X-Git-Url: https://git.liburcu.org/?a=blobdiff_plain;ds=sidebyside;f=rculfhash.c;h=d1a17669f9fa176660b9552241808f2760f6bdcc;hb=8ed51e048a8e89b09cca31271d640bbaa521c74a;hp=da37e97d38554c6def88699590be83439385e82f;hpb=b5d6b20fb518bce4a39c256ac89dcb376a5f971a;p=urcu.git

diff --git a/rculfhash.c b/rculfhash.c
index da37e97..d1a1766 100644
--- a/rculfhash.c
+++ b/rculfhash.c
@@ -222,15 +222,37 @@
 /* Value of the end pointer. Should not interact with flags. */
 #define END_VALUE		NULL
 
+/*
+ * ht_items_count: Split-counters counting the number of node addition
+ * and removal in the table. Only used if the CDS_LFHT_ACCOUNTING flag
+ * is set at hash table creation.
+ *
+ * These are free-running counters, never reset to zero. They count the
+ * number of add/remove, and trigger every (1 << COUNT_COMMIT_ORDER)
+ * operations to update the global counter. We choose a power-of-2 value
+ * for the trigger to deal with 32 or 64-bit overflow of the counter.
+ */
 struct ht_items_count {
 	unsigned long add, del;
 } __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
 
+/*
+ * rcu_level: Contains the per order-index-level dummy node table. The
+ * size of each dummy node table is half the number of hashes contained
+ * in this order (except for order 0). The minimum allocation size
+ * parameter allows combining the dummy node arrays of the lowermost
+ * levels to improve cache locality for small index orders.
+ */
 struct rcu_level {
 	/* Note: manually update allocation length when adding a field */
 	struct _cds_lfht_node nodes[0];
 };
 
+/*
+ * rcu_table: Contains the size and desired new size if a resize
+ * operation is in progress, as well as the statically-sized array of
+ * rcu_level pointers.
+ */
 struct rcu_table {
 	unsigned long size;	/* always a power of 2, shared (RCU) */
 	unsigned long resize_target;
@@ -238,6 +260,11 @@ struct rcu_table {
 	struct rcu_level *tbl[MAX_TABLE_ORDER];
 };
 
+/*
+ * cds_lfht: Top-level data structure representing a lock-free hash
+ * table. Defined in the implementation file to make it be an opaque
+ * cookie to users.
+ */
 struct cds_lfht {
 	struct rcu_table t;
 	cds_lfht_hash_fct hash_fct;
@@ -269,11 +296,20 @@ struct cds_lfht {
 	struct ht_items_count *split_count;	/* split item count */
 };
 
+/*
+ * rcu_resize_work: Contains arguments passed to RCU worker thread
+ * responsible for performing lazy resize.
+ */
 struct rcu_resize_work {
 	struct rcu_head head;
 	struct cds_lfht *ht;
 };
 
+/*
+ * partition_resize_work: Contains arguments passed to worker threads
+ * executing the hash table resize on partitions of the hash table
+ * assigned to each processor's worker thread.
+ */
 struct partition_resize_work {
 	pthread_t thread_id;
 	struct cds_lfht *ht;
@@ -454,7 +490,7 @@ unsigned int fls_u32(uint32_t x)
 
 unsigned int fls_ulong(unsigned long x)
 {
-#if (CAA_BITS_PER_lONG == 32)
+#if (CAA_BITS_PER_LONG == 32)
 	return fls_u32(x);
 #else
 	return fls_u64(x);
@@ -568,7 +604,7 @@ int ht_get_split_count_index(unsigned long hash)
 
 	assert(split_count_mask >= 0);
 	cpu = sched_getcpu();
-	if (unlikely(cpu < 0))
+	if (caa_unlikely(cpu < 0))
 		return hash & split_count_mask;
 	else
 		return cpu & split_count_mask;
@@ -587,11 +623,11 @@ void ht_count_add(struct cds_lfht *ht, unsigned long size, unsigned long hash)
 	unsigned long split_count;
 	int index;
 
-	if (unlikely(!ht->split_count))
+	if (caa_unlikely(!ht->split_count))
 		return;
 	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)))) {
+	if (caa_unlikely(!(split_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))) {
 		long count;
 
 		dbg_printf("add split count %lu\n", split_count);
@@ -614,11 +650,11 @@ void ht_count_del(struct cds_lfht *ht, unsigned long size, unsigned long hash)
 	unsigned long split_count;
 	int index;
 
-	if (unlikely(!ht->split_count))
+	if (caa_unlikely(!ht->split_count))
 		return;
 	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)))) {
+	if (caa_unlikely(!(split_count & ((1UL << COUNT_COMMIT_ORDER) - 1)))) {
 		long count;
 
 		dbg_printf("del split count %lu\n", split_count);
@@ -770,12 +806,12 @@ void _cds_lfht_gc_bucket(struct cds_lfht_node *dummy, struct cds_lfht_node *node
 		 */
 		assert(dummy != node);
 		for (;;) {
-			if (unlikely(is_end(iter)))
+			if (caa_unlikely(is_end(iter)))
 				return;
-			if (likely(clear_flag(iter)->p.reverse_hash > node->p.reverse_hash))
+			if (caa_likely(clear_flag(iter)->p.reverse_hash > node->p.reverse_hash))
 				return;
 			next = rcu_dereference(clear_flag(iter)->p.next);
-			if (likely(is_removed(next)))
+			if (caa_likely(is_removed(next)))
 				break;
 			iter_prev = clear_flag(iter);
 			iter = next;
@@ -879,9 +915,9 @@ void _cds_lfht_add(struct cds_lfht *ht,
 		iter = rcu_dereference(iter_prev->p.next);
 		assert(iter_prev->p.reverse_hash <= node->p.reverse_hash);
 		for (;;) {
-			if (unlikely(is_end(iter)))
+			if (caa_unlikely(is_end(iter)))
 				goto insert;
-			if (likely(clear_flag(iter)->p.reverse_hash > node->p.reverse_hash))
+			if (caa_likely(clear_flag(iter)->p.reverse_hash > node->p.reverse_hash))
 				goto insert;
 
 			/* dummy node is the first node of the identical-hash-value chain */
@@ -889,7 +925,7 @@ void _cds_lfht_add(struct cds_lfht *ht,
 				goto insert;
 
 			next = rcu_dereference(clear_flag(iter)->p.next);
-			if (unlikely(is_removed(next)))
+			if (caa_unlikely(is_removed(next)))
 				goto gc_node;
 
 			/* uniquely add */
@@ -979,7 +1015,7 @@ int _cds_lfht_del(struct cds_lfht *ht, unsigned long size,
 		struct cds_lfht_node *new_next;
 
 		next = old;
-		if (unlikely(is_removed(next)))
+		if (caa_unlikely(is_removed(next)))
 			return -ENOENT;
 		if (dummy_removal)
 			assert(is_dummy(next));
@@ -1348,10 +1384,10 @@ struct cds_lfht *_cds_lfht_new(cds_lfht_hash_fct hash_fct,
 	pthread_mutex_init(&ht->resize_mutex, NULL);
 	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);
+	cds_lfht_create_dummy(ht, 1UL << order);
+	ht->t.size = 1UL << order;
 	return ht;
 }
 
@@ -1372,19 +1408,20 @@ void cds_lfht_lookup(struct cds_lfht *ht, void *key, size_t key_len,
 	node = rcu_dereference(dummy_node->p.next);
 	node = clear_flag(node);
 	for (;;) {
-		if (unlikely(is_end(node))) {
+		if (caa_unlikely(is_end(node))) {
 			node = next = NULL;
 			break;
 		}
-		if (unlikely(node->p.reverse_hash > reverse_hash)) {
+		if (caa_unlikely(node->p.reverse_hash > reverse_hash)) {
 			node = next = NULL;
 			break;
 		}
 		next = rcu_dereference(node->p.next);
-		if (likely(!is_removed(next))
+		assert(node == clear_flag(node));
+		if (caa_likely(!is_removed(next))
 		    && !is_dummy(next)
-		    && clear_flag(node)->p.reverse_hash == reverse_hash
-		    && likely(!ht->compare_fct(node->key, node->key_len, key, key_len))) {
+		    && node->p.reverse_hash == reverse_hash
+		    && caa_likely(!ht->compare_fct(node->key, node->key_len, key, key_len))) {
 				break;
 		}
 		node = clear_flag(next);
@@ -1409,18 +1446,18 @@ void cds_lfht_next_duplicate(struct cds_lfht *ht, struct cds_lfht_iter *iter)
 	node = clear_flag(next);
 
 	for (;;) {
-		if (unlikely(is_end(node))) {
+		if (caa_unlikely(is_end(node))) {
 			node = next = NULL;
 			break;
 		}
-		if (unlikely(node->p.reverse_hash > reverse_hash)) {
+		if (caa_unlikely(node->p.reverse_hash > reverse_hash)) {
 			node = next = NULL;
 			break;
 		}
 		next = rcu_dereference(node->p.next);
-		if (likely(!is_removed(next))
+		if (caa_likely(!is_removed(next))
 		    && !is_dummy(next)
-		    && likely(!ht->compare_fct(node->key, node->key_len, key, key_len))) {
+		    && caa_likely(!ht->compare_fct(node->key, node->key_len, key, key_len))) {
 				break;
 		}
 		node = clear_flag(next);
@@ -1436,12 +1473,12 @@ void cds_lfht_next(struct cds_lfht *ht, struct cds_lfht_iter *iter)
 
 	node = clear_flag(iter->next);
 	for (;;) {
-		if (unlikely(is_end(node))) {
+		if (caa_unlikely(is_end(node))) {
 			node = next = NULL;
 			break;
 		}
 		next = rcu_dereference(node->p.next);
-		if (likely(!is_removed(next))
+		if (caa_likely(!is_removed(next))
 		    && !is_dummy(next)) {
 				break;
 		}