+++ /dev/null
-/*
- * rculfhash-mm-mmap.c
- *
- * mmap/reservation based memory management for Lock-Free RCU Hash Table
- *
- * 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 <unistd.h>
-#include <sys/mman.h>
-#include "rculfhash-internal.h"
-
-#ifndef MAP_ANONYMOUS
-#define MAP_ANONYMOUS MAP_ANON
-#endif
-
-/* reserve inaccessible memory space without allocation any memory */
-static void *memory_map(size_t length)
-{
- void *ret = mmap(NULL, length, PROT_NONE,
- MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
-
- assert(ret != MAP_FAILED);
- return ret;
-}
-
-static void memory_unmap(void *ptr, size_t length)
-{
- int ret __attribute__((unused));
-
- ret = munmap(ptr, length);
-
- assert(ret == 0);
-}
-
-static void memory_populate(void *ptr, size_t length)
-{
- void *ret __attribute__((unused));
-
- ret = mmap(ptr, length, PROT_READ | PROT_WRITE,
- MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
-
- assert(ret == ptr);
-}
-
-/*
- * Discard garbage memory and avoid system save it when try to swap it out.
- * Make it still reserved, inaccessible.
- */
-static void memory_discard(void *ptr, size_t length)
-{
- void *ret __attribute__((unused));
-
- ret = mmap(ptr, length, PROT_NONE,
- MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
-
- assert(ret == ptr);
-}
-
-static
-void cds_lfht_alloc_bucket_table(struct cds_lfht *ht, unsigned long order)
-{
- if (order == 0) {
- if (ht->min_nr_alloc_buckets == ht->max_nr_buckets) {
- /* small table */
- ht->tbl_mmap = calloc(ht->max_nr_buckets,
- sizeof(*ht->tbl_mmap));
- assert(ht->tbl_mmap);
- return;
- }
- /* large table */
- ht->tbl_mmap = memory_map(ht->max_nr_buckets
- * sizeof(*ht->tbl_mmap));
- memory_populate(ht->tbl_mmap,
- ht->min_nr_alloc_buckets * sizeof(*ht->tbl_mmap));
- } else if (order > ht->min_alloc_buckets_order) {
- /* large table */
- unsigned long len = 1UL << (order - 1);
-
- assert(ht->min_nr_alloc_buckets < ht->max_nr_buckets);
- memory_populate(ht->tbl_mmap + len,
- len * sizeof(*ht->tbl_mmap));
- }
- /* 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) {
- if (ht->min_nr_alloc_buckets == ht->max_nr_buckets) {
- /* small table */
- poison_free(ht->tbl_mmap);
- return;
- }
- /* large table */
- memory_unmap(ht->tbl_mmap,
- ht->max_nr_buckets * sizeof(*ht->tbl_mmap));
- } else if (order > ht->min_alloc_buckets_order) {
- /* large table */
- unsigned long len = 1UL << (order - 1);
-
- assert(ht->min_nr_alloc_buckets < ht->max_nr_buckets);
- memory_discard(ht->tbl_mmap + len, len * sizeof(*ht->tbl_mmap));
- }
- /* 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)
-{
- return &ht->tbl_mmap[index];
-}
-
-static
-struct cds_lfht *alloc_cds_lfht(unsigned long min_nr_alloc_buckets,
- unsigned long max_nr_buckets)
-{
- unsigned long page_bucket_size;
-
- page_bucket_size = getpagesize() / sizeof(struct cds_lfht_node);
- if (max_nr_buckets <= page_bucket_size) {
- /* small table */
- min_nr_alloc_buckets = max_nr_buckets;
- } else {
- /* large table */
- min_nr_alloc_buckets = max(min_nr_alloc_buckets,
- page_bucket_size);
- }
-
- return __default_alloc_cds_lfht(
- &cds_lfht_mm_mmap, sizeof(struct cds_lfht),
- min_nr_alloc_buckets, max_nr_buckets);
-}
-
-const struct cds_lfht_mm_type cds_lfht_mm_mmap = {
- .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,
-};