/* * Code for working with individual keys, and sorted sets of keys with in a * btree node * * Copyright 2012 Google, Inc. */ #define pr_fmt(fmt) "bcache: %s() " fmt "\n", __func__ #include "util.h" #include "bset.h" #include <linux/console.h> #include <linux/random.h> #include <linux/prefetch.h> #ifdef CONFIG_BCACHE_DEBUG void bch_dump_bset(struct btree_keys *b, struct bset *i, unsigned set) { struct bkey *k, *next; for (k = i->start; k < bset_bkey_last(i); k = next) { next = bkey_next(k); printk(KERN_ERR "block %u key %u/%u: ", set, (unsigned) ((u64 *) k - i->d), i->keys); if (b->ops->key_dump) b->ops->key_dump(b, k); else printk("%llu:%llu\n", KEY_INODE(k), KEY_OFFSET(k)); if (next < bset_bkey_last(i) && bkey_cmp(k, b->ops->is_extents ? &START_KEY(next) : next) > 0) printk(KERN_ERR "Key skipped backwards\n"); } } void bch_dump_bucket(struct btree_keys *b) { unsigned i; console_lock(); for (i = 0; i <= b->nsets; i++) bch_dump_bset(b, b->set[i].data, bset_sector_offset(b, b->set[i].data)); console_unlock(); } int __bch_count_data(struct btree_keys *b) { unsigned ret = 0; struct btree_iter iter; struct bkey *k; if (b->ops->is_extents) for_each_key(b, k, &iter) ret += KEY_SIZE(k); return ret; } void __bch_check_keys(struct btree_keys *b, const char *fmt, ...) { va_list args; struct bkey *k, *p = NULL; struct btree_iter iter; const char *err; for_each_key(b, k, &iter) { if (b->ops->is_extents) { err = "Keys out of order"; if (p && bkey_cmp(&START_KEY(p), &START_KEY(k)) > 0) goto bug; if (bch_ptr_invalid(b, k)) continue; err = "Overlapping keys"; if (p && bkey_cmp(p, &START_KEY(k)) > 0) goto bug; } else { if (bch_ptr_bad(b, k)) continue; err = "Duplicate keys"; if (p && !bkey_cmp(p, k)) goto bug; } p = k; } #if 0 err = "Key larger than btree node key"; if (p && bkey_cmp(p, &b->key) > 0) goto bug; #endif return; bug: bch_dump_bucket(b); va_start(args, fmt); vprintk(fmt, args); va_end(args); panic("bch_check_keys error: %s:\n", err); } static void bch_btree_iter_next_check(struct btree_iter *iter) { struct bkey *k = iter->data->k, *next = bkey_next(k); if (next < iter->data->end && bkey_cmp(k, iter->b->ops->is_extents ? &START_KEY(next) : next) > 0) { bch_dump_bucket(iter->b); panic("Key skipped backwards\n"); } } #else static inline void bch_btree_iter_next_check(struct btree_iter *iter) {} #endif /* Keylists */ int __bch_keylist_realloc(struct keylist *l, unsigned u64s) { size_t oldsize = bch_keylist_nkeys(l); size_t newsize = oldsize + u64s; uint64_t *old_keys = l->keys_p == l->inline_keys ? NULL : l->keys_p; uint64_t *new_keys; newsize = roundup_pow_of_two(newsize); if (newsize <= KEYLIST_INLINE || roundup_pow_of_two(oldsize) == newsize) return 0; new_keys = krealloc(old_keys, sizeof(uint64_t) * newsize, GFP_NOIO); if (!new_keys) return -ENOMEM; if (!old_keys) memcpy(new_keys, l->inline_keys, sizeof(uint64_t) * oldsize); l->keys_p = new_keys; l->top_p = new_keys + oldsize; return 0; } struct bkey *bch_keylist_pop(struct keylist *l) { struct bkey *k = l->keys; if (k == l->top) return NULL; while (bkey_next(k) != l->top) k = bkey_next(k); return l->top = k; } void bch_keylist_pop_front(struct keylist *l) { l->top_p -= bkey_u64s(l->keys); memmove(l->keys, bkey_next(l->keys), bch_keylist_bytes(l)); } /* Key/pointer manipulation */ void bch_bkey_copy_single_ptr(struct bkey *dest, const struct bkey *src, unsigned i) { BUG_ON(i > KEY_PTRS(src)); /* Only copy the header, key, and one pointer. */ memcpy(dest, src, 2 * sizeof(uint64_t)); dest->ptr[0] = src->ptr[i]; SET_KEY_PTRS(dest, 1); /* We didn't copy the checksum so clear that bit. */ SET_KEY_CSUM(dest, 0); } bool __bch_cut_front(const struct bkey *where, struct bkey *k) { unsigned i, len = 0; if (bkey_cmp(where, &START_KEY(k)) <= 0) return false; if (bkey_cmp(where, k) < 0) len = KEY_OFFSET(k) - KEY_OFFSET(where); else bkey_copy_key(k, where); for (i = 0; i < KEY_PTRS(k); i++) SET_PTR_OFFSET(k, i, PTR_OFFSET(k, i) + KEY_SIZE(k) - len); BUG_ON(len > KEY_SIZE(k)); SET_KEY_SIZE(k, len); return true; } bool __bch_cut_back(const struct bkey *where, struct bkey *k) { unsigned len = 0; if (bkey_cmp(where, k) >= 0) return false; BUG_ON(KEY_INODE(where) != KEY_INODE(k)); if (bkey_cmp(where, &START_KEY(k)) > 0) len = KEY_OFFSET(where) - KEY_START(k); bkey_copy_key(k, where); BUG_ON(len > KEY_SIZE(k)); SET_KEY_SIZE(k, len); return true; } /* Auxiliary search trees */ /* 32 bits total: */ #define BKEY_MID_BITS 3 #define BKEY_EXPONENT_BITS 7 #define BKEY_MANTISSA_BITS (32 - BKEY_MID_BITS - BKEY_EXPONENT_BITS) #define BKEY_MANTISSA_MASK ((1 << BKEY_MANTISSA_BITS) - 1) struct bkey_float { unsigned exponent:BKEY_EXPONENT_BITS; unsigned m:BKEY_MID_BITS; unsigned mantissa:BKEY_MANTISSA_BITS; } __packed; /* * BSET_CACHELINE was originally intended to match the hardware cacheline size - * it used to be 64, but I realized the lookup code would touch slightly less * memory if it was 128. * * It definites the number of bytes (in struct bset) per struct bkey_float in * the auxiliar search tree - when we're done searching the bset_float tree we * have this many bytes left that we do a linear search over. * * Since (after level 5) every level of the bset_tree is on a new cacheline, * we're touching one fewer cacheline in the bset tree in exchange for one more * cacheline in the linear search - but the linear search might stop before it * gets to the second cacheline. */ #define BSET_CACHELINE 128 /* Space required for the btree node keys */ static inline size_t btree_keys_bytes(struct btree_keys *b) { return PAGE_SIZE << b->page_order; } static inline size_t btree_keys_cachelines(struct btree_keys *b) { return btree_keys_bytes(b) / BSET_CACHELINE; } /* Space required for the auxiliary search trees */ static inline size_t bset_tree_bytes(struct btree_keys *b) { return btree_keys_cachelines(b) * sizeof(struct bkey_float); } /* Space required for the prev pointers */ static inline size_t bset_prev_bytes(struct btree_keys *b) { return btree_keys_cachelines(b) * sizeof(uint8_t); } /* Memory allocation */ void bch_btree_keys_free(struct btree_keys *b) { struct bset_tree *t = b->set; if (bset_prev_bytes(b) < PAGE_SIZE) kfree(t->prev); else free_pages((unsigned long) t->prev, get_order(bset_prev_bytes(b))); if (bset_tree_bytes(b) < PAGE_SIZE) kfree(t->tree); else free_pages((unsigned long) t->tree, get_order(bset_tree_bytes(b))); free_pages((unsigned long) t->data, b->page_order); t->prev = NULL; t->tree = NULL; t->data = NULL; } EXPORT_SYMBOL(bch_btree_keys_free); int bch_btree_keys_alloc(struct btree_keys *b, unsigned page_order, gfp_t gfp) { struct bset_tree *t = b->set; BUG_ON(t->data); b->page_order = page_order; t->data = (void *) __get_free_pages(gfp, b->page_order); if (!t->data) goto err; t->tree = bset_tree_bytes(b) < PAGE_SIZE ? kmalloc(bset_tree_bytes(b), gfp) : (void *) __get_free_pages(gfp, get_order(bset_tree_bytes(b))); if (!t->tree) goto err; t->prev = bset_prev_bytes(b) < PAGE_SIZE ? kmalloc(bset_prev_bytes(b), gfp) : (void *) __get_free_pages(gfp, get_order(bset_prev_bytes(b))); if (!t->prev) goto err; return 0; err: bch_btree_keys_free(b); return -ENOMEM; } EXPORT_SYMBOL(bch_btree_keys_alloc); void bch_btree_keys_init(struct btree_keys *b, const struct btree_keys_ops *ops, bool *expensive_debug_checks) { unsigned i; b->ops = ops; b->expensive_debug_checks = expensive_debug_checks; b->nsets = 0; b->last_set_unwritten = 0; /* XXX: shouldn't be needed */ for (i = 0; i < MAX_BSETS; i++) b->set[i].size = 0; /* * Second loop starts at 1 because b->keys[0]->data is the memory we * allocated */ for (i = 1; i < MAX_BSETS; i++) b->set[i].data = NULL; } EXPORT_SYMBOL(bch_btree_keys_init); /* Binary tree stuff for auxiliary search trees */ static unsigned inorder_next(unsigned j, unsigned size) { if (j * 2 + 1 < size) { j = j * 2 + 1; while (j * 2 < size) j *= 2; } else j >>= ffz(j) + 1; return j; } static unsigned inorder_prev(unsigned j, unsigned size) { if (j * 2 < size) { j = j * 2; while (j * 2 + 1 < size) j = j * 2 + 1; } else j >>= ffs(j); return j; } /* I have no idea why this code works... and I'm the one who wrote it * * However, I do know what it does: * Given a binary tree constructed in an array (i.e. how you normally implement * a heap), it converts a node in the tree - referenced by array index - to the * index it would have if you did an inorder traversal. * * Also tested for every j, size up to size somewhere around 6 million. * * The binary tree starts at array index 1, not 0 * extra is a function of size: * extra = (size - rounddown_pow_of_two(size - 1)) << 1; */ static unsigned __to_inorder(unsigned j, unsigned size, unsigned extra) { unsigned b = fls(j); unsigned shift = fls(size - 1) - b; j ^= 1U << (b - 1); j <<= 1; j |= 1; j <<= shift; if (j > extra) j -= (j - extra) >> 1; return j; } static unsigned to_inorder(unsigned j, struct bset_tree *t) { return __to_inorder(j, t->size, t->extra); } static unsigned __inorder_to_tree(unsigned j, unsigned size, unsigned extra) { unsigned shift; if (j > extra) j += j - extra; shift = ffs(j); j >>= shift; j |= roundup_pow_of_two(size) >> shift; return j; } static unsigned inorder_to_tree(unsigned j, struct bset_tree *t) { return __inorder_to_tree(j, t->size, t->extra); } #if 0 void inorder_test(void) { unsigned long done = 0; ktime_t start = ktime_get(); for (unsigned size = 2; size < 65536000; size++) { unsigned extra = (size - rounddown_pow_of_two(size - 1)) << 1; unsigned i = 1, j = rounddown_pow_of_two(size - 1); if (!(size % 4096)) printk(KERN_NOTICE "loop %u, %llu per us\n", size, done / ktime_us_delta(ktime_get(), start)); while (1) { if (__inorder_to_tree(i, size, extra) != j) panic("size %10u j %10u i %10u", size, j, i); if (__to_inorder(j, size, extra) != i) panic("size %10u j %10u i %10u", size, j, i); if (j == rounddown_pow_of_two(size) - 1) break; BUG_ON(inorder_prev(inorder_next(j, size), size) != j); j = inorder_next(j, size); i++; } done += size - 1; } } #endif /* * Cacheline/offset <-> bkey pointer arithmetic: * * t->tree is a binary search tree in an array; each node corresponds to a key * in one cacheline in t->set (BSET_CACHELINE bytes). * * This means we don't have to store the full index of the key that a node in * the binary tree points to; to_inorder() gives us the cacheline, and then * bkey_float->m gives us the offset within that cacheline, in units of 8 bytes. * * cacheline_to_bkey() and friends abstract out all the pointer arithmetic to * make this work. * * To construct the bfloat for an arbitrary key we need to know what the key * immediately preceding it is: we have to check if the two keys differ in the * bits we're going to store in bkey_float->mantissa. t->prev[j] stores the size * of the previous key so we can walk backwards to it from t->tree[j]'s key. */ static struct bkey *cacheline_to_bkey(struct bset_tree *t, unsigned cacheline, unsigned offset) { return ((void *) t->data) + cacheline * BSET_CACHELINE + offset * 8; } static unsigned bkey_to_cacheline(struct bset_tree *t, struct bkey *k) { return ((void *) k - (void *) t->data) / BSET_CACHELINE; } static unsigned bkey_to_cacheline_offset(struct bset_tree *t, unsigned cacheline, struct bkey *k) { return (u64 *) k - (u64 *) cacheline_to_bkey(t, cacheline, 0); } static struct bkey *tree_to_bkey(struct bset_tree *t, unsigned j) { return cacheline_to_bkey(t, to_inorder(j, t), t->tree[j].m); } static struct bkey *tree_to_prev_bkey(struct bset_tree *t, unsigned j) { return (void *) (((uint64_t *) tree_to_bkey(t, j)) - t->prev[j]); } /* * For the write set - the one we're currently inserting keys into - we don't * maintain a full search tree, we just keep a simple lookup table in t->prev. */ static struct bkey *table_to_bkey(struct bset_tree *t, unsigned cacheline) { return cacheline_to_bkey(t, cacheline, t->prev[cacheline]); } static inline uint64_t shrd128(uint64_t high, uint64_t low, uint8_t shift) { low >>= shift; low |= (high << 1) << (63U - shift); return low; } static inline unsigned bfloat_mantissa(const struct bkey *k, struct bkey_float *f) { const uint64_t *p = &k->low - (f->exponent >> 6); return shrd128(p[-1], p[0], f->exponent & 63) & BKEY_MANTISSA_MASK; } static void make_bfloat(struct bset_tree *t, unsigned j) { struct bkey_float *f = &t->tree[j]; struct bkey *m = tree_to_bkey(t, j); struct bkey *p = tree_to_prev_bkey(t, j); struct bkey *l = is_power_of_2(j) ? t->data->start : tree_to_prev_bkey(t, j >> ffs(j)); struct bkey *r = is_power_of_2(j + 1) ? bset_bkey_idx(t->data, t->data->keys - bkey_u64s(&t->end)) : tree_to_bkey(t, j >> (ffz(j) + 1)); BUG_ON(m < l || m > r); BUG_ON(bkey_next(p) != m); if (KEY_INODE(l) != KEY_INODE(r)) f->exponent = fls64(KEY_INODE(r) ^ KEY_INODE(l)) + 64; else f->exponent = fls64(r->low ^ l->low); f->exponent = max_t(int, f->exponent - BKEY_MANTISSA_BITS, 0); /* * Setting f->exponent = 127 flags this node as failed, and causes the * lookup code to fall back to comparing against the original key. */ if (bfloat_mantissa(m, f) != bfloat_mantissa(p, f)) f->mantissa = bfloat_mantissa(m, f) - 1; else f->exponent = 127; } static void bset_alloc_tree(struct btree_keys *b, struct bset_tree *t) { if (t != b->set) { unsigned j = roundup(t[-1].size, 64 / sizeof(struct bkey_float)); t->tree = t[-1].tree + j; t->prev = t[-1].prev + j; } while (t < b->set + MAX_BSETS) t++->size = 0; } static void bch_bset_build_unwritten_tree(struct btree_keys *b) { struct bset_tree *t = bset_tree_last(b); BUG_ON(b->last_set_unwritten); b->last_set_unwritten = 1; bset_alloc_tree(b, t); if (t->tree != b->set->tree + btree_keys_cachelines(b)) { t->prev[0] = bkey_to_cacheline_offset(t, 0, t->data->start); t->size = 1; } } void bch_bset_init_next(struct btree_keys *b, struct bset *i, uint64_t magic) { if (i != b->set->data) { b->set[++b->nsets].data = i; i->seq = b->set->data->seq; } else get_random_bytes(&i->seq, sizeof(uint64_t)); i->magic = magic; i->version = 0; i->keys = 0; bch_bset_build_unwritten_tree(b); } EXPORT_SYMBOL(bch_bset_init_next); void bch_bset_build_written_tree(struct btree_keys *b) { struct bset_tree *t = bset_tree_last(b); struct bkey *prev = NULL, *k = t->data->start; unsigned j, cacheline = 1; b->last_set_unwritten = 0; bset_alloc_tree(b, t); t->size = min_t(unsigned, bkey_to_cacheline(t, bset_bkey_last(t->data)), b->set->tree + btree_keys_cachelines(b) - t->tree); if (t->size < 2) { t->size = 0; return; } t->extra = (t->size - rounddown_pow_of_two(t->size - 1)) << 1; /* First we figure out where the first key in each cacheline is */ for (j = inorder_next(0, t->size); j; j = inorder_next(j, t->size)) { while (bkey_to_cacheline(t, k) < cacheline) prev = k, k = bkey_next(k); t->prev[j] = bkey_u64s(prev); t->tree[j].m = bkey_to_cacheline_offset(t, cacheline++, k); } while (bkey_next(k) != bset_bkey_last(t->data)) k = bkey_next(k); t->end = *k; /* Then we build the tree */ for (j = inorder_next(0, t->size); j; j = inorder_next(j, t->size)) make_bfloat(t, j); } EXPORT_SYMBOL(bch_bset_build_written_tree); /* Insert */ void bch_bset_fix_invalidated_key(struct btree_keys *b, struct bkey *k) { struct bset_tree *t; unsigned inorder, j = 1; for (t = b->set; t <= bset_tree_last(b); t++) if (k < bset_bkey_last(t->data)) goto found_set; BUG(); found_set: if (!t->size || !bset_written(b, t)) return; inorder = bkey_to_cacheline(t, k); if (k == t->data->start) goto fix_left; if (bkey_next(k) == bset_bkey_last(t->data)) { t->end = *k; goto fix_right; } j = inorder_to_tree(inorder, t); if (j && j < t->size && k == tree_to_bkey(t, j)) fix_left: do { make_bfloat(t, j); j = j * 2; } while (j < t->size); j = inorder_to_tree(inorder + 1, t); if (j && j < t->size && k == tree_to_prev_bkey(t, j)) fix_right: do { make_bfloat(t, j); j = j * 2 + 1; } while (j < t->size); } EXPORT_SYMBOL(bch_bset_fix_invalidated_key); static void bch_bset_fix_lookup_table(struct btree_keys *b, struct bset_tree *t, struct bkey *k) { unsigned shift = bkey_u64s(k); unsigned j = bkey_to_cacheline(t, k); /* We're getting called from btree_split() or btree_gc, just bail out */ if (!t->size) return; /* k is the key we just inserted; we need to find the entry in the * lookup table for the first key that is strictly greater than k: * it's either k's cacheline or the next one */ while (j < t->size && table_to_bkey(t, j) <= k) j++; /* Adjust all the lookup table entries, and find a new key for any that * have gotten too big */ for (; j < t->size; j++) { t->prev[j] += shift; if (t->prev[j] > 7) { k = table_to_bkey(t, j - 1); while (k < cacheline_to_bkey(t, j, 0)) k = bkey_next(k); t->prev[j] = bkey_to_cacheline_offset(t, j, k); } } if (t->size == b->set->tree + btree_keys_cachelines(b) - t->tree) return; /* Possibly add a new entry to the end of the lookup table */ for (k = table_to_bkey(t, t->size - 1); k != bset_bkey_last(t->data); k = bkey_next(k)) if (t->size == bkey_to_cacheline(t, k)) { t->prev[t->size] = bkey_to_cacheline_offset(t, t->size, k); t->size++; } } /* * Tries to merge l and r: l should be lower than r * Returns true if we were able to merge. If we did merge, l will be the merged * key, r will be untouched. */ bool bch_bkey_try_merge(struct btree_keys *b, struct bkey *l, struct bkey *r) { if (!b->ops->key_merge) return false; /* * Generic header checks * Assumes left and right are in order * Left and right must be exactly aligned */ if (!bch_bkey_equal_header(l, r) || bkey_cmp(l, &START_KEY(r))) return false; return b->ops->key_merge(b, l, r); } EXPORT_SYMBOL(bch_bkey_try_merge); void bch_bset_insert(struct btree_keys *b, struct bkey *where, struct bkey *insert) { struct bset_tree *t = bset_tree_last(b); BUG_ON(!b->last_set_unwritten); BUG_ON(bset_byte_offset(b, t->data) + __set_bytes(t->data, t->data->keys + bkey_u64s(insert)) > PAGE_SIZE << b->page_order); memmove((uint64_t *) where + bkey_u64s(insert), where, (void *) bset_bkey_last(t->data) - (void *) where); t->data->keys += bkey_u64s(insert); bkey_copy(where, insert); bch_bset_fix_lookup_table(b, t, where); } EXPORT_SYMBOL(bch_bset_insert); unsigned bch_btree_insert_key(struct btree_keys *b, struct bkey *k, struct bkey *replace_key) { unsigned status = BTREE_INSERT_STATUS_NO_INSERT; struct bset *i = bset_tree_last(b)->data; struct bkey *m, *prev = NULL; struct btree_iter iter; BUG_ON(b->ops->is_extents && !KEY_SIZE(k)); m = bch_btree_iter_init(b, &iter, b->ops->is_extents ? PRECEDING_KEY(&START_KEY(k)) : PRECEDING_KEY(k)); if (b->ops->insert_fixup(b, k, &iter, replace_key)) return status; status = BTREE_INSERT_STATUS_INSERT; while (m != bset_bkey_last(i) && bkey_cmp(k, b->ops->is_extents ? &START_KEY(m) : m) > 0) prev = m, m = bkey_next(m); /* prev is in the tree, if we merge we're done */ status = BTREE_INSERT_STATUS_BACK_MERGE; if (prev && bch_bkey_try_merge(b, prev, k)) goto merged; #if 0 status = BTREE_INSERT_STATUS_OVERWROTE; if (m != bset_bkey_last(i) && KEY_PTRS(m) == KEY_PTRS(k) && !KEY_SIZE(m)) goto copy; #endif status = BTREE_INSERT_STATUS_FRONT_MERGE; if (m != bset_bkey_last(i) && bch_bkey_try_merge(b, k, m)) goto copy; bch_bset_insert(b, m, k); copy: bkey_copy(m, k); merged: return status; } EXPORT_SYMBOL(bch_btree_insert_key); /* Lookup */ struct bset_search_iter { struct bkey *l, *r; }; static struct bset_search_iter bset_search_write_set(struct bset_tree *t, const struct bkey *search) { unsigned li = 0, ri = t->size; while (li + 1 != ri) { unsigned m = (li + ri) >> 1; if (bkey_cmp(table_to_bkey(t, m), search) > 0) ri = m; else li = m; } return (struct bset_search_iter) { table_to_bkey(t, li), ri < t->size ? table_to_bkey(t, ri) : bset_bkey_last(t->data) }; } static struct bset_search_iter bset_search_tree(struct bset_tree *t, const struct bkey *search) { struct bkey *l, *r; struct bkey_float *f; unsigned inorder, j, n = 1; do { unsigned p = n << 4; p &= ((int) (p - t->size)) >> 31; prefetch(&t->tree[p]); j = n; f = &t->tree[j]; /* * n = (f->mantissa > bfloat_mantissa()) * ? j * 2 * : j * 2 + 1; * * We need to subtract 1 from f->mantissa for the sign bit trick * to work - that's done in make_bfloat() */ if (likely(f->exponent != 127)) n = j * 2 + (((unsigned) (f->mantissa - bfloat_mantissa(search, f))) >> 31); else n = (bkey_cmp(tree_to_bkey(t, j), search) > 0) ? j * 2 : j * 2 + 1; } while (n < t->size); inorder = to_inorder(j, t); /* * n would have been the node we recursed to - the low bit tells us if * we recursed left or recursed right. */ if (n & 1) { l = cacheline_to_bkey(t, inorder, f->m); if (++inorder != t->size) { f = &t->tree[inorder_next(j, t->size)]; r = cacheline_to_bkey(t, inorder, f->m); } else r = bset_bkey_last(t->data); } else { r = cacheline_to_bkey(t, inorder, f->m); if (--inorder) { f = &t->tree[inorder_prev(j, t->size)]; l = cacheline_to_bkey(t, inorder, f->m); } else l = t->data->start; } return (struct bset_search_iter) {l, r}; } struct bkey *__bch_bset_search(struct btree_keys *b, struct bset_tree *t, const struct bkey *search) { struct bset_search_iter i; /* * First, we search for a cacheline, then lastly we do a linear search * within that cacheline. * * To search for the cacheline, there's three different possibilities: * * The set is too small to have a search tree, so we just do a linear * search over the whole set. * * The set is the one we're currently inserting into; keeping a full * auxiliary search tree up to date would be too expensive, so we * use a much simpler lookup table to do a binary search - * bset_search_write_set(). * * Or we use the auxiliary search tree we constructed earlier - * bset_search_tree() */ if (unlikely(!t->size)) { i.l = t->data->start; i.r = bset_bkey_last(t->data); } else if (bset_written(b, t)) { /* * Each node in the auxiliary search tree covers a certain range * of bits, and keys above and below the set it covers might * differ outside those bits - so we have to special case the * start and end - handle that here: */ if (unlikely(bkey_cmp(search, &t->end) >= 0)) return bset_bkey_last(t->data); if (unlikely(bkey_cmp(search, t->data->start) < 0)) return t->data->start; i = bset_search_tree(t, search); } else { BUG_ON(!b->nsets && t->size < bkey_to_cacheline(t, bset_bkey_last(t->data))); i = bset_search_write_set(t, search); } if (btree_keys_expensive_checks(b)) { BUG_ON(bset_written(b, t) && i.l != t->data->start && bkey_cmp(tree_to_prev_bkey(t, inorder_to_tree(bkey_to_cacheline(t, i.l), t)), search) > 0); BUG_ON(i.r != bset_bkey_last(t->data) && bkey_cmp(i.r, search) <= 0); } while (likely(i.l != i.r) && bkey_cmp(i.l, search) <= 0) i.l = bkey_next(i.l); return i.l; } EXPORT_SYMBOL(__bch_bset_search); /* Btree iterator */ typedef bool (btree_iter_cmp_fn)(struct btree_iter_set, struct btree_iter_set); static inline bool btree_iter_cmp(struct btree_iter_set l, struct btree_iter_set r) { return bkey_cmp(l.k, r.k) > 0; } static inline bool btree_iter_end(struct btree_iter *iter) { return !iter->used; } void bch_btree_iter_push(struct btree_iter *iter, struct bkey *k, struct bkey *end) { if (k != end) BUG_ON(!heap_add(iter, ((struct btree_iter_set) { k, end }), btree_iter_cmp)); } static struct bkey *__bch_btree_iter_init(struct btree_keys *b, struct btree_iter *iter, struct bkey *search, struct bset_tree *start) { struct bkey *ret = NULL; iter->size = ARRAY_SIZE(iter->data); iter->used = 0; #ifdef CONFIG_BCACHE_DEBUG iter->b = b; #endif for (; start <= bset_tree_last(b); start++) { ret = bch_bset_search(b, start, search); bch_btree_iter_push(iter, ret, bset_bkey_last(start->data)); } return ret; } struct bkey *bch_btree_iter_init(struct btree_keys *b, struct btree_iter *iter, struct bkey *search) { return __bch_btree_iter_init(b, iter, search, b->set); } EXPORT_SYMBOL(bch_btree_iter_init); static inline struct bkey *__bch_btree_iter_next(struct btree_iter *iter, btree_iter_cmp_fn *cmp) { struct btree_iter_set unused; struct bkey *ret = NULL; if (!btree_iter_end(iter)) { bch_btree_iter_next_check(iter); ret = iter->data->k; iter->data->k = bkey_next(iter->data->k); if (iter->data->k > iter->data->end) { WARN_ONCE(1, "bset was corrupt!\n"); iter->data->k = iter->data->end; } if (iter->data->k == iter->data->end) heap_pop(iter, unused, cmp); else heap_sift(iter, 0, cmp); } return ret; } struct bkey *bch_btree_iter_next(struct btree_iter *iter) { return __bch_btree_iter_next(iter, btree_iter_cmp); } EXPORT_SYMBOL(bch_btree_iter_next); struct bkey *bch_btree_iter_next_filter(struct btree_iter *iter, struct btree_keys *b, ptr_filter_fn fn) { struct bkey *ret; do { ret = bch_btree_iter_next(iter); } while (ret && fn(b, ret)); return ret; } /* Mergesort */ void bch_bset_sort_state_free(struct bset_sort_state *state) { if (state->pool) mempool_destroy(state->pool); } int bch_bset_sort_state_init(struct bset_sort_state *state, unsigned page_order) { spin_lock_init(&state->time.lock); state->page_order = page_order; state->crit_factor = int_sqrt(1 << page_order); state->pool = mempool_create_page_pool(1, page_order); if (!state->pool) return -ENOMEM; return 0; } EXPORT_SYMBOL(bch_bset_sort_state_init); static void btree_mergesort(struct btree_keys *b, struct bset *out, struct btree_iter *iter, bool fixup, bool remove_stale) { int i; struct bkey *k, *last = NULL; BKEY_PADDED(k) tmp; bool (*bad)(struct btree_keys *, const struct bkey *) = remove_stale ? bch_ptr_bad : bch_ptr_invalid; /* Heapify the iterator, using our comparison function */ for (i = iter->used / 2 - 1; i >= 0; --i) heap_sift(iter, i, b->ops->sort_cmp); while (!btree_iter_end(iter)) { if (b->ops->sort_fixup && fixup) k = b->ops->sort_fixup(iter, &tmp.k); else k = NULL; if (!k) k = __bch_btree_iter_next(iter, b->ops->sort_cmp); if (bad(b, k)) continue; if (!last) { last = out->start; bkey_copy(last, k); } else if (!bch_bkey_try_merge(b, last, k)) { last = bkey_next(last); bkey_copy(last, k); } } out->keys = last ? (uint64_t *) bkey_next(last) - out->d : 0; pr_debug("sorted %i keys", out->keys); } static void __btree_sort(struct btree_keys *b, struct btree_iter *iter, unsigned start, unsigned order, bool fixup, struct bset_sort_state *state) { uint64_t start_time; bool used_mempool = false; struct bset *out = (void *) __get_free_pages(__GFP_NOWARN|GFP_NOWAIT, order); if (!out) { struct page *outp; BUG_ON(order > state->page_order); outp = mempool_alloc(state->pool, GFP_NOIO); out = page_address(outp); used_mempool = true; order = state->page_order; } start_time = local_clock(); btree_mergesort(b, out, iter, fixup, false); b->nsets = start; if (!start && order == b->page_order) { /* * Our temporary buffer is the same size as the btree node's * buffer, we can just swap buffers instead of doing a big * memcpy() */ out->magic = b->set->data->magic; out->seq = b->set->data->seq; out->version = b->set->data->version; swap(out, b->set->data); } else { b->set[start].data->keys = out->keys; memcpy(b->set[start].data->start, out->start, (void *) bset_bkey_last(out) - (void *) out->start); } if (used_mempool) mempool_free(virt_to_page(out), state->pool); else free_pages((unsigned long) out, order); bch_bset_build_written_tree(b); if (!start) bch_time_stats_update(&state->time, start_time); } void bch_btree_sort_partial(struct btree_keys *b, unsigned start, struct bset_sort_state *state) { size_t order = b->page_order, keys = 0; struct btree_iter iter; int oldsize = bch_count_data(b); __bch_btree_iter_init(b, &iter, NULL, &b->set[start]); if (start) { unsigned i; for (i = start; i <= b->nsets; i++) keys += b->set[i].data->keys; order = get_order(__set_bytes(b->set->data, keys)); } __btree_sort(b, &iter, start, order, false, state); EBUG_ON(oldsize >= 0 && bch_count_data(b) != oldsize); } EXPORT_SYMBOL(bch_btree_sort_partial); void bch_btree_sort_and_fix_extents(struct btree_keys *b, struct btree_iter *iter, struct bset_sort_state *state) { __btree_sort(b, iter, 0, b->page_order, true, state); } void bch_btree_sort_into(struct btree_keys *b, struct btree_keys *new, struct bset_sort_state *state) { uint64_t start_time = local_clock(); struct btree_iter iter; bch_btree_iter_init(b, &iter, NULL); btree_mergesort(b, new->set->data, &iter, false, true); bch_time_stats_update(&state->time, start_time); new->set->size = 0; // XXX: why? } #define SORT_CRIT (4096 / sizeof(uint64_t)) void bch_btree_sort_lazy(struct btree_keys *b, struct bset_sort_state *state) { unsigned crit = SORT_CRIT; int i; /* Don't sort if nothing to do */ if (!b->nsets) goto out; for (i = b->nsets - 1; i >= 0; --i) { crit *= state->crit_factor; if (b->set[i].data->keys < crit) { bch_btree_sort_partial(b, i, state); return; } } /* Sort if we'd overflow */ if (b->nsets + 1 == MAX_BSETS) { bch_btree_sort(b, state); return; } out: bch_bset_build_written_tree(b); } EXPORT_SYMBOL(bch_btree_sort_lazy); void bch_btree_keys_stats(struct btree_keys *b, struct bset_stats *stats) { unsigned i; for (i = 0; i <= b->nsets; i++) { struct bset_tree *t = &b->set[i]; size_t bytes = t->data->keys * sizeof(uint64_t); size_t j; if (bset_written(b, t)) { stats->sets_written++; stats->bytes_written += bytes; stats->floats += t->size - 1; for (j = 1; j < t->size; j++) if (t->tree[j].exponent == 127) stats->failed++; } else { stats->sets_unwritten++; stats->bytes_unwritten += bytes; } } }