tdb2: get rid of zones

[ccan] / ccan / tdb2 / private.h

diff --git a/ccan/tdb2/private.h b/ccan/tdb2/private.h
index 5e71bc2da46e1af4ec97c37489e1142cb62f9fe8..70580c46bfaa30916ff93dfea3aee71e3c6ae883 100644 (file)
--- a/ccan/tdb2/private.h
+++ b/ccan/tdb2/private.h
@@ -92,10 +92,8 @@ typedef uint64_t tdb_off_t;
 /* And 8 entries in each group, ie 8 groups per sublevel. */
 #define TDB_HASH_GROUP_BITS 3
 
-/* We start with a 64k-sized zone. */
-#define INITIAL_ZONE_BITS 16
-/* Try to create zones at least 32 times larger than allocations. */
-#define TDB_COMFORT_FACTOR_BITS 5
+/* Extend file by least 32 times larger than needed. */
+#define TDB_EXTENSION_FACTOR 32
 
 /* We steal bits from the offsets to store hash info. */
 #define TDB_OFF_HASH_GROUP_MASK ((1ULL << TDB_HASH_GROUP_BITS) - 1)
@@ -111,14 +109,13 @@ typedef uint64_t tdb_off_t;
 #define TDB_OFF_MASK \
        (((1ULL << (64 - TDB_OFF_UPPER_STEAL)) - 1) - TDB_OFF_HASH_GROUP_MASK)
 
+/* How many buckets in a free list: see size_to_bucket(). */
+#define TDB_FREE_BUCKETS (64 - TDB_OFF_UPPER_STEAL)
+
 /* We have to be able to fit a free record here. */
 #define TDB_MIN_DATA_LEN       \
        (sizeof(struct tdb_free_record) - sizeof(struct tdb_used_record))
 
-/* 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)
 {
@@ -138,8 +135,7 @@ struct tdb_used_record {
           magic: 16,        (highest)
           key_len_bits: 5,
           extra_padding: 32
-          hash_bits: 5,
-           zone_bits: 6 (lowest)
+          hash_bits: 11
        */
         uint64_t magic_and_meta;
        /* The bottom key_len_bits*2 are key length, rest is data length. */
@@ -166,14 +162,9 @@ static inline uint64_t rec_extra_padding(const struct tdb_used_record *r)
        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 uint32_t rec_hash(const struct tdb_used_record *r)
 {
-       return (r->magic_and_meta >> 6) & ((1 << 5) - 1);
+       return r->magic_and_meta & ((1 << 11) - 1);
 }
 
 static inline uint16_t rec_magic(const struct tdb_used_record *r)
@@ -182,32 +173,17 @@ static inline uint16_t rec_magic(const struct tdb_used_record *r)
 }
 
 struct tdb_free_record {
-        uint64_t magic_and_meta; /* Bottom 6 bits are zone bits. */
+        uint64_t magic_and_meta;
         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);
+       return f->magic_and_meta;
 }
 
-/* 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] */
-};
-
 /* this is stored at the front of every database */
 struct tdb_header {
        char magic_food[64]; /* for /etc/magic */
@@ -215,13 +191,19 @@ struct tdb_header {
        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 free_list; /* (First) free list. */
 
-       tdb_off_t reserved[28];
+       tdb_off_t reserved[27];
 
        /* Top level hash table. */
        tdb_off_t hashtable[1ULL << TDB_TOPLEVEL_HASH_BITS];
 };
 
+struct tdb_freelist {
+       struct tdb_used_record hdr;
+       tdb_off_t buckets[TDB_FREE_BUCKETS];
+};
+
 /* Information about a particular (locked) hash entry. */
 struct hash_info {
        /* Full hash value of entry. */
@@ -308,10 +290,8 @@ struct tdb_context {
        /* Set if we are in a transaction. */
        struct tdb_transaction *transaction;
        
-       /* What zone of the tdb to use, for spreading load. */
-       uint64_t zone_off;
-       /* Cached copy of zone header. */
-       struct free_zone_header zhdr;
+       /* What freelist are we using? */
+       uint64_t flist_off;
 
        /* IO methods: changes for transactions. */
        const struct tdb_methods *methods;
@@ -368,26 +348,25 @@ int delete_from_hash(struct tdb_context *tdb, struct hash_info *h);
 bool is_subhash(tdb_off_t val);
 
 /* free.c: */
-int tdb_zone_init(struct tdb_context *tdb);
+int tdb_flist_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, unsigned int zone_bits,
+int add_free_record(struct tdb_context *tdb,
                    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, unsigned hashlow,
-              unsigned int zone_bits);
+              uint64_t actuallen, unsigned hashlow);
 
 /* Used by tdb_check to verify. */
-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);
+unsigned int size_to_bucket(tdb_len_t data_len);
+tdb_off_t bucket_off(tdb_off_t flist_off, unsigned bucket);
 
 /* io.c: */
 /* Initialize tdb->methods. */