#include <assert.h>
#include <stdio.h>
#include <stdint.h>
+#include <string.h>
#include <urcu.h>
#include <urcu-call-rcu.h>
#include <stdio.h>
#include <pthread.h>
-#define BUCKET_SIZE_RESIZE_THRESHOLD 5
+#define DEBUG /* Test */
+
+#ifdef DEBUG
+#define dbg_printf(args...) printf(args)
+#else
+#define dbg_printf(args...)
+#endif
+
+#define BUCKET_SIZE_RESIZE_THRESHOLD 4
#ifndef max
#define max(a, b) ((a) > (b) ? (a) : (b))
struct rcu_table {
unsigned long size; /* always a power of 2 */
+ unsigned long resize_target;
struct rcu_head head;
struct rcu_ht_node *tbl[0];
};
struct rcu_ht {
struct rcu_table *t; /* shared */
ht_hash_fct hash_fct;
- void *hashseed;
+ ht_compare_fct compare_fct;
+ unsigned long hash_seed;
pthread_mutex_t resize_mutex; /* resize mutex: add/del mutex */
- unsigned long target_size;
void (*ht_call_rcu)(struct rcu_head *head,
void (*func)(struct rcu_head *head));
};
struct rcu_ht *ht;
};
-static
-void ht_resize_lazy(struct rcu_ht *ht, int growth);
-
-static
-void check_resize(struct rcu_ht *ht, unsigned long chain_len)
-{
- if (chain_len >= BUCKET_SIZE_RESIZE_THRESHOLD)
- ht_resize_lazy(ht, chain_len / BUCKET_SIZE_RESIZE_THRESHOLD);
-}
-
/*
* Algorithm to reverse bits in a word by lookup table, extended to
* 64-bit words.
- * ref.
+ * Source:
* http://graphics.stanford.edu/~seander/bithacks.html#BitReverseTable
+ * Originally from Public Domain.
*/
static const uint8_t BitReverseTable256[256] =
#endif
}
+/*
+ * Algorithm to find the log2 of a 32-bit unsigned integer.
+ * source: http://graphics.stanford.edu/~seander/bithacks.html#IntegerLogLookup
+ * Originally from Public Domain.
+ */
+static const char LogTable256[256] =
+{
+#define LT(n) n, n, n, n, n, n, n, n, n, n, n, n, n, n, n, n
+ -1, 0, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3,
+ LT(4), LT(5), LT(5), LT(6), LT(6), LT(6), LT(6),
+ LT(7), LT(7), LT(7), LT(7), LT(7), LT(7), LT(7), LT(7)
+};
+
+uint32_t log2_u32(uint32_t v)
+{
+ uint32_t t, tt;
+
+ if ((tt = (v >> 16)))
+ return (t = (tt >> 8))
+ ? 24 + LogTable256[t]
+ : 16 + LogTable256[tt];
+ else
+ return (t = (v >> 8))
+ ? 8 + LogTable256[t]
+ : LogTable256[v];
+}
+
+static
+void ht_resize_lazy(struct rcu_ht *ht, struct rcu_table *t, int growth);
+
+static
+void check_resize(struct rcu_ht *ht, struct rcu_table *t,
+ uint32_t chain_len)
+{
+ if (chain_len >= BUCKET_SIZE_RESIZE_THRESHOLD)
+ ht_resize_lazy(ht, t, log2_u32(chain_len));
+}
+
static
struct rcu_ht_node *clear_flag(struct rcu_ht_node *node)
{
}
static
-void _uatomic_max(unsigned long *ptr, unsigned long v)
+unsigned long _uatomic_max(unsigned long *ptr, unsigned long v)
{
unsigned long old1, old2;
do {
old2 = old1;
if (old2 >= v)
- break;
+ return old2;
} while ((old1 = uatomic_cmpxchg(ptr, old2, v)) != old2);
+ return v;
}
static
-int _ht_add(struct rcu_ht *ht, struct rcu_table *t, struct rcu_ht_node *node)
+void _ht_add(struct rcu_ht *ht, struct rcu_table *t, struct rcu_ht_node *node)
{
struct rcu_ht_node *iter_prev = NULL, *iter = NULL;
+ if (!t->size)
+ return;
for (;;) {
- unsigned long chain_len = 0;
+ uint32_t chain_len = 0;
iter_prev = rcu_dereference(t->tbl[node->hash & (t->size - 1)]);
assert(iter_prev);
if (iter->reverse_hash < node->reverse_hash)
break;
iter_prev = iter;
- check_resize(ht, ++chain_len);
+ check_resize(ht, t, ++chain_len);
}
/* add in iter_prev->next */
if (is_removed(iter))
continue;
+ assert(node != iter);
node->next = iter;
+ assert(iter_prev != node);
if (uatomic_cmpxchg(&iter_prev->next, iter, node) != iter)
continue;
+ break;
}
}
goto end;
}
/* set deletion flag */
- if ((old = uatomic_cmpxchg(&iter->next, next, flag_removed(next))) != next) {
+ if ((old = uatomic_cmpxchg(&iter->next, next,
+ flag_removed(next))) != next) {
if (old == flag_removed(next)) {
ret = -ENOENT;
goto end;
t->tbl[i]->reverse_hash = bit_reverse_ulong(i);
_ht_add(ht, t, t->tbl[i]);
}
- t->size = end;
+ t->resize_target = t->size = end;
}
struct rcu_ht *ht_new(ht_hash_fct hash_fct,
- void *hashseed,
+ ht_compare_fct compare_fct,
+ unsigned long hash_seed,
unsigned long init_size,
void (*ht_call_rcu)(struct rcu_head *head,
void (*func)(struct rcu_head *head)))
ht = calloc(1, sizeof(struct rcu_ht));
ht->hash_fct = hash_fct;
- ht->hashseed = hashseed;
+ ht->compare_fct = compare_fct;
+ ht->hash_seed = hash_seed;
+ ht->ht_call_rcu = ht_call_rcu;
/* this mutex should not nest in read-side C.S. */
pthread_mutex_init(&ht->resize_mutex, NULL);
ht->t = calloc(1, sizeof(struct rcu_table)
+ (max(init_size, 1) * sizeof(struct rcu_ht_node *)));
ht->t->size = 0;
+ pthread_mutex_lock(&ht->resize_mutex);
init_table(ht, ht->t, 0, max(init_size, 1));
- ht->target_size = ht->t->size;
- ht->ht_call_rcu = ht_call_rcu;
+ pthread_mutex_unlock(&ht->resize_mutex);
return ht;
}
-struct rcu_ht_node *ht_lookup(struct rcu_ht *ht, void *key)
+struct rcu_ht_node *ht_lookup(struct rcu_ht *ht, void *key, size_t key_len)
{
struct rcu_table *t;
struct rcu_ht_node *node;
unsigned long hash, reverse_hash;
- hash = ht->hash_fct(ht->hashseed, key);
+ hash = ht->hash_fct(key, key_len, ht->hash_seed);
reverse_hash = bit_reverse_ulong(hash);
t = rcu_dereference(ht->t);
- cmm_smp_read_barrier_depends(); /* read t before size and table */
node = rcu_dereference(t->tbl[hash & (t->size - 1)]);
for (;;) {
if (unlikely(!node))
node = NULL;
break;
}
- if (node->key == key) {
+ if (!ht->compare_fct(node->key, node->key_len, key, key_len)) {
if (is_removed(rcu_dereference(node->next)))
node = NULL;
break;
return node;
}
-int ht_add(struct rcu_ht *ht, struct rcu_ht_node *node)
+void ht_add(struct rcu_ht *ht, struct rcu_ht_node *node)
{
struct rcu_table *t;
- node->hash = ht->hash_fct(ht->hashseed, node->key);
+ node->hash = ht->hash_fct(node->key, node->key_len, ht->hash_seed);
node->reverse_hash = bit_reverse_ulong((unsigned long) node->hash);
t = rcu_dereference(ht->t);
- cmm_smp_read_barrier_depends(); /* read t before size and table */
- return _ht_add(ht, t, node);
+ _ht_add(ht, t, node);
}
int ht_remove(struct rcu_ht *ht, struct rcu_ht_node *node)
struct rcu_table *t;
t = rcu_dereference(ht->t);
- cmm_smp_read_barrier_depends(); /* read t before size and table */
return _ht_remove(ht, t, node);
}
old_t = ht->t;
old_size = old_t->size;
- new_size = CMM_LOAD_SHARED(ht->target_size);
+ new_size = CMM_LOAD_SHARED(old_t->resize_target);
+ dbg_printf("rculfhash: resize from %lu to %lu buckets\n",
+ old_size, new_size);
if (old_size == new_size)
return;
- new_t = realloc(old_t, sizeof(struct rcu_table)
+ new_t = malloc(sizeof(struct rcu_table)
+ (new_size * sizeof(struct rcu_ht_node *)));
- if (new_size > old_size)
- init_table(ht, new_t, old_size, new_size - old_size);
- cmm_smp_wmb(); /* update content before updating reallocated size */
- CMM_STORE_SHARED(new_t->size, new_size);
- if (new_t != old_t) {
- /* Changing table and size atomically wrt lookups */
- rcu_assign_pointer(ht->t, new_t);
- ht->ht_call_rcu(&old_t->head, ht_free_table_cb);
- }
+ assert(new_size > old_size);
+ memcpy(&new_t->tbl, &old_t->tbl,
+ old_size * sizeof(struct rcu_ht_node *));
+ init_table(ht, new_t, old_size, new_size - old_size);
+ /* Changing table and size atomically wrt lookups */
+ rcu_assign_pointer(ht->t, new_t);
+ ht->ht_call_rcu(&old_t->head, ht_free_table_cb);
}
static
-void resize_target_update(struct rcu_ht *ht, int growth_order)
+unsigned long resize_target_update(struct rcu_table *t,
+ int growth_order)
{
- _uatomic_max(&ht->target_size,
- CMM_LOAD_SHARED(ht->target_size) << growth_order);
+ return _uatomic_max(&t->resize_target,
+ t->size << growth_order);
}
void ht_resize(struct rcu_ht *ht, int growth)
{
- resize_target_update(ht, growth);
- pthread_mutex_lock(&ht->resize_mutex);
- _do_ht_resize(ht);
- pthread_mutex_unlock(&ht->resize_mutex);
+ struct rcu_table *t = rcu_dereference(ht->t);
+ unsigned long target_size;
+
+ target_size = resize_target_update(t, growth);
+ if (t->size < target_size) {
+ pthread_mutex_lock(&ht->resize_mutex);
+ _do_ht_resize(ht);
+ pthread_mutex_unlock(&ht->resize_mutex);
+ }
}
static
}
static
-void ht_resize_lazy(struct rcu_ht *ht, int growth)
+void ht_resize_lazy(struct rcu_ht *ht, struct rcu_table *t, int growth)
{
struct rcu_resize_work *work;
+ unsigned long target_size;
- work = malloc(sizeof(*work));
- work->ht = ht;
- resize_target_update(ht, growth);
- ht->ht_call_rcu(&work->head, do_resize_cb);
+ target_size = resize_target_update(t, growth);
+ if (t->size < target_size) {
+ work = malloc(sizeof(*work));
+ work->ht = ht;
+ ht->ht_call_rcu(&work->head, do_resize_cb);
+ }
}
projects / urcu.git / blobdiff