rculfhash: directly lookup bucket in the first order table

[ Edit by Mathieu Desnoyers: add a dbg_printf so the start-of-table
  lookup prints the same dbg messages as normal lookups. ]

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/rculfhash.c b/rculfhash.c
index 675ef382311beafcbb8d62ad284b2032d6db79aa..1f6ee71f39ddb05242d87a6b5c744144c7021c98 100644 (file)
--- a/rculfhash.c
+++ b/rculfhash.c
@@ -738,17 +738,21 @@ struct _cds_lfht_node *lookup_bucket(struct cds_lfht *ht, unsigned long size,
 
        assert(size > 0);
        index = hash & (size - 1);
+
+       if (index < ht->min_alloc_size) {
+               dbg_printf("lookup hash %lu index %lu order 0 aridx 0\n",
+                          hash, index);
+               return &ht->t.tbl[0]->nodes[index];
+       }
        /*
         * equivalent to get_count_order_ulong(index + 1), but optimizes
         * away the non-existing 0 special-case for
         * get_count_order_ulong.
         */
        order = fls_ulong(index);
-
        dbg_printf("lookup hash %lu index %lu order %lu aridx %lu\n",
-                  hash, index, order, index & (!order ? 0 : ((1UL << (order - 1)) - 1)));
-
-       return &ht->t.tbl[order]->nodes[index & (!order ? 0 : ((1UL << (order - 1)) - 1))];
+                  hash, index, order, index & ((1UL << (order - 1)) - 1));
+       return &ht->t.tbl[order]->nodes[index & ((1UL << (order - 1)) - 1)];
 }
 
 /*