Function ng_bridge_rehash

freebsd/netgraph/ng_bridge.c:936–986

* Resize the hash table. We try to maintain the number of buckets * such that the load factor is in the range 0.25 to 1.0. * * If we can't get the new memory then we silently fail. This is OK * because things will still work and we'll try again soon anyway. */

 * because things will still work and we'll try again soon anyway.
 */
static void
ng_bridge_rehash(priv_p priv)
{
	struct ng_bridge_bucket *newTab;
	int oldBucket, newBucket;
	int newNumBuckets;
	u_int newMask;

	/* Is table too full or too empty? */
	if (priv->numHosts > priv->numBuckets
	    && (priv->numBuckets << 1) <= MAX_BUCKETS)
		newNumBuckets = priv->numBuckets << 1;
	else if (priv->numHosts < (priv->numBuckets >> 2)
	    && (priv->numBuckets >> 2) >= MIN_BUCKETS)
		newNumBuckets = priv->numBuckets >> 2;
	else
		return;
	newMask = newNumBuckets - 1;

	/* Allocate and initialize new table */
	newTab = malloc(newNumBuckets * sizeof(*newTab),
	    M_NETGRAPH_BRIDGE, M_NOWAIT | M_ZERO);
	if (newTab == NULL)
		return;

	/* Move all entries from old table to new table */
	for (oldBucket = 0; oldBucket < priv->numBuckets; oldBucket++) {
		struct ng_bridge_bucket *const oldList = &priv->tab[oldBucket];

		while (!SLIST_EMPTY(oldList)) {
			struct ng_bridge_hent *const hent
			    = SLIST_FIRST(oldList);

			SLIST_REMOVE_HEAD(oldList, next);
			newBucket = HASH(hent->host.addr, newMask);
			SLIST_INSERT_HEAD(&newTab[newBucket], hent, next);
		}
	}

	/* Replace old table with new one */
	if (priv->conf.debugLevel >= 3) {
		log(LOG_INFO, "ng_bridge: %s: table size %d -> %d\n",
		    ng_bridge_nodename(priv->node),
		    priv->numBuckets, newNumBuckets);
	}
	free(priv->tab, M_NETGRAPH_BRIDGE);
	priv->numBuckets = newNumBuckets;
	priv->hashMask = newMask;
	priv->tab = newTab;
	return;
}

/******************************************************************
		    MISC FUNCTIONS