![Kent Overstreet](/assets/img/avatar_default.png)
Never saw a profile of bset_search_tree() where it wasn't bottlenecked on memory until I got my new Haswell machine, but when I tried it there it was suddenly burning 20% of the cpu in the inner loop on shrd... Turns out, the version of shrd that takes 64 bit operands has a 9 cycle latency. hah. Signed-off-by: Kent Overstreet <kmo@daterainc.com>
1227 lines
27 KiB
C
1227 lines
27 KiB
C
/*
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* Code for working with individual keys, and sorted sets of keys with in a
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* btree node
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*
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* Copyright 2012 Google, Inc.
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*/
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#include "bcache.h"
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#include "btree.h"
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#include "debug.h"
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#include <linux/random.h>
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#include <linux/prefetch.h>
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/* Keylists */
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int bch_keylist_realloc(struct keylist *l, int nptrs, struct cache_set *c)
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{
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size_t oldsize = bch_keylist_nkeys(l);
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size_t newsize = oldsize + 2 + nptrs;
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uint64_t *old_keys = l->keys_p == l->inline_keys ? NULL : l->keys_p;
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uint64_t *new_keys;
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/* The journalling code doesn't handle the case where the keys to insert
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* is bigger than an empty write: If we just return -ENOMEM here,
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* bio_insert() and bio_invalidate() will insert the keys created so far
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* and finish the rest when the keylist is empty.
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*/
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if (newsize * sizeof(uint64_t) > block_bytes(c) - sizeof(struct jset))
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return -ENOMEM;
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newsize = roundup_pow_of_two(newsize);
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if (newsize <= KEYLIST_INLINE ||
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roundup_pow_of_two(oldsize) == newsize)
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return 0;
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new_keys = krealloc(old_keys, sizeof(uint64_t) * newsize, GFP_NOIO);
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if (!new_keys)
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return -ENOMEM;
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if (!old_keys)
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memcpy(new_keys, l->inline_keys, sizeof(uint64_t) * oldsize);
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l->keys_p = new_keys;
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l->top_p = new_keys + oldsize;
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return 0;
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}
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struct bkey *bch_keylist_pop(struct keylist *l)
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{
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struct bkey *k = l->keys;
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if (k == l->top)
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return NULL;
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while (bkey_next(k) != l->top)
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k = bkey_next(k);
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return l->top = k;
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}
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void bch_keylist_pop_front(struct keylist *l)
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{
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l->top_p -= bkey_u64s(l->keys);
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memmove(l->keys,
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bkey_next(l->keys),
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bch_keylist_bytes(l));
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}
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/* Pointer validation */
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static bool __ptr_invalid(struct cache_set *c, const struct bkey *k)
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{
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unsigned i;
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for (i = 0; i < KEY_PTRS(k); i++)
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if (ptr_available(c, k, i)) {
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struct cache *ca = PTR_CACHE(c, k, i);
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size_t bucket = PTR_BUCKET_NR(c, k, i);
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size_t r = bucket_remainder(c, PTR_OFFSET(k, i));
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if (KEY_SIZE(k) + r > c->sb.bucket_size ||
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bucket < ca->sb.first_bucket ||
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bucket >= ca->sb.nbuckets)
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return true;
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}
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return false;
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}
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bool bch_btree_ptr_invalid(struct cache_set *c, const struct bkey *k)
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{
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char buf[80];
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if (!KEY_PTRS(k) || !KEY_SIZE(k) || KEY_DIRTY(k))
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goto bad;
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if (__ptr_invalid(c, k))
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goto bad;
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return false;
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bad:
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bch_bkey_to_text(buf, sizeof(buf), k);
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cache_bug(c, "spotted btree ptr %s: %s", buf, bch_ptr_status(c, k));
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return true;
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}
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bool bch_extent_ptr_invalid(struct cache_set *c, const struct bkey *k)
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{
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char buf[80];
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if (!KEY_SIZE(k))
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return true;
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if (KEY_SIZE(k) > KEY_OFFSET(k))
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goto bad;
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if (__ptr_invalid(c, k))
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goto bad;
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return false;
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bad:
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bch_bkey_to_text(buf, sizeof(buf), k);
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cache_bug(c, "spotted extent %s: %s", buf, bch_ptr_status(c, k));
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return true;
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}
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static bool ptr_bad_expensive_checks(struct btree *b, const struct bkey *k,
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unsigned ptr)
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{
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struct bucket *g = PTR_BUCKET(b->c, k, ptr);
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char buf[80];
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if (mutex_trylock(&b->c->bucket_lock)) {
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if (b->level) {
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if (KEY_DIRTY(k) ||
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g->prio != BTREE_PRIO ||
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(b->c->gc_mark_valid &&
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GC_MARK(g) != GC_MARK_METADATA))
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goto err;
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} else {
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if (g->prio == BTREE_PRIO)
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goto err;
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if (KEY_DIRTY(k) &&
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b->c->gc_mark_valid &&
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GC_MARK(g) != GC_MARK_DIRTY)
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goto err;
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}
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mutex_unlock(&b->c->bucket_lock);
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}
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return false;
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err:
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mutex_unlock(&b->c->bucket_lock);
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bch_bkey_to_text(buf, sizeof(buf), k);
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btree_bug(b,
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"inconsistent pointer %s: bucket %zu pin %i prio %i gen %i last_gc %i mark %llu gc_gen %i",
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buf, PTR_BUCKET_NR(b->c, k, ptr), atomic_read(&g->pin),
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g->prio, g->gen, g->last_gc, GC_MARK(g), g->gc_gen);
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return true;
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}
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bool bch_ptr_bad(struct btree *b, const struct bkey *k)
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{
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struct bucket *g;
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unsigned i, stale;
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if (!bkey_cmp(k, &ZERO_KEY) ||
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!KEY_PTRS(k) ||
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bch_ptr_invalid(b, k))
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return true;
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for (i = 0; i < KEY_PTRS(k); i++) {
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if (!ptr_available(b->c, k, i))
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return true;
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g = PTR_BUCKET(b->c, k, i);
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stale = ptr_stale(b->c, k, i);
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btree_bug_on(stale > 96, b,
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"key too stale: %i, need_gc %u",
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stale, b->c->need_gc);
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btree_bug_on(stale && KEY_DIRTY(k) && KEY_SIZE(k),
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b, "stale dirty pointer");
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if (stale)
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return true;
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if (expensive_debug_checks(b->c) &&
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ptr_bad_expensive_checks(b, k, i))
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return true;
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}
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return false;
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}
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/* Key/pointer manipulation */
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void bch_bkey_copy_single_ptr(struct bkey *dest, const struct bkey *src,
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unsigned i)
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{
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BUG_ON(i > KEY_PTRS(src));
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/* Only copy the header, key, and one pointer. */
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memcpy(dest, src, 2 * sizeof(uint64_t));
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dest->ptr[0] = src->ptr[i];
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SET_KEY_PTRS(dest, 1);
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/* We didn't copy the checksum so clear that bit. */
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SET_KEY_CSUM(dest, 0);
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}
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bool __bch_cut_front(const struct bkey *where, struct bkey *k)
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{
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unsigned i, len = 0;
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if (bkey_cmp(where, &START_KEY(k)) <= 0)
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return false;
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if (bkey_cmp(where, k) < 0)
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len = KEY_OFFSET(k) - KEY_OFFSET(where);
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else
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bkey_copy_key(k, where);
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for (i = 0; i < KEY_PTRS(k); i++)
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SET_PTR_OFFSET(k, i, PTR_OFFSET(k, i) + KEY_SIZE(k) - len);
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BUG_ON(len > KEY_SIZE(k));
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SET_KEY_SIZE(k, len);
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return true;
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}
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bool __bch_cut_back(const struct bkey *where, struct bkey *k)
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{
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unsigned len = 0;
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if (bkey_cmp(where, k) >= 0)
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return false;
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BUG_ON(KEY_INODE(where) != KEY_INODE(k));
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if (bkey_cmp(where, &START_KEY(k)) > 0)
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len = KEY_OFFSET(where) - KEY_START(k);
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bkey_copy_key(k, where);
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BUG_ON(len > KEY_SIZE(k));
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SET_KEY_SIZE(k, len);
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return true;
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}
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static uint64_t merge_chksums(struct bkey *l, struct bkey *r)
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{
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return (l->ptr[KEY_PTRS(l)] + r->ptr[KEY_PTRS(r)]) &
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~((uint64_t)1 << 63);
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}
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/* Tries to merge l and r: l should be lower than r
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* Returns true if we were able to merge. If we did merge, l will be the merged
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* key, r will be untouched.
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*/
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bool bch_bkey_try_merge(struct btree *b, struct bkey *l, struct bkey *r)
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{
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unsigned i;
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if (key_merging_disabled(b->c))
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return false;
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if (KEY_PTRS(l) != KEY_PTRS(r) ||
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KEY_DIRTY(l) != KEY_DIRTY(r) ||
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bkey_cmp(l, &START_KEY(r)))
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return false;
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for (i = 0; i < KEY_PTRS(l); i++)
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if (l->ptr[i] + PTR(0, KEY_SIZE(l), 0) != r->ptr[i] ||
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PTR_BUCKET_NR(b->c, l, i) != PTR_BUCKET_NR(b->c, r, i))
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return false;
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/* Keys with no pointers aren't restricted to one bucket and could
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* overflow KEY_SIZE
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*/
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if (KEY_SIZE(l) + KEY_SIZE(r) > USHRT_MAX) {
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SET_KEY_OFFSET(l, KEY_OFFSET(l) + USHRT_MAX - KEY_SIZE(l));
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SET_KEY_SIZE(l, USHRT_MAX);
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bch_cut_front(l, r);
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return false;
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}
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if (KEY_CSUM(l)) {
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if (KEY_CSUM(r))
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l->ptr[KEY_PTRS(l)] = merge_chksums(l, r);
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else
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SET_KEY_CSUM(l, 0);
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}
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SET_KEY_OFFSET(l, KEY_OFFSET(l) + KEY_SIZE(r));
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SET_KEY_SIZE(l, KEY_SIZE(l) + KEY_SIZE(r));
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return true;
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}
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/* Binary tree stuff for auxiliary search trees */
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static unsigned inorder_next(unsigned j, unsigned size)
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{
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if (j * 2 + 1 < size) {
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j = j * 2 + 1;
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while (j * 2 < size)
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j *= 2;
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} else
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j >>= ffz(j) + 1;
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return j;
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}
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static unsigned inorder_prev(unsigned j, unsigned size)
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{
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if (j * 2 < size) {
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j = j * 2;
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while (j * 2 + 1 < size)
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j = j * 2 + 1;
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} else
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j >>= ffs(j);
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return j;
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}
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/* I have no idea why this code works... and I'm the one who wrote it
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*
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* However, I do know what it does:
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* Given a binary tree constructed in an array (i.e. how you normally implement
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* a heap), it converts a node in the tree - referenced by array index - to the
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* index it would have if you did an inorder traversal.
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*
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* Also tested for every j, size up to size somewhere around 6 million.
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*
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* The binary tree starts at array index 1, not 0
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* extra is a function of size:
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* extra = (size - rounddown_pow_of_two(size - 1)) << 1;
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*/
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static unsigned __to_inorder(unsigned j, unsigned size, unsigned extra)
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{
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unsigned b = fls(j);
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unsigned shift = fls(size - 1) - b;
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j ^= 1U << (b - 1);
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j <<= 1;
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j |= 1;
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j <<= shift;
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if (j > extra)
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j -= (j - extra) >> 1;
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return j;
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}
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static unsigned to_inorder(unsigned j, struct bset_tree *t)
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{
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return __to_inorder(j, t->size, t->extra);
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}
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static unsigned __inorder_to_tree(unsigned j, unsigned size, unsigned extra)
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{
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unsigned shift;
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if (j > extra)
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j += j - extra;
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shift = ffs(j);
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j >>= shift;
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j |= roundup_pow_of_two(size) >> shift;
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return j;
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}
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static unsigned inorder_to_tree(unsigned j, struct bset_tree *t)
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{
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return __inorder_to_tree(j, t->size, t->extra);
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}
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#if 0
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void inorder_test(void)
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{
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unsigned long done = 0;
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ktime_t start = ktime_get();
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for (unsigned size = 2;
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size < 65536000;
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size++) {
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unsigned extra = (size - rounddown_pow_of_two(size - 1)) << 1;
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unsigned i = 1, j = rounddown_pow_of_two(size - 1);
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if (!(size % 4096))
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printk(KERN_NOTICE "loop %u, %llu per us\n", size,
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done / ktime_us_delta(ktime_get(), start));
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while (1) {
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if (__inorder_to_tree(i, size, extra) != j)
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panic("size %10u j %10u i %10u", size, j, i);
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if (__to_inorder(j, size, extra) != i)
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panic("size %10u j %10u i %10u", size, j, i);
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if (j == rounddown_pow_of_two(size) - 1)
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break;
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BUG_ON(inorder_prev(inorder_next(j, size), size) != j);
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j = inorder_next(j, size);
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i++;
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}
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done += size - 1;
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}
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}
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#endif
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/*
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* Cacheline/offset <-> bkey pointer arithmetic:
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*
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* t->tree is a binary search tree in an array; each node corresponds to a key
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* in one cacheline in t->set (BSET_CACHELINE bytes).
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*
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* This means we don't have to store the full index of the key that a node in
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* the binary tree points to; to_inorder() gives us the cacheline, and then
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* bkey_float->m gives us the offset within that cacheline, in units of 8 bytes.
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*
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* cacheline_to_bkey() and friends abstract out all the pointer arithmetic to
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* make this work.
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*
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* To construct the bfloat for an arbitrary key we need to know what the key
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* immediately preceding it is: we have to check if the two keys differ in the
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* bits we're going to store in bkey_float->mantissa. t->prev[j] stores the size
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* of the previous key so we can walk backwards to it from t->tree[j]'s key.
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*/
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static struct bkey *cacheline_to_bkey(struct bset_tree *t, unsigned cacheline,
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unsigned offset)
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{
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return ((void *) t->data) + cacheline * BSET_CACHELINE + offset * 8;
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}
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|
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static unsigned bkey_to_cacheline(struct bset_tree *t, struct bkey *k)
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{
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return ((void *) k - (void *) t->data) / BSET_CACHELINE;
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}
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|
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static unsigned bkey_to_cacheline_offset(struct bkey *k)
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{
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return ((size_t) k & (BSET_CACHELINE - 1)) / sizeof(uint64_t);
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}
|
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|
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static struct bkey *tree_to_bkey(struct bset_tree *t, unsigned j)
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{
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return cacheline_to_bkey(t, to_inorder(j, t), t->tree[j].m);
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}
|
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|
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static struct bkey *tree_to_prev_bkey(struct bset_tree *t, unsigned j)
|
|
{
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return (void *) (((uint64_t *) tree_to_bkey(t, j)) - t->prev[j]);
|
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}
|
|
|
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/*
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* For the write set - the one we're currently inserting keys into - we don't
|
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* maintain a full search tree, we just keep a simple lookup table in t->prev.
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|
*/
|
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static struct bkey *table_to_bkey(struct bset_tree *t, unsigned cacheline)
|
|
{
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return cacheline_to_bkey(t, cacheline, t->prev[cacheline]);
|
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}
|
|
|
|
static inline uint64_t shrd128(uint64_t high, uint64_t low, uint8_t shift)
|
|
{
|
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low >>= shift;
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low |= (high << 1) << (63U - shift);
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return low;
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}
|
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|
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static inline unsigned bfloat_mantissa(const struct bkey *k,
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struct bkey_float *f)
|
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{
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const uint64_t *p = &k->low - (f->exponent >> 6);
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return shrd128(p[-1], p[0], f->exponent & 63) & BKEY_MANTISSA_MASK;
|
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}
|
|
|
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static void make_bfloat(struct bset_tree *t, unsigned j)
|
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{
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struct bkey_float *f = &t->tree[j];
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struct bkey *m = tree_to_bkey(t, j);
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struct bkey *p = tree_to_prev_bkey(t, j);
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|
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struct bkey *l = is_power_of_2(j)
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? t->data->start
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: tree_to_prev_bkey(t, j >> ffs(j));
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|
|
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struct bkey *r = is_power_of_2(j + 1)
|
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? node(t->data, t->data->keys - bkey_u64s(&t->end))
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: tree_to_bkey(t, j >> (ffz(j) + 1));
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|
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BUG_ON(m < l || m > r);
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BUG_ON(bkey_next(p) != m);
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|
|
|
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 *b, struct bset_tree *t)
|
|
{
|
|
if (t != b->sets) {
|
|
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->sets + MAX_BSETS)
|
|
t++->size = 0;
|
|
}
|
|
|
|
static void bset_build_unwritten_tree(struct btree *b)
|
|
{
|
|
struct bset_tree *t = b->sets + b->nsets;
|
|
|
|
bset_alloc_tree(b, t);
|
|
|
|
if (t->tree != b->sets->tree + bset_tree_space(b)) {
|
|
t->prev[0] = bkey_to_cacheline_offset(t->data->start);
|
|
t->size = 1;
|
|
}
|
|
}
|
|
|
|
static void bset_build_written_tree(struct btree *b)
|
|
{
|
|
struct bset_tree *t = b->sets + b->nsets;
|
|
struct bkey *k = t->data->start;
|
|
unsigned j, cacheline = 1;
|
|
|
|
bset_alloc_tree(b, t);
|
|
|
|
t->size = min_t(unsigned,
|
|
bkey_to_cacheline(t, end(t->data)),
|
|
b->sets->tree + bset_tree_space(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)
|
|
k = bkey_next(k);
|
|
|
|
t->prev[j] = bkey_u64s(k);
|
|
k = bkey_next(k);
|
|
cacheline++;
|
|
t->tree[j].m = bkey_to_cacheline_offset(k);
|
|
}
|
|
|
|
while (bkey_next(k) != end(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);
|
|
}
|
|
|
|
void bch_bset_fix_invalidated_key(struct btree *b, struct bkey *k)
|
|
{
|
|
struct bset_tree *t;
|
|
unsigned inorder, j = 1;
|
|
|
|
for (t = b->sets; t <= &b->sets[b->nsets]; t++)
|
|
if (k < end(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) == end(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);
|
|
}
|
|
|
|
void bch_bset_fix_lookup_table(struct btree *b, struct bkey *k)
|
|
{
|
|
struct bset_tree *t = &b->sets[b->nsets];
|
|
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
|
|
*/
|
|
if (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(k);
|
|
}
|
|
}
|
|
|
|
if (t->size == b->sets->tree + bset_tree_space(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 != end(t->data);
|
|
k = bkey_next(k))
|
|
if (t->size == bkey_to_cacheline(t, k)) {
|
|
t->prev[t->size] = bkey_to_cacheline_offset(k);
|
|
t->size++;
|
|
}
|
|
}
|
|
|
|
void bch_bset_init_next(struct btree *b)
|
|
{
|
|
struct bset *i = write_block(b);
|
|
|
|
if (i != b->sets[0].data) {
|
|
b->sets[++b->nsets].data = i;
|
|
i->seq = b->sets[0].data->seq;
|
|
} else
|
|
get_random_bytes(&i->seq, sizeof(uint64_t));
|
|
|
|
i->magic = bset_magic(&b->c->sb);
|
|
i->version = 0;
|
|
i->keys = 0;
|
|
|
|
bset_build_unwritten_tree(b);
|
|
}
|
|
|
|
struct bset_search_iter {
|
|
struct bkey *l, *r;
|
|
};
|
|
|
|
static struct bset_search_iter bset_search_write_set(struct btree *b,
|
|
struct bset_tree *t,
|
|
const struct bkey *search)
|
|
{
|
|
unsigned li = 0, ri = t->size;
|
|
|
|
BUG_ON(!b->nsets &&
|
|
t->size < bkey_to_cacheline(t, end(t->data)));
|
|
|
|
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) : end(t->data)
|
|
};
|
|
}
|
|
|
|
static struct bset_search_iter bset_search_tree(struct btree *b,
|
|
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 = end(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 *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 = end(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 end(t->data);
|
|
|
|
if (unlikely(bkey_cmp(search, t->data->start) < 0))
|
|
return t->data->start;
|
|
|
|
i = bset_search_tree(b, t, search);
|
|
} else
|
|
i = bset_search_write_set(b, t, search);
|
|
|
|
if (expensive_debug_checks(b->c)) {
|
|
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 != end(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;
|
|
}
|
|
|
|
/* Btree iterator */
|
|
|
|
/*
|
|
* Returns true if l > r - unless l == r, in which case returns true if l is
|
|
* older than r.
|
|
*
|
|
* Necessary for btree_sort_fixup() - if there are multiple keys that compare
|
|
* equal in different sets, we have to process them newest to oldest.
|
|
*/
|
|
static inline bool btree_iter_cmp(struct btree_iter_set l,
|
|
struct btree_iter_set r)
|
|
{
|
|
int64_t c = bkey_cmp(&START_KEY(l.k), &START_KEY(r.k));
|
|
|
|
return c ? c > 0 : l.k < r.k;
|
|
}
|
|
|
|
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));
|
|
}
|
|
|
|
struct bkey *__bch_btree_iter_init(struct btree *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 <= &b->sets[b->nsets]; start++) {
|
|
ret = bch_bset_search(b, start, search);
|
|
bch_btree_iter_push(iter, ret, end(start->data));
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
struct bkey *bch_btree_iter_next(struct btree_iter *iter)
|
|
{
|
|
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, btree_iter_cmp);
|
|
else
|
|
heap_sift(iter, 0, btree_iter_cmp);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
struct bkey *bch_btree_iter_next_filter(struct btree_iter *iter,
|
|
struct btree *b, ptr_filter_fn fn)
|
|
{
|
|
struct bkey *ret;
|
|
|
|
do {
|
|
ret = bch_btree_iter_next(iter);
|
|
} while (ret && fn(b, ret));
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* Mergesort */
|
|
|
|
static void sort_key_next(struct btree_iter *iter,
|
|
struct btree_iter_set *i)
|
|
{
|
|
i->k = bkey_next(i->k);
|
|
|
|
if (i->k == i->end)
|
|
*i = iter->data[--iter->used];
|
|
}
|
|
|
|
static void btree_sort_fixup(struct btree_iter *iter)
|
|
{
|
|
while (iter->used > 1) {
|
|
struct btree_iter_set *top = iter->data, *i = top + 1;
|
|
|
|
if (iter->used > 2 &&
|
|
btree_iter_cmp(i[0], i[1]))
|
|
i++;
|
|
|
|
if (bkey_cmp(top->k, &START_KEY(i->k)) <= 0)
|
|
break;
|
|
|
|
if (!KEY_SIZE(i->k)) {
|
|
sort_key_next(iter, i);
|
|
heap_sift(iter, i - top, btree_iter_cmp);
|
|
continue;
|
|
}
|
|
|
|
if (top->k > i->k) {
|
|
if (bkey_cmp(top->k, i->k) >= 0)
|
|
sort_key_next(iter, i);
|
|
else
|
|
bch_cut_front(top->k, i->k);
|
|
|
|
heap_sift(iter, i - top, btree_iter_cmp);
|
|
} else {
|
|
/* can't happen because of comparison func */
|
|
BUG_ON(!bkey_cmp(&START_KEY(top->k), &START_KEY(i->k)));
|
|
bch_cut_back(&START_KEY(i->k), top->k);
|
|
}
|
|
}
|
|
}
|
|
|
|
static void btree_mergesort(struct btree *b, struct bset *out,
|
|
struct btree_iter *iter,
|
|
bool fixup, bool remove_stale)
|
|
{
|
|
struct bkey *k, *last = NULL;
|
|
bool (*bad)(struct btree *, const struct bkey *) = remove_stale
|
|
? bch_ptr_bad
|
|
: bch_ptr_invalid;
|
|
|
|
while (!btree_iter_end(iter)) {
|
|
if (fixup && !b->level)
|
|
btree_sort_fixup(iter);
|
|
|
|
k = bch_btree_iter_next(iter);
|
|
if (bad(b, k))
|
|
continue;
|
|
|
|
if (!last) {
|
|
last = out->start;
|
|
bkey_copy(last, k);
|
|
} else if (b->level ||
|
|
!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 *b, struct btree_iter *iter,
|
|
unsigned start, unsigned order, bool fixup)
|
|
{
|
|
uint64_t start_time;
|
|
bool remove_stale = !b->written;
|
|
struct bset *out = (void *) __get_free_pages(__GFP_NOWARN|GFP_NOIO,
|
|
order);
|
|
if (!out) {
|
|
mutex_lock(&b->c->sort_lock);
|
|
out = b->c->sort;
|
|
order = ilog2(bucket_pages(b->c));
|
|
}
|
|
|
|
start_time = local_clock();
|
|
|
|
btree_mergesort(b, out, iter, fixup, remove_stale);
|
|
b->nsets = start;
|
|
|
|
if (!fixup && !start && b->written)
|
|
bch_btree_verify(b, out);
|
|
|
|
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 = bset_magic(&b->c->sb);
|
|
out->seq = b->sets[0].data->seq;
|
|
out->version = b->sets[0].data->version;
|
|
swap(out, b->sets[0].data);
|
|
|
|
if (b->c->sort == b->sets[0].data)
|
|
b->c->sort = out;
|
|
} else {
|
|
b->sets[start].data->keys = out->keys;
|
|
memcpy(b->sets[start].data->start, out->start,
|
|
(void *) end(out) - (void *) out->start);
|
|
}
|
|
|
|
if (out == b->c->sort)
|
|
mutex_unlock(&b->c->sort_lock);
|
|
else
|
|
free_pages((unsigned long) out, order);
|
|
|
|
if (b->written)
|
|
bset_build_written_tree(b);
|
|
|
|
if (!start)
|
|
bch_time_stats_update(&b->c->sort_time, start_time);
|
|
}
|
|
|
|
void bch_btree_sort_partial(struct btree *b, unsigned start)
|
|
{
|
|
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->sets[start]);
|
|
|
|
BUG_ON(b->sets[b->nsets].data == write_block(b) &&
|
|
(b->sets[b->nsets].size || b->nsets));
|
|
|
|
|
|
if (start) {
|
|
unsigned i;
|
|
|
|
for (i = start; i <= b->nsets; i++)
|
|
keys += b->sets[i].data->keys;
|
|
|
|
order = roundup_pow_of_two(__set_bytes(b->sets->data,
|
|
keys)) / PAGE_SIZE;
|
|
if (order)
|
|
order = ilog2(order);
|
|
}
|
|
|
|
__btree_sort(b, &iter, start, order, false);
|
|
|
|
EBUG_ON(b->written && oldsize >= 0 && bch_count_data(b) != oldsize);
|
|
}
|
|
|
|
void bch_btree_sort_and_fix_extents(struct btree *b, struct btree_iter *iter)
|
|
{
|
|
BUG_ON(!b->written);
|
|
__btree_sort(b, iter, 0, b->page_order, true);
|
|
}
|
|
|
|
void bch_btree_sort_into(struct btree *b, struct btree *new)
|
|
{
|
|
uint64_t start_time = local_clock();
|
|
|
|
struct btree_iter iter;
|
|
bch_btree_iter_init(b, &iter, NULL);
|
|
|
|
btree_mergesort(b, new->sets->data, &iter, false, true);
|
|
|
|
bch_time_stats_update(&b->c->sort_time, start_time);
|
|
|
|
bkey_copy_key(&new->key, &b->key);
|
|
new->sets->size = 0;
|
|
}
|
|
|
|
#define SORT_CRIT (4096 / sizeof(uint64_t))
|
|
|
|
void bch_btree_sort_lazy(struct btree *b)
|
|
{
|
|
unsigned crit = SORT_CRIT;
|
|
int i;
|
|
|
|
/* Don't sort if nothing to do */
|
|
if (!b->nsets)
|
|
goto out;
|
|
|
|
/* If not a leaf node, always sort */
|
|
if (b->level) {
|
|
bch_btree_sort(b);
|
|
return;
|
|
}
|
|
|
|
for (i = b->nsets - 1; i >= 0; --i) {
|
|
crit *= b->c->sort_crit_factor;
|
|
|
|
if (b->sets[i].data->keys < crit) {
|
|
bch_btree_sort_partial(b, i);
|
|
return;
|
|
}
|
|
}
|
|
|
|
/* Sort if we'd overflow */
|
|
if (b->nsets + 1 == MAX_BSETS) {
|
|
bch_btree_sort(b);
|
|
return;
|
|
}
|
|
|
|
out:
|
|
bset_build_written_tree(b);
|
|
}
|
|
|
|
/* Sysfs stuff */
|
|
|
|
struct bset_stats {
|
|
struct btree_op op;
|
|
size_t nodes;
|
|
size_t sets_written, sets_unwritten;
|
|
size_t bytes_written, bytes_unwritten;
|
|
size_t floats, failed;
|
|
};
|
|
|
|
static int btree_bset_stats(struct btree_op *op, struct btree *b)
|
|
{
|
|
struct bset_stats *stats = container_of(op, struct bset_stats, op);
|
|
unsigned i;
|
|
|
|
stats->nodes++;
|
|
|
|
for (i = 0; i <= b->nsets; i++) {
|
|
struct bset_tree *t = &b->sets[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;
|
|
}
|
|
}
|
|
|
|
return MAP_CONTINUE;
|
|
}
|
|
|
|
int bch_bset_print_stats(struct cache_set *c, char *buf)
|
|
{
|
|
struct bset_stats t;
|
|
int ret;
|
|
|
|
memset(&t, 0, sizeof(struct bset_stats));
|
|
bch_btree_op_init(&t.op, -1);
|
|
|
|
ret = bch_btree_map_nodes(&t.op, c, &ZERO_KEY, btree_bset_stats);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
return snprintf(buf, PAGE_SIZE,
|
|
"btree nodes: %zu\n"
|
|
"written sets: %zu\n"
|
|
"unwritten sets: %zu\n"
|
|
"written key bytes: %zu\n"
|
|
"unwritten key bytes: %zu\n"
|
|
"floats: %zu\n"
|
|
"failed: %zu\n",
|
|
t.nodes,
|
|
t.sets_written, t.sets_unwritten,
|
|
t.bytes_written, t.bytes_unwritten,
|
|
t.floats, t.failed);
|
|
}
|