From: Lai Jiangshan Date: Mon, 28 Nov 2011 13:41:10 +0000 (-0500) Subject: add rculfhash-mm-mmap.c memory management X-Git-Tag: v0.7.0~43^2~35 X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=b0b5525153fce8abae07b9573da1d5169e02eb2b;p=urcu.git add rculfhash-mm-mmap.c memory management [ Edit by Mathieu Desnoyers: - change "buckets" for "mmap" to better show the mapping between the union member and the mm plugin. - 80 col coding style fixups. ] Signed-off-by: Lai Jiangshan Signed-off-by: Mathieu Desnoyers --- diff --git a/Makefile.am b/Makefile.am index 853ecd5..91a9fd1 100644 --- a/Makefile.am +++ b/Makefile.am @@ -35,7 +35,8 @@ if COMPAT_FUTEX COMPAT+=compat_futex.c endif -RCULFHASH=rculfhash.c rculfhash-mm-order.c rculfhash-mm-chunk.c +RCULFHASH = rculfhash.c rculfhash-mm-order.c rculfhash-mm-chunk.c \ + rculfhash-mm-mmap.c lib_LTLIBRARIES = liburcu-common.la \ liburcu.la liburcu-qsbr.la \ diff --git a/rculfhash-internal.h b/rculfhash-internal.h index f7c6590..cc14664 100644 --- a/rculfhash-internal.h +++ b/rculfhash-internal.h @@ -108,6 +108,12 @@ struct cds_lfht { * memory addressing. */ struct cds_lfht_node *tbl_chunk[0]; + + /* + * Memory mapping with room for all possible buckets. + * Their memory is allocated when needed. + */ + struct cds_lfht_node *tbl_mmap; }; }; diff --git a/rculfhash-mm-mmap.c b/rculfhash-mm-mmap.c new file mode 100644 index 0000000..542c884 --- /dev/null +++ b/rculfhash-mm-mmap.c @@ -0,0 +1,160 @@ +/* + * rculfhash-mm-mmap.c + * + * mmap/reservation based memory management for Lock-Free RCU Hash Table + * + * Copyright 2011 - Lai Jiangshan + * + * 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 +#include +#include "rculfhash-internal.h" + +/* 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 = munmap(ptr, length); + + assert(ret == 0); +} + +static void memory_populate(void *ptr, size_t length) +{ + void *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 = 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) +{ + struct cds_lfht *ht; + unsigned long page_bucket_size = getpagesize() / sizeof(*ht->tbl_mmap); + + 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); + } + + ht = calloc(1, sizeof(struct cds_lfht)); + assert(ht); + + ht->mm = &cds_lfht_mm_mmap; + + ht->min_nr_alloc_buckets = min_nr_alloc_buckets; + ht->min_alloc_buckets_order = + get_count_order_ulong(min_nr_alloc_buckets); + ht->max_nr_buckets = max_nr_buckets; + + ht->bucket_at = bucket_at; + + return ht; +} + +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, +}; diff --git a/urcu/rculfhash.h b/urcu/rculfhash.h index 1224ea8..6ed7c8c 100644 --- a/urcu/rculfhash.h +++ b/urcu/rculfhash.h @@ -106,6 +106,7 @@ struct cds_lfht_mm_type { extern const struct cds_lfht_mm_type cds_lfht_mm_order; extern const struct cds_lfht_mm_type cds_lfht_mm_chunk; +extern const struct cds_lfht_mm_type cds_lfht_mm_mmap; /* * _cds_lfht_new - API used by cds_lfht_new wrapper. Do not use directly.