Fix: relayd: don't call lttng_ht_destroy in RCU read-side C.S.
[lttng-tools.git] / src / common / hashtable / rculfhash-mm-order.c
CommitLineData
bec39940
DG
1/*
2 * rculfhash-mm-order.c
3 *
4 * Order based memory management for Lock-Free RCU Hash Table
5 *
6 * Copyright 2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
7 * Copyright 2011 - Lai Jiangshan <laijs@cn.fujitsu.com>
8 *
9 * This library is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Lesser General Public
11 * License as published by the Free Software Foundation; either
12 * version 2.1 of the License, or (at your option) any later version.
13 *
14 * This library is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * Lesser General Public License for more details.
18 *
19 * You should have received a copy of the GNU Lesser General Public
20 * License along with this library; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 */
23
6c1c0768
MD
24#define _GNU_SOURCE
25#define _LGPL_SOURCE
bec39940
DG
26#include "rculfhash-internal.h"
27
28static
29void cds_lfht_alloc_bucket_table(struct cds_lfht *ht, unsigned long order)
30{
31 if (order == 0) {
32 ht->tbl_order[0] = calloc(ht->min_nr_alloc_buckets,
33 sizeof(struct cds_lfht_node));
34 assert(ht->tbl_order[0]);
35 } else if (order > ht->min_alloc_buckets_order) {
36 ht->tbl_order[order] = calloc(1UL << (order -1),
37 sizeof(struct cds_lfht_node));
38 assert(ht->tbl_order[order]);
39 }
40 /* Nothing to do for 0 < order && order <= ht->min_alloc_buckets_order */
41}
42
43/*
44 * cds_lfht_free_bucket_table() should be called with decreasing order.
45 * When cds_lfht_free_bucket_table(0) is called, it means the whole
46 * lfht is destroyed.
47 */
48static
49void cds_lfht_free_bucket_table(struct cds_lfht *ht, unsigned long order)
50{
51 if (order == 0)
52 poison_free(ht->tbl_order[0]);
53 else if (order > ht->min_alloc_buckets_order)
54 poison_free(ht->tbl_order[order]);
55 /* Nothing to do for 0 < order && order <= ht->min_alloc_buckets_order */
56}
57
58static
59struct cds_lfht_node *bucket_at(struct cds_lfht *ht, unsigned long index)
60{
61 unsigned long order;
62
63 if (index < ht->min_nr_alloc_buckets) {
64 dbg_printf("bucket index %lu order 0 aridx 0\n", index);
65 return &ht->tbl_order[0][index];
66 }
67 /*
68 * equivalent to cds_lfht_get_count_order_ulong(index + 1), but
69 * optimizes away the non-existing 0 special-case for
70 * cds_lfht_get_count_order_ulong.
71 */
72 order = cds_lfht_fls_ulong(index);
73 dbg_printf("bucket index %lu order %lu aridx %lu\n",
74 index, order, index & ((1UL << (order - 1)) - 1));
75 return &ht->tbl_order[order][index & ((1UL << (order - 1)) - 1)];
76}
77
78static
79struct cds_lfht *alloc_cds_lfht(unsigned long min_nr_alloc_buckets,
80 unsigned long max_nr_buckets)
81{
82 return __default_alloc_cds_lfht(
83 &cds_lfht_mm_order, sizeof(struct cds_lfht),
84 min_nr_alloc_buckets, max_nr_buckets);
85}
86
87const struct cds_lfht_mm_type cds_lfht_mm_order = {
88 .alloc_cds_lfht = alloc_cds_lfht,
89 .alloc_bucket_table = cds_lfht_alloc_bucket_table,
90 .free_bucket_table = cds_lfht_free_bucket_table,
91 .bucket_at = bucket_at,
92};
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