Commit | Line | Data |
---|---|---|
75bb4625 JA |
1 | /* |
2 | * Fast and scalable bitmap tagging variant. Uses sparser bitmaps spread | |
3 | * over multiple cachelines to avoid ping-pong between multiple submitters | |
4 | * or submitter and completer. Uses rolling wakeups to avoid falling of | |
5 | * the scaling cliff when we run out of tags and have to start putting | |
6 | * submitters to sleep. | |
7 | * | |
8 | * Uses active queue tracking to support fairer distribution of tags | |
9 | * between multiple submitters when a shared tag map is used. | |
10 | * | |
11 | * Copyright (C) 2013-2014 Jens Axboe | |
12 | */ | |
320ae51f JA |
13 | #include <linux/kernel.h> |
14 | #include <linux/module.h> | |
4bb659b1 | 15 | #include <linux/random.h> |
320ae51f JA |
16 | |
17 | #include <linux/blk-mq.h> | |
18 | #include "blk.h" | |
19 | #include "blk-mq.h" | |
20 | #include "blk-mq-tag.h" | |
21 | ||
4bb659b1 JA |
22 | static bool bt_has_free_tags(struct blk_mq_bitmap_tags *bt) |
23 | { | |
24 | int i; | |
25 | ||
26 | for (i = 0; i < bt->map_nr; i++) { | |
e93ecf60 | 27 | struct blk_align_bitmap *bm = &bt->map[i]; |
4bb659b1 JA |
28 | int ret; |
29 | ||
30 | ret = find_first_zero_bit(&bm->word, bm->depth); | |
31 | if (ret < bm->depth) | |
32 | return true; | |
33 | } | |
34 | ||
35 | return false; | |
320ae51f JA |
36 | } |
37 | ||
38 | bool blk_mq_has_free_tags(struct blk_mq_tags *tags) | |
39 | { | |
4bb659b1 JA |
40 | if (!tags) |
41 | return true; | |
42 | ||
43 | return bt_has_free_tags(&tags->bitmap_tags); | |
44 | } | |
45 | ||
8537b120 | 46 | static inline int bt_index_inc(int index) |
0d2602ca | 47 | { |
8537b120 AG |
48 | return (index + 1) & (BT_WAIT_QUEUES - 1); |
49 | } | |
50 | ||
51 | static inline void bt_index_atomic_inc(atomic_t *index) | |
52 | { | |
53 | int old = atomic_read(index); | |
54 | int new = bt_index_inc(old); | |
55 | atomic_cmpxchg(index, old, new); | |
0d2602ca JA |
56 | } |
57 | ||
58 | /* | |
59 | * If a previously inactive queue goes active, bump the active user count. | |
60 | */ | |
61 | bool __blk_mq_tag_busy(struct blk_mq_hw_ctx *hctx) | |
62 | { | |
63 | if (!test_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state) && | |
64 | !test_and_set_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state)) | |
65 | atomic_inc(&hctx->tags->active_queues); | |
66 | ||
67 | return true; | |
68 | } | |
69 | ||
70 | /* | |
aed3ea94 | 71 | * Wakeup all potentially sleeping on tags |
0d2602ca | 72 | */ |
aed3ea94 | 73 | void blk_mq_tag_wakeup_all(struct blk_mq_tags *tags, bool include_reserve) |
0d2602ca | 74 | { |
0d2602ca JA |
75 | struct blk_mq_bitmap_tags *bt; |
76 | int i, wake_index; | |
77 | ||
0d2602ca | 78 | bt = &tags->bitmap_tags; |
8537b120 | 79 | wake_index = atomic_read(&bt->wake_index); |
0d2602ca JA |
80 | for (i = 0; i < BT_WAIT_QUEUES; i++) { |
81 | struct bt_wait_state *bs = &bt->bs[wake_index]; | |
82 | ||
83 | if (waitqueue_active(&bs->wait)) | |
84 | wake_up(&bs->wait); | |
85 | ||
8537b120 | 86 | wake_index = bt_index_inc(wake_index); |
0d2602ca | 87 | } |
aed3ea94 JA |
88 | |
89 | if (include_reserve) { | |
90 | bt = &tags->breserved_tags; | |
91 | if (waitqueue_active(&bt->bs[0].wait)) | |
92 | wake_up(&bt->bs[0].wait); | |
93 | } | |
0d2602ca JA |
94 | } |
95 | ||
e3a2b3f9 JA |
96 | /* |
97 | * If a previously busy queue goes inactive, potential waiters could now | |
98 | * be allowed to queue. Wake them up and check. | |
99 | */ | |
100 | void __blk_mq_tag_idle(struct blk_mq_hw_ctx *hctx) | |
101 | { | |
102 | struct blk_mq_tags *tags = hctx->tags; | |
103 | ||
104 | if (!test_and_clear_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state)) | |
105 | return; | |
106 | ||
107 | atomic_dec(&tags->active_queues); | |
108 | ||
aed3ea94 | 109 | blk_mq_tag_wakeup_all(tags, false); |
e3a2b3f9 JA |
110 | } |
111 | ||
0d2602ca JA |
112 | /* |
113 | * For shared tag users, we track the number of currently active users | |
114 | * and attempt to provide a fair share of the tag depth for each of them. | |
115 | */ | |
116 | static inline bool hctx_may_queue(struct blk_mq_hw_ctx *hctx, | |
117 | struct blk_mq_bitmap_tags *bt) | |
118 | { | |
119 | unsigned int depth, users; | |
120 | ||
121 | if (!hctx || !(hctx->flags & BLK_MQ_F_TAG_SHARED)) | |
122 | return true; | |
123 | if (!test_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state)) | |
124 | return true; | |
125 | ||
126 | /* | |
127 | * Don't try dividing an ant | |
128 | */ | |
129 | if (bt->depth == 1) | |
130 | return true; | |
131 | ||
132 | users = atomic_read(&hctx->tags->active_queues); | |
133 | if (!users) | |
134 | return true; | |
135 | ||
136 | /* | |
137 | * Allow at least some tags | |
138 | */ | |
139 | depth = max((bt->depth + users - 1) / users, 4U); | |
140 | return atomic_read(&hctx->nr_active) < depth; | |
141 | } | |
142 | ||
24391c0d SL |
143 | static int __bt_get_word(struct blk_align_bitmap *bm, unsigned int last_tag, |
144 | bool nowrap) | |
4bb659b1 | 145 | { |
0bf36498 JA |
146 | int tag, org_last_tag = last_tag; |
147 | ||
148 | while (1) { | |
149 | tag = find_next_zero_bit(&bm->word, bm->depth, last_tag); | |
150 | if (unlikely(tag >= bm->depth)) { | |
4bb659b1 | 151 | /* |
0bf36498 JA |
152 | * We started with an offset, and we didn't reset the |
153 | * offset to 0 in a failure case, so start from 0 to | |
4bb659b1 JA |
154 | * exhaust the map. |
155 | */ | |
24391c0d | 156 | if (org_last_tag && last_tag && !nowrap) { |
0bf36498 JA |
157 | last_tag = org_last_tag = 0; |
158 | continue; | |
4bb659b1 JA |
159 | } |
160 | return -1; | |
161 | } | |
0bf36498 JA |
162 | |
163 | if (!test_and_set_bit(tag, &bm->word)) | |
164 | break; | |
165 | ||
4bb659b1 | 166 | last_tag = tag + 1; |
0bf36498 JA |
167 | if (last_tag >= bm->depth - 1) |
168 | last_tag = 0; | |
169 | } | |
4bb659b1 JA |
170 | |
171 | return tag; | |
172 | } | |
173 | ||
24391c0d SL |
174 | #define BT_ALLOC_RR(tags) (tags->alloc_policy == BLK_TAG_ALLOC_RR) |
175 | ||
4bb659b1 JA |
176 | /* |
177 | * Straight forward bitmap tag implementation, where each bit is a tag | |
178 | * (cleared == free, and set == busy). The small twist is using per-cpu | |
179 | * last_tag caches, which blk-mq stores in the blk_mq_ctx software queue | |
180 | * contexts. This enables us to drastically limit the space searched, | |
181 | * without dirtying an extra shared cacheline like we would if we stored | |
182 | * the cache value inside the shared blk_mq_bitmap_tags structure. On top | |
183 | * of that, each word of tags is in a separate cacheline. This means that | |
184 | * multiple users will tend to stick to different cachelines, at least | |
185 | * until the map is exhausted. | |
186 | */ | |
0d2602ca | 187 | static int __bt_get(struct blk_mq_hw_ctx *hctx, struct blk_mq_bitmap_tags *bt, |
24391c0d | 188 | unsigned int *tag_cache, struct blk_mq_tags *tags) |
4bb659b1 JA |
189 | { |
190 | unsigned int last_tag, org_last_tag; | |
191 | int index, i, tag; | |
192 | ||
0d2602ca JA |
193 | if (!hctx_may_queue(hctx, bt)) |
194 | return -1; | |
195 | ||
4bb659b1 | 196 | last_tag = org_last_tag = *tag_cache; |
59d13bf5 | 197 | index = TAG_TO_INDEX(bt, last_tag); |
4bb659b1 JA |
198 | |
199 | for (i = 0; i < bt->map_nr; i++) { | |
24391c0d SL |
200 | tag = __bt_get_word(&bt->map[index], TAG_TO_BIT(bt, last_tag), |
201 | BT_ALLOC_RR(tags)); | |
4bb659b1 | 202 | if (tag != -1) { |
59d13bf5 | 203 | tag += (index << bt->bits_per_word); |
4bb659b1 JA |
204 | goto done; |
205 | } | |
206 | ||
0bf36498 JA |
207 | /* |
208 | * Jump to next index, and reset the last tag to be the | |
209 | * first tag of that index | |
210 | */ | |
211 | index++; | |
212 | last_tag = (index << bt->bits_per_word); | |
213 | ||
214 | if (index >= bt->map_nr) { | |
4bb659b1 | 215 | index = 0; |
0bf36498 JA |
216 | last_tag = 0; |
217 | } | |
4bb659b1 JA |
218 | } |
219 | ||
220 | *tag_cache = 0; | |
221 | return -1; | |
222 | ||
223 | /* | |
224 | * Only update the cache from the allocation path, if we ended | |
225 | * up using the specific cached tag. | |
226 | */ | |
227 | done: | |
24391c0d | 228 | if (tag == org_last_tag || unlikely(BT_ALLOC_RR(tags))) { |
4bb659b1 JA |
229 | last_tag = tag + 1; |
230 | if (last_tag >= bt->depth - 1) | |
231 | last_tag = 0; | |
232 | ||
233 | *tag_cache = last_tag; | |
234 | } | |
235 | ||
236 | return tag; | |
237 | } | |
238 | ||
4bb659b1 JA |
239 | static struct bt_wait_state *bt_wait_ptr(struct blk_mq_bitmap_tags *bt, |
240 | struct blk_mq_hw_ctx *hctx) | |
241 | { | |
242 | struct bt_wait_state *bs; | |
8537b120 | 243 | int wait_index; |
4bb659b1 JA |
244 | |
245 | if (!hctx) | |
246 | return &bt->bs[0]; | |
247 | ||
8537b120 AG |
248 | wait_index = atomic_read(&hctx->wait_index); |
249 | bs = &bt->bs[wait_index]; | |
250 | bt_index_atomic_inc(&hctx->wait_index); | |
4bb659b1 | 251 | return bs; |
320ae51f JA |
252 | } |
253 | ||
cb96a42c ML |
254 | static int bt_get(struct blk_mq_alloc_data *data, |
255 | struct blk_mq_bitmap_tags *bt, | |
256 | struct blk_mq_hw_ctx *hctx, | |
24391c0d | 257 | unsigned int *last_tag, struct blk_mq_tags *tags) |
320ae51f | 258 | { |
4bb659b1 JA |
259 | struct bt_wait_state *bs; |
260 | DEFINE_WAIT(wait); | |
320ae51f JA |
261 | int tag; |
262 | ||
24391c0d | 263 | tag = __bt_get(hctx, bt, last_tag, tags); |
4bb659b1 JA |
264 | if (tag != -1) |
265 | return tag; | |
266 | ||
cb96a42c | 267 | if (!(data->gfp & __GFP_WAIT)) |
4bb659b1 JA |
268 | return -1; |
269 | ||
35d37c66 | 270 | bs = bt_wait_ptr(bt, hctx); |
4bb659b1 | 271 | do { |
4bb659b1 JA |
272 | prepare_to_wait(&bs->wait, &wait, TASK_UNINTERRUPTIBLE); |
273 | ||
24391c0d | 274 | tag = __bt_get(hctx, bt, last_tag, tags); |
4bb659b1 JA |
275 | if (tag != -1) |
276 | break; | |
277 | ||
b3223207 BVA |
278 | /* |
279 | * We're out of tags on this hardware queue, kick any | |
280 | * pending IO submits before going to sleep waiting for | |
281 | * some to complete. | |
282 | */ | |
283 | blk_mq_run_hw_queue(hctx, false); | |
284 | ||
080ff351 JA |
285 | /* |
286 | * Retry tag allocation after running the hardware queue, | |
287 | * as running the queue may also have found completions. | |
288 | */ | |
24391c0d | 289 | tag = __bt_get(hctx, bt, last_tag, tags); |
080ff351 JA |
290 | if (tag != -1) |
291 | break; | |
292 | ||
cb96a42c ML |
293 | blk_mq_put_ctx(data->ctx); |
294 | ||
4bb659b1 | 295 | io_schedule(); |
cb96a42c ML |
296 | |
297 | data->ctx = blk_mq_get_ctx(data->q); | |
298 | data->hctx = data->q->mq_ops->map_queue(data->q, | |
299 | data->ctx->cpu); | |
300 | if (data->reserved) { | |
301 | bt = &data->hctx->tags->breserved_tags; | |
302 | } else { | |
303 | last_tag = &data->ctx->last_tag; | |
304 | hctx = data->hctx; | |
305 | bt = &hctx->tags->bitmap_tags; | |
306 | } | |
35d37c66 JA |
307 | finish_wait(&bs->wait, &wait); |
308 | bs = bt_wait_ptr(bt, hctx); | |
4bb659b1 JA |
309 | } while (1); |
310 | ||
311 | finish_wait(&bs->wait, &wait); | |
312 | return tag; | |
313 | } | |
314 | ||
cb96a42c | 315 | static unsigned int __blk_mq_get_tag(struct blk_mq_alloc_data *data) |
4bb659b1 JA |
316 | { |
317 | int tag; | |
318 | ||
cb96a42c | 319 | tag = bt_get(data, &data->hctx->tags->bitmap_tags, data->hctx, |
24391c0d | 320 | &data->ctx->last_tag, data->hctx->tags); |
4bb659b1 | 321 | if (tag >= 0) |
cb96a42c | 322 | return tag + data->hctx->tags->nr_reserved_tags; |
4bb659b1 JA |
323 | |
324 | return BLK_MQ_TAG_FAIL; | |
320ae51f JA |
325 | } |
326 | ||
cb96a42c | 327 | static unsigned int __blk_mq_get_reserved_tag(struct blk_mq_alloc_data *data) |
320ae51f | 328 | { |
4bb659b1 | 329 | int tag, zero = 0; |
320ae51f | 330 | |
cb96a42c | 331 | if (unlikely(!data->hctx->tags->nr_reserved_tags)) { |
320ae51f JA |
332 | WARN_ON_ONCE(1); |
333 | return BLK_MQ_TAG_FAIL; | |
334 | } | |
335 | ||
24391c0d SL |
336 | tag = bt_get(data, &data->hctx->tags->breserved_tags, NULL, &zero, |
337 | data->hctx->tags); | |
320ae51f JA |
338 | if (tag < 0) |
339 | return BLK_MQ_TAG_FAIL; | |
4bb659b1 | 340 | |
320ae51f JA |
341 | return tag; |
342 | } | |
343 | ||
cb96a42c | 344 | unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data) |
320ae51f | 345 | { |
cb96a42c ML |
346 | if (!data->reserved) |
347 | return __blk_mq_get_tag(data); | |
320ae51f | 348 | |
cb96a42c | 349 | return __blk_mq_get_reserved_tag(data); |
320ae51f JA |
350 | } |
351 | ||
4bb659b1 JA |
352 | static struct bt_wait_state *bt_wake_ptr(struct blk_mq_bitmap_tags *bt) |
353 | { | |
354 | int i, wake_index; | |
355 | ||
8537b120 | 356 | wake_index = atomic_read(&bt->wake_index); |
4bb659b1 JA |
357 | for (i = 0; i < BT_WAIT_QUEUES; i++) { |
358 | struct bt_wait_state *bs = &bt->bs[wake_index]; | |
359 | ||
360 | if (waitqueue_active(&bs->wait)) { | |
8537b120 AG |
361 | int o = atomic_read(&bt->wake_index); |
362 | if (wake_index != o) | |
363 | atomic_cmpxchg(&bt->wake_index, o, wake_index); | |
4bb659b1 JA |
364 | |
365 | return bs; | |
366 | } | |
367 | ||
8537b120 | 368 | wake_index = bt_index_inc(wake_index); |
4bb659b1 JA |
369 | } |
370 | ||
371 | return NULL; | |
372 | } | |
373 | ||
374 | static void bt_clear_tag(struct blk_mq_bitmap_tags *bt, unsigned int tag) | |
375 | { | |
59d13bf5 | 376 | const int index = TAG_TO_INDEX(bt, tag); |
4bb659b1 | 377 | struct bt_wait_state *bs; |
2971c35f | 378 | int wait_cnt; |
4bb659b1 | 379 | |
c38d185d BVA |
380 | clear_bit(TAG_TO_BIT(bt, tag), &bt->map[index].word); |
381 | ||
382 | /* Ensure that the wait list checks occur after clear_bit(). */ | |
383 | smp_mb(); | |
4bb659b1 JA |
384 | |
385 | bs = bt_wake_ptr(bt); | |
2971c35f AG |
386 | if (!bs) |
387 | return; | |
388 | ||
389 | wait_cnt = atomic_dec_return(&bs->wait_cnt); | |
9d8f0bcc BVA |
390 | if (unlikely(wait_cnt < 0)) |
391 | wait_cnt = atomic_inc_return(&bs->wait_cnt); | |
2971c35f | 392 | if (wait_cnt == 0) { |
2971c35f | 393 | atomic_add(bt->wake_cnt, &bs->wait_cnt); |
8537b120 | 394 | bt_index_atomic_inc(&bt->wake_index); |
4bb659b1 JA |
395 | wake_up(&bs->wait); |
396 | } | |
397 | } | |
398 | ||
0d2602ca | 399 | void blk_mq_put_tag(struct blk_mq_hw_ctx *hctx, unsigned int tag, |
4bb659b1 | 400 | unsigned int *last_tag) |
320ae51f | 401 | { |
0d2602ca JA |
402 | struct blk_mq_tags *tags = hctx->tags; |
403 | ||
4bb659b1 JA |
404 | if (tag >= tags->nr_reserved_tags) { |
405 | const int real_tag = tag - tags->nr_reserved_tags; | |
406 | ||
70114c39 JA |
407 | BUG_ON(real_tag >= tags->nr_tags); |
408 | bt_clear_tag(&tags->bitmap_tags, real_tag); | |
24391c0d SL |
409 | if (likely(tags->alloc_policy == BLK_TAG_ALLOC_FIFO)) |
410 | *last_tag = real_tag; | |
70114c39 JA |
411 | } else { |
412 | BUG_ON(tag >= tags->nr_reserved_tags); | |
413 | bt_clear_tag(&tags->breserved_tags, tag); | |
414 | } | |
320ae51f JA |
415 | } |
416 | ||
81481eb4 CH |
417 | static void bt_for_each(struct blk_mq_hw_ctx *hctx, |
418 | struct blk_mq_bitmap_tags *bt, unsigned int off, | |
419 | busy_iter_fn *fn, void *data, bool reserved) | |
320ae51f | 420 | { |
81481eb4 CH |
421 | struct request *rq; |
422 | int bit, i; | |
4bb659b1 JA |
423 | |
424 | for (i = 0; i < bt->map_nr; i++) { | |
e93ecf60 | 425 | struct blk_align_bitmap *bm = &bt->map[i]; |
4bb659b1 | 426 | |
81481eb4 CH |
427 | for (bit = find_first_bit(&bm->word, bm->depth); |
428 | bit < bm->depth; | |
429 | bit = find_next_bit(&bm->word, bm->depth, bit + 1)) { | |
430 | rq = blk_mq_tag_to_rq(hctx->tags, off + bit); | |
431 | if (rq->q == hctx->queue) | |
432 | fn(hctx, rq, data, reserved); | |
433 | } | |
4bb659b1 | 434 | |
59d13bf5 | 435 | off += (1 << bt->bits_per_word); |
4bb659b1 | 436 | } |
320ae51f JA |
437 | } |
438 | ||
81481eb4 CH |
439 | void blk_mq_tag_busy_iter(struct blk_mq_hw_ctx *hctx, busy_iter_fn *fn, |
440 | void *priv) | |
320ae51f | 441 | { |
81481eb4 | 442 | struct blk_mq_tags *tags = hctx->tags; |
320ae51f | 443 | |
320ae51f | 444 | if (tags->nr_reserved_tags) |
81481eb4 CH |
445 | bt_for_each(hctx, &tags->breserved_tags, 0, fn, priv, true); |
446 | bt_for_each(hctx, &tags->bitmap_tags, tags->nr_reserved_tags, fn, priv, | |
447 | false); | |
320ae51f | 448 | } |
edf866b3 | 449 | EXPORT_SYMBOL(blk_mq_tag_busy_iter); |
320ae51f | 450 | |
4bb659b1 JA |
451 | static unsigned int bt_unused_tags(struct blk_mq_bitmap_tags *bt) |
452 | { | |
453 | unsigned int i, used; | |
454 | ||
455 | for (i = 0, used = 0; i < bt->map_nr; i++) { | |
e93ecf60 | 456 | struct blk_align_bitmap *bm = &bt->map[i]; |
4bb659b1 JA |
457 | |
458 | used += bitmap_weight(&bm->word, bm->depth); | |
459 | } | |
460 | ||
461 | return bt->depth - used; | |
462 | } | |
463 | ||
e3a2b3f9 JA |
464 | static void bt_update_count(struct blk_mq_bitmap_tags *bt, |
465 | unsigned int depth) | |
466 | { | |
467 | unsigned int tags_per_word = 1U << bt->bits_per_word; | |
468 | unsigned int map_depth = depth; | |
469 | ||
470 | if (depth) { | |
471 | int i; | |
472 | ||
473 | for (i = 0; i < bt->map_nr; i++) { | |
474 | bt->map[i].depth = min(map_depth, tags_per_word); | |
475 | map_depth -= bt->map[i].depth; | |
476 | } | |
477 | } | |
478 | ||
479 | bt->wake_cnt = BT_WAIT_BATCH; | |
abab13b5 JA |
480 | if (bt->wake_cnt > depth / BT_WAIT_QUEUES) |
481 | bt->wake_cnt = max(1U, depth / BT_WAIT_QUEUES); | |
e3a2b3f9 JA |
482 | |
483 | bt->depth = depth; | |
484 | } | |
485 | ||
4bb659b1 JA |
486 | static int bt_alloc(struct blk_mq_bitmap_tags *bt, unsigned int depth, |
487 | int node, bool reserved) | |
488 | { | |
489 | int i; | |
490 | ||
59d13bf5 JA |
491 | bt->bits_per_word = ilog2(BITS_PER_LONG); |
492 | ||
4bb659b1 JA |
493 | /* |
494 | * Depth can be zero for reserved tags, that's not a failure | |
495 | * condition. | |
496 | */ | |
497 | if (depth) { | |
e3a2b3f9 | 498 | unsigned int nr, tags_per_word; |
59d13bf5 JA |
499 | |
500 | tags_per_word = (1 << bt->bits_per_word); | |
501 | ||
502 | /* | |
503 | * If the tag space is small, shrink the number of tags | |
504 | * per word so we spread over a few cachelines, at least. | |
505 | * If less than 4 tags, just forget about it, it's not | |
506 | * going to work optimally anyway. | |
507 | */ | |
508 | if (depth >= 4) { | |
509 | while (tags_per_word * 4 > depth) { | |
510 | bt->bits_per_word--; | |
511 | tags_per_word = (1 << bt->bits_per_word); | |
512 | } | |
513 | } | |
4bb659b1 | 514 | |
59d13bf5 | 515 | nr = ALIGN(depth, tags_per_word) / tags_per_word; |
e93ecf60 | 516 | bt->map = kzalloc_node(nr * sizeof(struct blk_align_bitmap), |
4bb659b1 JA |
517 | GFP_KERNEL, node); |
518 | if (!bt->map) | |
519 | return -ENOMEM; | |
520 | ||
521 | bt->map_nr = nr; | |
4bb659b1 JA |
522 | } |
523 | ||
524 | bt->bs = kzalloc(BT_WAIT_QUEUES * sizeof(*bt->bs), GFP_KERNEL); | |
525 | if (!bt->bs) { | |
526 | kfree(bt->map); | |
564e559f | 527 | bt->map = NULL; |
4bb659b1 JA |
528 | return -ENOMEM; |
529 | } | |
530 | ||
86fb5c56 AG |
531 | bt_update_count(bt, depth); |
532 | ||
533 | for (i = 0; i < BT_WAIT_QUEUES; i++) { | |
4bb659b1 | 534 | init_waitqueue_head(&bt->bs[i].wait); |
86fb5c56 AG |
535 | atomic_set(&bt->bs[i].wait_cnt, bt->wake_cnt); |
536 | } | |
4bb659b1 | 537 | |
4bb659b1 JA |
538 | return 0; |
539 | } | |
540 | ||
541 | static void bt_free(struct blk_mq_bitmap_tags *bt) | |
542 | { | |
543 | kfree(bt->map); | |
544 | kfree(bt->bs); | |
545 | } | |
546 | ||
547 | static struct blk_mq_tags *blk_mq_init_bitmap_tags(struct blk_mq_tags *tags, | |
24391c0d | 548 | int node, int alloc_policy) |
4bb659b1 JA |
549 | { |
550 | unsigned int depth = tags->nr_tags - tags->nr_reserved_tags; | |
551 | ||
24391c0d SL |
552 | tags->alloc_policy = alloc_policy; |
553 | ||
4bb659b1 JA |
554 | if (bt_alloc(&tags->bitmap_tags, depth, node, false)) |
555 | goto enomem; | |
556 | if (bt_alloc(&tags->breserved_tags, tags->nr_reserved_tags, node, true)) | |
557 | goto enomem; | |
558 | ||
559 | return tags; | |
560 | enomem: | |
561 | bt_free(&tags->bitmap_tags); | |
562 | kfree(tags); | |
563 | return NULL; | |
564 | } | |
565 | ||
320ae51f | 566 | struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags, |
24391c0d SL |
567 | unsigned int reserved_tags, |
568 | int node, int alloc_policy) | |
320ae51f | 569 | { |
320ae51f | 570 | struct blk_mq_tags *tags; |
320ae51f JA |
571 | |
572 | if (total_tags > BLK_MQ_TAG_MAX) { | |
573 | pr_err("blk-mq: tag depth too large\n"); | |
574 | return NULL; | |
575 | } | |
576 | ||
577 | tags = kzalloc_node(sizeof(*tags), GFP_KERNEL, node); | |
578 | if (!tags) | |
579 | return NULL; | |
580 | ||
320ae51f JA |
581 | tags->nr_tags = total_tags; |
582 | tags->nr_reserved_tags = reserved_tags; | |
320ae51f | 583 | |
24391c0d | 584 | return blk_mq_init_bitmap_tags(tags, node, alloc_policy); |
320ae51f JA |
585 | } |
586 | ||
587 | void blk_mq_free_tags(struct blk_mq_tags *tags) | |
588 | { | |
4bb659b1 JA |
589 | bt_free(&tags->bitmap_tags); |
590 | bt_free(&tags->breserved_tags); | |
320ae51f JA |
591 | kfree(tags); |
592 | } | |
593 | ||
4bb659b1 JA |
594 | void blk_mq_tag_init_last_tag(struct blk_mq_tags *tags, unsigned int *tag) |
595 | { | |
596 | unsigned int depth = tags->nr_tags - tags->nr_reserved_tags; | |
597 | ||
9d3d21ae | 598 | *tag = prandom_u32() % depth; |
4bb659b1 JA |
599 | } |
600 | ||
e3a2b3f9 JA |
601 | int blk_mq_tag_update_depth(struct blk_mq_tags *tags, unsigned int tdepth) |
602 | { | |
603 | tdepth -= tags->nr_reserved_tags; | |
604 | if (tdepth > tags->nr_tags) | |
605 | return -EINVAL; | |
606 | ||
607 | /* | |
608 | * Don't need (or can't) update reserved tags here, they remain | |
609 | * static and should never need resizing. | |
610 | */ | |
611 | bt_update_count(&tags->bitmap_tags, tdepth); | |
aed3ea94 | 612 | blk_mq_tag_wakeup_all(tags, false); |
e3a2b3f9 JA |
613 | return 0; |
614 | } | |
615 | ||
205fb5f5 BVA |
616 | /** |
617 | * blk_mq_unique_tag() - return a tag that is unique queue-wide | |
618 | * @rq: request for which to compute a unique tag | |
619 | * | |
620 | * The tag field in struct request is unique per hardware queue but not over | |
621 | * all hardware queues. Hence this function that returns a tag with the | |
622 | * hardware context index in the upper bits and the per hardware queue tag in | |
623 | * the lower bits. | |
624 | * | |
625 | * Note: When called for a request that is queued on a non-multiqueue request | |
626 | * queue, the hardware context index is set to zero. | |
627 | */ | |
628 | u32 blk_mq_unique_tag(struct request *rq) | |
629 | { | |
630 | struct request_queue *q = rq->q; | |
631 | struct blk_mq_hw_ctx *hctx; | |
632 | int hwq = 0; | |
633 | ||
634 | if (q->mq_ops) { | |
635 | hctx = q->mq_ops->map_queue(q, rq->mq_ctx->cpu); | |
636 | hwq = hctx->queue_num; | |
637 | } | |
638 | ||
639 | return (hwq << BLK_MQ_UNIQUE_TAG_BITS) | | |
640 | (rq->tag & BLK_MQ_UNIQUE_TAG_MASK); | |
641 | } | |
642 | EXPORT_SYMBOL(blk_mq_unique_tag); | |
643 | ||
320ae51f JA |
644 | ssize_t blk_mq_tag_sysfs_show(struct blk_mq_tags *tags, char *page) |
645 | { | |
646 | char *orig_page = page; | |
4bb659b1 | 647 | unsigned int free, res; |
320ae51f JA |
648 | |
649 | if (!tags) | |
650 | return 0; | |
651 | ||
59d13bf5 JA |
652 | page += sprintf(page, "nr_tags=%u, reserved_tags=%u, " |
653 | "bits_per_word=%u\n", | |
654 | tags->nr_tags, tags->nr_reserved_tags, | |
655 | tags->bitmap_tags.bits_per_word); | |
320ae51f | 656 | |
4bb659b1 JA |
657 | free = bt_unused_tags(&tags->bitmap_tags); |
658 | res = bt_unused_tags(&tags->breserved_tags); | |
320ae51f | 659 | |
4bb659b1 | 660 | page += sprintf(page, "nr_free=%u, nr_reserved=%u\n", free, res); |
0d2602ca | 661 | page += sprintf(page, "active_queues=%u\n", atomic_read(&tags->active_queues)); |
320ae51f JA |
662 | |
663 | return page - orig_page; | |
664 | } |