rculfhash: create dummy nodes directly when create lfht

make cds_lfht_new() can be called earlier(before rcu is initialized
..etc) If caller want to *parallelly* init the dummy nodes with large
init_size, he can use cds_lfht_new()+cds_lfht_resize() combination.

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 b67acc820a078011f81963608f7c366fc1a3d2ec..8644f9c3f23ed184117eb2f74264cd9df121f19d 100644 (file)
--- a/rculfhash.c
+++ b/rculfhash.c
@@ -1266,6 +1266,45 @@ void fini_table(struct cds_lfht *ht,
        }
 }
 
+static
+void cds_lfht_create_dummy(struct cds_lfht *ht, unsigned long size)
+{
+       struct _cds_lfht_node *prev, *node;
+       unsigned long order, len, i, j;
+
+       ht->t.tbl[0] = calloc(1, sizeof(struct _cds_lfht_node));
+       assert(ht->t.tbl[0]);
+
+       dbg_printf("create dummy: order %lu index %lu hash %lu\n", 0, 0, 0);
+       ht->t.tbl[0]->nodes[0].next = flag_dummy(get_end());
+       ht->t.tbl[0]->nodes[0].reverse_hash = 0;
+
+       for (order = 1; order < get_count_order_ulong(size) + 1; order++) {
+               len = 1UL << (order - 1);
+               ht->t.tbl[order] = calloc(1, len * sizeof(struct _cds_lfht_node));
+               assert(ht->t.tbl[order]);
+
+               i = 0;
+               prev = ht->t.tbl[i]->nodes;
+               for (j = 0; j < len; j++) {
+                       if (j & (j - 1)) {      /* Between power of 2 */
+                               prev++;
+                       } else if (j) {         /* At each power of 2 */
+                               i++;
+                               prev = ht->t.tbl[i]->nodes;
+                       }
+
+                       node = &ht->t.tbl[order]->nodes[j];
+                       dbg_printf("create dummy: order %lu index %lu hash %lu\n",
+                                  order, j, j + len);
+                       node->next = prev->next;
+                       assert(is_dummy(node->next));
+                       node->reverse_hash = bit_reverse_ulong(j + len);
+                       prev->next = flag_dummy((struct cds_lfht_node *)node);
+               }
+       }
+}
+
 struct cds_lfht *_cds_lfht_new(cds_lfht_hash_fct hash_fct,
                        cds_lfht_compare_fct compare_fct,
                        unsigned long hash_seed,
@@ -1305,14 +1344,11 @@ struct cds_lfht *_cds_lfht_new(cds_lfht_hash_fct hash_fct,
        ht->percpu_count = alloc_per_cpu_items_count();
        /* this mutex should not nest in read-side C.S. */
        pthread_mutex_init(&ht->resize_mutex, NULL);
-       order = get_count_order_ulong(max(init_size, MIN_TABLE_SIZE));
        ht->flags = flags;
-       ht->cds_lfht_rcu_thread_offline();
-       pthread_mutex_lock(&ht->resize_mutex);
+       order = get_count_order_ulong(max(init_size, MIN_TABLE_SIZE));
        ht->t.resize_target = 1UL << order;
-       init_table(ht, 0, order);
-       pthread_mutex_unlock(&ht->resize_mutex);
-       ht->cds_lfht_rcu_thread_online();
+       cds_lfht_create_dummy(ht, 1UL << order);
+       ht->t.size = 1UL << order;
        return ht;
 }