diff options
| -rw-r--r-- | util/qht.c | 49 |
1 files changed, 28 insertions, 21 deletions
diff --git a/util/qht.c b/util/qht.c index 4dd9be8822..ff4d2e6974 100644 --- a/util/qht.c +++ b/util/qht.c @@ -133,7 +133,8 @@ struct qht_map { /* trigger a resize when n_added_buckets > n_buckets / div */ #define QHT_NR_ADDED_BUCKETS_THRESHOLD_DIV 8 -static void qht_do_resize(struct qht *ht, struct qht_map *new); +static void qht_do_resize_reset(struct qht *ht, struct qht_map *new, + bool reset); static void qht_grow_maybe(struct qht *ht); #ifdef QHT_DEBUG @@ -408,6 +409,16 @@ void qht_reset(struct qht *ht) qht_map_unlock_buckets(map); } +static inline void qht_do_resize(struct qht *ht, struct qht_map *new) +{ + qht_do_resize_reset(ht, new, false); +} + +static inline void qht_do_resize_and_reset(struct qht *ht, struct qht_map *new) +{ + qht_do_resize_reset(ht, new, true); +} + bool qht_reset_size(struct qht *ht, size_t n_elems) { struct qht_map *new = NULL; @@ -421,13 +432,7 @@ bool qht_reset_size(struct qht *ht, size_t n_elems) if (n_buckets != map->n_buckets) { new = qht_map_create(n_buckets); } - - qht_map_lock_buckets(map); - qht_map_reset__all_locked(map); - if (new) { - qht_do_resize(ht, new); - } - qht_map_unlock_buckets(map); + qht_do_resize_and_reset(ht, new); qemu_mutex_unlock(&ht->lock); return !!new; @@ -559,9 +564,7 @@ static __attribute__((noinline)) void qht_grow_maybe(struct qht *ht) if (qht_map_needs_resize(map)) { struct qht_map *new = qht_map_create(map->n_buckets * 2); - qht_map_lock_buckets(map); qht_do_resize(ht, new); - qht_map_unlock_buckets(map); } qemu_mutex_unlock(&ht->lock); } @@ -737,24 +740,31 @@ static void qht_map_copy(struct qht *ht, void *p, uint32_t hash, void *userp) } /* - * Call with ht->lock and all bucket locks held. - * - * Creating the @new map here would add unnecessary delay while all the locks - * are held--holding up the bucket locks is particularly bad, since no writes - * can occur while these are held. Thus, we let callers create the new map, - * hopefully without the bucket locks held. + * Atomically perform a resize and/or reset. + * Call with ht->lock held. */ -static void qht_do_resize(struct qht *ht, struct qht_map *new) +static void qht_do_resize_reset(struct qht *ht, struct qht_map *new, bool reset) { struct qht_map *old; old = ht->map; - g_assert_cmpuint(new->n_buckets, !=, old->n_buckets); + qht_map_lock_buckets(old); + if (reset) { + qht_map_reset__all_locked(old); + } + + if (new == NULL) { + qht_map_unlock_buckets(old); + return; + } + + g_assert_cmpuint(new->n_buckets, !=, old->n_buckets); qht_map_iter__all_locked(ht, old, qht_map_copy, new); qht_map_debug__all_locked(new); atomic_rcu_set(&ht->map, new); + qht_map_unlock_buckets(old); call_rcu(old, qht_map_destroy, rcu); } @@ -766,12 +776,9 @@ bool qht_resize(struct qht *ht, size_t n_elems) qemu_mutex_lock(&ht->lock); if (n_buckets != ht->map->n_buckets) { struct qht_map *new; - struct qht_map *old = ht->map; new = qht_map_create(n_buckets); - qht_map_lock_buckets(old); qht_do_resize(ht, new); - qht_map_unlock_buckets(old); ret = true; } qemu_mutex_unlock(&ht->lock); |