src/common/hashtable/rculfhash-mm-chunk.c

   1 /*
   2  * rculfhash-mm-chunk.c
   3  *
   4  * Chunk based memory management for Lock-Free RCU Hash Table
   5  *
   6  * Copyright 2011 - Lai Jiangshan <laijs@cn.fujitsu.com>
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 #define _GNU_SOURCE
  24 #define _LGPL_SOURCE
  25 #include <stddef.h>
  26 #include "rculfhash-internal.h"
  27
  28 static
  29 void cds_lfht_alloc_bucket_table(struct cds_lfht *ht, unsigned long order)
  30 {
  31         if (order == 0) {
  32                 ht->tbl_chunk[0] = calloc(ht->min_nr_alloc_buckets,
  33                         sizeof(struct cds_lfht_node));
  34                 assert(ht->tbl_chunk[0]);
  35         } else if (order > ht->min_alloc_buckets_order) {
  36                 unsigned long i, len = 1UL << (order - 1 - ht->min_alloc_buckets_order);
  37
  38                 for (i = len; i < 2 * len; i++) {
  39                         ht->tbl_chunk[i] = calloc(ht->min_nr_alloc_buckets,
  40                                 sizeof(struct cds_lfht_node));
  41                         assert(ht->tbl_chunk[i]);
  42                 }
  43         }
  44         /* Nothing to do for 0 < order && order <= ht->min_alloc_buckets_order */
  45 }
  46
  47 /*
  48  * cds_lfht_free_bucket_table() should be called with decreasing order.
  49  * When cds_lfht_free_bucket_table(0) is called, it means the whole
  50  * lfht is destroyed.
  51  */
  52 static
  53 void cds_lfht_free_bucket_table(struct cds_lfht *ht, unsigned long order)
  54 {
  55         if (order == 0)
  56                 poison_free(ht->tbl_chunk[0]);
  57         else if (order > ht->min_alloc_buckets_order) {
  58                 unsigned long i, len = 1UL << (order - 1 - ht->min_alloc_buckets_order);
  59
  60                 for (i = len; i < 2 * len; i++)
  61                         poison_free(ht->tbl_chunk[i]);
  62         }
  63         /* Nothing to do for 0 < order && order <= ht->min_alloc_buckets_order */
  64 }
  65
  66 static
  67 struct cds_lfht_node *bucket_at(struct cds_lfht *ht, unsigned long index)
  68 {
  69         unsigned long chunk, offset;
  70
  71         chunk = index >> ht->min_alloc_buckets_order;
  72         offset = index & (ht->min_nr_alloc_buckets - 1);
  73         return &ht->tbl_chunk[chunk][offset];
  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         unsigned long nr_chunks, cds_lfht_size;
  81
  82         min_nr_alloc_buckets = max(min_nr_alloc_buckets,
  83                                 max_nr_buckets / MAX_CHUNK_TABLE);
  84         nr_chunks = max_nr_buckets / min_nr_alloc_buckets;
  85         cds_lfht_size = offsetof(struct cds_lfht, tbl_chunk) +
  86                         sizeof(struct cds_lfht_node *) * nr_chunks;
  87         cds_lfht_size = max(cds_lfht_size, sizeof(struct cds_lfht));
  88
  89         return __default_alloc_cds_lfht(
  90                         &cds_lfht_mm_chunk, cds_lfht_size,
  91                         min_nr_alloc_buckets, max_nr_buckets);
  92 }
  93
  94 const struct cds_lfht_mm_type cds_lfht_mm_chunk = {
  95         .alloc_cds_lfht = alloc_cds_lfht,
  96         .alloc_bucket_table = cds_lfht_alloc_bucket_table,
  97         .free_bucket_table = cds_lfht_free_bucket_table,
  98         .bucket_at = bucket_at,
  99 };