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Commit | Line | Data |
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e43473b7 VG |
1 | /* |
2 | * Interface for controlling IO bandwidth on a request queue | |
3 | * | |
4 | * Copyright (C) 2010 Vivek Goyal <vgoyal@redhat.com> | |
5 | */ | |
6 | ||
7 | #include <linux/module.h> | |
8 | #include <linux/slab.h> | |
9 | #include <linux/blkdev.h> | |
10 | #include <linux/bio.h> | |
11 | #include <linux/blktrace_api.h> | |
eea8f41c | 12 | #include <linux/blk-cgroup.h> |
bc9fcbf9 | 13 | #include "blk.h" |
e43473b7 VG |
14 | |
15 | /* Max dispatch from a group in 1 round */ | |
16 | static int throtl_grp_quantum = 8; | |
17 | ||
18 | /* Total max dispatch from all groups in one round */ | |
19 | static int throtl_quantum = 32; | |
20 | ||
d61fcfa4 SL |
21 | /* Throttling is performed over a slice and after that slice is renewed */ |
22 | #define DFL_THROTL_SLICE_HD (HZ / 10) | |
23 | #define DFL_THROTL_SLICE_SSD (HZ / 50) | |
297e3d85 | 24 | #define MAX_THROTL_SLICE (HZ) |
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 | ||
e43473b7 VG |
152 | /* When did we start a new slice */ |
153 | unsigned long slice_start[2]; | |
154 | unsigned long slice_end[2]; | |
155 | }; | |
156 | ||
157 | struct throtl_data | |
158 | { | |
e43473b7 | 159 | /* service tree for active throtl groups */ |
c9e0332e | 160 | struct throtl_service_queue service_queue; |
e43473b7 | 161 | |
e43473b7 VG |
162 | struct request_queue *queue; |
163 | ||
164 | /* Total Number of queued bios on READ and WRITE lists */ | |
165 | unsigned int nr_queued[2]; | |
166 | ||
297e3d85 SL |
167 | unsigned int throtl_slice; |
168 | ||
e43473b7 | 169 | /* Work for dispatching throttled bios */ |
69df0ab0 | 170 | struct work_struct dispatch_work; |
9f626e37 SL |
171 | unsigned int limit_index; |
172 | bool limit_valid[LIMIT_CNT]; | |
3f0abd80 SL |
173 | |
174 | unsigned long low_upgrade_time; | |
175 | unsigned long low_downgrade_time; | |
e43473b7 VG |
176 | }; |
177 | ||
69df0ab0 TH |
178 | static void throtl_pending_timer_fn(unsigned long arg); |
179 | ||
f95a04af TH |
180 | static inline struct throtl_grp *pd_to_tg(struct blkg_policy_data *pd) |
181 | { | |
182 | return pd ? container_of(pd, struct throtl_grp, pd) : NULL; | |
183 | } | |
184 | ||
3c798398 | 185 | static inline struct throtl_grp *blkg_to_tg(struct blkcg_gq *blkg) |
0381411e | 186 | { |
f95a04af | 187 | return pd_to_tg(blkg_to_pd(blkg, &blkcg_policy_throtl)); |
0381411e TH |
188 | } |
189 | ||
3c798398 | 190 | static inline struct blkcg_gq *tg_to_blkg(struct throtl_grp *tg) |
0381411e | 191 | { |
f95a04af | 192 | return pd_to_blkg(&tg->pd); |
0381411e TH |
193 | } |
194 | ||
fda6f272 TH |
195 | /** |
196 | * sq_to_tg - return the throl_grp the specified service queue belongs to | |
197 | * @sq: the throtl_service_queue of interest | |
198 | * | |
199 | * Return the throtl_grp @sq belongs to. If @sq is the top-level one | |
200 | * embedded in throtl_data, %NULL is returned. | |
201 | */ | |
202 | static struct throtl_grp *sq_to_tg(struct throtl_service_queue *sq) | |
203 | { | |
204 | if (sq && sq->parent_sq) | |
205 | return container_of(sq, struct throtl_grp, service_queue); | |
206 | else | |
207 | return NULL; | |
208 | } | |
209 | ||
210 | /** | |
211 | * sq_to_td - return throtl_data the specified service queue belongs to | |
212 | * @sq: the throtl_service_queue of interest | |
213 | * | |
b43daedc | 214 | * A service_queue can be embedded in either a throtl_grp or throtl_data. |
fda6f272 TH |
215 | * Determine the associated throtl_data accordingly and return it. |
216 | */ | |
217 | static struct throtl_data *sq_to_td(struct throtl_service_queue *sq) | |
218 | { | |
219 | struct throtl_grp *tg = sq_to_tg(sq); | |
220 | ||
221 | if (tg) | |
222 | return tg->td; | |
223 | else | |
224 | return container_of(sq, struct throtl_data, service_queue); | |
225 | } | |
226 | ||
9f626e37 SL |
227 | static uint64_t tg_bps_limit(struct throtl_grp *tg, int rw) |
228 | { | |
b22c417c SL |
229 | struct blkcg_gq *blkg = tg_to_blkg(tg); |
230 | uint64_t ret; | |
231 | ||
232 | if (cgroup_subsys_on_dfl(io_cgrp_subsys) && !blkg->parent) | |
233 | return U64_MAX; | |
234 | ret = tg->bps[rw][tg->td->limit_index]; | |
235 | if (ret == 0 && tg->td->limit_index == LIMIT_LOW) | |
236 | return tg->bps[rw][LIMIT_MAX]; | |
237 | return ret; | |
9f626e37 SL |
238 | } |
239 | ||
240 | static unsigned int tg_iops_limit(struct throtl_grp *tg, int rw) | |
241 | { | |
b22c417c SL |
242 | struct blkcg_gq *blkg = tg_to_blkg(tg); |
243 | unsigned int ret; | |
244 | ||
245 | if (cgroup_subsys_on_dfl(io_cgrp_subsys) && !blkg->parent) | |
246 | return UINT_MAX; | |
247 | ret = tg->iops[rw][tg->td->limit_index]; | |
248 | if (ret == 0 && tg->td->limit_index == LIMIT_LOW) | |
249 | return tg->iops[rw][LIMIT_MAX]; | |
250 | return ret; | |
9f626e37 SL |
251 | } |
252 | ||
fda6f272 TH |
253 | /** |
254 | * throtl_log - log debug message via blktrace | |
255 | * @sq: the service_queue being reported | |
256 | * @fmt: printf format string | |
257 | * @args: printf args | |
258 | * | |
259 | * The messages are prefixed with "throtl BLKG_NAME" if @sq belongs to a | |
260 | * throtl_grp; otherwise, just "throtl". | |
fda6f272 TH |
261 | */ |
262 | #define throtl_log(sq, fmt, args...) do { \ | |
263 | struct throtl_grp *__tg = sq_to_tg((sq)); \ | |
264 | struct throtl_data *__td = sq_to_td((sq)); \ | |
265 | \ | |
266 | (void)__td; \ | |
59fa0224 SL |
267 | if (likely(!blk_trace_note_message_enabled(__td->queue))) \ |
268 | break; \ | |
fda6f272 TH |
269 | if ((__tg)) { \ |
270 | char __pbuf[128]; \ | |
54e7ed12 | 271 | \ |
fda6f272 TH |
272 | blkg_path(tg_to_blkg(__tg), __pbuf, sizeof(__pbuf)); \ |
273 | blk_add_trace_msg(__td->queue, "throtl %s " fmt, __pbuf, ##args); \ | |
274 | } else { \ | |
275 | blk_add_trace_msg(__td->queue, "throtl " fmt, ##args); \ | |
276 | } \ | |
54e7ed12 | 277 | } while (0) |
e43473b7 | 278 | |
c5cc2070 TH |
279 | static void throtl_qnode_init(struct throtl_qnode *qn, struct throtl_grp *tg) |
280 | { | |
281 | INIT_LIST_HEAD(&qn->node); | |
282 | bio_list_init(&qn->bios); | |
283 | qn->tg = tg; | |
284 | } | |
285 | ||
286 | /** | |
287 | * throtl_qnode_add_bio - add a bio to a throtl_qnode and activate it | |
288 | * @bio: bio being added | |
289 | * @qn: qnode to add bio to | |
290 | * @queued: the service_queue->queued[] list @qn belongs to | |
291 | * | |
292 | * Add @bio to @qn and put @qn on @queued if it's not already on. | |
293 | * @qn->tg's reference count is bumped when @qn is activated. See the | |
294 | * comment on top of throtl_qnode definition for details. | |
295 | */ | |
296 | static void throtl_qnode_add_bio(struct bio *bio, struct throtl_qnode *qn, | |
297 | struct list_head *queued) | |
298 | { | |
299 | bio_list_add(&qn->bios, bio); | |
300 | if (list_empty(&qn->node)) { | |
301 | list_add_tail(&qn->node, queued); | |
302 | blkg_get(tg_to_blkg(qn->tg)); | |
303 | } | |
304 | } | |
305 | ||
306 | /** | |
307 | * throtl_peek_queued - peek the first bio on a qnode list | |
308 | * @queued: the qnode list to peek | |
309 | */ | |
310 | static struct bio *throtl_peek_queued(struct list_head *queued) | |
311 | { | |
312 | struct throtl_qnode *qn = list_first_entry(queued, struct throtl_qnode, node); | |
313 | struct bio *bio; | |
314 | ||
315 | if (list_empty(queued)) | |
316 | return NULL; | |
317 | ||
318 | bio = bio_list_peek(&qn->bios); | |
319 | WARN_ON_ONCE(!bio); | |
320 | return bio; | |
321 | } | |
322 | ||
323 | /** | |
324 | * throtl_pop_queued - pop the first bio form a qnode list | |
325 | * @queued: the qnode list to pop a bio from | |
326 | * @tg_to_put: optional out argument for throtl_grp to put | |
327 | * | |
328 | * Pop the first bio from the qnode list @queued. After popping, the first | |
329 | * qnode is removed from @queued if empty or moved to the end of @queued so | |
330 | * that the popping order is round-robin. | |
331 | * | |
332 | * When the first qnode is removed, its associated throtl_grp should be put | |
333 | * too. If @tg_to_put is NULL, this function automatically puts it; | |
334 | * otherwise, *@tg_to_put is set to the throtl_grp to put and the caller is | |
335 | * responsible for putting it. | |
336 | */ | |
337 | static struct bio *throtl_pop_queued(struct list_head *queued, | |
338 | struct throtl_grp **tg_to_put) | |
339 | { | |
340 | struct throtl_qnode *qn = list_first_entry(queued, struct throtl_qnode, node); | |
341 | struct bio *bio; | |
342 | ||
343 | if (list_empty(queued)) | |
344 | return NULL; | |
345 | ||
346 | bio = bio_list_pop(&qn->bios); | |
347 | WARN_ON_ONCE(!bio); | |
348 | ||
349 | if (bio_list_empty(&qn->bios)) { | |
350 | list_del_init(&qn->node); | |
351 | if (tg_to_put) | |
352 | *tg_to_put = qn->tg; | |
353 | else | |
354 | blkg_put(tg_to_blkg(qn->tg)); | |
355 | } else { | |
356 | list_move_tail(&qn->node, queued); | |
357 | } | |
358 | ||
359 | return bio; | |
360 | } | |
361 | ||
49a2f1e3 | 362 | /* init a service_queue, assumes the caller zeroed it */ |
b2ce2643 | 363 | static void throtl_service_queue_init(struct throtl_service_queue *sq) |
49a2f1e3 | 364 | { |
c5cc2070 TH |
365 | INIT_LIST_HEAD(&sq->queued[0]); |
366 | INIT_LIST_HEAD(&sq->queued[1]); | |
49a2f1e3 | 367 | sq->pending_tree = RB_ROOT; |
69df0ab0 TH |
368 | setup_timer(&sq->pending_timer, throtl_pending_timer_fn, |
369 | (unsigned long)sq); | |
370 | } | |
371 | ||
001bea73 TH |
372 | static struct blkg_policy_data *throtl_pd_alloc(gfp_t gfp, int node) |
373 | { | |
4fb72036 | 374 | struct throtl_grp *tg; |
24bdb8ef | 375 | int rw; |
4fb72036 TH |
376 | |
377 | tg = kzalloc_node(sizeof(*tg), gfp, node); | |
378 | if (!tg) | |
77ea7338 | 379 | return NULL; |
4fb72036 | 380 | |
b2ce2643 TH |
381 | throtl_service_queue_init(&tg->service_queue); |
382 | ||
383 | for (rw = READ; rw <= WRITE; rw++) { | |
384 | throtl_qnode_init(&tg->qnode_on_self[rw], tg); | |
385 | throtl_qnode_init(&tg->qnode_on_parent[rw], tg); | |
386 | } | |
387 | ||
388 | RB_CLEAR_NODE(&tg->rb_node); | |
9f626e37 SL |
389 | tg->bps[READ][LIMIT_MAX] = U64_MAX; |
390 | tg->bps[WRITE][LIMIT_MAX] = U64_MAX; | |
391 | tg->iops[READ][LIMIT_MAX] = UINT_MAX; | |
392 | tg->iops[WRITE][LIMIT_MAX] = UINT_MAX; | |
cd5ab1b0 SL |
393 | tg->bps_conf[READ][LIMIT_MAX] = U64_MAX; |
394 | tg->bps_conf[WRITE][LIMIT_MAX] = U64_MAX; | |
395 | tg->iops_conf[READ][LIMIT_MAX] = UINT_MAX; | |
396 | tg->iops_conf[WRITE][LIMIT_MAX] = UINT_MAX; | |
397 | /* LIMIT_LOW will have default value 0 */ | |
b2ce2643 | 398 | |
4fb72036 | 399 | return &tg->pd; |
001bea73 TH |
400 | } |
401 | ||
a9520cd6 | 402 | static void throtl_pd_init(struct blkg_policy_data *pd) |
a29a171e | 403 | { |
a9520cd6 TH |
404 | struct throtl_grp *tg = pd_to_tg(pd); |
405 | struct blkcg_gq *blkg = tg_to_blkg(tg); | |
77216b04 | 406 | struct throtl_data *td = blkg->q->td; |
b2ce2643 | 407 | struct throtl_service_queue *sq = &tg->service_queue; |
cd1604fa | 408 | |
9138125b | 409 | /* |
aa6ec29b | 410 | * If on the default hierarchy, we switch to properly hierarchical |
9138125b TH |
411 | * behavior where limits on a given throtl_grp are applied to the |
412 | * whole subtree rather than just the group itself. e.g. If 16M | |
413 | * read_bps limit is set on the root group, the whole system can't | |
414 | * exceed 16M for the device. | |
415 | * | |
aa6ec29b | 416 | * If not on the default hierarchy, the broken flat hierarchy |
9138125b TH |
417 | * behavior is retained where all throtl_grps are treated as if |
418 | * they're all separate root groups right below throtl_data. | |
419 | * Limits of a group don't interact with limits of other groups | |
420 | * regardless of the position of the group in the hierarchy. | |
421 | */ | |
b2ce2643 | 422 | sq->parent_sq = &td->service_queue; |
9e10a130 | 423 | if (cgroup_subsys_on_dfl(io_cgrp_subsys) && blkg->parent) |
b2ce2643 | 424 | sq->parent_sq = &blkg_to_tg(blkg->parent)->service_queue; |
77216b04 | 425 | tg->td = td; |
8a3d2615 TH |
426 | } |
427 | ||
693e751e TH |
428 | /* |
429 | * Set has_rules[] if @tg or any of its parents have limits configured. | |
430 | * This doesn't require walking up to the top of the hierarchy as the | |
431 | * parent's has_rules[] is guaranteed to be correct. | |
432 | */ | |
433 | static void tg_update_has_rules(struct throtl_grp *tg) | |
434 | { | |
435 | struct throtl_grp *parent_tg = sq_to_tg(tg->service_queue.parent_sq); | |
9f626e37 | 436 | struct throtl_data *td = tg->td; |
693e751e TH |
437 | int rw; |
438 | ||
439 | for (rw = READ; rw <= WRITE; rw++) | |
440 | tg->has_rules[rw] = (parent_tg && parent_tg->has_rules[rw]) || | |
9f626e37 SL |
441 | (td->limit_valid[td->limit_index] && |
442 | (tg_bps_limit(tg, rw) != U64_MAX || | |
443 | tg_iops_limit(tg, rw) != UINT_MAX)); | |
693e751e TH |
444 | } |
445 | ||
a9520cd6 | 446 | static void throtl_pd_online(struct blkg_policy_data *pd) |
693e751e TH |
447 | { |
448 | /* | |
449 | * We don't want new groups to escape the limits of its ancestors. | |
450 | * Update has_rules[] after a new group is brought online. | |
451 | */ | |
a9520cd6 | 452 | tg_update_has_rules(pd_to_tg(pd)); |
693e751e TH |
453 | } |
454 | ||
cd5ab1b0 SL |
455 | static void blk_throtl_update_limit_valid(struct throtl_data *td) |
456 | { | |
457 | struct cgroup_subsys_state *pos_css; | |
458 | struct blkcg_gq *blkg; | |
459 | bool low_valid = false; | |
460 | ||
461 | rcu_read_lock(); | |
462 | blkg_for_each_descendant_post(blkg, pos_css, td->queue->root_blkg) { | |
463 | struct throtl_grp *tg = blkg_to_tg(blkg); | |
464 | ||
465 | if (tg->bps[READ][LIMIT_LOW] || tg->bps[WRITE][LIMIT_LOW] || | |
466 | tg->iops[READ][LIMIT_LOW] || tg->iops[WRITE][LIMIT_LOW]) | |
467 | low_valid = true; | |
468 | } | |
469 | rcu_read_unlock(); | |
470 | ||
471 | td->limit_valid[LIMIT_LOW] = low_valid; | |
472 | } | |
473 | ||
c79892c5 | 474 | static void throtl_upgrade_state(struct throtl_data *td); |
cd5ab1b0 SL |
475 | static void throtl_pd_offline(struct blkg_policy_data *pd) |
476 | { | |
477 | struct throtl_grp *tg = pd_to_tg(pd); | |
478 | ||
479 | tg->bps[READ][LIMIT_LOW] = 0; | |
480 | tg->bps[WRITE][LIMIT_LOW] = 0; | |
481 | tg->iops[READ][LIMIT_LOW] = 0; | |
482 | tg->iops[WRITE][LIMIT_LOW] = 0; | |
483 | ||
484 | blk_throtl_update_limit_valid(tg->td); | |
485 | ||
c79892c5 SL |
486 | if (!tg->td->limit_valid[tg->td->limit_index]) |
487 | throtl_upgrade_state(tg->td); | |
cd5ab1b0 SL |
488 | } |
489 | ||
001bea73 TH |
490 | static void throtl_pd_free(struct blkg_policy_data *pd) |
491 | { | |
4fb72036 TH |
492 | struct throtl_grp *tg = pd_to_tg(pd); |
493 | ||
b2ce2643 | 494 | del_timer_sync(&tg->service_queue.pending_timer); |
4fb72036 | 495 | kfree(tg); |
001bea73 TH |
496 | } |
497 | ||
0049af73 TH |
498 | static struct throtl_grp * |
499 | throtl_rb_first(struct throtl_service_queue *parent_sq) | |
e43473b7 VG |
500 | { |
501 | /* Service tree is empty */ | |
0049af73 | 502 | if (!parent_sq->nr_pending) |
e43473b7 VG |
503 | return NULL; |
504 | ||
0049af73 TH |
505 | if (!parent_sq->first_pending) |
506 | parent_sq->first_pending = rb_first(&parent_sq->pending_tree); | |
e43473b7 | 507 | |
0049af73 TH |
508 | if (parent_sq->first_pending) |
509 | return rb_entry_tg(parent_sq->first_pending); | |
e43473b7 VG |
510 | |
511 | return NULL; | |
512 | } | |
513 | ||
514 | static void rb_erase_init(struct rb_node *n, struct rb_root *root) | |
515 | { | |
516 | rb_erase(n, root); | |
517 | RB_CLEAR_NODE(n); | |
518 | } | |
519 | ||
0049af73 TH |
520 | static void throtl_rb_erase(struct rb_node *n, |
521 | struct throtl_service_queue *parent_sq) | |
e43473b7 | 522 | { |
0049af73 TH |
523 | if (parent_sq->first_pending == n) |
524 | parent_sq->first_pending = NULL; | |
525 | rb_erase_init(n, &parent_sq->pending_tree); | |
526 | --parent_sq->nr_pending; | |
e43473b7 VG |
527 | } |
528 | ||
0049af73 | 529 | static void update_min_dispatch_time(struct throtl_service_queue *parent_sq) |
e43473b7 VG |
530 | { |
531 | struct throtl_grp *tg; | |
532 | ||
0049af73 | 533 | tg = throtl_rb_first(parent_sq); |
e43473b7 VG |
534 | if (!tg) |
535 | return; | |
536 | ||
0049af73 | 537 | parent_sq->first_pending_disptime = tg->disptime; |
e43473b7 VG |
538 | } |
539 | ||
77216b04 | 540 | static void tg_service_queue_add(struct throtl_grp *tg) |
e43473b7 | 541 | { |
77216b04 | 542 | struct throtl_service_queue *parent_sq = tg->service_queue.parent_sq; |
0049af73 | 543 | struct rb_node **node = &parent_sq->pending_tree.rb_node; |
e43473b7 VG |
544 | struct rb_node *parent = NULL; |
545 | struct throtl_grp *__tg; | |
546 | unsigned long key = tg->disptime; | |
547 | int left = 1; | |
548 | ||
549 | while (*node != NULL) { | |
550 | parent = *node; | |
551 | __tg = rb_entry_tg(parent); | |
552 | ||
553 | if (time_before(key, __tg->disptime)) | |
554 | node = &parent->rb_left; | |
555 | else { | |
556 | node = &parent->rb_right; | |
557 | left = 0; | |
558 | } | |
559 | } | |
560 | ||
561 | if (left) | |
0049af73 | 562 | parent_sq->first_pending = &tg->rb_node; |
e43473b7 VG |
563 | |
564 | rb_link_node(&tg->rb_node, parent, node); | |
0049af73 | 565 | rb_insert_color(&tg->rb_node, &parent_sq->pending_tree); |
e43473b7 VG |
566 | } |
567 | ||
77216b04 | 568 | static void __throtl_enqueue_tg(struct throtl_grp *tg) |
e43473b7 | 569 | { |
77216b04 | 570 | tg_service_queue_add(tg); |
5b2c16aa | 571 | tg->flags |= THROTL_TG_PENDING; |
77216b04 | 572 | tg->service_queue.parent_sq->nr_pending++; |
e43473b7 VG |
573 | } |
574 | ||
77216b04 | 575 | static void throtl_enqueue_tg(struct throtl_grp *tg) |
e43473b7 | 576 | { |
5b2c16aa | 577 | if (!(tg->flags & THROTL_TG_PENDING)) |
77216b04 | 578 | __throtl_enqueue_tg(tg); |
e43473b7 VG |
579 | } |
580 | ||
77216b04 | 581 | static void __throtl_dequeue_tg(struct throtl_grp *tg) |
e43473b7 | 582 | { |
77216b04 | 583 | throtl_rb_erase(&tg->rb_node, tg->service_queue.parent_sq); |
5b2c16aa | 584 | tg->flags &= ~THROTL_TG_PENDING; |
e43473b7 VG |
585 | } |
586 | ||
77216b04 | 587 | static void throtl_dequeue_tg(struct throtl_grp *tg) |
e43473b7 | 588 | { |
5b2c16aa | 589 | if (tg->flags & THROTL_TG_PENDING) |
77216b04 | 590 | __throtl_dequeue_tg(tg); |
e43473b7 VG |
591 | } |
592 | ||
a9131a27 | 593 | /* Call with queue lock held */ |
69df0ab0 TH |
594 | static void throtl_schedule_pending_timer(struct throtl_service_queue *sq, |
595 | unsigned long expires) | |
a9131a27 | 596 | { |
297e3d85 | 597 | unsigned long max_expire = jiffies + 8 * sq_to_tg(sq)->td->throtl_slice; |
06cceedc SL |
598 | |
599 | /* | |
600 | * Since we are adjusting the throttle limit dynamically, the sleep | |
601 | * time calculated according to previous limit might be invalid. It's | |
602 | * possible the cgroup sleep time is very long and no other cgroups | |
603 | * have IO running so notify the limit changes. Make sure the cgroup | |
604 | * doesn't sleep too long to avoid the missed notification. | |
605 | */ | |
606 | if (time_after(expires, max_expire)) | |
607 | expires = max_expire; | |
69df0ab0 TH |
608 | mod_timer(&sq->pending_timer, expires); |
609 | throtl_log(sq, "schedule timer. delay=%lu jiffies=%lu", | |
610 | expires - jiffies, jiffies); | |
a9131a27 TH |
611 | } |
612 | ||
7f52f98c TH |
613 | /** |
614 | * throtl_schedule_next_dispatch - schedule the next dispatch cycle | |
615 | * @sq: the service_queue to schedule dispatch for | |
616 | * @force: force scheduling | |
617 | * | |
618 | * Arm @sq->pending_timer so that the next dispatch cycle starts on the | |
619 | * dispatch time of the first pending child. Returns %true if either timer | |
620 | * is armed or there's no pending child left. %false if the current | |
621 | * dispatch window is still open and the caller should continue | |
622 | * dispatching. | |
623 | * | |
624 | * If @force is %true, the dispatch timer is always scheduled and this | |
625 | * function is guaranteed to return %true. This is to be used when the | |
626 | * caller can't dispatch itself and needs to invoke pending_timer | |
627 | * unconditionally. Note that forced scheduling is likely to induce short | |
628 | * delay before dispatch starts even if @sq->first_pending_disptime is not | |
629 | * in the future and thus shouldn't be used in hot paths. | |
630 | */ | |
631 | static bool throtl_schedule_next_dispatch(struct throtl_service_queue *sq, | |
632 | bool force) | |
e43473b7 | 633 | { |
6a525600 | 634 | /* any pending children left? */ |
c9e0332e | 635 | if (!sq->nr_pending) |
7f52f98c | 636 | return true; |
e43473b7 | 637 | |
c9e0332e | 638 | update_min_dispatch_time(sq); |
e43473b7 | 639 | |
69df0ab0 | 640 | /* is the next dispatch time in the future? */ |
7f52f98c | 641 | if (force || time_after(sq->first_pending_disptime, jiffies)) { |
69df0ab0 | 642 | throtl_schedule_pending_timer(sq, sq->first_pending_disptime); |
7f52f98c | 643 | return true; |
69df0ab0 TH |
644 | } |
645 | ||
7f52f98c TH |
646 | /* tell the caller to continue dispatching */ |
647 | return false; | |
e43473b7 VG |
648 | } |
649 | ||
32ee5bc4 VG |
650 | static inline void throtl_start_new_slice_with_credit(struct throtl_grp *tg, |
651 | bool rw, unsigned long start) | |
652 | { | |
653 | tg->bytes_disp[rw] = 0; | |
654 | tg->io_disp[rw] = 0; | |
655 | ||
656 | /* | |
657 | * Previous slice has expired. We must have trimmed it after last | |
658 | * bio dispatch. That means since start of last slice, we never used | |
659 | * that bandwidth. Do try to make use of that bandwidth while giving | |
660 | * credit. | |
661 | */ | |
662 | if (time_after_eq(start, tg->slice_start[rw])) | |
663 | tg->slice_start[rw] = start; | |
664 | ||
297e3d85 | 665 | tg->slice_end[rw] = jiffies + tg->td->throtl_slice; |
32ee5bc4 VG |
666 | throtl_log(&tg->service_queue, |
667 | "[%c] new slice with credit start=%lu end=%lu jiffies=%lu", | |
668 | rw == READ ? 'R' : 'W', tg->slice_start[rw], | |
669 | tg->slice_end[rw], jiffies); | |
670 | } | |
671 | ||
0f3457f6 | 672 | static inline void throtl_start_new_slice(struct throtl_grp *tg, bool rw) |
e43473b7 VG |
673 | { |
674 | tg->bytes_disp[rw] = 0; | |
8e89d13f | 675 | tg->io_disp[rw] = 0; |
e43473b7 | 676 | tg->slice_start[rw] = jiffies; |
297e3d85 | 677 | tg->slice_end[rw] = jiffies + tg->td->throtl_slice; |
fda6f272 TH |
678 | throtl_log(&tg->service_queue, |
679 | "[%c] new slice start=%lu end=%lu jiffies=%lu", | |
680 | rw == READ ? 'R' : 'W', tg->slice_start[rw], | |
681 | tg->slice_end[rw], jiffies); | |
e43473b7 VG |
682 | } |
683 | ||
0f3457f6 TH |
684 | static inline void throtl_set_slice_end(struct throtl_grp *tg, bool rw, |
685 | unsigned long jiffy_end) | |
d1ae8ffd | 686 | { |
297e3d85 | 687 | tg->slice_end[rw] = roundup(jiffy_end, tg->td->throtl_slice); |
d1ae8ffd VG |
688 | } |
689 | ||
0f3457f6 TH |
690 | static inline void throtl_extend_slice(struct throtl_grp *tg, bool rw, |
691 | unsigned long jiffy_end) | |
e43473b7 | 692 | { |
297e3d85 | 693 | tg->slice_end[rw] = roundup(jiffy_end, tg->td->throtl_slice); |
fda6f272 TH |
694 | throtl_log(&tg->service_queue, |
695 | "[%c] extend slice start=%lu end=%lu jiffies=%lu", | |
696 | rw == READ ? 'R' : 'W', tg->slice_start[rw], | |
697 | tg->slice_end[rw], jiffies); | |
e43473b7 VG |
698 | } |
699 | ||
700 | /* Determine if previously allocated or extended slice is complete or not */ | |
0f3457f6 | 701 | static bool throtl_slice_used(struct throtl_grp *tg, bool rw) |
e43473b7 VG |
702 | { |
703 | if (time_in_range(jiffies, tg->slice_start[rw], tg->slice_end[rw])) | |
5cf8c227 | 704 | return false; |
e43473b7 VG |
705 | |
706 | return 1; | |
707 | } | |
708 | ||
709 | /* Trim the used slices and adjust slice start accordingly */ | |
0f3457f6 | 710 | static inline void throtl_trim_slice(struct throtl_grp *tg, bool rw) |
e43473b7 | 711 | { |
3aad5d3e VG |
712 | unsigned long nr_slices, time_elapsed, io_trim; |
713 | u64 bytes_trim, tmp; | |
e43473b7 VG |
714 | |
715 | BUG_ON(time_before(tg->slice_end[rw], tg->slice_start[rw])); | |
716 | ||
717 | /* | |
718 | * If bps are unlimited (-1), then time slice don't get | |
719 | * renewed. Don't try to trim the slice if slice is used. A new | |
720 | * slice will start when appropriate. | |
721 | */ | |
0f3457f6 | 722 | if (throtl_slice_used(tg, rw)) |
e43473b7 VG |
723 | return; |
724 | ||
d1ae8ffd VG |
725 | /* |
726 | * A bio has been dispatched. Also adjust slice_end. It might happen | |
727 | * that initially cgroup limit was very low resulting in high | |
728 | * slice_end, but later limit was bumped up and bio was dispached | |
729 | * sooner, then we need to reduce slice_end. A high bogus slice_end | |
730 | * is bad because it does not allow new slice to start. | |
731 | */ | |
732 | ||
297e3d85 | 733 | throtl_set_slice_end(tg, rw, jiffies + tg->td->throtl_slice); |
d1ae8ffd | 734 | |
e43473b7 VG |
735 | time_elapsed = jiffies - tg->slice_start[rw]; |
736 | ||
297e3d85 | 737 | nr_slices = time_elapsed / tg->td->throtl_slice; |
e43473b7 VG |
738 | |
739 | if (!nr_slices) | |
740 | return; | |
297e3d85 | 741 | tmp = tg_bps_limit(tg, rw) * tg->td->throtl_slice * nr_slices; |
3aad5d3e VG |
742 | do_div(tmp, HZ); |
743 | bytes_trim = tmp; | |
e43473b7 | 744 | |
297e3d85 SL |
745 | io_trim = (tg_iops_limit(tg, rw) * tg->td->throtl_slice * nr_slices) / |
746 | HZ; | |
e43473b7 | 747 | |
8e89d13f | 748 | if (!bytes_trim && !io_trim) |
e43473b7 VG |
749 | return; |
750 | ||
751 | if (tg->bytes_disp[rw] >= bytes_trim) | |
752 | tg->bytes_disp[rw] -= bytes_trim; | |
753 | else | |
754 | tg->bytes_disp[rw] = 0; | |
755 | ||
8e89d13f VG |
756 | if (tg->io_disp[rw] >= io_trim) |
757 | tg->io_disp[rw] -= io_trim; | |
758 | else | |
759 | tg->io_disp[rw] = 0; | |
760 | ||
297e3d85 | 761 | tg->slice_start[rw] += nr_slices * tg->td->throtl_slice; |
e43473b7 | 762 | |
fda6f272 TH |
763 | throtl_log(&tg->service_queue, |
764 | "[%c] trim slice nr=%lu bytes=%llu io=%lu start=%lu end=%lu jiffies=%lu", | |
765 | rw == READ ? 'R' : 'W', nr_slices, bytes_trim, io_trim, | |
766 | tg->slice_start[rw], tg->slice_end[rw], jiffies); | |
e43473b7 VG |
767 | } |
768 | ||
0f3457f6 TH |
769 | static bool tg_with_in_iops_limit(struct throtl_grp *tg, struct bio *bio, |
770 | unsigned long *wait) | |
e43473b7 VG |
771 | { |
772 | bool rw = bio_data_dir(bio); | |
8e89d13f | 773 | unsigned int io_allowed; |
e43473b7 | 774 | unsigned long jiffy_elapsed, jiffy_wait, jiffy_elapsed_rnd; |
c49c06e4 | 775 | u64 tmp; |
e43473b7 | 776 | |
8e89d13f | 777 | jiffy_elapsed = jiffy_elapsed_rnd = jiffies - tg->slice_start[rw]; |
e43473b7 | 778 | |
8e89d13f VG |
779 | /* Slice has just started. Consider one slice interval */ |
780 | if (!jiffy_elapsed) | |
297e3d85 | 781 | jiffy_elapsed_rnd = tg->td->throtl_slice; |
8e89d13f | 782 | |
297e3d85 | 783 | jiffy_elapsed_rnd = roundup(jiffy_elapsed_rnd, tg->td->throtl_slice); |
8e89d13f | 784 | |
c49c06e4 VG |
785 | /* |
786 | * jiffy_elapsed_rnd should not be a big value as minimum iops can be | |
787 | * 1 then at max jiffy elapsed should be equivalent of 1 second as we | |
788 | * will allow dispatch after 1 second and after that slice should | |
789 | * have been trimmed. | |
790 | */ | |
791 | ||
9f626e37 | 792 | tmp = (u64)tg_iops_limit(tg, rw) * jiffy_elapsed_rnd; |
c49c06e4 VG |
793 | do_div(tmp, HZ); |
794 | ||
795 | if (tmp > UINT_MAX) | |
796 | io_allowed = UINT_MAX; | |
797 | else | |
798 | io_allowed = tmp; | |
8e89d13f VG |
799 | |
800 | if (tg->io_disp[rw] + 1 <= io_allowed) { | |
e43473b7 VG |
801 | if (wait) |
802 | *wait = 0; | |
5cf8c227 | 803 | return true; |
e43473b7 VG |
804 | } |
805 | ||
8e89d13f | 806 | /* Calc approx time to dispatch */ |
9f626e37 | 807 | jiffy_wait = ((tg->io_disp[rw] + 1) * HZ) / tg_iops_limit(tg, rw) + 1; |
8e89d13f VG |
808 | |
809 | if (jiffy_wait > jiffy_elapsed) | |
810 | jiffy_wait = jiffy_wait - jiffy_elapsed; | |
811 | else | |
812 | jiffy_wait = 1; | |
813 | ||
814 | if (wait) | |
815 | *wait = jiffy_wait; | |
816 | return 0; | |
817 | } | |
818 | ||
0f3457f6 TH |
819 | static bool tg_with_in_bps_limit(struct throtl_grp *tg, struct bio *bio, |
820 | unsigned long *wait) | |
8e89d13f VG |
821 | { |
822 | bool rw = bio_data_dir(bio); | |
3aad5d3e | 823 | u64 bytes_allowed, extra_bytes, tmp; |
8e89d13f | 824 | unsigned long jiffy_elapsed, jiffy_wait, jiffy_elapsed_rnd; |
e43473b7 VG |
825 | |
826 | jiffy_elapsed = jiffy_elapsed_rnd = jiffies - tg->slice_start[rw]; | |
827 | ||
828 | /* Slice has just started. Consider one slice interval */ | |
829 | if (!jiffy_elapsed) | |
297e3d85 | 830 | jiffy_elapsed_rnd = tg->td->throtl_slice; |
e43473b7 | 831 | |
297e3d85 | 832 | jiffy_elapsed_rnd = roundup(jiffy_elapsed_rnd, tg->td->throtl_slice); |
e43473b7 | 833 | |
9f626e37 | 834 | tmp = tg_bps_limit(tg, rw) * jiffy_elapsed_rnd; |
5e901a2b | 835 | do_div(tmp, HZ); |
3aad5d3e | 836 | bytes_allowed = tmp; |
e43473b7 | 837 | |
4f024f37 | 838 | if (tg->bytes_disp[rw] + bio->bi_iter.bi_size <= bytes_allowed) { |
e43473b7 VG |
839 | if (wait) |
840 | *wait = 0; | |
5cf8c227 | 841 | return true; |
e43473b7 VG |
842 | } |
843 | ||
844 | /* Calc approx time to dispatch */ | |
4f024f37 | 845 | extra_bytes = tg->bytes_disp[rw] + bio->bi_iter.bi_size - bytes_allowed; |
9f626e37 | 846 | jiffy_wait = div64_u64(extra_bytes * HZ, tg_bps_limit(tg, rw)); |
e43473b7 VG |
847 | |
848 | if (!jiffy_wait) | |
849 | jiffy_wait = 1; | |
850 | ||
851 | /* | |
852 | * This wait time is without taking into consideration the rounding | |
853 | * up we did. Add that time also. | |
854 | */ | |
855 | jiffy_wait = jiffy_wait + (jiffy_elapsed_rnd - jiffy_elapsed); | |
e43473b7 VG |
856 | if (wait) |
857 | *wait = jiffy_wait; | |
8e89d13f VG |
858 | return 0; |
859 | } | |
860 | ||
861 | /* | |
862 | * Returns whether one can dispatch a bio or not. Also returns approx number | |
863 | * of jiffies to wait before this bio is with-in IO rate and can be dispatched | |
864 | */ | |
0f3457f6 TH |
865 | static bool tg_may_dispatch(struct throtl_grp *tg, struct bio *bio, |
866 | unsigned long *wait) | |
8e89d13f VG |
867 | { |
868 | bool rw = bio_data_dir(bio); | |
869 | unsigned long bps_wait = 0, iops_wait = 0, max_wait = 0; | |
870 | ||
871 | /* | |
872 | * Currently whole state machine of group depends on first bio | |
873 | * queued in the group bio list. So one should not be calling | |
874 | * this function with a different bio if there are other bios | |
875 | * queued. | |
876 | */ | |
73f0d49a | 877 | BUG_ON(tg->service_queue.nr_queued[rw] && |
c5cc2070 | 878 | bio != throtl_peek_queued(&tg->service_queue.queued[rw])); |
e43473b7 | 879 | |
8e89d13f | 880 | /* If tg->bps = -1, then BW is unlimited */ |
9f626e37 SL |
881 | if (tg_bps_limit(tg, rw) == U64_MAX && |
882 | tg_iops_limit(tg, rw) == UINT_MAX) { | |
8e89d13f VG |
883 | if (wait) |
884 | *wait = 0; | |
5cf8c227 | 885 | return true; |
8e89d13f VG |
886 | } |
887 | ||
888 | /* | |
889 | * If previous slice expired, start a new one otherwise renew/extend | |
890 | * existing slice to make sure it is at least throtl_slice interval | |
164c80ed VG |
891 | * long since now. New slice is started only for empty throttle group. |
892 | * If there is queued bio, that means there should be an active | |
893 | * slice and it should be extended instead. | |
8e89d13f | 894 | */ |
164c80ed | 895 | if (throtl_slice_used(tg, rw) && !(tg->service_queue.nr_queued[rw])) |
0f3457f6 | 896 | throtl_start_new_slice(tg, rw); |
8e89d13f | 897 | else { |
297e3d85 SL |
898 | if (time_before(tg->slice_end[rw], |
899 | jiffies + tg->td->throtl_slice)) | |
900 | throtl_extend_slice(tg, rw, | |
901 | jiffies + tg->td->throtl_slice); | |
8e89d13f VG |
902 | } |
903 | ||
0f3457f6 TH |
904 | if (tg_with_in_bps_limit(tg, bio, &bps_wait) && |
905 | tg_with_in_iops_limit(tg, bio, &iops_wait)) { | |
8e89d13f VG |
906 | if (wait) |
907 | *wait = 0; | |
908 | return 1; | |
909 | } | |
910 | ||
911 | max_wait = max(bps_wait, iops_wait); | |
912 | ||
913 | if (wait) | |
914 | *wait = max_wait; | |
915 | ||
916 | if (time_before(tg->slice_end[rw], jiffies + max_wait)) | |
0f3457f6 | 917 | throtl_extend_slice(tg, rw, jiffies + max_wait); |
e43473b7 VG |
918 | |
919 | return 0; | |
920 | } | |
921 | ||
922 | static void throtl_charge_bio(struct throtl_grp *tg, struct bio *bio) | |
923 | { | |
924 | bool rw = bio_data_dir(bio); | |
e43473b7 VG |
925 | |
926 | /* Charge the bio to the group */ | |
4f024f37 | 927 | tg->bytes_disp[rw] += bio->bi_iter.bi_size; |
8e89d13f | 928 | tg->io_disp[rw]++; |
3f0abd80 SL |
929 | tg->last_bytes_disp[rw] += bio->bi_iter.bi_size; |
930 | tg->last_io_disp[rw]++; | |
e43473b7 | 931 | |
2a0f61e6 | 932 | /* |
8d2bbd4c | 933 | * BIO_THROTTLED is used to prevent the same bio to be throttled |
2a0f61e6 TH |
934 | * more than once as a throttled bio will go through blk-throtl the |
935 | * second time when it eventually gets issued. Set it when a bio | |
936 | * is being charged to a tg. | |
2a0f61e6 | 937 | */ |
8d2bbd4c CH |
938 | if (!bio_flagged(bio, BIO_THROTTLED)) |
939 | bio_set_flag(bio, BIO_THROTTLED); | |
e43473b7 VG |
940 | } |
941 | ||
c5cc2070 TH |
942 | /** |
943 | * throtl_add_bio_tg - add a bio to the specified throtl_grp | |
944 | * @bio: bio to add | |
945 | * @qn: qnode to use | |
946 | * @tg: the target throtl_grp | |
947 | * | |
948 | * Add @bio to @tg's service_queue using @qn. If @qn is not specified, | |
949 | * tg->qnode_on_self[] is used. | |
950 | */ | |
951 | static void throtl_add_bio_tg(struct bio *bio, struct throtl_qnode *qn, | |
952 | struct throtl_grp *tg) | |
e43473b7 | 953 | { |
73f0d49a | 954 | struct throtl_service_queue *sq = &tg->service_queue; |
e43473b7 VG |
955 | bool rw = bio_data_dir(bio); |
956 | ||
c5cc2070 TH |
957 | if (!qn) |
958 | qn = &tg->qnode_on_self[rw]; | |
959 | ||
0e9f4164 TH |
960 | /* |
961 | * If @tg doesn't currently have any bios queued in the same | |
962 | * direction, queueing @bio can change when @tg should be | |
963 | * dispatched. Mark that @tg was empty. This is automatically | |
964 | * cleaered on the next tg_update_disptime(). | |
965 | */ | |
966 | if (!sq->nr_queued[rw]) | |
967 | tg->flags |= THROTL_TG_WAS_EMPTY; | |
968 | ||
c5cc2070 TH |
969 | throtl_qnode_add_bio(bio, qn, &sq->queued[rw]); |
970 | ||
73f0d49a | 971 | sq->nr_queued[rw]++; |
77216b04 | 972 | throtl_enqueue_tg(tg); |
e43473b7 VG |
973 | } |
974 | ||
77216b04 | 975 | static void tg_update_disptime(struct throtl_grp *tg) |
e43473b7 | 976 | { |
73f0d49a | 977 | struct throtl_service_queue *sq = &tg->service_queue; |
e43473b7 VG |
978 | unsigned long read_wait = -1, write_wait = -1, min_wait = -1, disptime; |
979 | struct bio *bio; | |
980 | ||
d609af3a ME |
981 | bio = throtl_peek_queued(&sq->queued[READ]); |
982 | if (bio) | |
0f3457f6 | 983 | tg_may_dispatch(tg, bio, &read_wait); |
e43473b7 | 984 | |
d609af3a ME |
985 | bio = throtl_peek_queued(&sq->queued[WRITE]); |
986 | if (bio) | |
0f3457f6 | 987 | tg_may_dispatch(tg, bio, &write_wait); |
e43473b7 VG |
988 | |
989 | min_wait = min(read_wait, write_wait); | |
990 | disptime = jiffies + min_wait; | |
991 | ||
e43473b7 | 992 | /* Update dispatch time */ |
77216b04 | 993 | throtl_dequeue_tg(tg); |
e43473b7 | 994 | tg->disptime = disptime; |
77216b04 | 995 | throtl_enqueue_tg(tg); |
0e9f4164 TH |
996 | |
997 | /* see throtl_add_bio_tg() */ | |
998 | tg->flags &= ~THROTL_TG_WAS_EMPTY; | |
e43473b7 VG |
999 | } |
1000 | ||
32ee5bc4 VG |
1001 | static void start_parent_slice_with_credit(struct throtl_grp *child_tg, |
1002 | struct throtl_grp *parent_tg, bool rw) | |
1003 | { | |
1004 | if (throtl_slice_used(parent_tg, rw)) { | |
1005 | throtl_start_new_slice_with_credit(parent_tg, rw, | |
1006 | child_tg->slice_start[rw]); | |
1007 | } | |
1008 | ||
1009 | } | |
1010 | ||
77216b04 | 1011 | static void tg_dispatch_one_bio(struct throtl_grp *tg, bool rw) |
e43473b7 | 1012 | { |
73f0d49a | 1013 | struct throtl_service_queue *sq = &tg->service_queue; |
6bc9c2b4 TH |
1014 | struct throtl_service_queue *parent_sq = sq->parent_sq; |
1015 | struct throtl_grp *parent_tg = sq_to_tg(parent_sq); | |
c5cc2070 | 1016 | struct throtl_grp *tg_to_put = NULL; |
e43473b7 VG |
1017 | struct bio *bio; |
1018 | ||
c5cc2070 TH |
1019 | /* |
1020 | * @bio is being transferred from @tg to @parent_sq. Popping a bio | |
1021 | * from @tg may put its reference and @parent_sq might end up | |
1022 | * getting released prematurely. Remember the tg to put and put it | |
1023 | * after @bio is transferred to @parent_sq. | |
1024 | */ | |
1025 | bio = throtl_pop_queued(&sq->queued[rw], &tg_to_put); | |
73f0d49a | 1026 | sq->nr_queued[rw]--; |
e43473b7 VG |
1027 | |
1028 | throtl_charge_bio(tg, bio); | |
6bc9c2b4 TH |
1029 | |
1030 | /* | |
1031 | * If our parent is another tg, we just need to transfer @bio to | |
1032 | * the parent using throtl_add_bio_tg(). If our parent is | |
1033 | * @td->service_queue, @bio is ready to be issued. Put it on its | |
1034 | * bio_lists[] and decrease total number queued. The caller is | |
1035 | * responsible for issuing these bios. | |
1036 | */ | |
1037 | if (parent_tg) { | |
c5cc2070 | 1038 | throtl_add_bio_tg(bio, &tg->qnode_on_parent[rw], parent_tg); |
32ee5bc4 | 1039 | start_parent_slice_with_credit(tg, parent_tg, rw); |
6bc9c2b4 | 1040 | } else { |
c5cc2070 TH |
1041 | throtl_qnode_add_bio(bio, &tg->qnode_on_parent[rw], |
1042 | &parent_sq->queued[rw]); | |
6bc9c2b4 TH |
1043 | BUG_ON(tg->td->nr_queued[rw] <= 0); |
1044 | tg->td->nr_queued[rw]--; | |
1045 | } | |
e43473b7 | 1046 | |
0f3457f6 | 1047 | throtl_trim_slice(tg, rw); |
6bc9c2b4 | 1048 | |
c5cc2070 TH |
1049 | if (tg_to_put) |
1050 | blkg_put(tg_to_blkg(tg_to_put)); | |
e43473b7 VG |
1051 | } |
1052 | ||
77216b04 | 1053 | static int throtl_dispatch_tg(struct throtl_grp *tg) |
e43473b7 | 1054 | { |
73f0d49a | 1055 | struct throtl_service_queue *sq = &tg->service_queue; |
e43473b7 VG |
1056 | unsigned int nr_reads = 0, nr_writes = 0; |
1057 | unsigned int max_nr_reads = throtl_grp_quantum*3/4; | |
c2f6805d | 1058 | unsigned int max_nr_writes = throtl_grp_quantum - max_nr_reads; |
e43473b7 VG |
1059 | struct bio *bio; |
1060 | ||
1061 | /* Try to dispatch 75% READS and 25% WRITES */ | |
1062 | ||
c5cc2070 | 1063 | while ((bio = throtl_peek_queued(&sq->queued[READ])) && |
0f3457f6 | 1064 | tg_may_dispatch(tg, bio, NULL)) { |
e43473b7 | 1065 | |
77216b04 | 1066 | tg_dispatch_one_bio(tg, bio_data_dir(bio)); |
e43473b7 VG |
1067 | nr_reads++; |
1068 | ||
1069 | if (nr_reads >= max_nr_reads) | |
1070 | break; | |
1071 | } | |
1072 | ||
c5cc2070 | 1073 | while ((bio = throtl_peek_queued(&sq->queued[WRITE])) && |
0f3457f6 | 1074 | tg_may_dispatch(tg, bio, NULL)) { |
e43473b7 | 1075 | |
77216b04 | 1076 | tg_dispatch_one_bio(tg, bio_data_dir(bio)); |
e43473b7 VG |
1077 | nr_writes++; |
1078 | ||
1079 | if (nr_writes >= max_nr_writes) | |
1080 | break; | |
1081 | } | |
1082 | ||
1083 | return nr_reads + nr_writes; | |
1084 | } | |
1085 | ||
651930bc | 1086 | static int throtl_select_dispatch(struct throtl_service_queue *parent_sq) |
e43473b7 VG |
1087 | { |
1088 | unsigned int nr_disp = 0; | |
e43473b7 VG |
1089 | |
1090 | while (1) { | |
73f0d49a TH |
1091 | struct throtl_grp *tg = throtl_rb_first(parent_sq); |
1092 | struct throtl_service_queue *sq = &tg->service_queue; | |
e43473b7 VG |
1093 | |
1094 | if (!tg) | |
1095 | break; | |
1096 | ||
1097 | if (time_before(jiffies, tg->disptime)) | |
1098 | break; | |
1099 | ||
77216b04 | 1100 | throtl_dequeue_tg(tg); |
e43473b7 | 1101 | |
77216b04 | 1102 | nr_disp += throtl_dispatch_tg(tg); |
e43473b7 | 1103 | |
73f0d49a | 1104 | if (sq->nr_queued[0] || sq->nr_queued[1]) |
77216b04 | 1105 | tg_update_disptime(tg); |
e43473b7 VG |
1106 | |
1107 | if (nr_disp >= throtl_quantum) | |
1108 | break; | |
1109 | } | |
1110 | ||
1111 | return nr_disp; | |
1112 | } | |
1113 | ||
c79892c5 SL |
1114 | static bool throtl_can_upgrade(struct throtl_data *td, |
1115 | struct throtl_grp *this_tg); | |
6e1a5704 TH |
1116 | /** |
1117 | * throtl_pending_timer_fn - timer function for service_queue->pending_timer | |
1118 | * @arg: the throtl_service_queue being serviced | |
1119 | * | |
1120 | * This timer is armed when a child throtl_grp with active bio's become | |
1121 | * pending and queued on the service_queue's pending_tree and expires when | |
1122 | * the first child throtl_grp should be dispatched. This function | |
2e48a530 TH |
1123 | * dispatches bio's from the children throtl_grps to the parent |
1124 | * service_queue. | |
1125 | * | |
1126 | * If the parent's parent is another throtl_grp, dispatching is propagated | |
1127 | * by either arming its pending_timer or repeating dispatch directly. If | |
1128 | * the top-level service_tree is reached, throtl_data->dispatch_work is | |
1129 | * kicked so that the ready bio's are issued. | |
6e1a5704 | 1130 | */ |
69df0ab0 TH |
1131 | static void throtl_pending_timer_fn(unsigned long arg) |
1132 | { | |
1133 | struct throtl_service_queue *sq = (void *)arg; | |
2e48a530 | 1134 | struct throtl_grp *tg = sq_to_tg(sq); |
69df0ab0 | 1135 | struct throtl_data *td = sq_to_td(sq); |
cb76199c | 1136 | struct request_queue *q = td->queue; |
2e48a530 TH |
1137 | struct throtl_service_queue *parent_sq; |
1138 | bool dispatched; | |
6e1a5704 | 1139 | int ret; |
e43473b7 VG |
1140 | |
1141 | spin_lock_irq(q->queue_lock); | |
c79892c5 SL |
1142 | if (throtl_can_upgrade(td, NULL)) |
1143 | throtl_upgrade_state(td); | |
1144 | ||
2e48a530 TH |
1145 | again: |
1146 | parent_sq = sq->parent_sq; | |
1147 | dispatched = false; | |
e43473b7 | 1148 | |
7f52f98c TH |
1149 | while (true) { |
1150 | throtl_log(sq, "dispatch nr_queued=%u read=%u write=%u", | |
2e48a530 TH |
1151 | sq->nr_queued[READ] + sq->nr_queued[WRITE], |
1152 | sq->nr_queued[READ], sq->nr_queued[WRITE]); | |
7f52f98c TH |
1153 | |
1154 | ret = throtl_select_dispatch(sq); | |
1155 | if (ret) { | |
7f52f98c TH |
1156 | throtl_log(sq, "bios disp=%u", ret); |
1157 | dispatched = true; | |
1158 | } | |
e43473b7 | 1159 | |
7f52f98c TH |
1160 | if (throtl_schedule_next_dispatch(sq, false)) |
1161 | break; | |
e43473b7 | 1162 | |
7f52f98c TH |
1163 | /* this dispatch windows is still open, relax and repeat */ |
1164 | spin_unlock_irq(q->queue_lock); | |
1165 | cpu_relax(); | |
1166 | spin_lock_irq(q->queue_lock); | |
651930bc | 1167 | } |
e43473b7 | 1168 | |
2e48a530 TH |
1169 | if (!dispatched) |
1170 | goto out_unlock; | |
6e1a5704 | 1171 | |
2e48a530 TH |
1172 | if (parent_sq) { |
1173 | /* @parent_sq is another throl_grp, propagate dispatch */ | |
1174 | if (tg->flags & THROTL_TG_WAS_EMPTY) { | |
1175 | tg_update_disptime(tg); | |
1176 | if (!throtl_schedule_next_dispatch(parent_sq, false)) { | |
1177 | /* window is already open, repeat dispatching */ | |
1178 | sq = parent_sq; | |
1179 | tg = sq_to_tg(sq); | |
1180 | goto again; | |
1181 | } | |
1182 | } | |
1183 | } else { | |
1184 | /* reached the top-level, queue issueing */ | |
1185 | queue_work(kthrotld_workqueue, &td->dispatch_work); | |
1186 | } | |
1187 | out_unlock: | |
e43473b7 | 1188 | spin_unlock_irq(q->queue_lock); |
6e1a5704 | 1189 | } |
e43473b7 | 1190 | |
6e1a5704 TH |
1191 | /** |
1192 | * blk_throtl_dispatch_work_fn - work function for throtl_data->dispatch_work | |
1193 | * @work: work item being executed | |
1194 | * | |
1195 | * This function is queued for execution when bio's reach the bio_lists[] | |
1196 | * of throtl_data->service_queue. Those bio's are ready and issued by this | |
1197 | * function. | |
1198 | */ | |
8876e140 | 1199 | static void blk_throtl_dispatch_work_fn(struct work_struct *work) |
6e1a5704 TH |
1200 | { |
1201 | struct throtl_data *td = container_of(work, struct throtl_data, | |
1202 | dispatch_work); | |
1203 | struct throtl_service_queue *td_sq = &td->service_queue; | |
1204 | struct request_queue *q = td->queue; | |
1205 | struct bio_list bio_list_on_stack; | |
1206 | struct bio *bio; | |
1207 | struct blk_plug plug; | |
1208 | int rw; | |
1209 | ||
1210 | bio_list_init(&bio_list_on_stack); | |
1211 | ||
1212 | spin_lock_irq(q->queue_lock); | |
c5cc2070 TH |
1213 | for (rw = READ; rw <= WRITE; rw++) |
1214 | while ((bio = throtl_pop_queued(&td_sq->queued[rw], NULL))) | |
1215 | bio_list_add(&bio_list_on_stack, bio); | |
6e1a5704 TH |
1216 | spin_unlock_irq(q->queue_lock); |
1217 | ||
1218 | if (!bio_list_empty(&bio_list_on_stack)) { | |
69d60eb9 | 1219 | blk_start_plug(&plug); |
e43473b7 VG |
1220 | while((bio = bio_list_pop(&bio_list_on_stack))) |
1221 | generic_make_request(bio); | |
69d60eb9 | 1222 | blk_finish_plug(&plug); |
e43473b7 | 1223 | } |
e43473b7 VG |
1224 | } |
1225 | ||
f95a04af TH |
1226 | static u64 tg_prfill_conf_u64(struct seq_file *sf, struct blkg_policy_data *pd, |
1227 | int off) | |
60c2bc2d | 1228 | { |
f95a04af TH |
1229 | struct throtl_grp *tg = pd_to_tg(pd); |
1230 | u64 v = *(u64 *)((void *)tg + off); | |
60c2bc2d | 1231 | |
2ab5492d | 1232 | if (v == U64_MAX) |
60c2bc2d | 1233 | return 0; |
f95a04af | 1234 | return __blkg_prfill_u64(sf, pd, v); |
60c2bc2d TH |
1235 | } |
1236 | ||
f95a04af TH |
1237 | static u64 tg_prfill_conf_uint(struct seq_file *sf, struct blkg_policy_data *pd, |
1238 | int off) | |
e43473b7 | 1239 | { |
f95a04af TH |
1240 | struct throtl_grp *tg = pd_to_tg(pd); |
1241 | unsigned int v = *(unsigned int *)((void *)tg + off); | |
fe071437 | 1242 | |
2ab5492d | 1243 | if (v == UINT_MAX) |
af133ceb | 1244 | return 0; |
f95a04af | 1245 | return __blkg_prfill_u64(sf, pd, v); |
e43473b7 VG |
1246 | } |
1247 | ||
2da8ca82 | 1248 | static int tg_print_conf_u64(struct seq_file *sf, void *v) |
8e89d13f | 1249 | { |
2da8ca82 TH |
1250 | blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), tg_prfill_conf_u64, |
1251 | &blkcg_policy_throtl, seq_cft(sf)->private, false); | |
af133ceb | 1252 | return 0; |
8e89d13f VG |
1253 | } |
1254 | ||
2da8ca82 | 1255 | static int tg_print_conf_uint(struct seq_file *sf, void *v) |
8e89d13f | 1256 | { |
2da8ca82 TH |
1257 | blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), tg_prfill_conf_uint, |
1258 | &blkcg_policy_throtl, seq_cft(sf)->private, false); | |
af133ceb | 1259 | return 0; |
60c2bc2d TH |
1260 | } |
1261 | ||
69948b07 | 1262 | static void tg_conf_updated(struct throtl_grp *tg) |
60c2bc2d | 1263 | { |
69948b07 | 1264 | struct throtl_service_queue *sq = &tg->service_queue; |
492eb21b | 1265 | struct cgroup_subsys_state *pos_css; |
69948b07 | 1266 | struct blkcg_gq *blkg; |
af133ceb | 1267 | |
fda6f272 TH |
1268 | throtl_log(&tg->service_queue, |
1269 | "limit change rbps=%llu wbps=%llu riops=%u wiops=%u", | |
9f626e37 SL |
1270 | tg_bps_limit(tg, READ), tg_bps_limit(tg, WRITE), |
1271 | tg_iops_limit(tg, READ), tg_iops_limit(tg, WRITE)); | |
632b4493 | 1272 | |
693e751e TH |
1273 | /* |
1274 | * Update has_rules[] flags for the updated tg's subtree. A tg is | |
1275 | * considered to have rules if either the tg itself or any of its | |
1276 | * ancestors has rules. This identifies groups without any | |
1277 | * restrictions in the whole hierarchy and allows them to bypass | |
1278 | * blk-throttle. | |
1279 | */ | |
69948b07 | 1280 | blkg_for_each_descendant_pre(blkg, pos_css, tg_to_blkg(tg)) |
693e751e TH |
1281 | tg_update_has_rules(blkg_to_tg(blkg)); |
1282 | ||
632b4493 TH |
1283 | /* |
1284 | * We're already holding queue_lock and know @tg is valid. Let's | |
1285 | * apply the new config directly. | |
1286 | * | |
1287 | * Restart the slices for both READ and WRITES. It might happen | |
1288 | * that a group's limit are dropped suddenly and we don't want to | |
1289 | * account recently dispatched IO with new low rate. | |
1290 | */ | |
0f3457f6 TH |
1291 | throtl_start_new_slice(tg, 0); |
1292 | throtl_start_new_slice(tg, 1); | |
632b4493 | 1293 | |
5b2c16aa | 1294 | if (tg->flags & THROTL_TG_PENDING) { |
77216b04 | 1295 | tg_update_disptime(tg); |
7f52f98c | 1296 | throtl_schedule_next_dispatch(sq->parent_sq, true); |
632b4493 | 1297 | } |
69948b07 TH |
1298 | } |
1299 | ||
1300 | static ssize_t tg_set_conf(struct kernfs_open_file *of, | |
1301 | char *buf, size_t nbytes, loff_t off, bool is_u64) | |
1302 | { | |
1303 | struct blkcg *blkcg = css_to_blkcg(of_css(of)); | |
1304 | struct blkg_conf_ctx ctx; | |
1305 | struct throtl_grp *tg; | |
1306 | int ret; | |
1307 | u64 v; | |
1308 | ||
1309 | ret = blkg_conf_prep(blkcg, &blkcg_policy_throtl, buf, &ctx); | |
1310 | if (ret) | |
1311 | return ret; | |
1312 | ||
1313 | ret = -EINVAL; | |
1314 | if (sscanf(ctx.body, "%llu", &v) != 1) | |
1315 | goto out_finish; | |
1316 | if (!v) | |
2ab5492d | 1317 | v = U64_MAX; |
69948b07 TH |
1318 | |
1319 | tg = blkg_to_tg(ctx.blkg); | |
1320 | ||
1321 | if (is_u64) | |
1322 | *(u64 *)((void *)tg + of_cft(of)->private) = v; | |
1323 | else | |
1324 | *(unsigned int *)((void *)tg + of_cft(of)->private) = v; | |
60c2bc2d | 1325 | |
69948b07 | 1326 | tg_conf_updated(tg); |
36aa9e5f TH |
1327 | ret = 0; |
1328 | out_finish: | |
60c2bc2d | 1329 | blkg_conf_finish(&ctx); |
36aa9e5f | 1330 | return ret ?: nbytes; |
8e89d13f VG |
1331 | } |
1332 | ||
451af504 TH |
1333 | static ssize_t tg_set_conf_u64(struct kernfs_open_file *of, |
1334 | char *buf, size_t nbytes, loff_t off) | |
60c2bc2d | 1335 | { |
451af504 | 1336 | return tg_set_conf(of, buf, nbytes, off, true); |
60c2bc2d TH |
1337 | } |
1338 | ||
451af504 TH |
1339 | static ssize_t tg_set_conf_uint(struct kernfs_open_file *of, |
1340 | char *buf, size_t nbytes, loff_t off) | |
60c2bc2d | 1341 | { |
451af504 | 1342 | return tg_set_conf(of, buf, nbytes, off, false); |
60c2bc2d TH |
1343 | } |
1344 | ||
880f50e2 | 1345 | static struct cftype throtl_legacy_files[] = { |
60c2bc2d TH |
1346 | { |
1347 | .name = "throttle.read_bps_device", | |
9f626e37 | 1348 | .private = offsetof(struct throtl_grp, bps[READ][LIMIT_MAX]), |
2da8ca82 | 1349 | .seq_show = tg_print_conf_u64, |
451af504 | 1350 | .write = tg_set_conf_u64, |
60c2bc2d TH |
1351 | }, |
1352 | { | |
1353 | .name = "throttle.write_bps_device", | |
9f626e37 | 1354 | .private = offsetof(struct throtl_grp, bps[WRITE][LIMIT_MAX]), |
2da8ca82 | 1355 | .seq_show = tg_print_conf_u64, |
451af504 | 1356 | .write = tg_set_conf_u64, |
60c2bc2d TH |
1357 | }, |
1358 | { | |
1359 | .name = "throttle.read_iops_device", | |
9f626e37 | 1360 | .private = offsetof(struct throtl_grp, iops[READ][LIMIT_MAX]), |
2da8ca82 | 1361 | .seq_show = tg_print_conf_uint, |
451af504 | 1362 | .write = tg_set_conf_uint, |
60c2bc2d TH |
1363 | }, |
1364 | { | |
1365 | .name = "throttle.write_iops_device", | |
9f626e37 | 1366 | .private = offsetof(struct throtl_grp, iops[WRITE][LIMIT_MAX]), |
2da8ca82 | 1367 | .seq_show = tg_print_conf_uint, |
451af504 | 1368 | .write = tg_set_conf_uint, |
60c2bc2d TH |
1369 | }, |
1370 | { | |
1371 | .name = "throttle.io_service_bytes", | |
77ea7338 TH |
1372 | .private = (unsigned long)&blkcg_policy_throtl, |
1373 | .seq_show = blkg_print_stat_bytes, | |
60c2bc2d TH |
1374 | }, |
1375 | { | |
1376 | .name = "throttle.io_serviced", | |
77ea7338 TH |
1377 | .private = (unsigned long)&blkcg_policy_throtl, |
1378 | .seq_show = blkg_print_stat_ios, | |
60c2bc2d TH |
1379 | }, |
1380 | { } /* terminate */ | |
1381 | }; | |
1382 | ||
cd5ab1b0 | 1383 | static u64 tg_prfill_limit(struct seq_file *sf, struct blkg_policy_data *pd, |
2ee867dc TH |
1384 | int off) |
1385 | { | |
1386 | struct throtl_grp *tg = pd_to_tg(pd); | |
1387 | const char *dname = blkg_dev_name(pd->blkg); | |
1388 | char bufs[4][21] = { "max", "max", "max", "max" }; | |
cd5ab1b0 SL |
1389 | u64 bps_dft; |
1390 | unsigned int iops_dft; | |
2ee867dc TH |
1391 | |
1392 | if (!dname) | |
1393 | return 0; | |
9f626e37 | 1394 | |
cd5ab1b0 SL |
1395 | if (off == LIMIT_LOW) { |
1396 | bps_dft = 0; | |
1397 | iops_dft = 0; | |
1398 | } else { | |
1399 | bps_dft = U64_MAX; | |
1400 | iops_dft = UINT_MAX; | |
1401 | } | |
1402 | ||
1403 | if (tg->bps_conf[READ][off] == bps_dft && | |
1404 | tg->bps_conf[WRITE][off] == bps_dft && | |
1405 | tg->iops_conf[READ][off] == iops_dft && | |
1406 | tg->iops_conf[WRITE][off] == iops_dft) | |
2ee867dc TH |
1407 | return 0; |
1408 | ||
cd5ab1b0 | 1409 | if (tg->bps_conf[READ][off] != bps_dft) |
9f626e37 | 1410 | snprintf(bufs[0], sizeof(bufs[0]), "%llu", |
cd5ab1b0 SL |
1411 | tg->bps_conf[READ][off]); |
1412 | if (tg->bps_conf[WRITE][off] != bps_dft) | |
9f626e37 | 1413 | snprintf(bufs[1], sizeof(bufs[1]), "%llu", |
cd5ab1b0 SL |
1414 | tg->bps_conf[WRITE][off]); |
1415 | if (tg->iops_conf[READ][off] != iops_dft) | |
9f626e37 | 1416 | snprintf(bufs[2], sizeof(bufs[2]), "%u", |
cd5ab1b0 SL |
1417 | tg->iops_conf[READ][off]); |
1418 | if (tg->iops_conf[WRITE][off] != iops_dft) | |
9f626e37 | 1419 | snprintf(bufs[3], sizeof(bufs[3]), "%u", |
cd5ab1b0 | 1420 | tg->iops_conf[WRITE][off]); |
2ee867dc TH |
1421 | |
1422 | seq_printf(sf, "%s rbps=%s wbps=%s riops=%s wiops=%s\n", | |
1423 | dname, bufs[0], bufs[1], bufs[2], bufs[3]); | |
1424 | return 0; | |
1425 | } | |
1426 | ||
cd5ab1b0 | 1427 | static int tg_print_limit(struct seq_file *sf, void *v) |
2ee867dc | 1428 | { |
cd5ab1b0 | 1429 | blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), tg_prfill_limit, |
2ee867dc TH |
1430 | &blkcg_policy_throtl, seq_cft(sf)->private, false); |
1431 | return 0; | |
1432 | } | |
1433 | ||
cd5ab1b0 | 1434 | static ssize_t tg_set_limit(struct kernfs_open_file *of, |
2ee867dc TH |
1435 | char *buf, size_t nbytes, loff_t off) |
1436 | { | |
1437 | struct blkcg *blkcg = css_to_blkcg(of_css(of)); | |
1438 | struct blkg_conf_ctx ctx; | |
1439 | struct throtl_grp *tg; | |
1440 | u64 v[4]; | |
1441 | int ret; | |
cd5ab1b0 | 1442 | int index = of_cft(of)->private; |
2ee867dc TH |
1443 | |
1444 | ret = blkg_conf_prep(blkcg, &blkcg_policy_throtl, buf, &ctx); | |
1445 | if (ret) | |
1446 | return ret; | |
1447 | ||
1448 | tg = blkg_to_tg(ctx.blkg); | |
1449 | ||
cd5ab1b0 SL |
1450 | v[0] = tg->bps_conf[READ][index]; |
1451 | v[1] = tg->bps_conf[WRITE][index]; | |
1452 | v[2] = tg->iops_conf[READ][index]; | |
1453 | v[3] = tg->iops_conf[WRITE][index]; | |
2ee867dc TH |
1454 | |
1455 | while (true) { | |
1456 | char tok[27]; /* wiops=18446744073709551616 */ | |
1457 | char *p; | |
2ab5492d | 1458 | u64 val = U64_MAX; |
2ee867dc TH |
1459 | int len; |
1460 | ||
1461 | if (sscanf(ctx.body, "%26s%n", tok, &len) != 1) | |
1462 | break; | |
1463 | if (tok[0] == '\0') | |
1464 | break; | |
1465 | ctx.body += len; | |
1466 | ||
1467 | ret = -EINVAL; | |
1468 | p = tok; | |
1469 | strsep(&p, "="); | |
1470 | if (!p || (sscanf(p, "%llu", &val) != 1 && strcmp(p, "max"))) | |
1471 | goto out_finish; | |
1472 | ||
1473 | ret = -ERANGE; | |
1474 | if (!val) | |
1475 | goto out_finish; | |
1476 | ||
1477 | ret = -EINVAL; | |
1478 | if (!strcmp(tok, "rbps")) | |
1479 | v[0] = val; | |
1480 | else if (!strcmp(tok, "wbps")) | |
1481 | v[1] = val; | |
1482 | else if (!strcmp(tok, "riops")) | |
1483 | v[2] = min_t(u64, val, UINT_MAX); | |
1484 | else if (!strcmp(tok, "wiops")) | |
1485 | v[3] = min_t(u64, val, UINT_MAX); | |
1486 | else | |
1487 | goto out_finish; | |
1488 | } | |
1489 | ||
cd5ab1b0 SL |
1490 | tg->bps_conf[READ][index] = v[0]; |
1491 | tg->bps_conf[WRITE][index] = v[1]; | |
1492 | tg->iops_conf[READ][index] = v[2]; | |
1493 | tg->iops_conf[WRITE][index] = v[3]; | |
2ee867dc | 1494 | |
cd5ab1b0 SL |
1495 | if (index == LIMIT_MAX) { |
1496 | tg->bps[READ][index] = v[0]; | |
1497 | tg->bps[WRITE][index] = v[1]; | |
1498 | tg->iops[READ][index] = v[2]; | |
1499 | tg->iops[WRITE][index] = v[3]; | |
1500 | } | |
1501 | tg->bps[READ][LIMIT_LOW] = min(tg->bps_conf[READ][LIMIT_LOW], | |
1502 | tg->bps_conf[READ][LIMIT_MAX]); | |
1503 | tg->bps[WRITE][LIMIT_LOW] = min(tg->bps_conf[WRITE][LIMIT_LOW], | |
1504 | tg->bps_conf[WRITE][LIMIT_MAX]); | |
1505 | tg->iops[READ][LIMIT_LOW] = min(tg->iops_conf[READ][LIMIT_LOW], | |
1506 | tg->iops_conf[READ][LIMIT_MAX]); | |
1507 | tg->iops[WRITE][LIMIT_LOW] = min(tg->iops_conf[WRITE][LIMIT_LOW], | |
1508 | tg->iops_conf[WRITE][LIMIT_MAX]); | |
1509 | ||
1510 | if (index == LIMIT_LOW) { | |
1511 | blk_throtl_update_limit_valid(tg->td); | |
1512 | if (tg->td->limit_valid[LIMIT_LOW]) | |
1513 | tg->td->limit_index = LIMIT_LOW; | |
1514 | } | |
2ee867dc TH |
1515 | tg_conf_updated(tg); |
1516 | ret = 0; | |
1517 | out_finish: | |
1518 | blkg_conf_finish(&ctx); | |
1519 | return ret ?: nbytes; | |
1520 | } | |
1521 | ||
1522 | static struct cftype throtl_files[] = { | |
cd5ab1b0 SL |
1523 | #ifdef CONFIG_BLK_DEV_THROTTLING_LOW |
1524 | { | |
1525 | .name = "low", | |
1526 | .flags = CFTYPE_NOT_ON_ROOT, | |
1527 | .seq_show = tg_print_limit, | |
1528 | .write = tg_set_limit, | |
1529 | .private = LIMIT_LOW, | |
1530 | }, | |
1531 | #endif | |
2ee867dc TH |
1532 | { |
1533 | .name = "max", | |
1534 | .flags = CFTYPE_NOT_ON_ROOT, | |
cd5ab1b0 SL |
1535 | .seq_show = tg_print_limit, |
1536 | .write = tg_set_limit, | |
1537 | .private = LIMIT_MAX, | |
2ee867dc TH |
1538 | }, |
1539 | { } /* terminate */ | |
1540 | }; | |
1541 | ||
da527770 | 1542 | static void throtl_shutdown_wq(struct request_queue *q) |
e43473b7 VG |
1543 | { |
1544 | struct throtl_data *td = q->td; | |
1545 | ||
69df0ab0 | 1546 | cancel_work_sync(&td->dispatch_work); |
e43473b7 VG |
1547 | } |
1548 | ||
3c798398 | 1549 | static struct blkcg_policy blkcg_policy_throtl = { |
2ee867dc | 1550 | .dfl_cftypes = throtl_files, |
880f50e2 | 1551 | .legacy_cftypes = throtl_legacy_files, |
f9fcc2d3 | 1552 | |
001bea73 | 1553 | .pd_alloc_fn = throtl_pd_alloc, |
f9fcc2d3 | 1554 | .pd_init_fn = throtl_pd_init, |
693e751e | 1555 | .pd_online_fn = throtl_pd_online, |
cd5ab1b0 | 1556 | .pd_offline_fn = throtl_pd_offline, |
001bea73 | 1557 | .pd_free_fn = throtl_pd_free, |
e43473b7 VG |
1558 | }; |
1559 | ||
3f0abd80 SL |
1560 | static unsigned long __tg_last_low_overflow_time(struct throtl_grp *tg) |
1561 | { | |
1562 | unsigned long rtime = jiffies, wtime = jiffies; | |
1563 | ||
1564 | if (tg->bps[READ][LIMIT_LOW] || tg->iops[READ][LIMIT_LOW]) | |
1565 | rtime = tg->last_low_overflow_time[READ]; | |
1566 | if (tg->bps[WRITE][LIMIT_LOW] || tg->iops[WRITE][LIMIT_LOW]) | |
1567 | wtime = tg->last_low_overflow_time[WRITE]; | |
1568 | return min(rtime, wtime); | |
1569 | } | |
1570 | ||
1571 | /* tg should not be an intermediate node */ | |
1572 | static unsigned long tg_last_low_overflow_time(struct throtl_grp *tg) | |
1573 | { | |
1574 | struct throtl_service_queue *parent_sq; | |
1575 | struct throtl_grp *parent = tg; | |
1576 | unsigned long ret = __tg_last_low_overflow_time(tg); | |
1577 | ||
1578 | while (true) { | |
1579 | parent_sq = parent->service_queue.parent_sq; | |
1580 | parent = sq_to_tg(parent_sq); | |
1581 | if (!parent) | |
1582 | break; | |
1583 | ||
1584 | /* | |
1585 | * The parent doesn't have low limit, it always reaches low | |
1586 | * limit. Its overflow time is useless for children | |
1587 | */ | |
1588 | if (!parent->bps[READ][LIMIT_LOW] && | |
1589 | !parent->iops[READ][LIMIT_LOW] && | |
1590 | !parent->bps[WRITE][LIMIT_LOW] && | |
1591 | !parent->iops[WRITE][LIMIT_LOW]) | |
1592 | continue; | |
1593 | if (time_after(__tg_last_low_overflow_time(parent), ret)) | |
1594 | ret = __tg_last_low_overflow_time(parent); | |
1595 | } | |
1596 | return ret; | |
1597 | } | |
1598 | ||
c79892c5 SL |
1599 | static bool throtl_tg_can_upgrade(struct throtl_grp *tg) |
1600 | { | |
1601 | struct throtl_service_queue *sq = &tg->service_queue; | |
1602 | bool read_limit, write_limit; | |
1603 | ||
1604 | /* | |
1605 | * if cgroup reaches low limit (if low limit is 0, the cgroup always | |
1606 | * reaches), it's ok to upgrade to next limit | |
1607 | */ | |
1608 | read_limit = tg->bps[READ][LIMIT_LOW] || tg->iops[READ][LIMIT_LOW]; | |
1609 | write_limit = tg->bps[WRITE][LIMIT_LOW] || tg->iops[WRITE][LIMIT_LOW]; | |
1610 | if (!read_limit && !write_limit) | |
1611 | return true; | |
1612 | if (read_limit && sq->nr_queued[READ] && | |
1613 | (!write_limit || sq->nr_queued[WRITE])) | |
1614 | return true; | |
1615 | if (write_limit && sq->nr_queued[WRITE] && | |
1616 | (!read_limit || sq->nr_queued[READ])) | |
1617 | return true; | |
1618 | return false; | |
1619 | } | |
1620 | ||
1621 | static bool throtl_hierarchy_can_upgrade(struct throtl_grp *tg) | |
1622 | { | |
1623 | while (true) { | |
1624 | if (throtl_tg_can_upgrade(tg)) | |
1625 | return true; | |
1626 | tg = sq_to_tg(tg->service_queue.parent_sq); | |
1627 | if (!tg || !tg_to_blkg(tg)->parent) | |
1628 | return false; | |
1629 | } | |
1630 | return false; | |
1631 | } | |
1632 | ||
1633 | static bool throtl_can_upgrade(struct throtl_data *td, | |
1634 | struct throtl_grp *this_tg) | |
1635 | { | |
1636 | struct cgroup_subsys_state *pos_css; | |
1637 | struct blkcg_gq *blkg; | |
1638 | ||
1639 | if (td->limit_index != LIMIT_LOW) | |
1640 | return false; | |
1641 | ||
297e3d85 | 1642 | if (time_before(jiffies, td->low_downgrade_time + td->throtl_slice)) |
3f0abd80 SL |
1643 | return false; |
1644 | ||
c79892c5 SL |
1645 | rcu_read_lock(); |
1646 | blkg_for_each_descendant_post(blkg, pos_css, td->queue->root_blkg) { | |
1647 | struct throtl_grp *tg = blkg_to_tg(blkg); | |
1648 | ||
1649 | if (tg == this_tg) | |
1650 | continue; | |
1651 | if (!list_empty(&tg_to_blkg(tg)->blkcg->css.children)) | |
1652 | continue; | |
1653 | if (!throtl_hierarchy_can_upgrade(tg)) { | |
1654 | rcu_read_unlock(); | |
1655 | return false; | |
1656 | } | |
1657 | } | |
1658 | rcu_read_unlock(); | |
1659 | return true; | |
1660 | } | |
1661 | ||
1662 | static void throtl_upgrade_state(struct throtl_data *td) | |
1663 | { | |
1664 | struct cgroup_subsys_state *pos_css; | |
1665 | struct blkcg_gq *blkg; | |
1666 | ||
1667 | td->limit_index = LIMIT_MAX; | |
3f0abd80 | 1668 | td->low_upgrade_time = jiffies; |
c79892c5 SL |
1669 | rcu_read_lock(); |
1670 | blkg_for_each_descendant_post(blkg, pos_css, td->queue->root_blkg) { | |
1671 | struct throtl_grp *tg = blkg_to_tg(blkg); | |
1672 | struct throtl_service_queue *sq = &tg->service_queue; | |
1673 | ||
1674 | tg->disptime = jiffies - 1; | |
1675 | throtl_select_dispatch(sq); | |
1676 | throtl_schedule_next_dispatch(sq, false); | |
1677 | } | |
1678 | rcu_read_unlock(); | |
1679 | throtl_select_dispatch(&td->service_queue); | |
1680 | throtl_schedule_next_dispatch(&td->service_queue, false); | |
1681 | queue_work(kthrotld_workqueue, &td->dispatch_work); | |
1682 | } | |
1683 | ||
3f0abd80 SL |
1684 | static void throtl_downgrade_state(struct throtl_data *td, int new) |
1685 | { | |
1686 | td->limit_index = new; | |
1687 | td->low_downgrade_time = jiffies; | |
1688 | } | |
1689 | ||
1690 | static bool throtl_tg_can_downgrade(struct throtl_grp *tg) | |
1691 | { | |
1692 | struct throtl_data *td = tg->td; | |
1693 | unsigned long now = jiffies; | |
1694 | ||
1695 | /* | |
1696 | * If cgroup is below low limit, consider downgrade and throttle other | |
1697 | * cgroups | |
1698 | */ | |
297e3d85 SL |
1699 | if (time_after_eq(now, td->low_upgrade_time + td->throtl_slice) && |
1700 | time_after_eq(now, tg_last_low_overflow_time(tg) + | |
1701 | td->throtl_slice)) | |
3f0abd80 SL |
1702 | return true; |
1703 | return false; | |
1704 | } | |
1705 | ||
1706 | static bool throtl_hierarchy_can_downgrade(struct throtl_grp *tg) | |
1707 | { | |
1708 | while (true) { | |
1709 | if (!throtl_tg_can_downgrade(tg)) | |
1710 | return false; | |
1711 | tg = sq_to_tg(tg->service_queue.parent_sq); | |
1712 | if (!tg || !tg_to_blkg(tg)->parent) | |
1713 | break; | |
1714 | } | |
1715 | return true; | |
1716 | } | |
1717 | ||
1718 | static void throtl_downgrade_check(struct throtl_grp *tg) | |
1719 | { | |
1720 | uint64_t bps; | |
1721 | unsigned int iops; | |
1722 | unsigned long elapsed_time; | |
1723 | unsigned long now = jiffies; | |
1724 | ||
1725 | if (tg->td->limit_index != LIMIT_MAX || | |
1726 | !tg->td->limit_valid[LIMIT_LOW]) | |
1727 | return; | |
1728 | if (!list_empty(&tg_to_blkg(tg)->blkcg->css.children)) | |
1729 | return; | |
297e3d85 | 1730 | if (time_after(tg->last_check_time + tg->td->throtl_slice, now)) |
3f0abd80 SL |
1731 | return; |
1732 | ||
1733 | elapsed_time = now - tg->last_check_time; | |
1734 | tg->last_check_time = now; | |
1735 | ||
297e3d85 SL |
1736 | if (time_before(now, tg_last_low_overflow_time(tg) + |
1737 | tg->td->throtl_slice)) | |
3f0abd80 SL |
1738 | return; |
1739 | ||
1740 | if (tg->bps[READ][LIMIT_LOW]) { | |
1741 | bps = tg->last_bytes_disp[READ] * HZ; | |
1742 | do_div(bps, elapsed_time); | |
1743 | if (bps >= tg->bps[READ][LIMIT_LOW]) | |
1744 | tg->last_low_overflow_time[READ] = now; | |
1745 | } | |
1746 | ||
1747 | if (tg->bps[WRITE][LIMIT_LOW]) { | |
1748 | bps = tg->last_bytes_disp[WRITE] * HZ; | |
1749 | do_div(bps, elapsed_time); | |
1750 | if (bps >= tg->bps[WRITE][LIMIT_LOW]) | |
1751 | tg->last_low_overflow_time[WRITE] = now; | |
1752 | } | |
1753 | ||
1754 | if (tg->iops[READ][LIMIT_LOW]) { | |
1755 | iops = tg->last_io_disp[READ] * HZ / elapsed_time; | |
1756 | if (iops >= tg->iops[READ][LIMIT_LOW]) | |
1757 | tg->last_low_overflow_time[READ] = now; | |
1758 | } | |
1759 | ||
1760 | if (tg->iops[WRITE][LIMIT_LOW]) { | |
1761 | iops = tg->last_io_disp[WRITE] * HZ / elapsed_time; | |
1762 | if (iops >= tg->iops[WRITE][LIMIT_LOW]) | |
1763 | tg->last_low_overflow_time[WRITE] = now; | |
1764 | } | |
1765 | ||
1766 | /* | |
1767 | * If cgroup is below low limit, consider downgrade and throttle other | |
1768 | * cgroups | |
1769 | */ | |
1770 | if (throtl_hierarchy_can_downgrade(tg)) | |
1771 | throtl_downgrade_state(tg->td, LIMIT_LOW); | |
1772 | ||
1773 | tg->last_bytes_disp[READ] = 0; | |
1774 | tg->last_bytes_disp[WRITE] = 0; | |
1775 | tg->last_io_disp[READ] = 0; | |
1776 | tg->last_io_disp[WRITE] = 0; | |
1777 | } | |
1778 | ||
ae118896 TH |
1779 | bool blk_throtl_bio(struct request_queue *q, struct blkcg_gq *blkg, |
1780 | struct bio *bio) | |
e43473b7 | 1781 | { |
c5cc2070 | 1782 | struct throtl_qnode *qn = NULL; |
ae118896 | 1783 | struct throtl_grp *tg = blkg_to_tg(blkg ?: q->root_blkg); |
73f0d49a | 1784 | struct throtl_service_queue *sq; |
0e9f4164 | 1785 | bool rw = bio_data_dir(bio); |
bc16a4f9 | 1786 | bool throttled = false; |
e43473b7 | 1787 | |
ae118896 TH |
1788 | WARN_ON_ONCE(!rcu_read_lock_held()); |
1789 | ||
2a0f61e6 | 1790 | /* see throtl_charge_bio() */ |
8d2bbd4c | 1791 | if (bio_flagged(bio, BIO_THROTTLED) || !tg->has_rules[rw]) |
bc16a4f9 | 1792 | goto out; |
e43473b7 VG |
1793 | |
1794 | spin_lock_irq(q->queue_lock); | |
c9589f03 TH |
1795 | |
1796 | if (unlikely(blk_queue_bypass(q))) | |
bc16a4f9 | 1797 | goto out_unlock; |
f469a7b4 | 1798 | |
73f0d49a TH |
1799 | sq = &tg->service_queue; |
1800 | ||
c79892c5 | 1801 | again: |
9e660acf | 1802 | while (true) { |
3f0abd80 SL |
1803 | if (tg->last_low_overflow_time[rw] == 0) |
1804 | tg->last_low_overflow_time[rw] = jiffies; | |
1805 | throtl_downgrade_check(tg); | |
9e660acf TH |
1806 | /* throtl is FIFO - if bios are already queued, should queue */ |
1807 | if (sq->nr_queued[rw]) | |
1808 | break; | |
de701c74 | 1809 | |
9e660acf | 1810 | /* if above limits, break to queue */ |
c79892c5 | 1811 | if (!tg_may_dispatch(tg, bio, NULL)) { |
3f0abd80 | 1812 | tg->last_low_overflow_time[rw] = jiffies; |
c79892c5 SL |
1813 | if (throtl_can_upgrade(tg->td, tg)) { |
1814 | throtl_upgrade_state(tg->td); | |
1815 | goto again; | |
1816 | } | |
9e660acf | 1817 | break; |
c79892c5 | 1818 | } |
9e660acf TH |
1819 | |
1820 | /* within limits, let's charge and dispatch directly */ | |
e43473b7 | 1821 | throtl_charge_bio(tg, bio); |
04521db0 VG |
1822 | |
1823 | /* | |
1824 | * We need to trim slice even when bios are not being queued | |
1825 | * otherwise it might happen that a bio is not queued for | |
1826 | * a long time and slice keeps on extending and trim is not | |
1827 | * called for a long time. Now if limits are reduced suddenly | |
1828 | * we take into account all the IO dispatched so far at new | |
1829 | * low rate and * newly queued IO gets a really long dispatch | |
1830 | * time. | |
1831 | * | |
1832 | * So keep on trimming slice even if bio is not queued. | |
1833 | */ | |
0f3457f6 | 1834 | throtl_trim_slice(tg, rw); |
9e660acf TH |
1835 | |
1836 | /* | |
1837 | * @bio passed through this layer without being throttled. | |
1838 | * Climb up the ladder. If we''re already at the top, it | |
1839 | * can be executed directly. | |
1840 | */ | |
c5cc2070 | 1841 | qn = &tg->qnode_on_parent[rw]; |
9e660acf TH |
1842 | sq = sq->parent_sq; |
1843 | tg = sq_to_tg(sq); | |
1844 | if (!tg) | |
1845 | goto out_unlock; | |
e43473b7 VG |
1846 | } |
1847 | ||
9e660acf | 1848 | /* out-of-limit, queue to @tg */ |
fda6f272 TH |
1849 | throtl_log(sq, "[%c] bio. bdisp=%llu sz=%u bps=%llu iodisp=%u iops=%u queued=%d/%d", |
1850 | rw == READ ? 'R' : 'W', | |
9f626e37 SL |
1851 | tg->bytes_disp[rw], bio->bi_iter.bi_size, |
1852 | tg_bps_limit(tg, rw), | |
1853 | tg->io_disp[rw], tg_iops_limit(tg, rw), | |
fda6f272 | 1854 | sq->nr_queued[READ], sq->nr_queued[WRITE]); |
e43473b7 | 1855 | |
3f0abd80 SL |
1856 | tg->last_low_overflow_time[rw] = jiffies; |
1857 | ||
671058fb | 1858 | bio_associate_current(bio); |
6bc9c2b4 | 1859 | tg->td->nr_queued[rw]++; |
c5cc2070 | 1860 | throtl_add_bio_tg(bio, qn, tg); |
bc16a4f9 | 1861 | throttled = true; |
e43473b7 | 1862 | |
7f52f98c TH |
1863 | /* |
1864 | * Update @tg's dispatch time and force schedule dispatch if @tg | |
1865 | * was empty before @bio. The forced scheduling isn't likely to | |
1866 | * cause undue delay as @bio is likely to be dispatched directly if | |
1867 | * its @tg's disptime is not in the future. | |
1868 | */ | |
0e9f4164 | 1869 | if (tg->flags & THROTL_TG_WAS_EMPTY) { |
77216b04 | 1870 | tg_update_disptime(tg); |
7f52f98c | 1871 | throtl_schedule_next_dispatch(tg->service_queue.parent_sq, true); |
e43473b7 VG |
1872 | } |
1873 | ||
bc16a4f9 | 1874 | out_unlock: |
e43473b7 | 1875 | spin_unlock_irq(q->queue_lock); |
bc16a4f9 | 1876 | out: |
2a0f61e6 TH |
1877 | /* |
1878 | * As multiple blk-throtls may stack in the same issue path, we | |
1879 | * don't want bios to leave with the flag set. Clear the flag if | |
1880 | * being issued. | |
1881 | */ | |
1882 | if (!throttled) | |
8d2bbd4c | 1883 | bio_clear_flag(bio, BIO_THROTTLED); |
bc16a4f9 | 1884 | return throttled; |
e43473b7 VG |
1885 | } |
1886 | ||
2a12f0dc TH |
1887 | /* |
1888 | * Dispatch all bios from all children tg's queued on @parent_sq. On | |
1889 | * return, @parent_sq is guaranteed to not have any active children tg's | |
1890 | * and all bios from previously active tg's are on @parent_sq->bio_lists[]. | |
1891 | */ | |
1892 | static void tg_drain_bios(struct throtl_service_queue *parent_sq) | |
1893 | { | |
1894 | struct throtl_grp *tg; | |
1895 | ||
1896 | while ((tg = throtl_rb_first(parent_sq))) { | |
1897 | struct throtl_service_queue *sq = &tg->service_queue; | |
1898 | struct bio *bio; | |
1899 | ||
1900 | throtl_dequeue_tg(tg); | |
1901 | ||
c5cc2070 | 1902 | while ((bio = throtl_peek_queued(&sq->queued[READ]))) |
2a12f0dc | 1903 | tg_dispatch_one_bio(tg, bio_data_dir(bio)); |
c5cc2070 | 1904 | while ((bio = throtl_peek_queued(&sq->queued[WRITE]))) |
2a12f0dc TH |
1905 | tg_dispatch_one_bio(tg, bio_data_dir(bio)); |
1906 | } | |
1907 | } | |
1908 | ||
c9a929dd TH |
1909 | /** |
1910 | * blk_throtl_drain - drain throttled bios | |
1911 | * @q: request_queue to drain throttled bios for | |
1912 | * | |
1913 | * Dispatch all currently throttled bios on @q through ->make_request_fn(). | |
1914 | */ | |
1915 | void blk_throtl_drain(struct request_queue *q) | |
1916 | __releases(q->queue_lock) __acquires(q->queue_lock) | |
1917 | { | |
1918 | struct throtl_data *td = q->td; | |
2a12f0dc | 1919 | struct blkcg_gq *blkg; |
492eb21b | 1920 | struct cgroup_subsys_state *pos_css; |
c9a929dd | 1921 | struct bio *bio; |
651930bc | 1922 | int rw; |
c9a929dd | 1923 | |
8bcb6c7d | 1924 | queue_lockdep_assert_held(q); |
2a12f0dc | 1925 | rcu_read_lock(); |
c9a929dd | 1926 | |
2a12f0dc TH |
1927 | /* |
1928 | * Drain each tg while doing post-order walk on the blkg tree, so | |
1929 | * that all bios are propagated to td->service_queue. It'd be | |
1930 | * better to walk service_queue tree directly but blkg walk is | |
1931 | * easier. | |
1932 | */ | |
492eb21b | 1933 | blkg_for_each_descendant_post(blkg, pos_css, td->queue->root_blkg) |
2a12f0dc | 1934 | tg_drain_bios(&blkg_to_tg(blkg)->service_queue); |
73f0d49a | 1935 | |
2a12f0dc TH |
1936 | /* finally, transfer bios from top-level tg's into the td */ |
1937 | tg_drain_bios(&td->service_queue); | |
1938 | ||
1939 | rcu_read_unlock(); | |
c9a929dd TH |
1940 | spin_unlock_irq(q->queue_lock); |
1941 | ||
2a12f0dc | 1942 | /* all bios now should be in td->service_queue, issue them */ |
651930bc | 1943 | for (rw = READ; rw <= WRITE; rw++) |
c5cc2070 TH |
1944 | while ((bio = throtl_pop_queued(&td->service_queue.queued[rw], |
1945 | NULL))) | |
651930bc | 1946 | generic_make_request(bio); |
c9a929dd TH |
1947 | |
1948 | spin_lock_irq(q->queue_lock); | |
1949 | } | |
1950 | ||
e43473b7 VG |
1951 | int blk_throtl_init(struct request_queue *q) |
1952 | { | |
1953 | struct throtl_data *td; | |
a2b1693b | 1954 | int ret; |
e43473b7 VG |
1955 | |
1956 | td = kzalloc_node(sizeof(*td), GFP_KERNEL, q->node); | |
1957 | if (!td) | |
1958 | return -ENOMEM; | |
1959 | ||
69df0ab0 | 1960 | INIT_WORK(&td->dispatch_work, blk_throtl_dispatch_work_fn); |
b2ce2643 | 1961 | throtl_service_queue_init(&td->service_queue); |
e43473b7 | 1962 | |
cd1604fa | 1963 | q->td = td; |
29b12589 | 1964 | td->queue = q; |
02977e4a | 1965 | |
9f626e37 | 1966 | td->limit_valid[LIMIT_MAX] = true; |
cd5ab1b0 | 1967 | td->limit_index = LIMIT_MAX; |
3f0abd80 SL |
1968 | td->low_upgrade_time = jiffies; |
1969 | td->low_downgrade_time = jiffies; | |
a2b1693b | 1970 | /* activate policy */ |
3c798398 | 1971 | ret = blkcg_activate_policy(q, &blkcg_policy_throtl); |
a2b1693b | 1972 | if (ret) |
f51b802c | 1973 | kfree(td); |
a2b1693b | 1974 | return ret; |
e43473b7 VG |
1975 | } |
1976 | ||
1977 | void blk_throtl_exit(struct request_queue *q) | |
1978 | { | |
c875f4d0 | 1979 | BUG_ON(!q->td); |
da527770 | 1980 | throtl_shutdown_wq(q); |
3c798398 | 1981 | blkcg_deactivate_policy(q, &blkcg_policy_throtl); |
c9a929dd | 1982 | kfree(q->td); |
e43473b7 VG |
1983 | } |
1984 | ||
d61fcfa4 SL |
1985 | void blk_throtl_register_queue(struct request_queue *q) |
1986 | { | |
1987 | struct throtl_data *td; | |
1988 | ||
1989 | td = q->td; | |
1990 | BUG_ON(!td); | |
1991 | ||
1992 | if (blk_queue_nonrot(q)) | |
1993 | td->throtl_slice = DFL_THROTL_SLICE_SSD; | |
1994 | else | |
1995 | td->throtl_slice = DFL_THROTL_SLICE_HD; | |
1996 | #ifndef CONFIG_BLK_DEV_THROTTLING_LOW | |
1997 | /* if no low limit, use previous default */ | |
1998 | td->throtl_slice = DFL_THROTL_SLICE_HD; | |
1999 | #endif | |
2000 | } | |
2001 | ||
297e3d85 SL |
2002 | #ifdef CONFIG_BLK_DEV_THROTTLING_LOW |
2003 | ssize_t blk_throtl_sample_time_show(struct request_queue *q, char *page) | |
2004 | { | |
2005 | if (!q->td) | |
2006 | return -EINVAL; | |
2007 | return sprintf(page, "%u\n", jiffies_to_msecs(q->td->throtl_slice)); | |
2008 | } | |
2009 | ||
2010 | ssize_t blk_throtl_sample_time_store(struct request_queue *q, | |
2011 | const char *page, size_t count) | |
2012 | { | |
2013 | unsigned long v; | |
2014 | unsigned long t; | |
2015 | ||
2016 | if (!q->td) | |
2017 | return -EINVAL; | |
2018 | if (kstrtoul(page, 10, &v)) | |
2019 | return -EINVAL; | |
2020 | t = msecs_to_jiffies(v); | |
2021 | if (t == 0 || t > MAX_THROTL_SLICE) | |
2022 | return -EINVAL; | |
2023 | q->td->throtl_slice = t; | |
2024 | return count; | |
2025 | } | |
2026 | #endif | |
2027 | ||
e43473b7 VG |
2028 | static int __init throtl_init(void) |
2029 | { | |
450adcbe VG |
2030 | kthrotld_workqueue = alloc_workqueue("kthrotld", WQ_MEM_RECLAIM, 0); |
2031 | if (!kthrotld_workqueue) | |
2032 | panic("Failed to create kthrotld\n"); | |
2033 | ||
3c798398 | 2034 | return blkcg_policy_register(&blkcg_policy_throtl); |
e43473b7 VG |
2035 | } |
2036 | ||
2037 | module_init(throtl_init); |