |
365 | } | |
366 | ||
367 | /** | |
368 | * throtl_qnode_add_bio - add a bio to a throtl_qnode and activate it | |
369 | * @bio: bio being added | |
370 | * @qn: qnode to add bio to | |
371 | * @queued: the service_queue->queued[] list @qn belongs to | |
372 | * | |
373 | * Add @bio to @qn and put @qn on @queued if it's not already on. | |
374 | * @qn->tg's reference count is bumped when @qn is activated. See the | |
375 | * comment on top of throtl_qnode definition for details. | |
376 | */ | |
377 | static void throtl_qnode_add_bio(struct bio *bio, struct throtl_qnode *qn, | |
378 | struct list_head *queued) | |
379 | { | |
380 | bio_list_add(&qn->bios, bio); | |
381 | if (list_empty(&qn->node)) { | |
382 | list_add_tail(&qn->node, queued); | |
383 | blkg_get(tg_to_blkg(qn->tg)); | |
384 | } | |
385 | } | |
386 | ||
387 | /** | |
388 | * throtl_peek_queued - peek the first bio on a qnode list | |
389 | * @queued: the qnode list to peek | |
390 | */ | |
391 | static struct bio *throtl_peek_queued(struct list_head *queued) | |
392 | { | |
393 | struct throtl_qnode *qn = list_first_entry(queued, struct throtl_qnode, node); | |
394 | struct bio *bio; | |
395 | ||
396 | if (list_empty(queued)) | |
397 | return NULL; | |
398 | ||
399 | bio = bio_list_peek(&qn->bios); | |
400 | WARN_ON_ONCE(!bio); | |
401 | return bio; | |
402 | } | |
403 | ||
404 | /** | |
405 | * throtl_pop_queued - pop the first bio form a qnode list | |
406 | * @queued: the qnode list to pop a bio from | |
407 | * @tg_to_put: optional out argument for throtl_grp to put | |
408 | * | |
409 | * Pop the first bio from the qnode list @queued. After popping, the first | |
410 | * qnode is removed from @queued if empty or moved to the end of @queued so | |
411 | * that the popping order is round-robin. | |
412 | * | |
413 | * When the first qnode is removed, its associated throtl_grp should be put | |
414 | * too. If @tg_to_put is NULL, this function automatically puts it; | |
415 | * otherwise, *@tg_to_put is set to the throtl_grp to put and the caller is | |
416 | * responsible for putting it. | |
417 | */ | |
418 | static struct bio *throtl_pop_queued(struct list_head *queued, | |
419 | struct throtl_grp **tg_to_put) | |
420 | { | |
421 | struct throtl_qnode *qn = list_first_entry(queued, struct throtl_qnode, node); | |
422 | struct bio *bio; | |
423 | ||
424 | if (list_empty(queued)) | |
425 | return NULL; | |
426 | ||
427 | bio = bio_list_pop(&qn->bios); | |
428 | WARN_ON_ONCE(!bio); | |
429 | ||
430 | if (bio_list_empty(&qn->bios)) { | |
431 | list_del_init(&qn->node); | |
432 | if (tg_to_put) | |
433 | *tg_to_put = qn->tg; | |
434 | else | |
435 | blkg_put(tg_to_blkg(qn->tg)); | |
436 | } else { | |
437 | list_move_tail(&qn->node, queued); | |
438 | } | |
439 | ||
440 | return bio; | |
441 | } | |
442 | ||
49a2f1e3 | 443 | /* init a service_queue, assumes the caller zeroed it */ |
b2ce2643 | 444 | static void throtl_service_queue_init(struct throtl_service_queue *sq) |
49a2f1e3 | 445 | { |
c5cc2070 TH |
446 | INIT_LIST_HEAD(&sq->queued[0]); |
447 | INIT_LIST_HEAD(&sq->queued[1]); | |
49a2f1e3 | 448 | sq->pending_tree = RB_ROOT; |
69df0ab0 TH |
449 | setup_timer(&sq->pending_timer, throtl_pending_timer_fn, |
450 | (unsigned long)sq); | |
451 | } | |
452 | ||
001bea73 TH |
453 | static struct blkg_policy_data *throtl_pd_alloc(gfp_t gfp, int node) |
454 | { | |
4fb72036 | 455 | struct throtl_grp *tg; |
24bdb8ef | 456 | int rw; |
4fb72036 TH |
457 | |
458 | tg = kzalloc_node(sizeof(*tg), gfp, node); | |
459 | if (!tg) | |
77ea7338 | 460 | return NULL; |
4fb72036 | 461 | |
b2ce2643 TH |
462 | throtl_service_queue_init(&tg->service_queue); |
463 | ||
464 | for (rw = READ; rw <= WRITE; rw++) { | |
465 | throtl_qnode_init(&tg->qnode_on_self[rw], tg); | |
466 | throtl_qnode_init(&tg->qnode_on_parent[rw], tg); | |
467 | } | |
468 | ||
469 | RB_CLEAR_NODE(&tg->rb_node); | |
9f626e37 SL |
470 | tg->bps[READ][LIMIT_MAX] = U64_MAX; |
471 | tg->bps[WRITE][LIMIT_MAX] = U64_MAX; | |
472 | tg->iops[READ][LIMIT_MAX] = UINT_MAX; | |
473 | tg->iops[WRITE][LIMIT_MAX] = UINT_MAX; | |
cd5ab1b0 SL |
474 | tg->bps_conf[READ][LIMIT_MAX] = U64_MAX; |
475 | tg->bps_conf[WRITE][LIMIT_MAX] = U64_MAX; | |
476 | tg->iops_conf[READ][LIMIT_MAX] = UINT_MAX; | |
477 | tg->iops_conf[WRITE][LIMIT_MAX] = UINT_MAX; | |
478 | /* LIMIT_LOW will have default value 0 */ | |
b2ce2643 | 479 | |
ec80991d SL |
480 | tg->latency_target = DFL_LATENCY_TARGET; |
481 | ||
4fb72036 | 482 | return &tg->pd; |
001bea73 TH |
483 | } |
484 | ||
a9520cd6 | 485 | static void throtl_pd_init(struct blkg_policy_data *pd) |
a29a171e | 486 | { |
a9520cd6 TH |
487 | struct throtl_grp *tg = pd_to_tg(pd); |
488 | struct blkcg_gq *blkg = tg_to_blkg(tg); | |
77216b04 | 489 | struct throtl_data *td = blkg->q->td; |
b2ce2643 | 490 | struct throtl_service_queue *sq = &tg->service_queue; |
cd1604fa | 491 | |
9138125b | 492 | /* |
aa6ec29b | 493 | * If on the default hierarchy, we switch to properly hierarchical |
9138125b TH |
494 | * behavior where limits on a given throtl_grp are applied to the |
495 | * whole subtree rather than just the group itself. e.g. If 16M | |
496 | * read_bps limit is set on the root group, the whole system can't | |
497 | * exceed 16M for the device. | |
498 | * | |
aa6ec29b | 499 | * If not on the default hierarchy, the broken flat hierarchy |
9138125b TH |
500 | * behavior is retained where all throtl_grps are treated as if |
501 | * they're all separate root groups right below throtl_data. | |
502 | * Limits of a group don't interact with limits of other groups | |
503 | * regardless of the position of the group in the hierarchy. | |
504 | */ | |
b2ce2643 | 505 | sq->parent_sq = &td->service_queue; |
9e10a130 | 506 | if (cgroup_subsys_on_dfl(io_cgrp_subsys) && blkg->parent) |
b2ce2643 | 507 | sq->parent_sq = &blkg_to_tg(blkg->parent)->service_queue; |
77216b04 | 508 | tg->td = td; |
9e234eea | 509 | |
ada75b6e | 510 | tg->idletime_threshold = td->dft_idletime_threshold; |
8a3d2615 TH |
511 | } |
512 | ||
693e751e TH |
513 | /* |
514 | * Set has_rules[] if @tg or any of its parents have limits configured. | |
515 | * This doesn't require walking up to the top of the hierarchy as the | |
516 | * parent's has_rules[] is guaranteed to be correct. | |
517 | */ | |
518 | static void tg_update_has_rules(struct throtl_grp *tg) | |
519 | { | |
520 | struct throtl_grp *parent_tg = sq_to_tg(tg->service_queue.parent_sq); | |
9f626e37 | 521 | struct throtl_data *td = tg->td; |
693e751e TH |
522 | int rw; |
523 | ||
524 | for (rw = READ; rw <= WRITE; rw++) | |
525 | tg->has_rules[rw] = (parent_tg && parent_tg->has_rules[rw]) || | |
9f626e37 SL |
526 | (td->limit_valid[td->limit_index] && |
527 | (tg_bps_limit(tg, rw) != U64_MAX || | |
528 | tg_iops_limit(tg, rw) != UINT_MAX)); | |
693e751e TH |
529 | } |
530 | ||
a9520cd6 | 531 | static void throtl_pd_online(struct blkg_policy_data *pd) |
693e751e | 532 | { |
aec24246 | 533 | struct throtl_grp *tg = pd_to_tg(pd); |
693e751e TH |
534 | /* |
535 | * We don't want new groups to escape the limits of its ancestors. | |
536 | * Update has_rules[] after a new group is brought online. | |
537 | */ | |
aec24246 | 538 | tg_update_has_rules(tg); |
693e751e TH |
539 | } |
540 | ||
cd5ab1b0 SL |
541 | static void blk_throtl_update_limit_valid(struct throtl_data *td) |
542 | { | |
543 | struct cgroup_subsys_state *pos_css; | |
544 | struct blkcg_gq *blkg; | |
545 | bool low_valid = false; | |
546 | ||
547 | rcu_read_lock(); | |
548 | blkg_for_each_descendant_post(blkg, pos_css, td->queue->root_blkg) { | |
549 | struct throtl_grp *tg = blkg_to_tg(blkg); | |
550 | ||
551 | if (tg->bps[READ][LIMIT_LOW] || tg->bps[WRITE][LIMIT_LOW] || | |
552 | tg->iops[READ][LIMIT_LOW] || tg->iops[WRITE][LIMIT_LOW]) | |
553 | low_valid = true; | |
554 | } | |
555 | rcu_read_unlock(); | |
556 | ||
557 | td->limit_valid[LIMIT_LOW] = low_valid; | |
558 | } | |
559 | ||
c79892c5 | 560 | static void throtl_upgrade_state(struct throtl_data *td); |
cd5ab1b0 SL |
561 | static void throtl_pd_offline(struct blkg_policy_data *pd) |
562 | { | |
563 | struct throtl_grp *tg = pd_to_tg(pd); | |
564 | ||
565 | tg->bps[READ][LIMIT_LOW] = 0; | |
566 | tg->bps[WRITE][LIMIT_LOW] = 0; | |
567 | tg->iops[READ][LIMIT_LOW] = 0; | |
568 | tg->iops[WRITE][LIMIT_LOW] = 0; | |
569 | ||
570 | blk_throtl_update_limit_valid(tg->td); | |
571 | ||
c79892c5 SL |
572 | if (!tg->td->limit_valid[tg->td->limit_index]) |
573 | throtl_upgrade_state(tg->td); | |
cd5ab1b0 SL |
574 | } |
575 | ||
001bea73 TH |
576 | static void throtl_pd_free(struct blkg_policy_data *pd) |
577 | { | |
4fb72036 TH |
578 | struct throtl_grp *tg = pd_to_tg(pd); |
579 | ||
b2ce2643 | 580 | del_timer_sync(&tg->service_queue.pending_timer); |
4fb72036 | 581 | kfree(tg); |
001bea73 TH |
582 | } |
583 | ||
0049af73 TH |
584 | static struct throtl_grp * |
585 | throtl_rb_first(struct throtl_service_queue *parent_sq) | |
e43473b7 VG |
586 | { |
587 | /* Service tree is empty */ | |
0049af73 | 588 | if (!parent_sq->nr_pending) |
e43473b7 VG |
589 | return NULL; |
590 | ||
0049af73 TH |
591 | if (!parent_sq->first_pending) |
592 | parent_sq->first_pending = rb_first(&parent_sq->pending_tree); | |
e43473b7 | 593 | |
0049af73 TH |
594 | if (parent_sq->first_pending) |
595 | return rb_entry_tg(parent_sq->first_pending); | |
e43473b7 VG |
596 | |
597 | return NULL; | |
598 | } | |
599 | ||
600 | static void rb_erase_init(struct rb_node *n, struct rb_root *root) | |
601 | { | |
602 | rb_erase(n, root); | |
603 | RB_CLEAR_NODE(n); | |
604 | } | |
605 | ||
0049af73 TH |
606 | static void throtl_rb_erase(struct rb_node *n, |
607 | struct throtl_service_queue *parent_sq) | |
e43473b7 | 608 | { |
0049af73 TH |
609 | if (parent_sq->first_pending == n) |
610 | parent_sq->first_pending = NULL; | |
611 | rb_erase_init(n, &parent_sq->pending_tree); | |
612 | --parent_sq->nr_pending; | |
e43473b7 VG |
613 | } |
614 | ||
0049af73 | 615 | static void update_min_dispatch_time(struct throtl_service_queue *parent_sq) |
e43473b7 VG |
616 | { |
617 | struct throtl_grp *tg; | |
618 | ||
0049af73 | 619 | tg = throtl_rb_first(parent_sq); |
e43473b7 VG |
620 | if (!tg) |
621 | return; | |
622 | ||
0049af73 | 623 | parent_sq->first_pending_disptime = tg->disptime; |
e43473b7 VG |
624 | } |
625 | ||
77216b04 | 626 | static void tg_service_queue_add(struct throtl_grp *tg) |
e43473b7 | 627 | { |
77216b04 | 628 | struct throtl_service_queue *parent_sq = tg->service_queue.parent_sq; |
0049af73 | 629 | struct rb_node **node = &parent_sq->pending_tree.rb_node; |
e43473b7 VG |
630 | struct rb_node *parent = NULL; |
631 | struct throtl_grp *__tg; | |
632 | unsigned long key = tg->disptime; | |
633 | int left = 1; | |
634 | ||
635 | while (*node != NULL) { | |
636 | parent = *node; | |
637 | __tg = rb_entry_tg(parent); | |
638 | ||
639 | if (time_before(key, __tg->disptime)) | |
640 | node = &parent->rb_left; | |
641 | else { | |
642 | node = &parent->rb_right; | |
643 | left = 0; | |
644 | } | |
645 | } | |
646 | ||
647 | if (left) | |
0049af73 | 648 | parent_sq->first_pending = &tg->rb_node; |
e43473b7 VG |
649 | |
650 | rb_link_node(&tg->rb_node, parent, node); | |
0049af73 | 651 | rb_insert_color(&tg->rb_node, &parent_sq->pending_tree); |
e43473b7 VG |
652 | } |
653 | ||
77216b04 | 654 | static void __throtl_enqueue_tg(struct throtl_grp *tg) |
e43473b7 | 655 | { |
77216b04 | 656 | tg_service_queue_add(tg); |
5b2c16aa | 657 | tg->flags |= THROTL_TG_PENDING; |
77216b04 | 658 | tg->service_queue.parent_sq->nr_pending++; |
e43473b7 VG |
659 | } |
660 | ||
77216b04 | 661 | static void throtl_enqueue_tg(struct throtl_grp *tg) |
e43473b7 | 662 | { |
5b2c16aa | 663 | if (!(tg->flags & THROTL_TG_PENDING)) |
77216b04 | 664 | __throtl_enqueue_tg(tg); |
e43473b7 VG |
665 | } |
666 | ||
77216b04 | 667 | static void __throtl_dequeue_tg(struct throtl_grp *tg) |
e43473b7 | 668 | { |
77216b04 | 669 | throtl_rb_erase(&tg->rb_node, tg->service_queue.parent_sq); |
5b2c16aa | 670 | tg->flags &= ~THROTL_TG_PENDING; |
e43473b7 VG |
671 | } |
672 | ||
77216b04 | 673 | static void throtl_dequeue_tg(struct throtl_grp *tg) |
e43473b7 | 674 | { |
5b2c16aa | 675 | if (tg->flags & THROTL_TG_PENDING) |
77216b04 | 676 | __throtl_dequeue_tg(tg); |
e43473b7 VG |
677 | } |
678 | ||
a9131a27 | 679 | /* Call with queue lock held */ |
69df0ab0 TH |
680 | static void throtl_schedule_pending_timer(struct throtl_service_queue *sq, |
681 | unsigned long expires) | |
a9131a27 | 682 | { |
297e3d85 | 683 | unsigned long max_expire = jiffies + 8 * sq_to_tg(sq)->td->throtl_slice; |
06cceedc SL |
684 | |
685 | /* | |
686 | * Since we are adjusting the throttle limit dynamically, the sleep | |
687 | * time calculated according to previous limit might be invalid. It's | |
688 | * possible the cgroup sleep time is very long and no other cgroups | |
689 | * have IO running so notify the limit changes. Make sure the cgroup | |
690 | * doesn't sleep too long to avoid the missed notification. | |
691 | */ | |
692 | if (time_after(expires, max_expire)) | |
693 | expires = max_expire; | |
69df0ab0 TH |
694 | mod_timer(&sq->pending_timer, expires); |
695 | throtl_log(sq, "schedule timer. delay=%lu jiffies=%lu", | |
696 | expires - jiffies, jiffies); | |
a9131a27 TH |
697 | } |
698 | ||
7f52f98c TH |
699 | /** |
700 | * throtl_schedule_next_dispatch - schedule the next dispatch cycle | |
701 | * @sq: the service_queue to schedule dispatch for | |
702 | * @force: force scheduling | |
703 | * | |
704 | * Arm @sq->pending_timer so that the next dispatch cycle starts on the | |
705 | * dispatch time of the first pending child. Returns %true if either timer | |
706 | * is armed or there's no pending child left. %false if the current | |
707 | * dispatch window is still open and the caller should continue | |
708 | * dispatching. | |
709 | * | |
710 | * If @force is %true, the dispatch timer is always scheduled and this | |
711 | * function is guaranteed to return %true. This is to be used when the | |
712 | * caller can't dispatch itself and needs to invoke pending_timer | |
713 | * unconditionally. Note that forced scheduling is likely to induce short | |
714 | * delay before dispatch starts even if @sq->first_pending_disptime is not | |
715 | * in the future and thus shouldn't be used in hot paths. | |
716 | */ | |
717 | static bool throtl_schedule_next_dispatch(struct throtl_service_queue *sq, | |
718 | bool force) | |
e43473b7 | 719 | { |
6a525600 | 720 | /* any pending children left? */ |
c9e0332e | 721 | if (!sq->nr_pending) |
7f52f98c | 722 | return true; |
e43473b7 | 723 | |
c9e0332e | 724 | update_min_dispatch_time(sq); |
e43473b7 | 725 | |
69df0ab0 | 726 | /* is the next dispatch time in the future? */ |
7f52f98c | 727 | if (force || time_after(sq->first_pending_disptime, jiffies)) { |
69df0ab0 | 728 | throtl_schedule_pending_timer(sq, sq->first_pending_disptime); |
7f52f98c | 729 | return true; |
69df0ab0 TH |
730 | } |
731 | ||
7f52f98c TH |
732 | /* tell the caller to continue dispatching */ |
733 | return false; | |
e43473b7 VG |
734 | } |
735 | ||
32ee5bc4 VG |
736 | static inline void throtl_start_new_slice_with_credit(struct throtl_grp *tg, |
737 | bool rw, unsigned long start) | |
738 | { | |
739 | tg->bytes_disp[rw] = 0; | |
740 | tg->io_disp[rw] = 0; | |
741 | ||
742 | /* | |
743 | * Previous slice has expired. We must have trimmed it after last | |
744 | * bio dispatch. That means since start of last slice, we never used | |
745 | * that bandwidth. Do try to make use of that bandwidth while giving | |
746 | * credit. | |
747 | */ | |
748 | if (time_after_eq(start, tg->slice_start[rw])) | |
749 | tg->slice_start[rw] = start; | |
750 | ||
297e3d85 | 751 | tg->slice_end[rw] = jiffies + tg->td->throtl_slice; |
32ee5bc4 VG |
752 | throtl_log(&tg->service_queue, |
753 | "[%c] new slice with credit start=%lu end=%lu jiffies=%lu", | |
754 | rw == READ ? 'R' : 'W', tg->slice_start[rw], | |
755 | tg->slice_end[rw], jiffies); | |
756 | } | |
757 | ||
0f3457f6 | 758 | static inline void throtl_start_new_slice(struct throtl_grp *tg, bool rw) |
e43473b7 VG |
759 | { |
760 | tg->bytes_disp[rw] = 0; | |
8e89d13f | 761 | tg->io_disp[rw] = 0; |
e43473b7 | 762 | tg->slice_start[rw] = jiffies; |
297e3d85 | 763 | tg->slice_end[rw] = jiffies + tg->td->throtl_slice; |
fda6f272 TH |
764 | throtl_log(&tg->service_queue, |
765 | "[%c] new slice start=%lu end=%lu jiffies=%lu", | |
766 | rw == READ ? 'R' : 'W', tg->slice_start[rw], | |
767 | tg->slice_end[rw], jiffies); | |
e43473b7 VG |
768 | } |
769 | ||
0f3457f6 TH |
770 | static inline void throtl_set_slice_end(struct throtl_grp *tg, bool rw, |
771 | unsigned long jiffy_end) | |
d1ae8ffd | 772 | { |
297e3d85 | 773 | tg->slice_end[rw] = roundup(jiffy_end, tg->td->throtl_slice); |
d1ae8ffd VG |
774 | } |
775 | ||
0f3457f6 TH |
776 | static inline void throtl_extend_slice(struct throtl_grp *tg, bool rw, |
777 | unsigned long jiffy_end) | |
e43473b7 | 778 | { |
297e3d85 | 779 | tg->slice_end[rw] = roundup(jiffy_end, tg->td->throtl_slice); |
fda6f272 TH |
780 | throtl_log(&tg->service_queue, |
781 | "[%c] extend slice start=%lu end=%lu jiffies=%lu", | |
782 | rw == READ ? 'R' : 'W', tg->slice_start[rw], | |
783 | tg->slice_end[rw], jiffies); | |
e43473b7 VG |
784 | } |
785 | ||
786 | /* Determine if previously allocated or extended slice is complete or not */ | |
0f3457f6 | 787 | static bool throtl_slice_used(struct throtl_grp *tg, bool rw) |
e43473b7 VG |
788 | { |
789 | if (time_in_range(jiffies, tg->slice_start[rw], tg->slice_end[rw])) | |
5cf8c227 | 790 | return false; |
e43473b7 VG |
791 | |
792 | return 1; | |
793 | } | |
794 | ||
795 | /* Trim the used slices and adjust slice start accordingly */ | |
0f3457f6 | 796 | static inline void throtl_trim_slice(struct throtl_grp *tg, bool rw) |
e43473b7 | 797 | { |
3aad5d3e VG |
798 | unsigned long nr_slices, time_elapsed, io_trim; |
799 | u64 bytes_trim, tmp; | |
e43473b7 VG |
800 | |
801 | BUG_ON(time_before(tg->slice_end[rw], tg->slice_start[rw])); | |
802 | ||
803 | /* | |
804 | * If bps are unlimited (-1), then time slice don't get | |
805 | * renewed. Don't try to trim the slice if slice is used. A new | |
806 | * slice will start when appropriate. | |
807 | */ | |
0f3457f6 | 808 | if (throtl_slice_used(tg, rw)) |
e43473b7 VG |
809 | return; |
810 | ||
d1ae8ffd VG |
811 | /* |
812 | * A bio has been dispatched. Also adjust slice_end. It might happen | |
813 | * that initially cgroup limit was very low resulting in high | |
814 | * slice_end, but later limit was bumped up and bio was dispached | |
815 | * sooner, then we need to reduce slice_end. A high bogus slice_end | |
816 | * is bad because it does not allow new slice to start. | |
817 | */ | |
818 | ||
297e3d85 | 819 | throtl_set_slice_end(tg, rw, jiffies + tg->td->throtl_slice); |
d1ae8ffd | 820 | |
e43473b7 VG |
821 | time_elapsed = jiffies - tg->slice_start[rw]; |
822 | ||
297e3d85 | 823 | nr_slices = time_elapsed / tg->td->throtl_slice; |
e43473b7 VG |
824 | |
825 | if (!nr_slices) | |
826 | return; | |
297e3d85 | 827 | tmp = tg_bps_limit(tg, rw) * tg->td->throtl_slice * nr_slices; |
3aad5d3e VG |
828 | do_div(tmp, HZ); |
829 | bytes_trim = tmp; | |
e43473b7 | 830 | |
297e3d85 SL |
831 | io_trim = (tg_iops_limit(tg, rw) * tg->td->throtl_slice * nr_slices) / |
832 | HZ; | |
e43473b7 | 833 | |
8e89d13f | 834 | if (!bytes_trim && !io_trim) |
e43473b7 VG |
835 | return; |
836 | ||
837 | if (tg->bytes_disp[rw] >= bytes_trim) | |
838 | tg->bytes_disp[rw] -= bytes_trim; | |
839 | else | |
840 | tg->bytes_disp[rw] = 0; | |
841 | ||
8e89d13f VG |
842 | if (tg->io_disp[rw] >= io_trim) |
843 | tg->io_disp[rw] -= io_trim; | |
844 | else | |
845 | tg->io_disp[rw] = 0; | |
846 | ||
297e3d85 | 847 | tg->slice_start[rw] += nr_slices * tg->td->throtl_slice; |
e43473b7 | 848 | |
fda6f272 TH |
849 | throtl_log(&tg->service_queue, |
850 | "[%c] trim slice nr=%lu bytes=%llu io=%lu start=%lu end=%lu jiffies=%lu", | |
851 | rw == READ ? 'R' : 'W', nr_slices, bytes_trim, io_trim, | |
852 | tg->slice_start[rw], tg->slice_end[rw], jiffies); | |
e43473b7 VG |
853 | } |
854 | ||
0f3457f6 TH |
855 | static bool tg_with_in_iops_limit(struct throtl_grp *tg, struct bio *bio, |
856 | unsigned long *wait) | |
e43473b7 VG |
857 | { |
858 | bool rw = bio_data_dir(bio); | |
8e89d13f | 859 | unsigned int io_allowed; |
e43473b7 | 860 | unsigned long jiffy_elapsed, jiffy_wait, jiffy_elapsed_rnd; |
c49c06e4 | 861 | u64 tmp; |
e43473b7 | 862 | |
8e89d13f | 863 | jiffy_elapsed = jiffy_elapsed_rnd = jiffies - tg->slice_start[rw]; |
e43473b7 | 864 | |
8e89d13f VG |
865 | /* Slice has just started. Consider one slice interval */ |
866 | if (!jiffy_elapsed) | |
297e3d85 | 867 | jiffy_elapsed_rnd = tg->td->throtl_slice; |
8e89d13f | 868 | |
297e3d85 | 869 | jiffy_elapsed_rnd = roundup(jiffy_elapsed_rnd, tg->td->throtl_slice); |
8e89d13f | 870 | |
c49c06e4 VG |
871 | /* |
872 | * jiffy_elapsed_rnd should not be a big value as minimum iops can be | |
873 | * 1 then at max jiffy elapsed should be equivalent of 1 second as we | |
874 | * will allow dispatch after 1 second and after that slice should | |
875 | * have been trimmed. | |
876 | */ | |
877 | ||
9f626e37 | 878 | tmp = (u64)tg_iops_limit(tg, rw) * jiffy_elapsed_rnd; |
c49c06e4 VG |
879 | do_div(tmp, HZ); |
880 | ||
881 | if (tmp > UINT_MAX) | |
882 | io_allowed = UINT_MAX; | |
883 | else | |
884 | io_allowed = tmp; | |
8e89d13f VG |
885 | |
886 | if (tg->io_disp[rw] + 1 <= io_allowed) { | |
e43473b7 VG |
887 | if (wait) |
888 | *wait = 0; | |
5cf8c227 | 889 | return true; |
e43473b7 VG |
890 | } |
891 | ||
8e89d13f | 892 | /* Calc approx time to dispatch */ |
9f626e37 | 893 | jiffy_wait = ((tg->io_disp[rw] + 1) * HZ) / tg_iops_limit(tg, rw) + 1; |
8e89d13f VG |
894 | |
895 | if (jiffy_wait > jiffy_elapsed) | |
896 | jiffy_wait = jiffy_wait - jiffy_elapsed; | |
897 | else | |
898 | jiffy_wait = 1; | |
899 | ||
900 | if (wait) | |
901 | *wait = jiffy_wait; | |
902 | return 0; | |
903 | } | |
904 | ||
0f3457f6 TH |
905 | static bool tg_with_in_bps_limit(struct throtl_grp *tg, struct bio *bio, |
906 | unsigned long *wait) | |
8e89d13f VG |
907 | { |
908 | bool rw = bio_data_dir(bio); | |
3aad5d3e | 909 | u64 bytes_allowed, extra_bytes, tmp; |
8e89d13f | 910 | unsigned long jiffy_elapsed, jiffy_wait, jiffy_elapsed_rnd; |
e43473b7 VG |
911 | |
912 | jiffy_elapsed = jiffy_elapsed_rnd = jiffies - tg->slice_start[rw]; | |
913 | ||
914 | /* Slice has just started. Consider one slice interval */ | |
915 | if (!jiffy_elapsed) | |
297e3d85 | 916 | jiffy_elapsed_rnd = tg->td->throtl_slice; |
e43473b7 | 917 | |
297e3d85 | 918 | jiffy_elapsed_rnd = roundup(jiffy_elapsed_rnd, tg->td->throtl_slice); |
e43473b7 | 919 | |
9f626e37 | 920 | tmp = tg_bps_limit(tg, rw) * jiffy_elapsed_rnd; |
5e901a2b | 921 | do_div(tmp, HZ); |
3aad5d3e | 922 | bytes_allowed = tmp; |
e43473b7 | 923 | |
4f024f37 | 924 | if (tg->bytes_disp[rw] + bio->bi_iter.bi_size <= bytes_allowed) { |
e43473b7 VG |
925 | if (wait) |
926 | *wait = 0; | |
5cf8c227 | 927 | return true; |
e43473b7 VG |
928 | } |
929 | ||
930 | /* Calc approx time to dispatch */ | |
4f024f37 | 931 | extra_bytes = tg->bytes_disp[rw] + bio->bi_iter.bi_size - bytes_allowed; |
9f626e37 | 932 | jiffy_wait = div64_u64(extra_bytes * HZ, tg_bps_limit(tg, rw)); |
e43473b7 VG |
933 | |
934 | if (!jiffy_wait) | |
935 | jiffy_wait = 1; | |
936 | ||
937 | /* | |
938 | * This wait time is without taking into consideration the rounding | |
939 | * up we did. Add that time also. | |
940 | */ | |
941 | jiffy_wait = jiffy_wait + (jiffy_elapsed_rnd - jiffy_elapsed); | |
e43473b7 VG |
942 | if (wait) |
943 | *wait = jiffy_wait; | |
8e89d13f VG |
944 | return 0; |
945 | } | |
946 | ||
947 | /* | |
948 | * Returns whether one can dispatch a bio or not. Also returns approx number | |
949 | * of jiffies to wait before this bio is with-in IO rate and can be dispatched | |
950 | */ | |
0f3457f6 TH |
951 | static bool tg_may_dispatch(struct throtl_grp *tg, struct bio *bio, |
952 | unsigned long *wait) | |
8e89d13f VG |
953 | { |
954 | bool rw = bio_data_dir(bio); | |
955 | unsigned long bps_wait = 0, iops_wait = 0, max_wait = 0; | |
956 | ||
957 | /* | |
958 | * Currently whole state machine of group depends on first bio | |
959 | * queued in the group bio list. So one should not be calling | |
960 | * this function with a different bio if there are other bios | |
961 | * queued. | |
962 | */ | |
73f0d49a | 963 | BUG_ON(tg->service_queue.nr_queued[rw] && |
c5cc2070 | 964 | bio != throtl_peek_queued(&tg->service_queue.queued[rw])); |
e43473b7 | 965 | |
8e89d13f | 966 | /* If tg->bps = -1, then BW is unlimited */ |
9f626e37 SL |
967 | if (tg_bps_limit(tg, rw) == U64_MAX && |
968 | tg_iops_limit(tg, rw) == UINT_MAX) { | |
8e89d13f VG |
969 | if (wait) |
970 | *wait = 0; | |
5cf8c227 | 971 | return true; |
8e89d13f VG |
972 | } |
973 | ||
974 | /* | |
975 | * If previous slice expired, start a new one otherwise renew/extend | |
976 | * existing slice to make sure it is at least throtl_slice interval | |
164c80ed VG |
977 | * long since now. New slice is started only for empty throttle group. |
978 | * If there is queued bio, that means there should be an active | |
979 | * slice and it should be extended instead. | |
8e89d13f | 980 | */ |
164c80ed | 981 | if (throtl_slice_used(tg, rw) && !(tg->service_queue.nr_queued[rw])) |
0f3457f6 | 982 | throtl_start_new_slice(tg, rw); |
8e89d13f | 983 | else { |
297e3d85 SL |
984 | if (time_before(tg->slice_end[rw], |
985 | jiffies + tg->td->throtl_slice)) | |
986 | throtl_extend_slice(tg, rw, | |
987 | jiffies + tg->td->throtl_slice); | |
8e89d13f VG |
988 | } |
989 | ||
0f3457f6 TH |
990 | if (tg_with_in_bps_limit(tg, bio, &bps_wait) && |
991 | tg_with_in_iops_limit(tg, bio, &iops_wait)) { | |
8e89d13f VG |
992 | if (wait) |
993 | *wait = 0; | |
994 | return 1; | |
995 | } | |
996 | ||
997 | max_wait = max(bps_wait, iops_wait); | |
998 | ||
999 | if (wait) | |
1000 | *wait = max_wait; | |
1001 | ||
1002 | if (time_before(tg->slice_end[rw], jiffies + max_wait)) | |
0f3457f6 | 1003 | throtl_extend_slice(tg, rw, jiffies + max_wait); |
e43473b7 VG |
1004 | |
1005 | return 0; | |
1006 | } | |
1007 | ||
1008 | static void throtl_charge_bio(struct throtl_grp *tg, struct bio *bio) | |
1009 | { | |
1010 | bool rw = bio_data_dir(bio); | |
e43473b7 VG |
1011 | |
1012 | /* Charge the bio to the group */ | |
4f024f37 | 1013 | tg->bytes_disp[rw] += bio->bi_iter.bi_size; |
8e89d13f | 1014 | tg->io_disp[rw]++; |
3f0abd80 SL |
1015 | tg->last_bytes_disp[rw] += bio->bi_iter.bi_size; |
1016 | tg->last_io_disp[rw]++; | |
e43473b7 | 1017 | |
2a0f61e6 | 1018 | /* |
8d2bbd4c | 1019 | * BIO_THROTTLED is used to prevent the same bio to be throttled |
2a0f61e6 TH |
1020 | * more than once as a throttled bio will go through blk-throtl the |
1021 | * second time when it eventually gets issued. Set it when a bio | |
1022 | * is being charged to a tg. | |
2a0f61e6 | 1023 | */ |
8d2bbd4c CH |
1024 | if (!bio_flagged(bio, BIO_THROTTLED)) |
1025 | bio_set_flag(bio, BIO_THROTTLED); | |
e43473b7 VG |
1026 | } |
1027 | ||
c5cc2070 TH |
1028 | /** |
1029 | * throtl_add_bio_tg - add a bio to the specified throtl_grp | |
1030 | * @bio: bio to add | |
1031 | * @qn: qnode to use | |
1032 | * @tg: the target throtl_grp | |
1033 | * | |
1034 | * Add @bio to @tg's service_queue using @qn. If @qn is not specified, | |
1035 | * tg->qnode_on_self[] is used. | |
1036 | */ | |
1037 | static void throtl_add_bio_tg(struct bio *bio, struct throtl_qnode *qn, | |
1038 | struct throtl_grp *tg) | |
e43473b7 | 1039 | { |
73f0d49a | 1040 | struct throtl_service_queue *sq = &tg->service_queue; |
e43473b7 VG |
1041 | bool rw = bio_data_dir(bio); |
1042 | ||
c5cc2070 TH |
1043 | if (!qn) |
1044 | qn = &tg->qnode_on_self[rw]; | |
1045 | ||
0e9f4164 TH |
1046 | /* |
1047 | * If @tg doesn't currently have any bios queued in the same | |
1048 | * direction, queueing @bio can change when @tg should be | |
1049 | * dispatched. Mark that @tg was empty. This is automatically | |
1050 | * cleaered on the next tg_update_disptime(). | |
1051 | */ | |
1052 | if (!sq->nr_queued[rw]) | |
1053 | tg->flags |= THROTL_TG_WAS_EMPTY; | |
1054 | ||
c5cc2070 TH |
1055 | throtl_qnode_add_bio(bio, qn, &sq->queued[rw]); |
1056 | ||
73f0d49a | 1057 | sq->nr_queued[rw]++; |
77216b04 | 1058 | throtl_enqueue_tg(tg); |
e43473b7 VG |
1059 | } |
1060 | ||
77216b04 | 1061 | static void tg_update_disptime(struct throtl_grp *tg) |
e43473b7 | 1062 | { |
73f0d49a | 1063 | struct throtl_service_queue *sq = &tg->service_queue; |
e43473b7 VG |
1064 | unsigned long read_wait = -1, write_wait = -1, min_wait = -1, disptime; |
1065 | struct bio *bio; | |
1066 | ||
d609af3a ME |
1067 | bio = throtl_peek_queued(&sq->queued[READ]); |
1068 | if (bio) | |
0f3457f6 | 1069 | tg_may_dispatch(tg, bio, &read_wait); |
e43473b7 | 1070 | |
d609af3a ME |
1071 | bio = throtl_peek_queued(&sq->queued[WRITE]); |
1072 | if (bio) | |
0f3457f6 | 1073 | tg_may_dispatch(tg, bio, &write_wait); |
e43473b7 VG |
1074 | |
1075 | min_wait = min(read_wait, write_wait); | |
1076 | disptime = jiffies + min_wait; | |
1077 | ||
e43473b7 | 1078 | /* Update dispatch time */ |
77216b04 | 1079 | throtl_dequeue_tg(tg); |
e43473b7 | 1080 | tg->disptime = disptime; |
77216b04 | 1081 | throtl_enqueue_tg(tg); |
0e9f4164 TH |
1082 | |
1083 | /* see throtl_add_bio_tg() */ | |
1084 | tg->flags &= ~THROTL_TG_WAS_EMPTY; | |
e43473b7 VG |
1085 | } |
1086 | ||
32ee5bc4 VG |
1087 | static void start_parent_slice_with_credit(struct throtl_grp *child_tg, |
1088 | struct throtl_grp *parent_tg, bool rw) | |
1089 | { | |
1090 | if (throtl_slice_used(parent_tg, rw)) { | |
1091 | throtl_start_new_slice_with_credit(parent_tg, rw, | |
1092 | child_tg->slice_start[rw]); | |
1093 | } | |
1094 | ||
1095 | } | |
1096 | ||
77216b04 | 1097 | static void tg_dispatch_one_bio(struct throtl_grp *tg, bool rw) |
e43473b7 | 1098 | { |
73f0d49a | 1099 | struct throtl_service_queue *sq = &tg->service_queue; |
6bc9c2b4 TH |
1100 | struct throtl_service_queue *parent_sq = sq->parent_sq; |
1101 | struct throtl_grp *parent_tg = sq_to_tg(parent_sq); | |
c5cc2070 | 1102 | struct throtl_grp *tg_to_put = NULL; |
e43473b7 VG |
1103 | struct bio *bio; |
1104 | ||
c5cc2070 TH |
1105 | /* |
1106 | * @bio is being transferred from @tg to @parent_sq. Popping a bio | |
1107 | * from @tg may put its reference and @parent_sq might end up | |
1108 | * getting released prematurely. Remember the tg to put and put it | |
1109 | * after @bio is transferred to @parent_sq. | |
1110 | */ | |
1111 | bio = throtl_pop_queued(&sq->queued[rw], &tg_to_put); | |
73f0d49a | 1112 | sq->nr_queued[rw]--; |
e43473b7 VG |
1113 | |
1114 | throtl_charge_bio(tg, bio); | |
6bc9c2b4 TH |
1115 | |
1116 | /* | |
1117 | * If our parent is another tg, we just need to transfer @bio to | |
1118 | * the parent using throtl_add_bio_tg(). If our parent is | |
1119 | * @td->service_queue, @bio is ready to be issued. Put it on its | |
1120 | * bio_lists[] and decrease total number queued. The caller is | |
1121 | * responsible for issuing these bios. | |
1122 | */ | |
1123 | if (parent_tg) { | |
c5cc2070 | 1124 | throtl_add_bio_tg(bio, &tg->qnode_on_parent[rw], parent_tg); |
32ee5bc4 | 1125 | start_parent_slice_with_credit(tg, parent_tg, rw); |
6bc9c2b4 | 1126 | } else { |
c5cc2070 TH |
1127 | throtl_qnode_add_bio(bio, &tg->qnode_on_parent[rw], |
1128 | &parent_sq->queued[rw]); | |
6bc9c2b4 TH |
1129 | BUG_ON(tg->td->nr_queued[rw] <= 0); |
1130 | tg->td->nr_queued[rw]--; | |
1131 | } | |
e43473b7 | 1132 | |
0f3457f6 | 1133 | throtl_trim_slice(tg, rw); |
6bc9c2b4 | 1134 | |
c5cc2070 TH |
1135 | if (tg_to_put) |
1136 | blkg_put(tg_to_blkg(tg_to_put)); | |
e43473b7 VG |
1137 | } |
1138 | ||
77216b04 | 1139 | static int throtl_dispatch_tg(struct throtl_grp *tg) |
e43473b7 | 1140 | { |
73f0d49a | 1141 | struct throtl_service_queue *sq = &tg->service_queue; |
e43473b7 VG |
1142 | unsigned int nr_reads = 0, nr_writes = 0; |
1143 | unsigned int max_nr_reads = throtl_grp_quantum*3/4; | |
c2f6805d | 1144 | unsigned int max_nr_writes = throtl_grp_quantum - max_nr_reads; |
e43473b7 VG |
1145 | struct bio *bio; |
1146 | ||
1147 | /* Try to dispatch 75% READS and 25% WRITES */ | |
1148 | ||
c5cc2070 | 1149 | while ((bio = throtl_peek_queued(&sq->queued[READ])) && |
0f3457f6 | 1150 | tg_may_dispatch(tg, bio, NULL)) { |
e43473b7 | 1151 | |
77216b04 | 1152 | tg_dispatch_one_bio(tg, bio_data_dir(bio)); |
e43473b7 VG |
1153 | nr_reads++; |
1154 | ||
1155 | if (nr_reads >= max_nr_reads) | |
1156 | break; | |
1157 | } | |
1158 | ||
c5cc2070 | 1159 | while ((bio = throtl_peek_queued(&sq->queued[WRITE])) && |
0f3457f6 | 1160 | tg_may_dispatch(tg, bio, NULL)) { |
e43473b7 | 1161 | |
77216b04 | 1162 | tg_dispatch_one_bio(tg, bio_data_dir(bio)); |
e43473b7 VG |
1163 | nr_writes++; |
1164 | ||
1165 | if (nr_writes >= max_nr_writes) | |
1166 | break; | |
1167 | } | |
1168 | ||
1169 | return nr_reads + nr_writes; | |
1170 | } | |
1171 | ||
651930bc | 1172 | static int throtl_select_dispatch(struct throtl_service_queue *parent_sq) |
e43473b7 VG |
1173 | { |
1174 | unsigned int nr_disp = 0; | |
e43473b7 VG |
1175 | |
1176 | while (1) { | |
73f0d49a TH |
1177 | struct throtl_grp *tg = throtl_rb_first(parent_sq); |
1178 | struct throtl_service_queue *sq = &tg->service_queue; | |
e43473b7 VG |
1179 | |
1180 | if (!tg) | |
1181 | break; | |
1182 | ||
1183 | if (time_before(jiffies, tg->disptime)) | |
1184 | break; | |
1185 | ||
77216b04 | 1186 | throtl_dequeue_tg(tg); |
e43473b7 | 1187 | |
77216b04 | 1188 | nr_disp += throtl_dispatch_tg(tg); |
e43473b7 | 1189 | |
73f0d49a | 1190 | if (sq->nr_queued[0] || sq->nr_queued[1]) |
77216b04 | 1191 | tg_update_disptime(tg); |
e43473b7 VG |
1192 | |
1193 | if (nr_disp >= throtl_quantum) | |
1194 | break; | |
1195 | } | |
1196 | ||
1197 | return nr_disp; | |
1198 | } | |
1199 | ||
c79892c5 SL |
1200 | static bool throtl_can_upgrade(struct throtl_data *td, |
1201 | struct throtl_grp *this_tg); | |
6e1a5704 TH |
1202 | /** |
1203 | * throtl_pending_timer_fn - timer function for service_queue->pending_timer | |
1204 | * @arg: the throtl_service_queue being serviced | |
1205 | * | |
1206 | * This timer is armed when a child throtl_grp with active bio's become | |
1207 | * pending and queued on the service_queue's pending_tree and expires when | |
1208 | * the first child throtl_grp should be dispatched. This function | |
2e48a530 TH |
1209 | * dispatches bio's from the children throtl_grps to the parent |
1210 | * service_queue. | |
1211 | * | |
1212 | * If the parent's parent is another throtl_grp, dispatching is propagated | |
1213 | * by either arming its pending_timer or repeating dispatch directly. If | |
1214 | * the top-level service_tree is reached, throtl_data->dispatch_work is | |
1215 | * kicked so that the ready bio's are issued. | |
6e1a5704 | 1216 | */ |
69df0ab0 TH |
1217 | static void throtl_pending_timer_fn(unsigned long arg) |
1218 | { | |
1219 | struct throtl_service_queue *sq = (void *)arg; | |
2e48a530 | 1220 | struct throtl_grp *tg = sq_to_tg(sq); |
69df0ab0 | 1221 | struct throtl_data *td = sq_to_td(sq); |
cb76199c | 1222 | struct request_queue *q = td->queue; |
2e48a530 TH |
1223 | struct throtl_service_queue *parent_sq; |
1224 | bool dispatched; | |
6e1a5704 | 1225 | int ret; |
e43473b7 VG |
1226 | |
1227 | spin_lock_irq(q->queue_lock); | |
c79892c5 SL |
1228 | if (throtl_can_upgrade(td, NULL)) |
1229 | throtl_upgrade_state(td); | |
1230 | ||
2e48a530 TH |
1231 | again: |
1232 | parent_sq = sq->parent_sq; | |
1233 | dispatched = false; | |
e43473b7 | 1234 | |
7f52f98c TH |
1235 | while (true) { |
1236 | throtl_log(sq, "dispatch nr_queued=%u read=%u write=%u", | |
2e48a530 TH |
1237 | sq->nr_queued[READ] + sq->nr_queued[WRITE], |
1238 | sq->nr_queued[READ], sq->nr_queued[WRITE]); | |
7f52f98c TH |
1239 | |
1240 | ret = throtl_select_dispatch(sq); | |
1241 | if (ret) { | |
7f52f98c TH |
1242 | throtl_log(sq, "bios disp=%u", ret); |
1243 | dispatched = true; | |
1244 | } | |
e43473b7 | 1245 | |
7f52f98c TH |
1246 | if (throtl_schedule_next_dispatch(sq, false)) |
1247 | break; | |
e43473b7 | 1248 | |
7f52f98c TH |
1249 | /* this dispatch windows is still open, relax and repeat */ |
1250 | spin_unlock_irq(q->queue_lock); | |
1251 | cpu_relax(); | |
1252 | spin_lock_irq(q->queue_lock); | |
651930bc | 1253 | } |
e43473b7 | 1254 | |
2e48a530 TH |
1255 | if (!dispatched) |
1256 | goto out_unlock; | |
6e1a5704 | 1257 | |
2e48a530 TH |
1258 | if (parent_sq) { |
1259 | /* @parent_sq is another throl_grp, propagate dispatch */ | |
1260 | if (tg->flags & THROTL_TG_WAS_EMPTY) { | |
1261 | tg_update_disptime(tg); | |
1262 | if (!throtl_schedule_next_dispatch(parent_sq, false)) { | |
1263 | /* window is already open, repeat dispatching */ | |
1264 | sq = parent_sq; | |
1265 | tg = sq_to_tg(sq); | |
1266 | goto again; | |
1267 | } | |
1268 | } | |
1269 | } else { | |
1270 | /* reached the top-level, queue issueing */ | |
1271 | queue_work(kthrotld_workqueue, &td->dispatch_work); | |
1272 | } | |
1273 | out_unlock: | |
e43473b7 | 1274 | spin_unlock_irq(q->queue_lock); |
6e1a5704 | 1275 | } |
e43473b7 | 1276 | |
6e1a5704 TH |
1277 | /** |
1278 | * blk_throtl_dispatch_work_fn - work function for throtl_data->dispatch_work | |
1279 | * @work: work item being executed | |
1280 | * | |
1281 | * This function is queued for execution when bio's reach the bio_lists[] | |
1282 | * of throtl_data->service_queue. Those bio's are ready and issued by this | |
1283 | * function. | |
1284 | */ | |
8876e140 | 1285 | static void blk_throtl_dispatch_work_fn(struct work_struct *work) |
6e1a5704 TH |
1286 | { |
1287 | struct throtl_data *td = container_of(work, struct throtl_data, | |
1288 | dispatch_work); | |
1289 | struct throtl_service_queue *td_sq = &td->service_queue; | |
1290 | struct request_queue *q = td->queue; | |
1291 | struct bio_list bio_list_on_stack; | |
1292 | struct bio *bio; | |
1293 | struct blk_plug plug; | |
1294 | int rw; | |
1295 | ||
1296 | bio_list_init(&bio_list_on_stack); | |
1297 | ||
1298 | spin_lock_irq(q->queue_lock); | |
c5cc2070 TH |
1299 | for (rw = READ; rw <= WRITE; rw++) |
1300 | while ((bio = throtl_pop_queued(&td_sq->queued[rw], NULL))) | |
1301 | bio_list_add(&bio_list_on_stack, bio); | |
6e1a5704 TH |
1302 | spin_unlock_irq(q->queue_lock); |
1303 | ||
1304 | if (!bio_list_empty(&bio_list_on_stack)) { | |
69d60eb9 | 1305 | blk_start_plug(&plug); |
e43473b7 VG |
1306 | while((bio = bio_list_pop(&bio_list_on_stack))) |
1307 | generic_make_request(bio); | |
69d60eb9 | 1308 | blk_finish_plug(&plug); |
e43473b7 | 1309 | } |
e43473b7 VG |
1310 | } |
1311 | ||
f95a04af TH |
1312 | static u64 tg_prfill_conf_u64(struct seq_file *sf, struct blkg_policy_data *pd, |
1313 | int off) | |
60c2bc2d | 1314 | { |
f95a04af TH |
1315 | struct throtl_grp *tg = pd_to_tg(pd); |
1316 | u64 v = *(u64 *)((void *)tg + off); | |
60c2bc2d | 1317 | |
2ab5492d | 1318 | if (v == U64_MAX) |
60c2bc2d | 1319 | return 0; |
f95a04af | 1320 | return __blkg_prfill_u64(sf, pd, v); |
60c2bc2d TH |
1321 | } |
1322 | ||
f95a04af TH |
1323 | static u64 tg_prfill_conf_uint(struct seq_file *sf, struct blkg_policy_data *pd, |
1324 | int off) | |
e43473b7 | 1325 | { |
f95a04af TH |
1326 | struct throtl_grp *tg = pd_to_tg(pd); |
1327 | unsigned int v = *(unsigned int *)((void *)tg + off); | |
fe071437 | 1328 | |
2ab5492d | 1329 | if (v == UINT_MAX) |
af133ceb | 1330 | return 0; |
f95a04af | 1331 | return __blkg_prfill_u64(sf, pd, v); |
e43473b7 VG |
1332 | } |
1333 | ||
2da8ca82 | 1334 | static int tg_print_conf_u64(struct seq_file *sf, void *v) |
8e89d13f | 1335 | { |
2da8ca82 TH |
1336 | blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), tg_prfill_conf_u64, |
1337 | &blkcg_policy_throtl, seq_cft(sf)->private, false); | |
af133ceb | 1338 | return 0; |
8e89d13f VG |
1339 | } |
1340 | ||
2da8ca82 | 1341 | static int tg_print_conf_uint(struct seq_file *sf, void *v) |
8e89d13f | 1342 | { |
2da8ca82 TH |
1343 | blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), tg_prfill_conf_uint, |
1344 | &blkcg_policy_throtl, seq_cft(sf)->private, false); | |
af133ceb | 1345 | return 0; |
60c2bc2d TH |
1346 | } |
1347 | ||
69948b07 | 1348 | static void tg_conf_updated(struct throtl_grp *tg) |
60c2bc2d | 1349 | { |
69948b07 | 1350 | struct throtl_service_queue *sq = &tg->service_queue; |
492eb21b | 1351 | struct cgroup_subsys_state *pos_css; |
69948b07 | 1352 | struct blkcg_gq *blkg; |
af133ceb | 1353 | |
fda6f272 TH |
1354 | throtl_log(&tg->service_queue, |
1355 | "limit change rbps=%llu wbps=%llu riops=%u wiops=%u", | |
9f626e37 SL |
1356 | tg_bps_limit(tg, READ), tg_bps_limit(tg, WRITE), |
1357 | tg_iops_limit(tg, READ), tg_iops_limit(tg, WRITE)); | |
632b4493 | 1358 | |
693e751e TH |
1359 | /* |
1360 | * Update has_rules[] flags for the updated tg's subtree. A tg is | |
1361 | * considered to have rules if either the tg itself or any of its | |
1362 | * ancestors has rules. This identifies groups without any | |
1363 | * restrictions in the whole hierarchy and allows them to bypass | |
1364 | * blk-throttle. | |
1365 | */ | |
69948b07 | 1366 | blkg_for_each_descendant_pre(blkg, pos_css, tg_to_blkg(tg)) |
693e751e TH |
1367 | tg_update_has_rules(blkg_to_tg(blkg)); |
1368 | ||
632b4493 TH |
1369 | /* |
1370 | * We're already holding queue_lock and know @tg is valid. Let's | |
1371 | * apply the new config directly. | |
1372 | * | |
1373 | * Restart the slices for both READ and WRITES. It might happen | |
1374 | * that a group's limit are dropped suddenly and we don't want to | |
1375 | * account recently dispatched IO with new low rate. | |
1376 | */ | |
0f3457f6 TH |
1377 | throtl_start_new_slice(tg, 0); |
1378 | throtl_start_new_slice(tg, 1); | |
632b4493 | 1379 | |
5b2c16aa | 1380 | if (tg->flags & THROTL_TG_PENDING) { |
77216b04 | 1381 | tg_update_disptime(tg); |
7f52f98c | 1382 | throtl_schedule_next_dispatch(sq->parent_sq, true); |
632b4493 | 1383 | } |
69948b07 TH |
1384 | } |
1385 | ||
1386 | static ssize_t tg_set_conf(struct kernfs_open_file *of, | |
1387 | char *buf, size_t nbytes, loff_t off, bool is_u64) | |
1388 | { | |
1389 | struct blkcg *blkcg = css_to_blkcg(of_css(of)); | |
1390 | struct blkg_conf_ctx ctx; | |
1391 | struct throtl_grp *tg; | |
1392 | int ret; | |
1393 | u64 v; | |
1394 | ||
1395 | ret = blkg_conf_prep(blkcg, &blkcg_policy_throtl, buf, &ctx); | |
1396 | if (ret) | |
1397 | return ret; | |
1398 | ||
1399 | ret = -EINVAL; | |
1400 | if (sscanf(ctx.body, "%llu", &v) != 1) | |
1401 | goto out_finish; | |
1402 | if (!v) | |
2ab5492d | 1403 | v = U64_MAX; |
69948b07 TH |
1404 | |
1405 | tg = blkg_to_tg(ctx.blkg); | |
1406 | ||
1407 | if (is_u64) | |
1408 | *(u64 *)((void *)tg + of_cft(of)->private) = v; | |
1409 | else | |
1410 | *(unsigned int *)((void *)tg + of_cft(of)->private) = v; | |
60c2bc2d | 1411 | |
69948b07 | 1412 | tg_conf_updated(tg); |
36aa9e5f TH |
1413 | ret = 0; |
1414 | out_finish: | |
60c2bc2d | 1415 | blkg_conf_finish(&ctx); |
36aa9e5f | 1416 | return ret ?: nbytes; |
8e89d13f VG |
1417 | } |
1418 | ||
451af504 TH |
1419 | static ssize_t tg_set_conf_u64(struct kernfs_open_file *of, |
1420 | char *buf, size_t nbytes, loff_t off) | |
60c2bc2d | 1421 | { |
451af504 | 1422 | return tg_set_conf(of, buf, nbytes, off, true); |
60c2bc2d TH |
1423 | } |
1424 | ||
451af504 TH |
1425 | static ssize_t tg_set_conf_uint(struct kernfs_open_file *of, |
1426 | char *buf, size_t nbytes, loff_t off) | |
60c2bc2d | 1427 | { |
451af504 | 1428 | return tg_set_conf(of, buf, nbytes, off, false); |
60c2bc2d TH |
1429 | } |
1430 | ||
880f50e2 | 1431 | static struct cftype throtl_legacy_files[] = { |
60c2bc2d TH |
1432 | { |
1433 | .name = "throttle.read_bps_device", | |
9f626e37 | 1434 | .private = offsetof(struct throtl_grp, bps[READ][LIMIT_MAX]), |
2da8ca82 | 1435 | .seq_show = tg_print_conf_u64, |
451af504 | 1436 | .write = tg_set_conf_u64, |
60c2bc2d TH |
1437 | }, |
1438 | { | |
1439 | .name = "throttle.write_bps_device", | |
9f626e37 | 1440 | .private = offsetof(struct throtl_grp, bps[WRITE][LIMIT_MAX]), |
2da8ca82 | 1441 | .seq_show = tg_print_conf_u64, |
451af504 | 1442 | .write = tg_set_conf_u64, |
60c2bc2d TH |
1443 | }, |
1444 | { | |
1445 | .name = "throttle.read_iops_device", | |
9f626e37 | 1446 | .private = offsetof(struct throtl_grp, iops[READ][LIMIT_MAX]), |
2da8ca82 | 1447 | .seq_show = tg_print_conf_uint, |
451af504 | 1448 | .write = tg_set_conf_uint, |
60c2bc2d TH |
1449 | }, |
1450 | { | |
1451 | .name = "throttle.write_iops_device", | |
9f626e37 | 1452 | .private = offsetof(struct throtl_grp, iops[WRITE][LIMIT_MAX]), |
2da8ca82 | 1453 | .seq_show = tg_print_conf_uint, |
451af504 | 1454 | .write = tg_set_conf_uint, |
60c2bc2d TH |
1455 | }, |
1456 | { | |
1457 | .name = "throttle.io_service_bytes", | |
77ea7338 TH |
1458 | .private = (unsigned long)&blkcg_policy_throtl, |
1459 | .seq_show = blkg_print_stat_bytes, | |
60c2bc2d TH |
1460 | }, |
1461 | { | |
1462 | .name = "throttle.io_serviced", | |
77ea7338 TH |
1463 | .private = (unsigned long)&blkcg_policy_throtl, |
1464 | .seq_show = blkg_print_stat_ios, | |
60c2bc2d TH |
1465 | }, |
1466 | { } /* terminate */ | |
1467 | }; | |
1468 | ||
cd5ab1b0 | 1469 | static u64 tg_prfill_limit(struct seq_file *sf, struct blkg_policy_data *pd, |
2ee867dc TH |
1470 | int off) |
1471 | { | |
1472 | struct throtl_grp *tg = pd_to_tg(pd); | |
1473 | const char *dname = blkg_dev_name(pd->blkg); | |
1474 | char bufs[4][21] = { "max", "max", "max", "max" }; | |
cd5ab1b0 SL |
1475 | u64 bps_dft; |
1476 | unsigned int iops_dft; | |
ada75b6e | 1477 | char idle_time[26] = ""; |
ec80991d | 1478 | char latency_time[26] = ""; |
2ee867dc TH |
1479 | |
1480 | if (!dname) | |
1481 | return 0; | |
9f626e37 | 1482 | |
cd5ab1b0 SL |
1483 | if (off == LIMIT_LOW) { |
1484 | bps_dft = 0; | |
1485 | iops_dft = 0; | |
1486 | } else { | |
1487 | bps_dft = U64_MAX; | |
1488 | iops_dft = UINT_MAX; | |
1489 | } | |
1490 | ||
1491 | if (tg->bps_conf[READ][off] == bps_dft && | |
1492 | tg->bps_conf[WRITE][off] == bps_dft && | |
1493 | tg->iops_conf[READ][off] == iops_dft && | |
ada75b6e | 1494 | tg->iops_conf[WRITE][off] == iops_dft && |
ec80991d SL |
1495 | (off != LIMIT_LOW || |
1496 | (tg->idletime_threshold == tg->td->dft_idletime_threshold && | |
1497 | tg->latency_target == DFL_LATENCY_TARGET))) | |
2ee867dc TH |
1498 | return 0; |
1499 | ||
cd5ab1b0 | 1500 | if (tg->bps_conf[READ][off] != bps_dft) |
9f626e37 | 1501 | snprintf(bufs[0], sizeof(bufs[0]), "%llu", |
cd5ab1b0 SL |
1502 | tg->bps_conf[READ][off]); |
1503 | if (tg->bps_conf[WRITE][off] != bps_dft) | |
9f626e37 | 1504 | snprintf(bufs[1], sizeof(bufs[1]), "%llu", |
cd5ab1b0 SL |
1505 | tg->bps_conf[WRITE][off]); |
1506 | if (tg->iops_conf[READ][off] != iops_dft) | |
9f626e37 | 1507 | snprintf(bufs[2], sizeof(bufs[2]), "%u", |
cd5ab1b0 SL |
1508 | tg->iops_conf[READ][off]); |
1509 | if (tg->iops_conf[WRITE][off] != iops_dft) | |
9f626e37 | 1510 | snprintf(bufs[3], sizeof(bufs[3]), "%u", |
cd5ab1b0 | 1511 | tg->iops_conf[WRITE][off]); |
ada75b6e SL |
1512 | if (off == LIMIT_LOW) { |
1513 | if (tg->idletime_threshold == ULONG_MAX) | |
1514 | strcpy(idle_time, " idle=max"); | |
1515 | else | |
1516 | snprintf(idle_time, sizeof(idle_time), " idle=%lu", | |
1517 | tg->idletime_threshold); | |
ec80991d SL |
1518 | |
1519 | if (tg->latency_target == ULONG_MAX) | |
1520 | strcpy(latency_time, " latency=max"); | |
1521 | else | |
1522 | snprintf(latency_time, sizeof(latency_time), | |
1523 | " latency=%lu", tg->latency_target); | |
ada75b6e | 1524 | } |
2ee867dc | 1525 | |
ec80991d SL |
1526 | seq_printf(sf, "%s rbps=%s wbps=%s riops=%s wiops=%s%s%s\n", |
1527 | dname, bufs[0], bufs[1], bufs[2], bufs[3], idle_time, | |
1528 | latency_time); | |
2ee867dc TH |
1529 | return 0; |
1530 | } | |
1531 | ||
cd5ab1b0 | 1532 | static int tg_print_limit(struct seq_file *sf, void *v) |
2ee867dc | 1533 | { |
cd5ab1b0 | 1534 | blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), tg_prfill_limit, |
2ee867dc TH |
1535 | &blkcg_policy_throtl, seq_cft(sf)->private, false); |
1536 | return 0; | |
1537 | } | |
1538 | ||
cd5ab1b0 | 1539 | static ssize_t tg_set_limit(struct kernfs_open_file *of, |
2ee867dc TH |
1540 | char *buf, size_t nbytes, loff_t off) |
1541 | { | |
1542 | struct blkcg *blkcg = css_to_blkcg(of_css(of)); | |
1543 | struct blkg_conf_ctx ctx; | |
1544 | struct throtl_grp *tg; | |
1545 | u64 v[4]; | |
ada75b6e | 1546 | unsigned long idle_time; |
ec80991d | 1547 | unsigned long latency_time; |
2ee867dc | 1548 | int ret; |
cd5ab1b0 | 1549 | int index = of_cft(of)->private; |
2ee867dc TH |
1550 | |
1551 | ret = blkg_conf_prep(blkcg, &blkcg_policy_throtl, buf, &ctx); | |
1552 | if (ret) | |
1553 | return ret; | |
1554 | ||
1555 | tg = blkg_to_tg(ctx.blkg); | |
1556 | ||
cd5ab1b0 SL |
1557 | v[0] = tg->bps_conf[READ][index]; |
1558 | v[1] = tg->bps_conf[WRITE][index]; | |
1559 | v[2] = tg->iops_conf[READ][index]; | |
1560 | v[3] = tg->iops_conf[WRITE][index]; | |
2ee867dc | 1561 | |
ada75b6e | 1562 | idle_time = tg->idletime_threshold; |
ec80991d | 1563 | latency_time = tg->latency_target; |
2ee867dc TH |
1564 | while (true) { |
1565 | char tok[27]; /* wiops=18446744073709551616 */ | |
1566 | char *p; | |
2ab5492d | 1567 | u64 val = U64_MAX; |
2ee867dc TH |
1568 | int len; |
1569 | ||
1570 | if (sscanf(ctx.body, "%26s%n", tok, &len) != 1) | |
1571 | break; | |
1572 | if (tok[0] == '\0') | |
1573 | break; | |
1574 | ctx.body += len; | |
1575 | ||
1576 | ret = -EINVAL; | |
1577 | p = tok; | |
1578 | strsep(&p, "="); | |
1579 | if (!p || (sscanf(p, "%llu", &val) != 1 && strcmp(p, "max"))) | |
1580 | goto out_finish; | |
1581 | ||
1582 | ret = -ERANGE; | |
1583 | if (!val) | |
1584 | goto out_finish; | |
1585 | ||
1586 | ret = -EINVAL; | |
1587 | if (!strcmp(tok, "rbps")) | |
1588 | v[0] = val; | |
1589 | else if (!strcmp(tok, "wbps")) | |
1590 | v[1] = val; | |
1591 | else if (!strcmp(tok, "riops")) | |
1592 | v[2] = min_t(u64, val, UINT_MAX); | |
1593 | else if (!strcmp(tok, "wiops")) | |
1594 | v[3] = min_t(u64, val, UINT_MAX); | |
ada75b6e SL |
1595 | else if (off == LIMIT_LOW && !strcmp(tok, "idle")) |
1596 | idle_time = val; | |
ec80991d SL |
1597 | else if (off == LIMIT_LOW && !strcmp(tok, "latency")) |
1598 | latency_time = val; | |
2ee867dc TH |
1599 | else |
1600 | goto out_finish; | |
1601 | } | |
1602 | ||
cd5ab1b0 SL |
1603 | tg->bps_conf[READ][index] = v[0]; |
1604 | tg->bps_conf[WRITE][index] = v[1]; | |
1605 | tg->iops_conf[READ][index] = v[2]; | |
1606 | tg->iops_conf[WRITE][index] = v[3]; | |
2ee867dc | 1607 | |
cd5ab1b0 SL |
1608 | if (index == LIMIT_MAX) { |
1609 | tg->bps[READ][index] = v[0]; | |
1610 | tg->bps[WRITE][index] = v[1]; | |
1611 | tg->iops[READ][index] = v[2]; | |
1612 | tg->iops[WRITE][index] = v[3]; | |
1613 | } | |
1614 | tg->bps[READ][LIMIT_LOW] = min(tg->bps_conf[READ][LIMIT_LOW], | |
1615 | tg->bps_conf[READ][LIMIT_MAX]); | |
1616 | tg->bps[WRITE][LIMIT_LOW] = min(tg->bps_conf[WRITE][LIMIT_LOW], | |
1617 | tg->bps_conf[WRITE][LIMIT_MAX]); | |
1618 | tg->iops[READ][LIMIT_LOW] = min(tg->iops_conf[READ][LIMIT_LOW], | |
1619 | tg->iops_conf[READ][LIMIT_MAX]); | |
1620 | tg->iops[WRITE][LIMIT_LOW] = min(tg->iops_conf[WRITE][LIMIT_LOW], | |
1621 | tg->iops_conf[WRITE][LIMIT_MAX]); | |
1622 | ||
1623 | if (index == LIMIT_LOW) { | |
1624 | blk_throtl_update_limit_valid(tg->td); | |
1625 | if (tg->td->limit_valid[LIMIT_LOW]) | |
1626 | tg->td->limit_index = LIMIT_LOW; | |
ada75b6e SL |
1627 | tg->idletime_threshold = (idle_time == ULONG_MAX) ? |
1628 | ULONG_MAX : idle_time; | |
ec80991d SL |
1629 | tg->latency_target = (latency_time == ULONG_MAX) ? |
1630 | ULONG_MAX : latency_time; | |
cd5ab1b0 | 1631 | } |
2ee867dc TH |
1632 | tg_conf_updated(tg); |
1633 | ret = 0; | |
1634 | out_finish: | |
1635 | blkg_conf_finish(&ctx); | |
1636 | return ret ?: nbytes; | |
1637 | } | |
1638 | ||
1639 | static struct cftype throtl_files[] = { | |
cd5ab1b0 SL |
1640 | #ifdef CONFIG_BLK_DEV_THROTTLING_LOW |
1641 | { | |
1642 | .name = "low", | |
1643 | .flags = CFTYPE_NOT_ON_ROOT, | |
1644 | .seq_show = tg_print_limit, | |
1645 | .write = tg_set_limit, | |
1646 | .private = LIMIT_LOW, | |
1647 | }, | |
1648 | #endif | |
2ee867dc TH |
1649 | { |
1650 | .name = "max", | |
1651 | .flags = CFTYPE_NOT_ON_ROOT, | |
cd5ab1b0 SL |
1652 | .seq_show = tg_print_limit, |
1653 | .write = tg_set_limit, | |
1654 | .private = LIMIT_MAX, | |
2ee867dc TH |
1655 | }, |
1656 | { } /* terminate */ | |
1657 | }; | |
1658 | ||
da527770 | 1659 | static void throtl_shutdown_wq(struct request_queue *q) |
e43473b7 VG |
1660 | { |
1661 | struct throtl_data *td = q->td; | |
1662 | ||
69df0ab0 | 1663 | cancel_work_sync(&td->dispatch_work); |
e43473b7 VG |
1664 | } |
1665 | ||
3c798398 | 1666 | static struct blkcg_policy blkcg_policy_throtl = { |
2ee867dc | 1667 | .dfl_cftypes = throtl_files, |
880f50e2 | 1668 | .legacy_cftypes = throtl_legacy_files, |
f9fcc2d3 | 1669 | |
001bea73 | 1670 | .pd_alloc_fn = throtl_pd_alloc, |
f9fcc2d3 | 1671 | .pd_init_fn = throtl_pd_init, |
693e751e | 1672 | .pd_online_fn = throtl_pd_online, |
cd5ab1b0 | 1673 | .pd_offline_fn = throtl_pd_offline, |
001bea73 | 1674 | .pd_free_fn = throtl_pd_free, |
e43473b7 VG |
1675 | }; |
1676 | ||
3f0abd80 SL |
1677 | static unsigned long __tg_last_low_overflow_time(struct throtl_grp *tg) |
1678 | { | |
1679 | unsigned long rtime = jiffies, wtime = jiffies; | |
1680 | ||
1681 | if (tg->bps[READ][LIMIT_LOW] || tg->iops[READ][LIMIT_LOW]) | |
1682 | rtime = tg->last_low_overflow_time[READ]; | |
1683 | if (tg->bps[WRITE][LIMIT_LOW] || tg->iops[WRITE][LIMIT_LOW]) | |
1684 | wtime = tg->last_low_overflow_time[WRITE]; | |
1685 | return min(rtime, wtime); | |
1686 | } | |
1687 | ||
1688 | /* tg should not be an intermediate node */ | |
1689 | static unsigned long tg_last_low_overflow_time(struct throtl_grp *tg) | |
1690 | { | |
1691 | struct throtl_service_queue *parent_sq; | |
1692 | struct throtl_grp *parent = tg; | |
1693 | unsigned long ret = __tg_last_low_overflow_time(tg); | |
1694 | ||
1695 | while (true) { | |
1696 | parent_sq = parent->service_queue.parent_sq; | |
1697 | parent = sq_to_tg(parent_sq); | |
1698 | if (!parent) | |
1699 | break; | |
1700 | ||
1701 | /* | |
1702 | * The parent doesn't have low limit, it always reaches low | |
1703 | * limit. Its overflow time is useless for children | |
1704 | */ | |
1705 | if (!parent->bps[READ][LIMIT_LOW] && | |
1706 | !parent->iops[READ][LIMIT_LOW] && | |
1707 | !parent->bps[WRITE][LIMIT_LOW] && | |
1708 | !parent->iops[WRITE][LIMIT_LOW]) | |
1709 | continue; | |
1710 | if (time_after(__tg_last_low_overflow_time(parent), ret)) | |
1711 | ret = __tg_last_low_overflow_time(parent); | |
1712 | } | |
1713 | return ret; | |
1714 | } | |
1715 | ||
9e234eea SL |
1716 | static bool throtl_tg_is_idle(struct throtl_grp *tg) |
1717 | { | |
1718 | /* | |
1719 | * cgroup is idle if: | |
1720 | * - single idle is too long, longer than a fixed value (in case user | |
1721 | * configure a too big threshold) or 4 times of slice | |
1722 | * - average think time is more than threshold | |
1723 | */ | |
1724 | unsigned long time = jiffies_to_usecs(4 * tg->td->throtl_slice); | |
1725 | ||
1726 | time = min_t(unsigned long, MAX_IDLE_TIME, time); | |
1727 | return (ktime_get_ns() >> 10) - tg->last_finish_time > time || | |
1728 | tg->avg_idletime > tg->idletime_threshold; | |
1729 | } | |
1730 | ||
c79892c5 SL |
1731 | static bool throtl_tg_can_upgrade(struct throtl_grp *tg) |
1732 | { | |
1733 | struct throtl_service_queue *sq = &tg->service_queue; | |
1734 | bool read_limit, write_limit; | |
1735 | ||
1736 | /* | |
1737 | * if cgroup reaches low limit (if low limit is 0, the cgroup always | |
1738 | * reaches), it's ok to upgrade to next limit | |
1739 | */ | |
1740 | read_limit = tg->bps[READ][LIMIT_LOW] || tg->iops[READ][LIMIT_LOW]; | |
1741 | write_limit = tg->bps[WRITE][LIMIT_LOW] || tg->iops[WRITE][LIMIT_LOW]; | |
1742 | if (!read_limit && !write_limit) | |
1743 | return true; | |
1744 | if (read_limit && sq->nr_queued[READ] && | |
1745 | (!write_limit || sq->nr_queued[WRITE])) | |
1746 | return true; | |
1747 | if (write_limit && sq->nr_queued[WRITE] && | |
1748 | (!read_limit || sq->nr_queued[READ])) | |
1749 | return true; | |
aec24246 SL |
1750 | |
1751 | if (time_after_eq(jiffies, | |
fa6fb5aa SL |
1752 | tg_last_low_overflow_time(tg) + tg->td->throtl_slice) && |
1753 | throtl_tg_is_idle(tg)) | |
aec24246 | 1754 | return true; |
c79892c5 SL |
1755 | return false; |
1756 | } | |
1757 | ||
1758 | static bool throtl_hierarchy_can_upgrade(struct throtl_grp *tg) | |
1759 | { | |
1760 | while (true) { | |
1761 | if (throtl_tg_can_upgrade(tg)) | |
1762 | return true; | |
1763 | tg = sq_to_tg(tg->service_queue.parent_sq); | |
1764 | if (!tg || !tg_to_blkg(tg)->parent) | |
1765 | return false; | |
1766 | } | |
1767 | return false; | |
1768 | } | |
1769 | ||
1770 | static bool throtl_can_upgrade(struct throtl_data *td, | |
1771 | struct throtl_grp *this_tg) | |
1772 | { | |
1773 | struct cgroup_subsys_state *pos_css; | |
1774 | struct blkcg_gq *blkg; | |
1775 | ||
1776 | if (td->limit_index != LIMIT_LOW) | |
1777 | return false; | |
1778 | ||
297e3d85 | 1779 | if (time_before(jiffies, td->low_downgrade_time + td->throtl_slice)) |
3f0abd80 SL |
1780 | return false; |
1781 | ||
c79892c5 SL |
1782 | rcu_read_lock(); |
1783 | blkg_for_each_descendant_post(blkg, pos_css, td->queue->root_blkg) { | |
1784 | struct throtl_grp *tg = blkg_to_tg(blkg); | |
1785 | ||
1786 | if (tg == this_tg) | |
1787 | continue; | |
1788 | if (!list_empty(&tg_to_blkg(tg)->blkcg->css.children)) | |
1789 | continue; | |
1790 | if (!throtl_hierarchy_can_upgrade(tg)) { | |
1791 | rcu_read_unlock(); | |
1792 | return false; | |
1793 | } | |
1794 | } | |
1795 | rcu_read_unlock(); | |
1796 | return true; | |
1797 | } | |
1798 | ||
fa6fb5aa SL |
1799 | static void throtl_upgrade_check(struct throtl_grp *tg) |
1800 | { | |
1801 | unsigned long now = jiffies; | |
1802 | ||
1803 | if (tg->td->limit_index != LIMIT_LOW) | |
1804 | return; | |
1805 | ||
1806 | if (time_after(tg->last_check_time + tg->td->throtl_slice, now)) | |
1807 | return; | |
1808 | ||
1809 | tg->last_check_time = now; | |
1810 | ||
1811 | if (!time_after_eq(now, | |
1812 | __tg_last_low_overflow_time(tg) + tg->td->throtl_slice)) | |
1813 | return; | |
1814 | ||
1815 | if (throtl_can_upgrade(tg->td, NULL)) | |
1816 | throtl_upgrade_state(tg->td); | |
1817 | } | |
1818 | ||
c79892c5 SL |
1819 | static void throtl_upgrade_state(struct throtl_data *td) |
1820 | { | |
1821 | struct cgroup_subsys_state *pos_css; | |
1822 | struct blkcg_gq *blkg; | |
1823 | ||
1824 | td->limit_index = LIMIT_MAX; | |
3f0abd80 | 1825 | td->low_upgrade_time = jiffies; |
7394e31f | 1826 | td->scale = 0; |
c79892c5 SL |
1827 | rcu_read_lock(); |
1828 | blkg_for_each_descendant_post(blkg, pos_css, td->queue->root_blkg) { | |
1829 | struct throtl_grp *tg = blkg_to_tg(blkg); | |
1830 | struct throtl_service_queue *sq = &tg->service_queue; | |
1831 | ||
1832 | tg->disptime = jiffies - 1; | |
1833 | throtl_select_dispatch(sq); | |
1834 | throtl_schedule_next_dispatch(sq, false); | |
1835 | } | |
1836 | rcu_read_unlock(); | |
1837 | throtl_select_dispatch(&td->service_queue); | |
1838 | throtl_schedule_next_dispatch(&td->service_queue, false); | |
1839 | queue_work(kthrotld_workqueue, &td->dispatch_work); | |
1840 | } | |
1841 | ||
3f0abd80 SL |
1842 | static void throtl_downgrade_state(struct throtl_data *td, int new) |
1843 | { | |
7394e31f SL |
1844 | td->scale /= 2; |
1845 | ||
1846 | if (td->scale) { | |
1847 | td->low_upgrade_time = jiffies - td->scale * td->throtl_slice; | |
1848 | return; | |
1849 | } | |
1850 | ||
3f0abd80 SL |
1851 | td->limit_index = new; |
1852 | td->low_downgrade_time = jiffies; | |
1853 | } | |
1854 | ||
1855 | static bool throtl_tg_can_downgrade(struct throtl_grp *tg) | |
1856 | { | |
1857 | struct throtl_data *td = tg->td; | |
1858 | unsigned long now = jiffies; | |
1859 | ||
1860 | /* | |
1861 | * If cgroup is below low limit, consider downgrade and throttle other | |
1862 | * cgroups | |
1863 | */ | |
297e3d85 SL |
1864 | if (time_after_eq(now, td->low_upgrade_time + td->throtl_slice) && |
1865 | time_after_eq(now, tg_last_low_overflow_time(tg) + | |
fa6fb5aa SL |
1866 | td->throtl_slice) && |
1867 | (!throtl_tg_is_idle(tg) || | |
1868 | !list_empty(&tg_to_blkg(tg)->blkcg->css.children))) | |
3f0abd80 SL |
1869 | return true; |
1870 | return false; | |
1871 | } | |
1872 | ||
1873 | static bool throtl_hierarchy_can_downgrade(struct throtl_grp *tg) | |
1874 | { | |
1875 | while (true) { | |
1876 | if (!throtl_tg_can_downgrade(tg)) | |
1877 | return false; | |
1878 | tg = sq_to_tg(tg->service_queue.parent_sq); | |
1879 | if (!tg || !tg_to_blkg(tg)->parent) | |
1880 | break; | |
1881 | } | |
1882 | return true; | |
1883 | } | |
1884 | ||
1885 | static void throtl_downgrade_check(struct throtl_grp *tg) | |
1886 | { | |
1887 | uint64_t bps; | |
1888 | unsigned int iops; | |
1889 | unsigned long elapsed_time; | |
1890 | unsigned long now = jiffies; | |
1891 | ||
1892 | if (tg->td->limit_index != LIMIT_MAX || | |
1893 | !tg->td->limit_valid[LIMIT_LOW]) | |
1894 | return; | |
1895 | if (!list_empty(&tg_to_blkg(tg)->blkcg->css.children)) | |
1896 | return; | |
297e3d85 | 1897 | if (time_after(tg->last_check_time + tg->td->throtl_slice, now)) |
3f0abd80 SL |
1898 | return; |
1899 | ||
1900 | elapsed_time = now - tg->last_check_time; | |
1901 | tg->last_check_time = now; | |
1902 | ||
297e3d85 SL |
1903 | if (time_before(now, tg_last_low_overflow_time(tg) + |
1904 | tg->td->throtl_slice)) | |
3f0abd80 SL |
1905 | return; |
1906 | ||
1907 | if (tg->bps[READ][LIMIT_LOW]) { | |
1908 | bps = tg->last_bytes_disp[READ] * HZ; | |
1909 | do_div(bps, elapsed_time); | |
1910 | if (bps >= tg->bps[READ][LIMIT_LOW]) | |
1911 | tg->last_low_overflow_time[READ] = now; | |
1912 | } | |
1913 | ||
1914 | if (tg->bps[WRITE][LIMIT_LOW]) { | |
1915 | bps = tg->last_bytes_disp[WRITE] * HZ; | |
1916 | do_div(bps, elapsed_time); | |
1917 | if (bps >= tg->bps[WRITE][LIMIT_LOW]) | |
1918 | tg->last_low_overflow_time[WRITE] = now; | |
1919 | } | |
1920 | ||
1921 | if (tg->iops[READ][LIMIT_LOW]) { | |
1922 | iops = tg->last_io_disp[READ] * HZ / elapsed_time; | |
1923 | if (iops >= tg->iops[READ][LIMIT_LOW]) | |
1924 | tg->last_low_overflow_time[READ] = now; | |
1925 | } | |
1926 | ||
1927 | if (tg->iops[WRITE][LIMIT_LOW]) { | |
1928 | iops = tg->last_io_disp[WRITE] * HZ / elapsed_time; | |
1929 | if (iops >= tg->iops[WRITE][LIMIT_LOW]) | |
1930 | tg->last_low_overflow_time[WRITE] = now; | |
1931 | } | |
1932 | ||
1933 | /* | |
1934 | * If cgroup is below low limit, consider downgrade and throttle other | |
1935 | * cgroups | |
1936 | */ | |
1937 | if (throtl_hierarchy_can_downgrade(tg)) | |
1938 | throtl_downgrade_state(tg->td, LIMIT_LOW); | |
1939 | ||
1940 | tg->last_bytes_disp[READ] = 0; | |
1941 | tg->last_bytes_disp[WRITE] = 0; | |
1942 | tg->last_io_disp[READ] = 0; | |
1943 | tg->last_io_disp[WRITE] = 0; | |
1944 | } | |
1945 | ||
9e234eea SL |
1946 | static void blk_throtl_update_idletime(struct throtl_grp *tg) |
1947 | { | |
1948 | unsigned long now = ktime_get_ns() >> 10; | |
1949 | unsigned long last_finish_time = tg->last_finish_time; | |
1950 | ||
1951 | if (now <= last_finish_time || last_finish_time == 0 || | |
1952 | last_finish_time == tg->checked_last_finish_time) | |
1953 | return; | |
1954 | ||
1955 | tg->avg_idletime = (tg->avg_idletime * 7 + now - last_finish_time) >> 3; | |
1956 | tg->checked_last_finish_time = last_finish_time; | |
1957 | } | |
1958 | ||
b9147dd1 SL |
1959 | #ifdef CONFIG_BLK_DEV_THROTTLING_LOW |
1960 | static void throtl_update_latency_buckets(struct throtl_data *td) | |
1961 | { | |
1962 | struct avg_latency_bucket avg_latency[LATENCY_BUCKET_SIZE]; | |
1963 | int i, cpu; | |
1964 | unsigned long last_latency = 0; | |
1965 | unsigned long latency; | |
1966 | ||
1967 | if (!blk_queue_nonrot(td->queue)) | |
1968 | return; | |
1969 | if (time_before(jiffies, td->last_calculate_time + HZ)) | |
1970 | return; | |
1971 | td->last_calculate_time = jiffies; | |
1972 | ||
1973 | memset(avg_latency, 0, sizeof(avg_latency)); | |
1974 | for (i = 0; i < LATENCY_BUCKET_SIZE; i++) { | |
1975 | struct latency_bucket *tmp = &td->tmp_buckets[i]; | |
1976 | ||
1977 | for_each_possible_cpu(cpu) { | |
1978 | struct latency_bucket *bucket; | |
1979 | ||
1980 | /* this isn't race free, but ok in practice */ | |
1981 | bucket = per_cpu_ptr(td->latency_buckets, cpu); | |
1982 | tmp->total_latency += bucket[i].total_latency; | |
1983 | tmp->samples += bucket[i].samples; | |
1984 | bucket[i].total_latency = 0; | |
1985 | bucket[i].samples = 0; | |
1986 | } | |
1987 | ||
1988 | if (tmp->samples >= 32) { | |
1989 | int samples = tmp->samples; | |
1990 | ||
1991 | latency = tmp->total_latency; | |
1992 | ||
1993 | tmp->total_latency = 0; | |
1994 | tmp->samples = 0; | |
1995 | latency /= samples; | |
1996 | if (latency == 0) | |
1997 | continue; | |
1998 | avg_latency[i].latency = latency; | |
1999 | } | |
2000 | } | |
2001 | ||
2002 | for (i = 0; i < LATENCY_BUCKET_SIZE; i++) { | |
2003 | if (!avg_latency[i].latency) { | |
2004 | if (td->avg_buckets[i].latency < last_latency) | |
2005 | td->avg_buckets[i].latency = last_latency; | |
2006 | continue; | |
2007 | } | |
2008 | ||
2009 | if (!td->avg_buckets[i].valid) | |
2010 | latency = avg_latency[i].latency; | |
2011 | else | |
2012 | latency = (td->avg_buckets[i].latency * 7 + | |
2013 | avg_latency[i].latency) >> 3; | |
2014 | ||
2015 | td->avg_buckets[i].latency = max(latency, last_latency); | |
2016 | td->avg_buckets[i].valid = true; | |
2017 | last_latency = td->avg_buckets[i].latency; | |
2018 | } | |
2019 | } | |
2020 | #else | |
2021 | static inline void throtl_update_latency_buckets(struct throtl_data *td) | |
2022 | { | |
2023 | } | |
2024 | #endif | |
2025 | ||
ae118896 TH |
2026 | bool blk_throtl_bio(struct request_queue *q, struct blkcg_gq *blkg, |
2027 | struct bio *bio) | |
e43473b7 | 2028 | { |
c5cc2070 | 2029 | struct throtl_qnode *qn = NULL; |
ae118896 | 2030 | struct throtl_grp *tg = blkg_to_tg(blkg ?: q->root_blkg); |
73f0d49a | 2031 | struct throtl_service_queue *sq; |
0e9f4164 | 2032 | bool rw = bio_data_dir(bio); |
bc16a4f9 | 2033 | bool throttled = false; |
b9147dd1 | 2034 | struct throtl_data *td = tg->td; |
9e234eea | 2035 | int ret; |
e43473b7 | 2036 | |
ae118896 TH |
2037 | WARN_ON_ONCE(!rcu_read_lock_held()); |
2038 | ||
2a0f61e6 | 2039 | /* see throtl_charge_bio() */ |
8d2bbd4c | 2040 | if (bio_flagged(bio, BIO_THROTTLED) || !tg->has_rules[rw]) |
bc16a4f9 | 2041 | goto out; |
e43473b7 VG |
2042 | |
2043 | spin_lock_irq(q->queue_lock); | |
c9589f03 | 2044 | |
b9147dd1 SL |
2045 | throtl_update_latency_buckets(td); |
2046 | ||
c9589f03 | 2047 | if (unlikely(blk_queue_bypass(q))) |
bc16a4f9 | 2048 | goto out_unlock; |
f469a7b4 | 2049 | |
9e234eea SL |
2050 | ret = bio_associate_current(bio); |
2051 | #ifdef CONFIG_BLK_DEV_THROTTLING_LOW | |
2052 | if (ret == 0 || ret == -EBUSY) | |
2053 | bio->bi_cg_private = tg; | |
b9147dd1 | 2054 | blk_stat_set_issue(&bio->bi_issue_stat, bio_sectors(bio)); |
9e234eea SL |
2055 | #endif |
2056 | blk_throtl_update_idletime(tg); | |
2057 | ||
73f0d49a TH |
2058 | sq = &tg->service_queue; |
2059 | ||
c79892c5 | 2060 | again: |
9e660acf | 2061 | while (true) { |
3f0abd80 SL |
2062 | if (tg->last_low_overflow_time[rw] == 0) |
2063 | tg->last_low_overflow_time[rw] = jiffies; | |
2064 | throtl_downgrade_check(tg); | |
fa6fb5aa | 2065 | throtl_upgrade_check(tg); |
9e660acf TH |
2066 | /* throtl is FIFO - if bios are already queued, should queue */ |
2067 | if (sq->nr_queued[rw]) | |
2068 | break; | |
de701c74 | 2069 | |
9e660acf | 2070 | /* if above limits, break to queue */ |
c79892c5 | 2071 | if (!tg_may_dispatch(tg, bio, NULL)) { |
3f0abd80 | 2072 | tg->last_low_overflow_time[rw] = jiffies; |
b9147dd1 SL |
2073 | if (throtl_can_upgrade(td, tg)) { |
2074 | throtl_upgrade_state(td); | |
c79892c5 SL |
2075 | goto again; |
2076 | } | |
9e660acf | 2077 | break; |
c79892c5 | 2078 | } |
9e660acf TH |
2079 | |
2080 | /* within limits, let's charge and dispatch directly */ | |
e43473b7 | 2081 | throtl_charge_bio(tg, bio); |
04521db0 VG |
2082 | |
2083 | /* | |
2084 | * We need to trim slice even when bios are not being queued | |
2085 | * otherwise it might happen that a bio is not queued for | |
2086 | * a long time and slice keeps on extending and trim is not | |
2087 | * called for a long time. Now if limits are reduced suddenly | |
2088 | * we take into account all the IO dispatched so far at new | |
2089 | * low rate and * newly queued IO gets a really long dispatch | |
2090 | * time. | |
2091 | * | |
2092 | * So keep on trimming slice even if bio is not queued. | |
2093 | */ | |
0f3457f6 | 2094 | throtl_trim_slice(tg, rw); |
9e660acf TH |
2095 | |
2096 | /* | |
2097 | * @bio passed through this layer without being throttled. | |
2098 | * Climb up the ladder. If we''re already at the top, it | |
2099 | * can be executed directly. | |
2100 | */ | |
c5cc2070 | 2101 | qn = &tg->qnode_on_parent[rw]; |
9e660acf TH |
2102 | sq = sq->parent_sq; |
2103 | tg = sq_to_tg(sq); | |
2104 | if (!tg) | |
2105 | goto out_unlock; | |
e43473b7 VG |
2106 | } |
2107 | ||
9e660acf | 2108 | /* out-of-limit, queue to @tg */ |
fda6f272 TH |
2109 | throtl_log(sq, "[%c] bio. bdisp=%llu sz=%u bps=%llu iodisp=%u iops=%u queued=%d/%d", |
2110 | rw == READ ? 'R' : 'W', | |
9f626e37 SL |
2111 | tg->bytes_disp[rw], bio->bi_iter.bi_size, |
2112 | tg_bps_limit(tg, rw), | |
2113 | tg->io_disp[rw], tg_iops_limit(tg, rw), | |
fda6f272 | 2114 | sq->nr_queued[READ], sq->nr_queued[WRITE]); |
e43473b7 | 2115 | |
3f0abd80 SL |
2116 | tg->last_low_overflow_time[rw] = jiffies; |
2117 | ||
b9147dd1 | 2118 | td->nr_queued[rw]++; |
c5cc2070 | 2119 | throtl_add_bio_tg(bio, qn, tg); |
bc16a4f9 | 2120 | throttled = true; |
e43473b7 | 2121 | |
7f52f98c TH |
2122 | /* |
2123 | * Update @tg's dispatch time and force schedule dispatch if @tg | |
2124 | * was empty before @bio. The forced scheduling isn't likely to | |
2125 | * cause undue delay as @bio is likely to be dispatched directly if | |
2126 | * its @tg's disptime is not in the future. | |
2127 | */ | |
0e9f4164 | 2128 | if (tg->flags & THROTL_TG_WAS_EMPTY) { |
77216b04 | 2129 | tg_update_disptime(tg); |
7f52f98c | 2130 | throtl_schedule_next_dispatch(tg->service_queue.parent_sq, true); |
e43473b7 VG |
2131 | } |
2132 | ||
bc16a4f9 | 2133 | out_unlock: |
e43473b7 | 2134 | spin_unlock_irq(q->queue_lock); |
bc16a4f9 | 2135 | out: |
2a0f61e6 TH |
2136 | /* |
2137 | * As multiple blk-throtls may stack in the same issue path, we | |
2138 | * don't want bios to leave with the flag set. Clear the flag if | |
2139 | * being issued. | |
2140 | */ | |
2141 | if (!throttled) | |
8d2bbd4c | 2142 | bio_clear_flag(bio, BIO_THROTTLED); |
b9147dd1 SL |
2143 | |
2144 | #ifdef CONFIG_BLK_DEV_THROTTLING_LOW | |
2145 | if (throttled || !td->track_bio_latency) | |
2146 | bio->bi_issue_stat.stat |= SKIP_LATENCY; | |
2147 | #endif | |
bc16a4f9 | 2148 | return throttled; |
e43473b7 VG |
2149 | } |
2150 | ||
9e234eea | 2151 | #ifdef CONFIG_BLK_DEV_THROTTLING_LOW |
b9147dd1 SL |
2152 | static void throtl_track_latency(struct throtl_data *td, sector_t size, |
2153 | int op, unsigned long time) | |
2154 | { | |
2155 | struct latency_bucket *latency; | |
2156 | int index; | |
2157 | ||
2158 | if (!td || td->limit_index != LIMIT_LOW || op != REQ_OP_READ || | |
2159 | !blk_queue_nonrot(td->queue)) | |
2160 | return; | |
2161 | ||
2162 | index = request_bucket_index(size); | |
2163 | ||
2164 | latency = get_cpu_ptr(td->latency_buckets); | |
2165 | latency[index].total_latency += time; | |
2166 | latency[index].samples++; | |
2167 | put_cpu_ptr(td->latency_buckets); | |
2168 | } | |
2169 | ||
2170 | void blk_throtl_stat_add(struct request *rq, u64 time_ns) | |
2171 | { | |
2172 | struct request_queue *q = rq->q; | |
2173 | struct throtl_data *td = q->td; | |
2174 | ||
2175 | throtl_track_latency(td, blk_stat_size(&rq->issue_stat), | |
2176 | req_op(rq), time_ns >> 10); | |
2177 | } | |
2178 | ||
9e234eea SL |
2179 | void blk_throtl_bio_endio(struct bio *bio) |
2180 | { | |
2181 | struct throtl_grp *tg; | |
b9147dd1 SL |
2182 | u64 finish_time_ns; |
2183 | unsigned long finish_time; | |
2184 | unsigned long start_time; | |
2185 | unsigned long lat; | |
9e234eea SL |
2186 | |
2187 | tg = bio->bi_cg_private; | |
2188 | if (!tg) | |
2189 | return; | |
2190 | bio->bi_cg_private = NULL; | |
2191 | ||
b9147dd1 SL |
2192 | finish_time_ns = ktime_get_ns(); |
2193 | tg->last_finish_time = finish_time_ns >> 10; | |
2194 | ||
2195 | start_time = blk_stat_time(&bio->bi_issue_stat) >> 10; | |
2196 | finish_time = __blk_stat_time(finish_time_ns) >> 10; | |
2197 | /* this is only for bio based driver */ | |
2198 | if (start_time && finish_time > start_time && | |
2199 | !(bio->bi_issue_stat.stat & SKIP_LATENCY)) { | |
2200 | lat = finish_time - start_time; | |
2201 | throtl_track_latency(tg->td, blk_stat_size(&bio->bi_issue_stat), | |
2202 | bio_op(bio), lat); | |
2203 | } | |
9e234eea SL |
2204 | } |
2205 | #endif | |
2206 | ||
2a12f0dc TH |
2207 | /* |
2208 | * Dispatch all bios from all children tg's queued on @parent_sq. On | |
2209 | * return, @parent_sq is guaranteed to not have any active children tg's | |
2210 | * and all bios from previously active tg's are on @parent_sq->bio_lists[]. | |
2211 | */ | |
2212 | static void tg_drain_bios(struct throtl_service_queue *parent_sq) | |
2213 | { | |
2214 | struct throtl_grp *tg; | |
2215 | ||
2216 | while ((tg = throtl_rb_first(parent_sq))) { | |
2217 | struct throtl_service_queue *sq = &tg->service_queue; | |
2218 | struct bio *bio; | |
2219 | ||
2220 | throtl_dequeue_tg(tg); | |
2221 | ||
c5cc2070 | 2222 | while ((bio = throtl_peek_queued(&sq->queued[READ]))) |
2a12f0dc | 2223 | tg_dispatch_one_bio(tg, bio_data_dir(bio)); |
c5cc2070 | 2224 | while ((bio = throtl_peek_queued(&sq->queued[WRITE]))) |
2a12f0dc TH |
2225 | tg_dispatch_one_bio(tg, bio_data_dir(bio)); |
2226 | } | |
2227 | } | |
2228 | ||
c9a929dd TH |
2229 | /** |
2230 | * blk_throtl_drain - drain throttled bios | |
2231 | * @q: request_queue to drain throttled bios for | |
2232 | * | |
2233 | * Dispatch all currently throttled bios on @q through ->make_request_fn(). | |
2234 | */ | |
2235 | void blk_throtl_drain(struct request_queue *q) | |
2236 | __releases(q->queue_lock) __acquires(q->queue_lock) | |
2237 | { | |
2238 | struct throtl_data *td = q->td; | |
2a12f0dc | 2239 | struct blkcg_gq *blkg; |
492eb21b | 2240 | struct cgroup_subsys_state *pos_css; |
c9a929dd | 2241 | struct bio *bio; |
651930bc | 2242 | int rw; |
c9a929dd | 2243 | |
8bcb6c7d | 2244 | queue_lockdep_assert_held(q); |
2a12f0dc | 2245 | rcu_read_lock(); |
c9a929dd | 2246 | |
2a12f0dc TH |
2247 | /* |
2248 | * Drain each tg while doing post-order walk on the blkg tree, so | |
2249 | * that all bios are propagated to td->service_queue. It'd be | |
2250 | * better to walk service_queue tree directly but blkg walk is | |
2251 | * easier. | |
2252 | */ | |
492eb21b | 2253 | blkg_for_each_descendant_post(blkg, pos_css, td->queue->root_blkg) |
2a12f0dc | 2254 | tg_drain_bios(&blkg_to_tg(blkg)->service_queue); |
73f0d49a | 2255 | |
2a12f0dc TH |
2256 | /* finally, transfer bios from top-level tg's into the td */ |
2257 | tg_drain_bios(&td->service_queue); | |
2258 | ||
2259 | rcu_read_unlock(); | |
c9a929dd TH |
2260 | spin_unlock_irq(q->queue_lock); |
2261 | ||
2a12f0dc | 2262 | /* all bios now should be in td->service_queue, issue them */ |
651930bc | 2263 | for (rw = READ; rw <= WRITE; rw++) |
c5cc2070 TH |
2264 | while ((bio = throtl_pop_queued(&td->service_queue.queued[rw], |
2265 | NULL))) | |
651930bc | 2266 | generic_make_request(bio); |
c9a929dd TH |
2267 | |
2268 | spin_lock_irq(q->queue_lock); | |
2269 | } | |
2270 | ||
e43473b7 VG |
2271 | int blk_throtl_init(struct request_queue *q) |
2272 | { | |
2273 | struct throtl_data *td; | |
a2b1693b | 2274 | int ret; |
e43473b7 VG |
2275 | |
2276 | td = kzalloc_node(sizeof(*td), GFP_KERNEL, q->node); | |
2277 | if (!td) | |
2278 | return -ENOMEM; | |
b9147dd1 SL |
2279 | td->latency_buckets = __alloc_percpu(sizeof(struct latency_bucket) * |
2280 | LATENCY_BUCKET_SIZE, __alignof__(u64)); | |
2281 | if (!td->latency_buckets) { | |
2282 | kfree(td); | |
2283 | return -ENOMEM; | |
2284 | } | |
e43473b7 | 2285 | |
69df0ab0 | 2286 | INIT_WORK(&td->dispatch_work, blk_throtl_dispatch_work_fn); |
b2ce2643 | 2287 | throtl_service_queue_init(&td->service_queue); |
e43473b7 | 2288 | |
cd1604fa | 2289 | q->td = td; |
29b12589 | 2290 | td->queue = q; |
02977e4a | 2291 | |
9f626e37 | 2292 | td->limit_valid[LIMIT_MAX] = true; |
cd5ab1b0 | 2293 | td->limit_index = LIMIT_MAX; |
3f0abd80 SL |
2294 | td->low_upgrade_time = jiffies; |
2295 | td->low_downgrade_time = jiffies; | |
9e234eea | 2296 | |
a2b1693b | 2297 | /* activate policy */ |
3c798398 | 2298 | ret = blkcg_activate_policy(q, &blkcg_policy_throtl); |
b9147dd1 SL |
2299 | if (ret) { |
2300 | free_percpu(td->latency_buckets); | |
f51b802c | 2301 | kfree(td); |
b9147dd1 | 2302 | } |
a2b1693b | 2303 | return ret; |
e43473b7 VG |
2304 | } |
2305 | ||
2306 | void blk_throtl_exit(struct request_queue *q) | |
2307 | { | |
c875f4d0 | 2308 | BUG_ON(!q->td); |
da527770 | 2309 | throtl_shutdown_wq(q); |
3c798398 | 2310 | blkcg_deactivate_policy(q, &blkcg_policy_throtl); |
b9147dd1 | 2311 | free_percpu(q->td->latency_buckets); |
c9a929dd | 2312 | kfree(q->td); |
e43473b7 VG |
2313 | } |
2314 | ||
d61fcfa4 SL |
2315 | void blk_throtl_register_queue(struct request_queue *q) |
2316 | { | |
2317 | struct throtl_data *td; | |
9e234eea SL |
2318 | struct cgroup_subsys_state *pos_css; |
2319 | struct blkcg_gq *blkg; | |
d61fcfa4 SL |
2320 | |
2321 | td = q->td; | |
2322 | BUG_ON(!td); | |
2323 | ||
ada75b6e | 2324 | if (blk_queue_nonrot(q)) { |
d61fcfa4 | 2325 | td->throtl_slice = DFL_THROTL_SLICE_SSD; |
ada75b6e SL |
2326 | td->dft_idletime_threshold = DFL_IDLE_THRESHOLD_SSD; |
2327 | } else { | |
d61fcfa4 | 2328 | td->throtl_slice = DFL_THROTL_SLICE_HD; |
ada75b6e SL |
2329 | td->dft_idletime_threshold = DFL_IDLE_THRESHOLD_HD; |
2330 | } | |
d61fcfa4 SL |
2331 | #ifndef CONFIG_BLK_DEV_THROTTLING_LOW |
2332 | /* if no low limit, use previous default */ | |
2333 | td->throtl_slice = DFL_THROTL_SLICE_HD; | |
2334 | #endif | |
9e234eea | 2335 | |
b9147dd1 SL |
2336 | td->track_bio_latency = !q->mq_ops && !q->request_fn; |
2337 | if (!td->track_bio_latency) | |
2338 | blk_stat_enable_accounting(q); | |
2339 | ||
9e234eea SL |
2340 | /* |
2341 | * some tg are created before queue is fully initialized, eg, nonrot | |
2342 | * isn't initialized yet | |
2343 | */ | |
2344 | rcu_read_lock(); | |
2345 | blkg_for_each_descendant_post(blkg, pos_css, q->root_blkg) { | |
2346 | struct throtl_grp *tg = blkg_to_tg(blkg); | |
2347 | ||
ada75b6e | 2348 | tg->idletime_threshold = td->dft_idletime_threshold; |
9e234eea SL |
2349 | } |
2350 | rcu_read_unlock(); | |
d61fcfa4 SL |
2351 | } |
2352 | ||
297e3d85 SL |
2353 | #ifdef CONFIG_BLK_DEV_THROTTLING_LOW |
2354 | ssize_t blk_throtl_sample_time_show(struct request_queue *q, char *page) | |
2355 | { | |
2356 | if (!q->td) | |
2357 | return -EINVAL; | |
2358 | return sprintf(page, "%u\n", jiffies_to_msecs(q->td->throtl_slice)); | |
2359 | } | |
2360 | ||
2361 | ssize_t blk_throtl_sample_time_store(struct request_queue *q, | |
2362 | const char *page, size_t count) | |
2363 | { | |
2364 | unsigned long v; | |
2365 | unsigned long t; | |
2366 | ||
2367 | if (!q->td) | |
2368 | return -EINVAL; | |
2369 | if (kstrtoul(page, 10, &v)) | |
2370 | return -EINVAL; | |
2371 | t = msecs_to_jiffies(v); | |
2372 | if (t == 0 || t > MAX_THROTL_SLICE) | |
2373 | return -EINVAL; | |
2374 | q->td->throtl_slice = t; | |
2375 | return count; | |
2376 | } | |
2377 | #endif | |
2378 | ||
e43473b7 VG |
2379 | static int __init throtl_init(void) |
2380 | { | |
450adcbe VG |
2381 | kthrotld_workqueue = alloc_workqueue("kthrotld", WQ_MEM_RECLAIM, 0); |
2382 | if (!kthrotld_workqueue) | |
2383 | panic("Failed to create kthrotld\n"); | |
2384 | ||
3c798398 | 2385 | return blkcg_policy_register(&blkcg_policy_throtl); |
e43473b7 VG |
2386 | } |
2387 | ||
2388 | module_init(throtl_init); |