#define TDB_MAGIC_FOOD "TDB file\n"
#define TDB_VERSION ((uint64_t)(0x26011967 + 7))
#define TDB_MAGIC ((uint64_t)0x1999)
-#define TDB_FREE_MAGIC (~(uint64_t)TDB_MAGIC)
+#define TDB_FREE_MAGIC ((~(uint64_t)TDB_MAGIC) << 6)
#define TDB_HASH_MAGIC (0xA1ABE11A01092008ULL)
#define TDB_RECOVERY_MAGIC (0xf53bc0e7U)
#define TDB_RECOVERY_INVALID_MAGIC (0x0)
-#define TDB_EXTRA_HASHBITS (11) /* We steal 11 bits to stash hash info. */
-#define TDB_EXTRA_HASHBITS_NUM (3)
#define TDB_OFF_ERR ((tdb_off_t)-1)
#define TDB_OPEN_LOCK 0
/* Doing a transaction. */
#define TDB_TRANSACTION_LOCK 1
+/* Expanding file. */
+#define TDB_EXPANSION_LOCK 2
/* Hash chain locks. */
-#define TDB_HASH_LOCK_START 2
+#define TDB_HASH_LOCK_START 3
-/* We start wih 256 hash buckets, 10 free buckets. A 4k-sized zone. */
+/* We start wih 256 hash buckets, and a 64k-sized zone. */
#define INITIAL_HASH_BITS 8
-#define INITIAL_FREE_BUCKETS 10
-#define INITIAL_ZONE_BITS 12
+#define INITIAL_ZONE_BITS 16
+
+/* Try to create zones at least 32 times larger than allocations. */
+#define TDB_COMFORT_FACTOR_BITS 5
+
+/* We ensure buckets up to size 1 << (zone_bits - TDB_COMFORT_FACTOR_BITS). */
+/* FIXME: test this matches size_to_bucket! */
+#define BUCKETS_FOR_ZONE(zone_bits) ((zone_bits) + 2 - TDB_COMFORT_FACTOR_BITS)
#if !HAVE_BSWAP_64
static inline uint64_t bswap_64(uint64_t x)
/* For on-disk compatibility, we avoid bitfields:
magic: 16, (highest)
key_len_bits: 5,
- hash:11,
- extra_padding: 32 (lowest)
+ extra_padding: 32
+ hash_bits: 5,
+ zone_bits: 6 (lowest)
*/
uint64_t magic_and_meta;
/* The bottom key_len_bits*2 are key length, rest is data length. */
static inline uint64_t rec_extra_padding(const struct tdb_used_record *r)
{
- return r->magic_and_meta & 0xFFFFFFFF;
+ return (r->magic_and_meta >> 11) & 0xFFFFFFFF;
+}
+
+static inline unsigned int rec_zone_bits(const struct tdb_used_record *r)
+{
+ return r->magic_and_meta & ((1 << 6) - 1);
}
-static inline uint64_t rec_hash(const struct tdb_used_record *r)
+static inline uint32_t rec_hash(const struct tdb_used_record *r)
{
- return ((r->magic_and_meta >> 32) & ((1ULL << 11) - 1));
+ return (r->magic_and_meta >> 6) & ((1 << 5) - 1);
}
static inline uint16_t rec_magic(const struct tdb_used_record *r)
}
struct tdb_free_record {
- uint64_t magic;
+ uint64_t magic_and_meta; /* Bottom 6 bits are zone bits. */
uint64_t data_len; /* Not counting these two fields. */
/* This is why the minimum record size is 16 bytes. */
uint64_t next, prev;
};
+static inline unsigned int frec_zone_bits(const struct tdb_free_record *f)
+{
+ return f->magic_and_meta & ((1 << 6) - 1);
+}
+
+static inline uint64_t frec_magic(const struct tdb_free_record *f)
+{
+ return f->magic_and_meta & ~((1ULL << 6) - 1);
+}
+
/* These parts can change while we have db open. */
struct tdb_header_volatile {
uint64_t generation; /* Makes sure it changes on every update. */
uint64_t hash_bits; /* Entries in hash table. */
uint64_t hash_off; /* Offset of hash table. */
- uint64_t num_zones; /* How many zones in the file. */
- uint64_t zone_bits; /* Size of zones. */
- uint64_t free_buckets; /* How many buckets in each zone. */
- uint64_t free_off; /* Arrays of free entries. */
};
/* this is stored at the front of every database */
struct tdb_header {
char magic_food[32]; /* for /etc/magic */
+ /* FIXME: Make me 32 bit? */
uint64_t version; /* version of the code */
uint64_t hash_test; /* result of hashing HASH_MAGIC. */
uint64_t hash_seed; /* "random" seed written at creation time. */
tdb_off_t reserved[19];
};
+/* Each zone has its set of free lists at the head.
+ *
+ * For each zone we have a series of per-size buckets, and a final bucket for
+ * "too big". */
+struct free_zone_header {
+ /* How much does this zone cover? */
+ uint64_t zone_bits;
+ /* tdb_off_t buckets[free_buckets + 1] */
+};
+
enum tdb_lock_flags {
/* WAIT == F_SETLKW, NOWAIT == F_SETLK */
TDB_LOCK_NOWAIT = 0,
struct tdb_transaction *transaction;
/* What zone of the tdb to use, for spreading load. */
- uint64_t last_zone;
+ uint64_t zone_off;
+ /* Cached copy of zone header. */
+ struct free_zone_header zhdr;
/* IO methods: changes for transactions. */
const struct tdb_methods *methods;
/* free.c: */
-void tdb_zone_init(struct tdb_context *tdb);
+int tdb_zone_init(struct tdb_context *tdb);
/* If this fails, try tdb_expand. */
tdb_off_t alloc(struct tdb_context *tdb, size_t keylen, size_t datalen,
uint64_t hash, bool growing);
/* Put this record in a free list. */
-int add_free_record(struct tdb_context *tdb,
+int add_free_record(struct tdb_context *tdb, unsigned int zone_bits,
tdb_off_t off, tdb_len_t len_with_header);
/* Set up header for a used record. */
int set_header(struct tdb_context *tdb,
struct tdb_used_record *rec,
uint64_t keylen, uint64_t datalen,
- uint64_t actuallen, uint64_t hash);
+ uint64_t actuallen, uint64_t hash,
+ unsigned int zone_bits);
/* Used by tdb_check to verify. */
-unsigned int size_to_bucket(struct tdb_context *tdb, tdb_len_t data_len);
-tdb_off_t zone_of(struct tdb_context *tdb, tdb_off_t off);
+unsigned int size_to_bucket(unsigned int free_buckets, tdb_len_t data_len);
+tdb_off_t bucket_off(tdb_off_t zone_off, tdb_off_t bucket);
/* io.c: */
/* Initialize tdb->methods. */
int ltype, enum tdb_lock_flags waitflag);
int tdb_unlock_list(struct tdb_context *tdb, tdb_off_t list, int ltype);
-/* Lock/unlock a particular free list. */
-int tdb_lock_free_list(struct tdb_context *tdb, tdb_off_t flist,
- enum tdb_lock_flags waitflag);
-void tdb_unlock_free_list(struct tdb_context *tdb, tdb_off_t flist);
+/* Lock/unlock a particular free bucket. */
+int tdb_lock_free_bucket(struct tdb_context *tdb, tdb_off_t b_off,
+ enum tdb_lock_flags waitflag);
+void tdb_unlock_free_bucket(struct tdb_context *tdb, tdb_off_t b_off);
/* Do we have any locks? */
bool tdb_has_locks(struct tdb_context *tdb);
/* Serialize db open. */
int tdb_lock_open(struct tdb_context *tdb);
void tdb_unlock_open(struct tdb_context *tdb);
+
+/* Serialize db expand. */
+int tdb_lock_expand(struct tdb_context *tdb, int ltype);
+void tdb_unlock_expand(struct tdb_context *tdb, int ltype);
+
/* Expand the file. */
int tdb_expand(struct tdb_context *tdb, tdb_len_t klen, tdb_len_t dlen,
bool growing);
projects / ccan / blobdiff