X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=rculfhash.c;h=4a611a1718451f229d03ea8d7ea5800b18b633dd;hb=747d725c1dd45d5072e0e411642c4d5c6403b4be;hp=46bfa7ae661439f404518439c7e8e132f5506541;hpb=48f1b16da05a3c5fdabd191e9b765ae812e8b488;p=urcu.git

diff --git a/rculfhash.c b/rculfhash.c
index 46bfa7a..4a611a1 100644
--- a/rculfhash.c
+++ b/rculfhash.c
@@ -187,7 +187,8 @@
 /*
  * Define the minimum table size.
  */
-#define MIN_TABLE_SIZE			1
+#define MIN_TABLE_ORDER			0
+#define MIN_TABLE_SIZE			(1UL << MIN_TABLE_ORDER)
 
 #if (CAA_BITS_PER_LONG == 32)
 #define MAX_TABLE_ORDER			32
@@ -237,28 +238,24 @@ struct ht_items_count {
 	unsigned long add, del;
 } __attribute__((aligned(CAA_CACHE_LINE_SIZE)));
 
-/*
- * rcu_level: Contains the per order-index-level bucket node table. The
- * size of each bucket node table is half the number of hashes contained
- * in this order (except for order 0). The minimum allocation size
- * parameter allows combining the bucket 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.
+ * bucket table pointers.
  */
 struct rcu_table {
 	unsigned long size;	/* always a power of 2, shared (RCU) */
 	unsigned long resize_target;
 	int resize_initiated;
-	struct rcu_level *tbl[MAX_TABLE_ORDER];
+
+	/*
+	 * Contains the per order-index-level bucket node table. The size
+	 * of each bucket node table is half the number of hashes contained
+	 * in this order (except for order 0). The minimum allocation size
+	 * parameter allows combining the bucket node arrays of the lowermost
+	 * levels to improve cache locality for small index orders.
+	 */
+	struct cds_lfht_node *tbl[MAX_TABLE_ORDER];
 };
 
 /*
@@ -268,8 +265,9 @@ struct rcu_table {
  */
 struct cds_lfht {
 	struct rcu_table t;
-	unsigned long min_alloc_order;
-	unsigned long min_alloc_size;
+	unsigned long min_alloc_buckets_order;
+	unsigned long min_nr_alloc_buckets;
+	unsigned long max_nr_buckets;
 	int flags;
 	/*
 	 * We need to put the work threads offline (QSBR) when taking this
@@ -760,15 +758,15 @@ static
 void cds_lfht_alloc_bucket_table(struct cds_lfht *ht, unsigned long order)
 {
 	if (order == 0) {
-		ht->t.tbl[0] = calloc(ht->min_alloc_size,
+		ht->t.tbl[0] = calloc(ht->min_nr_alloc_buckets,
 			sizeof(struct cds_lfht_node));
 		assert(ht->t.tbl[0]);
-	} else if (order > ht->min_alloc_order) {
+	} else if (order > ht->min_alloc_buckets_order) {
 		ht->t.tbl[order] = calloc(1UL << (order -1),
 			sizeof(struct cds_lfht_node));
 		assert(ht->t.tbl[order]);
 	}
-	/* Nothing to do for 0 < order && order <= ht->min_alloc_order */
+	/* Nothing to do for 0 < order && order <= ht->min_alloc_buckets_order */
 }
 
 /*
@@ -781,9 +779,9 @@ void cds_lfht_free_bucket_table(struct cds_lfht *ht, unsigned long order)
 {
 	if (order == 0)
 		poison_free(ht->t.tbl[0]);
-	else if (order > ht->min_alloc_order)
+	else if (order > ht->min_alloc_buckets_order)
 		poison_free(ht->t.tbl[order]);
-	/* Nothing to do for 0 < order && order <= ht->min_alloc_order */
+	/* Nothing to do for 0 < order && order <= ht->min_alloc_buckets_order */
 }
 
 static inline
@@ -792,9 +790,9 @@ struct cds_lfht_node *bucket_at(struct cds_lfht *ht, unsigned long index)
 	unsigned long order;
 
 	if ((__builtin_constant_p(index) && index == 0)
-			|| index < ht->min_alloc_size) {
+			|| index < ht->min_nr_alloc_buckets) {
 		dbg_printf("bucket index %lu order 0 aridx 0\n", index);
-		return &ht->t.tbl[0]->nodes[index];
+		return &ht->t.tbl[0][index];
 	}
 	/*
 	 * equivalent to get_count_order_ulong(index + 1), but optimizes
@@ -804,7 +802,7 @@ struct cds_lfht_node *bucket_at(struct cds_lfht *ht, unsigned long index)
 	order = fls_ulong(index);
 	dbg_printf("bucket index %lu order %lu aridx %lu\n",
 		   index, order, index & ((1UL << (order - 1)) - 1));
-	return &ht->t.tbl[order]->nodes[index & ((1UL << (order - 1)) - 1)];
+	return &ht->t.tbl[order][index & ((1UL << (order - 1)) - 1)];
 }
 
 static inline
@@ -1142,7 +1140,7 @@ void init_table_populate_partition(struct cds_lfht *ht, unsigned long i,
 {
 	unsigned long j, size = 1UL << (i - 1);
 
-	assert(i > ht->min_alloc_order);
+	assert(i > MIN_TABLE_ORDER);
 	ht->cds_lfht_rcu_read_lock();
 	for (j = size + start; j < size + start + len; j++) {
 		struct cds_lfht_node *new_node = bucket_at(ht, j);
@@ -1178,7 +1176,7 @@ void init_table(struct cds_lfht *ht,
 
 	dbg_printf("init table: first_order %lu last_order %lu\n",
 		   first_order, last_order);
-	assert(first_order > ht->min_alloc_order);
+	assert(first_order > MIN_TABLE_ORDER);
 	for (i = first_order; i <= last_order; i++) {
 		unsigned long len;
 
@@ -1240,7 +1238,7 @@ void remove_table_partition(struct cds_lfht *ht, unsigned long i,
 {
 	unsigned long j, size = 1UL << (i - 1);
 
-	assert(i > ht->min_alloc_order);
+	assert(i > MIN_TABLE_ORDER);
 	ht->cds_lfht_rcu_read_lock();
 	for (j = size + start; j < size + start + len; j++) {
 		struct cds_lfht_node *fini_node = bucket_at(ht, j);
@@ -1277,7 +1275,7 @@ void fini_table(struct cds_lfht *ht,
 
 	dbg_printf("fini table: first_order %lu last_order %lu\n",
 		   first_order, last_order);
-	assert(first_order > ht->min_alloc_order);
+	assert(first_order > MIN_TABLE_ORDER);
 	for (i = last_order; i >= first_order; i--) {
 		unsigned long len;
 
@@ -1367,7 +1365,8 @@ void cds_lfht_create_bucket(struct cds_lfht *ht, unsigned long size)
 }
 
 struct cds_lfht *_cds_lfht_new(unsigned long init_size,
-			unsigned long min_alloc_size,
+			unsigned long min_nr_alloc_buckets,
+			unsigned long max_nr_buckets,
 			int flags,
 			void (*cds_lfht_call_rcu)(struct rcu_head *head,
 					void (*func)(struct rcu_head *head)),
@@ -1383,14 +1382,25 @@ struct cds_lfht *_cds_lfht_new(unsigned long init_size,
 	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)))
+	/* min_nr_alloc_buckets must be power of two */
+	if (!min_nr_alloc_buckets || (min_nr_alloc_buckets & (min_nr_alloc_buckets - 1)))
 		return NULL;
+
 	/* init_size must be power of two */
 	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);
+
+	if (!max_nr_buckets)
+		max_nr_buckets = 1UL << (MAX_TABLE_ORDER - 1);
+
+	/* max_nr_buckets must be power of two */
+	if (!max_nr_buckets || (max_nr_buckets & (max_nr_buckets - 1)))
+		return NULL;
+
+	min_nr_alloc_buckets = max(min_nr_alloc_buckets, MIN_TABLE_SIZE);
+	init_size = max(init_size, MIN_TABLE_SIZE);
+	max_nr_buckets = max(max_nr_buckets, min_nr_alloc_buckets);
+	init_size = min(init_size, max_nr_buckets);
 	ht = calloc(1, sizeof(struct cds_lfht));
 	assert(ht);
 	ht->flags = flags;
@@ -1408,8 +1418,9 @@ struct cds_lfht *_cds_lfht_new(unsigned long init_size,
 	pthread_mutex_init(&ht->resize_mutex, NULL);
 	order = get_count_order_ulong(init_size);
 	ht->t.resize_target = 1UL << order;
-	ht->min_alloc_size = min_alloc_size;
-	ht->min_alloc_order = get_count_order_ulong(min_alloc_size);
+	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;
 	cds_lfht_create_bucket(ht, 1UL << order);
 	ht->t.size = 1UL << order;
 	return ht;
@@ -1720,7 +1731,7 @@ void _do_cds_lfht_shrink(struct cds_lfht *ht,
 {
 	unsigned long old_order, new_order;
 
-	new_size = max(new_size, ht->min_alloc_size);
+	new_size = max(new_size, MIN_TABLE_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",
@@ -1768,7 +1779,8 @@ static
 void resize_target_update_count(struct cds_lfht *ht,
 				unsigned long count)
 {
-	count = max(count, ht->min_alloc_size);
+	count = max(count, MIN_TABLE_SIZE);
+	count = min(count, ht->max_nr_buckets);
 	uatomic_set(&ht->t.resize_target, count);
 }
 
@@ -1826,6 +1838,7 @@ void cds_lfht_resize_lazy_grow(struct cds_lfht *ht, unsigned long size, int grow
 {
 	unsigned long target_size = size << growth;
 
+	target_size = min(target_size, ht->max_nr_buckets);
 	if (resize_target_grow(ht, target_size) >= target_size)
 		return;
 
@@ -1843,7 +1856,8 @@ void cds_lfht_resize_lazy_count(struct cds_lfht *ht, unsigned long size,
 {
 	if (!(ht->flags & CDS_LFHT_AUTO_RESIZE))
 		return;
-	count = max(count, ht->min_alloc_size);
+	count = max(count, MIN_TABLE_SIZE);
+	count = min(count, ht->max_nr_buckets);
 	if (count == size)
 		return;		/* Already the right size, no resize needed */
 	if (count > size) {	/* lazy grow */