}
/* If we have enough left over to be useful, split that off. */
-static int to_used_record(struct tdb_context *tdb,
- unsigned int zone_bits,
- tdb_off_t off,
- tdb_len_t needed,
- tdb_len_t total_len,
- tdb_len_t *actual)
+static size_t record_leftover(size_t keylen, size_t datalen,
+ bool want_extra, size_t total_len)
{
- struct tdb_used_record used;
- tdb_len_t leftover;
+ ssize_t leftover;
- leftover = total_len - needed;
- if (leftover < sizeof(struct tdb_free_record))
- leftover = 0;
+ /* We might *want* extra, but not have it, so leftover is negative. */
+ leftover = total_len - adjust_size(keylen, datalen, want_extra);
+ if (leftover < (ssize_t)sizeof(struct tdb_free_record))
+ return 0;
- *actual = total_len - leftover;
+ /* If we want extra anwyay, don't split unless we have 2x size. */
+ if (want_extra && leftover <= datalen / 2)
+ return 0;
- if (leftover) {
- if (add_free_record(tdb, zone_bits,
- off + sizeof(used) + *actual,
- total_len - needed))
- return -1;
- }
- return 0;
+ return leftover;
}
/* Note: we unlock the current bucket if we coalesce or fail. */
break;
}
+ if (unlikely(bucket_off(zone_off,
+ size_to_bucket(zone_bits, r->data_len))
+ != nb_off)) {
+ tdb_unlock_free_bucket(tdb, nb_off);
+ break;
+ }
+
if (remove_from_list(tdb, nb_off, end, r) == -1) {
tdb_unlock_free_bucket(tdb, nb_off);
goto err;
if (remove_from_list(tdb, b_off, off, r) == -1)
goto err;
- /* We have to drop this to avoid deadlocks. */
+ r = tdb_access_write(tdb, off, sizeof(*r), true);
+ if (!r)
+ goto err;
+
+ /* We have to drop this to avoid deadlocks, so make sure record
+ * doesn't get coalesced by someone else! */
+ r->magic_and_meta = TDB_COALESCING_MAGIC | zone_bits;
+ r->data_len = end - off - sizeof(struct tdb_used_record);
+ if (tdb_access_commit(tdb, r) != 0)
+ goto err;
+
tdb_unlock_free_bucket(tdb, b_off);
if (add_free_record(tdb, zone_bits, off, end - off) == -1)
tdb_off_t zone_off,
unsigned zone_bits,
tdb_off_t bucket,
- size_t size,
- tdb_len_t *actual)
+ size_t keylen, size_t datalen,
+ bool want_extra,
+ unsigned hashlow)
{
tdb_off_t off, b_off,best_off;
struct tdb_free_record pad, best = { 0 }, *r;
double multiplier;
+ size_t size = keylen + datalen;
again:
b_off = bucket_off(zone_off, bucket);
best.data_len = -1ULL;
best_off = 0;
- /* FIXME: Start with larger multiplier if we're growing. */
- multiplier = 1.0;
+
+ /* Get slack if we're after extra. */
+ if (want_extra)
+ multiplier = 1.5;
+ else
+ multiplier = 1.0;
/* Walk the list to see if any are large enough, getting less fussy
* as we go. */
}
if (best.data_len < size * multiplier && best_off)
- goto use_best;
+ break;
multiplier *= 1.01;
/* If we found anything at all, use it. */
if (best_off) {
- use_best:
+ struct tdb_used_record rec;
+ size_t leftover;
+
/* We're happy with this size: take it. */
if (remove_from_list(tdb, b_off, best_off, &best) != 0)
goto unlock_err;
+
+ leftover = record_leftover(keylen, datalen, want_extra,
+ best.data_len);
+
+ /* We need to mark non-free before we drop lock, otherwise
+ * coalesce() could try to merge it! */
+ if (set_header(tdb, &rec, keylen, datalen,
+ best.data_len - leftover,
+ hashlow, zone_bits) != 0)
+ goto unlock_err;
+
+ if (tdb_write_convert(tdb, best_off, &rec, sizeof(rec)) != 0)
+ goto unlock_err;
+
tdb_unlock_free_bucket(tdb, b_off);
- if (to_used_record(tdb, zone_bits, best_off, size,
- best.data_len, actual)) {
- return -1;
+ if (leftover) {
+ if (add_free_record(tdb, zone_bits,
+ best_off + sizeof(rec)
+ + best.data_len - leftover,
+ leftover))
+ return TDB_OFF_ERR;
}
return best_off;
}
}
/* Offset returned is within current zone (which it may alter). */
-static tdb_off_t get_free(struct tdb_context *tdb, size_t size,
- tdb_len_t *actual)
+static tdb_off_t get_free(struct tdb_context *tdb,
+ size_t keylen, size_t datalen, bool want_extra,
+ unsigned hashlow)
{
tdb_off_t start_zone = tdb->zone_off, off;
bool wrapped = false;
+ size_t size = adjust_size(keylen, datalen, want_extra);
+
+ /* If they are growing, add 50% to get to higher bucket. */
+ if (want_extra)
+ size += datalen / 2;
/* FIXME: If we don't get a hit in the first bucket we want,
* try changing zones for next time. That should help wear
/* Shortcut for really huge allocations... */
if ((size >> tdb->zhdr.zone_bits) != 0)
- continue;
+ goto next;
/* Start at exact size bucket, and search up... */
b = size_to_bucket(tdb->zhdr.zone_bits, size);
/* Try getting one from list. */
off = lock_and_alloc(tdb, tdb->zone_off,
tdb->zhdr.zone_bits,
- b, size, actual);
+ b, keylen, datalen, want_extra,
+ hashlow);
if (off == TDB_OFF_ERR)
return TDB_OFF_ERR;
if (off != 0)
/* Didn't work. Try next bucket. */
}
+ next:
/* Didn't work, try next zone, if it exists. */
if (!next_zone(tdb)) {
wrapped = true;
uint64_t hash, bool growing)
{
tdb_off_t off;
- tdb_len_t size, actual;
- struct tdb_used_record rec;
/* We can't hold pointers during this: we could unmap! */
assert(!tdb->direct_access);
- size = adjust_size(keylen, datalen, growing);
-
-again:
- off = get_free(tdb, size, &actual);
- if (unlikely(off == TDB_OFF_ERR))
- return off;
+ for (;;) {
+ off = get_free(tdb, keylen, datalen, growing, hash);
+ if (likely(off != 0))
+ break;
- if (unlikely(off == 0)) {
- if (tdb_expand(tdb, size) == -1)
+ if (tdb_expand(tdb, adjust_size(keylen, datalen, growing)))
return TDB_OFF_ERR;
- goto again;
}
- /* Some supergiant values can't be encoded. */
- /* FIXME: Check before, and limit actual in get_free. */
- if (set_header(tdb, &rec, keylen, datalen, actual, hash,
- tdb->zhdr.zone_bits) != 0) {
- add_free_record(tdb, tdb->zhdr.zone_bits, off,
- sizeof(rec) + actual);
- return TDB_OFF_ERR;
- }
-
- if (tdb_write_convert(tdb, off, &rec, sizeof(rec)) != 0)
- return TDB_OFF_ERR;
-
return off;
}
projects / ccan / blobdiff