| 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 | |
| 24 | #include <rculfhash-internal.h> |
| 25 | |
| 26 | static |
| 27 | void cds_lfht_alloc_bucket_table(struct cds_lfht *ht, unsigned long order) |
| 28 | { |
| 29 | if (order == 0) { |
| 30 | ht->tbl_order[0] = calloc(ht->min_nr_alloc_buckets, |
| 31 | sizeof(struct cds_lfht_node)); |
| 32 | assert(ht->tbl_order[0]); |
| 33 | } else if (order > ht->min_alloc_buckets_order) { |
| 34 | ht->tbl_order[order] = calloc(1UL << (order -1), |
| 35 | sizeof(struct cds_lfht_node)); |
| 36 | assert(ht->tbl_order[order]); |
| 37 | } |
| 38 | /* Nothing to do for 0 < order && order <= ht->min_alloc_buckets_order */ |
| 39 | } |
| 40 | |
| 41 | /* |
| 42 | * cds_lfht_free_bucket_table() should be called with decreasing order. |
| 43 | * When cds_lfht_free_bucket_table(0) is called, it means the whole |
| 44 | * lfht is destroyed. |
| 45 | */ |
| 46 | static |
| 47 | void cds_lfht_free_bucket_table(struct cds_lfht *ht, unsigned long order) |
| 48 | { |
| 49 | if (order == 0) |
| 50 | poison_free(ht->tbl_order[0]); |
| 51 | else if (order > ht->min_alloc_buckets_order) |
| 52 | poison_free(ht->tbl_order[order]); |
| 53 | /* Nothing to do for 0 < order && order <= ht->min_alloc_buckets_order */ |
| 54 | } |
| 55 | |
| 56 | static |
| 57 | struct cds_lfht_node *bucket_at(struct cds_lfht *ht, unsigned long index) |
| 58 | { |
| 59 | unsigned long order; |
| 60 | |
| 61 | if (index < ht->min_nr_alloc_buckets) { |
| 62 | dbg_printf("bucket index %lu order 0 aridx 0\n", index); |
| 63 | return &ht->tbl_order[0][index]; |
| 64 | } |
| 65 | /* |
| 66 | * equivalent to cds_lfht_get_count_order_ulong(index + 1), but |
| 67 | * optimizes away the non-existing 0 special-case for |
| 68 | * cds_lfht_get_count_order_ulong. |
| 69 | */ |
| 70 | order = cds_lfht_fls_ulong(index); |
| 71 | dbg_printf("bucket index %lu order %lu aridx %lu\n", |
| 72 | index, order, index & ((1UL << (order - 1)) - 1)); |
| 73 | return &ht->tbl_order[order][index & ((1UL << (order - 1)) - 1)]; |
| 74 | } |
| 75 | |
| 76 | static |
| 77 | struct cds_lfht *alloc_cds_lfht(unsigned long min_nr_alloc_buckets, |
| 78 | unsigned long max_nr_buckets) |
| 79 | { |
| 80 | return __default_alloc_cds_lfht( |
| 81 | &cds_lfht_mm_order, sizeof(struct cds_lfht), |
| 82 | min_nr_alloc_buckets, max_nr_buckets); |
| 83 | } |
| 84 | |
| 85 | const struct cds_lfht_mm_type cds_lfht_mm_order = { |
| 86 | .alloc_cds_lfht = alloc_cds_lfht, |
| 87 | .alloc_bucket_table = cds_lfht_alloc_bucket_table, |
| 88 | .free_bucket_table = cds_lfht_free_bucket_table, |
| 89 | .bucket_at = bucket_at, |
| 90 | }; |