* operation.
* - The resize operation for larger tables (and available through an
* API) allows both expanding and shrinking the hash table.
- * - Per-CPU Split-counters are used to keep track of the number of
+ * - Split-counters are used to keep track of the number of
* nodes within the hash table for automatic resize triggering.
* - Resize operation initiated by long chain detection is executed by a
* call_rcu thread, which keeps lock-freedom of add and remove.
#endif
/*
- * Per-CPU split-counters lazily update the global counter each 1024
+ * Split-counters lazily update the global counter each 1024
* addition/removal. It automatically keeps track of resize required.
* We use the bucket length as indicator for need to expand for small
* tables and machines lacking per-cpu data suppport.
struct rcu_table t;
cds_lfht_hash_fct hash_fct;
cds_lfht_compare_fct compare_fct;
+ unsigned long min_alloc_order;
+ unsigned long min_alloc_size;
unsigned long hash_seed;
int flags;
/*
void (*cds_lfht_rcu_unregister_thread)(void);
pthread_attr_t *resize_attr; /* Resize threads attributes */
long count; /* global approximate item count */
- struct ht_items_count *percpu_count; /* per-cpu item count */
+ struct ht_items_count *split_count; /* split item count */
};
struct rcu_resize_work {
* In the unfortunate event the number of CPUs reported would be
* inaccurate, we use modulo arithmetic on the number of CPUs we got.
*/
-#if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF)
+#if defined(HAVE_SYSCONF)
static
void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size,
unsigned long count);
static long nr_cpus_mask = -1;
+static long split_count_mask = -1;
+
+static void ht_init_nr_cpus_mask(void)
+{
+ long maxcpus;
+
+ maxcpus = sysconf(_SC_NPROCESSORS_CONF);
+ if (maxcpus <= 0) {
+ nr_cpus_mask = -2;
+ return;
+ }
+ /*
+ * round up number of CPUs to next power of two, so we
+ * can use & for modulo.
+ */
+ maxcpus = 1UL << get_count_order_ulong(maxcpus);
+ nr_cpus_mask = maxcpus - 1;
+}
static
-struct ht_items_count *alloc_per_cpu_items_count(void)
+struct ht_items_count *alloc_split_items_count(void)
{
struct ht_items_count *count;
- switch (nr_cpus_mask) {
- case -2:
- return NULL;
- case -1:
- {
- long maxcpus;
-
- maxcpus = sysconf(_SC_NPROCESSORS_CONF);
- if (maxcpus <= 0) {
- nr_cpus_mask = -2;
- return NULL;
- }
- /*
- * round up number of CPUs to next power of two, so we
- * can use & for modulo.
- */
- maxcpus = 1UL << get_count_order_ulong(maxcpus);
- nr_cpus_mask = maxcpus - 1;
- }
- /* Fall-through */
- default:
- return calloc(nr_cpus_mask + 1, sizeof(*count));
+ if (nr_cpus_mask == -1) {
+ ht_init_nr_cpus_mask();
+ split_count_mask = nr_cpus_mask;
}
+
+ if (split_count_mask < 0)
+ return NULL;
+ else
+ return calloc(split_count_mask + 1, sizeof(*count));
}
static
-void free_per_cpu_items_count(struct ht_items_count *count)
+void free_split_items_count(struct ht_items_count *count)
{
poison_free(count);
}
+#if defined(HAVE_SCHED_GETCPU)
static
-int ht_get_cpu(void)
+int ht_get_split_count_index(unsigned long hash)
{
int cpu;
- assert(nr_cpus_mask >= 0);
+ assert(split_count_mask >= 0);
cpu = sched_getcpu();
if (unlikely(cpu < 0))
- return cpu;
+ return hash & split_count_mask;
else
- return cpu & nr_cpus_mask;
+ return cpu & split_count_mask;
}
+#else /* #if defined(HAVE_SCHED_GETCPU) */
+static
+int ht_get_split_count_index(unsigned long hash)
+{
+ return hash & split_count_mask;
+}
+#endif /* #else #if defined(HAVE_SCHED_GETCPU) */
static
-void ht_count_add(struct cds_lfht *ht, unsigned long size)
+void ht_count_add(struct cds_lfht *ht, unsigned long size, unsigned long hash)
{
- unsigned long percpu_count;
- int cpu;
+ unsigned long split_count;
+ int index;
- if (unlikely(!ht->percpu_count))
- return;
- cpu = ht_get_cpu();
- if (unlikely(cpu < 0))
+ if (unlikely(!ht->split_count))
return;
- percpu_count = uatomic_add_return(&ht->percpu_count[cpu].add, 1);
- if (unlikely(!(percpu_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))) {
+ index = ht_get_split_count_index(hash);
+ split_count = uatomic_add_return(&ht->split_count[index].add, 1);
+ if (unlikely(!(split_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))) {
long count;
- dbg_printf("add percpu %lu\n", percpu_count);
+ dbg_printf("add split count %lu\n", split_count);
count = uatomic_add_return(&ht->count,
1UL << COUNT_COMMIT_ORDER);
/* If power of 2 */
}
static
-void ht_count_del(struct cds_lfht *ht, unsigned long size)
+void ht_count_del(struct cds_lfht *ht, unsigned long size, unsigned long hash)
{
- unsigned long percpu_count;
- int cpu;
+ unsigned long split_count;
+ int index;
- if (unlikely(!ht->percpu_count))
- return;
- cpu = ht_get_cpu();
- if (unlikely(cpu < 0))
+ if (unlikely(!ht->split_count))
return;
- percpu_count = uatomic_add_return(&ht->percpu_count[cpu].del, 1);
- if (unlikely(!(percpu_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))) {
+ index = ht_get_split_count_index(hash);
+ split_count = uatomic_add_return(&ht->split_count[index].del, 1);
+ if (unlikely(!(split_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))) {
long count;
- dbg_printf("del percpu %lu\n", percpu_count);
+ dbg_printf("del split count %lu\n", split_count);
count = uatomic_add_return(&ht->count,
-(1UL << COUNT_COMMIT_ORDER));
/* If power of 2 */
* Don't shrink table if the number of nodes is below a
* certain threshold.
*/
- if (count < (1UL << COUNT_COMMIT_ORDER) * (nr_cpus_mask + 1))
+ if (count < (1UL << COUNT_COMMIT_ORDER) * (split_count_mask + 1))
return;
cds_lfht_resize_lazy_count(ht, size,
count >> (CHAIN_LEN_TARGET - 1));
}
}
-#else /* #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */
+#else /* #if defined(HAVE_SYSCONF) */
static const long nr_cpus_mask = -2;
+static const long split_count_mask = -2;
static
-struct ht_items_count *alloc_per_cpu_items_count(void)
+struct ht_items_count *alloc_split_items_count(void)
{
return NULL;
}
static
-void free_per_cpu_items_count(struct ht_items_count *count)
+void free_split_items_count(struct ht_items_count *count)
{
}
static
-void ht_count_add(struct cds_lfht *ht, unsigned long size)
+void ht_count_add(struct cds_lfht *ht, unsigned long size, unsigned long hash)
{
}
static
-void ht_count_del(struct cds_lfht *ht, unsigned long size)
+void ht_count_del(struct cds_lfht *ht, unsigned long size, unsigned long hash)
{
}
-#endif /* #else #if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF) */
+#endif /* #else #if defined(HAVE_SYSCONF) */
static
assert(size > 0);
index = hash & (size - 1);
+
+ if (index < ht->min_alloc_size) {
+ dbg_printf("lookup hash %lu index %lu order 0 aridx 0\n",
+ hash, index);
+ return &ht->t.tbl[0]->nodes[index];
+ }
/*
* equivalent to get_count_order_ulong(index + 1), but optimizes
* away the non-existing 0 special-case for
* get_count_order_ulong.
*/
order = fls_ulong(index);
-
dbg_printf("lookup hash %lu index %lu order %lu aridx %lu\n",
- hash, index, order, index & (!order ? 0 : ((1UL << (order - 1)) - 1)));
-
- return &ht->t.tbl[order]->nodes[index & (!order ? 0 : ((1UL << (order - 1)) - 1))];
+ hash, index, order, index & ((1UL << (order - 1)) - 1));
+ return &ht->t.tbl[order]->nodes[index & ((1UL << (order - 1)) - 1)];
}
/*
{
unsigned long j;
- assert(i > 0);
+ assert(i > ht->min_alloc_order);
ht->cds_lfht_rcu_read_lock();
for (j = start; j < start + len; j++) {
struct cds_lfht_node *new_node =
dbg_printf("init table: first_order %lu last_order %lu\n",
first_order, last_order);
- assert(first_order > 0);
+ assert(first_order > ht->min_alloc_order);
for (i = first_order; i <= last_order; i++) {
unsigned long len;
{
unsigned long j;
- assert(i > 0);
+ assert(i > ht->min_alloc_order);
ht->cds_lfht_rcu_read_lock();
for (j = start; j < start + len; j++) {
struct cds_lfht_node *fini_node =
dbg_printf("fini table: first_order %lu last_order %lu\n",
first_order, last_order);
- assert(first_order > 0);
+ assert(first_order > ht->min_alloc_order);
for (i = last_order; i >= first_order; i--) {
unsigned long len;
struct _cds_lfht_node *prev, *node;
unsigned long order, len, i, j;
- ht->t.tbl[0] = calloc(1, sizeof(struct _cds_lfht_node));
+ ht->t.tbl[0] = calloc(1, ht->min_alloc_size * sizeof(struct _cds_lfht_node));
assert(ht->t.tbl[0]);
dbg_printf("create dummy: order %lu index %lu hash %lu\n", 0, 0, 0);
for (order = 1; order < get_count_order_ulong(size) + 1; order++) {
len = 1UL << (order - 1);
- ht->t.tbl[order] = calloc(1, len * sizeof(struct _cds_lfht_node));
- assert(ht->t.tbl[order]);
+ if (order <= ht->min_alloc_order) {
+ ht->t.tbl[order] = (struct rcu_level *) (ht->t.tbl[0]->nodes + len);
+ } else {
+ ht->t.tbl[order] = calloc(1, len * sizeof(struct _cds_lfht_node));
+ assert(ht->t.tbl[order]);
+ }
i = 0;
prev = ht->t.tbl[i]->nodes;
cds_lfht_compare_fct compare_fct,
unsigned long hash_seed,
unsigned long init_size,
+ unsigned long min_alloc_size,
int flags,
void (*cds_lfht_call_rcu)(struct rcu_head *head,
void (*func)(struct rcu_head *head)),
struct cds_lfht *ht;
unsigned long order;
+ /* min_alloc_size must be power of two */
+ if (!min_alloc_size || (min_alloc_size & (min_alloc_size - 1)))
+ return NULL;
/* init_size must be power of two */
- if (init_size && (init_size & (init_size - 1)))
+ if (!init_size || (init_size & (init_size - 1)))
return NULL;
+ min_alloc_size = max(min_alloc_size, MIN_TABLE_SIZE);
+ init_size = max(init_size, min_alloc_size);
ht = calloc(1, sizeof(struct cds_lfht));
assert(ht);
ht->hash_fct = hash_fct;
ht->cds_lfht_rcu_register_thread = cds_lfht_rcu_register_thread;
ht->cds_lfht_rcu_unregister_thread = cds_lfht_rcu_unregister_thread;
ht->resize_attr = attr;
- ht->percpu_count = alloc_per_cpu_items_count();
+ ht->split_count = alloc_split_items_count();
/* this mutex should not nest in read-side C.S. */
pthread_mutex_init(&ht->resize_mutex, NULL);
ht->flags = flags;
- order = get_count_order_ulong(max(init_size, MIN_TABLE_SIZE));
+ order = get_count_order_ulong(init_size);
ht->t.resize_target = 1UL << order;
cds_lfht_create_dummy(ht, 1UL << order);
ht->t.size = 1UL << order;
+ ht->min_alloc_size = min_alloc_size;
+ ht->min_alloc_order = get_count_order_ulong(min_alloc_size);
return ht;
}
size = rcu_dereference(ht->t.size);
_cds_lfht_add(ht, size, node, NULL, 0);
- ht_count_add(ht, size);
+ ht_count_add(ht, size, hash);
}
struct cds_lfht_node *cds_lfht_add_unique(struct cds_lfht *ht,
size = rcu_dereference(ht->t.size);
_cds_lfht_add(ht, size, node, &iter, 0);
if (iter.node == node)
- ht_count_add(ht, size);
+ ht_count_add(ht, size, hash);
return iter.node;
}
for (;;) {
_cds_lfht_add(ht, size, node, &iter, 0);
if (iter.node == node) {
- ht_count_add(ht, size);
+ ht_count_add(ht, size, hash);
return NULL;
}
int cds_lfht_del(struct cds_lfht *ht, struct cds_lfht_iter *iter)
{
- unsigned long size;
+ unsigned long size, hash;
int ret;
size = rcu_dereference(ht->t.size);
ret = _cds_lfht_del(ht, size, iter->node, 0);
- if (!ret)
- ht_count_del(ht, size);
+ if (!ret) {
+ hash = bit_reverse_ulong(iter->node->p.reverse_hash);
+ ht_count_del(ht, size, hash);
+ }
return ret;
}
bit_reverse_ulong(ht->t.tbl[order]->nodes[i].reverse_hash));
assert(is_dummy(ht->t.tbl[order]->nodes[i].next));
}
- poison_free(ht->t.tbl[order]);
+
+ if (order == ht->min_alloc_order)
+ poison_free(ht->t.tbl[0]);
+ else if (order > ht->min_alloc_order)
+ poison_free(ht->t.tbl[order]);
+ /* Nothing to delete for order < ht->min_alloc_order */
}
return 0;
}
ret = cds_lfht_delete_dummy(ht);
if (ret)
return ret;
- free_per_cpu_items_count(ht->percpu_count);
+ free_split_items_count(ht->split_count);
if (attr)
*attr = ht->resize_attr;
poison_free(ht);
unsigned long nr_dummy = 0;
*approx_before = 0;
- if (nr_cpus_mask >= 0) {
+ if (split_count_mask >= 0) {
int i;
- for (i = 0; i < nr_cpus_mask + 1; i++) {
- *approx_before += uatomic_read(&ht->percpu_count[i].add);
- *approx_before -= uatomic_read(&ht->percpu_count[i].del);
+ for (i = 0; i < split_count_mask + 1; i++) {
+ *approx_before += uatomic_read(&ht->split_count[i].add);
+ *approx_before -= uatomic_read(&ht->split_count[i].del);
}
}
} while (!is_end(node));
dbg_printf("number of dummy nodes: %lu\n", nr_dummy);
*approx_after = 0;
- if (nr_cpus_mask >= 0) {
+ if (split_count_mask >= 0) {
int i;
- for (i = 0; i < nr_cpus_mask + 1; i++) {
- *approx_after += uatomic_read(&ht->percpu_count[i].add);
- *approx_after -= uatomic_read(&ht->percpu_count[i].del);
+ for (i = 0; i < split_count_mask + 1; i++) {
+ *approx_after += uatomic_read(&ht->split_count[i].add);
+ *approx_after -= uatomic_read(&ht->split_count[i].del);
}
}
}
{
unsigned long old_order, new_order;
- new_size = max(new_size, MIN_TABLE_SIZE);
+ new_size = max(new_size, ht->min_alloc_size);
old_order = get_count_order_ulong(old_size);
new_order = get_count_order_ulong(new_size);
dbg_printf("resize from %lu (order %lu) to %lu (order %lu) buckets\n",
void resize_target_update_count(struct cds_lfht *ht,
unsigned long count)
{
- count = max(count, MIN_TABLE_SIZE);
+ count = max(count, ht->min_alloc_size);
uatomic_set(&ht->t.resize_target, count);
}
}
}
-#if defined(HAVE_SCHED_GETCPU) && defined(HAVE_SYSCONF)
+#if defined(HAVE_SYSCONF)
static
void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size,
projects / urcu.git / blobdiff