// SPDX-License-Identifier: GPL-2.0/* * Primary bucket allocation code * * Copyright 2012 Google, Inc. * * Allocation in bcache is done in terms of buckets: * * Each bucket has associated an 8 bit gen; this gen corresponds to the gen in * btree pointers - they must match for the pointer to be considered valid. * * Thus (assuming a bucket has no dirty data or metadata in it) we can reuse a * bucket simply by incrementing its gen. * * The gens (along with the priorities; it's really the gens are important but * the code is named as if it's the priorities) are written in an arbitrary list * of buckets on disk, with a pointer to them in the journal header. * * When we invalidate a bucket, we have to write its new gen to disk and wait * for that write to complete before we use it - otherwise after a crash we * could have pointers that appeared to be good but pointed to data that had * been overwritten. * * Since the gens and priorities are all stored contiguously on disk, we can * batch this up: We fill up the free_inc list with freshly invalidated buckets, * call prio_write(), and when prio_write() finishes we pull buckets off the * free_inc list and optionally discard them. * * free_inc isn't the only freelist - if it was, we'd often to sleep while * priorities and gens were being written before we could allocate. c->free is a * smaller freelist, and buckets on that list are always ready to be used. * * If we've got discards enabled, that happens when a bucket moves from the * free_inc list to the free list. * * There is another freelist, because sometimes we have buckets that we know * have nothing pointing into them - these we can reuse without waiting for * priorities to be rewritten. These come from freed btree nodes and buckets * that garbage collection discovered no longer had valid keys pointing into * them (because they were overwritten). That's the unused list - buckets on the * unused list move to the free list, optionally being discarded in the process. * * It's also important to ensure that gens don't wrap around - with respect to * either the oldest gen in the btree or the gen on disk. This is quite * difficult to do in practice, but we explicitly guard against it anyways - if * a bucket is in danger of wrapping around we simply skip invalidating it that * time around, and we garbage collect or rewrite the priorities sooner than we * would have otherwise. * * bch_bucket_alloc() allocates a single bucket from a specific cache. * * bch_bucket_alloc_set() allocates one bucket from different caches * out of a cache set. * * free_some_buckets() drives all the processes described above. It's called * from bch_bucket_alloc() and a few other places that need to make sure free * buckets are ready. * * invalidate_buckets_(lru|fifo)() find buckets that are available to be * invalidated, and then invalidate them and stick them on the free_inc list - * in either lru or fifo order. */ #include "bcache.h"#include "btree.h" #include <linux/blkdev.h>#include <linux/kthread.h>#include <linux/random.h>#include <trace/events/bcache.h> #define MAX_OPEN_BUCKETS 128 /* Bucket heap / gen */ uint8_t bch_inc_gen(struct cache *ca, struct bucket *b){ uint8_t ret = ++b->gen; ca->set->need_gc = max(ca->set->need_gc, bucket_gc_gen(b)); WARN_ON_ONCE(ca->set->need_gc > BUCKET_GC_GEN_MAX); return ret;} void bch_rescale_priorities(struct cache_set *c, int sectors){ struct cache *ca; struct bucket *b; unsigned long next = c->nbuckets * c->cache->sb.bucket_size / 1024; int r; atomic_sub(sectors, &c->rescale); do { r = atomic_read(&c->rescale); if (r >= 0) return; } while (atomic_cmpxchg(&c->rescale, r, r + next) != r); mutex_lock(&c->bucket_lock); c->min_prio = USHRT_MAX; ca = c->cache; for_each_bucket(b, ca) if (b->prio && b->prio != BTREE_PRIO && !atomic_read(&b->pin)) { b->prio--; c->min_prio = min(c->min_prio, b->prio); } mutex_unlock(&c->bucket_lock);} /* * Background allocation thread: scans for buckets to be invalidated, * invalidates them, rewrites prios/gens (marking them as invalidated on disk), * then optionally issues discard commands to the newly free buckets, then puts * them on the various freelists. */ static inline bool can_inc_bucket_gen(struct bucket *b){ return bucket_gc_gen(b) < BUCKET_GC_GEN_MAX;} bool bch_can_invalidate_bucket(struct cache *ca, struct bucket *b){ BUG_ON(!ca->set->gc_mark_valid); return (!GC_MARK(b) || GC_MARK(b) == GC_MARK_RECLAIMABLE) && !atomic_read(&b->pin) && can_inc_bucket_gen(b);} void __bch_invalidate_one_bucket(struct cache *ca, struct bucket *b){ lockdep_assert_held(&ca->set->bucket_lock); BUG_ON(GC_MARK(b) && GC_MARK(b) != GC_MARK_RECLAIMABLE); if (GC_SECTORS_USED(b)) trace_bcache_invalidate(ca, b - ca->buckets); bch_inc_gen(ca, b); b->prio = INITIAL_PRIO; atomic_inc(&b->pin);} static void bch_invalidate_one_bucket(struct cache *ca, struct bucket *b){ __bch_invalidate_one_bucket(ca, b); fifo_push(&ca->free_inc, b - ca->buckets);} /* * Determines what order we're going to reuse buckets, smallest bucket_prio() * first: we also take into account the number of sectors of live data in that * bucket, and in order for that multiply to make sense we have to scale bucket * * Thus, we scale the bucket priorities so that the bucket with the smallest * prio is worth 1/8th of what INITIAL_PRIO is worth. */ #define bucket_prio(b) \({ \ unsigned int min_prio = (INITIAL_PRIO - ca->set->min_prio) / 8; \ \ (b->prio - ca->set->min_prio + min_prio) * GC_SECTORS_USED(b); \}) #define bucket_max_cmp(l, r) (bucket_prio(l) < bucket_prio(r))#define bucket_min_cmp(l, r) (bucket_prio(l) > bucket_prio(r)) static void invalidate_buckets_lru(struct cache *ca){ struct bucket *b; ssize_t i; ca->heap.used = 0; for_each_bucket(b, ca) { if (!bch_can_invalidate_bucket(ca, b)) continue; if (!heap_full(&ca->heap)) heap_add(&ca->heap, b, bucket_max_cmp); else if (bucket_max_cmp(b, heap_peek(&ca->heap))) { ca->heap.data[0] = b; heap_sift(&ca->heap, 0, bucket_max_cmp); } } for (i = ca->heap.used / 2 - 1; i >= 0; --i) heap_sift(&ca->heap, i, bucket_min_cmp); while (!fifo_full(&ca->free_inc)) { if (!heap_pop(&ca->heap, b, bucket_min_cmp)) { /* * We don't want to be calling invalidate_buckets() * multiple times when it can't do anything */ ca->invalidate_needs_gc = 1; wake_up_gc(ca->set); return; } bch_invalidate_one_bucket(ca, b); }} static void invalidate_buckets_fifo(struct cache *ca){ struct bucket *b; size_t checked = 0; while (!fifo_full(&ca->free_inc)) { if (ca->fifo_last_bucket < ca->sb.first_bucket || ca->fifo_last_bucket >= ca->sb.nbuckets) ca->fifo_last_bucket = ca->sb.first_bucket; b = ca->buckets + ca->fifo_last_bucket++; if (bch_can_invalidate_bucket(ca, b)) bch_invalidate_one_bucket(ca, b); if (++checked >= ca->sb.nbuckets) { ca->invalidate_needs_gc = 1; wake_up_gc(ca->set); return; } }} static void invalidate_buckets_random(struct cache *ca){ struct bucket *b; size_t checked = 0; while (!fifo_full(&ca->free_inc)) { size_t n; get_random_bytes(&n, sizeof(n)); n %= (size_t) (ca->sb.nbuckets - ca->sb.first_bucket); n += ca->sb.first_bucket; b = ca->buckets + n; if (bch_can_invalidate_bucket(ca, b)) bch_invalidate_one_bucket(ca, b); if (++checked >= ca->sb.nbuckets / 2) { ca->invalidate_needs_gc = 1; wake_up_gc(ca->set); return; } }} static void invalidate_buckets(struct cache *ca){ BUG_ON(ca->invalidate_needs_gc); switch (CACHE_REPLACEMENT(&ca->sb)) { case CACHE_REPLACEMENT_LRU: invalidate_buckets_lru(ca); break; case CACHE_REPLACEMENT_FIFO: invalidate_buckets_fifo(ca); break; case CACHE_REPLACEMENT_RANDOM: invalidate_buckets_random(ca); break; }} #define allocator_wait(ca, cond) \do { \ while (1) { \ set_current_state(TASK_INTERRUPTIBLE); \ if (cond) \ break; \ \ mutex_unlock(&(ca)->set->bucket_lock); \ if (kthread_should_stop() || \ test_bit(CACHE_SET_IO_DISABLE, &ca->set->flags)) { \ set_current_state(TASK_RUNNING); \ goto out; \ } \ \ schedule(); \ mutex_lock(&(ca)->set->bucket_lock); \ } \ __set_current_state(TASK_RUNNING); \} while (0) static int bch_allocator_push(struct cache *ca, long bucket){ unsigned int i; /* Prios/gens are actually the most important reserve */ if (fifo_push(&ca->free[RESERVE_PRIO], bucket)) return true; for (i = 0; i < RESERVE_NR; i++) if (fifo_push(&ca->free[i], bucket)) return true; return false;} static int bch_allocator_thread(void *arg){ struct cache *ca = arg; mutex_lock(&ca->set->bucket_lock); while (1) { /* * First, we pull buckets off of the unused and free_inc lists, * possibly issue discards to them, then we add the bucket to * the free list: */ while (1) { long bucket; if (!fifo_pop(&ca->free_inc, bucket)) break; if (ca->discard) { mutex_unlock(&ca->set->bucket_lock); blkdev_issue_discard(ca->bdev, bucket_to_sector(ca->set, bucket), ca->sb.bucket_size, GFP_KERNEL, 0); mutex_lock(&ca->set->bucket_lock); } allocator_wait(ca, bch_allocator_push(ca, bucket)); wake_up(&ca->set->btree_cache_wait); wake_up(&ca->set->bucket_wait); } /* * We've run out of free buckets, we need to find some buckets * we can invalidate. First, invalidate them in memory and add * them to the free_inc list: */ retry_invalidate: allocator_wait(ca, ca->set->gc_mark_valid && !ca->invalidate_needs_gc); invalidate_buckets(ca); /* * Now, we write their new gens to disk so we can start writing * new stuff to them: */ allocator_wait(ca, !atomic_read(&ca->set->prio_blocked)); if (CACHE_SYNC(&ca->sb)) { /* * This could deadlock if an allocation with a btree * node locked ever blocked - having the btree node * locked would block garbage collection, but here we're * waiting on garbage collection before we invalidate * and free anything. * * But this should be safe since the btree code always * uses btree_check_reserve() before allocating now, and * if it fails it blocks without btree nodes locked. */ if (!fifo_full(&ca->free_inc)) goto retry_invalidate; if (bch_prio_write(ca, false) < 0) { ca->invalidate_needs_gc = 1; wake_up_gc(ca->set); } } }out: wait_for_kthread_stop(); return 0;} /* Allocation */ long bch_bucket_alloc(struct cache *ca, unsigned int reserve, bool wait){ DEFINE_WAIT(w); struct bucket *b; long r; /* No allocation if CACHE_SET_IO_DISABLE bit is set */ if (unlikely(test_bit(CACHE_SET_IO_DISABLE, &ca->set->flags))) return -1; /* fastpath */ if (fifo_pop(&ca->free[RESERVE_NONE], r) || fifo_pop(&ca->free[reserve], r)) goto out; if (!wait) { trace_bcache_alloc_fail(ca, reserve); return -1; } do { prepare_to_wait(&ca->set->bucket_wait, &w, TASK_UNINTERRUPTIBLE); mutex_unlock(&ca->set->bucket_lock); schedule(); mutex_lock(&ca->set->bucket_lock); } while (!fifo_pop(&ca->free[RESERVE_NONE], r) && !fifo_pop(&ca->free[reserve], r)); finish_wait(&ca->set->bucket_wait, &w);out: if (ca->alloc_thread) wake_up_process(ca->alloc_thread); trace_bcache_alloc(ca, reserve); if (expensive_debug_checks(ca->set)) { size_t iter; long i; unsigned int j; for (iter = 0; iter < prio_buckets(ca) * 2; iter++) BUG_ON(ca->prio_buckets[iter] == (uint64_t) r); for (j = 0; j < RESERVE_NR; j++) fifo_for_each(i, &ca->free[j], iter) BUG_ON(i == r); fifo_for_each(i, &ca->free_inc, iter) BUG_ON(i == r); } b = ca->buckets + r; BUG_ON(atomic_read(&b->pin) != 1); SET_GC_SECTORS_USED(b, ca->sb.bucket_size); if (reserve <= RESERVE_PRIO) { SET_GC_MARK(b, GC_MARK_METADATA); SET_GC_MOVE(b, 0); b->prio = BTREE_PRIO; } else { SET_GC_MARK(b, GC_MARK_RECLAIMABLE); SET_GC_MOVE(b, 0); b->prio = INITIAL_PRIO; } if (ca->set->avail_nbuckets > 0) { ca->set->avail_nbuckets--; bch_update_bucket_in_use(ca->set, &ca->set->gc_stats); } return r;} void __bch_bucket_free(struct cache *ca, struct bucket *b){ SET_GC_MARK(b, 0); SET_GC_SECTORS_USED(b, 0); if (ca->set->avail_nbuckets < ca->set->nbuckets) { ca->set->avail_nbuckets++; bch_update_bucket_in_use(ca->set, &ca->set->gc_stats); }} void bch_bucket_free(struct cache_set *c, struct bkey *k){ unsigned int i; for (i = 0; i < KEY_PTRS(k); i++) __bch_bucket_free(c->cache, PTR_BUCKET(c, k, i));} int __bch_bucket_alloc_set(struct cache_set *c, unsigned int reserve, struct bkey *k, bool wait){ struct cache *ca; long b; /* No allocation if CACHE_SET_IO_DISABLE bit is set */ if (unlikely(test_bit(CACHE_SET_IO_DISABLE, &c->flags))) return -1; lockdep_assert_held(&c->bucket_lock); bkey_init(k);Lines 1–500 of 736. 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// SPDX-License-Identifier: GPL-2.0 /* * Primary bucket allocation code * * Copyright 2012 Google, Inc. * * Allocation in bcache is done in terms of buckets: * * Each bucket has associated an 8 bit gen; this gen corresponds to the gen in * btree pointers - they must match for the pointer to be considered valid. * * Thus (assuming a bucket has no dirty data or metadata in it) we can reuse a * bucket simply by incrementing its gen. * * The gens (along with the priorities; it's really the gens are important but * the code is named as if it's the priorities) are written in an arbitrary list * of buckets on disk, with a pointer to them in the journal header. * * When we invalidate a bucket, we have to write its new gen to disk and wait * for that write to complete before we use it - otherwise after a crash we * could have pointers that appeared to be good but pointed to data that had * been overwritten. * * Since the gens and priorities are all stored contiguously on disk, we can * batch this up: We fill up the free_inc list with freshly invalidated buckets, * call prio_write(), and when prio_write() finishes we pull buckets off the * free_inc list and optionally discard them. * * free_inc isn't the only freelist - if it was, we'd often to sleep while * priorities and gens were being written before we could allocate. c->free is a * smaller freelist, and buckets on that list are always ready to be used. * * If we've got discards enabled, that happens when a bucket moves from the * free_inc list to the free list. * * There is another freelist, because sometimes we have buckets that we know * have nothing pointing into them - these we can reuse without waiting for * priorities to be rewritten. These come from freed btree nodes and buckets * that garbage collection discovered no longer had valid keys pointing into * them (because they were overwritten). That's the unused list - buckets on the * unused list move to the free list, optionally being discarded in the process. * * It's also important to ensure that gens don't wrap around - with respect to * either the oldest gen in the btree or the gen on disk. This is quite * difficult to do in practice, but we explicitly guard against it anyways - if * a bucket is in danger of wrapping around we simply skip invalidating it that * time around, and we garbage collect or rewrite the priorities sooner than we * would have otherwise. * * bch_bucket_alloc() allocates a single bucket from a specific cache. * * bch_bucket_alloc_set() allocates one bucket from different caches * out of a cache set. * * free_some_buckets() drives all the processes described above. It's called * from bch_bucket_alloc() and a few other places that need to make sure free * buckets are ready. * * invalidate_buckets_(lru|fifo)() find buckets that are available to be * invalidated, and then invalidate them and stick them on the free_inc list - * in either lru or fifo order. */ #include "bcache.h" #include "btree.h" #include <linux/blkdev.h> #include <linux/kthread.h> #include <linux/random.h> #include <trace/events/bcache.h> #define MAX_OPEN_BUCKETS 128 /* Bucket heap / gen */ uint8_t bch_inc_gen(struct cache *ca, struct bucket *b) { uint8_t ret = ++b->gen; ca->set->need_gc = max(ca->set->need_gc, bucket_gc_gen(b)); WARN_ON_ONCE(ca->set->need_gc > BUCKET_GC_GEN_MAX); return ret; } void bch_rescale_priorities(struct cache_set *c, int sectors) { struct cache *ca; struct bucket *b; unsigned long next = c->nbuckets * c->cache->sb.bucket_size / 1024; int r; atomic_sub(sectors, &c->rescale); do { r = atomic_read(&c->rescale); if (r >= 0) return; } while (atomic_cmpxchg(&c->rescale, r, r + next) != r); mutex_lock(&c->bucket_lock); c->min_prio = USHRT_MAX; ca = c->cache; for_each_bucket(b, ca) if (b->prio && b->prio != BTREE_PRIO && !atomic_read(&b->pin)) { b->prio--; c->min_prio = min(c->min_prio, b->prio); } mutex_unlock(&c->bucket_lock); } /* * Background allocation thread: scans for buckets to be invalidated, * invalidates them, rewrites prios/gens (marking them as invalidated on disk), * then optionally issues discard commands to the newly free buckets, then puts * them on the various freelists. */ static inline bool can_inc_bucket_gen(struct bucket *b) { return bucket_gc_gen(b) < BUCKET_GC_GEN_MAX; } bool bch_can_invalidate_bucket(struct cache *ca, struct bucket *b) { BUG_ON(!ca->set->gc_mark_valid); return (!GC_MARK(b) || GC_MARK(b) == GC_MARK_RECLAIMABLE) && !atomic_read(&b->pin) && can_inc_bucket_gen(b); } void __bch_invalidate_one_bucket(struct cache *ca, struct bucket *b) { lockdep_assert_held(&ca->set->bucket_lock); BUG_ON(GC_MARK(b) && GC_MARK(b) != GC_MARK_RECLAIMABLE); if (GC_SECTORS_USED(b)) trace_bcache_invalidate(ca, b - ca->buckets); bch_inc_gen(ca, b); b->prio = INITIAL_PRIO; atomic_inc(&b->pin); } static void bch_invalidate_one_bucket(struct cache *ca, struct bucket *b) { __bch_invalidate_one_bucket(ca, b); fifo_push(&ca->free_inc, b - ca->buckets); } /* * Determines what order we're going to reuse buckets, smallest bucket_prio() * first: we also take into account the number of sectors of live data in that * bucket, and in order for that multiply to make sense we have to scale bucket * * Thus, we scale the bucket priorities so that the bucket with the smallest * prio is worth 1/8th of what INITIAL_PRIO is worth. */ #define bucket_prio(b) \ ({ \ unsigned int min_prio = (INITIAL_PRIO - ca->set->min_prio) / 8; \ \ (b->prio - ca->set->min_prio + min_prio) * GC_SECTORS_USED(b); \ }) #define bucket_max_cmp(l, r) (bucket_prio(l) < bucket_prio(r)) #define bucket_min_cmp(l, r) (bucket_prio(l) > bucket_prio(r)) static void invalidate_buckets_lru(struct cache *ca) { struct bucket *b; ssize_t i; ca->heap.used = 0; for_each_bucket(b, ca) { if (!bch_can_invalidate_bucket(ca, b)) continue; if (!heap_full(&ca->heap)) heap_add(&ca->heap, b, bucket_max_cmp); else if (bucket_max_cmp(b, heap_peek(&ca->heap))) { ca->heap.data[0] = b; heap_sift(&ca->heap, 0, bucket_max_cmp); } } for (i = ca->heap.used / 2 - 1; i >= 0; --i) heap_sift(&ca->heap, i, bucket_min_cmp); while (!fifo_full(&ca->free_inc)) { if (!heap_pop(&ca->heap, b, bucket_min_cmp)) { /* * We don't want to be calling invalidate_buckets() * multiple times when it can't do anything */ ca->invalidate_needs_gc = 1; wake_up_gc(ca->set); return; } bch_invalidate_one_bucket(ca, b); } } static void invalidate_buckets_fifo(struct cache *ca) { struct bucket *b; size_t checked = 0; while (!fifo_full(&ca->free_inc)) { if (ca->fifo_last_bucket < ca->sb.first_bucket || ca->fifo_last_bucket >= ca->sb.nbuckets) ca->fifo_last_bucket = ca->sb.first_bucket; b = ca->buckets + ca->fifo_last_bucket++; if (bch_can_invalidate_bucket(ca, b)) bch_invalidate_one_bucket(ca, b); if (++checked >= ca->sb.nbuckets) { ca->invalidate_needs_gc = 1; wake_up_gc(ca->set); return; } } } static void invalidate_buckets_random(struct cache *ca) { struct bucket *b; size_t checked = 0; while (!fifo_full(&ca->free_inc)) { size_t n; get_random_bytes(&n, sizeof(n)); n %= (size_t) (ca->sb.nbuckets - ca->sb.first_bucket); n += ca->sb.first_bucket; b = ca->buckets + n; if (bch_can_invalidate_bucket(ca, b)) bch_invalidate_one_bucket(ca, b); if (++checked >= ca->sb.nbuckets / 2) { ca->invalidate_needs_gc = 1; wake_up_gc(ca->set); return; } } } static void invalidate_buckets(struct cache *ca) { BUG_ON(ca->invalidate_needs_gc); switch (CACHE_REPLACEMENT(&ca->sb)) { case CACHE_REPLACEMENT_LRU: invalidate_buckets_lru(ca); break; case CACHE_REPLACEMENT_FIFO: invalidate_buckets_fifo(ca); break; case CACHE_REPLACEMENT_RANDOM: invalidate_buckets_random(ca); break; } } #define allocator_wait(ca, cond) \ do { \ while (1) { \ set_current_state(TASK_INTERRUPTIBLE); \ if (cond) \ break; \ \ mutex_unlock(&(ca)->set->bucket_lock); \ if (kthread_should_stop() || \ test_bit(CACHE_SET_IO_DISABLE, &ca->set->flags)) { \ set_current_state(TASK_RUNNING); \ goto out; \ } \ \ schedule(); \ mutex_lock(&(ca)->set->bucket_lock); \ } \ __set_current_state(TASK_RUNNING); \ } while (0) static int bch_allocator_push(struct cache *ca, long bucket) { unsigned int i; /* Prios/gens are actually the most important reserve */ if (fifo_push(&ca->free[RESERVE_PRIO], bucket)) return true; for (i = 0; i < RESERVE_NR; i++) if (fifo_push(&ca->free[i], bucket)) return true; return false; } static int bch_allocator_thread(void *arg) { struct cache *ca = arg; mutex_lock(&ca->set->bucket_lock); while (1) { /* * First, we pull buckets off of the unused and free_inc lists, * possibly issue discards to them, then we add the bucket to * the free list: */ while (1) { long bucket; if (!fifo_pop(&ca->free_inc, bucket)) break; if (ca->discard) { mutex_unlock(&ca->set->bucket_lock); blkdev_issue_discard(ca->bdev, bucket_to_sector(ca->set, bucket), ca->sb.bucket_size, GFP_KERNEL, 0); mutex_lock(&ca->set->bucket_lock); } allocator_wait(ca, bch_allocator_push(ca, bucket)); wake_up(&ca->set->btree_cache_wait); wake_up(&ca->set->bucket_wait); } /* * We've run out of free buckets, we need to find some buckets * we can invalidate. First, invalidate them in memory and add * them to the free_inc list: */ retry_invalidate: allocator_wait(ca, ca->set->gc_mark_valid && !ca->invalidate_needs_gc); invalidate_buckets(ca); /* * Now, we write their new gens to disk so we can start writing * new stuff to them: */ allocator_wait(ca, !atomic_read(&ca->set->prio_blocked)); if (CACHE_SYNC(&ca->sb)) { /* * This could deadlock if an allocation with a btree * node locked ever blocked - having the btree node * locked would block garbage collection, but here we're * waiting on garbage collection before we invalidate * and free anything. * * But this should be safe since the btree code always * uses btree_check_reserve() before allocating now, and * if it fails it blocks without btree nodes locked. */ if (!fifo_full(&ca->free_inc)) goto retry_invalidate; if (bch_prio_write(ca, false) < 0) { ca->invalidate_needs_gc = 1; wake_up_gc(ca->set); } } } out: wait_for_kthread_stop(); return 0; } /* Allocation */ long bch_bucket_alloc(struct cache *ca, unsigned int reserve, bool wait) { DEFINE_WAIT(w); struct bucket *b; long r; /* No allocation if CACHE_SET_IO_DISABLE bit is set */ if (unlikely(test_bit(CACHE_SET_IO_DISABLE, &ca->set->flags))) return -1; /* fastpath */ if (fifo_pop(&ca->free[RESERVE_NONE], r) || fifo_pop(&ca->free[reserve], r)) goto out; if (!wait) { trace_bcache_alloc_fail(ca, reserve); return -1; } do { prepare_to_wait(&ca->set->bucket_wait, &w, TASK_UNINTERRUPTIBLE); mutex_unlock(&ca->set->bucket_lock); schedule(); mutex_lock(&ca->set->bucket_lock); } while (!fifo_pop(&ca->free[RESERVE_NONE], r) && !fifo_pop(&ca->free[reserve], r)); finish_wait(&ca->set->bucket_wait, &w); out: if (ca->alloc_thread) wake_up_process(ca->alloc_thread); trace_bcache_alloc(ca, reserve); if (expensive_debug_checks(ca->set)) { size_t iter; long i; unsigned int j; for (iter = 0; iter < prio_buckets(ca) * 2; iter++) BUG_ON(ca->prio_buckets[iter] == (uint64_t) r); for (j = 0; j < RESERVE_NR; j++) fifo_for_each(i, &ca->free[j], iter) BUG_ON(i == r); fifo_for_each(i, &ca->free_inc, iter) BUG_ON(i == r); } b = ca->buckets + r; BUG_ON(atomic_read(&b->pin) != 1); SET_GC_SECTORS_USED(b, ca->sb.bucket_size); if (reserve <= RESERVE_PRIO) { SET_GC_MARK(b, GC_MARK_METADATA); SET_GC_MOVE(b, 0); b->prio = BTREE_PRIO; } else { SET_GC_MARK(b, GC_MARK_RECLAIMABLE); SET_GC_MOVE(b, 0); b->prio = INITIAL_PRIO; } if (ca->set->avail_nbuckets > 0) { ca->set->avail_nbuckets--; bch_update_bucket_in_use(ca->set, &ca->set->gc_stats); } return r; } void __bch_bucket_free(struct cache *ca, struct bucket *b) { SET_GC_MARK(b, 0); SET_GC_SECTORS_USED(b, 0); if (ca->set->avail_nbuckets < ca->set->nbuckets) { ca->set->avail_nbuckets++; bch_update_bucket_in_use(ca->set, &ca->set->gc_stats); } } void bch_bucket_free(struct cache_set *c, struct bkey *k) { unsigned int i; for (i = 0; i < KEY_PTRS(k); i++) __bch_bucket_free(c->cache, PTR_BUCKET(c, k, i)); } int __bch_bucket_alloc_set(struct cache_set *c, unsigned int reserve, struct bkey *k, bool wait) { struct cache *ca; long b; /* No allocation if CACHE_SET_IO_DISABLE bit is set */ if (unlikely(test_bit(CACHE_SET_IO_DISABLE, &c->flags))) return -1; lockdep_assert_held(&c->bucket_lock); bkey_init(k);