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      1 // SPDX-FileCopyrightText: 2011 Lai Jiangshan <laijs (at) cn.fujitsu.com>
      2 //
      3 // SPDX-License-Identifier: LGPL-2.1-or-later
      4 
      5 /*
      6  * Chunk based memory management for Lock-Free RCU Hash Table
      7  */
      8 
      9 #include <stddef.h>
     10 #include <urcu/assert.h>
     11 #include "rculfhash-internal.h"
     12 
     13 static
     14 void cds_lfht_alloc_bucket_table(struct cds_lfht *ht, unsigned long order)
     15 {
     16 	if (order == 0) {
     17 		ht->tbl_chunk[0] = ht->alloc->calloc(ht->alloc->state,
     18 			ht->min_nr_alloc_buckets, sizeof(struct cds_lfht_node));
     19 		urcu_posix_assert(ht->tbl_chunk[0]);
     20 	} else if (order > ht->min_alloc_buckets_order) {
     21 		unsigned long i, len = 1UL << (order - 1 - ht->min_alloc_buckets_order);
     22 
     23 		for (i = len; i < 2 * len; i++) {
     24 			ht->tbl_chunk[i] = ht->alloc->calloc(ht->alloc->state,
     25 				ht->min_nr_alloc_buckets, sizeof(struct cds_lfht_node));
     26 			urcu_posix_assert(ht->tbl_chunk[i]);
     27 		}
     28 	}
     29 	/* Nothing to do for 0 < order && order <= ht->min_alloc_buckets_order */
     30 }
     31 
     32 /*
     33  * cds_lfht_free_bucket_table() should be called with decreasing order.
     34  * When cds_lfht_free_bucket_table(0) is called, it means the whole
     35  * lfht is destroyed.
     36  */
     37 static
     38 void cds_lfht_free_bucket_table(struct cds_lfht *ht, unsigned long order)
     39 {
     40 	if (order == 0)
     41 		poison_free(ht->alloc, ht->tbl_chunk[0]);
     42 	else if (order > ht->min_alloc_buckets_order) {
     43 		unsigned long i, len = 1UL << (order - 1 - ht->min_alloc_buckets_order);
     44 
     45 		for (i = len; i < 2 * len; i++)
     46 			poison_free(ht->alloc, ht->tbl_chunk[i]);
     47 	}
     48 	/* Nothing to do for 0 < order && order <= ht->min_alloc_buckets_order */
     49 }
     50 
     51 static
     52 struct cds_lfht_node *bucket_at(struct cds_lfht *ht, unsigned long index)
     53 {
     54 	unsigned long chunk, offset;
     55 
     56 	chunk = index >> ht->min_alloc_buckets_order;
     57 	offset = index & (ht->min_nr_alloc_buckets - 1);
     58 	return &ht->tbl_chunk[chunk][offset];
     59 }
     60 
     61 static
     62 struct cds_lfht *alloc_cds_lfht(unsigned long min_nr_alloc_buckets,
     63 		unsigned long max_nr_buckets, const struct cds_lfht_alloc *alloc)
     64 {
     65 	unsigned long nr_chunks, cds_lfht_size;
     66 
     67 	min_nr_alloc_buckets = max(min_nr_alloc_buckets,
     68 				max_nr_buckets / MAX_CHUNK_TABLE);
     69 	nr_chunks = max_nr_buckets / min_nr_alloc_buckets;
     70 	cds_lfht_size = offsetof(struct cds_lfht, tbl_chunk) +
     71 			sizeof(struct cds_lfht_node *) * nr_chunks;
     72 	cds_lfht_size = max(cds_lfht_size, sizeof(struct cds_lfht));
     73 
     74 	return __default_alloc_cds_lfht(
     75 			&cds_lfht_mm_chunk, alloc, cds_lfht_size,
     76 			min_nr_alloc_buckets, max_nr_buckets);
     77 }
     78 
     79 const struct cds_lfht_mm_type cds_lfht_mm_chunk = {
     80 	.alloc_cds_lfht = alloc_cds_lfht,
     81 	.alloc_bucket_table = cds_lfht_alloc_bucket_table,
     82 	.free_bucket_table = cds_lfht_free_bucket_table,
     83 	.bucket_at = bucket_at,
     84 };
     85