int tdb_flist_init(struct tdb_context *tdb)
{
/* Use reservoir sampling algorithm to select a free list at random. */
- unsigned int rnd, max = 0;
+ unsigned int rnd, max = 0, count = 0;
tdb_off_t off;
tdb->flist_off = off = first_flist(tdb);
+ tdb->flist = 0;
while (off) {
if (off == TDB_OFF_ERR)
rnd = random();
if (rnd >= max) {
tdb->flist_off = off;
+ tdb->flist = count;
max = rnd;
}
off = next_flist(tdb, off);
+ count++;
}
return 0;
}
tdb_off_t off;
/* Front of list? */
- if (r->prev == 0) {
+ if (frec_prev(r) == 0) {
off = b_off;
} else {
- off = r->prev + offsetof(struct tdb_free_record, next);
+ off = frec_prev(r) + offsetof(struct tdb_free_record, next);
}
#ifdef DEBUG
}
if (r->next != 0) {
- off = r->next + offsetof(struct tdb_free_record, prev);
+ off = r->next + offsetof(struct tdb_free_record,magic_and_prev);
/* r->next->prev = r->prev */
#ifdef DEBUG
- if (tdb_read_off(tdb, off) != r_off) {
+ if (tdb_read_off(tdb, off) & TDB_OFF_MASK != r_off) {
tdb->log(tdb, TDB_DEBUG_FATAL, tdb->log_priv,
"remove_from_list: %llu bad list %llu\n",
(long long)r_off, (long long)b_off);
}
#endif
- if (tdb_write_off(tdb, off, r->prev)) {
+ if (tdb_write_off(tdb, off, r->magic_and_prev)) {
return -1;
}
}
static int enqueue_in_free(struct tdb_context *tdb,
tdb_off_t b_off,
tdb_off_t off,
- struct tdb_free_record *new)
+ tdb_len_t len)
{
- new->prev = 0;
+ struct tdb_free_record new;
+ uint64_t magic = (TDB_FREE_MAGIC << (64 - TDB_OFF_UPPER_STEAL));
+
+ /* We only need to set flist_and_len; rest is set in enqueue_in_free */
+ new.flist_and_len = ((uint64_t)tdb->flist << (64 - TDB_OFF_UPPER_STEAL))
+ | len;
+ /* prev = 0. */
+ new.magic_and_prev = magic;
+
/* new->next = head. */
- new->next = tdb_read_off(tdb, b_off);
- if (new->next == TDB_OFF_ERR)
+ new.next = tdb_read_off(tdb, b_off);
+ if (new.next == TDB_OFF_ERR)
return -1;
- if (new->next) {
+ if (new.next) {
#ifdef DEBUG
if (tdb_read_off(tdb,
- new->next
- + offsetof(struct tdb_free_record, prev))
- != 0) {
+ new.next + offsetof(struct tdb_free_record,
+ magic_and_prev))
+ != magic) {
tdb->log(tdb, TDB_DEBUG_FATAL, tdb->log_priv,
"enqueue_in_free: %llu bad head prev %llu\n",
- (long long)new->next, (long long)b_off);
+ (long long)new.next, (long long)b_off);
return -1;
}
#endif
/* next->prev = new. */
- if (tdb_write_off(tdb, new->next
- + offsetof(struct tdb_free_record, prev),
- off) != 0)
+ if (tdb_write_off(tdb, new.next
+ + offsetof(struct tdb_free_record,
+ magic_and_prev),
+ off | magic) != 0)
return -1;
}
/* head = new */
if (tdb_write_off(tdb, b_off, off) != 0)
return -1;
- return tdb_write_convert(tdb, off, new, sizeof(*new));
+ return tdb_write_convert(tdb, off, &new, sizeof(new));
}
/* List need not be locked. */
int add_free_record(struct tdb_context *tdb,
tdb_off_t off, tdb_len_t len_with_header)
{
- struct tdb_free_record new;
tdb_off_t b_off;
+ tdb_len_t len;
int ret;
- assert(len_with_header >= sizeof(new));
+ assert(len_with_header >= sizeof(struct tdb_free_record));
- new.magic_and_meta = TDB_FREE_MAGIC << (64 - TDB_OFF_UPPER_STEAL)
- | tdb->flist_off;
- new.data_len = len_with_header - sizeof(struct tdb_used_record);
+ len = len_with_header - sizeof(struct tdb_used_record);
- b_off = bucket_off(tdb->flist_off, size_to_bucket(new.data_len));
+ b_off = bucket_off(tdb->flist_off, size_to_bucket(len));
if (tdb_lock_free_bucket(tdb, b_off, TDB_LOCK_WAIT) != 0)
return -1;
- ret = enqueue_in_free(tdb, b_off, off, &new);
+ ret = enqueue_in_free(tdb, b_off, off, len);
tdb_unlock_free_bucket(tdb, b_off);
return ret;
}
return leftover;
}
+/* FIXME: Shortcut common case where tdb->flist == flist */
+static tdb_off_t flist_offset(struct tdb_context *tdb, unsigned int flist)
+{
+ tdb_off_t off = first_flist(tdb);
+ unsigned int i;
+
+ for (i = 0; i < flist; i++)
+ off = next_flist(tdb, off);
+ return off;
+}
+
/* Note: we unlock the current bucket if we coalesce or fail. */
static int coalesce(struct tdb_context *tdb,
tdb_off_t off, tdb_off_t b_off, tdb_len_t data_len)
while (end < tdb->map_size) {
tdb_off_t nb_off;
+ unsigned flist, bucket;
/* FIXME: do tdb_get here and below really win? */
r = tdb_get(tdb, end, &pad, sizeof(pad));
if (frec_magic(r) != TDB_FREE_MAGIC)
break;
- nb_off = bucket_off(frec_flist(r), size_to_bucket(r->data_len));
+ flist = frec_flist(r);
+ bucket = size_to_bucket(frec_len(r));
+ nb_off = bucket_off(flist_offset(tdb, flist), bucket);
/* We may be violating lock order here, so best effort. */
if (tdb_lock_free_bucket(tdb, nb_off, TDB_LOCK_NOWAIT) == -1)
break;
}
- if (unlikely(bucket_off(frec_flist(r),
- size_to_bucket(r->data_len))
- != nb_off)) {
+ if (unlikely(frec_flist(r) != flist)
+ || unlikely(size_to_bucket(frec_len(r)) != bucket)) {
tdb_unlock_free_bucket(tdb, nb_off);
break;
}
goto err;
}
- end += sizeof(struct tdb_used_record) + r->data_len;
+ end += sizeof(struct tdb_used_record) + frec_len(r);
tdb_unlock_free_bucket(tdb, nb_off);
}
if (!r)
goto err;
- if (r->data_len != data_len) {
+ if (frec_len(r) != data_len) {
tdb->ecode = TDB_ERR_CORRUPT;
tdb->log(tdb, TDB_DEBUG_FATAL, tdb->log_priv,
"coalesce: expected data len %llu not %llu\n",
- (long long)data_len, (long long)r->data_len);
+ (long long)data_len, (long long)frec_len(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 << (64 - TDB_OFF_UPPER_STEAL);
- r->data_len = end - off - sizeof(struct tdb_used_record);
+ r->magic_and_prev = TDB_COALESCING_MAGIC << (64 - TDB_OFF_UPPER_STEAL);
+ /* FIXME: Use 255 as invalid free list? */
+ r->flist_and_len = end - off - sizeof(struct tdb_used_record);
if (tdb_access_commit(tdb, r) != 0)
goto err;
return TDB_OFF_ERR;
}
- best.data_len = -1ULL;
+ best.flist_and_len = -1ULL;
best_off = 0;
/* Get slack if we're after extra. */
if (frec_magic(r) != TDB_FREE_MAGIC) {
tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
"lock_and_alloc: %llu non-free 0x%llx\n",
- (long long)off, (long long)r->magic_and_meta);
+ (long long)off, (long long)r->magic_and_prev);
goto unlock_err;
}
- if (r->data_len >= size && r->data_len < best.data_len) {
+ if (frec_len(r) >= size && frec_len(r) < frec_len(&best)) {
best_off = off;
best = *r;
}
- if (best.data_len < size * multiplier && best_off)
+ if (frec_len(&best) < size * multiplier && best_off)
break;
multiplier *= 1.01;
/* Since we're going slow anyway, try coalescing here. */
- switch (coalesce(tdb, off, b_off, r->data_len)) {
+ switch (coalesce(tdb, off, b_off, frec_len(r))) {
case -1:
/* This has already unlocked on error. */
return -1;
goto unlock_err;
leftover = record_leftover(keylen, datalen, want_extra,
- best.data_len);
+ frec_len(&best));
- assert(keylen + datalen + leftover <= best.data_len);
+ assert(keylen + datalen + leftover <= frec_len(&best));
/* We need to mark non-free before we drop lock, otherwise
* coalesce() could try to merge it! */
if (set_used_header(tdb, &rec, keylen, datalen,
- best.data_len - leftover,
+ frec_len(&best) - leftover,
hashlow) != 0)
goto unlock_err;
if (leftover) {
if (add_free_record(tdb,
best_off + sizeof(rec)
- + best.data_len - leftover,
+ + frec_len(&best) - leftover,
leftover))
return TDB_OFF_ERR;
}
size_t keylen, size_t datalen, bool want_extra,
unsigned hashlow)
{
- tdb_off_t off, flist;
- unsigned start_b, b;
+ tdb_off_t off, flist_off;
+ unsigned start_b, b, flist;
bool wrapped = false;
/* If they are growing, add 50% to get to higher bucket. */
else
start_b = size_to_bucket(adjust_size(keylen, datalen));
- flist = tdb->flist_off;
- while (!wrapped || flist != tdb->flist_off) {
+ flist_off = tdb->flist_off;
+ flist = tdb->flist;
+ while (!wrapped || flist_off != tdb->flist_off) {
/* Start at exact size bucket, and search up... */
- for (b = find_free_head(tdb, flist, start_b);
+ for (b = find_free_head(tdb, flist_off, start_b);
b < TDB_FREE_BUCKETS;
- b = find_free_head(tdb, flist, b + 1)) {
+ b = find_free_head(tdb, flist_off, b + 1)) {
/* Try getting one from list. */
- off = lock_and_alloc(tdb, flist,
+ off = lock_and_alloc(tdb, flist_off,
b, keylen, datalen, want_extra,
hashlow);
if (off == TDB_OFF_ERR)
return TDB_OFF_ERR;
if (off != 0) {
/* Worked? Stay using this list. */
- tdb->flist_off = flist;
+ tdb->flist_off = flist_off;
+ tdb->flist = flist;
return off;
}
/* Didn't work. Try next bucket. */
}
/* Hmm, try next list. */
- flist = next_flist(tdb, flist);
- if (flist == 0) {
+ flist_off = next_flist(tdb, flist_off);
+ flist++;
+ if (flist_off == 0) {
wrapped = true;
- flist = first_flist(tdb);
+ flist_off = first_flist(tdb);
+ flist = 0;
}
}
projects / ccan / blobdiff