Commit | Line | Data |
---|---|---|
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 | ||
21 | /* Throttling is performed over 100ms slice and after that slice is renewed */ | |
22 | static unsigned long throtl_slice = HZ/10; /* 100 ms */ | |
23 | ||
3c798398 | 24 | static struct blkcg_policy blkcg_policy_throtl; |
0381411e | 25 | |
450adcbe VG |
26 | /* A workqueue to queue throttle related work */ |
27 | static struct workqueue_struct *kthrotld_workqueue; | |
450adcbe | 28 | |
c5cc2070 TH |
29 | /* |
30 | * To implement hierarchical throttling, throtl_grps form a tree and bios | |
31 | * are dispatched upwards level by level until they reach the top and get | |
32 | * issued. When dispatching bios from the children and local group at each | |
33 | * level, if the bios are dispatched into a single bio_list, there's a risk | |
34 | * of a local or child group which can queue many bios at once filling up | |
35 | * the list starving others. | |
36 | * | |
37 | * To avoid such starvation, dispatched bios are queued separately | |
38 | * according to where they came from. When they are again dispatched to | |
39 | * the parent, they're popped in round-robin order so that no single source | |
40 | * hogs the dispatch window. | |
41 | * | |
42 | * throtl_qnode is used to keep the queued bios separated by their sources. | |
43 | * Bios are queued to throtl_qnode which in turn is queued to | |
44 | * throtl_service_queue and then dispatched in round-robin order. | |
45 | * | |
46 | * It's also used to track the reference counts on blkg's. A qnode always | |
47 | * belongs to a throtl_grp and gets queued on itself or the parent, so | |
48 | * incrementing the reference of the associated throtl_grp when a qnode is | |
49 | * queued and decrementing when dequeued is enough to keep the whole blkg | |
50 | * tree pinned while bios are in flight. | |
51 | */ | |
52 | struct throtl_qnode { | |
53 | struct list_head node; /* service_queue->queued[] */ | |
54 | struct bio_list bios; /* queued bios */ | |
55 | struct throtl_grp *tg; /* tg this qnode belongs to */ | |
56 | }; | |
57 | ||
c9e0332e | 58 | struct throtl_service_queue { |
77216b04 TH |
59 | struct throtl_service_queue *parent_sq; /* the parent service_queue */ |
60 | ||
73f0d49a TH |
61 | /* |
62 | * Bios queued directly to this service_queue or dispatched from | |
63 | * children throtl_grp's. | |
64 | */ | |
c5cc2070 | 65 | struct list_head queued[2]; /* throtl_qnode [READ/WRITE] */ |
73f0d49a TH |
66 | unsigned int nr_queued[2]; /* number of queued bios */ |
67 | ||
68 | /* | |
69 | * RB tree of active children throtl_grp's, which are sorted by | |
70 | * their ->disptime. | |
71 | */ | |
c9e0332e TH |
72 | struct rb_root pending_tree; /* RB tree of active tgs */ |
73 | struct rb_node *first_pending; /* first node in the tree */ | |
74 | unsigned int nr_pending; /* # queued in the tree */ | |
75 | unsigned long first_pending_disptime; /* disptime of the first tg */ | |
69df0ab0 | 76 | struct timer_list pending_timer; /* fires on first_pending_disptime */ |
e43473b7 VG |
77 | }; |
78 | ||
5b2c16aa TH |
79 | enum tg_state_flags { |
80 | THROTL_TG_PENDING = 1 << 0, /* on parent's pending tree */ | |
0e9f4164 | 81 | THROTL_TG_WAS_EMPTY = 1 << 1, /* bio_lists[] became non-empty */ |
5b2c16aa TH |
82 | }; |
83 | ||
e43473b7 VG |
84 | #define rb_entry_tg(node) rb_entry((node), struct throtl_grp, rb_node) |
85 | ||
9f626e37 | 86 | enum { |
cd5ab1b0 | 87 | LIMIT_LOW, |
9f626e37 SL |
88 | LIMIT_MAX, |
89 | LIMIT_CNT, | |
90 | }; | |
91 | ||
e43473b7 | 92 | struct throtl_grp { |
f95a04af TH |
93 | /* must be the first member */ |
94 | struct blkg_policy_data pd; | |
95 | ||
c9e0332e | 96 | /* active throtl group service_queue member */ |
e43473b7 VG |
97 | struct rb_node rb_node; |
98 | ||
0f3457f6 TH |
99 | /* throtl_data this group belongs to */ |
100 | struct throtl_data *td; | |
101 | ||
49a2f1e3 TH |
102 | /* this group's service queue */ |
103 | struct throtl_service_queue service_queue; | |
104 | ||
c5cc2070 TH |
105 | /* |
106 | * qnode_on_self is used when bios are directly queued to this | |
107 | * throtl_grp so that local bios compete fairly with bios | |
108 | * dispatched from children. qnode_on_parent is used when bios are | |
109 | * dispatched from this throtl_grp into its parent and will compete | |
110 | * with the sibling qnode_on_parents and the parent's | |
111 | * qnode_on_self. | |
112 | */ | |
113 | struct throtl_qnode qnode_on_self[2]; | |
114 | struct throtl_qnode qnode_on_parent[2]; | |
115 | ||
e43473b7 VG |
116 | /* |
117 | * Dispatch time in jiffies. This is the estimated time when group | |
118 | * will unthrottle and is ready to dispatch more bio. It is used as | |
119 | * key to sort active groups in service tree. | |
120 | */ | |
121 | unsigned long disptime; | |
122 | ||
e43473b7 VG |
123 | unsigned int flags; |
124 | ||
693e751e TH |
125 | /* are there any throtl rules between this group and td? */ |
126 | bool has_rules[2]; | |
127 | ||
cd5ab1b0 | 128 | /* internally used bytes per second rate limits */ |
9f626e37 | 129 | uint64_t bps[2][LIMIT_CNT]; |
cd5ab1b0 SL |
130 | /* user configured bps limits */ |
131 | uint64_t bps_conf[2][LIMIT_CNT]; | |
e43473b7 | 132 | |
cd5ab1b0 | 133 | /* internally used IOPS limits */ |
9f626e37 | 134 | unsigned int iops[2][LIMIT_CNT]; |
cd5ab1b0 SL |
135 | /* user configured IOPS limits */ |
136 | unsigned int iops_conf[2][LIMIT_CNT]; | |
8e89d13f | 137 | |
e43473b7 VG |
138 | /* Number of bytes disptached in current slice */ |
139 | uint64_t bytes_disp[2]; | |
8e89d13f VG |
140 | /* Number of bio's dispatched in current slice */ |
141 | unsigned int io_disp[2]; | |
e43473b7 | 142 | |
3f0abd80 SL |
143 | unsigned long last_low_overflow_time[2]; |
144 | ||
145 | uint64_t last_bytes_disp[2]; | |
146 | unsigned int last_io_disp[2]; | |
147 | ||
148 | unsigned long last_check_time; | |
149 | ||
e43473b7 VG |
150 | /* When did we start a new slice */ |
151 | unsigned long slice_start[2]; | |
152 | unsigned long slice_end[2]; | |
153 | }; | |
154 | ||
155 | struct throtl_data | |
156 | { | |
e43473b7 | 157 | /* service tree for active throtl groups */ |
c9e0332e | 158 | struct throtl_service_queue service_queue; |
e43473b7 | 159 | |
e43473b7 VG |
160 | struct request_queue *queue; |
161 | ||
162 | /* Total Number of queued bios on READ and WRITE lists */ | |
163 | unsigned int nr_queued[2]; | |
164 | ||
e43473b7 | 165 | /* Work for dispatching throttled bios */ |
69df0ab0 | 166 | struct work_struct dispatch_work; |
9f626e37 SL |
167 | unsigned int limit_index; |
168 | bool limit_valid[LIMIT_CNT]; | |
3f0abd80 SL |
169 | |
170 | unsigned long low_upgrade_time; | |
171 | unsigned long low_downgrade_time; | |
e43473b7 VG |
172 | }; |
173 | ||
69df0ab0 TH |
174 | static void throtl_pending_timer_fn(unsigned long arg); |
175 | ||
f95a04af TH |
176 | static inline struct throtl_grp *pd_to_tg(struct blkg_policy_data *pd) |
177 | { | |
178 | return pd ? container_of(pd, struct throtl_grp, pd) : NULL; | |
179 | } | |
180 | ||
3c798398 | 181 | static inline struct throtl_grp *blkg_to_tg(struct blkcg_gq *blkg) |
0381411e | 182 | { |
f95a04af | 183 | return pd_to_tg(blkg_to_pd(blkg, &blkcg_policy_throtl)); |
0381411e TH |
184 | } |
185 | ||
3c798398 | 186 | static inline struct blkcg_gq *tg_to_blkg(struct throtl_grp *tg) |
0381411e | 187 | { |
f95a04af | 188 | return pd_to_blkg(&tg->pd); |
0381411e TH |
189 | } |
190 | ||
fda6f272 TH |
191 | /** |
192 | * sq_to_tg - return the throl_grp the specified service queue belongs to | |
193 | * @sq: the throtl_service_queue of interest | |
194 | * | |
195 | * Return the throtl_grp @sq belongs to. If @sq is the top-level one | |
196 | * embedded in throtl_data, %NULL is returned. | |
197 | */ | |
198 | static struct throtl_grp *sq_to_tg(struct throtl_service_queue *sq) | |
199 | { | |
200 | if (sq && sq->parent_sq) | |
201 | return container_of(sq, struct throtl_grp, service_queue); | |
202 | else | |
203 | return NULL; | |
204 | } | |
205 | ||
206 | /** | |
207 | * sq_to_td - return throtl_data the specified service queue belongs to | |
208 | * @sq: the throtl_service_queue of interest | |
209 | * | |
b43daedc | 210 | * A service_queue can be embedded in either a throtl_grp or throtl_data. |
fda6f272 TH |
211 | * Determine the associated throtl_data accordingly and return it. |
212 | */ | |
213 | static struct throtl_data *sq_to_td(struct throtl_service_queue *sq) | |
214 | { | |
215 | struct throtl_grp *tg = sq_to_tg(sq); | |
216 | ||
217 | if (tg) | |
218 | return tg->td; | |
219 | else | |
220 | return container_of(sq, struct throtl_data, service_queue); | |
221 | } | |
222 | ||
9f626e37 SL |
223 | static uint64_t tg_bps_limit(struct throtl_grp *tg, int rw) |
224 | { | |
b22c417c SL |
225 | struct blkcg_gq *blkg = tg_to_blkg(tg); |
226 | uint64_t ret; | |
227 | ||
228 | if (cgroup_subsys_on_dfl(io_cgrp_subsys) && !blkg->parent) | |
229 | return U64_MAX; | |
230 | ret = tg->bps[rw][tg->td->limit_index]; | |
231 | if (ret == 0 && tg->td->limit_index == LIMIT_LOW) | |
232 | return tg->bps[rw][LIMIT_MAX]; | |
233 | return ret; | |
9f626e37 SL |
234 | } |
235 | ||
236 | static unsigned int tg_iops_limit(struct throtl_grp *tg, int rw) | |
237 | { | |
b22c417c SL |
238 | struct blkcg_gq *blkg = tg_to_blkg(tg); |
239 | unsigned int ret; | |
240 | ||
241 | if (cgroup_subsys_on_dfl(io_cgrp_subsys) && !blkg->parent) | |
242 | return UINT_MAX; | |
243 | ret = tg->iops[rw][tg->td->limit_index]; | |
244 | if (ret == 0 && tg->td->limit_index == LIMIT_LOW) | |
245 | return tg->iops[rw][LIMIT_MAX]; | |
246 | return ret; | |
9f626e37 SL |
247 | } |
248 | ||
fda6f272 TH |
249 | /** |
250 | * throtl_log - log debug message via blktrace | |
251 | * @sq: the service_queue being reported | |
252 | * @fmt: printf format string | |
253 | * @args: printf args | |
254 | * | |
255 | * The messages are prefixed with "throtl BLKG_NAME" if @sq belongs to a | |
256 | * throtl_grp; otherwise, just "throtl". | |
fda6f272 TH |
257 | */ |
258 | #define throtl_log(sq, fmt, args...) do { \ | |
259 | struct throtl_grp *__tg = sq_to_tg((sq)); \ | |
260 | struct throtl_data *__td = sq_to_td((sq)); \ | |
261 | \ | |
262 | (void)__td; \ | |
59fa0224 SL |
263 | if (likely(!blk_trace_note_message_enabled(__td->queue))) \ |
264 | break; \ | |
fda6f272 TH |
265 | if ((__tg)) { \ |
266 | char __pbuf[128]; \ | |
54e7ed12 | 267 | \ |
fda6f272 TH |
268 | blkg_path(tg_to_blkg(__tg), __pbuf, sizeof(__pbuf)); \ |
269 | blk_add_trace_msg(__td->queue, "throtl %s " fmt, __pbuf, ##args); \ | |
270 | } else { \ | |
271 | blk_add_trace_msg(__td->queue, "throtl " fmt, ##args); \ | |
272 | } \ | |
54e7ed12 | 273 | } while (0) |
e43473b7 | 274 | |
c5cc2070 TH |
275 | static void throtl_qnode_init(struct throtl_qnode *qn, struct throtl_grp *tg) |
276 | { | |
277 | INIT_LIST_HEAD(&qn->node); | |
278 | bio_list_init(&qn->bios); | |
279 | qn->tg = tg; | |
280 | } | |
281 | ||
282 | /** | |
283 | * throtl_qnode_add_bio - add a bio to a throtl_qnode and activate it | |
284 | * @bio: bio being added | |
285 | * @qn: qnode to add bio to | |
286 | * @queued: the service_queue->queued[] list @qn belongs to | |
287 | * | |
288 | * Add @bio to @qn and put @qn on @queued if it's not already on. | |
289 | * @qn->tg's reference count is bumped when @qn is activated. See the | |
290 | * comment on top of throtl_qnode definition for details. | |
291 | */ | |
292 | static void throtl_qnode_add_bio(struct bio *bio, struct throtl_qnode *qn, | |
293 | struct list_head *queued) | |
294 | { | |
295 | bio_list_add(&qn->bios, bio); | |
296 | if (list_empty(&qn->node)) { | |
297 | list_add_tail(&qn->node, queued); | |
298 | blkg_get(tg_to_blkg(qn->tg)); | |
299 | } | |
300 | } | |
301 | ||
302 | /** | |
303 | * throtl_peek_queued - peek the first bio on a qnode list | |
304 | * @queued: the qnode list to peek | |
305 | */ | |
306 | static struct bio *throtl_peek_queued(struct list_head *queued) | |
307 | { | |
308 | struct throtl_qnode *qn = list_first_entry(queued, struct throtl_qnode, node); | |
309 | struct bio *bio; | |
310 | ||
311 | if (list_empty(queued)) | |
312 | return NULL; | |
313 | ||
314 | bio = bio_list_peek(&qn->bios); | |
315 | WARN_ON_ONCE(!bio); | |
316 | return bio; | |
317 | } | |
318 | ||
319 | /** | |
320 | * throtl_pop_queued - pop the first bio form a qnode list | |
321 | * @queued: the qnode list to pop a bio from | |
322 | * @tg_to_put: optional out argument for throtl_grp to put | |
323 | * | |
324 | * Pop the first bio from the qnode list @queued. After popping, the first | |
325 | * qnode is removed from @queued if empty or moved to the end of @queued so | |
326 | * that the popping order is round-robin. | |
327 | * | |
328 | * When the first qnode is removed, its associated throtl_grp should be put | |
329 | * too. If @tg_to_put is NULL, this function automatically puts it; | |
330 | * otherwise, *@tg_to_put is set to the throtl_grp to put and the caller is | |
331 | * responsible for putting it. | |
332 | */ | |
333 | static struct bio *throtl_pop_queued(struct list_head *queued, | |
334 | struct throtl_grp **tg_to_put) | |
335 | { | |
336 | struct throtl_qnode *qn = list_first_entry(queued, struct throtl_qnode, node); | |
337 | struct bio *bio; | |
338 | ||
339 | if (list_empty(queued)) | |
340 | return NULL; | |
341 | ||
342 | bio = bio_list_pop(&qn->bios); | |
343 | WARN_ON_ONCE(!bio); | |
344 | ||
345 | if (bio_list_empty(&qn->bios)) { | |
346 | list_del_init(&qn->node); | |
347 | if (tg_to_put) | |
348 | *tg_to_put = qn->tg; | |
349 | else | |
350 | blkg_put(tg_to_blkg(qn->tg)); | |
351 | } else { | |
352 | list_move_tail(&qn->node, queued); | |
353 | } | |
354 | ||
355 | return bio; | |
356 | } | |
357 | ||
49a2f1e3 | 358 | /* init a service_queue, assumes the caller zeroed it */ |
b2ce2643 | 359 | static void throtl_service_queue_init(struct throtl_service_queue *sq) |
49a2f1e3 | 360 | { |
c5cc2070 TH |
361 | INIT_LIST_HEAD(&sq->queued[0]); |
362 | INIT_LIST_HEAD(&sq->queued[1]); | |
49a2f1e3 | 363 | sq->pending_tree = RB_ROOT; |
69df0ab0 TH |
364 | setup_timer(&sq->pending_timer, throtl_pending_timer_fn, |
365 | (unsigned long)sq); | |
366 | } | |
367 | ||
001bea73 TH |
368 | static struct blkg_policy_data *throtl_pd_alloc(gfp_t gfp, int node) |
369 | { | |
4fb72036 | 370 | struct throtl_grp *tg; |
24bdb8ef | 371 | int rw; |
4fb72036 TH |
372 | |
373 | tg = kzalloc_node(sizeof(*tg), gfp, node); | |
374 | if (!tg) | |
77ea7338 | 375 | return NULL; |
4fb72036 | 376 | |
b2ce2643 TH |
377 | throtl_service_queue_init(&tg->service_queue); |
378 | ||
379 | for (rw = READ; rw <= WRITE; rw++) { | |
380 | throtl_qnode_init(&tg->qnode_on_self[rw], tg); | |
381 | throtl_qnode_init(&tg->qnode_on_parent[rw], tg); | |
382 | } | |
383 | ||
384 | RB_CLEAR_NODE(&tg->rb_node); | |
9f626e37 SL |
385 | tg->bps[READ][LIMIT_MAX] = U64_MAX; |
386 | tg->bps[WRITE][LIMIT_MAX] = U64_MAX; | |
387 | tg->iops[READ][LIMIT_MAX] = UINT_MAX; | |
388 | tg->iops[WRITE][LIMIT_MAX] = UINT_MAX; | |
cd5ab1b0 SL |
389 | tg->bps_conf[READ][LIMIT_MAX] = U64_MAX; |
390 | tg->bps_conf[WRITE][LIMIT_MAX] = U64_MAX; | |
391 | tg->iops_conf[READ][LIMIT_MAX] = UINT_MAX; | |
392 | tg->iops_conf[WRITE][LIMIT_MAX] = UINT_MAX; | |
393 | /* LIMIT_LOW will have default value 0 */ | |
b2ce2643 | 394 | |
4fb72036 | 395 | return &tg->pd; |
001bea73 TH |
396 | } |
397 | ||
a9520cd6 | 398 | static void throtl_pd_init(struct blkg_policy_data *pd) |
a29a171e | 399 | { |
a9520cd6 TH |
400 | struct throtl_grp *tg = pd_to_tg(pd); |
401 | struct blkcg_gq *blkg = tg_to_blkg(tg); | |
77216b04 | 402 | struct throtl_data *td = blkg->q->td; |
b2ce2643 | 403 | struct throtl_service_queue *sq = &tg->service_queue; |
cd1604fa | 404 | |
9138125b | 405 | /* |
aa6ec29b | 406 | * If on the default hierarchy, we switch to properly hierarchical |
9138125b TH |
407 | * behavior where limits on a given throtl_grp are applied to the |
408 | * whole subtree rather than just the group itself. e.g. If 16M | |
409 | * read_bps limit is set on the root group, the whole system can't | |
410 | * exceed 16M for the device. | |
411 | * | |
aa6ec29b | 412 | * If not on the default hierarchy, the broken flat hierarchy |
9138125b TH |
413 | * behavior is retained where all throtl_grps are treated as if |
414 | * they're all separate root groups right below throtl_data. | |
415 | * Limits of a group don't interact with limits of other groups | |
416 | * regardless of the position of the group in the hierarchy. | |
417 | */ | |
b2ce2643 | 418 | sq->parent_sq = &td->service_queue; |
9e10a130 | 419 | if (cgroup_subsys_on_dfl(io_cgrp_subsys) && blkg->parent) |
b2ce2643 | 420 | sq->parent_sq = &blkg_to_tg(blkg->parent)->service_queue; |
77216b04 | 421 | tg->td = td; |
8a3d2615 TH |
422 | } |
423 | ||
693e751e TH |
424 | /* |
425 | * Set has_rules[] if @tg or any of its parents have limits configured. | |
426 | * This doesn't require walking up to the top of the hierarchy as the | |
427 | * parent's has_rules[] is guaranteed to be correct. | |
428 | */ | |
429 | static void tg_update_has_rules(struct throtl_grp *tg) | |
430 | { | |
431 | struct throtl_grp *parent_tg = sq_to_tg(tg->service_queue.parent_sq); | |
9f626e37 | 432 | struct throtl_data *td = tg->td; |
693e751e TH |
433 | int rw; |
434 | ||
435 | for (rw = READ; rw <= WRITE; rw++) | |
436 | tg->has_rules[rw] = (parent_tg && parent_tg->has_rules[rw]) || | |
9f626e37 SL |
437 | (td->limit_valid[td->limit_index] && |
438 | (tg_bps_limit(tg, rw) != U64_MAX || | |
439 | tg_iops_limit(tg, rw) != UINT_MAX)); | |
693e751e TH |
440 | } |
441 | ||
a9520cd6 | 442 | static void throtl_pd_online(struct blkg_policy_data *pd) |
693e751e TH |
443 | { |
444 | /* | |
445 | * We don't want new groups to escape the limits of its ancestors. | |
446 | * Update has_rules[] after a new group is brought online. | |
447 | */ | |
a9520cd6 | 448 | tg_update_has_rules(pd_to_tg(pd)); |
693e751e TH |
449 | } |
450 | ||
cd5ab1b0 SL |
451 | static void blk_throtl_update_limit_valid(struct throtl_data *td) |
452 | { | |
453 | struct cgroup_subsys_state *pos_css; | |
454 | struct blkcg_gq *blkg; | |
455 | bool low_valid = false; | |
456 | ||
457 | rcu_read_lock(); | |
458 | blkg_for_each_descendant_post(blkg, pos_css, td->queue->root_blkg) { | |
459 | struct throtl_grp *tg = blkg_to_tg(blkg); | |
460 | ||
461 | if (tg->bps[READ][LIMIT_LOW] || tg->bps[WRITE][LIMIT_LOW] || | |
462 | tg->iops[READ][LIMIT_LOW] || tg->iops[WRITE][LIMIT_LOW]) | |
463 | low_valid = true; | |
464 | } | |
465 | rcu_read_unlock(); | |
466 | ||
467 | td->limit_valid[LIMIT_LOW] = low_valid; | |
468 | } | |
469 | ||
c79892c5 | 470 | static void throtl_upgrade_state(struct throtl_data *td); |
cd5ab1b0 SL |
471 | static void throtl_pd_offline(struct blkg_policy_data *pd) |
472 | { | |
473 | struct throtl_grp *tg = pd_to_tg(pd); | |
474 | ||
475 | tg->bps[READ][LIMIT_LOW] = 0; | |
476 | tg->bps[WRITE][LIMIT_LOW] = 0; | |
477 | tg->iops[READ][LIMIT_LOW] = 0; | |
478 | tg->iops[WRITE][LIMIT_LOW] = 0; | |
479 | ||
480 | blk_throtl_update_limit_valid(tg->td); | |
481 | ||
c79892c5 SL |
482 | if (!tg->td->limit_valid[tg->td->limit_index]) |
483 | throtl_upgrade_state(tg->td); | |
cd5ab1b0 SL |
484 | } |
485 | ||
001bea73 TH |
486 | static void throtl_pd_free(struct blkg_policy_data *pd) |
487 | { | |
4fb72036 TH |
488 | struct throtl_grp *tg = pd_to_tg(pd); |
489 | ||
b2ce2643 | 490 | del_timer_sync(&tg->service_queue.pending_timer); |
4fb72036 | 491 | kfree(tg); |
001bea73 TH |
492 | } |
493 | ||
0049af73 TH |
494 | static struct throtl_grp * |
495 | throtl_rb_first(struct throtl_service_queue *parent_sq) | |
e43473b7 VG |
496 | { |
497 | /* Service tree is empty */ | |
0049af73 | 498 | if (!parent_sq->nr_pending) |
e43473b7 VG |
499 | return NULL; |
500 | ||
0049af73 TH |
501 | if (!parent_sq->first_pending) |
502 | parent_sq->first_pending = rb_first(&parent_sq->pending_tree); | |
e43473b7 | 503 | |
0049af73 TH |
504 | if (parent_sq->first_pending) |
505 | return rb_entry_tg(parent_sq->first_pending); | |
e43473b7 VG |
506 | |
507 | return NULL; | |
508 | } | |
509 | ||
510 | static void rb_erase_init(struct rb_node *n, struct rb_root *root) | |
511 | { | |
512 | rb_erase(n, root); | |
513 | RB_CLEAR_NODE(n); | |
514 | } | |
515 | ||
0049af73 TH |
516 | static void throtl_rb_erase(struct rb_node *n, |
517 | struct throtl_service_queue *parent_sq) | |
e43473b7 | 518 | { |
0049af73 TH |
519 | if (parent_sq->first_pending == n) |
520 | parent_sq->first_pending = NULL; | |
521 | rb_erase_init(n, &parent_sq->pending_tree); | |
522 | --parent_sq->nr_pending; | |
e43473b7 VG |
523 | } |
524 | ||
0049af73 | 525 | static void update_min_dispatch_time(struct throtl_service_queue *parent_sq) |
e43473b7 VG |
526 | { |
527 | struct throtl_grp *tg; | |
528 | ||
0049af73 | 529 | tg = throtl_rb_first(parent_sq); |
e43473b7 VG |
530 | if (!tg) |
531 | return; | |
532 | ||
0049af73 | 533 | parent_sq->first_pending_disptime = tg->disptime; |
e43473b7 VG |
534 | } |
535 | ||
77216b04 | 536 | static void tg_service_queue_add(struct throtl_grp *tg) |
e43473b7 | 537 | { |
77216b04 | 538 | struct throtl_service_queue *parent_sq = tg->service_queue.parent_sq; |
0049af73 | 539 | struct rb_node **node = &parent_sq->pending_tree.rb_node; |
e43473b7 VG |
540 | struct rb_node *parent = NULL; |
541 | struct throtl_grp *__tg; | |
542 | unsigned long key = tg->disptime; | |
543 | int left = 1; | |
544 | ||
545 | while (*node != NULL) { | |
546 | parent = *node; | |
547 | __tg = rb_entry_tg(parent); | |
548 | ||
549 | if (time_before(key, __tg->disptime)) | |
550 | node = &parent->rb_left; | |
551 | else { | |
552 | node = &parent->rb_right; | |
553 | left = 0; | |
554 | } | |
555 | } | |
556 | ||
557 | if (left) | |
0049af73 | 558 | parent_sq->first_pending = &tg->rb_node; |
e43473b7 VG |
559 | |
560 | rb_link_node(&tg->rb_node, parent, node); | |
0049af73 | 561 | rb_insert_color(&tg->rb_node, &parent_sq->pending_tree); |
e43473b7 VG |
562 | } |
563 | ||
77216b04 | 564 | static void __throtl_enqueue_tg(struct throtl_grp *tg) |
e43473b7 | 565 | { |
77216b04 | 566 | tg_service_queue_add(tg); |
5b2c16aa | 567 | tg->flags |= THROTL_TG_PENDING; |
77216b04 | 568 | tg->service_queue.parent_sq->nr_pending++; |
e43473b7 VG |
569 | } |
570 | ||
77216b04 | 571 | static void throtl_enqueue_tg(struct throtl_grp *tg) |
e43473b7 | 572 | { |
5b2c16aa | 573 | if (!(tg->flags & THROTL_TG_PENDING)) |
77216b04 | 574 | __throtl_enqueue_tg(tg); |
e43473b7 VG |
575 | } |
576 | ||
77216b04 | 577 | static void __throtl_dequeue_tg(struct throtl_grp *tg) |
e43473b7 | 578 | { |
77216b04 | 579 | throtl_rb_erase(&tg->rb_node, tg->service_queue.parent_sq); |
5b2c16aa | 580 | tg->flags &= ~THROTL_TG_PENDING; |
e43473b7 VG |
581 | } |
582 | ||
77216b04 | 583 | static void throtl_dequeue_tg(struct throtl_grp *tg) |
e43473b7 | 584 | { |
5b2c16aa | 585 | if (tg->flags & THROTL_TG_PENDING) |
77216b04 | 586 | __throtl_dequeue_tg(tg); |
e43473b7 VG |
587 | } |
588 | ||
a9131a27 | 589 | /* Call with queue lock held */ |
69df0ab0 TH |
590 | static void throtl_schedule_pending_timer(struct throtl_service_queue *sq, |
591 | unsigned long expires) | |
a9131a27 | 592 | { |
06cceedc SL |
593 | unsigned long max_expire = jiffies + 8 * throtl_slice; |
594 | ||
595 | /* | |
596 | * Since we are adjusting the throttle limit dynamically, the sleep | |
597 | * time calculated according to previous limit might be invalid. It's | |
598 | * possible the cgroup sleep time is very long and no other cgroups | |
599 | * have IO running so notify the limit changes. Make sure the cgroup | |
600 | * doesn't sleep too long to avoid the missed notification. | |
601 | */ | |
602 | if (time_after(expires, max_expire)) | |
603 | expires = max_expire; | |
69df0ab0 TH |
604 | mod_timer(&sq->pending_timer, expires); |
605 | throtl_log(sq, "schedule timer. delay=%lu jiffies=%lu", | |
606 | expires - jiffies, jiffies); | |
a9131a27 TH |
607 | } |
608 | ||
7f52f98c TH |
609 | /** |
610 | * throtl_schedule_next_dispatch - schedule the next dispatch cycle | |
611 | * @sq: the service_queue to schedule dispatch for | |
612 | * @force: force scheduling | |
613 | * | |
614 | * Arm @sq->pending_timer so that the next dispatch cycle starts on the | |
615 | * dispatch time of the first pending child. Returns %true if either timer | |
616 | * is armed or there's no pending child left. %false if the current | |
617 | * dispatch window is still open and the caller should continue | |
618 | * dispatching. | |
619 | * | |
620 | * If @force is %true, the dispatch timer is always scheduled and this | |
621 | * function is guaranteed to return %true. This is to be used when the | |
622 | * caller can't dispatch itself and needs to invoke pending_timer | |
623 | * unconditionally. Note that forced scheduling is likely to induce short | |
624 | * delay before dispatch starts even if @sq->first_pending_disptime is not | |
625 | * in the future and thus shouldn't be used in hot paths. | |
626 | */ | |
627 | static bool throtl_schedule_next_dispatch(struct throtl_service_queue *sq, | |
628 | bool force) | |
e43473b7 | 629 | { |
6a525600 | 630 | /* any pending children left? */ |
c9e0332e | 631 | if (!sq->nr_pending) |
7f52f98c | 632 | return true; |
e43473b7 | 633 | |
c9e0332e | 634 | update_min_dispatch_time(sq); |
e43473b7 | 635 | |
69df0ab0 | 636 | /* is the next dispatch time in the future? */ |
7f52f98c | 637 | if (force || time_after(sq->first_pending_disptime, jiffies)) { |
69df0ab0 | 638 | throtl_schedule_pending_timer(sq, sq->first_pending_disptime); |
7f52f98c | 639 | return true; |
69df0ab0 TH |
640 | } |
641 | ||
7f52f98c TH |
642 | /* tell the caller to continue dispatching */ |
643 | return false; | |
e43473b7 VG |
644 | } |
645 | ||
32ee5bc4 VG |
646 | static inline void throtl_start_new_slice_with_credit(struct throtl_grp *tg, |
647 | bool rw, unsigned long start) | |
648 | { | |
649 | tg->bytes_disp[rw] = 0; | |
650 | tg->io_disp[rw] = 0; | |
651 | ||
652 | /* | |
653 | * Previous slice has expired. We must have trimmed it after last | |
654 | * bio dispatch. That means since start of last slice, we never used | |
655 | * that bandwidth. Do try to make use of that bandwidth while giving | |
656 | * credit. | |
657 | */ | |
658 | if (time_after_eq(start, tg->slice_start[rw])) | |
659 | tg->slice_start[rw] = start; | |
660 | ||
661 | tg->slice_end[rw] = jiffies + throtl_slice; | |
662 | throtl_log(&tg->service_queue, | |
663 | "[%c] new slice with credit start=%lu end=%lu jiffies=%lu", | |
664 | rw == READ ? 'R' : 'W', tg->slice_start[rw], | |
665 | tg->slice_end[rw], jiffies); | |
666 | } | |
667 | ||
0f3457f6 | 668 | static inline void throtl_start_new_slice(struct throtl_grp *tg, bool rw) |
e43473b7 VG |
669 | { |
670 | tg->bytes_disp[rw] = 0; | |
8e89d13f | 671 | tg->io_disp[rw] = 0; |
e43473b7 VG |
672 | tg->slice_start[rw] = jiffies; |
673 | tg->slice_end[rw] = jiffies + throtl_slice; | |
fda6f272 TH |
674 | throtl_log(&tg->service_queue, |
675 | "[%c] new slice start=%lu end=%lu jiffies=%lu", | |
676 | rw == READ ? 'R' : 'W', tg->slice_start[rw], | |
677 | tg->slice_end[rw], jiffies); | |
e43473b7 VG |
678 | } |
679 | ||
0f3457f6 TH |
680 | static inline void throtl_set_slice_end(struct throtl_grp *tg, bool rw, |
681 | unsigned long jiffy_end) | |
d1ae8ffd VG |
682 | { |
683 | tg->slice_end[rw] = roundup(jiffy_end, throtl_slice); | |
684 | } | |
685 | ||
0f3457f6 TH |
686 | static inline void throtl_extend_slice(struct throtl_grp *tg, bool rw, |
687 | unsigned long jiffy_end) | |
e43473b7 VG |
688 | { |
689 | tg->slice_end[rw] = roundup(jiffy_end, throtl_slice); | |
fda6f272 TH |
690 | throtl_log(&tg->service_queue, |
691 | "[%c] extend slice start=%lu end=%lu jiffies=%lu", | |
692 | rw == READ ? 'R' : 'W', tg->slice_start[rw], | |
693 | tg->slice_end[rw], jiffies); | |
e43473b7 VG |
694 | } |
695 | ||
696 | /* Determine if previously allocated or extended slice is complete or not */ | |
0f3457f6 | 697 | static bool throtl_slice_used(struct throtl_grp *tg, bool rw) |
e43473b7 VG |
698 | { |
699 | if (time_in_range(jiffies, tg->slice_start[rw], tg->slice_end[rw])) | |
5cf8c227 | 700 | return false; |
e43473b7 VG |
701 | |
702 | return 1; | |
703 | } | |
704 | ||
705 | /* Trim the used slices and adjust slice start accordingly */ | |
0f3457f6 | 706 | static inline void throtl_trim_slice(struct throtl_grp *tg, bool rw) |
e43473b7 | 707 | { |
3aad5d3e VG |
708 | unsigned long nr_slices, time_elapsed, io_trim; |
709 | u64 bytes_trim, tmp; | |
e43473b7 VG |
710 | |
711 | BUG_ON(time_before(tg->slice_end[rw], tg->slice_start[rw])); | |
712 | ||
713 | /* | |
714 | * If bps are unlimited (-1), then time slice don't get | |
715 | * renewed. Don't try to trim the slice if slice is used. A new | |
716 | * slice will start when appropriate. | |
717 | */ | |
0f3457f6 | 718 | if (throtl_slice_used(tg, rw)) |
e43473b7 VG |
719 | return; |
720 | ||
d1ae8ffd VG |
721 | /* |
722 | * A bio has been dispatched. Also adjust slice_end. It might happen | |
723 | * that initially cgroup limit was very low resulting in high | |
724 | * slice_end, but later limit was bumped up and bio was dispached | |
725 | * sooner, then we need to reduce slice_end. A high bogus slice_end | |
726 | * is bad because it does not allow new slice to start. | |
727 | */ | |
728 | ||
0f3457f6 | 729 | throtl_set_slice_end(tg, rw, jiffies + throtl_slice); |
d1ae8ffd | 730 | |
e43473b7 VG |
731 | time_elapsed = jiffies - tg->slice_start[rw]; |
732 | ||
733 | nr_slices = time_elapsed / throtl_slice; | |
734 | ||
735 | if (!nr_slices) | |
736 | return; | |
9f626e37 | 737 | tmp = tg_bps_limit(tg, rw) * throtl_slice * nr_slices; |
3aad5d3e VG |
738 | do_div(tmp, HZ); |
739 | bytes_trim = tmp; | |
e43473b7 | 740 | |
9f626e37 | 741 | io_trim = (tg_iops_limit(tg, rw) * throtl_slice * nr_slices) / HZ; |
e43473b7 | 742 | |
8e89d13f | 743 | if (!bytes_trim && !io_trim) |
e43473b7 VG |
744 | return; |
745 | ||
746 | if (tg->bytes_disp[rw] >= bytes_trim) | |
747 | tg->bytes_disp[rw] -= bytes_trim; | |
748 | else | |
749 | tg->bytes_disp[rw] = 0; | |
750 | ||
8e89d13f VG |
751 | if (tg->io_disp[rw] >= io_trim) |
752 | tg->io_disp[rw] -= io_trim; | |
753 | else | |
754 | tg->io_disp[rw] = 0; | |
755 | ||
e43473b7 VG |
756 | tg->slice_start[rw] += nr_slices * throtl_slice; |
757 | ||
fda6f272 TH |
758 | throtl_log(&tg->service_queue, |
759 | "[%c] trim slice nr=%lu bytes=%llu io=%lu start=%lu end=%lu jiffies=%lu", | |
760 | rw == READ ? 'R' : 'W', nr_slices, bytes_trim, io_trim, | |
761 | tg->slice_start[rw], tg->slice_end[rw], jiffies); | |
e43473b7 VG |
762 | } |
763 | ||
0f3457f6 TH |
764 | static bool tg_with_in_iops_limit(struct throtl_grp *tg, struct bio *bio, |
765 | unsigned long *wait) | |
e43473b7 VG |
766 | { |
767 | bool rw = bio_data_dir(bio); | |
8e89d13f | 768 | unsigned int io_allowed; |
e43473b7 | 769 | unsigned long jiffy_elapsed, jiffy_wait, jiffy_elapsed_rnd; |
c49c06e4 | 770 | u64 tmp; |
e43473b7 | 771 | |
8e89d13f | 772 | jiffy_elapsed = jiffy_elapsed_rnd = jiffies - tg->slice_start[rw]; |
e43473b7 | 773 | |
8e89d13f VG |
774 | /* Slice has just started. Consider one slice interval */ |
775 | if (!jiffy_elapsed) | |
776 | jiffy_elapsed_rnd = throtl_slice; | |
777 | ||
778 | jiffy_elapsed_rnd = roundup(jiffy_elapsed_rnd, throtl_slice); | |
779 | ||
c49c06e4 VG |
780 | /* |
781 | * jiffy_elapsed_rnd should not be a big value as minimum iops can be | |
782 | * 1 then at max jiffy elapsed should be equivalent of 1 second as we | |
783 | * will allow dispatch after 1 second and after that slice should | |
784 | * have been trimmed. | |
785 | */ | |
786 | ||
9f626e37 | 787 | tmp = (u64)tg_iops_limit(tg, rw) * jiffy_elapsed_rnd; |
c49c06e4 VG |
788 | do_div(tmp, HZ); |
789 | ||
790 | if (tmp > UINT_MAX) | |
791 | io_allowed = UINT_MAX; | |
792 | else | |
793 | io_allowed = tmp; | |
8e89d13f VG |
794 | |
795 | if (tg->io_disp[rw] + 1 <= io_allowed) { | |
e43473b7 VG |
796 | if (wait) |
797 | *wait = 0; | |
5cf8c227 | 798 | return true; |
e43473b7 VG |
799 | } |
800 | ||
8e89d13f | 801 | /* Calc approx time to dispatch */ |
9f626e37 | 802 | jiffy_wait = ((tg->io_disp[rw] + 1) * HZ) / tg_iops_limit(tg, rw) + 1; |
8e89d13f VG |
803 | |
804 | if (jiffy_wait > jiffy_elapsed) | |
805 | jiffy_wait = jiffy_wait - jiffy_elapsed; | |
806 | else | |
807 | jiffy_wait = 1; | |
808 | ||
809 | if (wait) | |
810 | *wait = jiffy_wait; | |
811 | return 0; | |
812 | } | |
813 | ||
0f3457f6 TH |
814 | static bool tg_with_in_bps_limit(struct throtl_grp *tg, struct bio *bio, |
815 | unsigned long *wait) | |
8e89d13f VG |
816 | { |
817 | bool rw = bio_data_dir(bio); | |
3aad5d3e | 818 | u64 bytes_allowed, extra_bytes, tmp; |
8e89d13f | 819 | unsigned long jiffy_elapsed, jiffy_wait, jiffy_elapsed_rnd; |
e43473b7 VG |
820 | |
821 | jiffy_elapsed = jiffy_elapsed_rnd = jiffies - tg->slice_start[rw]; | |
822 | ||
823 | /* Slice has just started. Consider one slice interval */ | |
824 | if (!jiffy_elapsed) | |
825 | jiffy_elapsed_rnd = throtl_slice; | |
826 | ||
827 | jiffy_elapsed_rnd = roundup(jiffy_elapsed_rnd, throtl_slice); | |
828 | ||
9f626e37 | 829 | tmp = tg_bps_limit(tg, rw) * jiffy_elapsed_rnd; |
5e901a2b | 830 | do_div(tmp, HZ); |
3aad5d3e | 831 | bytes_allowed = tmp; |
e43473b7 | 832 | |
4f024f37 | 833 | if (tg->bytes_disp[rw] + bio->bi_iter.bi_size <= bytes_allowed) { |
e43473b7 VG |
834 | if (wait) |
835 | *wait = 0; | |
5cf8c227 | 836 | return true; |
e43473b7 VG |
837 | } |
838 | ||
839 | /* Calc approx time to dispatch */ | |
4f024f37 | 840 | extra_bytes = tg->bytes_disp[rw] + bio->bi_iter.bi_size - bytes_allowed; |
9f626e37 | 841 | jiffy_wait = div64_u64(extra_bytes * HZ, tg_bps_limit(tg, rw)); |
e43473b7 VG |
842 | |
843 | if (!jiffy_wait) | |
844 | jiffy_wait = 1; | |
845 | ||
846 | /* | |
847 | * This wait time is without taking into consideration the rounding | |
848 | * up we did. Add that time also. | |
849 | */ | |
850 | jiffy_wait = jiffy_wait + (jiffy_elapsed_rnd - jiffy_elapsed); | |
e43473b7 VG |
851 | if (wait) |
852 | *wait = jiffy_wait; | |
8e89d13f VG |
853 | return 0; |
854 | } | |
855 | ||
856 | /* | |
857 | * Returns whether one can dispatch a bio or not. Also returns approx number | |
858 | * of jiffies to wait before this bio is with-in IO rate and can be dispatched | |
859 | */ | |
0f3457f6 TH |
860 | static bool tg_may_dispatch(struct throtl_grp *tg, struct bio *bio, |
861 | unsigned long *wait) | |
8e89d13f VG |
862 | { |
863 | bool rw = bio_data_dir(bio); | |
864 | unsigned long bps_wait = 0, iops_wait = 0, max_wait = 0; | |
865 | ||
866 | /* | |
867 | * Currently whole state machine of group depends on first bio | |
868 | * queued in the group bio list. So one should not be calling | |
869 | * this function with a different bio if there are other bios | |
870 | * queued. | |
871 | */ | |
73f0d49a | 872 | BUG_ON(tg->service_queue.nr_queued[rw] && |
c5cc2070 | 873 | bio != throtl_peek_queued(&tg->service_queue.queued[rw])); |
e43473b7 | 874 | |
8e89d13f | 875 | /* If tg->bps = -1, then BW is unlimited */ |
9f626e37 SL |
876 | if (tg_bps_limit(tg, rw) == U64_MAX && |
877 | tg_iops_limit(tg, rw) == UINT_MAX) { | |
8e89d13f VG |
878 | if (wait) |
879 | *wait = 0; | |
5cf8c227 | 880 | return true; |
8e89d13f VG |
881 | } |
882 | ||
883 | /* | |
884 | * If previous slice expired, start a new one otherwise renew/extend | |
885 | * existing slice to make sure it is at least throtl_slice interval | |
164c80ed VG |
886 | * long since now. New slice is started only for empty throttle group. |
887 | * If there is queued bio, that means there should be an active | |
888 | * slice and it should be extended instead. | |
8e89d13f | 889 | */ |
164c80ed | 890 | if (throtl_slice_used(tg, rw) && !(tg->service_queue.nr_queued[rw])) |
0f3457f6 | 891 | throtl_start_new_slice(tg, rw); |
8e89d13f VG |
892 | else { |
893 | if (time_before(tg->slice_end[rw], jiffies + throtl_slice)) | |
0f3457f6 | 894 | throtl_extend_slice(tg, rw, jiffies + throtl_slice); |
8e89d13f VG |
895 | } |
896 | ||
0f3457f6 TH |
897 | if (tg_with_in_bps_limit(tg, bio, &bps_wait) && |
898 | tg_with_in_iops_limit(tg, bio, &iops_wait)) { | |
8e89d13f VG |
899 | if (wait) |
900 | *wait = 0; | |
901 | return 1; | |
902 | } | |
903 | ||
904 | max_wait = max(bps_wait, iops_wait); | |
905 | ||
906 | if (wait) | |
907 | *wait = max_wait; | |
908 | ||
909 | if (time_before(tg->slice_end[rw], jiffies + max_wait)) | |
0f3457f6 | 910 | throtl_extend_slice(tg, rw, jiffies + max_wait); |
e43473b7 VG |
911 | |
912 | return 0; | |
913 | } | |
914 | ||
915 | static void throtl_charge_bio(struct throtl_grp *tg, struct bio *bio) | |
916 | { | |
917 | bool rw = bio_data_dir(bio); | |
e43473b7 VG |
918 | |
919 | /* Charge the bio to the group */ | |
4f024f37 | 920 | tg->bytes_disp[rw] += bio->bi_iter.bi_size; |
8e89d13f | 921 | tg->io_disp[rw]++; |
3f0abd80 SL |
922 | tg->last_bytes_disp[rw] += bio->bi_iter.bi_size; |
923 | tg->last_io_disp[rw]++; | |
e43473b7 | 924 | |
2a0f61e6 | 925 | /* |
8d2bbd4c | 926 | * BIO_THROTTLED is used to prevent the same bio to be throttled |
2a0f61e6 TH |
927 | * more than once as a throttled bio will go through blk-throtl the |
928 | * second time when it eventually gets issued. Set it when a bio | |
929 | * is being charged to a tg. | |
2a0f61e6 | 930 | */ |
8d2bbd4c CH |
931 | if (!bio_flagged(bio, BIO_THROTTLED)) |
932 | bio_set_flag(bio, BIO_THROTTLED); | |
e43473b7 VG |
933 | } |
934 | ||
c5cc2070 TH |
935 | /** |
936 | * throtl_add_bio_tg - add a bio to the specified throtl_grp | |
937 | * @bio: bio to add | |
938 | * @qn: qnode to use | |
939 | * @tg: the target throtl_grp | |
940 | * | |
941 | * Add @bio to @tg's service_queue using @qn. If @qn is not specified, | |
942 | * tg->qnode_on_self[] is used. | |
943 | */ | |
944 | static void throtl_add_bio_tg(struct bio *bio, struct throtl_qnode *qn, | |
945 | struct throtl_grp *tg) | |
e43473b7 | 946 | { |
73f0d49a | 947 | struct throtl_service_queue *sq = &tg->service_queue; |
e43473b7 VG |
948 | bool rw = bio_data_dir(bio); |
949 | ||
c5cc2070 TH |
950 | if (!qn) |
951 | qn = &tg->qnode_on_self[rw]; | |
952 | ||
0e9f4164 TH |
953 | /* |
954 | * If @tg doesn't currently have any bios queued in the same | |
955 | * direction, queueing @bio can change when @tg should be | |
956 | * dispatched. Mark that @tg was empty. This is automatically | |
957 | * cleaered on the next tg_update_disptime(). | |
958 | */ | |
959 | if (!sq->nr_queued[rw]) | |
960 | tg->flags |= THROTL_TG_WAS_EMPTY; | |
961 | ||
c5cc2070 TH |
962 | throtl_qnode_add_bio(bio, qn, &sq->queued[rw]); |
963 | ||
73f0d49a | 964 | sq->nr_queued[rw]++; |
77216b04 | 965 | throtl_enqueue_tg(tg); |
e43473b7 VG |
966 | } |
967 | ||
77216b04 | 968 | static void tg_update_disptime(struct throtl_grp *tg) |
e43473b7 | 969 | { |
73f0d49a | 970 | struct throtl_service_queue *sq = &tg->service_queue; |
e43473b7 VG |
971 | unsigned long read_wait = -1, write_wait = -1, min_wait = -1, disptime; |
972 | struct bio *bio; | |
973 | ||
d609af3a ME |
974 | bio = throtl_peek_queued(&sq->queued[READ]); |
975 | if (bio) | |
0f3457f6 | 976 | tg_may_dispatch(tg, bio, &read_wait); |
e43473b7 | 977 | |
d609af3a ME |
978 | bio = throtl_peek_queued(&sq->queued[WRITE]); |
979 | if (bio) | |
0f3457f6 | 980 | tg_may_dispatch(tg, bio, &write_wait); |
e43473b7 VG |
981 | |
982 | min_wait = min(read_wait, write_wait); | |
983 | disptime = jiffies + min_wait; | |
984 | ||
e43473b7 | 985 | /* Update dispatch time */ |
77216b04 | 986 | throtl_dequeue_tg(tg); |
e43473b7 | 987 | tg->disptime = disptime; |
77216b04 | 988 | throtl_enqueue_tg(tg); |
0e9f4164 TH |
989 | |
990 | /* see throtl_add_bio_tg() */ | |
991 | tg->flags &= ~THROTL_TG_WAS_EMPTY; | |
e43473b7 VG |
992 | } |
993 | ||
32ee5bc4 VG |
994 | static void start_parent_slice_with_credit(struct throtl_grp *child_tg, |
995 | struct throtl_grp *parent_tg, bool rw) | |
996 | { | |
997 | if (throtl_slice_used(parent_tg, rw)) { | |
998 | throtl_start_new_slice_with_credit(parent_tg, rw, | |
999 | child_tg->slice_start[rw]); | |
1000 | } | |
1001 | ||
1002 | } | |
1003 | ||
77216b04 | 1004 | static void tg_dispatch_one_bio(struct throtl_grp *tg, bool rw) |
e43473b7 | 1005 | { |
73f0d49a | 1006 | struct throtl_service_queue *sq = &tg->service_queue; |
6bc9c2b4 TH |
1007 | struct throtl_service_queue *parent_sq = sq->parent_sq; |
1008 | struct throtl_grp *parent_tg = sq_to_tg(parent_sq); | |
c5cc2070 | 1009 | struct throtl_grp *tg_to_put = NULL; |
e43473b7 VG |
1010 | struct bio *bio; |
1011 | ||
c5cc2070 TH |
1012 | /* |
1013 | * @bio is being transferred from @tg to @parent_sq. Popping a bio | |
1014 | * from @tg may put its reference and @parent_sq might end up | |
1015 | * getting released prematurely. Remember the tg to put and put it | |
1016 | * after @bio is transferred to @parent_sq. | |
1017 | */ | |
1018 | bio = throtl_pop_queued(&sq->queued[rw], &tg_to_put); | |
73f0d49a | 1019 | sq->nr_queued[rw]--; |
e43473b7 VG |
1020 | |
1021 | throtl_charge_bio(tg, bio); | |
6bc9c2b4 TH |
1022 | |
1023 | /* | |
1024 | * If our parent is another tg, we just need to transfer @bio to | |
1025 | * the parent using throtl_add_bio_tg(). If our parent is | |
1026 | * @td->service_queue, @bio is ready to be issued. Put it on its | |
1027 | * bio_lists[] and decrease total number queued. The caller is | |
1028 | * responsible for issuing these bios. | |
1029 | */ | |
1030 | if (parent_tg) { | |
c5cc2070 | 1031 | throtl_add_bio_tg(bio, &tg->qnode_on_parent[rw], parent_tg); |
32ee5bc4 | 1032 | start_parent_slice_with_credit(tg, parent_tg, rw); |
6bc9c2b4 | 1033 | } else { |
c5cc2070 TH |
1034 | throtl_qnode_add_bio(bio, &tg->qnode_on_parent[rw], |
1035 | &parent_sq->queued[rw]); | |
6bc9c2b4 TH |
1036 | BUG_ON(tg->td->nr_queued[rw] <= 0); |
1037 | tg->td->nr_queued[rw]--; | |
1038 | } | |
e43473b7 | 1039 | |
0f3457f6 | 1040 | throtl_trim_slice(tg, rw); |
6bc9c2b4 | 1041 | |
c5cc2070 TH |
1042 | if (tg_to_put) |
1043 | blkg_put(tg_to_blkg(tg_to_put)); | |
e43473b7 VG |
1044 | } |
1045 | ||
77216b04 | 1046 | static int throtl_dispatch_tg(struct throtl_grp *tg) |
e43473b7 | 1047 | { |
73f0d49a | 1048 | struct throtl_service_queue *sq = &tg->service_queue; |
e43473b7 VG |
1049 | unsigned int nr_reads = 0, nr_writes = 0; |
1050 | unsigned int max_nr_reads = throtl_grp_quantum*3/4; | |
c2f6805d | 1051 | unsigned int max_nr_writes = throtl_grp_quantum - max_nr_reads; |
e43473b7 VG |
1052 | struct bio *bio; |
1053 | ||
1054 | /* Try to dispatch 75% READS and 25% WRITES */ | |
1055 | ||
c5cc2070 | 1056 | while ((bio = throtl_peek_queued(&sq->queued[READ])) && |
0f3457f6 | 1057 | tg_may_dispatch(tg, bio, NULL)) { |
e43473b7 | 1058 | |
77216b04 | 1059 | tg_dispatch_one_bio(tg, bio_data_dir(bio)); |
e43473b7 VG |
1060 | nr_reads++; |
1061 | ||
1062 | if (nr_reads >= max_nr_reads) | |
1063 | break; | |
1064 | } | |
1065 | ||
c5cc2070 | 1066 | while ((bio = throtl_peek_queued(&sq->queued[WRITE])) && |
0f3457f6 | 1067 | tg_may_dispatch(tg, bio, NULL)) { |
e43473b7 | 1068 | |
77216b04 | 1069 | tg_dispatch_one_bio(tg, bio_data_dir(bio)); |
e43473b7 VG |
1070 | nr_writes++; |
1071 | ||
1072 | if (nr_writes >= max_nr_writes) | |
1073 | break; | |
1074 | } | |
1075 | ||
1076 | return nr_reads + nr_writes; | |
1077 | } | |
1078 | ||
651930bc | 1079 | static int throtl_select_dispatch(struct throtl_service_queue *parent_sq) |
e43473b7 VG |
1080 | { |
1081 | unsigned int nr_disp = 0; | |
e43473b7 VG |
1082 | |
1083 | while (1) { | |
73f0d49a TH |
1084 | struct throtl_grp *tg = throtl_rb_first(parent_sq); |
1085 | struct throtl_service_queue *sq = &tg->service_queue; | |
e43473b7 VG |
1086 | |
1087 | if (!tg) | |
1088 | break; | |
1089 | ||
1090 | if (time_before(jiffies, tg->disptime)) | |
1091 | break; | |
1092 | ||
77216b04 | 1093 | throtl_dequeue_tg(tg); |
e43473b7 | 1094 | |
77216b04 | 1095 | nr_disp += throtl_dispatch_tg(tg); |
e43473b7 | 1096 | |
73f0d49a | 1097 | if (sq->nr_queued[0] || sq->nr_queued[1]) |
77216b04 | 1098 | tg_update_disptime(tg); |
e43473b7 VG |
1099 | |
1100 | if (nr_disp >= throtl_quantum) | |
1101 | break; | |
1102 | } | |
1103 | ||
1104 | return nr_disp; | |
1105 | } | |
1106 | ||
c79892c5 SL |
1107 | static bool throtl_can_upgrade(struct throtl_data *td, |
1108 | struct throtl_grp *this_tg); | |
6e1a5704 TH |
1109 | /** |
1110 | * throtl_pending_timer_fn - timer function for service_queue->pending_timer | |
1111 | * @arg: the throtl_service_queue being serviced | |
1112 | * | |
1113 | * This timer is armed when a child throtl_grp with active bio's become | |
1114 | * pending and queued on the service_queue's pending_tree and expires when | |
1115 | * the first child throtl_grp should be dispatched. This function | |
2e48a530 TH |
1116 | * dispatches bio's from the children throtl_grps to the parent |
1117 | * service_queue. | |
1118 | * | |
1119 | * If the parent's parent is another throtl_grp, dispatching is propagated | |
1120 | * by either arming its pending_timer or repeating dispatch directly. If | |
1121 | * the top-level service_tree is reached, throtl_data->dispatch_work is | |
1122 | * kicked so that the ready bio's are issued. | |
6e1a5704 | 1123 | */ |
69df0ab0 TH |
1124 | static void throtl_pending_timer_fn(unsigned long arg) |
1125 | { | |
1126 | struct throtl_service_queue *sq = (void *)arg; | |
2e48a530 | 1127 | struct throtl_grp *tg = sq_to_tg(sq); |
69df0ab0 | 1128 | struct throtl_data *td = sq_to_td(sq); |
cb76199c | 1129 | struct request_queue *q = td->queue; |
2e48a530 TH |
1130 | struct throtl_service_queue *parent_sq; |
1131 | bool dispatched; | |
6e1a5704 | 1132 | int ret; |
e43473b7 VG |
1133 | |
1134 | spin_lock_irq(q->queue_lock); | |
c79892c5 SL |
1135 | if (throtl_can_upgrade(td, NULL)) |
1136 | throtl_upgrade_state(td); | |
1137 | ||
2e48a530 TH |
1138 | again: |
1139 | parent_sq = sq->parent_sq; | |
1140 | dispatched = false; | |
e43473b7 | 1141 | |
7f52f98c TH |
1142 | while (true) { |
1143 | throtl_log(sq, "dispatch nr_queued=%u read=%u write=%u", | |
2e48a530 TH |
1144 | sq->nr_queued[READ] + sq->nr_queued[WRITE], |
1145 | sq->nr_queued[READ], sq->nr_queued[WRITE]); | |
7f52f98c TH |
1146 | |
1147 | ret = throtl_select_dispatch(sq); | |
1148 | if (ret) { | |
7f52f98c TH |
1149 | throtl_log(sq, "bios disp=%u", ret); |
1150 | dispatched = true; | |
1151 | } | |
e43473b7 | 1152 | |
7f52f98c TH |
1153 | if (throtl_schedule_next_dispatch(sq, false)) |
1154 | break; | |
e43473b7 | 1155 | |
7f52f98c TH |
1156 | /* this dispatch windows is still open, relax and repeat */ |
1157 | spin_unlock_irq(q->queue_lock); | |
1158 | cpu_relax(); | |
1159 | spin_lock_irq(q->queue_lock); | |
651930bc | 1160 | } |
e43473b7 | 1161 | |
2e48a530 TH |
1162 | if (!dispatched) |
1163 | goto out_unlock; | |
6e1a5704 | 1164 | |
2e48a530 TH |
1165 | if (parent_sq) { |
1166 | /* @parent_sq is another throl_grp, propagate dispatch */ | |
1167 | if (tg->flags & THROTL_TG_WAS_EMPTY) { | |
1168 | tg_update_disptime(tg); | |
1169 | if (!throtl_schedule_next_dispatch(parent_sq, false)) { | |
1170 | /* window is already open, repeat dispatching */ | |
1171 | sq = parent_sq; | |
1172 | tg = sq_to_tg(sq); | |
1173 | goto again; | |
1174 | } | |
1175 | } | |
1176 | } else { | |
1177 | /* reached the top-level, queue issueing */ | |
1178 | queue_work(kthrotld_workqueue, &td->dispatch_work); | |
1179 | } | |
1180 | out_unlock: | |
e43473b7 | 1181 | spin_unlock_irq(q->queue_lock); |
6e1a5704 | 1182 | } |
e43473b7 | 1183 | |
6e1a5704 TH |
1184 | /** |
1185 | * blk_throtl_dispatch_work_fn - work function for throtl_data->dispatch_work | |
1186 | * @work: work item being executed | |
1187 | * | |
1188 | * This function is queued for execution when bio's reach the bio_lists[] | |
1189 | * of throtl_data->service_queue. Those bio's are ready and issued by this | |
1190 | * function. | |
1191 | */ | |
8876e140 | 1192 | static void blk_throtl_dispatch_work_fn(struct work_struct *work) |
6e1a5704 TH |
1193 | { |
1194 | struct throtl_data *td = container_of(work, struct throtl_data, | |
1195 | dispatch_work); | |
1196 | struct throtl_service_queue *td_sq = &td->service_queue; | |
1197 | struct request_queue *q = td->queue; | |
1198 | struct bio_list bio_list_on_stack; | |
1199 | struct bio *bio; | |
1200 | struct blk_plug plug; | |
1201 | int rw; | |
1202 | ||
1203 | bio_list_init(&bio_list_on_stack); | |
1204 | ||
1205 | spin_lock_irq(q->queue_lock); | |
c5cc2070 TH |
1206 | for (rw = READ; rw <= WRITE; rw++) |
1207 | while ((bio = throtl_pop_queued(&td_sq->queued[rw], NULL))) | |
1208 | bio_list_add(&bio_list_on_stack, bio); | |
6e1a5704 TH |
1209 | spin_unlock_irq(q->queue_lock); |
1210 | ||
1211 | if (!bio_list_empty(&bio_list_on_stack)) { | |
69d60eb9 | 1212 | blk_start_plug(&plug); |
e43473b7 VG |
1213 | while((bio = bio_list_pop(&bio_list_on_stack))) |
1214 | generic_make_request(bio); | |
69d60eb9 | 1215 | blk_finish_plug(&plug); |
e43473b7 | 1216 | } |
e43473b7 VG |
1217 | } |
1218 | ||
f95a04af TH |
1219 | static u64 tg_prfill_conf_u64(struct seq_file *sf, struct blkg_policy_data *pd, |
1220 | int off) | |
60c2bc2d | 1221 | { |
f95a04af TH |
1222 | struct throtl_grp *tg = pd_to_tg(pd); |
1223 | u64 v = *(u64 *)((void *)tg + off); | |
60c2bc2d | 1224 | |
2ab5492d | 1225 | if (v == U64_MAX) |
60c2bc2d | 1226 | return 0; |
f95a04af | 1227 | return __blkg_prfill_u64(sf, pd, v); |
60c2bc2d TH |
1228 | } |
1229 | ||
f95a04af TH |
1230 | static u64 tg_prfill_conf_uint(struct seq_file *sf, struct blkg_policy_data *pd, |
1231 | int off) | |
e43473b7 | 1232 | { |
f95a04af TH |
1233 | struct throtl_grp *tg = pd_to_tg(pd); |
1234 | unsigned int v = *(unsigned int *)((void *)tg + off); | |
fe071437 | 1235 | |
2ab5492d | 1236 | if (v == UINT_MAX) |
af133ceb | 1237 | return 0; |
f95a04af | 1238 | return __blkg_prfill_u64(sf, pd, v); |
e43473b7 VG |
1239 | } |
1240 | ||
2da8ca82 | 1241 | static int tg_print_conf_u64(struct seq_file *sf, void *v) |
8e89d13f | 1242 | { |
2da8ca82 TH |
1243 | blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), tg_prfill_conf_u64, |
1244 | &blkcg_policy_throtl, seq_cft(sf)->private, false); | |
af133ceb | 1245 | return 0; |
8e89d13f VG |
1246 | } |
1247 | ||
2da8ca82 | 1248 | static int tg_print_conf_uint(struct seq_file *sf, void *v) |
8e89d13f | 1249 | { |
2da8ca82 TH |
1250 | blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), tg_prfill_conf_uint, |
1251 | &blkcg_policy_throtl, seq_cft(sf)->private, false); | |
af133ceb | 1252 | return 0; |
60c2bc2d TH |
1253 | } |
1254 | ||
69948b07 | 1255 | static void tg_conf_updated(struct throtl_grp *tg) |
60c2bc2d | 1256 | { |
69948b07 | 1257 | struct throtl_service_queue *sq = &tg->service_queue; |
492eb21b | 1258 | struct cgroup_subsys_state *pos_css; |
69948b07 | 1259 | struct blkcg_gq *blkg; |
af133ceb | 1260 | |
fda6f272 TH |
1261 | throtl_log(&tg->service_queue, |
1262 | "limit change rbps=%llu wbps=%llu riops=%u wiops=%u", | |
9f626e37 SL |
1263 | tg_bps_limit(tg, READ), tg_bps_limit(tg, WRITE), |
1264 | tg_iops_limit(tg, READ), tg_iops_limit(tg, WRITE)); | |
632b4493 | 1265 | |
693e751e TH |
1266 | /* |
1267 | * Update has_rules[] flags for the updated tg's subtree. A tg is | |
1268 | * considered to have rules if either the tg itself or any of its | |
1269 | * ancestors has rules. This identifies groups without any | |
1270 | * restrictions in the whole hierarchy and allows them to bypass | |
1271 | * blk-throttle. | |
1272 | */ | |
69948b07 | 1273 | blkg_for_each_descendant_pre(blkg, pos_css, tg_to_blkg(tg)) |
693e751e TH |
1274 | tg_update_has_rules(blkg_to_tg(blkg)); |
1275 | ||
632b4493 TH |
1276 | /* |
1277 | * We're already holding queue_lock and know @tg is valid. Let's | |
1278 | * apply the new config directly. | |
1279 | * | |
1280 | * Restart the slices for both READ and WRITES. It might happen | |
1281 | * that a group's limit are dropped suddenly and we don't want to | |
1282 | * account recently dispatched IO with new low rate. | |
1283 | */ | |
0f3457f6 TH |
1284 | throtl_start_new_slice(tg, 0); |
1285 | throtl_start_new_slice(tg, 1); | |
632b4493 | 1286 | |
5b2c16aa | 1287 | if (tg->flags & THROTL_TG_PENDING) { |
77216b04 | 1288 | tg_update_disptime(tg); |
7f52f98c | 1289 | throtl_schedule_next_dispatch(sq->parent_sq, true); |
632b4493 | 1290 | } |
69948b07 TH |
1291 | } |
1292 | ||
1293 | static ssize_t tg_set_conf(struct kernfs_open_file *of, | |
1294 | char *buf, size_t nbytes, loff_t off, bool is_u64) | |
1295 | { | |
1296 | struct blkcg *blkcg = css_to_blkcg(of_css(of)); | |
1297 | struct blkg_conf_ctx ctx; | |
1298 | struct throtl_grp *tg; | |
1299 | int ret; | |
1300 | u64 v; | |
1301 | ||
1302 | ret = blkg_conf_prep(blkcg, &blkcg_policy_throtl, buf, &ctx); | |
1303 | if (ret) | |
1304 | return ret; | |
1305 | ||
1306 | ret = -EINVAL; | |
1307 | if (sscanf(ctx.body, "%llu", &v) != 1) | |
1308 | goto out_finish; | |
1309 | if (!v) | |
2ab5492d | 1310 | v = U64_MAX; |
69948b07 TH |
1311 | |
1312 | tg = blkg_to_tg(ctx.blkg); | |
1313 | ||
1314 | if (is_u64) | |
1315 | *(u64 *)((void *)tg + of_cft(of)->private) = v; | |
1316 | else | |
1317 | *(unsigned int *)((void *)tg + of_cft(of)->private) = v; | |
60c2bc2d | 1318 | |
69948b07 | 1319 | tg_conf_updated(tg); |
36aa9e5f TH |
1320 | ret = 0; |
1321 | out_finish: | |
60c2bc2d | 1322 | blkg_conf_finish(&ctx); |
36aa9e5f | 1323 | return ret ?: nbytes; |
8e89d13f VG |
1324 | } |
1325 | ||
451af504 TH |
1326 | static ssize_t tg_set_conf_u64(struct kernfs_open_file *of, |
1327 | char *buf, size_t nbytes, loff_t off) | |
60c2bc2d | 1328 | { |
451af504 | 1329 | return tg_set_conf(of, buf, nbytes, off, true); |
60c2bc2d TH |
1330 | } |
1331 | ||
451af504 TH |
1332 | static ssize_t tg_set_conf_uint(struct kernfs_open_file *of, |
1333 | char *buf, size_t nbytes, loff_t off) | |
60c2bc2d | 1334 | { |
451af504 | 1335 | return tg_set_conf(of, buf, nbytes, off, false); |
60c2bc2d TH |
1336 | } |
1337 | ||
880f50e2 | 1338 | static struct cftype throtl_legacy_files[] = { |
60c2bc2d TH |
1339 | { |
1340 | .name = "throttle.read_bps_device", | |
9f626e37 | 1341 | .private = offsetof(struct throtl_grp, bps[READ][LIMIT_MAX]), |
2da8ca82 | 1342 | .seq_show = tg_print_conf_u64, |
451af504 | 1343 | .write = tg_set_conf_u64, |
60c2bc2d TH |
1344 | }, |
1345 | { | |
1346 | .name = "throttle.write_bps_device", | |
9f626e37 | 1347 | .private = offsetof(struct throtl_grp, bps[WRITE][LIMIT_MAX]), |
2da8ca82 | 1348 | .seq_show = tg_print_conf_u64, |
451af504 | 1349 | .write = tg_set_conf_u64, |
60c2bc2d TH |
1350 | }, |
1351 | { | |
1352 | .name = "throttle.read_iops_device", | |
9f626e37 | 1353 | .private = offsetof(struct throtl_grp, iops[READ][LIMIT_MAX]), |
2da8ca82 | 1354 | .seq_show = tg_print_conf_uint, |
451af504 | 1355 | .write = tg_set_conf_uint, |
60c2bc2d TH |
1356 | }, |
1357 | { | |
1358 | .name = "throttle.write_iops_device", | |
9f626e37 | 1359 | .private = offsetof(struct throtl_grp, iops[WRITE][LIMIT_MAX]), |
2da8ca82 | 1360 | .seq_show = tg_print_conf_uint, |
451af504 | 1361 | .write = tg_set_conf_uint, |
60c2bc2d TH |
1362 | }, |
1363 | { | |
1364 | .name = "throttle.io_service_bytes", | |
77ea7338 TH |
1365 | .private = (unsigned long)&blkcg_policy_throtl, |
1366 | .seq_show = blkg_print_stat_bytes, | |
60c2bc2d TH |
1367 | }, |
1368 | { | |
1369 | .name = "throttle.io_serviced", | |
77ea7338 TH |
1370 | .private = (unsigned long)&blkcg_policy_throtl, |
1371 | .seq_show = blkg_print_stat_ios, | |
60c2bc2d TH |
1372 | }, |
1373 | { } /* terminate */ | |
1374 | }; | |
1375 | ||
cd5ab1b0 | 1376 | static u64 tg_prfill_limit(struct seq_file *sf, struct blkg_policy_data *pd, |
2ee867dc TH |
1377 | int off) |
1378 | { | |
1379 | struct throtl_grp *tg = pd_to_tg(pd); | |
1380 | const char *dname = blkg_dev_name(pd->blkg); | |
1381 | char bufs[4][21] = { "max", "max", "max", "max" }; | |
cd5ab1b0 SL |
1382 | u64 bps_dft; |
1383 | unsigned int iops_dft; | |
2ee867dc TH |
1384 | |
1385 | if (!dname) | |
1386 | return 0; | |
9f626e37 | 1387 | |
cd5ab1b0 SL |
1388 | if (off == LIMIT_LOW) { |
1389 | bps_dft = 0; | |
1390 | iops_dft = 0; | |
1391 | } else { | |
1392 | bps_dft = U64_MAX; | |
1393 | iops_dft = UINT_MAX; | |
1394 | } | |
1395 | ||
1396 | if (tg->bps_conf[READ][off] == bps_dft && | |
1397 | tg->bps_conf[WRITE][off] == bps_dft && | |
1398 | tg->iops_conf[READ][off] == iops_dft && | |
1399 | tg->iops_conf[WRITE][off] == iops_dft) | |
2ee867dc TH |
1400 | return 0; |
1401 | ||
cd5ab1b0 | 1402 | if (tg->bps_conf[READ][off] != bps_dft) |
9f626e37 | 1403 | snprintf(bufs[0], sizeof(bufs[0]), "%llu", |
cd5ab1b0 SL |
1404 | tg->bps_conf[READ][off]); |
1405 | if (tg->bps_conf[WRITE][off] != bps_dft) | |
9f626e37 | 1406 | snprintf(bufs[1], sizeof(bufs[1]), "%llu", |
cd5ab1b0 SL |
1407 | tg->bps_conf[WRITE][off]); |
1408 | if (tg->iops_conf[READ][off] != iops_dft) | |
9f626e37 | 1409 | snprintf(bufs[2], sizeof(bufs[2]), "%u", |
cd5ab1b0 SL |
1410 | tg->iops_conf[READ][off]); |
1411 | if (tg->iops_conf[WRITE][off] != iops_dft) | |
9f626e37 | 1412 | snprintf(bufs[3], sizeof(bufs[3]), "%u", |
cd5ab1b0 | 1413 | tg->iops_conf[WRITE][off]); |
2ee867dc TH |
1414 | |
1415 | seq_printf(sf, "%s rbps=%s wbps=%s riops=%s wiops=%s\n", | |
1416 | dname, bufs[0], bufs[1], bufs[2], bufs[3]); | |
1417 | return 0; | |
1418 | } | |
1419 | ||
cd5ab1b0 | 1420 | static int tg_print_limit(struct seq_file *sf, void *v) |
2ee867dc | 1421 | { |
cd5ab1b0 | 1422 | blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), tg_prfill_limit, |
2ee867dc TH |
1423 | &blkcg_policy_throtl, seq_cft(sf)->private, false); |
1424 | return 0; | |
1425 | } | |
1426 | ||
cd5ab1b0 | 1427 | static ssize_t tg_set_limit(struct kernfs_open_file *of, |
2ee867dc TH |
1428 | char *buf, size_t nbytes, loff_t off) |
1429 | { | |
1430 | struct blkcg *blkcg = css_to_blkcg(of_css(of)); | |
1431 | struct blkg_conf_ctx ctx; | |
1432 | struct throtl_grp *tg; | |
1433 | u64 v[4]; | |
1434 | int ret; | |
cd5ab1b0 | 1435 | int index = of_cft(of)->private; |
2ee867dc TH |
1436 | |
1437 | ret = blkg_conf_prep(blkcg, &blkcg_policy_throtl, buf, &ctx); | |
1438 | if (ret) | |
1439 | return ret; | |
1440 | ||
1441 | tg = blkg_to_tg(ctx.blkg); | |
1442 | ||
cd5ab1b0 SL |
1443 | v[0] = tg->bps_conf[READ][index]; |
1444 | v[1] = tg->bps_conf[WRITE][index]; | |
1445 | v[2] = tg->iops_conf[READ][index]; | |
1446 | v[3] = tg->iops_conf[WRITE][index]; | |
2ee867dc TH |
1447 | |
1448 | while (true) { | |
1449 | char tok[27]; /* wiops=18446744073709551616 */ | |
1450 | char *p; | |
2ab5492d | 1451 | u64 val = U64_MAX; |
2ee867dc TH |
1452 | int len; |
1453 | ||
1454 | if (sscanf(ctx.body, "%26s%n", tok, &len) != 1) | |
1455 | break; | |
1456 | if (tok[0] == '\0') | |
1457 | break; | |
1458 | ctx.body += len; | |
1459 | ||
1460 | ret = -EINVAL; | |
1461 | p = tok; | |
1462 | strsep(&p, "="); | |
1463 | if (!p || (sscanf(p, "%llu", &val) != 1 && strcmp(p, "max"))) | |
1464 | goto out_finish; | |
1465 | ||
1466 | ret = -ERANGE; | |
1467 | if (!val) | |
1468 | goto out_finish; | |
1469 | ||
1470 | ret = -EINVAL; | |
1471 | if (!strcmp(tok, "rbps")) | |
1472 | v[0] = val; | |
1473 | else if (!strcmp(tok, "wbps")) | |
1474 | v[1] = val; | |
1475 | else if (!strcmp(tok, "riops")) | |
1476 | v[2] = min_t(u64, val, UINT_MAX); | |
1477 | else if (!strcmp(tok, "wiops")) | |
1478 | v[3] = min_t(u64, val, UINT_MAX); | |
1479 | else | |
1480 | goto out_finish; | |
1481 | } | |
1482 | ||
cd5ab1b0 SL |
1483 | tg->bps_conf[READ][index] = v[0]; |
1484 | tg->bps_conf[WRITE][index] = v[1]; | |
1485 | tg->iops_conf[READ][index] = v[2]; | |
1486 | tg->iops_conf[WRITE][index] = v[3]; | |
2ee867dc | 1487 | |
cd5ab1b0 SL |
1488 | if (index == LIMIT_MAX) { |
1489 | tg->bps[READ][index] = v[0]; | |
1490 | tg->bps[WRITE][index] = v[1]; | |
1491 | tg->iops[READ][index] = v[2]; | |
1492 | tg->iops[WRITE][index] = v[3]; | |
1493 | } | |
1494 | tg->bps[READ][LIMIT_LOW] = min(tg->bps_conf[READ][LIMIT_LOW], | |
1495 | tg->bps_conf[READ][LIMIT_MAX]); | |
1496 | tg->bps[WRITE][LIMIT_LOW] = min(tg->bps_conf[WRITE][LIMIT_LOW], | |
1497 | tg->bps_conf[WRITE][LIMIT_MAX]); | |
1498 | tg->iops[READ][LIMIT_LOW] = min(tg->iops_conf[READ][LIMIT_LOW], | |
1499 | tg->iops_conf[READ][LIMIT_MAX]); | |
1500 | tg->iops[WRITE][LIMIT_LOW] = min(tg->iops_conf[WRITE][LIMIT_LOW], | |
1501 | tg->iops_conf[WRITE][LIMIT_MAX]); | |
1502 | ||
1503 | if (index == LIMIT_LOW) { | |
1504 | blk_throtl_update_limit_valid(tg->td); | |
1505 | if (tg->td->limit_valid[LIMIT_LOW]) | |
1506 | tg->td->limit_index = LIMIT_LOW; | |
1507 | } | |
2ee867dc TH |
1508 | tg_conf_updated(tg); |
1509 | ret = 0; | |
1510 | out_finish: | |
1511 | blkg_conf_finish(&ctx); | |
1512 | return ret ?: nbytes; | |
1513 | } | |
1514 | ||
1515 | static struct cftype throtl_files[] = { | |
cd5ab1b0 SL |
1516 | #ifdef CONFIG_BLK_DEV_THROTTLING_LOW |
1517 | { | |
1518 | .name = "low", | |
1519 | .flags = CFTYPE_NOT_ON_ROOT, | |
1520 | .seq_show = tg_print_limit, | |
1521 | .write = tg_set_limit, | |
1522 | .private = LIMIT_LOW, | |
1523 | }, | |
1524 | #endif | |
2ee867dc TH |
1525 | { |
1526 | .name = "max", | |
1527 | .flags = CFTYPE_NOT_ON_ROOT, | |
cd5ab1b0 SL |
1528 | .seq_show = tg_print_limit, |
1529 | .write = tg_set_limit, | |
1530 | .private = LIMIT_MAX, | |
2ee867dc TH |
1531 | }, |
1532 | { } /* terminate */ | |
1533 | }; | |
1534 | ||
da527770 | 1535 | static void throtl_shutdown_wq(struct request_queue *q) |
e43473b7 VG |
1536 | { |
1537 | struct throtl_data *td = q->td; | |
1538 | ||
69df0ab0 | 1539 | cancel_work_sync(&td->dispatch_work); |
e43473b7 VG |
1540 | } |
1541 | ||
3c798398 | 1542 | static struct blkcg_policy blkcg_policy_throtl = { |
2ee867dc | 1543 | .dfl_cftypes = throtl_files, |
880f50e2 | 1544 | .legacy_cftypes = throtl_legacy_files, |
f9fcc2d3 | 1545 | |
001bea73 | 1546 | .pd_alloc_fn = throtl_pd_alloc, |
f9fcc2d3 | 1547 | .pd_init_fn = throtl_pd_init, |
693e751e | 1548 | .pd_online_fn = throtl_pd_online, |
cd5ab1b0 | 1549 | .pd_offline_fn = throtl_pd_offline, |
001bea73 | 1550 | .pd_free_fn = throtl_pd_free, |
e43473b7 VG |
1551 | }; |
1552 | ||
3f0abd80 SL |
1553 | static unsigned long __tg_last_low_overflow_time(struct throtl_grp *tg) |
1554 | { | |
1555 | unsigned long rtime = jiffies, wtime = jiffies; | |
1556 | ||
1557 | if (tg->bps[READ][LIMIT_LOW] || tg->iops[READ][LIMIT_LOW]) | |
1558 | rtime = tg->last_low_overflow_time[READ]; | |
1559 | if (tg->bps[WRITE][LIMIT_LOW] || tg->iops[WRITE][LIMIT_LOW]) | |
1560 | wtime = tg->last_low_overflow_time[WRITE]; | |
1561 | return min(rtime, wtime); | |
1562 | } | |
1563 | ||
1564 | /* tg should not be an intermediate node */ | |
1565 | static unsigned long tg_last_low_overflow_time(struct throtl_grp *tg) | |
1566 | { | |
1567 | struct throtl_service_queue *parent_sq; | |
1568 | struct throtl_grp *parent = tg; | |
1569 | unsigned long ret = __tg_last_low_overflow_time(tg); | |
1570 | ||
1571 | while (true) { | |
1572 | parent_sq = parent->service_queue.parent_sq; | |
1573 | parent = sq_to_tg(parent_sq); | |
1574 | if (!parent) | |
1575 | break; | |
1576 | ||
1577 | /* | |
1578 | * The parent doesn't have low limit, it always reaches low | |
1579 | * limit. Its overflow time is useless for children | |
1580 | */ | |
1581 | if (!parent->bps[READ][LIMIT_LOW] && | |
1582 | !parent->iops[READ][LIMIT_LOW] && | |
1583 | !parent->bps[WRITE][LIMIT_LOW] && | |
1584 | !parent->iops[WRITE][LIMIT_LOW]) | |
1585 | continue; | |
1586 | if (time_after(__tg_last_low_overflow_time(parent), ret)) | |
1587 | ret = __tg_last_low_overflow_time(parent); | |
1588 | } | |
1589 | return ret; | |
1590 | } | |
1591 | ||
c79892c5 SL |
1592 | static bool throtl_tg_can_upgrade(struct throtl_grp *tg) |
1593 | { | |
1594 | struct throtl_service_queue *sq = &tg->service_queue; | |
1595 | bool read_limit, write_limit; | |
1596 | ||
1597 | /* | |
1598 | * if cgroup reaches low limit (if low limit is 0, the cgroup always | |
1599 | * reaches), it's ok to upgrade to next limit | |
1600 | */ | |
1601 | read_limit = tg->bps[READ][LIMIT_LOW] || tg->iops[READ][LIMIT_LOW]; | |
1602 | write_limit = tg->bps[WRITE][LIMIT_LOW] || tg->iops[WRITE][LIMIT_LOW]; | |
1603 | if (!read_limit && !write_limit) | |
1604 | return true; | |
1605 | if (read_limit && sq->nr_queued[READ] && | |
1606 | (!write_limit || sq->nr_queued[WRITE])) | |
1607 | return true; | |
1608 | if (write_limit && sq->nr_queued[WRITE] && | |
1609 | (!read_limit || sq->nr_queued[READ])) | |
1610 | return true; | |
1611 | return false; | |
1612 | } | |
1613 | ||
1614 | static bool throtl_hierarchy_can_upgrade(struct throtl_grp *tg) | |
1615 | { | |
1616 | while (true) { | |
1617 | if (throtl_tg_can_upgrade(tg)) | |
1618 | return true; | |
1619 | tg = sq_to_tg(tg->service_queue.parent_sq); | |
1620 | if (!tg || !tg_to_blkg(tg)->parent) | |
1621 | return false; | |
1622 | } | |
1623 | return false; | |
1624 | } | |
1625 | ||
1626 | static bool throtl_can_upgrade(struct throtl_data *td, | |
1627 | struct throtl_grp *this_tg) | |
1628 | { | |
1629 | struct cgroup_subsys_state *pos_css; | |
1630 | struct blkcg_gq *blkg; | |
1631 | ||
1632 | if (td->limit_index != LIMIT_LOW) | |
1633 | return false; | |
1634 | ||
3f0abd80 SL |
1635 | if (time_before(jiffies, td->low_downgrade_time + throtl_slice)) |
1636 | return false; | |
1637 | ||
c79892c5 SL |
1638 | rcu_read_lock(); |
1639 | blkg_for_each_descendant_post(blkg, pos_css, td->queue->root_blkg) { | |
1640 | struct throtl_grp *tg = blkg_to_tg(blkg); | |
1641 | ||
1642 | if (tg == this_tg) | |
1643 | continue; | |
1644 | if (!list_empty(&tg_to_blkg(tg)->blkcg->css.children)) | |
1645 | continue; | |
1646 | if (!throtl_hierarchy_can_upgrade(tg)) { | |
1647 | rcu_read_unlock(); | |
1648 | return false; | |
1649 | } | |
1650 | } | |
1651 | rcu_read_unlock(); | |
1652 | return true; | |
1653 | } | |
1654 | ||
1655 | static void throtl_upgrade_state(struct throtl_data *td) | |
1656 | { | |
1657 | struct cgroup_subsys_state *pos_css; | |
1658 | struct blkcg_gq *blkg; | |
1659 | ||
1660 | td->limit_index = LIMIT_MAX; | |
3f0abd80 | 1661 | td->low_upgrade_time = jiffies; |
c79892c5 SL |
1662 | rcu_read_lock(); |
1663 | blkg_for_each_descendant_post(blkg, pos_css, td->queue->root_blkg) { | |
1664 | struct throtl_grp *tg = blkg_to_tg(blkg); | |
1665 | struct throtl_service_queue *sq = &tg->service_queue; | |
1666 | ||
1667 | tg->disptime = jiffies - 1; | |
1668 | throtl_select_dispatch(sq); | |
1669 | throtl_schedule_next_dispatch(sq, false); | |
1670 | } | |
1671 | rcu_read_unlock(); | |
1672 | throtl_select_dispatch(&td->service_queue); | |
1673 | throtl_schedule_next_dispatch(&td->service_queue, false); | |
1674 | queue_work(kthrotld_workqueue, &td->dispatch_work); | |
1675 | } | |
1676 | ||
3f0abd80 SL |
1677 | static void throtl_downgrade_state(struct throtl_data *td, int new) |
1678 | { | |
1679 | td->limit_index = new; | |
1680 | td->low_downgrade_time = jiffies; | |
1681 | } | |
1682 | ||
1683 | static bool throtl_tg_can_downgrade(struct throtl_grp *tg) | |
1684 | { | |
1685 | struct throtl_data *td = tg->td; | |
1686 | unsigned long now = jiffies; | |
1687 | ||
1688 | /* | |
1689 | * If cgroup is below low limit, consider downgrade and throttle other | |
1690 | * cgroups | |
1691 | */ | |
1692 | if (time_after_eq(now, td->low_upgrade_time + throtl_slice) && | |
1693 | time_after_eq(now, tg_last_low_overflow_time(tg) + throtl_slice)) | |
1694 | return true; | |
1695 | return false; | |
1696 | } | |
1697 | ||
1698 | static bool throtl_hierarchy_can_downgrade(struct throtl_grp *tg) | |
1699 | { | |
1700 | while (true) { | |
1701 | if (!throtl_tg_can_downgrade(tg)) | |
1702 | return false; | |
1703 | tg = sq_to_tg(tg->service_queue.parent_sq); | |
1704 | if (!tg || !tg_to_blkg(tg)->parent) | |
1705 | break; | |
1706 | } | |
1707 | return true; | |
1708 | } | |
1709 | ||
1710 | static void throtl_downgrade_check(struct throtl_grp *tg) | |
1711 | { | |
1712 | uint64_t bps; | |
1713 | unsigned int iops; | |
1714 | unsigned long elapsed_time; | |
1715 | unsigned long now = jiffies; | |
1716 | ||
1717 | if (tg->td->limit_index != LIMIT_MAX || | |
1718 | !tg->td->limit_valid[LIMIT_LOW]) | |
1719 | return; | |
1720 | if (!list_empty(&tg_to_blkg(tg)->blkcg->css.children)) | |
1721 | return; | |
1722 | if (time_after(tg->last_check_time + throtl_slice, now)) | |
1723 | return; | |
1724 | ||
1725 | elapsed_time = now - tg->last_check_time; | |
1726 | tg->last_check_time = now; | |
1727 | ||
1728 | if (time_before(now, tg_last_low_overflow_time(tg) + throtl_slice)) | |
1729 | return; | |
1730 | ||
1731 | if (tg->bps[READ][LIMIT_LOW]) { | |
1732 | bps = tg->last_bytes_disp[READ] * HZ; | |
1733 | do_div(bps, elapsed_time); | |
1734 | if (bps >= tg->bps[READ][LIMIT_LOW]) | |
1735 | tg->last_low_overflow_time[READ] = now; | |
1736 | } | |
1737 | ||
1738 | if (tg->bps[WRITE][LIMIT_LOW]) { | |
1739 | bps = tg->last_bytes_disp[WRITE] * HZ; | |
1740 | do_div(bps, elapsed_time); | |
1741 | if (bps >= tg->bps[WRITE][LIMIT_LOW]) | |
1742 | tg->last_low_overflow_time[WRITE] = now; | |
1743 | } | |
1744 | ||
1745 | if (tg->iops[READ][LIMIT_LOW]) { | |
1746 | iops = tg->last_io_disp[READ] * HZ / elapsed_time; | |
1747 | if (iops >= tg->iops[READ][LIMIT_LOW]) | |
1748 | tg->last_low_overflow_time[READ] = now; | |
1749 | } | |
1750 | ||
1751 | if (tg->iops[WRITE][LIMIT_LOW]) { | |
1752 | iops = tg->last_io_disp[WRITE] * HZ / elapsed_time; | |
1753 | if (iops >= tg->iops[WRITE][LIMIT_LOW]) | |
1754 | tg->last_low_overflow_time[WRITE] = now; | |
1755 | } | |
1756 | ||
1757 | /* | |
1758 | * If cgroup is below low limit, consider downgrade and throttle other | |
1759 | * cgroups | |
1760 | */ | |
1761 | if (throtl_hierarchy_can_downgrade(tg)) | |
1762 | throtl_downgrade_state(tg->td, LIMIT_LOW); | |
1763 | ||
1764 | tg->last_bytes_disp[READ] = 0; | |
1765 | tg->last_bytes_disp[WRITE] = 0; | |
1766 | tg->last_io_disp[READ] = 0; | |
1767 | tg->last_io_disp[WRITE] = 0; | |
1768 | } | |
1769 | ||
ae118896 TH |
1770 | bool blk_throtl_bio(struct request_queue *q, struct blkcg_gq *blkg, |
1771 | struct bio *bio) | |
e43473b7 | 1772 | { |
c5cc2070 | 1773 | struct throtl_qnode *qn = NULL; |
ae118896 | 1774 | struct throtl_grp *tg = blkg_to_tg(blkg ?: q->root_blkg); |
73f0d49a | 1775 | struct throtl_service_queue *sq; |
0e9f4164 | 1776 | bool rw = bio_data_dir(bio); |
bc16a4f9 | 1777 | bool throttled = false; |
e43473b7 | 1778 | |
ae118896 TH |
1779 | WARN_ON_ONCE(!rcu_read_lock_held()); |
1780 | ||
2a0f61e6 | 1781 | /* see throtl_charge_bio() */ |
8d2bbd4c | 1782 | if (bio_flagged(bio, BIO_THROTTLED) || !tg->has_rules[rw]) |
bc16a4f9 | 1783 | goto out; |
e43473b7 VG |
1784 | |
1785 | spin_lock_irq(q->queue_lock); | |
c9589f03 TH |
1786 | |
1787 | if (unlikely(blk_queue_bypass(q))) | |
bc16a4f9 | 1788 | goto out_unlock; |
f469a7b4 | 1789 | |
73f0d49a TH |
1790 | sq = &tg->service_queue; |
1791 | ||
c79892c5 | 1792 | again: |
9e660acf | 1793 | while (true) { |
3f0abd80 SL |
1794 | if (tg->last_low_overflow_time[rw] == 0) |
1795 | tg->last_low_overflow_time[rw] = jiffies; | |
1796 | throtl_downgrade_check(tg); | |
9e660acf TH |
1797 | /* throtl is FIFO - if bios are already queued, should queue */ |
1798 | if (sq->nr_queued[rw]) | |
1799 | break; | |
de701c74 | 1800 | |
9e660acf | 1801 | /* if above limits, break to queue */ |
c79892c5 | 1802 | if (!tg_may_dispatch(tg, bio, NULL)) { |
3f0abd80 | 1803 | tg->last_low_overflow_time[rw] = jiffies; |
c79892c5 SL |
1804 | if (throtl_can_upgrade(tg->td, tg)) { |
1805 | throtl_upgrade_state(tg->td); | |
1806 | goto again; | |
1807 | } | |
9e660acf | 1808 | break; |
c79892c5 | 1809 | } |
9e660acf TH |
1810 | |
1811 | /* within limits, let's charge and dispatch directly */ | |
e43473b7 | 1812 | throtl_charge_bio(tg, bio); |
04521db0 VG |
1813 | |
1814 | /* | |
1815 | * We need to trim slice even when bios are not being queued | |
1816 | * otherwise it might happen that a bio is not queued for | |
1817 | * a long time and slice keeps on extending and trim is not | |
1818 | * called for a long time. Now if limits are reduced suddenly | |
1819 | * we take into account all the IO dispatched so far at new | |
1820 | * low rate and * newly queued IO gets a really long dispatch | |
1821 | * time. | |
1822 | * | |
1823 | * So keep on trimming slice even if bio is not queued. | |
1824 | */ | |
0f3457f6 | 1825 | throtl_trim_slice(tg, rw); |
9e660acf TH |
1826 | |
1827 | /* | |
1828 | * @bio passed through this layer without being throttled. | |
1829 | * Climb up the ladder. If we''re already at the top, it | |
1830 | * can be executed directly. | |
1831 | */ | |
c5cc2070 | 1832 | qn = &tg->qnode_on_parent[rw]; |
9e660acf TH |
1833 | sq = sq->parent_sq; |
1834 | tg = sq_to_tg(sq); | |
1835 | if (!tg) | |
1836 | goto out_unlock; | |
e43473b7 VG |
1837 | } |
1838 | ||
9e660acf | 1839 | /* out-of-limit, queue to @tg */ |
fda6f272 TH |
1840 | throtl_log(sq, "[%c] bio. bdisp=%llu sz=%u bps=%llu iodisp=%u iops=%u queued=%d/%d", |
1841 | rw == READ ? 'R' : 'W', | |
9f626e37 SL |
1842 | tg->bytes_disp[rw], bio->bi_iter.bi_size, |
1843 | tg_bps_limit(tg, rw), | |
1844 | tg->io_disp[rw], tg_iops_limit(tg, rw), | |
fda6f272 | 1845 | sq->nr_queued[READ], sq->nr_queued[WRITE]); |
e43473b7 | 1846 | |
3f0abd80 SL |
1847 | tg->last_low_overflow_time[rw] = jiffies; |
1848 | ||
671058fb | 1849 | bio_associate_current(bio); |
6bc9c2b4 | 1850 | tg->td->nr_queued[rw]++; |
c5cc2070 | 1851 | throtl_add_bio_tg(bio, qn, tg); |
bc16a4f9 | 1852 | throttled = true; |
e43473b7 | 1853 | |
7f52f98c TH |
1854 | /* |
1855 | * Update @tg's dispatch time and force schedule dispatch if @tg | |
1856 | * was empty before @bio. The forced scheduling isn't likely to | |
1857 | * cause undue delay as @bio is likely to be dispatched directly if | |
1858 | * its @tg's disptime is not in the future. | |
1859 | */ | |
0e9f4164 | 1860 | if (tg->flags & THROTL_TG_WAS_EMPTY) { |
77216b04 | 1861 | tg_update_disptime(tg); |
7f52f98c | 1862 | throtl_schedule_next_dispatch(tg->service_queue.parent_sq, true); |
e43473b7 VG |
1863 | } |
1864 | ||
bc16a4f9 | 1865 | out_unlock: |
e43473b7 | 1866 | spin_unlock_irq(q->queue_lock); |
bc16a4f9 | 1867 | out: |
2a0f61e6 TH |
1868 | /* |
1869 | * As multiple blk-throtls may stack in the same issue path, we | |
1870 | * don't want bios to leave with the flag set. Clear the flag if | |
1871 | * being issued. | |
1872 | */ | |
1873 | if (!throttled) | |
8d2bbd4c | 1874 | bio_clear_flag(bio, BIO_THROTTLED); |
bc16a4f9 | 1875 | return throttled; |
e43473b7 VG |
1876 | } |
1877 | ||
2a12f0dc TH |
1878 | /* |
1879 | * Dispatch all bios from all children tg's queued on @parent_sq. On | |
1880 | * return, @parent_sq is guaranteed to not have any active children tg's | |
1881 | * and all bios from previously active tg's are on @parent_sq->bio_lists[]. | |
1882 | */ | |
1883 | static void tg_drain_bios(struct throtl_service_queue *parent_sq) | |
1884 | { | |
1885 | struct throtl_grp *tg; | |
1886 | ||
1887 | while ((tg = throtl_rb_first(parent_sq))) { | |
1888 | struct throtl_service_queue *sq = &tg->service_queue; | |
1889 | struct bio *bio; | |
1890 | ||
1891 | throtl_dequeue_tg(tg); | |
1892 | ||
c5cc2070 | 1893 | while ((bio = throtl_peek_queued(&sq->queued[READ]))) |
2a12f0dc | 1894 | tg_dispatch_one_bio(tg, bio_data_dir(bio)); |
c5cc2070 | 1895 | while ((bio = throtl_peek_queued(&sq->queued[WRITE]))) |
2a12f0dc TH |
1896 | tg_dispatch_one_bio(tg, bio_data_dir(bio)); |
1897 | } | |
1898 | } | |
1899 | ||
c9a929dd TH |
1900 | /** |
1901 | * blk_throtl_drain - drain throttled bios | |
1902 | * @q: request_queue to drain throttled bios for | |
1903 | * | |
1904 | * Dispatch all currently throttled bios on @q through ->make_request_fn(). | |
1905 | */ | |
1906 | void blk_throtl_drain(struct request_queue *q) | |
1907 | __releases(q->queue_lock) __acquires(q->queue_lock) | |
1908 | { | |
1909 | struct throtl_data *td = q->td; | |
2a12f0dc | 1910 | struct blkcg_gq *blkg; |
492eb21b | 1911 | struct cgroup_subsys_state *pos_css; |
c9a929dd | 1912 | struct bio *bio; |
651930bc | 1913 | int rw; |
c9a929dd | 1914 | |
8bcb6c7d | 1915 | queue_lockdep_assert_held(q); |
2a12f0dc | 1916 | rcu_read_lock(); |
c9a929dd | 1917 | |
2a12f0dc TH |
1918 | /* |
1919 | * Drain each tg while doing post-order walk on the blkg tree, so | |
1920 | * that all bios are propagated to td->service_queue. It'd be | |
1921 | * better to walk service_queue tree directly but blkg walk is | |
1922 | * easier. | |
1923 | */ | |
492eb21b | 1924 | blkg_for_each_descendant_post(blkg, pos_css, td->queue->root_blkg) |
2a12f0dc | 1925 | tg_drain_bios(&blkg_to_tg(blkg)->service_queue); |
73f0d49a | 1926 | |
2a12f0dc TH |
1927 | /* finally, transfer bios from top-level tg's into the td */ |
1928 | tg_drain_bios(&td->service_queue); | |
1929 | ||
1930 | rcu_read_unlock(); | |
c9a929dd TH |
1931 | spin_unlock_irq(q->queue_lock); |
1932 | ||
2a12f0dc | 1933 | /* all bios now should be in td->service_queue, issue them */ |
651930bc | 1934 | for (rw = READ; rw <= WRITE; rw++) |
c5cc2070 TH |
1935 | while ((bio = throtl_pop_queued(&td->service_queue.queued[rw], |
1936 | NULL))) | |
651930bc | 1937 | generic_make_request(bio); |
c9a929dd TH |
1938 | |
1939 | spin_lock_irq(q->queue_lock); | |
1940 | } | |
1941 | ||
e43473b7 VG |
1942 | int blk_throtl_init(struct request_queue *q) |
1943 | { | |
1944 | struct throtl_data *td; | |
a2b1693b | 1945 | int ret; |
e43473b7 VG |
1946 | |
1947 | td = kzalloc_node(sizeof(*td), GFP_KERNEL, q->node); | |
1948 | if (!td) | |
1949 | return -ENOMEM; | |
1950 | ||
69df0ab0 | 1951 | INIT_WORK(&td->dispatch_work, blk_throtl_dispatch_work_fn); |
b2ce2643 | 1952 | throtl_service_queue_init(&td->service_queue); |
e43473b7 | 1953 | |
cd1604fa | 1954 | q->td = td; |
29b12589 | 1955 | td->queue = q; |
02977e4a | 1956 | |
9f626e37 | 1957 | td->limit_valid[LIMIT_MAX] = true; |
cd5ab1b0 | 1958 | td->limit_index = LIMIT_MAX; |
3f0abd80 SL |
1959 | td->low_upgrade_time = jiffies; |
1960 | td->low_downgrade_time = jiffies; | |
a2b1693b | 1961 | /* activate policy */ |
3c798398 | 1962 | ret = blkcg_activate_policy(q, &blkcg_policy_throtl); |
a2b1693b | 1963 | if (ret) |
f51b802c | 1964 | kfree(td); |
a2b1693b | 1965 | return ret; |
e43473b7 VG |
1966 | } |
1967 | ||
1968 | void blk_throtl_exit(struct request_queue *q) | |
1969 | { | |
c875f4d0 | 1970 | BUG_ON(!q->td); |
da527770 | 1971 | throtl_shutdown_wq(q); |
3c798398 | 1972 | blkcg_deactivate_policy(q, &blkcg_policy_throtl); |
c9a929dd | 1973 | kfree(q->td); |
e43473b7 VG |
1974 | } |
1975 | ||
1976 | static int __init throtl_init(void) | |
1977 | { | |
450adcbe VG |
1978 | kthrotld_workqueue = alloc_workqueue("kthrotld", WQ_MEM_RECLAIM, 0); |
1979 | if (!kthrotld_workqueue) | |
1980 | panic("Failed to create kthrotld\n"); | |
1981 | ||
3c798398 | 1982 | return blkcg_policy_register(&blkcg_policy_throtl); |
e43473b7 VG |
1983 | } |
1984 | ||
1985 | module_init(throtl_init); |