X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=rculfhash.c;h=5ef2c781e3f6330ca631910df85f0a8ef92de954;hb=c1888f3a47cf8f7c213269888ce42d191de7e34a;hp=6c648f17da8a939d22894067eb1cc8c24620a8e0;hpb=c0b8a8653e108be201ae8d1ca9918461c97d45ed;p=urcu.git

diff --git a/rculfhash.c b/rculfhash.c
index 6c648f1..5ef2c78 100644
--- a/rculfhash.c
+++ b/rculfhash.c
@@ -1271,6 +1271,36 @@ struct cds_lfht *_cds_lfht_new(unsigned long init_size,
 	if (!init_size || (init_size & (init_size - 1)))
 		return NULL;
 
+	/*
+	 * Memory management plugin default.
+	 */
+	if (!mm) {
+		if (!max_nr_buckets) {
+			/*
+			 * If the maximum number of buckets is not
+			 * specified, we cannot use the mmap allocator,
+			 * so fallback on order allocator.
+			 */
+			mm = &cds_lfht_mm_order;
+		} else if (CAA_BITS_PER_LONG > 32
+				&& max_nr_buckets <= (1ULL << 32)) {
+			/*
+			 * For 64-bit architectures, with max number of
+			 * buckets small enough not to use the entire
+			 * 64-bit memory mapping space (and allowing a
+			 * fair number of hash table instances), use the
+			 * mmap allocator, which is faster than the
+			 * order allocator.
+			 */
+			mm = &cds_lfht_mm_mmap;
+		} else {
+			/*
+			 * The fallback is to use the order allocator.
+			 */
+			mm = &cds_lfht_mm_order;
+		}
+	}
+
 	/* max_nr_buckets == 0 for order based mm means infinite */
 	if (mm == &cds_lfht_mm_order && !max_nr_buckets)
 		max_nr_buckets = 1UL << (MAX_TABLE_ORDER - 1);