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cafe5635 KO |
1 | /* |
2 | * Main bcache entry point - handle a read or a write request and decide what to | |
3 | * do with it; the make_request functions are called by the block layer. | |
4 | * | |
5 | * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com> | |
6 | * Copyright 2012 Google, Inc. | |
7 | */ | |
8 | ||
9 | #include "bcache.h" | |
10 | #include "btree.h" | |
11 | #include "debug.h" | |
12 | #include "request.h" | |
13 | ||
14 | #include <linux/cgroup.h> | |
15 | #include <linux/module.h> | |
16 | #include <linux/hash.h> | |
17 | #include <linux/random.h> | |
18 | #include "blk-cgroup.h" | |
19 | ||
20 | #include <trace/events/bcache.h> | |
21 | ||
22 | #define CUTOFF_CACHE_ADD 95 | |
23 | #define CUTOFF_CACHE_READA 90 | |
24 | #define CUTOFF_WRITEBACK 50 | |
25 | #define CUTOFF_WRITEBACK_SYNC 75 | |
26 | ||
27 | struct kmem_cache *bch_search_cache; | |
28 | ||
29 | static void check_should_skip(struct cached_dev *, struct search *); | |
30 | ||
31 | /* Cgroup interface */ | |
32 | ||
33 | #ifdef CONFIG_CGROUP_BCACHE | |
34 | static struct bch_cgroup bcache_default_cgroup = { .cache_mode = -1 }; | |
35 | ||
36 | static struct bch_cgroup *cgroup_to_bcache(struct cgroup *cgroup) | |
37 | { | |
38 | struct cgroup_subsys_state *css; | |
39 | return cgroup && | |
40 | (css = cgroup_subsys_state(cgroup, bcache_subsys_id)) | |
41 | ? container_of(css, struct bch_cgroup, css) | |
42 | : &bcache_default_cgroup; | |
43 | } | |
44 | ||
45 | struct bch_cgroup *bch_bio_to_cgroup(struct bio *bio) | |
46 | { | |
47 | struct cgroup_subsys_state *css = bio->bi_css | |
48 | ? cgroup_subsys_state(bio->bi_css->cgroup, bcache_subsys_id) | |
49 | : task_subsys_state(current, bcache_subsys_id); | |
50 | ||
51 | return css | |
52 | ? container_of(css, struct bch_cgroup, css) | |
53 | : &bcache_default_cgroup; | |
54 | } | |
55 | ||
56 | static ssize_t cache_mode_read(struct cgroup *cgrp, struct cftype *cft, | |
57 | struct file *file, | |
58 | char __user *buf, size_t nbytes, loff_t *ppos) | |
59 | { | |
60 | char tmp[1024]; | |
169ef1cf KO |
61 | int len = bch_snprint_string_list(tmp, PAGE_SIZE, bch_cache_modes, |
62 | cgroup_to_bcache(cgrp)->cache_mode + 1); | |
cafe5635 KO |
63 | |
64 | if (len < 0) | |
65 | return len; | |
66 | ||
67 | return simple_read_from_buffer(buf, nbytes, ppos, tmp, len); | |
68 | } | |
69 | ||
70 | static int cache_mode_write(struct cgroup *cgrp, struct cftype *cft, | |
71 | const char *buf) | |
72 | { | |
169ef1cf | 73 | int v = bch_read_string_list(buf, bch_cache_modes); |
cafe5635 KO |
74 | if (v < 0) |
75 | return v; | |
76 | ||
77 | cgroup_to_bcache(cgrp)->cache_mode = v - 1; | |
78 | return 0; | |
79 | } | |
80 | ||
81 | static u64 bch_verify_read(struct cgroup *cgrp, struct cftype *cft) | |
82 | { | |
83 | return cgroup_to_bcache(cgrp)->verify; | |
84 | } | |
85 | ||
86 | static int bch_verify_write(struct cgroup *cgrp, struct cftype *cft, u64 val) | |
87 | { | |
88 | cgroup_to_bcache(cgrp)->verify = val; | |
89 | return 0; | |
90 | } | |
91 | ||
92 | static u64 bch_cache_hits_read(struct cgroup *cgrp, struct cftype *cft) | |
93 | { | |
94 | struct bch_cgroup *bcachecg = cgroup_to_bcache(cgrp); | |
95 | return atomic_read(&bcachecg->stats.cache_hits); | |
96 | } | |
97 | ||
98 | static u64 bch_cache_misses_read(struct cgroup *cgrp, struct cftype *cft) | |
99 | { | |
100 | struct bch_cgroup *bcachecg = cgroup_to_bcache(cgrp); | |
101 | return atomic_read(&bcachecg->stats.cache_misses); | |
102 | } | |
103 | ||
104 | static u64 bch_cache_bypass_hits_read(struct cgroup *cgrp, | |
105 | struct cftype *cft) | |
106 | { | |
107 | struct bch_cgroup *bcachecg = cgroup_to_bcache(cgrp); | |
108 | return atomic_read(&bcachecg->stats.cache_bypass_hits); | |
109 | } | |
110 | ||
111 | static u64 bch_cache_bypass_misses_read(struct cgroup *cgrp, | |
112 | struct cftype *cft) | |
113 | { | |
114 | struct bch_cgroup *bcachecg = cgroup_to_bcache(cgrp); | |
115 | return atomic_read(&bcachecg->stats.cache_bypass_misses); | |
116 | } | |
117 | ||
118 | static struct cftype bch_files[] = { | |
119 | { | |
120 | .name = "cache_mode", | |
121 | .read = cache_mode_read, | |
122 | .write_string = cache_mode_write, | |
123 | }, | |
124 | { | |
125 | .name = "verify", | |
126 | .read_u64 = bch_verify_read, | |
127 | .write_u64 = bch_verify_write, | |
128 | }, | |
129 | { | |
130 | .name = "cache_hits", | |
131 | .read_u64 = bch_cache_hits_read, | |
132 | }, | |
133 | { | |
134 | .name = "cache_misses", | |
135 | .read_u64 = bch_cache_misses_read, | |
136 | }, | |
137 | { | |
138 | .name = "cache_bypass_hits", | |
139 | .read_u64 = bch_cache_bypass_hits_read, | |
140 | }, | |
141 | { | |
142 | .name = "cache_bypass_misses", | |
143 | .read_u64 = bch_cache_bypass_misses_read, | |
144 | }, | |
145 | { } /* terminate */ | |
146 | }; | |
147 | ||
148 | static void init_bch_cgroup(struct bch_cgroup *cg) | |
149 | { | |
150 | cg->cache_mode = -1; | |
151 | } | |
152 | ||
153 | static struct cgroup_subsys_state *bcachecg_create(struct cgroup *cgroup) | |
154 | { | |
155 | struct bch_cgroup *cg; | |
156 | ||
157 | cg = kzalloc(sizeof(*cg), GFP_KERNEL); | |
158 | if (!cg) | |
159 | return ERR_PTR(-ENOMEM); | |
160 | init_bch_cgroup(cg); | |
161 | return &cg->css; | |
162 | } | |
163 | ||
164 | static void bcachecg_destroy(struct cgroup *cgroup) | |
165 | { | |
166 | struct bch_cgroup *cg = cgroup_to_bcache(cgroup); | |
167 | free_css_id(&bcache_subsys, &cg->css); | |
168 | kfree(cg); | |
169 | } | |
170 | ||
171 | struct cgroup_subsys bcache_subsys = { | |
172 | .create = bcachecg_create, | |
173 | .destroy = bcachecg_destroy, | |
174 | .subsys_id = bcache_subsys_id, | |
175 | .name = "bcache", | |
176 | .module = THIS_MODULE, | |
177 | }; | |
178 | EXPORT_SYMBOL_GPL(bcache_subsys); | |
179 | #endif | |
180 | ||
181 | static unsigned cache_mode(struct cached_dev *dc, struct bio *bio) | |
182 | { | |
183 | #ifdef CONFIG_CGROUP_BCACHE | |
184 | int r = bch_bio_to_cgroup(bio)->cache_mode; | |
185 | if (r >= 0) | |
186 | return r; | |
187 | #endif | |
188 | return BDEV_CACHE_MODE(&dc->sb); | |
189 | } | |
190 | ||
191 | static bool verify(struct cached_dev *dc, struct bio *bio) | |
192 | { | |
193 | #ifdef CONFIG_CGROUP_BCACHE | |
194 | if (bch_bio_to_cgroup(bio)->verify) | |
195 | return true; | |
196 | #endif | |
197 | return dc->verify; | |
198 | } | |
199 | ||
200 | static void bio_csum(struct bio *bio, struct bkey *k) | |
201 | { | |
202 | struct bio_vec *bv; | |
203 | uint64_t csum = 0; | |
204 | int i; | |
205 | ||
206 | bio_for_each_segment(bv, bio, i) { | |
207 | void *d = kmap(bv->bv_page) + bv->bv_offset; | |
169ef1cf | 208 | csum = bch_crc64_update(csum, d, bv->bv_len); |
cafe5635 KO |
209 | kunmap(bv->bv_page); |
210 | } | |
211 | ||
212 | k->ptr[KEY_PTRS(k)] = csum & (~0ULL >> 1); | |
213 | } | |
214 | ||
215 | /* Insert data into cache */ | |
216 | ||
217 | static void bio_invalidate(struct closure *cl) | |
218 | { | |
219 | struct btree_op *op = container_of(cl, struct btree_op, cl); | |
220 | struct bio *bio = op->cache_bio; | |
221 | ||
222 | pr_debug("invalidating %i sectors from %llu", | |
223 | bio_sectors(bio), (uint64_t) bio->bi_sector); | |
224 | ||
225 | while (bio_sectors(bio)) { | |
226 | unsigned len = min(bio_sectors(bio), 1U << 14); | |
227 | ||
228 | if (bch_keylist_realloc(&op->keys, 0, op->c)) | |
229 | goto out; | |
230 | ||
231 | bio->bi_sector += len; | |
232 | bio->bi_size -= len << 9; | |
233 | ||
234 | bch_keylist_add(&op->keys, | |
235 | &KEY(op->inode, bio->bi_sector, len)); | |
236 | } | |
237 | ||
238 | op->insert_data_done = true; | |
239 | bio_put(bio); | |
240 | out: | |
241 | continue_at(cl, bch_journal, bcache_wq); | |
242 | } | |
243 | ||
244 | struct open_bucket { | |
245 | struct list_head list; | |
246 | struct task_struct *last; | |
247 | unsigned sectors_free; | |
248 | BKEY_PADDED(key); | |
249 | }; | |
250 | ||
251 | void bch_open_buckets_free(struct cache_set *c) | |
252 | { | |
253 | struct open_bucket *b; | |
254 | ||
255 | while (!list_empty(&c->data_buckets)) { | |
256 | b = list_first_entry(&c->data_buckets, | |
257 | struct open_bucket, list); | |
258 | list_del(&b->list); | |
259 | kfree(b); | |
260 | } | |
261 | } | |
262 | ||
263 | int bch_open_buckets_alloc(struct cache_set *c) | |
264 | { | |
265 | int i; | |
266 | ||
267 | spin_lock_init(&c->data_bucket_lock); | |
268 | ||
269 | for (i = 0; i < 6; i++) { | |
270 | struct open_bucket *b = kzalloc(sizeof(*b), GFP_KERNEL); | |
271 | if (!b) | |
272 | return -ENOMEM; | |
273 | ||
274 | list_add(&b->list, &c->data_buckets); | |
275 | } | |
276 | ||
277 | return 0; | |
278 | } | |
279 | ||
280 | /* | |
281 | * We keep multiple buckets open for writes, and try to segregate different | |
282 | * write streams for better cache utilization: first we look for a bucket where | |
283 | * the last write to it was sequential with the current write, and failing that | |
284 | * we look for a bucket that was last used by the same task. | |
285 | * | |
286 | * The ideas is if you've got multiple tasks pulling data into the cache at the | |
287 | * same time, you'll get better cache utilization if you try to segregate their | |
288 | * data and preserve locality. | |
289 | * | |
290 | * For example, say you've starting Firefox at the same time you're copying a | |
291 | * bunch of files. Firefox will likely end up being fairly hot and stay in the | |
292 | * cache awhile, but the data you copied might not be; if you wrote all that | |
293 | * data to the same buckets it'd get invalidated at the same time. | |
294 | * | |
295 | * Both of those tasks will be doing fairly random IO so we can't rely on | |
296 | * detecting sequential IO to segregate their data, but going off of the task | |
297 | * should be a sane heuristic. | |
298 | */ | |
299 | static struct open_bucket *pick_data_bucket(struct cache_set *c, | |
300 | const struct bkey *search, | |
301 | struct task_struct *task, | |
302 | struct bkey *alloc) | |
303 | { | |
304 | struct open_bucket *ret, *ret_task = NULL; | |
305 | ||
306 | list_for_each_entry_reverse(ret, &c->data_buckets, list) | |
307 | if (!bkey_cmp(&ret->key, search)) | |
308 | goto found; | |
309 | else if (ret->last == task) | |
310 | ret_task = ret; | |
311 | ||
312 | ret = ret_task ?: list_first_entry(&c->data_buckets, | |
313 | struct open_bucket, list); | |
314 | found: | |
315 | if (!ret->sectors_free && KEY_PTRS(alloc)) { | |
316 | ret->sectors_free = c->sb.bucket_size; | |
317 | bkey_copy(&ret->key, alloc); | |
318 | bkey_init(alloc); | |
319 | } | |
320 | ||
321 | if (!ret->sectors_free) | |
322 | ret = NULL; | |
323 | ||
324 | return ret; | |
325 | } | |
326 | ||
327 | /* | |
328 | * Allocates some space in the cache to write to, and k to point to the newly | |
329 | * allocated space, and updates KEY_SIZE(k) and KEY_OFFSET(k) (to point to the | |
330 | * end of the newly allocated space). | |
331 | * | |
332 | * May allocate fewer sectors than @sectors, KEY_SIZE(k) indicates how many | |
333 | * sectors were actually allocated. | |
334 | * | |
335 | * If s->writeback is true, will not fail. | |
336 | */ | |
337 | static bool bch_alloc_sectors(struct bkey *k, unsigned sectors, | |
338 | struct search *s) | |
339 | { | |
340 | struct cache_set *c = s->op.c; | |
341 | struct open_bucket *b; | |
342 | BKEY_PADDED(key) alloc; | |
343 | struct closure cl, *w = NULL; | |
344 | unsigned i; | |
345 | ||
346 | if (s->writeback) { | |
347 | closure_init_stack(&cl); | |
348 | w = &cl; | |
349 | } | |
350 | ||
351 | /* | |
352 | * We might have to allocate a new bucket, which we can't do with a | |
353 | * spinlock held. So if we have to allocate, we drop the lock, allocate | |
354 | * and then retry. KEY_PTRS() indicates whether alloc points to | |
355 | * allocated bucket(s). | |
356 | */ | |
357 | ||
358 | bkey_init(&alloc.key); | |
359 | spin_lock(&c->data_bucket_lock); | |
360 | ||
361 | while (!(b = pick_data_bucket(c, k, s->task, &alloc.key))) { | |
362 | unsigned watermark = s->op.write_prio | |
363 | ? WATERMARK_MOVINGGC | |
364 | : WATERMARK_NONE; | |
365 | ||
366 | spin_unlock(&c->data_bucket_lock); | |
367 | ||
368 | if (bch_bucket_alloc_set(c, watermark, &alloc.key, 1, w)) | |
369 | return false; | |
370 | ||
371 | spin_lock(&c->data_bucket_lock); | |
372 | } | |
373 | ||
374 | /* | |
375 | * If we had to allocate, we might race and not need to allocate the | |
376 | * second time we call find_data_bucket(). If we allocated a bucket but | |
377 | * didn't use it, drop the refcount bch_bucket_alloc_set() took: | |
378 | */ | |
379 | if (KEY_PTRS(&alloc.key)) | |
380 | __bkey_put(c, &alloc.key); | |
381 | ||
382 | for (i = 0; i < KEY_PTRS(&b->key); i++) | |
383 | EBUG_ON(ptr_stale(c, &b->key, i)); | |
384 | ||
385 | /* Set up the pointer to the space we're allocating: */ | |
386 | ||
387 | for (i = 0; i < KEY_PTRS(&b->key); i++) | |
388 | k->ptr[i] = b->key.ptr[i]; | |
389 | ||
390 | sectors = min(sectors, b->sectors_free); | |
391 | ||
392 | SET_KEY_OFFSET(k, KEY_OFFSET(k) + sectors); | |
393 | SET_KEY_SIZE(k, sectors); | |
394 | SET_KEY_PTRS(k, KEY_PTRS(&b->key)); | |
395 | ||
396 | /* | |
397 | * Move b to the end of the lru, and keep track of what this bucket was | |
398 | * last used for: | |
399 | */ | |
400 | list_move_tail(&b->list, &c->data_buckets); | |
401 | bkey_copy_key(&b->key, k); | |
402 | b->last = s->task; | |
403 | ||
404 | b->sectors_free -= sectors; | |
405 | ||
406 | for (i = 0; i < KEY_PTRS(&b->key); i++) { | |
407 | SET_PTR_OFFSET(&b->key, i, PTR_OFFSET(&b->key, i) + sectors); | |
408 | ||
409 | atomic_long_add(sectors, | |
410 | &PTR_CACHE(c, &b->key, i)->sectors_written); | |
411 | } | |
412 | ||
413 | if (b->sectors_free < c->sb.block_size) | |
414 | b->sectors_free = 0; | |
415 | ||
416 | /* | |
417 | * k takes refcounts on the buckets it points to until it's inserted | |
418 | * into the btree, but if we're done with this bucket we just transfer | |
419 | * get_data_bucket()'s refcount. | |
420 | */ | |
421 | if (b->sectors_free) | |
422 | for (i = 0; i < KEY_PTRS(&b->key); i++) | |
423 | atomic_inc(&PTR_BUCKET(c, &b->key, i)->pin); | |
424 | ||
425 | spin_unlock(&c->data_bucket_lock); | |
426 | return true; | |
427 | } | |
428 | ||
429 | static void bch_insert_data_error(struct closure *cl) | |
430 | { | |
431 | struct btree_op *op = container_of(cl, struct btree_op, cl); | |
432 | ||
433 | /* | |
434 | * Our data write just errored, which means we've got a bunch of keys to | |
435 | * insert that point to data that wasn't succesfully written. | |
436 | * | |
437 | * We don't have to insert those keys but we still have to invalidate | |
438 | * that region of the cache - so, if we just strip off all the pointers | |
439 | * from the keys we'll accomplish just that. | |
440 | */ | |
441 | ||
442 | struct bkey *src = op->keys.bottom, *dst = op->keys.bottom; | |
443 | ||
444 | while (src != op->keys.top) { | |
445 | struct bkey *n = bkey_next(src); | |
446 | ||
447 | SET_KEY_PTRS(src, 0); | |
448 | bkey_copy(dst, src); | |
449 | ||
450 | dst = bkey_next(dst); | |
451 | src = n; | |
452 | } | |
453 | ||
454 | op->keys.top = dst; | |
455 | ||
456 | bch_journal(cl); | |
457 | } | |
458 | ||
459 | static void bch_insert_data_endio(struct bio *bio, int error) | |
460 | { | |
461 | struct closure *cl = bio->bi_private; | |
462 | struct btree_op *op = container_of(cl, struct btree_op, cl); | |
463 | struct search *s = container_of(op, struct search, op); | |
464 | ||
465 | if (error) { | |
466 | /* TODO: We could try to recover from this. */ | |
467 | if (s->writeback) | |
468 | s->error = error; | |
469 | else if (s->write) | |
470 | set_closure_fn(cl, bch_insert_data_error, bcache_wq); | |
471 | else | |
472 | set_closure_fn(cl, NULL, NULL); | |
473 | } | |
474 | ||
475 | bch_bbio_endio(op->c, bio, error, "writing data to cache"); | |
476 | } | |
477 | ||
478 | static void bch_insert_data_loop(struct closure *cl) | |
479 | { | |
480 | struct btree_op *op = container_of(cl, struct btree_op, cl); | |
481 | struct search *s = container_of(op, struct search, op); | |
482 | struct bio *bio = op->cache_bio, *n; | |
483 | ||
484 | if (op->skip) | |
485 | return bio_invalidate(cl); | |
486 | ||
487 | if (atomic_sub_return(bio_sectors(bio), &op->c->sectors_to_gc) < 0) { | |
488 | set_gc_sectors(op->c); | |
489 | bch_queue_gc(op->c); | |
490 | } | |
491 | ||
492 | do { | |
493 | unsigned i; | |
494 | struct bkey *k; | |
495 | struct bio_set *split = s->d | |
496 | ? s->d->bio_split : op->c->bio_split; | |
497 | ||
498 | /* 1 for the device pointer and 1 for the chksum */ | |
499 | if (bch_keylist_realloc(&op->keys, | |
500 | 1 + (op->csum ? 1 : 0), | |
501 | op->c)) | |
502 | continue_at(cl, bch_journal, bcache_wq); | |
503 | ||
504 | k = op->keys.top; | |
505 | bkey_init(k); | |
506 | SET_KEY_INODE(k, op->inode); | |
507 | SET_KEY_OFFSET(k, bio->bi_sector); | |
508 | ||
509 | if (!bch_alloc_sectors(k, bio_sectors(bio), s)) | |
510 | goto err; | |
511 | ||
512 | n = bch_bio_split(bio, KEY_SIZE(k), GFP_NOIO, split); | |
513 | if (!n) { | |
514 | __bkey_put(op->c, k); | |
515 | continue_at(cl, bch_insert_data_loop, bcache_wq); | |
516 | } | |
517 | ||
518 | n->bi_end_io = bch_insert_data_endio; | |
519 | n->bi_private = cl; | |
520 | ||
521 | if (s->writeback) { | |
522 | SET_KEY_DIRTY(k, true); | |
523 | ||
524 | for (i = 0; i < KEY_PTRS(k); i++) | |
525 | SET_GC_MARK(PTR_BUCKET(op->c, k, i), | |
526 | GC_MARK_DIRTY); | |
527 | } | |
528 | ||
529 | SET_KEY_CSUM(k, op->csum); | |
530 | if (KEY_CSUM(k)) | |
531 | bio_csum(n, k); | |
532 | ||
533 | pr_debug("%s", pkey(k)); | |
534 | bch_keylist_push(&op->keys); | |
535 | ||
536 | trace_bcache_cache_insert(n, n->bi_sector, n->bi_bdev); | |
537 | n->bi_rw |= REQ_WRITE; | |
538 | bch_submit_bbio(n, op->c, k, 0); | |
539 | } while (n != bio); | |
540 | ||
541 | op->insert_data_done = true; | |
542 | continue_at(cl, bch_journal, bcache_wq); | |
543 | err: | |
544 | /* bch_alloc_sectors() blocks if s->writeback = true */ | |
545 | BUG_ON(s->writeback); | |
546 | ||
547 | /* | |
548 | * But if it's not a writeback write we'd rather just bail out if | |
549 | * there aren't any buckets ready to write to - it might take awhile and | |
550 | * we might be starving btree writes for gc or something. | |
551 | */ | |
552 | ||
553 | if (s->write) { | |
554 | /* | |
555 | * Writethrough write: We can't complete the write until we've | |
556 | * updated the index. But we don't want to delay the write while | |
557 | * we wait for buckets to be freed up, so just invalidate the | |
558 | * rest of the write. | |
559 | */ | |
560 | op->skip = true; | |
561 | return bio_invalidate(cl); | |
562 | } else { | |
563 | /* | |
564 | * From a cache miss, we can just insert the keys for the data | |
565 | * we have written or bail out if we didn't do anything. | |
566 | */ | |
567 | op->insert_data_done = true; | |
568 | bio_put(bio); | |
569 | ||
570 | if (!bch_keylist_empty(&op->keys)) | |
571 | continue_at(cl, bch_journal, bcache_wq); | |
572 | else | |
573 | closure_return(cl); | |
574 | } | |
575 | } | |
576 | ||
577 | /** | |
578 | * bch_insert_data - stick some data in the cache | |
579 | * | |
580 | * This is the starting point for any data to end up in a cache device; it could | |
581 | * be from a normal write, or a writeback write, or a write to a flash only | |
582 | * volume - it's also used by the moving garbage collector to compact data in | |
583 | * mostly empty buckets. | |
584 | * | |
585 | * It first writes the data to the cache, creating a list of keys to be inserted | |
586 | * (if the data had to be fragmented there will be multiple keys); after the | |
587 | * data is written it calls bch_journal, and after the keys have been added to | |
588 | * the next journal write they're inserted into the btree. | |
589 | * | |
590 | * It inserts the data in op->cache_bio; bi_sector is used for the key offset, | |
591 | * and op->inode is used for the key inode. | |
592 | * | |
593 | * If op->skip is true, instead of inserting the data it invalidates the region | |
594 | * of the cache represented by op->cache_bio and op->inode. | |
595 | */ | |
596 | void bch_insert_data(struct closure *cl) | |
597 | { | |
598 | struct btree_op *op = container_of(cl, struct btree_op, cl); | |
599 | ||
600 | bch_keylist_init(&op->keys); | |
601 | bio_get(op->cache_bio); | |
602 | bch_insert_data_loop(cl); | |
603 | } | |
604 | ||
605 | void bch_btree_insert_async(struct closure *cl) | |
606 | { | |
607 | struct btree_op *op = container_of(cl, struct btree_op, cl); | |
608 | struct search *s = container_of(op, struct search, op); | |
609 | ||
610 | if (bch_btree_insert(op, op->c)) { | |
611 | s->error = -ENOMEM; | |
612 | op->insert_data_done = true; | |
613 | } | |
614 | ||
615 | if (op->insert_data_done) { | |
616 | bch_keylist_free(&op->keys); | |
617 | closure_return(cl); | |
618 | } else | |
619 | continue_at(cl, bch_insert_data_loop, bcache_wq); | |
620 | } | |
621 | ||
622 | /* Common code for the make_request functions */ | |
623 | ||
624 | static void request_endio(struct bio *bio, int error) | |
625 | { | |
626 | struct closure *cl = bio->bi_private; | |
627 | ||
628 | if (error) { | |
629 | struct search *s = container_of(cl, struct search, cl); | |
630 | s->error = error; | |
631 | /* Only cache read errors are recoverable */ | |
632 | s->recoverable = false; | |
633 | } | |
634 | ||
635 | bio_put(bio); | |
636 | closure_put(cl); | |
637 | } | |
638 | ||
639 | void bch_cache_read_endio(struct bio *bio, int error) | |
640 | { | |
641 | struct bbio *b = container_of(bio, struct bbio, bio); | |
642 | struct closure *cl = bio->bi_private; | |
643 | struct search *s = container_of(cl, struct search, cl); | |
644 | ||
645 | /* | |
646 | * If the bucket was reused while our bio was in flight, we might have | |
647 | * read the wrong data. Set s->error but not error so it doesn't get | |
648 | * counted against the cache device, but we'll still reread the data | |
649 | * from the backing device. | |
650 | */ | |
651 | ||
652 | if (error) | |
653 | s->error = error; | |
654 | else if (ptr_stale(s->op.c, &b->key, 0)) { | |
655 | atomic_long_inc(&s->op.c->cache_read_races); | |
656 | s->error = -EINTR; | |
657 | } | |
658 | ||
659 | bch_bbio_endio(s->op.c, bio, error, "reading from cache"); | |
660 | } | |
661 | ||
662 | static void bio_complete(struct search *s) | |
663 | { | |
664 | if (s->orig_bio) { | |
665 | int cpu, rw = bio_data_dir(s->orig_bio); | |
666 | unsigned long duration = jiffies - s->start_time; | |
667 | ||
668 | cpu = part_stat_lock(); | |
669 | part_round_stats(cpu, &s->d->disk->part0); | |
670 | part_stat_add(cpu, &s->d->disk->part0, ticks[rw], duration); | |
671 | part_stat_unlock(); | |
672 | ||
673 | trace_bcache_request_end(s, s->orig_bio); | |
674 | bio_endio(s->orig_bio, s->error); | |
675 | s->orig_bio = NULL; | |
676 | } | |
677 | } | |
678 | ||
679 | static void do_bio_hook(struct search *s) | |
680 | { | |
681 | struct bio *bio = &s->bio.bio; | |
682 | memcpy(bio, s->orig_bio, sizeof(struct bio)); | |
683 | ||
684 | bio->bi_end_io = request_endio; | |
685 | bio->bi_private = &s->cl; | |
686 | atomic_set(&bio->bi_cnt, 3); | |
687 | } | |
688 | ||
689 | static void search_free(struct closure *cl) | |
690 | { | |
691 | struct search *s = container_of(cl, struct search, cl); | |
692 | bio_complete(s); | |
693 | ||
694 | if (s->op.cache_bio) | |
695 | bio_put(s->op.cache_bio); | |
696 | ||
697 | if (s->unaligned_bvec) | |
698 | mempool_free(s->bio.bio.bi_io_vec, s->d->unaligned_bvec); | |
699 | ||
700 | closure_debug_destroy(cl); | |
701 | mempool_free(s, s->d->c->search); | |
702 | } | |
703 | ||
704 | static struct search *search_alloc(struct bio *bio, struct bcache_device *d) | |
705 | { | |
706 | struct bio_vec *bv; | |
707 | struct search *s = mempool_alloc(d->c->search, GFP_NOIO); | |
708 | memset(s, 0, offsetof(struct search, op.keys)); | |
709 | ||
710 | __closure_init(&s->cl, NULL); | |
711 | ||
712 | s->op.inode = d->id; | |
713 | s->op.c = d->c; | |
714 | s->d = d; | |
715 | s->op.lock = -1; | |
716 | s->task = current; | |
717 | s->orig_bio = bio; | |
718 | s->write = (bio->bi_rw & REQ_WRITE) != 0; | |
719 | s->op.flush_journal = (bio->bi_rw & REQ_FLUSH) != 0; | |
720 | s->op.skip = (bio->bi_rw & REQ_DISCARD) != 0; | |
721 | s->recoverable = 1; | |
722 | s->start_time = jiffies; | |
723 | do_bio_hook(s); | |
724 | ||
725 | if (bio->bi_size != bio_segments(bio) * PAGE_SIZE) { | |
726 | bv = mempool_alloc(d->unaligned_bvec, GFP_NOIO); | |
727 | memcpy(bv, bio_iovec(bio), | |
728 | sizeof(struct bio_vec) * bio_segments(bio)); | |
729 | ||
730 | s->bio.bio.bi_io_vec = bv; | |
731 | s->unaligned_bvec = 1; | |
732 | } | |
733 | ||
734 | return s; | |
735 | } | |
736 | ||
737 | static void btree_read_async(struct closure *cl) | |
738 | { | |
739 | struct btree_op *op = container_of(cl, struct btree_op, cl); | |
740 | ||
741 | int ret = btree_root(search_recurse, op->c, op); | |
742 | ||
743 | if (ret == -EAGAIN) | |
744 | continue_at(cl, btree_read_async, bcache_wq); | |
745 | ||
746 | closure_return(cl); | |
747 | } | |
748 | ||
749 | /* Cached devices */ | |
750 | ||
751 | static void cached_dev_bio_complete(struct closure *cl) | |
752 | { | |
753 | struct search *s = container_of(cl, struct search, cl); | |
754 | struct cached_dev *dc = container_of(s->d, struct cached_dev, disk); | |
755 | ||
756 | search_free(cl); | |
757 | cached_dev_put(dc); | |
758 | } | |
759 | ||
760 | /* Process reads */ | |
761 | ||
762 | static void cached_dev_read_complete(struct closure *cl) | |
763 | { | |
764 | struct search *s = container_of(cl, struct search, cl); | |
765 | ||
766 | if (s->op.insert_collision) | |
767 | bch_mark_cache_miss_collision(s); | |
768 | ||
769 | if (s->op.cache_bio) { | |
770 | int i; | |
771 | struct bio_vec *bv; | |
772 | ||
773 | __bio_for_each_segment(bv, s->op.cache_bio, i, 0) | |
774 | __free_page(bv->bv_page); | |
775 | } | |
776 | ||
777 | cached_dev_bio_complete(cl); | |
778 | } | |
779 | ||
780 | static void request_read_error(struct closure *cl) | |
781 | { | |
782 | struct search *s = container_of(cl, struct search, cl); | |
783 | struct bio_vec *bv; | |
784 | int i; | |
785 | ||
786 | if (s->recoverable) { | |
787 | /* The cache read failed, but we can retry from the backing | |
788 | * device. | |
789 | */ | |
790 | pr_debug("recovering at sector %llu", | |
791 | (uint64_t) s->orig_bio->bi_sector); | |
792 | ||
793 | s->error = 0; | |
794 | bv = s->bio.bio.bi_io_vec; | |
795 | do_bio_hook(s); | |
796 | s->bio.bio.bi_io_vec = bv; | |
797 | ||
798 | if (!s->unaligned_bvec) | |
799 | bio_for_each_segment(bv, s->orig_bio, i) | |
800 | bv->bv_offset = 0, bv->bv_len = PAGE_SIZE; | |
801 | else | |
802 | memcpy(s->bio.bio.bi_io_vec, | |
803 | bio_iovec(s->orig_bio), | |
804 | sizeof(struct bio_vec) * | |
805 | bio_segments(s->orig_bio)); | |
806 | ||
807 | /* XXX: invalidate cache */ | |
808 | ||
809 | trace_bcache_read_retry(&s->bio.bio); | |
810 | closure_bio_submit(&s->bio.bio, &s->cl, s->d); | |
811 | } | |
812 | ||
813 | continue_at(cl, cached_dev_read_complete, NULL); | |
814 | } | |
815 | ||
816 | static void request_read_done(struct closure *cl) | |
817 | { | |
818 | struct search *s = container_of(cl, struct search, cl); | |
819 | struct cached_dev *dc = container_of(s->d, struct cached_dev, disk); | |
820 | ||
821 | /* | |
822 | * s->cache_bio != NULL implies that we had a cache miss; cache_bio now | |
823 | * contains data ready to be inserted into the cache. | |
824 | * | |
825 | * First, we copy the data we just read from cache_bio's bounce buffers | |
826 | * to the buffers the original bio pointed to: | |
827 | */ | |
828 | ||
829 | if (s->op.cache_bio) { | |
830 | struct bio_vec *src, *dst; | |
831 | unsigned src_offset, dst_offset, bytes; | |
832 | void *dst_ptr; | |
833 | ||
834 | bio_reset(s->op.cache_bio); | |
835 | s->op.cache_bio->bi_sector = s->cache_miss->bi_sector; | |
836 | s->op.cache_bio->bi_bdev = s->cache_miss->bi_bdev; | |
837 | s->op.cache_bio->bi_size = s->cache_bio_sectors << 9; | |
169ef1cf | 838 | bch_bio_map(s->op.cache_bio, NULL); |
cafe5635 KO |
839 | |
840 | src = bio_iovec(s->op.cache_bio); | |
841 | dst = bio_iovec(s->cache_miss); | |
842 | src_offset = src->bv_offset; | |
843 | dst_offset = dst->bv_offset; | |
844 | dst_ptr = kmap(dst->bv_page); | |
845 | ||
846 | while (1) { | |
847 | if (dst_offset == dst->bv_offset + dst->bv_len) { | |
848 | kunmap(dst->bv_page); | |
849 | dst++; | |
850 | if (dst == bio_iovec_idx(s->cache_miss, | |
851 | s->cache_miss->bi_vcnt)) | |
852 | break; | |
853 | ||
854 | dst_offset = dst->bv_offset; | |
855 | dst_ptr = kmap(dst->bv_page); | |
856 | } | |
857 | ||
858 | if (src_offset == src->bv_offset + src->bv_len) { | |
859 | src++; | |
860 | if (src == bio_iovec_idx(s->op.cache_bio, | |
861 | s->op.cache_bio->bi_vcnt)) | |
862 | BUG(); | |
863 | ||
864 | src_offset = src->bv_offset; | |
865 | } | |
866 | ||
867 | bytes = min(dst->bv_offset + dst->bv_len - dst_offset, | |
868 | src->bv_offset + src->bv_len - src_offset); | |
869 | ||
870 | memcpy(dst_ptr + dst_offset, | |
871 | page_address(src->bv_page) + src_offset, | |
872 | bytes); | |
873 | ||
874 | src_offset += bytes; | |
875 | dst_offset += bytes; | |
876 | } | |
877 | ||
878 | bio_put(s->cache_miss); | |
879 | s->cache_miss = NULL; | |
880 | } | |
881 | ||
882 | if (verify(dc, &s->bio.bio) && s->recoverable) | |
883 | bch_data_verify(s); | |
884 | ||
885 | bio_complete(s); | |
886 | ||
887 | if (s->op.cache_bio && | |
888 | !test_bit(CACHE_SET_STOPPING, &s->op.c->flags)) { | |
889 | s->op.type = BTREE_REPLACE; | |
890 | closure_call(&s->op.cl, bch_insert_data, NULL, cl); | |
891 | } | |
892 | ||
893 | continue_at(cl, cached_dev_read_complete, NULL); | |
894 | } | |
895 | ||
896 | static void request_read_done_bh(struct closure *cl) | |
897 | { | |
898 | struct search *s = container_of(cl, struct search, cl); | |
899 | struct cached_dev *dc = container_of(s->d, struct cached_dev, disk); | |
900 | ||
901 | bch_mark_cache_accounting(s, !s->cache_miss, s->op.skip); | |
902 | ||
903 | if (s->error) | |
904 | continue_at_nobarrier(cl, request_read_error, bcache_wq); | |
905 | else if (s->op.cache_bio || verify(dc, &s->bio.bio)) | |
906 | continue_at_nobarrier(cl, request_read_done, bcache_wq); | |
907 | else | |
908 | continue_at_nobarrier(cl, cached_dev_read_complete, NULL); | |
909 | } | |
910 | ||
911 | static int cached_dev_cache_miss(struct btree *b, struct search *s, | |
912 | struct bio *bio, unsigned sectors) | |
913 | { | |
914 | int ret = 0; | |
915 | unsigned reada; | |
916 | struct cached_dev *dc = container_of(s->d, struct cached_dev, disk); | |
917 | struct bio *miss; | |
918 | ||
919 | miss = bch_bio_split(bio, sectors, GFP_NOIO, s->d->bio_split); | |
920 | if (!miss) | |
921 | return -EAGAIN; | |
922 | ||
923 | if (miss == bio) | |
924 | s->op.lookup_done = true; | |
925 | ||
926 | miss->bi_end_io = request_endio; | |
927 | miss->bi_private = &s->cl; | |
928 | ||
929 | if (s->cache_miss || s->op.skip) | |
930 | goto out_submit; | |
931 | ||
932 | if (miss != bio || | |
933 | (bio->bi_rw & REQ_RAHEAD) || | |
934 | (bio->bi_rw & REQ_META) || | |
935 | s->op.c->gc_stats.in_use >= CUTOFF_CACHE_READA) | |
936 | reada = 0; | |
937 | else { | |
938 | reada = min(dc->readahead >> 9, | |
939 | sectors - bio_sectors(miss)); | |
940 | ||
941 | if (bio_end(miss) + reada > bdev_sectors(miss->bi_bdev)) | |
942 | reada = bdev_sectors(miss->bi_bdev) - bio_end(miss); | |
943 | } | |
944 | ||
945 | s->cache_bio_sectors = bio_sectors(miss) + reada; | |
946 | s->op.cache_bio = bio_alloc_bioset(GFP_NOWAIT, | |
947 | DIV_ROUND_UP(s->cache_bio_sectors, PAGE_SECTORS), | |
948 | dc->disk.bio_split); | |
949 | ||
950 | if (!s->op.cache_bio) | |
951 | goto out_submit; | |
952 | ||
953 | s->op.cache_bio->bi_sector = miss->bi_sector; | |
954 | s->op.cache_bio->bi_bdev = miss->bi_bdev; | |
955 | s->op.cache_bio->bi_size = s->cache_bio_sectors << 9; | |
956 | ||
957 | s->op.cache_bio->bi_end_io = request_endio; | |
958 | s->op.cache_bio->bi_private = &s->cl; | |
959 | ||
960 | /* btree_search_recurse()'s btree iterator is no good anymore */ | |
961 | ret = -EINTR; | |
962 | if (!bch_btree_insert_check_key(b, &s->op, s->op.cache_bio)) | |
963 | goto out_put; | |
964 | ||
169ef1cf KO |
965 | bch_bio_map(s->op.cache_bio, NULL); |
966 | if (bch_bio_alloc_pages(s->op.cache_bio, __GFP_NOWARN|GFP_NOIO)) | |
cafe5635 KO |
967 | goto out_put; |
968 | ||
969 | s->cache_miss = miss; | |
970 | bio_get(s->op.cache_bio); | |
971 | ||
972 | trace_bcache_cache_miss(s->orig_bio); | |
973 | closure_bio_submit(s->op.cache_bio, &s->cl, s->d); | |
974 | ||
975 | return ret; | |
976 | out_put: | |
977 | bio_put(s->op.cache_bio); | |
978 | s->op.cache_bio = NULL; | |
979 | out_submit: | |
980 | closure_bio_submit(miss, &s->cl, s->d); | |
981 | return ret; | |
982 | } | |
983 | ||
984 | static void request_read(struct cached_dev *dc, struct search *s) | |
985 | { | |
986 | struct closure *cl = &s->cl; | |
987 | ||
988 | check_should_skip(dc, s); | |
989 | closure_call(&s->op.cl, btree_read_async, NULL, cl); | |
990 | ||
991 | continue_at(cl, request_read_done_bh, NULL); | |
992 | } | |
993 | ||
994 | /* Process writes */ | |
995 | ||
996 | static void cached_dev_write_complete(struct closure *cl) | |
997 | { | |
998 | struct search *s = container_of(cl, struct search, cl); | |
999 | struct cached_dev *dc = container_of(s->d, struct cached_dev, disk); | |
1000 | ||
1001 | up_read_non_owner(&dc->writeback_lock); | |
1002 | cached_dev_bio_complete(cl); | |
1003 | } | |
1004 | ||
1005 | static bool should_writeback(struct cached_dev *dc, struct bio *bio) | |
1006 | { | |
1007 | unsigned threshold = (bio->bi_rw & REQ_SYNC) | |
1008 | ? CUTOFF_WRITEBACK_SYNC | |
1009 | : CUTOFF_WRITEBACK; | |
1010 | ||
1011 | return !atomic_read(&dc->disk.detaching) && | |
1012 | cache_mode(dc, bio) == CACHE_MODE_WRITEBACK && | |
1013 | dc->disk.c->gc_stats.in_use < threshold; | |
1014 | } | |
1015 | ||
1016 | static void request_write(struct cached_dev *dc, struct search *s) | |
1017 | { | |
1018 | struct closure *cl = &s->cl; | |
1019 | struct bio *bio = &s->bio.bio; | |
1020 | struct bkey start, end; | |
1021 | start = KEY(dc->disk.id, bio->bi_sector, 0); | |
1022 | end = KEY(dc->disk.id, bio_end(bio), 0); | |
1023 | ||
1024 | bch_keybuf_check_overlapping(&s->op.c->moving_gc_keys, &start, &end); | |
1025 | ||
1026 | check_should_skip(dc, s); | |
1027 | down_read_non_owner(&dc->writeback_lock); | |
1028 | ||
1029 | if (bch_keybuf_check_overlapping(&dc->writeback_keys, &start, &end)) { | |
1030 | s->op.skip = false; | |
1031 | s->writeback = true; | |
1032 | } | |
1033 | ||
1034 | if (bio->bi_rw & REQ_DISCARD) | |
1035 | goto skip; | |
1036 | ||
1037 | if (s->op.skip) | |
1038 | goto skip; | |
1039 | ||
1040 | if (should_writeback(dc, s->orig_bio)) | |
1041 | s->writeback = true; | |
1042 | ||
1043 | if (!s->writeback) { | |
1044 | s->op.cache_bio = bio_clone_bioset(bio, GFP_NOIO, | |
1045 | dc->disk.bio_split); | |
1046 | ||
1047 | trace_bcache_writethrough(s->orig_bio); | |
1048 | closure_bio_submit(bio, cl, s->d); | |
1049 | } else { | |
1050 | s->op.cache_bio = bio; | |
1051 | trace_bcache_writeback(s->orig_bio); | |
1052 | bch_writeback_add(dc, bio_sectors(bio)); | |
1053 | } | |
1054 | out: | |
1055 | closure_call(&s->op.cl, bch_insert_data, NULL, cl); | |
1056 | continue_at(cl, cached_dev_write_complete, NULL); | |
1057 | skip: | |
1058 | s->op.skip = true; | |
1059 | s->op.cache_bio = s->orig_bio; | |
1060 | bio_get(s->op.cache_bio); | |
1061 | trace_bcache_write_skip(s->orig_bio); | |
1062 | ||
1063 | if ((bio->bi_rw & REQ_DISCARD) && | |
1064 | !blk_queue_discard(bdev_get_queue(dc->bdev))) | |
1065 | goto out; | |
1066 | ||
1067 | closure_bio_submit(bio, cl, s->d); | |
1068 | goto out; | |
1069 | } | |
1070 | ||
1071 | static void request_nodata(struct cached_dev *dc, struct search *s) | |
1072 | { | |
1073 | struct closure *cl = &s->cl; | |
1074 | struct bio *bio = &s->bio.bio; | |
1075 | ||
1076 | if (bio->bi_rw & REQ_DISCARD) { | |
1077 | request_write(dc, s); | |
1078 | return; | |
1079 | } | |
1080 | ||
1081 | if (s->op.flush_journal) | |
1082 | bch_journal_meta(s->op.c, cl); | |
1083 | ||
1084 | closure_bio_submit(bio, cl, s->d); | |
1085 | ||
1086 | continue_at(cl, cached_dev_bio_complete, NULL); | |
1087 | } | |
1088 | ||
1089 | /* Cached devices - read & write stuff */ | |
1090 | ||
1091 | int bch_get_congested(struct cache_set *c) | |
1092 | { | |
1093 | int i; | |
1094 | ||
1095 | if (!c->congested_read_threshold_us && | |
1096 | !c->congested_write_threshold_us) | |
1097 | return 0; | |
1098 | ||
1099 | i = (local_clock_us() - c->congested_last_us) / 1024; | |
1100 | if (i < 0) | |
1101 | return 0; | |
1102 | ||
1103 | i += atomic_read(&c->congested); | |
1104 | if (i >= 0) | |
1105 | return 0; | |
1106 | ||
1107 | i += CONGESTED_MAX; | |
1108 | ||
1109 | return i <= 0 ? 1 : fract_exp_two(i, 6); | |
1110 | } | |
1111 | ||
1112 | static void add_sequential(struct task_struct *t) | |
1113 | { | |
1114 | ewma_add(t->sequential_io_avg, | |
1115 | t->sequential_io, 8, 0); | |
1116 | ||
1117 | t->sequential_io = 0; | |
1118 | } | |
1119 | ||
b1a67b0f | 1120 | static struct hlist_head *iohash(struct cached_dev *dc, uint64_t k) |
cafe5635 | 1121 | { |
b1a67b0f KO |
1122 | return &dc->io_hash[hash_64(k, RECENT_IO_BITS)]; |
1123 | } | |
cafe5635 | 1124 | |
b1a67b0f KO |
1125 | static void check_should_skip(struct cached_dev *dc, struct search *s) |
1126 | { | |
cafe5635 KO |
1127 | struct cache_set *c = s->op.c; |
1128 | struct bio *bio = &s->bio.bio; | |
1129 | ||
1130 | long rand; | |
1131 | int cutoff = bch_get_congested(c); | |
1132 | unsigned mode = cache_mode(dc, bio); | |
1133 | ||
1134 | if (atomic_read(&dc->disk.detaching) || | |
1135 | c->gc_stats.in_use > CUTOFF_CACHE_ADD || | |
1136 | (bio->bi_rw & REQ_DISCARD)) | |
1137 | goto skip; | |
1138 | ||
1139 | if (mode == CACHE_MODE_NONE || | |
1140 | (mode == CACHE_MODE_WRITEAROUND && | |
1141 | (bio->bi_rw & REQ_WRITE))) | |
1142 | goto skip; | |
1143 | ||
1144 | if (bio->bi_sector & (c->sb.block_size - 1) || | |
1145 | bio_sectors(bio) & (c->sb.block_size - 1)) { | |
1146 | pr_debug("skipping unaligned io"); | |
1147 | goto skip; | |
1148 | } | |
1149 | ||
1150 | if (!cutoff) { | |
1151 | cutoff = dc->sequential_cutoff >> 9; | |
1152 | ||
1153 | if (!cutoff) | |
1154 | goto rescale; | |
1155 | ||
1156 | if (mode == CACHE_MODE_WRITEBACK && | |
1157 | (bio->bi_rw & REQ_WRITE) && | |
1158 | (bio->bi_rw & REQ_SYNC)) | |
1159 | goto rescale; | |
1160 | } | |
1161 | ||
1162 | if (dc->sequential_merge) { | |
1163 | struct io *i; | |
1164 | ||
1165 | spin_lock(&dc->io_lock); | |
1166 | ||
b1a67b0f | 1167 | hlist_for_each_entry(i, iohash(dc, bio->bi_sector), hash) |
cafe5635 KO |
1168 | if (i->last == bio->bi_sector && |
1169 | time_before(jiffies, i->jiffies)) | |
1170 | goto found; | |
1171 | ||
1172 | i = list_first_entry(&dc->io_lru, struct io, lru); | |
1173 | ||
1174 | add_sequential(s->task); | |
1175 | i->sequential = 0; | |
1176 | found: | |
1177 | if (i->sequential + bio->bi_size > i->sequential) | |
1178 | i->sequential += bio->bi_size; | |
1179 | ||
1180 | i->last = bio_end(bio); | |
1181 | i->jiffies = jiffies + msecs_to_jiffies(5000); | |
1182 | s->task->sequential_io = i->sequential; | |
1183 | ||
1184 | hlist_del(&i->hash); | |
b1a67b0f | 1185 | hlist_add_head(&i->hash, iohash(dc, i->last)); |
cafe5635 KO |
1186 | list_move_tail(&i->lru, &dc->io_lru); |
1187 | ||
1188 | spin_unlock(&dc->io_lock); | |
1189 | } else { | |
1190 | s->task->sequential_io = bio->bi_size; | |
1191 | ||
1192 | add_sequential(s->task); | |
1193 | } | |
1194 | ||
1195 | rand = get_random_int(); | |
1196 | cutoff -= bitmap_weight(&rand, BITS_PER_LONG); | |
1197 | ||
1198 | if (cutoff <= (int) (max(s->task->sequential_io, | |
1199 | s->task->sequential_io_avg) >> 9)) | |
1200 | goto skip; | |
1201 | ||
1202 | rescale: | |
1203 | bch_rescale_priorities(c, bio_sectors(bio)); | |
1204 | return; | |
1205 | skip: | |
1206 | bch_mark_sectors_bypassed(s, bio_sectors(bio)); | |
1207 | s->op.skip = true; | |
1208 | } | |
1209 | ||
1210 | static void cached_dev_make_request(struct request_queue *q, struct bio *bio) | |
1211 | { | |
1212 | struct search *s; | |
1213 | struct bcache_device *d = bio->bi_bdev->bd_disk->private_data; | |
1214 | struct cached_dev *dc = container_of(d, struct cached_dev, disk); | |
1215 | int cpu, rw = bio_data_dir(bio); | |
1216 | ||
1217 | cpu = part_stat_lock(); | |
1218 | part_stat_inc(cpu, &d->disk->part0, ios[rw]); | |
1219 | part_stat_add(cpu, &d->disk->part0, sectors[rw], bio_sectors(bio)); | |
1220 | part_stat_unlock(); | |
1221 | ||
1222 | bio->bi_bdev = dc->bdev; | |
2903381f | 1223 | bio->bi_sector += dc->sb.data_offset; |
cafe5635 KO |
1224 | |
1225 | if (cached_dev_get(dc)) { | |
1226 | s = search_alloc(bio, d); | |
1227 | trace_bcache_request_start(s, bio); | |
1228 | ||
1229 | if (!bio_has_data(bio)) | |
1230 | request_nodata(dc, s); | |
1231 | else if (rw) | |
1232 | request_write(dc, s); | |
1233 | else | |
1234 | request_read(dc, s); | |
1235 | } else { | |
1236 | if ((bio->bi_rw & REQ_DISCARD) && | |
1237 | !blk_queue_discard(bdev_get_queue(dc->bdev))) | |
1238 | bio_endio(bio, 0); | |
1239 | else | |
1240 | bch_generic_make_request(bio, &d->bio_split_hook); | |
1241 | } | |
1242 | } | |
1243 | ||
1244 | static int cached_dev_ioctl(struct bcache_device *d, fmode_t mode, | |
1245 | unsigned int cmd, unsigned long arg) | |
1246 | { | |
1247 | struct cached_dev *dc = container_of(d, struct cached_dev, disk); | |
1248 | return __blkdev_driver_ioctl(dc->bdev, mode, cmd, arg); | |
1249 | } | |
1250 | ||
1251 | static int cached_dev_congested(void *data, int bits) | |
1252 | { | |
1253 | struct bcache_device *d = data; | |
1254 | struct cached_dev *dc = container_of(d, struct cached_dev, disk); | |
1255 | struct request_queue *q = bdev_get_queue(dc->bdev); | |
1256 | int ret = 0; | |
1257 | ||
1258 | if (bdi_congested(&q->backing_dev_info, bits)) | |
1259 | return 1; | |
1260 | ||
1261 | if (cached_dev_get(dc)) { | |
1262 | unsigned i; | |
1263 | struct cache *ca; | |
1264 | ||
1265 | for_each_cache(ca, d->c, i) { | |
1266 | q = bdev_get_queue(ca->bdev); | |
1267 | ret |= bdi_congested(&q->backing_dev_info, bits); | |
1268 | } | |
1269 | ||
1270 | cached_dev_put(dc); | |
1271 | } | |
1272 | ||
1273 | return ret; | |
1274 | } | |
1275 | ||
1276 | void bch_cached_dev_request_init(struct cached_dev *dc) | |
1277 | { | |
1278 | struct gendisk *g = dc->disk.disk; | |
1279 | ||
1280 | g->queue->make_request_fn = cached_dev_make_request; | |
1281 | g->queue->backing_dev_info.congested_fn = cached_dev_congested; | |
1282 | dc->disk.cache_miss = cached_dev_cache_miss; | |
1283 | dc->disk.ioctl = cached_dev_ioctl; | |
1284 | } | |
1285 | ||
1286 | /* Flash backed devices */ | |
1287 | ||
1288 | static int flash_dev_cache_miss(struct btree *b, struct search *s, | |
1289 | struct bio *bio, unsigned sectors) | |
1290 | { | |
1291 | /* Zero fill bio */ | |
1292 | ||
1293 | while (bio->bi_idx != bio->bi_vcnt) { | |
1294 | struct bio_vec *bv = bio_iovec(bio); | |
1295 | unsigned j = min(bv->bv_len >> 9, sectors); | |
1296 | ||
1297 | void *p = kmap(bv->bv_page); | |
1298 | memset(p + bv->bv_offset, 0, j << 9); | |
1299 | kunmap(bv->bv_page); | |
1300 | ||
1301 | bv->bv_len -= j << 9; | |
1302 | bv->bv_offset += j << 9; | |
1303 | ||
1304 | if (bv->bv_len) | |
1305 | return 0; | |
1306 | ||
1307 | bio->bi_sector += j; | |
1308 | bio->bi_size -= j << 9; | |
1309 | ||
1310 | bio->bi_idx++; | |
1311 | sectors -= j; | |
1312 | } | |
1313 | ||
1314 | s->op.lookup_done = true; | |
1315 | ||
1316 | return 0; | |
1317 | } | |
1318 | ||
1319 | static void flash_dev_make_request(struct request_queue *q, struct bio *bio) | |
1320 | { | |
1321 | struct search *s; | |
1322 | struct closure *cl; | |
1323 | struct bcache_device *d = bio->bi_bdev->bd_disk->private_data; | |
1324 | int cpu, rw = bio_data_dir(bio); | |
1325 | ||
1326 | cpu = part_stat_lock(); | |
1327 | part_stat_inc(cpu, &d->disk->part0, ios[rw]); | |
1328 | part_stat_add(cpu, &d->disk->part0, sectors[rw], bio_sectors(bio)); | |
1329 | part_stat_unlock(); | |
1330 | ||
1331 | s = search_alloc(bio, d); | |
1332 | cl = &s->cl; | |
1333 | bio = &s->bio.bio; | |
1334 | ||
1335 | trace_bcache_request_start(s, bio); | |
1336 | ||
1337 | if (bio_has_data(bio) && !rw) { | |
1338 | closure_call(&s->op.cl, btree_read_async, NULL, cl); | |
1339 | } else if (bio_has_data(bio) || s->op.skip) { | |
1340 | bch_keybuf_check_overlapping(&s->op.c->moving_gc_keys, | |
1341 | &KEY(d->id, bio->bi_sector, 0), | |
1342 | &KEY(d->id, bio_end(bio), 0)); | |
1343 | ||
1344 | s->writeback = true; | |
1345 | s->op.cache_bio = bio; | |
1346 | ||
1347 | closure_call(&s->op.cl, bch_insert_data, NULL, cl); | |
1348 | } else { | |
1349 | /* No data - probably a cache flush */ | |
1350 | if (s->op.flush_journal) | |
1351 | bch_journal_meta(s->op.c, cl); | |
1352 | } | |
1353 | ||
1354 | continue_at(cl, search_free, NULL); | |
1355 | } | |
1356 | ||
1357 | static int flash_dev_ioctl(struct bcache_device *d, fmode_t mode, | |
1358 | unsigned int cmd, unsigned long arg) | |
1359 | { | |
1360 | return -ENOTTY; | |
1361 | } | |
1362 | ||
1363 | static int flash_dev_congested(void *data, int bits) | |
1364 | { | |
1365 | struct bcache_device *d = data; | |
1366 | struct request_queue *q; | |
1367 | struct cache *ca; | |
1368 | unsigned i; | |
1369 | int ret = 0; | |
1370 | ||
1371 | for_each_cache(ca, d->c, i) { | |
1372 | q = bdev_get_queue(ca->bdev); | |
1373 | ret |= bdi_congested(&q->backing_dev_info, bits); | |
1374 | } | |
1375 | ||
1376 | return ret; | |
1377 | } | |
1378 | ||
1379 | void bch_flash_dev_request_init(struct bcache_device *d) | |
1380 | { | |
1381 | struct gendisk *g = d->disk; | |
1382 | ||
1383 | g->queue->make_request_fn = flash_dev_make_request; | |
1384 | g->queue->backing_dev_info.congested_fn = flash_dev_congested; | |
1385 | d->cache_miss = flash_dev_cache_miss; | |
1386 | d->ioctl = flash_dev_ioctl; | |
1387 | } | |
1388 | ||
1389 | void bch_request_exit(void) | |
1390 | { | |
1391 | #ifdef CONFIG_CGROUP_BCACHE | |
1392 | cgroup_unload_subsys(&bcache_subsys); | |
1393 | #endif | |
1394 | if (bch_search_cache) | |
1395 | kmem_cache_destroy(bch_search_cache); | |
1396 | } | |
1397 | ||
1398 | int __init bch_request_init(void) | |
1399 | { | |
1400 | bch_search_cache = KMEM_CACHE(search, 0); | |
1401 | if (!bch_search_cache) | |
1402 | return -ENOMEM; | |
1403 | ||
1404 | #ifdef CONFIG_CGROUP_BCACHE | |
1405 | cgroup_load_subsys(&bcache_subsys); | |
1406 | init_bch_cgroup(&bcache_default_cgroup); | |
1407 | ||
1408 | cgroup_add_cftypes(&bcache_subsys, bch_files); | |
1409 | #endif | |
1410 | return 0; | |
1411 | } |