diff options
Diffstat (limited to 'drivers/md/bcache/bset.c')
| -rw-r--r-- | drivers/md/bcache/bset.c | 1417 |
1 files changed, 1417 insertions, 0 deletions
diff --git a/drivers/md/bcache/bset.c b/drivers/md/bcache/bset.c new file mode 100644 index 000000000..ec48cf86c --- /dev/null +++ b/drivers/md/bcache/bset.c @@ -0,0 +1,1417 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * 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/sched/clock.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 int set) +{ + struct bkey *k, *next; + + for (k = i->start; k < bset_bkey_last(i); k = next) { + next = bkey_next(k); + + pr_err("block %u key %u/%u: ", set, + (unsigned int) ((u64 *) k - i->d), i->keys); + + if (b->ops->key_dump) + b->ops->key_dump(b, k); + else + pr_err("%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) + pr_err("Key skipped backwards\n"); + } +} + +void bch_dump_bucket(struct btree_keys *b) +{ + unsigned int 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 int 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 int 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 int 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 int 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 int 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 int exponent:BKEY_EXPONENT_BITS; + unsigned int m:BKEY_MID_BITS; + unsigned int 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 int 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_COMP|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 int 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 */ + +/* + * return array index next to j when does in-order traverse + * of a binary tree which is stored in a linear array + */ +static unsigned int inorder_next(unsigned int j, unsigned int size) +{ + if (j * 2 + 1 < size) { + j = j * 2 + 1; + + while (j * 2 < size) + j *= 2; + } else + j >>= ffz(j) + 1; + + return j; +} + +/* + * return array index previous to j when does in-order traverse + * of a binary tree which is stored in a linear array + */ +static unsigned int inorder_prev(unsigned int j, unsigned int 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 int __to_inorder(unsigned int j, + unsigned int size, + unsigned int extra) +{ + unsigned int b = fls(j); + unsigned int shift = fls(size - 1) - b; + + j ^= 1U << (b - 1); + j <<= 1; + j |= 1; + j <<= shift; + + if (j > extra) + j -= (j - extra) >> 1; + + return j; +} + +/* + * Return the cacheline index in bset_tree->data, where j is index + * from a linear array which stores the auxiliar binary tree + */ +static unsigned int to_inorder(unsigned int j, struct bset_tree *t) +{ + return __to_inorder(j, t->size, t->extra); +} + +static unsigned int __inorder_to_tree(unsigned int j, + unsigned int size, + unsigned int extra) +{ + unsigned int shift; + + if (j > extra) + j += j - extra; + + shift = ffs(j); + + j >>= shift; + j |= roundup_pow_of_two(size) >> shift; + + return j; +} + +/* + * Return an index from a linear array which stores the auxiliar binary + * tree, j is the cacheline index of t->data. + */ +static unsigned int inorder_to_tree(unsigned int 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 int size = 2; + size < 65536000; + size++) { + unsigned int extra = + (size - rounddown_pow_of_two(size - 1)) << 1; + unsigned int i = 1, j = rounddown_pow_of_two(size - 1); + + if (!(size % 4096)) + pr_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 int cacheline, + unsigned int offset) +{ + return ((void *) t->data) + cacheline * BSET_CACHELINE + offset * 8; +} + +static unsigned int bkey_to_cacheline(struct bset_tree *t, struct bkey *k) +{ + return ((void *) k - (void *) t->data) / BSET_CACHELINE; +} + +static unsigned int bkey_to_cacheline_offset(struct bset_tree *t, + unsigned int 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 int 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 int 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 int 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; +} + +/* + * Calculate mantissa value for struct bkey_float. + * If most significant bit of f->exponent is not set, then + * - f->exponent >> 6 is 0 + * - p[0] points to bkey->low + * - p[-1] borrows bits from KEY_INODE() of bkey->high + * if most isgnificant bits of f->exponent is set, then + * - f->exponent >> 6 is 1 + * - p[0] points to bits from KEY_INODE() of bkey->high + * - p[-1] points to other bits from KEY_INODE() of + * bkey->high too. + * See make_bfloat() to check when most significant bit of f->exponent + * is set or not. + */ +static inline unsigned int 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 int 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 l and r have different KEY_INODE values (different backing + * device), f->exponent records how many least significant bits + * are different in KEY_INODE values and sets most significant + * bits to 1 (by +64). + * If l and r have same KEY_INODE value, f->exponent records + * how many different bits in least significant bits of bkey->low. + * See bfloat_mantiss() how the most significant bit of + * f->exponent is used to calculate bfloat mantissa value. + */ + 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 int 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); + +/* + * Build auxiliary binary tree 'struct bset_tree *t', this tree is used to + * accelerate bkey search in a btree node (pointed by bset_tree->data in + * memory). After search in the auxiliar tree by calling bset_search_tree(), + * a struct bset_search_iter is returned which indicates range [l, r] from + * bset_tree->data where the searching bkey might be inside. Then a followed + * linear comparison does the exact search, see __bch_bset_search() for how + * the auxiliary tree is used. + */ +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 int j, cacheline = 1; + + b->last_set_unwritten = 0; + + bset_alloc_tree(b, t); + + t->size = min_t(unsigned int, + 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 int 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 int shift = bkey_u64s(k); + unsigned int 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 int bch_btree_insert_key(struct btree_keys *b, struct bkey *k, + struct bkey *replace_key) +{ + unsigned int status = BTREE_INSERT_STATUS_NO_INSERT; + struct bset *i = bset_tree_last(b)->data; + struct bkey *m, *prev = NULL; + struct btree_iter iter; + struct bkey preceding_key_on_stack = ZERO_KEY; + struct bkey *preceding_key_p = &preceding_key_on_stack; + + BUG_ON(b->ops->is_extents && !KEY_SIZE(k)); + + /* + * If k has preceding key, preceding_key_p will be set to address + * of k's preceding key; otherwise preceding_key_p will be set + * to NULL inside preceding_key(). + */ + if (b->ops->is_extents) + preceding_key(&START_KEY(k), &preceding_key_p); + else + preceding_key(k, &preceding_key_p); + + m = bch_btree_iter_init(b, &iter, preceding_key_p); + + 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 int li = 0, ri = t->size; + + while (li + 1 != ri) { + unsigned int 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 int inorder, j, n = 1; + + do { + /* + * A bit trick here. + * If p < t->size, (int)(p - t->size) is a minus value and + * the most significant bit is set, right shifting 31 bits + * gets 1. If p >= t->size, the most significant bit is + * not set, right shifting 31 bits gets 0. + * So the following 2 lines equals to + * if (p >= t->size) + * p = 0; + * but a branch instruction is avoided. + */ + unsigned int p = n << 4; + + p &= ((int) (p - t->size)) >> 31; + + prefetch(&t->tree[p]); + + j = n; + f = &t->tree[j]; + + /* + * Similar bit trick, use subtract operation to avoid a branch + * instruction. + * + * 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 int) + (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 b __maybe_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, b, 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) +{ + mempool_exit(&state->pool); +} + +int bch_bset_sort_state_init(struct bset_sort_state *state, + unsigned int page_order) +{ + spin_lock_init(&state->time.lock); + + state->page_order = page_order; + state->crit_factor = int_sqrt(1 << page_order); + + return mempool_init_page_pool(&state->pool, 1, page_order); +} +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 int start, unsigned int 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 int 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 int 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 int 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 int 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; + } + } +} |