+// SPDX-FileCopyrightText: 2010-2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+// SPDX-FileCopyrightText: 2011 Lai Jiangshan <laijs@cn.fujitsu.com>
+//
+// SPDX-License-Identifier: LGPL-2.1-or-later
+
/*
- * rculfhash.c
- *
* Userspace RCU library - Lock-Free Resizable RCU Hash Table
- *
- * Copyright 2010-2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- * 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 <string.h>
#include <sched.h>
#include <unistd.h>
+#include <stdlib.h>
#include "compat-getcpu.h"
#include <urcu/assert.h>
#include <urcu/uatomic.h>
#include <urcu/compiler.h>
#include <urcu/rculfhash.h>
-#include <urcu/static/urcu-signal-nr.h>
#include <stdio.h>
#include <pthread.h>
#include <signal.h>
unsigned long start, unsigned long len);
};
+enum nr_cpus_mask_state {
+ NR_CPUS_MASK_INIT_FAILED = -2,
+ NR_CPUS_MASK_UNINITIALIZED = -1,
+};
+
static struct urcu_workqueue *cds_lfht_workqueue;
/*
#endif
}
+static void *cds_lfht_malloc(void *state __attribute__((unused)),
+ size_t size)
+{
+ return malloc(size);
+}
+
+static void *cds_lfht_calloc(void *state __attribute__((unused)),
+ size_t nmemb, size_t size)
+{
+ return calloc(nmemb, size);
+}
+
+static void *cds_lfht_realloc(void *state __attribute__((unused)),
+ void *ptr, size_t size)
+{
+ return realloc(ptr, size);
+}
+
+static void *cds_lfht_aligned_alloc(void *state __attribute__((unused)),
+ size_t alignment, size_t size)
+{
+ void *ptr;
+
+ if (posix_memalign(&ptr, alignment, size))
+ return NULL;
+ return ptr;
+}
+
+static void cds_lfht_free(void *state __attribute__((unused)), void *ptr)
+{
+ free(ptr);
+}
+
+
+/* Default memory allocator */
+static struct cds_lfht_alloc cds_lfht_default_alloc = {
+ .malloc = cds_lfht_malloc,
+ .calloc = cds_lfht_calloc,
+ .realloc = cds_lfht_realloc,
+ .aligned_alloc = cds_lfht_aligned_alloc,
+ .free = cds_lfht_free,
+ .state = NULL,
+};
+
/*
* Return the minimum order for which x <= (1UL << order).
* Return -1 if x is 0.
if (ret != EBUSY && ret != EINTR)
urcu_die(ret);
if (CMM_LOAD_SHARED(URCU_TLS(rcu_reader).need_mb)) {
- cmm_smp_mb();
- _CMM_STORE_SHARED(URCU_TLS(rcu_reader).need_mb, 0);
- cmm_smp_mb();
+ uatomic_store(&URCU_TLS(rcu_reader).need_mb, 0, CMM_SEQ_CST);
}
(void) poll(NULL, 0, 10);
}
urcu_die(ret);
}
-static long nr_cpus_mask = -1;
+static long nr_cpus_mask = NR_CPUS_MASK_UNINITIALIZED;
static long split_count_mask = -1;
static int split_count_order = -1;
maxcpus = get_possible_cpus_array_len();
if (maxcpus <= 0) {
- nr_cpus_mask = -2;
+ nr_cpus_mask = NR_CPUS_MASK_INIT_FAILED;
return;
}
/*
static
void alloc_split_items_count(struct cds_lfht *ht)
{
- if (nr_cpus_mask == -1) {
+ if (nr_cpus_mask == NR_CPUS_MASK_UNINITIALIZED) {
ht_init_nr_cpus_mask();
if (nr_cpus_mask < 0)
split_count_mask = DEFAULT_SPLIT_COUNT_MASK;
urcu_posix_assert(split_count_mask >= 0);
if (ht->flags & CDS_LFHT_ACCOUNTING) {
- ht->split_count = calloc(split_count_mask + 1,
+ ht->split_count = ht->alloc->calloc(ht->alloc->state, split_count_mask + 1,
sizeof(struct ht_items_count));
urcu_posix_assert(ht->split_count);
} else {
static
void free_split_items_count(struct cds_lfht *ht)
{
- poison_free(ht->split_count);
+ poison_free(ht->alloc, ht->split_count);
}
static
old1 = uatomic_read(ptr);
do {
old2 = old1;
- if (old2 >= v)
+ if (old2 >= v) {
+ cmm_smp_mb();
return old2;
+ }
} while ((old1 = uatomic_cmpxchg(ptr, old2, v)) != old2);
return old2;
}
struct cds_lfht_node *node)
{
struct cds_lfht_node *bucket, *next;
+ uintptr_t *node_next;
if (!node) /* Return -ENOENT if asked to delete NULL node */
return -ENOENT;
/*
* The del operation semantic guarantees a full memory barrier
* before the uatomic_or atomic commit of the deletion flag.
- */
- cmm_smp_mb__before_uatomic_or();
- /*
+ *
* We set the REMOVED_FLAG unconditionally. Note that there may
* be more than one concurrent thread setting this flag.
* Knowing which wins the race will be known after the garbage
* collection phase, stay tuned!
+ *
+ * NOTE: The node_next variable is present to avoid breaking
+ * strict-aliasing rules.
*/
- uatomic_or(&node->next, REMOVED_FLAG);
+ node_next = (uintptr_t*)&node->next;
+ uatomic_or_mo(node_next, REMOVED_FLAG, CMM_RELEASE);
+
/* We performed the (logical) deletion. */
/*
* was already set).
*/
if (!is_removal_owner(uatomic_xchg(&node->next,
- flag_removal_owner(node->next))))
+ flag_removal_owner(uatomic_load(&node->next, CMM_RELAXED)))))
return 0;
else
return -ENOENT;
unsigned long thread, nr_threads;
sigset_t newmask, oldmask;
- urcu_posix_assert(nr_cpus_mask != -1);
+ urcu_posix_assert(nr_cpus_mask != NR_CPUS_MASK_UNINITIALIZED);
if (nr_cpus_mask < 0 || len < 2 * MIN_PARTITION_PER_THREAD)
goto fallback;
nr_threads = 1;
}
partition_len = len >> cds_lfht_get_count_order_ulong(nr_threads);
- work = calloc(nr_threads, sizeof(*work));
+ work = ht->alloc->calloc(ht->alloc->state, nr_threads, sizeof(*work));
if (!work) {
dbg_printf("error allocating for resize, single-threading\n");
goto fallback;
ret = pthread_join(work[thread].thread_id, NULL);
urcu_posix_assert(!ret);
}
- free(work);
+ ht->alloc->free(ht->alloc->state, work);
/*
* A pthread_create failure above will either lead in us having
/*
* Update table size.
+ *
+ * Populate data before RCU size.
*/
- cmm_smp_wmb(); /* populate data before RCU size */
- CMM_STORE_SHARED(ht->size, 1UL << i);
+ uatomic_store(&ht->size, 1UL << i, CMM_RELEASE);
dbg_printf("init new size: %lu\n", 1UL << i);
if (CMM_LOAD_SHARED(ht->in_progress_destroy))
for (j = size + start; j < size + start + len; j++) {
struct cds_lfht_node *fini_bucket = bucket_at(ht, j);
struct cds_lfht_node *parent_bucket = bucket_at(ht, j - size);
+ uintptr_t *fini_bucket_next;
urcu_posix_assert(j >= size && j < (size << 1));
dbg_printf("remove entry: order %lu index %lu hash %lu\n",
i, j, j);
- /* Set the REMOVED_FLAG to freeze the ->next for gc */
- uatomic_or(&fini_bucket->next, REMOVED_FLAG);
+ /* Set the REMOVED_FLAG to freeze the ->next for gc.
+ *
+ * NOTE: The fini_bucket_next variable is present to
+ * avoid breaking strict-aliasing rules.
+ */
+ fini_bucket_next = (uintptr_t*)&fini_bucket->next;
+ uatomic_or(fini_bucket_next, REMOVED_FLAG);
_cds_lfht_gc_bucket(parent_bucket, fini_bucket);
}
ht->flavor->read_unlock();
node->next = flag_removed(NULL);
}
-struct cds_lfht *_cds_lfht_new(unsigned long init_size,
+struct cds_lfht *_cds_lfht_new_with_alloc(unsigned long init_size,
unsigned long min_nr_alloc_buckets,
unsigned long max_nr_buckets,
int flags,
const struct cds_lfht_mm_type *mm,
const struct rcu_flavor_struct *flavor,
+ const struct cds_lfht_alloc *alloc,
pthread_attr_t *attr)
{
struct cds_lfht *ht;
max_nr_buckets = max(max_nr_buckets, min_nr_alloc_buckets);
init_size = min(init_size, max_nr_buckets);
- ht = mm->alloc_cds_lfht(min_nr_alloc_buckets, max_nr_buckets);
+ ht = mm->alloc_cds_lfht(min_nr_alloc_buckets, max_nr_buckets, alloc ? : &cds_lfht_default_alloc);
+
urcu_posix_assert(ht);
urcu_posix_assert(ht->mm == mm);
urcu_posix_assert(ht->bucket_at == mm->bucket_at);
return ht;
}
+struct cds_lfht *_cds_lfht_new(unsigned long init_size,
+ unsigned long min_nr_alloc_buckets,
+ unsigned long max_nr_buckets,
+ int flags,
+ const struct cds_lfht_mm_type *mm,
+ const struct rcu_flavor_struct *flavor,
+ pthread_attr_t *attr)
+{
+ return _cds_lfht_new_with_alloc(init_size,
+ min_nr_alloc_buckets, max_nr_buckets,
+ flags, mm, flavor, NULL, attr);
+}
+
void cds_lfht_lookup(struct cds_lfht *ht, unsigned long hash,
cds_lfht_match_fct match, const void *key,
struct cds_lfht_iter *iter)
reverse_hash = bit_reverse_ulong(hash);
- size = rcu_dereference(ht->size);
+ /*
+ * Use load acquire instead of rcu_dereference because there is no
+ * dependency between the table size and the dereference of the bucket
+ * content.
+ *
+ * This acquire is paired with the store release in init_table().
+ */
+ size = uatomic_load(&ht->size, CMM_ACQUIRE);
bucket = lookup_bucket(ht, size, hash);
/* We can always skip the bucket node initially */
node = rcu_dereference(bucket->next);
}
node = clear_flag(next);
}
- urcu_posix_assert(!node || !is_bucket(CMM_LOAD_SHARED(node->next)));
+ urcu_posix_assert(!node || !is_bucket(uatomic_load(&node->next, CMM_RELAXED)));
iter->node = node;
iter->next = next;
}
}
node = clear_flag(next);
}
- urcu_posix_assert(!node || !is_bucket(CMM_LOAD_SHARED(node->next)));
+ urcu_posix_assert(!node || !is_bucket(uatomic_load(&node->next, CMM_RELAXED)));
iter->node = node;
iter->next = next;
}
* Get next after first bucket node. The first bucket node is the
* first node of the linked list.
*/
- iter->next = bucket_at(ht, 0)->next;
+ iter->next = uatomic_load(&bucket_at(ht, 0)->next, CMM_CONSUME);
cds_lfht_next(ht, iter);
}
unsigned long size;
node->reverse_hash = bit_reverse_ulong(hash);
- size = rcu_dereference(ht->size);
+ size = uatomic_load(&ht->size, CMM_ACQUIRE);
_cds_lfht_add(ht, hash, NULL, NULL, size, node, NULL, 0);
ht_count_add(ht, size, hash);
}
struct cds_lfht_iter iter;
node->reverse_hash = bit_reverse_ulong(hash);
- size = rcu_dereference(ht->size);
+ size = uatomic_load(&ht->size, CMM_ACQUIRE);
_cds_lfht_add(ht, hash, match, key, size, node, &iter, 0);
if (iter.node == node)
ht_count_add(ht, size, hash);
struct cds_lfht_iter iter;
node->reverse_hash = bit_reverse_ulong(hash);
- size = rcu_dereference(ht->size);
+ size = uatomic_load(&ht->size, CMM_ACQUIRE);
for (;;) {
_cds_lfht_add(ht, hash, match, key, size, node, &iter, 0);
if (iter.node == node) {
return -EINVAL;
if (caa_unlikely(!match(old_iter->node, key)))
return -EINVAL;
- size = rcu_dereference(ht->size);
+ size = uatomic_load(&ht->size, CMM_ACQUIRE);
return _cds_lfht_replace(ht, size, old_iter->node, old_iter->next,
new_node);
}
unsigned long size;
int ret;
- size = rcu_dereference(ht->size);
+ size = uatomic_load(&ht->size, CMM_ACQUIRE);
ret = _cds_lfht_del(ht, size, node);
if (!ret) {
unsigned long hash;
if (ret)
urcu_die(ret);
ht->flavor->unregister_thread();
- poison_free(ht);
+ poison_free(ht->alloc, ht);
}
/*
if (!cds_lfht_is_empty(ht))
return -EPERM;
/* Cancel ongoing resize operations. */
- _CMM_STORE_SHARED(ht->in_progress_destroy, 1);
+ uatomic_store(&ht->in_progress_destroy, 1, CMM_RELAXED);
if (attr) {
*attr = ht->caller_resize_attr;
ht->caller_resize_attr = NULL;
ret = pthread_mutex_destroy(&ht->resize_mutex);
if (ret)
ret = -EBUSY;
- poison_free(ht);
+ poison_free(ht->alloc, ht);
return ret;
}
* Resize table, re-do if the target size has changed under us.
*/
do {
- if (CMM_LOAD_SHARED(ht->in_progress_destroy))
+ if (uatomic_load(&ht->in_progress_destroy, CMM_RELAXED))
break;
- ht->resize_initiated = 1;
+
+ uatomic_store(&ht->resize_initiated, 1, CMM_RELAXED);
+
old_size = ht->size;
- new_size = CMM_LOAD_SHARED(ht->resize_target);
+ new_size = uatomic_load(&ht->resize_target, CMM_RELAXED);
if (old_size < new_size)
_do_cds_lfht_grow(ht, old_size, new_size);
else if (old_size > new_size)
_do_cds_lfht_shrink(ht, old_size, new_size);
- ht->resize_initiated = 0;
+
+ uatomic_store(&ht->resize_initiated, 0, CMM_RELAXED);
/* write resize_initiated before read resize_target */
cmm_smp_mb();
- } while (ht->size != CMM_LOAD_SHARED(ht->resize_target));
+ } while (ht->size != uatomic_load(&ht->resize_target, CMM_RELAXED));
}
static
void cds_lfht_resize(struct cds_lfht *ht, unsigned long new_size)
{
resize_target_update_count(ht, new_size);
- CMM_STORE_SHARED(ht->resize_initiated, 1);
+
+ /*
+ * Set flags has early as possible even in contention case.
+ */
+ uatomic_store(&ht->resize_initiated, 1, CMM_RELAXED);
+
mutex_lock(&ht->resize_mutex);
_do_cds_lfht_resize(ht);
mutex_unlock(&ht->resize_mutex);
_do_cds_lfht_resize(ht);
mutex_unlock(&ht->resize_mutex);
ht->flavor->unregister_thread();
- poison_free(work);
+ poison_free(ht->alloc, work);
}
static
{
struct resize_work *work;
- /* Store resize_target before read resize_initiated */
- cmm_smp_mb();
- if (!CMM_LOAD_SHARED(ht->resize_initiated)) {
- if (CMM_LOAD_SHARED(ht->in_progress_destroy)) {
+ /*
+ * Store to resize_target is before read resize_initiated as guaranteed
+ * by either cmpxchg or _uatomic_xchg_monotonic_increase.
+ */
+ if (!uatomic_load(&ht->resize_initiated, CMM_RELAXED)) {
+ if (uatomic_load(&ht->in_progress_destroy, CMM_RELAXED)) {
return;
}
- work = malloc(sizeof(*work));
+ work = ht->alloc->malloc(ht->alloc->state, sizeof(*work));
if (work == NULL) {
dbg_printf("error allocating resize work, bailing out\n");
return;
work->ht = ht;
urcu_workqueue_queue_work(cds_lfht_workqueue,
&work->work, do_resize_cb);
- CMM_STORE_SHARED(ht->resize_initiated, 1);
+ uatomic_store(&ht->resize_initiated, 1, CMM_RELAXED);
}
}
projects / urcu.git / blobdiff