diff --git a/apc_cache.c b/apc_cache.c
index 9652a03d..b7c1bd03 100644
--- a/apc_cache.c
+++ b/apc_cache.c
@@ -753,11 +753,9 @@ PHP_APCU_API void apc_cache_default_expunge(apc_cache_t* cache, size_t size)
 	/* gc */
 	apc_cache_wlocked_gc(cache);
 
-	/* check that expunge is necessary */
-	if (cache->smart > 0L && apc_sma_get_avail_mem(cache->sma) >= (size_t) (cache->smart * size)) {
-		apc_cache_wunlock(cache);
-		return;
-	}
+	/* smart > 1 increases the probability of a full cache wipe,
+	 * so expunge() is called less often when memory is low. */
+	size = (cache->smart > 0L) ? (size_t) (cache->smart * size) : size;
 
 	/* look for junk */
 	for (i = 0; i < cache->nslots; i++) {
diff --git a/apc_cache.h b/apc_cache.h
index e987a546..2ee06169 100644
--- a/apc_cache.h
+++ b/apc_cache.h
@@ -251,20 +251,12 @@ PHP_APCU_API void apc_cache_serializer(apc_cache_t* cache, const char* name);
 
 /* {{{ apc_cache_default_expunge
 * Where smart is not set:
-*  Where no ttl is set on cache:
-*   1) Perform cleanup of stale entries
-*   2) Expunge if available memory is less than sma->size/2
-*  Where ttl is set on cache:
-*   1) Perform cleanup of stale entries
-*   2) If available memory if less than the size requested, run full expunge
+*  1) Perform cleanup of stale entries
+*  2) If available memory is less than the size requested, run full expunge
 *
 * Where smart is set:
-*  Where no ttl is set on cache:
-*   1) Perform cleanup of stale entries
-*   2) Expunge is available memory is less than size * smart
-*  Where ttl is set on cache:
-*   1) Perform cleanup of stale entries
-*   2) If available memory if less than the size requested, run full expunge
+*  1) Perform cleanup of stale entries
+*  2) If available memory is less than the size requested * smart, run full expunge
 *
 * The TTL of an entry takes precedence over the TTL of a cache
 */