+/*
+ * rculfhash-mm-order.c
+ *
+ * Order based memory management for Lock-Free RCU Hash Table
+ *
+ * Copyright 2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * Copyright 2011 - Lai Jiangshan <laijs@cn.fujitsu.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <rculfhash-internal.h>
+
+static
+void cds_lfht_alloc_bucket_table(struct cds_lfht *ht, unsigned long order)
+{
+ if (order == 0) {
+ ht->tbl_order[0] = calloc(ht->min_nr_alloc_buckets,
+ sizeof(struct cds_lfht_node));
+ assert(ht->tbl_order[0]);
+ } else if (order > ht->min_alloc_buckets_order) {
+ ht->tbl_order[order] = calloc(1UL << (order -1),
+ sizeof(struct cds_lfht_node));
+ assert(ht->tbl_order[order]);
+ }
+ /* Nothing to do for 0 < order && order <= ht->min_alloc_buckets_order */
+}
+
+/*
+ * cds_lfht_free_bucket_table() should be called with decreasing order.
+ * When cds_lfht_free_bucket_table(0) is called, it means the whole
+ * lfht is destroyed.
+ */
+static
+void cds_lfht_free_bucket_table(struct cds_lfht *ht, unsigned long order)
+{
+ if (order == 0)
+ poison_free(ht->tbl_order[0]);
+ else if (order > ht->min_alloc_buckets_order)
+ poison_free(ht->tbl_order[order]);
+ /* Nothing to do for 0 < order && order <= ht->min_alloc_buckets_order */
+}
+
+static
+struct cds_lfht_node *bucket_at(struct cds_lfht *ht, unsigned long index)
+{
+ unsigned long order;
+
+ if (index < ht->min_nr_alloc_buckets) {
+ dbg_printf("bucket index %lu order 0 aridx 0\n", index);
+ return &ht->tbl_order[0][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("bucket index %lu order %lu aridx %lu\n",
+ index, order, index & ((1UL << (order - 1)) - 1));
+ return &ht->tbl_order[order][index & ((1UL << (order - 1)) - 1)];
+}
+
+static
+struct cds_lfht *alloc_cds_lfht(unsigned long min_nr_alloc_buckets,
+ unsigned long max_nr_buckets)
+{
+ struct cds_lfht *ht;
+
+ ht = calloc(1, sizeof(struct cds_lfht));
+ assert(ht);
+
+ ht->mm = &cds_lfht_mm_order;
+
+ ht->min_nr_alloc_buckets = min_nr_alloc_buckets;
+ ht->min_alloc_buckets_order = get_count_order_ulong(min_nr_alloc_buckets);
+ ht->max_nr_buckets = max_nr_buckets;
+
+ ht->bucket_at = bucket_at;
+
+ return ht;
+}
+
+const struct cds_lfht_mm_type cds_lfht_mm_order = {
+ .alloc_cds_lfht = alloc_cds_lfht,
+ .alloc_bucket_table = cds_lfht_alloc_bucket_table,
+ .free_bucket_table = cds_lfht_free_bucket_table,
+ .bucket_at = bucket_at,
+};