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) |
e43473b7 | 25 | |
3c798398 | 26 | static struct blkcg_policy blkcg_policy_throtl; |
0381411e | 27 | |
450adcbe VG |
28 | /* A workqueue to queue throttle related work */ |
29 | static struct workqueue_struct *kthrotld_workqueue; | |
450adcbe | 30 | |
c5cc2070 TH |
31 | /* |
32 | * To implement hierarchical throttling, throtl_grps form a tree and bios | |
33 | * are dispatched upwards level by level until they reach the top and get | |
34 | * issued. When dispatching bios from the children and local group at each | |
35 | * level, if the bios are dispatched into a single bio_list, there's a risk | |
36 | * of a local or child group which can queue many bios at once filling up | |
37 | * the list starving others. | |
38 | * | |
39 | * To avoid such starvation, dispatched bios are queued separately | |
40 | * according to where they came from. When they are again dispatched to | |
41 | * the parent, they're popped in round-robin order so that no single source | |
42 | * hogs the dispatch window. | |
43 | * | |
44 | * throtl_qnode is used to keep the queued bios separated by their sources. | |
45 | * Bios are queued to throtl_qnode which in turn is queued to | |
46 | * throtl_service_queue and then dispatched in round-robin order. | |
47 | * | |
48 | * It's also used to track the reference counts on blkg's. A qnode always | |
49 | * belongs to a throtl_grp and gets queued on itself or the parent, so | |
50 | * incrementing the reference of the associated throtl_grp when a qnode is | |
51 | * queued and decrementing when dequeued is enough to keep the whole blkg | |
52 | * tree pinned while bios are in flight. | |
53 | */ | |
54 | struct throtl_qnode { | |
55 | struct list_head node; /* service_queue->queued[] */ | |
56 | struct bio_list bios; /* queued bios */ | |
57 | struct throtl_grp *tg; /* tg this qnode belongs to */ | |
58 | }; | |
59 | ||
c9e0332e | 60 | struct throtl_service_queue { |
77216b04 TH |
61 | struct throtl_service_queue *parent_sq; /* the parent service_queue */ |
62 | ||
73f0d49a TH |
63 | /* |
64 | * Bios queued directly to this service_queue or dispatched from | |
65 | * children throtl_grp's. | |
66 | */ | |
c5cc2070 | 67 | struct list_head queued[2]; /* throtl_qnode [READ/WRITE] */ |
73f0d49a TH |
68 | unsigned int nr_queued[2]; /* number of queued bios */ |
69 | ||
70 | /* | |
71 | * RB tree of active children throtl_grp's, which are sorted by | |
72 | * their ->disptime. | |
73 | */ | |
c9e0332e TH |
74 | struct rb_root pending_tree; /* RB tree of active tgs */ |
75 | struct rb_node *first_pending; /* first node in the tree */ | |
76 | unsigned int nr_pending; /* # queued in the tree */ | |
77 | unsigned long first_pending_disptime; /* disptime of the first tg */ | |
69df0ab0 | 78 | struct timer_list pending_timer; /* fires on first_pending_disptime */ |
e43473b7 VG |
79 | }; |
80 | ||
5b2c16aa TH |
81 | enum tg_state_flags { |
82 | THROTL_TG_PENDING = 1 << 0, /* on parent's pending tree */ | |
0e9f4164 | 83 | THROTL_TG_WAS_EMPTY = 1 << 1, /* bio_lists[] became non-empty */ |
5b2c16aa TH |
84 | }; |
85 | ||
e43473b7 VG |
86 | #define rb_entry_tg(node) rb_entry((node), struct throtl_grp, rb_node) |
87 | ||
9f626e37 | 88 | enum { |
cd5ab1b0 | 89 | LIMIT_LOW, |
9f626e37 SL |
90 | LIMIT_MAX, |
91 | LIMIT_CNT, | |
92 | }; | |
93 | ||
e43473b7 | 94 | struct throtl_grp { |
f95a04af TH |
95 | /* must be the first member */ |
96 | struct blkg_policy_data pd; | |
97 | ||
c9e0332e | 98 | /* active throtl group service_queue member */ |
e43473b7 VG |
99 | struct rb_node rb_node; |
100 | ||
0f3457f6 TH |
101 | /* throtl_data this group belongs to */ |
102 | struct throtl_data *td; | |
103 | ||
49a2f1e3 TH |
104 | /* this group's service queue */ |
105 | struct throtl_service_queue service_queue; | |
106 | ||
c5cc2070 TH |
107 | /* |
108 | * qnode_on_self is used when bios are directly queued to this | |
109 | * throtl_grp so that local bios compete fairly with bios | |
110 | * dispatched from children. qnode_on_parent is used when bios are | |
111 | * dispatched from this throtl_grp into its parent and will compete | |
112 | * with the sibling qnode_on_parents and the parent's | |
113 | * qnode_on_self. | |
114 | */ | |
115 | struct throtl_qnode qnode_on_self[2]; | |
116 | struct throtl_qnode qnode_on_parent[2]; | |
117 | ||
e43473b7 VG |
118 | /* |
119 | * Dispatch time in jiffies. This is the estimated time when group | |
120 | * will unthrottle and is ready to dispatch more bio. It is used as | |
121 | * key to sort active groups in service tree. | |
122 | */ | |
123 | unsigned long disptime; | |
124 | ||
e43473b7 VG |
125 | unsigned int flags; |
126 | ||
693e751e TH |
127 | /* are there any throtl rules between this group and td? */ |
128 | bool has_rules[2]; | |
129 | ||
cd5ab1b0 | 130 | /* internally used bytes per second rate limits */ |
9f626e37 | 131 | uint64_t bps[2][LIMIT_CNT]; |
cd5ab1b0 SL |
132 | /* user configured bps limits */ |
133 | uint64_t bps_conf[2][LIMIT_CNT]; | |
e43473b7 | 134 | |
cd5ab1b0 | 135 | /* internally used IOPS limits */ |
9f626e37 | 136 | unsigned int iops[2][LIMIT_CNT]; |
cd5ab1b0 SL |
137 | /* user configured IOPS limits */ |
138 | unsigned int iops_conf[2][LIMIT_CNT]; | |
8e89d13f | 139 | |
e43473b7 VG |
140 | /* Number of bytes disptached in current slice */ |
141 | uint64_t bytes_disp[2]; | |
8e89d13f VG |
142 | /* Number of bio's dispatched in current slice */ |
143 | unsigned int io_disp[2]; | |
e43473b7 | 144 | |
3f0abd80 SL |
145 | unsigned long last_low_overflow_time[2]; |
146 | ||
147 | uint64_t last_bytes_disp[2]; | |
148 | unsigned int last_io_disp[2]; | |
149 | ||
150 | unsigned long last_check_time; | |
151 | ||
aec24246 SL |
152 | unsigned long last_dispatch_time[2]; |
153 | ||
e43473b7 VG |
154 | /* When did we start a new slice */ |
155 | unsigned long slice_start[2]; | |
156 | unsigned long slice_end[2]; | |
157 | }; | |
158 | ||
159 | struct throtl_data | |
160 | { | |
e43473b7 | 161 | /* service tree for active throtl groups */ |
c9e0332e | 162 | struct throtl_service_queue service_queue; |
e43473b7 | 163 | |
e43473b7 VG |
164 | struct request_queue *queue; |
165 | ||
166 | /* Total Number of queued bios on READ and WRITE lists */ | |
167 | unsigned int nr_queued[2]; | |
168 | ||
297e3d85 SL |
169 | unsigned int throtl_slice; |
170 | ||
e43473b7 | 171 | /* Work for dispatching throttled bios */ |
69df0ab0 | 172 | struct work_struct dispatch_work; |
9f626e37 SL |
173 | unsigned int limit_index; |
174 | bool limit_valid[LIMIT_CNT]; | |
3f0abd80 SL |
175 | |
176 | unsigned long low_upgrade_time; | |
177 | unsigned long low_downgrade_time; | |
7394e31f SL |
178 | |
179 | unsigned int scale; | |
e43473b7 VG |
180 | }; |
181 | ||
69df0ab0 TH |
182 | static void throtl_pending_timer_fn(unsigned long arg); |
183 | ||
f95a04af TH |
184 | static inline struct throtl_grp *pd_to_tg(struct blkg_policy_data *pd) |
185 | { | |
186 | return pd ? container_of(pd, struct throtl_grp, pd) : NULL; | |
187 | } | |
188 | ||
3c798398 | 189 | static inline struct throtl_grp *blkg_to_tg(struct blkcg_gq *blkg) |
0381411e | 190 | { |
f95a04af | 191 | return pd_to_tg(blkg_to_pd(blkg, &blkcg_policy_throtl)); |
0381411e TH |
192 | } |
193 | ||
3c798398 | 194 | static inline struct blkcg_gq *tg_to_blkg(struct throtl_grp *tg) |
0381411e | 195 | { |
f95a04af | 196 | return pd_to_blkg(&tg->pd); |
0381411e TH |
197 | } |
198 | ||
fda6f272 TH |
199 | /** |
200 | * sq_to_tg - return the throl_grp the specified service queue belongs to | |
201 | * @sq: the throtl_service_queue of interest | |
202 | * | |
203 | * Return the throtl_grp @sq belongs to. If @sq is the top-level one | |
204 | * embedded in throtl_data, %NULL is returned. | |
205 | */ | |
206 | static struct throtl_grp *sq_to_tg(struct throtl_service_queue *sq) | |
207 | { | |
208 | if (sq && sq->parent_sq) | |
209 | return container_of(sq, struct throtl_grp, service_queue); | |
210 | else | |
211 | return NULL; | |
212 | } | |
213 | ||
214 | /** | |
215 | * sq_to_td - return throtl_data the specified service queue belongs to | |
216 | * @sq: the throtl_service_queue of interest | |
217 | * | |
b43daedc | 218 | * A service_queue can be embedded in either a throtl_grp or throtl_data. |
fda6f272 TH |
219 | * Determine the associated throtl_data accordingly and return it. |
220 | */ | |
221 | static struct throtl_data *sq_to_td(struct throtl_service_queue *sq) | |
222 | { | |
223 | struct throtl_grp *tg = sq_to_tg(sq); | |
224 | ||
225 | if (tg) | |
226 | return tg->td; | |
227 | else | |
228 | return container_of(sq, struct throtl_data, service_queue); | |
229 | } | |
230 | ||
7394e31f SL |
231 | /* |
232 | * cgroup's limit in LIMIT_MAX is scaled if low limit is set. This scale is to | |
233 | * make the IO dispatch more smooth. | |
234 | * Scale up: linearly scale up according to lapsed time since upgrade. For | |
235 | * every throtl_slice, the limit scales up 1/2 .low limit till the | |
236 | * limit hits .max limit | |
237 | * Scale down: exponentially scale down if a cgroup doesn't hit its .low limit | |
238 | */ | |
239 | static uint64_t throtl_adjusted_limit(uint64_t low, struct throtl_data *td) | |
240 | { | |
241 | /* arbitrary value to avoid too big scale */ | |
242 | if (td->scale < 4096 && time_after_eq(jiffies, | |
243 | td->low_upgrade_time + td->scale * td->throtl_slice)) | |
244 | td->scale = (jiffies - td->low_upgrade_time) / td->throtl_slice; | |
245 | ||
246 | return low + (low >> 1) * td->scale; | |
247 | } | |
248 | ||
9f626e37 SL |
249 | static uint64_t tg_bps_limit(struct throtl_grp *tg, int rw) |
250 | { | |
b22c417c | 251 | struct blkcg_gq *blkg = tg_to_blkg(tg); |
7394e31f | 252 | struct throtl_data *td; |
b22c417c SL |
253 | uint64_t ret; |
254 | ||
255 | if (cgroup_subsys_on_dfl(io_cgrp_subsys) && !blkg->parent) | |
256 | return U64_MAX; | |
7394e31f SL |
257 | |
258 | td = tg->td; | |
259 | ret = tg->bps[rw][td->limit_index]; | |
260 | if (ret == 0 && td->limit_index == LIMIT_LOW) | |
b22c417c | 261 | return tg->bps[rw][LIMIT_MAX]; |
7394e31f SL |
262 | |
263 | if (td->limit_index == LIMIT_MAX && tg->bps[rw][LIMIT_LOW] && | |
264 | tg->bps[rw][LIMIT_LOW] != tg->bps[rw][LIMIT_MAX]) { | |
265 | uint64_t adjusted; | |
266 | ||
267 | adjusted = throtl_adjusted_limit(tg->bps[rw][LIMIT_LOW], td); | |
268 | ret = min(tg->bps[rw][LIMIT_MAX], adjusted); | |
269 | } | |
b22c417c | 270 | return ret; |
9f626e37 SL |
271 | } |
272 | ||
273 | static unsigned int tg_iops_limit(struct throtl_grp *tg, int rw) | |
274 | { | |
b22c417c | 275 | struct blkcg_gq *blkg = tg_to_blkg(tg); |
7394e31f | 276 | struct throtl_data *td; |
b22c417c SL |
277 | unsigned int ret; |
278 | ||
279 | if (cgroup_subsys_on_dfl(io_cgrp_subsys) && !blkg->parent) | |
280 | return UINT_MAX; | |
7394e31f SL |
281 | td = tg->td; |
282 | ret = tg->iops[rw][td->limit_index]; | |
b22c417c SL |
283 | if (ret == 0 && tg->td->limit_index == LIMIT_LOW) |
284 | return tg->iops[rw][LIMIT_MAX]; | |
7394e31f SL |
285 | |
286 | if (td->limit_index == LIMIT_MAX && tg->iops[rw][LIMIT_LOW] && | |
287 | tg->iops[rw][LIMIT_LOW] != tg->iops[rw][LIMIT_MAX]) { | |
288 | uint64_t adjusted; | |
289 | ||
290 | adjusted = throtl_adjusted_limit(tg->iops[rw][LIMIT_LOW], td); | |
291 | if (adjusted > UINT_MAX) | |
292 | adjusted = UINT_MAX; | |
293 | ret = min_t(unsigned int, tg->iops[rw][LIMIT_MAX], adjusted); | |
294 | } | |
b22c417c | 295 | return ret; |
9f626e37 SL |
296 | } |
297 | ||
fda6f272 TH |
298 | /** |
299 | * throtl_log - log debug message via blktrace | |
300 | * @sq: the service_queue being reported | |
301 | * @fmt: printf format string | |
302 | * @args: printf args | |
303 | * | |
304 | * The messages are prefixed with "throtl BLKG_NAME" if @sq belongs to a | |
305 | * throtl_grp; otherwise, just "throtl". | |
fda6f272 TH |
306 | */ |
307 | #define throtl_log(sq, fmt, args...) do { \ | |
308 | struct throtl_grp *__tg = sq_to_tg((sq)); \ | |
309 | struct throtl_data *__td = sq_to_td((sq)); \ | |
310 | \ | |
311 | (void)__td; \ | |
59fa0224 SL |
312 | if (likely(!blk_trace_note_message_enabled(__td->queue))) \ |
313 | break; \ | |
fda6f272 TH |
314 | if ((__tg)) { \ |
315 | char __pbuf[128]; \ | |
54e7ed12 | 316 | \ |
fda6f272 TH |
317 | blkg_path(tg_to_blkg(__tg), __pbuf, sizeof(__pbuf)); \ |
318 | blk_add_trace_msg(__td->queue, "throtl %s " fmt, __pbuf, ##args); \ | |
319 | } else { \ | |
320 | blk_add_trace_msg(__td->queue, "throtl " fmt, ##args); \ | |
321 | } \ | |
54e7ed12 | 322 | } while (0) |
e43473b7 | 323 | |
c5cc2070 TH |
324 | static void throtl_qnode_init(struct throtl_qnode *qn, struct throtl_grp *tg) |
325 | { | |
326 | INIT_LIST_HEAD(&qn->node); | |
327 | bio_list_init(&qn->bios); | |
328 | qn->tg = tg; | |
329 | } | |
330 | ||
331 | /** | |
332 | * throtl_qnode_add_bio - add a bio to a throtl_qnode and activate it | |
333 | * @bio: bio being added | |
334 | * @qn: qnode to add bio to | |
335 | * @queued: the service_queue->queued[] list @qn belongs to | |
336 | * | |
337 | * Add @bio to @qn and put @qn on @queued if it's not already on. | |
338 | * @qn->tg's reference count is bumped when @qn is activated. See the | |
339 | * comment on top of throtl_qnode definition for details. | |
340 | */ | |
341 | static void throtl_qnode_add_bio(struct bio *bio, struct throtl_qnode *qn, | |
342 | struct list_head *queued) | |
343 | { | |
344 | bio_list_add(&qn->bios, bio); | |
345 | if (list_empty(&qn->node)) { | |
346 | list_add_tail(&qn->node, queued); | |
347 | blkg_get(tg_to_blkg(qn->tg)); | |
348 | } | |
349 | } | |
350 | ||
351 | /** | |
352 | * throtl_peek_queued - peek the first bio on a qnode list | |
353 | * @queued: the qnode list to peek | |
354 | */ | |
355 | static struct bio *throtl_peek_queued(struct list_head *queued) | |
356 | { | |
357 | struct throtl_qnode *qn = list_first_entry(queued, struct throtl_qnode, node); | |
358 | struct bio *bio; | |
359 | ||
360 | if (list_empty(queued)) | |
361 | return NULL; | |
362 | ||
363 | bio = bio_list_peek(&qn->bios); | |
364 | WARN_ON_ONCE(!bio); | |
365 | return bio; | |
366 | } | |
367 | ||
368 | /** | |
369 | * throtl_pop_queued - pop the first bio form a qnode list | |
370 | * @queued: the qnode list to pop a bio from | |
371 | * @tg_to_put: optional out argument for throtl_grp to put | |
372 | * | |
373 | * Pop the first bio from the qnode list @queued. After popping, the first | |
374 | * qnode is removed from @queued if empty or moved to the end of @queued so | |
375 | * that the popping order is round-robin. | |
376 | * | |
377 | * When the first qnode is removed, its associated throtl_grp should be put | |
378 | * too. If @tg_to_put is NULL, this function automatically puts it; | |
379 | * otherwise, *@tg_to_put is set to the throtl_grp to put and the caller is | |
380 | * responsible for putting it. | |
381 | */ | |
382 | static struct bio *throtl_pop_queued(struct list_head *queued, | |
383 | struct throtl_grp **tg_to_put) | |
384 | { | |
385 | struct throtl_qnode *qn = list_first_entry(queued, struct throtl_qnode, node); | |
386 | struct bio *bio; | |
387 | ||
388 | if (list_empty(queued)) | |
389 | return NULL; | |
390 | ||
391 | bio = bio_list_pop(&qn->bios); | |
392 | WARN_ON_ONCE(!bio); | |
393 | ||
394 | if (bio_list_empty(&qn->bios)) { | |
395 | list_del_init(&qn->node); | |
396 | if (tg_to_put) | |
397 | *tg_to_put = qn->tg; | |
398 | else | |
399 | blkg_put(tg_to_blkg(qn->tg)); | |
400 | } else { | |
401 | list_move_tail(&qn->node, queued); | |
402 | } | |
403 | ||
404 | return bio; | |
405 | } | |
406 | ||
49a2f1e3 | 407 | /* init a service_queue, assumes the caller zeroed it */ |
b2ce2643 | 408 | static void throtl_service_queue_init(struct throtl_service_queue *sq) |
49a2f1e3 | 409 | { |
c5cc2070 TH |
410 | INIT_LIST_HEAD(&sq->queued[0]); |
411 | INIT_LIST_HEAD(&sq->queued[1]); | |
49a2f1e3 | 412 | sq->pending_tree = RB_ROOT; |
69df0ab0 TH |
413 | setup_timer(&sq->pending_timer, throtl_pending_timer_fn, |
414 | (unsigned long)sq); | |
415 | } | |
416 | ||
001bea73 TH |
417 | static struct blkg_policy_data *throtl_pd_alloc(gfp_t gfp, int node) |
418 | { | |
4fb72036 | 419 | struct throtl_grp *tg; |
24bdb8ef | 420 | int rw; |
4fb72036 TH |
421 | |
422 | tg = kzalloc_node(sizeof(*tg), gfp, node); | |
423 | if (!tg) | |
77ea7338 | 424 | return NULL; |
4fb72036 | 425 | |
b2ce2643 TH |
426 | throtl_service_queue_init(&tg->service_queue); |
427 | ||
428 | for (rw = READ; rw <= WRITE; rw++) { | |
429 | throtl_qnode_init(&tg->qnode_on_self[rw], tg); | |
430 | throtl_qnode_init(&tg->qnode_on_parent[rw], tg); | |
431 | } | |
432 | ||
433 | RB_CLEAR_NODE(&tg->rb_node); | |
9f626e37 SL |
434 | tg->bps[READ][LIMIT_MAX] = U64_MAX; |
435 | tg->bps[WRITE][LIMIT_MAX] = U64_MAX; | |
436 | tg->iops[READ][LIMIT_MAX] = UINT_MAX; | |
437 | tg->iops[WRITE][LIMIT_MAX] = UINT_MAX; | |
cd5ab1b0 SL |
438 | tg->bps_conf[READ][LIMIT_MAX] = U64_MAX; |
439 | tg->bps_conf[WRITE][LIMIT_MAX] = U64_MAX; | |
440 | tg->iops_conf[READ][LIMIT_MAX] = UINT_MAX; | |
441 | tg->iops_conf[WRITE][LIMIT_MAX] = UINT_MAX; | |
442 | /* LIMIT_LOW will have default value 0 */ | |
b2ce2643 | 443 | |
4fb72036 | 444 | return &tg->pd; |
001bea73 TH |
445 | } |
446 | ||
a9520cd6 | 447 | static void throtl_pd_init(struct blkg_policy_data *pd) |
a29a171e | 448 | { |
a9520cd6 TH |
449 | struct throtl_grp *tg = pd_to_tg(pd); |
450 | struct blkcg_gq *blkg = tg_to_blkg(tg); | |
77216b04 | 451 | struct throtl_data *td = blkg->q->td; |
b2ce2643 | 452 | struct throtl_service_queue *sq = &tg->service_queue; |
cd1604fa | 453 | |
9138125b | 454 | /* |
aa6ec29b | 455 | * If on the default hierarchy, we switch to properly hierarchical |
9138125b TH |
456 | * behavior where limits on a given throtl_grp are applied to the |
457 | * whole subtree rather than just the group itself. e.g. If 16M | |
458 | * read_bps limit is set on the root group, the whole system can't | |
459 | * exceed 16M for the device. | |
460 | * | |
aa6ec29b | 461 | * If not on the default hierarchy, the broken flat hierarchy |
9138125b TH |
462 | * behavior is retained where all throtl_grps are treated as if |
463 | * they're all separate root groups right below throtl_data. | |
464 | * Limits of a group don't interact with limits of other groups | |
465 | * regardless of the position of the group in the hierarchy. | |
466 | */ | |
b2ce2643 | 467 | sq->parent_sq = &td->service_queue; |
9e10a130 | 468 | if (cgroup_subsys_on_dfl(io_cgrp_subsys) && blkg->parent) |
b2ce2643 | 469 | sq->parent_sq = &blkg_to_tg(blkg->parent)->service_queue; |
77216b04 | 470 | tg->td = td; |
8a3d2615 TH |
471 | } |
472 | ||
693e751e TH |
473 | /* |
474 | * Set has_rules[] if @tg or any of its parents have limits configured. | |
475 | * This doesn't require walking up to the top of the hierarchy as the | |
476 | * parent's has_rules[] is guaranteed to be correct. | |
477 | */ | |
478 | static void tg_update_has_rules(struct throtl_grp *tg) | |
479 | { | |
480 | struct throtl_grp *parent_tg = sq_to_tg(tg->service_queue.parent_sq); | |
9f626e37 | 481 | struct throtl_data *td = tg->td; |
693e751e TH |
482 | int rw; |
483 | ||
484 | for (rw = READ; rw <= WRITE; rw++) | |
485 | tg->has_rules[rw] = (parent_tg && parent_tg->has_rules[rw]) || | |
9f626e37 SL |
486 | (td->limit_valid[td->limit_index] && |
487 | (tg_bps_limit(tg, rw) != U64_MAX || | |
488 | tg_iops_limit(tg, rw) != UINT_MAX)); | |
693e751e TH |
489 | } |
490 | ||
a9520cd6 | 491 | static void throtl_pd_online(struct blkg_policy_data *pd) |
693e751e | 492 | { |
aec24246 | 493 | struct throtl_grp *tg = pd_to_tg(pd); |
693e751e TH |
494 | /* |
495 | * We don't want new groups to escape the limits of its ancestors. | |
496 | * Update has_rules[] after a new group is brought online. | |
497 | */ | |
aec24246 SL |
498 | tg_update_has_rules(tg); |
499 | tg->last_dispatch_time[READ] = jiffies; | |
500 | tg->last_dispatch_time[WRITE] = jiffies; | |
693e751e TH |
501 | } |
502 | ||
cd5ab1b0 SL |
503 | static void blk_throtl_update_limit_valid(struct throtl_data *td) |
504 | { | |
505 | struct cgroup_subsys_state *pos_css; | |
506 | struct blkcg_gq *blkg; | |
507 | bool low_valid = false; | |
508 | ||
509 | rcu_read_lock(); | |
510 | blkg_for_each_descendant_post(blkg, pos_css, td->queue->root_blkg) { | |
511 | struct throtl_grp *tg = blkg_to_tg(blkg); | |
512 | ||
513 | if (tg->bps[READ][LIMIT_LOW] || tg->bps[WRITE][LIMIT_LOW] || | |
514 | tg->iops[READ][LIMIT_LOW] || tg->iops[WRITE][LIMIT_LOW]) | |
515 | low_valid = true; | |
516 | } | |
517 | rcu_read_unlock(); | |
518 | ||
519 | td->limit_valid[LIMIT_LOW] = low_valid; | |
520 | } | |
521 | ||
c79892c5 | 522 | static void throtl_upgrade_state(struct throtl_data *td); |
cd5ab1b0 SL |
523 | static void throtl_pd_offline(struct blkg_policy_data *pd) |
524 | { | |
525 | struct throtl_grp *tg = pd_to_tg(pd); | |
526 | ||
527 | tg->bps[READ][LIMIT_LOW] = 0; | |
528 | tg->bps[WRITE][LIMIT_LOW] = 0; | |
529 | tg->iops[READ][LIMIT_LOW] = 0; | |
530 | tg->iops[WRITE][LIMIT_LOW] = 0; | |
531 | ||
532 | blk_throtl_update_limit_valid(tg->td); | |
533 | ||
c79892c5 SL |
534 | if (!tg->td->limit_valid[tg->td->limit_index]) |
535 | throtl_upgrade_state(tg->td); | |
cd5ab1b0 SL |
536 | } |
537 | ||
001bea73 TH |
538 | static void throtl_pd_free(struct blkg_policy_data *pd) |
539 | { | |
4fb72036 TH |
540 | struct throtl_grp *tg = pd_to_tg(pd); |
541 | ||
b2ce2643 | 542 | del_timer_sync(&tg->service_queue.pending_timer); |
4fb72036 | 543 | kfree(tg); |
001bea73 TH |
544 | } |
545 | ||
0049af73 TH |
546 | static struct throtl_grp * |
547 | throtl_rb_first(struct throtl_service_queue *parent_sq) | |
e43473b7 VG |
548 | { |
549 | /* Service tree is empty */ | |
0049af73 | 550 | if (!parent_sq->nr_pending) |
e43473b7 VG |
551 | return NULL; |
552 | ||
0049af73 TH |
553 | if (!parent_sq->first_pending) |
554 | parent_sq->first_pending = rb_first(&parent_sq->pending_tree); | |
e43473b7 | 555 | |
0049af73 TH |
556 | if (parent_sq->first_pending) |
557 | return rb_entry_tg(parent_sq->first_pending); | |
e43473b7 VG |
558 | |
559 | return NULL; | |
560 | } | |
561 | ||
562 | static void rb_erase_init(struct rb_node *n, struct rb_root *root) | |
563 | { | |
564 | rb_erase(n, root); | |
565 | RB_CLEAR_NODE(n); | |
566 | } | |
567 | ||
0049af73 TH |
568 | static void throtl_rb_erase(struct rb_node *n, |
569 | struct throtl_service_queue *parent_sq) | |
e43473b7 | 570 | { |
0049af73 TH |
571 | if (parent_sq->first_pending == n) |
572 | parent_sq->first_pending = NULL; | |
573 | rb_erase_init(n, &parent_sq->pending_tree); | |
574 | --parent_sq->nr_pending; | |
e43473b7 VG |
575 | } |
576 | ||
0049af73 | 577 | static void update_min_dispatch_time(struct throtl_service_queue *parent_sq) |
e43473b7 VG |
578 | { |
579 | struct throtl_grp *tg; | |
580 | ||
0049af73 | 581 | tg = throtl_rb_first(parent_sq); |
e43473b7 VG |
582 | if (!tg) |
583 | return; | |
584 | ||
0049af73 | 585 | parent_sq->first_pending_disptime = tg->disptime; |
e43473b7 VG |
586 | } |
587 | ||
77216b04 | 588 | static void tg_service_queue_add(struct throtl_grp *tg) |
e43473b7 | 589 | { |
77216b04 | 590 | struct throtl_service_queue *parent_sq = tg->service_queue.parent_sq; |
0049af73 | 591 | struct rb_node **node = &parent_sq->pending_tree.rb_node; |
e43473b7 VG |
592 | struct rb_node *parent = NULL; |
593 | struct throtl_grp *__tg; | |
594 | unsigned long key = tg->disptime; | |
595 | int left = 1; | |
596 | ||
597 | while (*node != NULL) { | |
598 | parent = *node; | |
599 | __tg = rb_entry_tg(parent); | |
600 | ||
601 | if (time_before(key, __tg->disptime)) | |
602 | node = &parent->rb_left; | |
603 | else { | |
604 | node = &parent->rb_right; | |
605 | left = 0; | |
606 | } | |
607 | } | |
608 | ||
609 | if (left) | |
0049af73 | 610 | parent_sq->first_pending = &tg->rb_node; |
e43473b7 VG |
611 | |
612 | rb_link_node(&tg->rb_node, parent, node); | |
0049af73 | 613 | rb_insert_color(&tg->rb_node, &parent_sq->pending_tree); |
e43473b7 VG |
614 | } |
615 | ||
77216b04 | 616 | static void __throtl_enqueue_tg(struct throtl_grp *tg) |
e43473b7 | 617 | { |
77216b04 | 618 | tg_service_queue_add(tg); |
5b2c16aa | 619 | tg->flags |= THROTL_TG_PENDING; |
77216b04 | 620 | tg->service_queue.parent_sq->nr_pending++; |
e43473b7 VG |
621 | } |
622 | ||
77216b04 | 623 | static void throtl_enqueue_tg(struct throtl_grp *tg) |
e43473b7 | 624 | { |
5b2c16aa | 625 | if (!(tg->flags & THROTL_TG_PENDING)) |
77216b04 | 626 | __throtl_enqueue_tg(tg); |
e43473b7 VG |
627 | } |
628 | ||
77216b04 | 629 | static void __throtl_dequeue_tg(struct throtl_grp *tg) |
e43473b7 | 630 | { |
77216b04 | 631 | throtl_rb_erase(&tg->rb_node, tg->service_queue.parent_sq); |
5b2c16aa | 632 | tg->flags &= ~THROTL_TG_PENDING; |
e43473b7 VG |
633 | } |
634 | ||
77216b04 | 635 | static void throtl_dequeue_tg(struct throtl_grp *tg) |
e43473b7 | 636 | { |
5b2c16aa | 637 | if (tg->flags & THROTL_TG_PENDING) |
77216b04 | 638 | __throtl_dequeue_tg(tg); |
e43473b7 VG |
639 | } |
640 | ||
a9131a27 | 641 | /* Call with queue lock held */ |
69df0ab0 TH |
642 | static void throtl_schedule_pending_timer(struct throtl_service_queue *sq, |
643 | unsigned long expires) | |
a9131a27 | 644 | { |
297e3d85 | 645 | unsigned long max_expire = jiffies + 8 * sq_to_tg(sq)->td->throtl_slice; |
06cceedc SL |
646 | |
647 | /* | |
648 | * Since we are adjusting the throttle limit dynamically, the sleep | |
649 | * time calculated according to previous limit might be invalid. It's | |
650 | * possible the cgroup sleep time is very long and no other cgroups | |
651 | * have IO running so notify the limit changes. Make sure the cgroup | |
652 | * doesn't sleep too long to avoid the missed notification. | |
653 | */ | |
654 | if (time_after(expires, max_expire)) | |
655 | expires = max_expire; | |
69df0ab0 TH |
656 | mod_timer(&sq->pending_timer, expires); |
657 | throtl_log(sq, "schedule timer. delay=%lu jiffies=%lu", | |
658 | expires - jiffies, jiffies); | |
a9131a27 TH |
659 | } |
660 | ||
7f52f98c TH |
661 | /** |
662 | * throtl_schedule_next_dispatch - schedule the next dispatch cycle | |
663 | * @sq: the service_queue to schedule dispatch for | |
664 | * @force: force scheduling | |
665 | * | |
666 | * Arm @sq->pending_timer so that the next dispatch cycle starts on the | |
667 | * dispatch time of the first pending child. Returns %true if either timer | |
668 | * is armed or there's no pending child left. %false if the current | |
669 | * dispatch window is still open and the caller should continue | |
670 | * dispatching. | |
671 | * | |
672 | * If @force is %true, the dispatch timer is always scheduled and this | |
673 | * function is guaranteed to return %true. This is to be used when the | |
674 | * caller can't dispatch itself and needs to invoke pending_timer | |
675 | * unconditionally. Note that forced scheduling is likely to induce short | |
676 | * delay before dispatch starts even if @sq->first_pending_disptime is not | |
677 | * in the future and thus shouldn't be used in hot paths. | |
678 | */ | |
679 | static bool throtl_schedule_next_dispatch(struct throtl_service_queue *sq, | |
680 | bool force) | |
e43473b7 | 681 | { |
6a525600 | 682 | /* any pending children left? */ |
c9e0332e | 683 | if (!sq->nr_pending) |
7f52f98c | 684 | return true; |
e43473b7 | 685 | |
c9e0332e | 686 | update_min_dispatch_time(sq); |
e43473b7 | 687 | |
69df0ab0 | 688 | /* is the next dispatch time in the future? */ |
7f52f98c | 689 | if (force || time_after(sq->first_pending_disptime, jiffies)) { |
69df0ab0 | 690 | throtl_schedule_pending_timer(sq, sq->first_pending_disptime); |
7f52f98c | 691 | return true; |
69df0ab0 TH |
692 | } |
693 | ||
7f52f98c TH |
694 | /* tell the caller to continue dispatching */ |
695 | return false; | |
e43473b7 VG |
696 | } |
697 | ||
32ee5bc4 VG |
698 | static inline void throtl_start_new_slice_with_credit(struct throtl_grp *tg, |
699 | bool rw, unsigned long start) | |
700 | { | |
701 | tg->bytes_disp[rw] = 0; | |
702 | tg->io_disp[rw] = 0; | |
703 | ||
704 | /* | |
705 | * Previous slice has expired. We must have trimmed it after last | |
706 | * bio dispatch. That means since start of last slice, we never used | |
707 | * that bandwidth. Do try to make use of that bandwidth while giving | |
708 | * credit. | |
709 | */ | |
710 | if (time_after_eq(start, tg->slice_start[rw])) | |
711 | tg->slice_start[rw] = start; | |
712 | ||
297e3d85 | 713 | tg->slice_end[rw] = jiffies + tg->td->throtl_slice; |
32ee5bc4 VG |
714 | throtl_log(&tg->service_queue, |
715 | "[%c] new slice with credit start=%lu end=%lu jiffies=%lu", | |
716 | rw == READ ? 'R' : 'W', tg->slice_start[rw], | |
717 | tg->slice_end[rw], jiffies); | |
718 | } | |
719 | ||
0f3457f6 | 720 | static inline void throtl_start_new_slice(struct throtl_grp *tg, bool rw) |
e43473b7 VG |
721 | { |
722 | tg->bytes_disp[rw] = 0; | |
8e89d13f | 723 | tg->io_disp[rw] = 0; |
e43473b7 | 724 | tg->slice_start[rw] = jiffies; |
297e3d85 | 725 | tg->slice_end[rw] = jiffies + tg->td->throtl_slice; |
fda6f272 TH |
726 | throtl_log(&tg->service_queue, |
727 | "[%c] new slice start=%lu end=%lu jiffies=%lu", | |
728 | rw == READ ? 'R' : 'W', tg->slice_start[rw], | |
729 | tg->slice_end[rw], jiffies); | |
e43473b7 VG |
730 | } |
731 | ||
0f3457f6 TH |
732 | static inline void throtl_set_slice_end(struct throtl_grp *tg, bool rw, |
733 | unsigned long jiffy_end) | |
d1ae8ffd | 734 | { |
297e3d85 | 735 | tg->slice_end[rw] = roundup(jiffy_end, tg->td->throtl_slice); |
d1ae8ffd VG |
736 | } |
737 | ||
0f3457f6 TH |
738 | static inline void throtl_extend_slice(struct throtl_grp *tg, bool rw, |
739 | unsigned long jiffy_end) | |
e43473b7 | 740 | { |
297e3d85 | 741 | tg->slice_end[rw] = roundup(jiffy_end, tg->td->throtl_slice); |
fda6f272 TH |
742 | throtl_log(&tg->service_queue, |
743 | "[%c] extend slice start=%lu end=%lu jiffies=%lu", | |
744 | rw == READ ? 'R' : 'W', tg->slice_start[rw], | |
745 | tg->slice_end[rw], jiffies); | |
e43473b7 VG |
746 | } |
747 | ||
748 | /* Determine if previously allocated or extended slice is complete or not */ | |
0f3457f6 | 749 | static bool throtl_slice_used(struct throtl_grp *tg, bool rw) |
e43473b7 VG |
750 | { |
751 | if (time_in_range(jiffies, tg->slice_start[rw], tg->slice_end[rw])) | |
5cf8c227 | 752 | return false; |
e43473b7 VG |
753 | |
754 | return 1; | |
755 | } | |
756 | ||
757 | /* Trim the used slices and adjust slice start accordingly */ | |
0f3457f6 | 758 | static inline void throtl_trim_slice(struct throtl_grp *tg, bool rw) |
e43473b7 | 759 | { |
3aad5d3e VG |
760 | unsigned long nr_slices, time_elapsed, io_trim; |
761 | u64 bytes_trim, tmp; | |
e43473b7 VG |
762 | |
763 | BUG_ON(time_before(tg->slice_end[rw], tg->slice_start[rw])); | |
764 | ||
765 | /* | |
766 | * If bps are unlimited (-1), then time slice don't get | |
767 | * renewed. Don't try to trim the slice if slice is used. A new | |
768 | * slice will start when appropriate. | |
769 | */ | |
0f3457f6 | 770 | if (throtl_slice_used(tg, rw)) |
e43473b7 VG |
771 | return; |
772 | ||
d1ae8ffd VG |
773 | /* |
774 | * A bio has been dispatched. Also adjust slice_end. It might happen | |
775 | * that initially cgroup limit was very low resulting in high | |
776 | * slice_end, but later limit was bumped up and bio was dispached | |
777 | * sooner, then we need to reduce slice_end. A high bogus slice_end | |
778 | * is bad because it does not allow new slice to start. | |
779 | */ | |
780 | ||
297e3d85 | 781 | throtl_set_slice_end(tg, rw, jiffies + tg->td->throtl_slice); |
d1ae8ffd | 782 | |
e43473b7 VG |
783 | time_elapsed = jiffies - tg->slice_start[rw]; |
784 | ||
297e3d85 | 785 | nr_slices = time_elapsed / tg->td->throtl_slice; |
e43473b7 VG |
786 | |
787 | if (!nr_slices) | |
788 | return; | |
297e3d85 | 789 | tmp = tg_bps_limit(tg, rw) * tg->td->throtl_slice * nr_slices; |
3aad5d3e VG |
790 | do_div(tmp, HZ); |
791 | bytes_trim = tmp; | |
e43473b7 | 792 | |
297e3d85 SL |
793 | io_trim = (tg_iops_limit(tg, rw) * tg->td->throtl_slice * nr_slices) / |
794 | HZ; | |
e43473b7 | 795 | |
8e89d13f | 796 | if (!bytes_trim && !io_trim) |
e43473b7 VG |
797 | return; |
798 | ||
799 | if (tg->bytes_disp[rw] >= bytes_trim) | |
800 | tg->bytes_disp[rw] -= bytes_trim; | |
801 | else | |
802 | tg->bytes_disp[rw] = 0; | |
803 | ||
8e89d13f VG |
804 | if (tg->io_disp[rw] >= io_trim) |
805 | tg->io_disp[rw] -= io_trim; | |
806 | else | |
807 | tg->io_disp[rw] = 0; | |
808 | ||
297e3d85 | 809 | tg->slice_start[rw] += nr_slices * tg->td->throtl_slice; |
e43473b7 | 810 | |
fda6f272 TH |
811 | throtl_log(&tg->service_queue, |
812 | "[%c] trim slice nr=%lu bytes=%llu io=%lu start=%lu end=%lu jiffies=%lu", | |
813 | rw == READ ? 'R' : 'W', nr_slices, bytes_trim, io_trim, | |
814 | tg->slice_start[rw], tg->slice_end[rw], jiffies); | |
e43473b7 VG |
815 | } |
816 | ||
0f3457f6 TH |
817 | static bool tg_with_in_iops_limit(struct throtl_grp *tg, struct bio *bio, |
818 | unsigned long *wait) | |
e43473b7 VG |
819 | { |
820 | bool rw = bio_data_dir(bio); | |
8e89d13f | 821 | unsigned int io_allowed; |
e43473b7 | 822 | unsigned long jiffy_elapsed, jiffy_wait, jiffy_elapsed_rnd; |
c49c06e4 | 823 | u64 tmp; |
e43473b7 | 824 | |
8e89d13f | 825 | jiffy_elapsed = jiffy_elapsed_rnd = jiffies - tg->slice_start[rw]; |
e43473b7 | 826 | |
8e89d13f VG |
827 | /* Slice has just started. Consider one slice interval */ |
828 | if (!jiffy_elapsed) | |
297e3d85 | 829 | jiffy_elapsed_rnd = tg->td->throtl_slice; |
8e89d13f | 830 | |
297e3d85 | 831 | jiffy_elapsed_rnd = roundup(jiffy_elapsed_rnd, tg->td->throtl_slice); |
8e89d13f | 832 | |
c49c06e4 VG |
833 | /* |
834 | * jiffy_elapsed_rnd should not be a big value as minimum iops can be | |
835 | * 1 then at max jiffy elapsed should be equivalent of 1 second as we | |
836 | * will allow dispatch after 1 second and after that slice should | |
837 | * have been trimmed. | |
838 | */ | |
839 | ||
9f626e37 | 840 | tmp = (u64)tg_iops_limit(tg, rw) * jiffy_elapsed_rnd; |
c49c06e4 VG |
841 | do_div(tmp, HZ); |
842 | ||
843 | if (tmp > UINT_MAX) | |
844 | io_allowed = UINT_MAX; | |
845 | else | |
846 | io_allowed = tmp; | |
8e89d13f VG |
847 | |
848 | if (tg->io_disp[rw] + 1 <= io_allowed) { | |
e43473b7 VG |
849 | if (wait) |
850 | *wait = 0; | |
5cf8c227 | 851 | return true; |
e43473b7 VG |
852 | } |
853 | ||
8e89d13f | 854 | /* Calc approx time to dispatch */ |
9f626e37 | 855 | jiffy_wait = ((tg->io_disp[rw] + 1) * HZ) / tg_iops_limit(tg, rw) + 1; |
8e89d13f VG |
856 | |
857 | if (jiffy_wait > jiffy_elapsed) | |
858 | jiffy_wait = jiffy_wait - jiffy_elapsed; | |
859 | else | |
860 | jiffy_wait = 1; | |
861 | ||
862 | if (wait) | |
863 | *wait = jiffy_wait; | |
864 | return 0; | |
865 | } | |
866 | ||
0f3457f6 TH |
867 | static bool tg_with_in_bps_limit(struct throtl_grp *tg, struct bio *bio, |
868 | unsigned long *wait) | |
8e89d13f VG |
869 | { |
870 | bool rw = bio_data_dir(bio); | |
3aad5d3e | 871 | u64 bytes_allowed, extra_bytes, tmp; |
8e89d13f | 872 | unsigned long jiffy_elapsed, jiffy_wait, jiffy_elapsed_rnd; |
e43473b7 VG |
873 | |
874 | jiffy_elapsed = jiffy_elapsed_rnd = jiffies - tg->slice_start[rw]; | |
875 | ||
876 | /* Slice has just started. Consider one slice interval */ | |
877 | if (!jiffy_elapsed) | |
297e3d85 | 878 | jiffy_elapsed_rnd = tg->td->throtl_slice; |
e43473b7 | 879 | |
297e3d85 | 880 | jiffy_elapsed_rnd = roundup(jiffy_elapsed_rnd, tg->td->throtl_slice); |
e43473b7 | 881 | |
9f626e37 | 882 | tmp = tg_bps_limit(tg, rw) * jiffy_elapsed_rnd; |
5e901a2b | 883 | do_div(tmp, HZ); |
3aad5d3e | 884 | bytes_allowed = tmp; |
e43473b7 | 885 | |
4f024f37 | 886 | if (tg->bytes_disp[rw] + bio->bi_iter.bi_size <= bytes_allowed) { |
e43473b7 VG |
887 | if (wait) |
888 | *wait = 0; | |
5cf8c227 | 889 | return true; |
e43473b7 VG |
890 | } |
891 | ||
892 | /* Calc approx time to dispatch */ | |
4f024f37 | 893 | extra_bytes = tg->bytes_disp[rw] + bio->bi_iter.bi_size - bytes_allowed; |
9f626e37 | 894 | jiffy_wait = div64_u64(extra_bytes * HZ, tg_bps_limit(tg, rw)); |
e43473b7 VG |
895 | |
896 | if (!jiffy_wait) | |
897 | jiffy_wait = 1; | |
898 | ||
899 | /* | |
900 | * This wait time is without taking into consideration the rounding | |
901 | * up we did. Add that time also. | |
902 | */ | |
903 | jiffy_wait = jiffy_wait + (jiffy_elapsed_rnd - jiffy_elapsed); | |
e43473b7 VG |
904 | if (wait) |
905 | *wait = jiffy_wait; | |
8e89d13f VG |
906 | return 0; |
907 | } | |
908 | ||
909 | /* | |
910 | * Returns whether one can dispatch a bio or not. Also returns approx number | |
911 | * of jiffies to wait before this bio is with-in IO rate and can be dispatched | |
912 | */ | |
0f3457f6 TH |
913 | static bool tg_may_dispatch(struct throtl_grp *tg, struct bio *bio, |
914 | unsigned long *wait) | |
8e89d13f VG |
915 | { |
916 | bool rw = bio_data_dir(bio); | |
917 | unsigned long bps_wait = 0, iops_wait = 0, max_wait = 0; | |
918 | ||
919 | /* | |
920 | * Currently whole state machine of group depends on first bio | |
921 | * queued in the group bio list. So one should not be calling | |
922 | * this function with a different bio if there are other bios | |
923 | * queued. | |
924 | */ | |
73f0d49a | 925 | BUG_ON(tg->service_queue.nr_queued[rw] && |
c5cc2070 | 926 | bio != throtl_peek_queued(&tg->service_queue.queued[rw])); |
e43473b7 | 927 | |
8e89d13f | 928 | /* If tg->bps = -1, then BW is unlimited */ |
9f626e37 SL |
929 | if (tg_bps_limit(tg, rw) == U64_MAX && |
930 | tg_iops_limit(tg, rw) == UINT_MAX) { | |
8e89d13f VG |
931 | if (wait) |
932 | *wait = 0; | |
5cf8c227 | 933 | return true; |
8e89d13f VG |
934 | } |
935 | ||
936 | /* | |
937 | * If previous slice expired, start a new one otherwise renew/extend | |
938 | * existing slice to make sure it is at least throtl_slice interval | |
164c80ed VG |
939 | * long since now. New slice is started only for empty throttle group. |
940 | * If there is queued bio, that means there should be an active | |
941 | * slice and it should be extended instead. | |
8e89d13f | 942 | */ |
164c80ed | 943 | if (throtl_slice_used(tg, rw) && !(tg->service_queue.nr_queued[rw])) |
0f3457f6 | 944 | throtl_start_new_slice(tg, rw); |
8e89d13f | 945 | else { |
297e3d85 SL |
946 | if (time_before(tg->slice_end[rw], |
947 | jiffies + tg->td->throtl_slice)) | |
948 | throtl_extend_slice(tg, rw, | |
949 | jiffies + tg->td->throtl_slice); | |
8e89d13f VG |
950 | } |
951 | ||
0f3457f6 TH |
952 | if (tg_with_in_bps_limit(tg, bio, &bps_wait) && |
953 | tg_with_in_iops_limit(tg, bio, &iops_wait)) { | |
8e89d13f VG |
954 | if (wait) |
955 | *wait = 0; | |
956 | return 1; | |
957 | } | |
958 | ||
959 | max_wait = max(bps_wait, iops_wait); | |
960 | ||
961 | if (wait) | |
962 | *wait = max_wait; | |
963 | ||
964 | if (time_before(tg->slice_end[rw], jiffies + max_wait)) | |
0f3457f6 | 965 | throtl_extend_slice(tg, rw, jiffies + max_wait); |
e43473b7 VG |
966 | |
967 | return 0; | |
968 | } | |
969 | ||
970 | static void throtl_charge_bio(struct throtl_grp *tg, struct bio *bio) | |
971 | { | |
972 | bool rw = bio_data_dir(bio); | |
e43473b7 VG |
973 | |
974 | /* Charge the bio to the group */ | |
4f024f37 | 975 | tg->bytes_disp[rw] += bio->bi_iter.bi_size; |
8e89d13f | 976 | tg->io_disp[rw]++; |
3f0abd80 SL |
977 | tg->last_bytes_disp[rw] += bio->bi_iter.bi_size; |
978 | tg->last_io_disp[rw]++; | |
e43473b7 | 979 | |
2a0f61e6 | 980 | /* |
8d2bbd4c | 981 | * BIO_THROTTLED is used to prevent the same bio to be throttled |
2a0f61e6 TH |
982 | * more than once as a throttled bio will go through blk-throtl the |
983 | * second time when it eventually gets issued. Set it when a bio | |
984 | * is being charged to a tg. | |
2a0f61e6 | 985 | */ |
8d2bbd4c CH |
986 | if (!bio_flagged(bio, BIO_THROTTLED)) |
987 | bio_set_flag(bio, BIO_THROTTLED); | |
e43473b7 VG |
988 | } |
989 | ||
c5cc2070 TH |
990 | /** |
991 | * throtl_add_bio_tg - add a bio to the specified throtl_grp | |
992 | * @bio: bio to add | |
993 | * @qn: qnode to use | |
994 | * @tg: the target throtl_grp | |
995 | * | |
996 | * Add @bio to @tg's service_queue using @qn. If @qn is not specified, | |
997 | * tg->qnode_on_self[] is used. | |
998 | */ | |
999 | static void throtl_add_bio_tg(struct bio *bio, struct throtl_qnode *qn, | |
1000 | struct throtl_grp *tg) | |
e43473b7 | 1001 | { |
73f0d49a | 1002 | struct throtl_service_queue *sq = &tg->service_queue; |
e43473b7 VG |
1003 | bool rw = bio_data_dir(bio); |
1004 | ||
c5cc2070 TH |
1005 | if (!qn) |
1006 | qn = &tg->qnode_on_self[rw]; | |
1007 | ||
0e9f4164 TH |
1008 | /* |
1009 | * If @tg doesn't currently have any bios queued in the same | |
1010 | * direction, queueing @bio can change when @tg should be | |
1011 | * dispatched. Mark that @tg was empty. This is automatically | |
1012 | * cleaered on the next tg_update_disptime(). | |
1013 | */ | |
1014 | if (!sq->nr_queued[rw]) | |
1015 | tg->flags |= THROTL_TG_WAS_EMPTY; | |
1016 | ||
c5cc2070 TH |
1017 | throtl_qnode_add_bio(bio, qn, &sq->queued[rw]); |
1018 | ||
73f0d49a | 1019 | sq->nr_queued[rw]++; |
77216b04 | 1020 | throtl_enqueue_tg(tg); |
e43473b7 VG |
1021 | } |
1022 | ||
77216b04 | 1023 | static void tg_update_disptime(struct throtl_grp *tg) |
e43473b7 | 1024 | { |
73f0d49a | 1025 | struct throtl_service_queue *sq = &tg->service_queue; |
e43473b7 VG |
1026 | unsigned long read_wait = -1, write_wait = -1, min_wait = -1, disptime; |
1027 | struct bio *bio; | |
1028 | ||
d609af3a ME |
1029 | bio = throtl_peek_queued(&sq->queued[READ]); |
1030 | if (bio) | |
0f3457f6 | 1031 | tg_may_dispatch(tg, bio, &read_wait); |
e43473b7 | 1032 | |
d609af3a ME |
1033 | bio = throtl_peek_queued(&sq->queued[WRITE]); |
1034 | if (bio) | |
0f3457f6 | 1035 | tg_may_dispatch(tg, bio, &write_wait); |
e43473b7 VG |
1036 | |
1037 | min_wait = min(read_wait, write_wait); | |
1038 | disptime = jiffies + min_wait; | |
1039 | ||
e43473b7 | 1040 | /* Update dispatch time */ |
77216b04 | 1041 | throtl_dequeue_tg(tg); |
e43473b7 | 1042 | tg->disptime = disptime; |
77216b04 | 1043 | throtl_enqueue_tg(tg); |
0e9f4164 TH |
1044 | |
1045 | /* see throtl_add_bio_tg() */ | |
1046 | tg->flags &= ~THROTL_TG_WAS_EMPTY; | |
e43473b7 VG |
1047 | } |
1048 | ||
32ee5bc4 VG |
1049 | static void start_parent_slice_with_credit(struct throtl_grp *child_tg, |
1050 | struct throtl_grp *parent_tg, bool rw) | |
1051 | { | |
1052 | if (throtl_slice_used(parent_tg, rw)) { | |
1053 | throtl_start_new_slice_with_credit(parent_tg, rw, | |
1054 | child_tg->slice_start[rw]); | |
1055 | } | |
1056 | ||
1057 | } | |
1058 | ||
77216b04 | 1059 | static void tg_dispatch_one_bio(struct throtl_grp *tg, bool rw) |
e43473b7 | 1060 | { |
73f0d49a | 1061 | struct throtl_service_queue *sq = &tg->service_queue; |
6bc9c2b4 TH |
1062 | struct throtl_service_queue *parent_sq = sq->parent_sq; |
1063 | struct throtl_grp *parent_tg = sq_to_tg(parent_sq); | |
c5cc2070 | 1064 | struct throtl_grp *tg_to_put = NULL; |
e43473b7 VG |
1065 | struct bio *bio; |
1066 | ||
c5cc2070 TH |
1067 | /* |
1068 | * @bio is being transferred from @tg to @parent_sq. Popping a bio | |
1069 | * from @tg may put its reference and @parent_sq might end up | |
1070 | * getting released prematurely. Remember the tg to put and put it | |
1071 | * after @bio is transferred to @parent_sq. | |
1072 | */ | |
1073 | bio = throtl_pop_queued(&sq->queued[rw], &tg_to_put); | |
73f0d49a | 1074 | sq->nr_queued[rw]--; |
e43473b7 VG |
1075 | |
1076 | throtl_charge_bio(tg, bio); | |
6bc9c2b4 TH |
1077 | |
1078 | /* | |
1079 | * If our parent is another tg, we just need to transfer @bio to | |
1080 | * the parent using throtl_add_bio_tg(). If our parent is | |
1081 | * @td->service_queue, @bio is ready to be issued. Put it on its | |
1082 | * bio_lists[] and decrease total number queued. The caller is | |
1083 | * responsible for issuing these bios. | |
1084 | */ | |
1085 | if (parent_tg) { | |
c5cc2070 | 1086 | throtl_add_bio_tg(bio, &tg->qnode_on_parent[rw], parent_tg); |
32ee5bc4 | 1087 | start_parent_slice_with_credit(tg, parent_tg, rw); |
6bc9c2b4 | 1088 | } else { |
c5cc2070 TH |
1089 | throtl_qnode_add_bio(bio, &tg->qnode_on_parent[rw], |
1090 | &parent_sq->queued[rw]); | |
6bc9c2b4 TH |
1091 | BUG_ON(tg->td->nr_queued[rw] <= 0); |
1092 | tg->td->nr_queued[rw]--; | |
1093 | } | |
e43473b7 | 1094 | |
0f3457f6 | 1095 | throtl_trim_slice(tg, rw); |
6bc9c2b4 | 1096 | |
c5cc2070 TH |
1097 | if (tg_to_put) |
1098 | blkg_put(tg_to_blkg(tg_to_put)); | |
e43473b7 VG |
1099 | } |
1100 | ||
77216b04 | 1101 | static int throtl_dispatch_tg(struct throtl_grp *tg) |
e43473b7 | 1102 | { |
73f0d49a | 1103 | struct throtl_service_queue *sq = &tg->service_queue; |
e43473b7 VG |
1104 | unsigned int nr_reads = 0, nr_writes = 0; |
1105 | unsigned int max_nr_reads = throtl_grp_quantum*3/4; | |
c2f6805d | 1106 | unsigned int max_nr_writes = throtl_grp_quantum - max_nr_reads; |
e43473b7 VG |
1107 | struct bio *bio; |
1108 | ||
1109 | /* Try to dispatch 75% READS and 25% WRITES */ | |
1110 | ||
c5cc2070 | 1111 | while ((bio = throtl_peek_queued(&sq->queued[READ])) && |
0f3457f6 | 1112 | tg_may_dispatch(tg, bio, NULL)) { |
e43473b7 | 1113 | |
77216b04 | 1114 | tg_dispatch_one_bio(tg, bio_data_dir(bio)); |
e43473b7 VG |
1115 | nr_reads++; |
1116 | ||
1117 | if (nr_reads >= max_nr_reads) | |
1118 | break; | |
1119 | } | |
1120 | ||
c5cc2070 | 1121 | while ((bio = throtl_peek_queued(&sq->queued[WRITE])) && |
0f3457f6 | 1122 | tg_may_dispatch(tg, bio, NULL)) { |
e43473b7 | 1123 | |
77216b04 | 1124 | tg_dispatch_one_bio(tg, bio_data_dir(bio)); |
e43473b7 VG |
1125 | nr_writes++; |
1126 | ||
1127 | if (nr_writes >= max_nr_writes) | |
1128 | break; | |
1129 | } | |
1130 | ||
1131 | return nr_reads + nr_writes; | |
1132 | } | |
1133 | ||
651930bc | 1134 | static int throtl_select_dispatch(struct throtl_service_queue *parent_sq) |
e43473b7 VG |
1135 | { |
1136 | unsigned int nr_disp = 0; | |
e43473b7 VG |
1137 | |
1138 | while (1) { | |
73f0d49a TH |
1139 | struct throtl_grp *tg = throtl_rb_first(parent_sq); |
1140 | struct throtl_service_queue *sq = &tg->service_queue; | |
e43473b7 VG |
1141 | |
1142 | if (!tg) | |
1143 | break; | |
1144 | ||
1145 | if (time_before(jiffies, tg->disptime)) | |
1146 | break; | |
1147 | ||
77216b04 | 1148 | throtl_dequeue_tg(tg); |
e43473b7 | 1149 | |
77216b04 | 1150 | nr_disp += throtl_dispatch_tg(tg); |
e43473b7 | 1151 | |
73f0d49a | 1152 | if (sq->nr_queued[0] || sq->nr_queued[1]) |
77216b04 | 1153 | tg_update_disptime(tg); |
e43473b7 VG |
1154 | |
1155 | if (nr_disp >= throtl_quantum) | |
1156 | break; | |
1157 | } | |
1158 | ||
1159 | return nr_disp; | |
1160 | } | |
1161 | ||
c79892c5 SL |
1162 | static bool throtl_can_upgrade(struct throtl_data *td, |
1163 | struct throtl_grp *this_tg); | |
6e1a5704 TH |
1164 | /** |
1165 | * throtl_pending_timer_fn - timer function for service_queue->pending_timer | |
1166 | * @arg: the throtl_service_queue being serviced | |
1167 | * | |
1168 | * This timer is armed when a child throtl_grp with active bio's become | |
1169 | * pending and queued on the service_queue's pending_tree and expires when | |
1170 | * the first child throtl_grp should be dispatched. This function | |
2e48a530 TH |
1171 | * dispatches bio's from the children throtl_grps to the parent |
1172 | * service_queue. | |
1173 | * | |
1174 | * If the parent's parent is another throtl_grp, dispatching is propagated | |
1175 | * by either arming its pending_timer or repeating dispatch directly. If | |
1176 | * the top-level service_tree is reached, throtl_data->dispatch_work is | |
1177 | * kicked so that the ready bio's are issued. | |
6e1a5704 | 1178 | */ |
69df0ab0 TH |
1179 | static void throtl_pending_timer_fn(unsigned long arg) |
1180 | { | |
1181 | struct throtl_service_queue *sq = (void *)arg; | |
2e48a530 | 1182 | struct throtl_grp *tg = sq_to_tg(sq); |
69df0ab0 | 1183 | struct throtl_data *td = sq_to_td(sq); |
cb76199c | 1184 | struct request_queue *q = td->queue; |
2e48a530 TH |
1185 | struct throtl_service_queue *parent_sq; |
1186 | bool dispatched; | |
6e1a5704 | 1187 | int ret; |
e43473b7 VG |
1188 | |
1189 | spin_lock_irq(q->queue_lock); | |
c79892c5 SL |
1190 | if (throtl_can_upgrade(td, NULL)) |
1191 | throtl_upgrade_state(td); | |
1192 | ||
2e48a530 TH |
1193 | again: |
1194 | parent_sq = sq->parent_sq; | |
1195 | dispatched = false; | |
e43473b7 | 1196 | |
7f52f98c TH |
1197 | while (true) { |
1198 | throtl_log(sq, "dispatch nr_queued=%u read=%u write=%u", | |
2e48a530 TH |
1199 | sq->nr_queued[READ] + sq->nr_queued[WRITE], |
1200 | sq->nr_queued[READ], sq->nr_queued[WRITE]); | |
7f52f98c TH |
1201 | |
1202 | ret = throtl_select_dispatch(sq); | |
1203 | if (ret) { | |
7f52f98c TH |
1204 | throtl_log(sq, "bios disp=%u", ret); |
1205 | dispatched = true; | |
1206 | } | |
e43473b7 | 1207 | |
7f52f98c TH |
1208 | if (throtl_schedule_next_dispatch(sq, false)) |
1209 | break; | |
e43473b7 | 1210 | |
7f52f98c TH |
1211 | /* this dispatch windows is still open, relax and repeat */ |
1212 | spin_unlock_irq(q->queue_lock); | |
1213 | cpu_relax(); | |
1214 | spin_lock_irq(q->queue_lock); | |
651930bc | 1215 | } |
e43473b7 | 1216 | |
2e48a530 TH |
1217 | if (!dispatched) |
1218 | goto out_unlock; | |
6e1a5704 | 1219 | |
2e48a530 TH |
1220 | if (parent_sq) { |
1221 | /* @parent_sq is another throl_grp, propagate dispatch */ | |
1222 | if (tg->flags & THROTL_TG_WAS_EMPTY) { | |
1223 | tg_update_disptime(tg); | |
1224 | if (!throtl_schedule_next_dispatch(parent_sq, false)) { | |
1225 | /* window is already open, repeat dispatching */ | |
1226 | sq = parent_sq; | |
1227 | tg = sq_to_tg(sq); | |
1228 | goto again; | |
1229 | } | |
1230 | } | |
1231 | } else { | |
1232 | /* reached the top-level, queue issueing */ | |
1233 | queue_work(kthrotld_workqueue, &td->dispatch_work); | |
1234 | } | |
1235 | out_unlock: | |
e43473b7 | 1236 | spin_unlock_irq(q->queue_lock); |
6e1a5704 | 1237 | } |
e43473b7 | 1238 | |
6e1a5704 TH |
1239 | /** |
1240 | * blk_throtl_dispatch_work_fn - work function for throtl_data->dispatch_work | |
1241 | * @work: work item being executed | |
1242 | * | |
1243 | * This function is queued for execution when bio's reach the bio_lists[] | |
1244 | * of throtl_data->service_queue. Those bio's are ready and issued by this | |
1245 | * function. | |
1246 | */ | |
8876e140 | 1247 | static void blk_throtl_dispatch_work_fn(struct work_struct *work) |
6e1a5704 TH |
1248 | { |
1249 | struct throtl_data *td = container_of(work, struct throtl_data, | |
1250 | dispatch_work); | |
1251 | struct throtl_service_queue *td_sq = &td->service_queue; | |
1252 | struct request_queue *q = td->queue; | |
1253 | struct bio_list bio_list_on_stack; | |
1254 | struct bio *bio; | |
1255 | struct blk_plug plug; | |
1256 | int rw; | |
1257 | ||
1258 | bio_list_init(&bio_list_on_stack); | |
1259 | ||
1260 | spin_lock_irq(q->queue_lock); | |
c5cc2070 TH |
1261 | for (rw = READ; rw <= WRITE; rw++) |
1262 | while ((bio = throtl_pop_queued(&td_sq->queued[rw], NULL))) | |
1263 | bio_list_add(&bio_list_on_stack, bio); | |
6e1a5704 TH |
1264 | spin_unlock_irq(q->queue_lock); |
1265 | ||
1266 | if (!bio_list_empty(&bio_list_on_stack)) { | |
69d60eb9 | 1267 | blk_start_plug(&plug); |
e43473b7 VG |
1268 | while((bio = bio_list_pop(&bio_list_on_stack))) |
1269 | generic_make_request(bio); | |
69d60eb9 | 1270 | blk_finish_plug(&plug); |
e43473b7 | 1271 | } |
e43473b7 VG |
1272 | } |
1273 | ||
f95a04af TH |
1274 | static u64 tg_prfill_conf_u64(struct seq_file *sf, struct blkg_policy_data *pd, |
1275 | int off) | |
60c2bc2d | 1276 | { |
f95a04af TH |
1277 | struct throtl_grp *tg = pd_to_tg(pd); |
1278 | u64 v = *(u64 *)((void *)tg + off); | |
60c2bc2d | 1279 | |
2ab5492d | 1280 | if (v == U64_MAX) |
60c2bc2d | 1281 | return 0; |
f95a04af | 1282 | return __blkg_prfill_u64(sf, pd, v); |
60c2bc2d TH |
1283 | } |
1284 | ||
f95a04af TH |
1285 | static u64 tg_prfill_conf_uint(struct seq_file *sf, struct blkg_policy_data *pd, |
1286 | int off) | |
e43473b7 | 1287 | { |
f95a04af TH |
1288 | struct throtl_grp *tg = pd_to_tg(pd); |
1289 | unsigned int v = *(unsigned int *)((void *)tg + off); | |
fe071437 | 1290 | |
2ab5492d | 1291 | if (v == UINT_MAX) |
af133ceb | 1292 | return 0; |
f95a04af | 1293 | return __blkg_prfill_u64(sf, pd, v); |
e43473b7 VG |
1294 | } |
1295 | ||
2da8ca82 | 1296 | static int tg_print_conf_u64(struct seq_file *sf, void *v) |
8e89d13f | 1297 | { |
2da8ca82 TH |
1298 | blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), tg_prfill_conf_u64, |
1299 | &blkcg_policy_throtl, seq_cft(sf)->private, false); | |
af133ceb | 1300 | return 0; |
8e89d13f VG |
1301 | } |
1302 | ||
2da8ca82 | 1303 | static int tg_print_conf_uint(struct seq_file *sf, void *v) |
8e89d13f | 1304 | { |
2da8ca82 TH |
1305 | blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), tg_prfill_conf_uint, |
1306 | &blkcg_policy_throtl, seq_cft(sf)->private, false); | |
af133ceb | 1307 | return 0; |
60c2bc2d TH |
1308 | } |
1309 | ||
69948b07 | 1310 | static void tg_conf_updated(struct throtl_grp *tg) |
60c2bc2d | 1311 | { |
69948b07 | 1312 | struct throtl_service_queue *sq = &tg->service_queue; |
492eb21b | 1313 | struct cgroup_subsys_state *pos_css; |
69948b07 | 1314 | struct blkcg_gq *blkg; |
af133ceb | 1315 | |
fda6f272 TH |
1316 | throtl_log(&tg->service_queue, |
1317 | "limit change rbps=%llu wbps=%llu riops=%u wiops=%u", | |
9f626e37 SL |
1318 | tg_bps_limit(tg, READ), tg_bps_limit(tg, WRITE), |
1319 | tg_iops_limit(tg, READ), tg_iops_limit(tg, WRITE)); | |
632b4493 | 1320 | |
693e751e TH |
1321 | /* |
1322 | * Update has_rules[] flags for the updated tg's subtree. A tg is | |
1323 | * considered to have rules if either the tg itself or any of its | |
1324 | * ancestors has rules. This identifies groups without any | |
1325 | * restrictions in the whole hierarchy and allows them to bypass | |
1326 | * blk-throttle. | |
1327 | */ | |
69948b07 | 1328 | blkg_for_each_descendant_pre(blkg, pos_css, tg_to_blkg(tg)) |
693e751e TH |
1329 | tg_update_has_rules(blkg_to_tg(blkg)); |
1330 | ||
632b4493 TH |
1331 | /* |
1332 | * We're already holding queue_lock and know @tg is valid. Let's | |
1333 | * apply the new config directly. | |
1334 | * | |
1335 | * Restart the slices for both READ and WRITES. It might happen | |
1336 | * that a group's limit are dropped suddenly and we don't want to | |
1337 | * account recently dispatched IO with new low rate. | |
1338 | */ | |
0f3457f6 TH |
1339 | throtl_start_new_slice(tg, 0); |
1340 | throtl_start_new_slice(tg, 1); | |
632b4493 | 1341 | |
5b2c16aa | 1342 | if (tg->flags & THROTL_TG_PENDING) { |
77216b04 | 1343 | tg_update_disptime(tg); |
7f52f98c | 1344 | throtl_schedule_next_dispatch(sq->parent_sq, true); |
632b4493 | 1345 | } |
69948b07 TH |
1346 | } |
1347 | ||
1348 | static ssize_t tg_set_conf(struct kernfs_open_file *of, | |
1349 | char *buf, size_t nbytes, loff_t off, bool is_u64) | |
1350 | { | |
1351 | struct blkcg *blkcg = css_to_blkcg(of_css(of)); | |
1352 | struct blkg_conf_ctx ctx; | |
1353 | struct throtl_grp *tg; | |
1354 | int ret; | |
1355 | u64 v; | |
1356 | ||
1357 | ret = blkg_conf_prep(blkcg, &blkcg_policy_throtl, buf, &ctx); | |
1358 | if (ret) | |
1359 | return ret; | |
1360 | ||
1361 | ret = -EINVAL; | |
1362 | if (sscanf(ctx.body, "%llu", &v) != 1) | |
1363 | goto out_finish; | |
1364 | if (!v) | |
2ab5492d | 1365 | v = U64_MAX; |
69948b07 TH |
1366 | |
1367 | tg = blkg_to_tg(ctx.blkg); | |
1368 | ||
1369 | if (is_u64) | |
1370 | *(u64 *)((void *)tg + of_cft(of)->private) = v; | |
1371 | else | |
1372 | *(unsigned int *)((void *)tg + of_cft(of)->private) = v; | |
60c2bc2d | 1373 | |
69948b07 | 1374 | tg_conf_updated(tg); |
36aa9e5f TH |
1375 | ret = 0; |
1376 | out_finish: | |
60c2bc2d | 1377 | blkg_conf_finish(&ctx); |
36aa9e5f | 1378 | return ret ?: nbytes; |
8e89d13f VG |
1379 | } |
1380 | ||
451af504 TH |
1381 | static ssize_t tg_set_conf_u64(struct kernfs_open_file *of, |
1382 | char *buf, size_t nbytes, loff_t off) | |
60c2bc2d | 1383 | { |
451af504 | 1384 | return tg_set_conf(of, buf, nbytes, off, true); |
60c2bc2d TH |
1385 | } |
1386 | ||
451af504 TH |
1387 | static ssize_t tg_set_conf_uint(struct kernfs_open_file *of, |
1388 | char *buf, size_t nbytes, loff_t off) | |
60c2bc2d | 1389 | { |
451af504 | 1390 | return tg_set_conf(of, buf, nbytes, off, false); |
60c2bc2d TH |
1391 | } |
1392 | ||
880f50e2 | 1393 | static struct cftype throtl_legacy_files[] = { |
60c2bc2d TH |
1394 | { |
1395 | .name = "throttle.read_bps_device", | |
9f626e37 | 1396 | .private = offsetof(struct throtl_grp, bps[READ][LIMIT_MAX]), |
2da8ca82 | 1397 | .seq_show = tg_print_conf_u64, |
451af504 | 1398 | .write = tg_set_conf_u64, |
60c2bc2d TH |
1399 | }, |
1400 | { | |
1401 | .name = "throttle.write_bps_device", | |
9f626e37 | 1402 | .private = offsetof(struct throtl_grp, bps[WRITE][LIMIT_MAX]), |
2da8ca82 | 1403 | .seq_show = tg_print_conf_u64, |
451af504 | 1404 | .write = tg_set_conf_u64, |
60c2bc2d TH |
1405 | }, |
1406 | { | |
1407 | .name = "throttle.read_iops_device", | |
9f626e37 | 1408 | .private = offsetof(struct throtl_grp, iops[READ][LIMIT_MAX]), |
2da8ca82 | 1409 | .seq_show = tg_print_conf_uint, |
451af504 | 1410 | .write = tg_set_conf_uint, |
60c2bc2d TH |
1411 | }, |
1412 | { | |
1413 | .name = "throttle.write_iops_device", | |
9f626e37 | 1414 | .private = offsetof(struct throtl_grp, iops[WRITE][LIMIT_MAX]), |
2da8ca82 | 1415 | .seq_show = tg_print_conf_uint, |
451af504 | 1416 | .write = tg_set_conf_uint, |
60c2bc2d TH |
1417 | }, |
1418 | { | |
1419 | .name = "throttle.io_service_bytes", | |
77ea7338 TH |
1420 | .private = (unsigned long)&blkcg_policy_throtl, |
1421 | .seq_show = blkg_print_stat_bytes, | |
60c2bc2d TH |
1422 | }, |
1423 | { | |
1424 | .name = "throttle.io_serviced", | |
77ea7338 TH |
1425 | .private = (unsigned long)&blkcg_policy_throtl, |
1426 | .seq_show = blkg_print_stat_ios, | |
60c2bc2d TH |
1427 | }, |
1428 | { } /* terminate */ | |
1429 | }; | |
1430 | ||
cd5ab1b0 | 1431 | static u64 tg_prfill_limit(struct seq_file *sf, struct blkg_policy_data *pd, |
2ee867dc TH |
1432 | int off) |
1433 | { | |
1434 | struct throtl_grp *tg = pd_to_tg(pd); | |
1435 | const char *dname = blkg_dev_name(pd->blkg); | |
1436 | char bufs[4][21] = { "max", "max", "max", "max" }; | |
cd5ab1b0 SL |
1437 | u64 bps_dft; |
1438 | unsigned int iops_dft; | |
2ee867dc TH |
1439 | |
1440 | if (!dname) | |
1441 | return 0; | |
9f626e37 | 1442 | |
cd5ab1b0 SL |
1443 | if (off == LIMIT_LOW) { |
1444 | bps_dft = 0; | |
1445 | iops_dft = 0; | |
1446 | } else { | |
1447 | bps_dft = U64_MAX; | |
1448 | iops_dft = UINT_MAX; | |
1449 | } | |
1450 | ||
1451 | if (tg->bps_conf[READ][off] == bps_dft && | |
1452 | tg->bps_conf[WRITE][off] == bps_dft && | |
1453 | tg->iops_conf[READ][off] == iops_dft && | |
1454 | tg->iops_conf[WRITE][off] == iops_dft) | |
2ee867dc TH |
1455 | return 0; |
1456 | ||
cd5ab1b0 | 1457 | if (tg->bps_conf[READ][off] != bps_dft) |
9f626e37 | 1458 | snprintf(bufs[0], sizeof(bufs[0]), "%llu", |
cd5ab1b0 SL |
1459 | tg->bps_conf[READ][off]); |
1460 | if (tg->bps_conf[WRITE][off] != bps_dft) | |
9f626e37 | 1461 | snprintf(bufs[1], sizeof(bufs[1]), "%llu", |
cd5ab1b0 SL |
1462 | tg->bps_conf[WRITE][off]); |
1463 | if (tg->iops_conf[READ][off] != iops_dft) | |
9f626e37 | 1464 | snprintf(bufs[2], sizeof(bufs[2]), "%u", |
cd5ab1b0 SL |
1465 | tg->iops_conf[READ][off]); |
1466 | if (tg->iops_conf[WRITE][off] != iops_dft) | |
9f626e37 | 1467 | snprintf(bufs[3], sizeof(bufs[3]), "%u", |
cd5ab1b0 | 1468 | tg->iops_conf[WRITE][off]); |
2ee867dc TH |
1469 | |
1470 | seq_printf(sf, "%s rbps=%s wbps=%s riops=%s wiops=%s\n", | |
1471 | dname, bufs[0], bufs[1], bufs[2], bufs[3]); | |
1472 | return 0; | |
1473 | } | |
1474 | ||
cd5ab1b0 | 1475 | static int tg_print_limit(struct seq_file *sf, void *v) |
2ee867dc | 1476 | { |
cd5ab1b0 | 1477 | blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), tg_prfill_limit, |
2ee867dc TH |
1478 | &blkcg_policy_throtl, seq_cft(sf)->private, false); |
1479 | return 0; | |
1480 | } | |
1481 | ||
cd5ab1b0 | 1482 | static ssize_t tg_set_limit(struct kernfs_open_file *of, |
2ee867dc TH |
1483 | char *buf, size_t nbytes, loff_t off) |
1484 | { | |
1485 | struct blkcg *blkcg = css_to_blkcg(of_css(of)); | |
1486 | struct blkg_conf_ctx ctx; | |
1487 | struct throtl_grp *tg; | |
1488 | u64 v[4]; | |
1489 | int ret; | |
cd5ab1b0 | 1490 | int index = of_cft(of)->private; |
2ee867dc TH |
1491 | |
1492 | ret = blkg_conf_prep(blkcg, &blkcg_policy_throtl, buf, &ctx); | |
1493 | if (ret) | |
1494 | return ret; | |
1495 | ||
1496 | tg = blkg_to_tg(ctx.blkg); | |
1497 | ||
cd5ab1b0 SL |
1498 | v[0] = tg->bps_conf[READ][index]; |
1499 | v[1] = tg->bps_conf[WRITE][index]; | |
1500 | v[2] = tg->iops_conf[READ][index]; | |
1501 | v[3] = tg->iops_conf[WRITE][index]; | |
2ee867dc TH |
1502 | |
1503 | while (true) { | |
1504 | char tok[27]; /* wiops=18446744073709551616 */ | |
1505 | char *p; | |
2ab5492d | 1506 | u64 val = U64_MAX; |
2ee867dc TH |
1507 | int len; |
1508 | ||
1509 | if (sscanf(ctx.body, "%26s%n", tok, &len) != 1) | |
1510 | break; | |
1511 | if (tok[0] == '\0') | |
1512 | break; | |
1513 | ctx.body += len; | |
1514 | ||
1515 | ret = -EINVAL; | |
1516 | p = tok; | |
1517 | strsep(&p, "="); | |
1518 | if (!p || (sscanf(p, "%llu", &val) != 1 && strcmp(p, "max"))) | |
1519 | goto out_finish; | |
1520 | ||
1521 | ret = -ERANGE; | |
1522 | if (!val) | |
1523 | goto out_finish; | |
1524 | ||
1525 | ret = -EINVAL; | |
1526 | if (!strcmp(tok, "rbps")) | |
1527 | v[0] = val; | |
1528 | else if (!strcmp(tok, "wbps")) | |
1529 | v[1] = val; | |
1530 | else if (!strcmp(tok, "riops")) | |
1531 | v[2] = min_t(u64, val, UINT_MAX); | |
1532 | else if (!strcmp(tok, "wiops")) | |
1533 | v[3] = min_t(u64, val, UINT_MAX); | |
1534 | else | |
1535 | goto out_finish; | |
1536 | } | |
1537 | ||
cd5ab1b0 SL |
1538 | tg->bps_conf[READ][index] = v[0]; |
1539 | tg->bps_conf[WRITE][index] = v[1]; | |
1540 | tg->iops_conf[READ][index] = v[2]; | |
1541 | tg->iops_conf[WRITE][index] = v[3]; | |
2ee867dc | 1542 | |
cd5ab1b0 SL |
1543 | if (index == LIMIT_MAX) { |
1544 | tg->bps[READ][index] = v[0]; | |
1545 | tg->bps[WRITE][index] = v[1]; | |
1546 | tg->iops[READ][index] = v[2]; | |
1547 | tg->iops[WRITE][index] = v[3]; | |
1548 | } | |
1549 | tg->bps[READ][LIMIT_LOW] = min(tg->bps_conf[READ][LIMIT_LOW], | |
1550 | tg->bps_conf[READ][LIMIT_MAX]); | |
1551 | tg->bps[WRITE][LIMIT_LOW] = min(tg->bps_conf[WRITE][LIMIT_LOW], | |
1552 | tg->bps_conf[WRITE][LIMIT_MAX]); | |
1553 | tg->iops[READ][LIMIT_LOW] = min(tg->iops_conf[READ][LIMIT_LOW], | |
1554 | tg->iops_conf[READ][LIMIT_MAX]); | |
1555 | tg->iops[WRITE][LIMIT_LOW] = min(tg->iops_conf[WRITE][LIMIT_LOW], | |
1556 | tg->iops_conf[WRITE][LIMIT_MAX]); | |
1557 | ||
1558 | if (index == LIMIT_LOW) { | |
1559 | blk_throtl_update_limit_valid(tg->td); | |
1560 | if (tg->td->limit_valid[LIMIT_LOW]) | |
1561 | tg->td->limit_index = LIMIT_LOW; | |
1562 | } | |
2ee867dc TH |
1563 | tg_conf_updated(tg); |
1564 | ret = 0; | |
1565 | out_finish: | |
1566 | blkg_conf_finish(&ctx); | |
1567 | return ret ?: nbytes; | |
1568 | } | |
1569 | ||
1570 | static struct cftype throtl_files[] = { | |
cd5ab1b0 SL |
1571 | #ifdef CONFIG_BLK_DEV_THROTTLING_LOW |
1572 | { | |
1573 | .name = "low", | |
1574 | .flags = CFTYPE_NOT_ON_ROOT, | |
1575 | .seq_show = tg_print_limit, | |
1576 | .write = tg_set_limit, | |
1577 | .private = LIMIT_LOW, | |
1578 | }, | |
1579 | #endif | |
2ee867dc TH |
1580 | { |
1581 | .name = "max", | |
1582 | .flags = CFTYPE_NOT_ON_ROOT, | |
cd5ab1b0 SL |
1583 | .seq_show = tg_print_limit, |
1584 | .write = tg_set_limit, | |
1585 | .private = LIMIT_MAX, | |
2ee867dc TH |
1586 | }, |
1587 | { } /* terminate */ | |
1588 | }; | |
1589 | ||
da527770 | 1590 | static void throtl_shutdown_wq(struct request_queue *q) |
e43473b7 VG |
1591 | { |
1592 | struct throtl_data *td = q->td; | |
1593 | ||
69df0ab0 | 1594 | cancel_work_sync(&td->dispatch_work); |
e43473b7 VG |
1595 | } |
1596 | ||
3c798398 | 1597 | static struct blkcg_policy blkcg_policy_throtl = { |
2ee867dc | 1598 | .dfl_cftypes = throtl_files, |
880f50e2 | 1599 | .legacy_cftypes = throtl_legacy_files, |
f9fcc2d3 | 1600 | |
001bea73 | 1601 | .pd_alloc_fn = throtl_pd_alloc, |
f9fcc2d3 | 1602 | .pd_init_fn = throtl_pd_init, |
693e751e | 1603 | .pd_online_fn = throtl_pd_online, |
cd5ab1b0 | 1604 | .pd_offline_fn = throtl_pd_offline, |
001bea73 | 1605 | .pd_free_fn = throtl_pd_free, |
e43473b7 VG |
1606 | }; |
1607 | ||
3f0abd80 SL |
1608 | static unsigned long __tg_last_low_overflow_time(struct throtl_grp *tg) |
1609 | { | |
1610 | unsigned long rtime = jiffies, wtime = jiffies; | |
1611 | ||
1612 | if (tg->bps[READ][LIMIT_LOW] || tg->iops[READ][LIMIT_LOW]) | |
1613 | rtime = tg->last_low_overflow_time[READ]; | |
1614 | if (tg->bps[WRITE][LIMIT_LOW] || tg->iops[WRITE][LIMIT_LOW]) | |
1615 | wtime = tg->last_low_overflow_time[WRITE]; | |
1616 | return min(rtime, wtime); | |
1617 | } | |
1618 | ||
1619 | /* tg should not be an intermediate node */ | |
1620 | static unsigned long tg_last_low_overflow_time(struct throtl_grp *tg) | |
1621 | { | |
1622 | struct throtl_service_queue *parent_sq; | |
1623 | struct throtl_grp *parent = tg; | |
1624 | unsigned long ret = __tg_last_low_overflow_time(tg); | |
1625 | ||
1626 | while (true) { | |
1627 | parent_sq = parent->service_queue.parent_sq; | |
1628 | parent = sq_to_tg(parent_sq); | |
1629 | if (!parent) | |
1630 | break; | |
1631 | ||
1632 | /* | |
1633 | * The parent doesn't have low limit, it always reaches low | |
1634 | * limit. Its overflow time is useless for children | |
1635 | */ | |
1636 | if (!parent->bps[READ][LIMIT_LOW] && | |
1637 | !parent->iops[READ][LIMIT_LOW] && | |
1638 | !parent->bps[WRITE][LIMIT_LOW] && | |
1639 | !parent->iops[WRITE][LIMIT_LOW]) | |
1640 | continue; | |
1641 | if (time_after(__tg_last_low_overflow_time(parent), ret)) | |
1642 | ret = __tg_last_low_overflow_time(parent); | |
1643 | } | |
1644 | return ret; | |
1645 | } | |
1646 | ||
c79892c5 SL |
1647 | static bool throtl_tg_can_upgrade(struct throtl_grp *tg) |
1648 | { | |
1649 | struct throtl_service_queue *sq = &tg->service_queue; | |
1650 | bool read_limit, write_limit; | |
1651 | ||
1652 | /* | |
1653 | * if cgroup reaches low limit (if low limit is 0, the cgroup always | |
1654 | * reaches), it's ok to upgrade to next limit | |
1655 | */ | |
1656 | read_limit = tg->bps[READ][LIMIT_LOW] || tg->iops[READ][LIMIT_LOW]; | |
1657 | write_limit = tg->bps[WRITE][LIMIT_LOW] || tg->iops[WRITE][LIMIT_LOW]; | |
1658 | if (!read_limit && !write_limit) | |
1659 | return true; | |
1660 | if (read_limit && sq->nr_queued[READ] && | |
1661 | (!write_limit || sq->nr_queued[WRITE])) | |
1662 | return true; | |
1663 | if (write_limit && sq->nr_queued[WRITE] && | |
1664 | (!read_limit || sq->nr_queued[READ])) | |
1665 | return true; | |
aec24246 SL |
1666 | |
1667 | if (time_after_eq(jiffies, | |
1668 | tg->last_dispatch_time[READ] + tg->td->throtl_slice) && | |
1669 | time_after_eq(jiffies, | |
1670 | tg->last_dispatch_time[WRITE] + tg->td->throtl_slice)) | |
1671 | return true; | |
c79892c5 SL |
1672 | return false; |
1673 | } | |
1674 | ||
1675 | static bool throtl_hierarchy_can_upgrade(struct throtl_grp *tg) | |
1676 | { | |
1677 | while (true) { | |
1678 | if (throtl_tg_can_upgrade(tg)) | |
1679 | return true; | |
1680 | tg = sq_to_tg(tg->service_queue.parent_sq); | |
1681 | if (!tg || !tg_to_blkg(tg)->parent) | |
1682 | return false; | |
1683 | } | |
1684 | return false; | |
1685 | } | |
1686 | ||
1687 | static bool throtl_can_upgrade(struct throtl_data *td, | |
1688 | struct throtl_grp *this_tg) | |
1689 | { | |
1690 | struct cgroup_subsys_state *pos_css; | |
1691 | struct blkcg_gq *blkg; | |
1692 | ||
1693 | if (td->limit_index != LIMIT_LOW) | |
1694 | return false; | |
1695 | ||
297e3d85 | 1696 | if (time_before(jiffies, td->low_downgrade_time + td->throtl_slice)) |
3f0abd80 SL |
1697 | return false; |
1698 | ||
c79892c5 SL |
1699 | rcu_read_lock(); |
1700 | blkg_for_each_descendant_post(blkg, pos_css, td->queue->root_blkg) { | |
1701 | struct throtl_grp *tg = blkg_to_tg(blkg); | |
1702 | ||
1703 | if (tg == this_tg) | |
1704 | continue; | |
1705 | if (!list_empty(&tg_to_blkg(tg)->blkcg->css.children)) | |
1706 | continue; | |
1707 | if (!throtl_hierarchy_can_upgrade(tg)) { | |
1708 | rcu_read_unlock(); | |
1709 | return false; | |
1710 | } | |
1711 | } | |
1712 | rcu_read_unlock(); | |
1713 | return true; | |
1714 | } | |
1715 | ||
1716 | static void throtl_upgrade_state(struct throtl_data *td) | |
1717 | { | |
1718 | struct cgroup_subsys_state *pos_css; | |
1719 | struct blkcg_gq *blkg; | |
1720 | ||
1721 | td->limit_index = LIMIT_MAX; | |
3f0abd80 | 1722 | td->low_upgrade_time = jiffies; |
7394e31f | 1723 | td->scale = 0; |
c79892c5 SL |
1724 | rcu_read_lock(); |
1725 | blkg_for_each_descendant_post(blkg, pos_css, td->queue->root_blkg) { | |
1726 | struct throtl_grp *tg = blkg_to_tg(blkg); | |
1727 | struct throtl_service_queue *sq = &tg->service_queue; | |
1728 | ||
1729 | tg->disptime = jiffies - 1; | |
1730 | throtl_select_dispatch(sq); | |
1731 | throtl_schedule_next_dispatch(sq, false); | |
1732 | } | |
1733 | rcu_read_unlock(); | |
1734 | throtl_select_dispatch(&td->service_queue); | |
1735 | throtl_schedule_next_dispatch(&td->service_queue, false); | |
1736 | queue_work(kthrotld_workqueue, &td->dispatch_work); | |
1737 | } | |
1738 | ||
3f0abd80 SL |
1739 | static void throtl_downgrade_state(struct throtl_data *td, int new) |
1740 | { | |
7394e31f SL |
1741 | td->scale /= 2; |
1742 | ||
1743 | if (td->scale) { | |
1744 | td->low_upgrade_time = jiffies - td->scale * td->throtl_slice; | |
1745 | return; | |
1746 | } | |
1747 | ||
3f0abd80 SL |
1748 | td->limit_index = new; |
1749 | td->low_downgrade_time = jiffies; | |
1750 | } | |
1751 | ||
1752 | static bool throtl_tg_can_downgrade(struct throtl_grp *tg) | |
1753 | { | |
1754 | struct throtl_data *td = tg->td; | |
1755 | unsigned long now = jiffies; | |
1756 | ||
aec24246 SL |
1757 | if (time_after_eq(now, tg->last_dispatch_time[READ] + |
1758 | td->throtl_slice) && | |
1759 | time_after_eq(now, tg->last_dispatch_time[WRITE] + | |
1760 | td->throtl_slice)) | |
1761 | return false; | |
3f0abd80 SL |
1762 | /* |
1763 | * If cgroup is below low limit, consider downgrade and throttle other | |
1764 | * cgroups | |
1765 | */ | |
297e3d85 SL |
1766 | if (time_after_eq(now, td->low_upgrade_time + td->throtl_slice) && |
1767 | time_after_eq(now, tg_last_low_overflow_time(tg) + | |
1768 | td->throtl_slice)) | |
3f0abd80 SL |
1769 | return true; |
1770 | return false; | |
1771 | } | |
1772 | ||
1773 | static bool throtl_hierarchy_can_downgrade(struct throtl_grp *tg) | |
1774 | { | |
1775 | while (true) { | |
1776 | if (!throtl_tg_can_downgrade(tg)) | |
1777 | return false; | |
1778 | tg = sq_to_tg(tg->service_queue.parent_sq); | |
1779 | if (!tg || !tg_to_blkg(tg)->parent) | |
1780 | break; | |
1781 | } | |
1782 | return true; | |
1783 | } | |
1784 | ||
1785 | static void throtl_downgrade_check(struct throtl_grp *tg) | |
1786 | { | |
1787 | uint64_t bps; | |
1788 | unsigned int iops; | |
1789 | unsigned long elapsed_time; | |
1790 | unsigned long now = jiffies; | |
1791 | ||
1792 | if (tg->td->limit_index != LIMIT_MAX || | |
1793 | !tg->td->limit_valid[LIMIT_LOW]) | |
1794 | return; | |
1795 | if (!list_empty(&tg_to_blkg(tg)->blkcg->css.children)) | |
1796 | return; | |
297e3d85 | 1797 | if (time_after(tg->last_check_time + tg->td->throtl_slice, now)) |
3f0abd80 SL |
1798 | return; |
1799 | ||
1800 | elapsed_time = now - tg->last_check_time; | |
1801 | tg->last_check_time = now; | |
1802 | ||
297e3d85 SL |
1803 | if (time_before(now, tg_last_low_overflow_time(tg) + |
1804 | tg->td->throtl_slice)) | |
3f0abd80 SL |
1805 | return; |
1806 | ||
1807 | if (tg->bps[READ][LIMIT_LOW]) { | |
1808 | bps = tg->last_bytes_disp[READ] * HZ; | |
1809 | do_div(bps, elapsed_time); | |
1810 | if (bps >= tg->bps[READ][LIMIT_LOW]) | |
1811 | tg->last_low_overflow_time[READ] = now; | |
1812 | } | |
1813 | ||
1814 | if (tg->bps[WRITE][LIMIT_LOW]) { | |
1815 | bps = tg->last_bytes_disp[WRITE] * HZ; | |
1816 | do_div(bps, elapsed_time); | |
1817 | if (bps >= tg->bps[WRITE][LIMIT_LOW]) | |
1818 | tg->last_low_overflow_time[WRITE] = now; | |
1819 | } | |
1820 | ||
1821 | if (tg->iops[READ][LIMIT_LOW]) { | |
1822 | iops = tg->last_io_disp[READ] * HZ / elapsed_time; | |
1823 | if (iops >= tg->iops[READ][LIMIT_LOW]) | |
1824 | tg->last_low_overflow_time[READ] = now; | |
1825 | } | |
1826 | ||
1827 | if (tg->iops[WRITE][LIMIT_LOW]) { | |
1828 | iops = tg->last_io_disp[WRITE] * HZ / elapsed_time; | |
1829 | if (iops >= tg->iops[WRITE][LIMIT_LOW]) | |
1830 | tg->last_low_overflow_time[WRITE] = now; | |
1831 | } | |
1832 | ||
1833 | /* | |
1834 | * If cgroup is below low limit, consider downgrade and throttle other | |
1835 | * cgroups | |
1836 | */ | |
1837 | if (throtl_hierarchy_can_downgrade(tg)) | |
1838 | throtl_downgrade_state(tg->td, LIMIT_LOW); | |
1839 | ||
1840 | tg->last_bytes_disp[READ] = 0; | |
1841 | tg->last_bytes_disp[WRITE] = 0; | |
1842 | tg->last_io_disp[READ] = 0; | |
1843 | tg->last_io_disp[WRITE] = 0; | |
1844 | } | |
1845 | ||
ae118896 TH |
1846 | bool blk_throtl_bio(struct request_queue *q, struct blkcg_gq *blkg, |
1847 | struct bio *bio) | |
e43473b7 | 1848 | { |
c5cc2070 | 1849 | struct throtl_qnode *qn = NULL; |
ae118896 | 1850 | struct throtl_grp *tg = blkg_to_tg(blkg ?: q->root_blkg); |
73f0d49a | 1851 | struct throtl_service_queue *sq; |
0e9f4164 | 1852 | bool rw = bio_data_dir(bio); |
bc16a4f9 | 1853 | bool throttled = false; |
e43473b7 | 1854 | |
ae118896 TH |
1855 | WARN_ON_ONCE(!rcu_read_lock_held()); |
1856 | ||
2a0f61e6 | 1857 | /* see throtl_charge_bio() */ |
8d2bbd4c | 1858 | if (bio_flagged(bio, BIO_THROTTLED) || !tg->has_rules[rw]) |
bc16a4f9 | 1859 | goto out; |
e43473b7 VG |
1860 | |
1861 | spin_lock_irq(q->queue_lock); | |
c9589f03 TH |
1862 | |
1863 | if (unlikely(blk_queue_bypass(q))) | |
bc16a4f9 | 1864 | goto out_unlock; |
f469a7b4 | 1865 | |
73f0d49a TH |
1866 | sq = &tg->service_queue; |
1867 | ||
c79892c5 | 1868 | again: |
9e660acf | 1869 | while (true) { |
aec24246 | 1870 | tg->last_dispatch_time[rw] = jiffies; |
3f0abd80 SL |
1871 | if (tg->last_low_overflow_time[rw] == 0) |
1872 | tg->last_low_overflow_time[rw] = jiffies; | |
1873 | throtl_downgrade_check(tg); | |
9e660acf TH |
1874 | /* throtl is FIFO - if bios are already queued, should queue */ |
1875 | if (sq->nr_queued[rw]) | |
1876 | break; | |
de701c74 | 1877 | |
9e660acf | 1878 | /* if above limits, break to queue */ |
c79892c5 | 1879 | if (!tg_may_dispatch(tg, bio, NULL)) { |
3f0abd80 | 1880 | tg->last_low_overflow_time[rw] = jiffies; |
c79892c5 SL |
1881 | if (throtl_can_upgrade(tg->td, tg)) { |
1882 | throtl_upgrade_state(tg->td); | |
1883 | goto again; | |
1884 | } | |
9e660acf | 1885 | break; |
c79892c5 | 1886 | } |
9e660acf TH |
1887 | |
1888 | /* within limits, let's charge and dispatch directly */ | |
e43473b7 | 1889 | throtl_charge_bio(tg, bio); |
04521db0 VG |
1890 | |
1891 | /* | |
1892 | * We need to trim slice even when bios are not being queued | |
1893 | * otherwise it might happen that a bio is not queued for | |
1894 | * a long time and slice keeps on extending and trim is not | |
1895 | * called for a long time. Now if limits are reduced suddenly | |
1896 | * we take into account all the IO dispatched so far at new | |
1897 | * low rate and * newly queued IO gets a really long dispatch | |
1898 | * time. | |
1899 | * | |
1900 | * So keep on trimming slice even if bio is not queued. | |
1901 | */ | |
0f3457f6 | 1902 | throtl_trim_slice(tg, rw); |
9e660acf TH |
1903 | |
1904 | /* | |
1905 | * @bio passed through this layer without being throttled. | |
1906 | * Climb up the ladder. If we''re already at the top, it | |
1907 | * can be executed directly. | |
1908 | */ | |
c5cc2070 | 1909 | qn = &tg->qnode_on_parent[rw]; |
9e660acf TH |
1910 | sq = sq->parent_sq; |
1911 | tg = sq_to_tg(sq); | |
1912 | if (!tg) | |
1913 | goto out_unlock; | |
e43473b7 VG |
1914 | } |
1915 | ||
9e660acf | 1916 | /* out-of-limit, queue to @tg */ |
fda6f272 TH |
1917 | throtl_log(sq, "[%c] bio. bdisp=%llu sz=%u bps=%llu iodisp=%u iops=%u queued=%d/%d", |
1918 | rw == READ ? 'R' : 'W', | |
9f626e37 SL |
1919 | tg->bytes_disp[rw], bio->bi_iter.bi_size, |
1920 | tg_bps_limit(tg, rw), | |
1921 | tg->io_disp[rw], tg_iops_limit(tg, rw), | |
fda6f272 | 1922 | sq->nr_queued[READ], sq->nr_queued[WRITE]); |
e43473b7 | 1923 | |
3f0abd80 SL |
1924 | tg->last_low_overflow_time[rw] = jiffies; |
1925 | ||
671058fb | 1926 | bio_associate_current(bio); |
6bc9c2b4 | 1927 | tg->td->nr_queued[rw]++; |
c5cc2070 | 1928 | throtl_add_bio_tg(bio, qn, tg); |
bc16a4f9 | 1929 | throttled = true; |
e43473b7 | 1930 | |
7f52f98c TH |
1931 | /* |
1932 | * Update @tg's dispatch time and force schedule dispatch if @tg | |
1933 | * was empty before @bio. The forced scheduling isn't likely to | |
1934 | * cause undue delay as @bio is likely to be dispatched directly if | |
1935 | * its @tg's disptime is not in the future. | |
1936 | */ | |
0e9f4164 | 1937 | if (tg->flags & THROTL_TG_WAS_EMPTY) { |
77216b04 | 1938 | tg_update_disptime(tg); |
7f52f98c | 1939 | throtl_schedule_next_dispatch(tg->service_queue.parent_sq, true); |
e43473b7 VG |
1940 | } |
1941 | ||
bc16a4f9 | 1942 | out_unlock: |
e43473b7 | 1943 | spin_unlock_irq(q->queue_lock); |
bc16a4f9 | 1944 | out: |
2a0f61e6 TH |
1945 | /* |
1946 | * As multiple blk-throtls may stack in the same issue path, we | |
1947 | * don't want bios to leave with the flag set. Clear the flag if | |
1948 | * being issued. | |
1949 | */ | |
1950 | if (!throttled) | |
8d2bbd4c | 1951 | bio_clear_flag(bio, BIO_THROTTLED); |
bc16a4f9 | 1952 | return throttled; |
e43473b7 VG |
1953 | } |
1954 | ||
2a12f0dc TH |
1955 | /* |
1956 | * Dispatch all bios from all children tg's queued on @parent_sq. On | |
1957 | * return, @parent_sq is guaranteed to not have any active children tg's | |
1958 | * and all bios from previously active tg's are on @parent_sq->bio_lists[]. | |
1959 | */ | |
1960 | static void tg_drain_bios(struct throtl_service_queue *parent_sq) | |
1961 | { | |
1962 | struct throtl_grp *tg; | |
1963 | ||
1964 | while ((tg = throtl_rb_first(parent_sq))) { | |
1965 | struct throtl_service_queue *sq = &tg->service_queue; | |
1966 | struct bio *bio; | |
1967 | ||
1968 | throtl_dequeue_tg(tg); | |
1969 | ||
c5cc2070 | 1970 | while ((bio = throtl_peek_queued(&sq->queued[READ]))) |
2a12f0dc | 1971 | tg_dispatch_one_bio(tg, bio_data_dir(bio)); |
c5cc2070 | 1972 | while ((bio = throtl_peek_queued(&sq->queued[WRITE]))) |
2a12f0dc TH |
1973 | tg_dispatch_one_bio(tg, bio_data_dir(bio)); |
1974 | } | |
1975 | } | |
1976 | ||
c9a929dd TH |
1977 | /** |
1978 | * blk_throtl_drain - drain throttled bios | |
1979 | * @q: request_queue to drain throttled bios for | |
1980 | * | |
1981 | * Dispatch all currently throttled bios on @q through ->make_request_fn(). | |
1982 | */ | |
1983 | void blk_throtl_drain(struct request_queue *q) | |
1984 | __releases(q->queue_lock) __acquires(q->queue_lock) | |
1985 | { | |
1986 | struct throtl_data *td = q->td; | |
2a12f0dc | 1987 | struct blkcg_gq *blkg; |
492eb21b | 1988 | struct cgroup_subsys_state *pos_css; |
c9a929dd | 1989 | struct bio *bio; |
651930bc | 1990 | int rw; |
c9a929dd | 1991 | |
8bcb6c7d | 1992 | queue_lockdep_assert_held(q); |
2a12f0dc | 1993 | rcu_read_lock(); |
c9a929dd | 1994 | |
2a12f0dc TH |
1995 | /* |
1996 | * Drain each tg while doing post-order walk on the blkg tree, so | |
1997 | * that all bios are propagated to td->service_queue. It'd be | |
1998 | * better to walk service_queue tree directly but blkg walk is | |
1999 | * easier. | |
2000 | */ | |
492eb21b | 2001 | blkg_for_each_descendant_post(blkg, pos_css, td->queue->root_blkg) |
2a12f0dc | 2002 | tg_drain_bios(&blkg_to_tg(blkg)->service_queue); |
73f0d49a | 2003 | |
2a12f0dc TH |
2004 | /* finally, transfer bios from top-level tg's into the td */ |
2005 | tg_drain_bios(&td->service_queue); | |
2006 | ||
2007 | rcu_read_unlock(); | |
c9a929dd TH |
2008 | spin_unlock_irq(q->queue_lock); |
2009 | ||
2a12f0dc | 2010 | /* all bios now should be in td->service_queue, issue them */ |
651930bc | 2011 | for (rw = READ; rw <= WRITE; rw++) |
c5cc2070 TH |
2012 | while ((bio = throtl_pop_queued(&td->service_queue.queued[rw], |
2013 | NULL))) | |
651930bc | 2014 | generic_make_request(bio); |
c9a929dd TH |
2015 | |
2016 | spin_lock_irq(q->queue_lock); | |
2017 | } | |
2018 | ||
e43473b7 VG |
2019 | int blk_throtl_init(struct request_queue *q) |
2020 | { | |
2021 | struct throtl_data *td; | |
a2b1693b | 2022 | int ret; |
e43473b7 VG |
2023 | |
2024 | td = kzalloc_node(sizeof(*td), GFP_KERNEL, q->node); | |
2025 | if (!td) | |
2026 | return -ENOMEM; | |
2027 | ||
69df0ab0 | 2028 | INIT_WORK(&td->dispatch_work, blk_throtl_dispatch_work_fn); |
b2ce2643 | 2029 | throtl_service_queue_init(&td->service_queue); |
e43473b7 | 2030 | |
cd1604fa | 2031 | q->td = td; |
29b12589 | 2032 | td->queue = q; |
02977e4a | 2033 | |
9f626e37 | 2034 | td->limit_valid[LIMIT_MAX] = true; |
cd5ab1b0 | 2035 | td->limit_index = LIMIT_MAX; |
3f0abd80 SL |
2036 | td->low_upgrade_time = jiffies; |
2037 | td->low_downgrade_time = jiffies; | |
a2b1693b | 2038 | /* activate policy */ |
3c798398 | 2039 | ret = blkcg_activate_policy(q, &blkcg_policy_throtl); |
a2b1693b | 2040 | if (ret) |
f51b802c | 2041 | kfree(td); |
a2b1693b | 2042 | return ret; |
e43473b7 VG |
2043 | } |
2044 | ||
2045 | void blk_throtl_exit(struct request_queue *q) | |
2046 | { | |
c875f4d0 | 2047 | BUG_ON(!q->td); |
da527770 | 2048 | throtl_shutdown_wq(q); |
3c798398 | 2049 | blkcg_deactivate_policy(q, &blkcg_policy_throtl); |
c9a929dd | 2050 | kfree(q->td); |
e43473b7 VG |
2051 | } |
2052 | ||
d61fcfa4 SL |
2053 | void blk_throtl_register_queue(struct request_queue *q) |
2054 | { | |
2055 | struct throtl_data *td; | |
2056 | ||
2057 | td = q->td; | |
2058 | BUG_ON(!td); | |
2059 | ||
2060 | if (blk_queue_nonrot(q)) | |
2061 | td->throtl_slice = DFL_THROTL_SLICE_SSD; | |
2062 | else | |
2063 | td->throtl_slice = DFL_THROTL_SLICE_HD; | |
2064 | #ifndef CONFIG_BLK_DEV_THROTTLING_LOW | |
2065 | /* if no low limit, use previous default */ | |
2066 | td->throtl_slice = DFL_THROTL_SLICE_HD; | |
2067 | #endif | |
2068 | } | |
2069 | ||
297e3d85 SL |
2070 | #ifdef CONFIG_BLK_DEV_THROTTLING_LOW |
2071 | ssize_t blk_throtl_sample_time_show(struct request_queue *q, char *page) | |
2072 | { | |
2073 | if (!q->td) | |
2074 | return -EINVAL; | |
2075 | return sprintf(page, "%u\n", jiffies_to_msecs(q->td->throtl_slice)); | |
2076 | } | |
2077 | ||
2078 | ssize_t blk_throtl_sample_time_store(struct request_queue *q, | |
2079 | const char *page, size_t count) | |
2080 | { | |
2081 | unsigned long v; | |
2082 | unsigned long t; | |
2083 | ||
2084 | if (!q->td) | |
2085 | return -EINVAL; | |
2086 | if (kstrtoul(page, 10, &v)) | |
2087 | return -EINVAL; | |
2088 | t = msecs_to_jiffies(v); | |
2089 | if (t == 0 || t > MAX_THROTL_SLICE) | |
2090 | return -EINVAL; | |
2091 | q->td->throtl_slice = t; | |
2092 | return count; | |
2093 | } | |
2094 | #endif | |
2095 | ||
e43473b7 VG |
2096 | static int __init throtl_init(void) |
2097 | { | |
450adcbe VG |
2098 | kthrotld_workqueue = alloc_workqueue("kthrotld", WQ_MEM_RECLAIM, 0); |
2099 | if (!kthrotld_workqueue) | |
2100 | panic("Failed to create kthrotld\n"); | |
2101 | ||
3c798398 | 2102 | return blkcg_policy_register(&blkcg_policy_throtl); |
e43473b7 VG |
2103 | } |
2104 | ||
2105 | module_init(throtl_init); |