Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Primary bucket allocation code |
| 3 | * |
| 4 | * Copyright 2012 Google, Inc. |
| 5 | * |
| 6 | * Allocation in bcache is done in terms of buckets: |
| 7 | * |
| 8 | * Each bucket has associated an 8 bit gen; this gen corresponds to the gen in |
| 9 | * btree pointers - they must match for the pointer to be considered valid. |
| 10 | * |
| 11 | * Thus (assuming a bucket has no dirty data or metadata in it) we can reuse a |
| 12 | * bucket simply by incrementing its gen. |
| 13 | * |
| 14 | * The gens (along with the priorities; it's really the gens are important but |
| 15 | * the code is named as if it's the priorities) are written in an arbitrary list |
| 16 | * of buckets on disk, with a pointer to them in the journal header. |
| 17 | * |
| 18 | * When we invalidate a bucket, we have to write its new gen to disk and wait |
| 19 | * for that write to complete before we use it - otherwise after a crash we |
| 20 | * could have pointers that appeared to be good but pointed to data that had |
| 21 | * been overwritten. |
| 22 | * |
| 23 | * Since the gens and priorities are all stored contiguously on disk, we can |
| 24 | * batch this up: We fill up the free_inc list with freshly invalidated buckets, |
| 25 | * call prio_write(), and when prio_write() finishes we pull buckets off the |
| 26 | * free_inc list and optionally discard them. |
| 27 | * |
| 28 | * free_inc isn't the only freelist - if it was, we'd often to sleep while |
| 29 | * priorities and gens were being written before we could allocate. c->free is a |
| 30 | * smaller freelist, and buckets on that list are always ready to be used. |
| 31 | * |
| 32 | * If we've got discards enabled, that happens when a bucket moves from the |
| 33 | * free_inc list to the free list. |
| 34 | * |
| 35 | * There is another freelist, because sometimes we have buckets that we know |
| 36 | * have nothing pointing into them - these we can reuse without waiting for |
| 37 | * priorities to be rewritten. These come from freed btree nodes and buckets |
| 38 | * that garbage collection discovered no longer had valid keys pointing into |
| 39 | * them (because they were overwritten). That's the unused list - buckets on the |
| 40 | * unused list move to the free list, optionally being discarded in the process. |
| 41 | * |
| 42 | * It's also important to ensure that gens don't wrap around - with respect to |
| 43 | * either the oldest gen in the btree or the gen on disk. This is quite |
| 44 | * difficult to do in practice, but we explicitly guard against it anyways - if |
| 45 | * a bucket is in danger of wrapping around we simply skip invalidating it that |
| 46 | * time around, and we garbage collect or rewrite the priorities sooner than we |
| 47 | * would have otherwise. |
| 48 | * |
| 49 | * bch_bucket_alloc() allocates a single bucket from a specific cache. |
| 50 | * |
| 51 | * bch_bucket_alloc_set() allocates one or more buckets from different caches |
| 52 | * out of a cache set. |
| 53 | * |
| 54 | * free_some_buckets() drives all the processes described above. It's called |
| 55 | * from bch_bucket_alloc() and a few other places that need to make sure free |
| 56 | * buckets are ready. |
| 57 | * |
| 58 | * invalidate_buckets_(lru|fifo)() find buckets that are available to be |
| 59 | * invalidated, and then invalidate them and stick them on the free_inc list - |
| 60 | * in either lru or fifo order. |
| 61 | */ |
| 62 | |
| 63 | #include "bcache.h" |
| 64 | #include "btree.h" |
| 65 | |
Kent Overstreet | 119ba0f | 2013-04-24 19:01:12 -0700 | [diff] [blame^] | 66 | #include <linux/kthread.h> |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 67 | #include <linux/random.h> |
| 68 | |
| 69 | #define MAX_IN_FLIGHT_DISCARDS 8U |
| 70 | |
| 71 | /* Bucket heap / gen */ |
| 72 | |
| 73 | uint8_t bch_inc_gen(struct cache *ca, struct bucket *b) |
| 74 | { |
| 75 | uint8_t ret = ++b->gen; |
| 76 | |
| 77 | ca->set->need_gc = max(ca->set->need_gc, bucket_gc_gen(b)); |
| 78 | WARN_ON_ONCE(ca->set->need_gc > BUCKET_GC_GEN_MAX); |
| 79 | |
| 80 | if (CACHE_SYNC(&ca->set->sb)) { |
| 81 | ca->need_save_prio = max(ca->need_save_prio, |
| 82 | bucket_disk_gen(b)); |
| 83 | WARN_ON_ONCE(ca->need_save_prio > BUCKET_DISK_GEN_MAX); |
| 84 | } |
| 85 | |
| 86 | return ret; |
| 87 | } |
| 88 | |
| 89 | void bch_rescale_priorities(struct cache_set *c, int sectors) |
| 90 | { |
| 91 | struct cache *ca; |
| 92 | struct bucket *b; |
| 93 | unsigned next = c->nbuckets * c->sb.bucket_size / 1024; |
| 94 | unsigned i; |
| 95 | int r; |
| 96 | |
| 97 | atomic_sub(sectors, &c->rescale); |
| 98 | |
| 99 | do { |
| 100 | r = atomic_read(&c->rescale); |
| 101 | |
| 102 | if (r >= 0) |
| 103 | return; |
| 104 | } while (atomic_cmpxchg(&c->rescale, r, r + next) != r); |
| 105 | |
| 106 | mutex_lock(&c->bucket_lock); |
| 107 | |
| 108 | c->min_prio = USHRT_MAX; |
| 109 | |
| 110 | for_each_cache(ca, c, i) |
| 111 | for_each_bucket(b, ca) |
| 112 | if (b->prio && |
| 113 | b->prio != BTREE_PRIO && |
| 114 | !atomic_read(&b->pin)) { |
| 115 | b->prio--; |
| 116 | c->min_prio = min(c->min_prio, b->prio); |
| 117 | } |
| 118 | |
| 119 | mutex_unlock(&c->bucket_lock); |
| 120 | } |
| 121 | |
| 122 | /* Discard/TRIM */ |
| 123 | |
| 124 | struct discard { |
| 125 | struct list_head list; |
| 126 | struct work_struct work; |
| 127 | struct cache *ca; |
| 128 | long bucket; |
| 129 | |
| 130 | struct bio bio; |
| 131 | struct bio_vec bv; |
| 132 | }; |
| 133 | |
| 134 | static void discard_finish(struct work_struct *w) |
| 135 | { |
| 136 | struct discard *d = container_of(w, struct discard, work); |
| 137 | struct cache *ca = d->ca; |
| 138 | char buf[BDEVNAME_SIZE]; |
| 139 | |
| 140 | if (!test_bit(BIO_UPTODATE, &d->bio.bi_flags)) { |
| 141 | pr_notice("discard error on %s, disabling", |
| 142 | bdevname(ca->bdev, buf)); |
| 143 | d->ca->discard = 0; |
| 144 | } |
| 145 | |
| 146 | mutex_lock(&ca->set->bucket_lock); |
| 147 | |
| 148 | fifo_push(&ca->free, d->bucket); |
| 149 | list_add(&d->list, &ca->discards); |
| 150 | atomic_dec(&ca->discards_in_flight); |
| 151 | |
| 152 | mutex_unlock(&ca->set->bucket_lock); |
| 153 | |
| 154 | closure_wake_up(&ca->set->bucket_wait); |
Kent Overstreet | 119ba0f | 2013-04-24 19:01:12 -0700 | [diff] [blame^] | 155 | wake_up_process(ca->alloc_thread); |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 156 | |
| 157 | closure_put(&ca->set->cl); |
| 158 | } |
| 159 | |
| 160 | static void discard_endio(struct bio *bio, int error) |
| 161 | { |
| 162 | struct discard *d = container_of(bio, struct discard, bio); |
| 163 | schedule_work(&d->work); |
| 164 | } |
| 165 | |
| 166 | static void do_discard(struct cache *ca, long bucket) |
| 167 | { |
| 168 | struct discard *d = list_first_entry(&ca->discards, |
| 169 | struct discard, list); |
| 170 | |
| 171 | list_del(&d->list); |
| 172 | d->bucket = bucket; |
| 173 | |
| 174 | atomic_inc(&ca->discards_in_flight); |
| 175 | closure_get(&ca->set->cl); |
| 176 | |
| 177 | bio_init(&d->bio); |
| 178 | |
| 179 | d->bio.bi_sector = bucket_to_sector(ca->set, d->bucket); |
| 180 | d->bio.bi_bdev = ca->bdev; |
| 181 | d->bio.bi_rw = REQ_WRITE|REQ_DISCARD; |
| 182 | d->bio.bi_max_vecs = 1; |
| 183 | d->bio.bi_io_vec = d->bio.bi_inline_vecs; |
| 184 | d->bio.bi_size = bucket_bytes(ca); |
| 185 | d->bio.bi_end_io = discard_endio; |
| 186 | bio_set_prio(&d->bio, IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0)); |
| 187 | |
| 188 | submit_bio(0, &d->bio); |
| 189 | } |
| 190 | |
| 191 | /* Allocation */ |
| 192 | |
| 193 | static inline bool can_inc_bucket_gen(struct bucket *b) |
| 194 | { |
| 195 | return bucket_gc_gen(b) < BUCKET_GC_GEN_MAX && |
| 196 | bucket_disk_gen(b) < BUCKET_DISK_GEN_MAX; |
| 197 | } |
| 198 | |
| 199 | bool bch_bucket_add_unused(struct cache *ca, struct bucket *b) |
| 200 | { |
| 201 | BUG_ON(GC_MARK(b) || GC_SECTORS_USED(b)); |
| 202 | |
| 203 | if (fifo_used(&ca->free) > ca->watermark[WATERMARK_MOVINGGC] && |
| 204 | CACHE_REPLACEMENT(&ca->sb) == CACHE_REPLACEMENT_FIFO) |
| 205 | return false; |
| 206 | |
| 207 | b->prio = 0; |
| 208 | |
| 209 | if (can_inc_bucket_gen(b) && |
| 210 | fifo_push(&ca->unused, b - ca->buckets)) { |
| 211 | atomic_inc(&b->pin); |
| 212 | return true; |
| 213 | } |
| 214 | |
| 215 | return false; |
| 216 | } |
| 217 | |
| 218 | static bool can_invalidate_bucket(struct cache *ca, struct bucket *b) |
| 219 | { |
| 220 | return GC_MARK(b) == GC_MARK_RECLAIMABLE && |
| 221 | !atomic_read(&b->pin) && |
| 222 | can_inc_bucket_gen(b); |
| 223 | } |
| 224 | |
| 225 | static void invalidate_one_bucket(struct cache *ca, struct bucket *b) |
| 226 | { |
| 227 | bch_inc_gen(ca, b); |
| 228 | b->prio = INITIAL_PRIO; |
| 229 | atomic_inc(&b->pin); |
| 230 | fifo_push(&ca->free_inc, b - ca->buckets); |
| 231 | } |
| 232 | |
Kent Overstreet | b1a67b0 | 2013-03-25 11:46:44 -0700 | [diff] [blame] | 233 | #define bucket_prio(b) \ |
| 234 | (((unsigned) (b->prio - ca->set->min_prio)) * GC_SECTORS_USED(b)) |
| 235 | |
| 236 | #define bucket_max_cmp(l, r) (bucket_prio(l) < bucket_prio(r)) |
| 237 | #define bucket_min_cmp(l, r) (bucket_prio(l) > bucket_prio(r)) |
| 238 | |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 239 | static void invalidate_buckets_lru(struct cache *ca) |
| 240 | { |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 241 | struct bucket *b; |
| 242 | ssize_t i; |
| 243 | |
| 244 | ca->heap.used = 0; |
| 245 | |
| 246 | for_each_bucket(b, ca) { |
Kent Overstreet | 86b26b8 | 2013-04-30 19:14:40 -0700 | [diff] [blame] | 247 | /* |
| 248 | * If we fill up the unused list, if we then return before |
| 249 | * adding anything to the free_inc list we'll skip writing |
| 250 | * prios/gens and just go back to allocating from the unused |
| 251 | * list: |
| 252 | */ |
| 253 | if (fifo_full(&ca->unused)) |
| 254 | return; |
| 255 | |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 256 | if (!can_invalidate_bucket(ca, b)) |
| 257 | continue; |
| 258 | |
Kent Overstreet | 86b26b8 | 2013-04-30 19:14:40 -0700 | [diff] [blame] | 259 | if (!GC_SECTORS_USED(b) && |
| 260 | bch_bucket_add_unused(ca, b)) |
| 261 | continue; |
| 262 | |
| 263 | if (!heap_full(&ca->heap)) |
| 264 | heap_add(&ca->heap, b, bucket_max_cmp); |
| 265 | else if (bucket_max_cmp(b, heap_peek(&ca->heap))) { |
| 266 | ca->heap.data[0] = b; |
| 267 | heap_sift(&ca->heap, 0, bucket_max_cmp); |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 268 | } |
| 269 | } |
| 270 | |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 271 | for (i = ca->heap.used / 2 - 1; i >= 0; --i) |
| 272 | heap_sift(&ca->heap, i, bucket_min_cmp); |
| 273 | |
| 274 | while (!fifo_full(&ca->free_inc)) { |
| 275 | if (!heap_pop(&ca->heap, b, bucket_min_cmp)) { |
Kent Overstreet | 86b26b8 | 2013-04-30 19:14:40 -0700 | [diff] [blame] | 276 | /* |
| 277 | * We don't want to be calling invalidate_buckets() |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 278 | * multiple times when it can't do anything |
| 279 | */ |
| 280 | ca->invalidate_needs_gc = 1; |
| 281 | bch_queue_gc(ca->set); |
| 282 | return; |
| 283 | } |
| 284 | |
| 285 | invalidate_one_bucket(ca, b); |
| 286 | } |
| 287 | } |
| 288 | |
| 289 | static void invalidate_buckets_fifo(struct cache *ca) |
| 290 | { |
| 291 | struct bucket *b; |
| 292 | size_t checked = 0; |
| 293 | |
| 294 | while (!fifo_full(&ca->free_inc)) { |
| 295 | if (ca->fifo_last_bucket < ca->sb.first_bucket || |
| 296 | ca->fifo_last_bucket >= ca->sb.nbuckets) |
| 297 | ca->fifo_last_bucket = ca->sb.first_bucket; |
| 298 | |
| 299 | b = ca->buckets + ca->fifo_last_bucket++; |
| 300 | |
| 301 | if (can_invalidate_bucket(ca, b)) |
| 302 | invalidate_one_bucket(ca, b); |
| 303 | |
| 304 | if (++checked >= ca->sb.nbuckets) { |
| 305 | ca->invalidate_needs_gc = 1; |
| 306 | bch_queue_gc(ca->set); |
| 307 | return; |
| 308 | } |
| 309 | } |
| 310 | } |
| 311 | |
| 312 | static void invalidate_buckets_random(struct cache *ca) |
| 313 | { |
| 314 | struct bucket *b; |
| 315 | size_t checked = 0; |
| 316 | |
| 317 | while (!fifo_full(&ca->free_inc)) { |
| 318 | size_t n; |
| 319 | get_random_bytes(&n, sizeof(n)); |
| 320 | |
| 321 | n %= (size_t) (ca->sb.nbuckets - ca->sb.first_bucket); |
| 322 | n += ca->sb.first_bucket; |
| 323 | |
| 324 | b = ca->buckets + n; |
| 325 | |
| 326 | if (can_invalidate_bucket(ca, b)) |
| 327 | invalidate_one_bucket(ca, b); |
| 328 | |
| 329 | if (++checked >= ca->sb.nbuckets / 2) { |
| 330 | ca->invalidate_needs_gc = 1; |
| 331 | bch_queue_gc(ca->set); |
| 332 | return; |
| 333 | } |
| 334 | } |
| 335 | } |
| 336 | |
| 337 | static void invalidate_buckets(struct cache *ca) |
| 338 | { |
| 339 | if (ca->invalidate_needs_gc) |
| 340 | return; |
| 341 | |
| 342 | switch (CACHE_REPLACEMENT(&ca->sb)) { |
| 343 | case CACHE_REPLACEMENT_LRU: |
| 344 | invalidate_buckets_lru(ca); |
| 345 | break; |
| 346 | case CACHE_REPLACEMENT_FIFO: |
| 347 | invalidate_buckets_fifo(ca); |
| 348 | break; |
| 349 | case CACHE_REPLACEMENT_RANDOM: |
| 350 | invalidate_buckets_random(ca); |
| 351 | break; |
| 352 | } |
Kent Overstreet | 86b26b8 | 2013-04-30 19:14:40 -0700 | [diff] [blame] | 353 | |
| 354 | pr_debug("free %zu/%zu free_inc %zu/%zu unused %zu/%zu", |
| 355 | fifo_used(&ca->free), ca->free.size, |
| 356 | fifo_used(&ca->free_inc), ca->free_inc.size, |
| 357 | fifo_used(&ca->unused), ca->unused.size); |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 358 | } |
| 359 | |
| 360 | #define allocator_wait(ca, cond) \ |
| 361 | do { \ |
Kent Overstreet | 86b26b8 | 2013-04-30 19:14:40 -0700 | [diff] [blame] | 362 | while (1) { \ |
Kent Overstreet | 119ba0f | 2013-04-24 19:01:12 -0700 | [diff] [blame^] | 363 | set_current_state(TASK_INTERRUPTIBLE); \ |
Kent Overstreet | 86b26b8 | 2013-04-30 19:14:40 -0700 | [diff] [blame] | 364 | if (cond) \ |
| 365 | break; \ |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 366 | \ |
| 367 | mutex_unlock(&(ca)->set->bucket_lock); \ |
| 368 | if (test_bit(CACHE_SET_STOPPING_2, &ca->set->flags)) { \ |
Kent Overstreet | 119ba0f | 2013-04-24 19:01:12 -0700 | [diff] [blame^] | 369 | closure_put(&ca->set->cl); \ |
| 370 | return 0; \ |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 371 | } \ |
| 372 | \ |
| 373 | schedule(); \ |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 374 | mutex_lock(&(ca)->set->bucket_lock); \ |
| 375 | } \ |
Kent Overstreet | 119ba0f | 2013-04-24 19:01:12 -0700 | [diff] [blame^] | 376 | __set_current_state(TASK_RUNNING); \ |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 377 | } while (0) |
| 378 | |
Kent Overstreet | 119ba0f | 2013-04-24 19:01:12 -0700 | [diff] [blame^] | 379 | static int bch_allocator_thread(void *arg) |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 380 | { |
Kent Overstreet | 119ba0f | 2013-04-24 19:01:12 -0700 | [diff] [blame^] | 381 | struct cache *ca = arg; |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 382 | |
| 383 | mutex_lock(&ca->set->bucket_lock); |
| 384 | |
| 385 | while (1) { |
Kent Overstreet | 86b26b8 | 2013-04-30 19:14:40 -0700 | [diff] [blame] | 386 | /* |
| 387 | * First, we pull buckets off of the unused and free_inc lists, |
| 388 | * possibly issue discards to them, then we add the bucket to |
| 389 | * the free list: |
| 390 | */ |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 391 | while (1) { |
| 392 | long bucket; |
| 393 | |
| 394 | if ((!atomic_read(&ca->set->prio_blocked) || |
| 395 | !CACHE_SYNC(&ca->set->sb)) && |
| 396 | !fifo_empty(&ca->unused)) |
| 397 | fifo_pop(&ca->unused, bucket); |
| 398 | else if (!fifo_empty(&ca->free_inc)) |
| 399 | fifo_pop(&ca->free_inc, bucket); |
| 400 | else |
| 401 | break; |
| 402 | |
| 403 | allocator_wait(ca, (int) fifo_free(&ca->free) > |
| 404 | atomic_read(&ca->discards_in_flight)); |
| 405 | |
| 406 | if (ca->discard) { |
| 407 | allocator_wait(ca, !list_empty(&ca->discards)); |
| 408 | do_discard(ca, bucket); |
| 409 | } else { |
| 410 | fifo_push(&ca->free, bucket); |
| 411 | closure_wake_up(&ca->set->bucket_wait); |
| 412 | } |
| 413 | } |
| 414 | |
Kent Overstreet | 86b26b8 | 2013-04-30 19:14:40 -0700 | [diff] [blame] | 415 | /* |
| 416 | * We've run out of free buckets, we need to find some buckets |
| 417 | * we can invalidate. First, invalidate them in memory and add |
| 418 | * them to the free_inc list: |
| 419 | */ |
| 420 | |
| 421 | allocator_wait(ca, ca->set->gc_mark_valid && |
| 422 | (ca->need_save_prio > 64 || |
| 423 | !ca->invalidate_needs_gc)); |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 424 | invalidate_buckets(ca); |
| 425 | |
Kent Overstreet | 86b26b8 | 2013-04-30 19:14:40 -0700 | [diff] [blame] | 426 | /* |
| 427 | * Now, we write their new gens to disk so we can start writing |
| 428 | * new stuff to them: |
| 429 | */ |
| 430 | allocator_wait(ca, !atomic_read(&ca->set->prio_blocked)); |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 431 | if (CACHE_SYNC(&ca->set->sb) && |
| 432 | (!fifo_empty(&ca->free_inc) || |
Kent Overstreet | 86b26b8 | 2013-04-30 19:14:40 -0700 | [diff] [blame] | 433 | ca->need_save_prio > 64)) |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 434 | bch_prio_write(ca); |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 435 | } |
| 436 | } |
| 437 | |
| 438 | long bch_bucket_alloc(struct cache *ca, unsigned watermark, struct closure *cl) |
| 439 | { |
| 440 | long r = -1; |
| 441 | again: |
Kent Overstreet | 119ba0f | 2013-04-24 19:01:12 -0700 | [diff] [blame^] | 442 | wake_up_process(ca->alloc_thread); |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 443 | |
| 444 | if (fifo_used(&ca->free) > ca->watermark[watermark] && |
| 445 | fifo_pop(&ca->free, r)) { |
| 446 | struct bucket *b = ca->buckets + r; |
| 447 | #ifdef CONFIG_BCACHE_EDEBUG |
| 448 | size_t iter; |
| 449 | long i; |
| 450 | |
| 451 | for (iter = 0; iter < prio_buckets(ca) * 2; iter++) |
| 452 | BUG_ON(ca->prio_buckets[iter] == (uint64_t) r); |
| 453 | |
| 454 | fifo_for_each(i, &ca->free, iter) |
| 455 | BUG_ON(i == r); |
| 456 | fifo_for_each(i, &ca->free_inc, iter) |
| 457 | BUG_ON(i == r); |
| 458 | fifo_for_each(i, &ca->unused, iter) |
| 459 | BUG_ON(i == r); |
| 460 | #endif |
| 461 | BUG_ON(atomic_read(&b->pin) != 1); |
| 462 | |
| 463 | SET_GC_SECTORS_USED(b, ca->sb.bucket_size); |
| 464 | |
| 465 | if (watermark <= WATERMARK_METADATA) { |
| 466 | SET_GC_MARK(b, GC_MARK_METADATA); |
| 467 | b->prio = BTREE_PRIO; |
| 468 | } else { |
| 469 | SET_GC_MARK(b, GC_MARK_RECLAIMABLE); |
| 470 | b->prio = INITIAL_PRIO; |
| 471 | } |
| 472 | |
| 473 | return r; |
| 474 | } |
| 475 | |
| 476 | pr_debug("alloc failure: blocked %i free %zu free_inc %zu unused %zu", |
| 477 | atomic_read(&ca->set->prio_blocked), fifo_used(&ca->free), |
| 478 | fifo_used(&ca->free_inc), fifo_used(&ca->unused)); |
| 479 | |
| 480 | if (cl) { |
| 481 | closure_wait(&ca->set->bucket_wait, cl); |
| 482 | |
| 483 | if (closure_blocking(cl)) { |
| 484 | mutex_unlock(&ca->set->bucket_lock); |
| 485 | closure_sync(cl); |
| 486 | mutex_lock(&ca->set->bucket_lock); |
| 487 | goto again; |
| 488 | } |
| 489 | } |
| 490 | |
| 491 | return -1; |
| 492 | } |
| 493 | |
| 494 | void bch_bucket_free(struct cache_set *c, struct bkey *k) |
| 495 | { |
| 496 | unsigned i; |
| 497 | |
| 498 | for (i = 0; i < KEY_PTRS(k); i++) { |
| 499 | struct bucket *b = PTR_BUCKET(c, k, i); |
| 500 | |
Kent Overstreet | 86b26b8 | 2013-04-30 19:14:40 -0700 | [diff] [blame] | 501 | SET_GC_MARK(b, GC_MARK_RECLAIMABLE); |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 502 | SET_GC_SECTORS_USED(b, 0); |
| 503 | bch_bucket_add_unused(PTR_CACHE(c, k, i), b); |
| 504 | } |
| 505 | } |
| 506 | |
| 507 | int __bch_bucket_alloc_set(struct cache_set *c, unsigned watermark, |
| 508 | struct bkey *k, int n, struct closure *cl) |
| 509 | { |
| 510 | int i; |
| 511 | |
| 512 | lockdep_assert_held(&c->bucket_lock); |
| 513 | BUG_ON(!n || n > c->caches_loaded || n > 8); |
| 514 | |
| 515 | bkey_init(k); |
| 516 | |
| 517 | /* sort by free space/prio of oldest data in caches */ |
| 518 | |
| 519 | for (i = 0; i < n; i++) { |
| 520 | struct cache *ca = c->cache_by_alloc[i]; |
| 521 | long b = bch_bucket_alloc(ca, watermark, cl); |
| 522 | |
| 523 | if (b == -1) |
| 524 | goto err; |
| 525 | |
| 526 | k->ptr[i] = PTR(ca->buckets[b].gen, |
| 527 | bucket_to_sector(c, b), |
| 528 | ca->sb.nr_this_dev); |
| 529 | |
| 530 | SET_KEY_PTRS(k, i + 1); |
| 531 | } |
| 532 | |
| 533 | return 0; |
| 534 | err: |
| 535 | bch_bucket_free(c, k); |
| 536 | __bkey_put(c, k); |
| 537 | return -1; |
| 538 | } |
| 539 | |
| 540 | int bch_bucket_alloc_set(struct cache_set *c, unsigned watermark, |
| 541 | struct bkey *k, int n, struct closure *cl) |
| 542 | { |
| 543 | int ret; |
| 544 | mutex_lock(&c->bucket_lock); |
| 545 | ret = __bch_bucket_alloc_set(c, watermark, k, n, cl); |
| 546 | mutex_unlock(&c->bucket_lock); |
| 547 | return ret; |
| 548 | } |
| 549 | |
| 550 | /* Init */ |
| 551 | |
Kent Overstreet | 119ba0f | 2013-04-24 19:01:12 -0700 | [diff] [blame^] | 552 | int bch_cache_allocator_start(struct cache *ca) |
| 553 | { |
| 554 | ca->alloc_thread = kthread_create(bch_allocator_thread, |
| 555 | ca, "bcache_allocator"); |
| 556 | if (IS_ERR(ca->alloc_thread)) |
| 557 | return PTR_ERR(ca->alloc_thread); |
| 558 | |
| 559 | closure_get(&ca->set->cl); |
| 560 | wake_up_process(ca->alloc_thread); |
| 561 | |
| 562 | return 0; |
| 563 | } |
| 564 | |
Kent Overstreet | cafe563 | 2013-03-23 16:11:31 -0700 | [diff] [blame] | 565 | void bch_cache_allocator_exit(struct cache *ca) |
| 566 | { |
| 567 | struct discard *d; |
| 568 | |
| 569 | while (!list_empty(&ca->discards)) { |
| 570 | d = list_first_entry(&ca->discards, struct discard, list); |
| 571 | cancel_work_sync(&d->work); |
| 572 | list_del(&d->list); |
| 573 | kfree(d); |
| 574 | } |
| 575 | } |
| 576 | |
| 577 | int bch_cache_allocator_init(struct cache *ca) |
| 578 | { |
| 579 | unsigned i; |
| 580 | |
| 581 | /* |
| 582 | * Reserve: |
| 583 | * Prio/gen writes first |
| 584 | * Then 8 for btree allocations |
| 585 | * Then half for the moving garbage collector |
| 586 | */ |
| 587 | |
| 588 | ca->watermark[WATERMARK_PRIO] = 0; |
| 589 | |
| 590 | ca->watermark[WATERMARK_METADATA] = prio_buckets(ca); |
| 591 | |
| 592 | ca->watermark[WATERMARK_MOVINGGC] = 8 + |
| 593 | ca->watermark[WATERMARK_METADATA]; |
| 594 | |
| 595 | ca->watermark[WATERMARK_NONE] = ca->free.size / 2 + |
| 596 | ca->watermark[WATERMARK_MOVINGGC]; |
| 597 | |
| 598 | for (i = 0; i < MAX_IN_FLIGHT_DISCARDS; i++) { |
| 599 | struct discard *d = kzalloc(sizeof(*d), GFP_KERNEL); |
| 600 | if (!d) |
| 601 | return -ENOMEM; |
| 602 | |
| 603 | d->ca = ca; |
| 604 | INIT_WORK(&d->work, discard_finish); |
| 605 | list_add(&d->list, &ca->discards); |
| 606 | } |
| 607 | |
| 608 | return 0; |
| 609 | } |