X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=rculfhash.c;h=807191593c6e7d7671b7ca6f236657771a7d3f32;hb=d0d8f9aa03e9df3ca61b8c823678e5c3a9640a4d;hp=4f82da4451b48d73ceef111f7e23f26b22330af7;hpb=0dcf48471eda28730279e5ead11e5411d23e3af0;p=urcu.git

diff --git a/rculfhash.c b/rculfhash.c
index 4f82da4..8071915 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
@@ -757,17 +758,43 @@ unsigned long _uatomic_xchg_monotonic_increase(unsigned long *ptr,
 }
 
 static
-struct cds_lfht_node *lookup_bucket(struct cds_lfht *ht, unsigned long size,
-		unsigned long hash)
+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,
+			sizeof(struct cds_lfht_node));
+		assert(ht->t.tbl[0]);
+	} else if (order > ht->min_alloc_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 */
+}
+
+/*
+ * cds_lfht_free_bucket_table() should be called with decreasing order.
+ * When cds_lfht_free_bucket_table(0) is called, it means the whole
+ * lfht is destroyed.
+ */
+static
+void cds_lfht_free_bucket_table(struct cds_lfht *ht, unsigned long order)
 {
-	unsigned long index, order;
+	if (order == 0)
+		poison_free(ht->t.tbl[0]);
+	else if (order > ht->min_alloc_order)
+		poison_free(ht->t.tbl[order]);
+	/* Nothing to do for 0 < order && order <= ht->min_alloc_order */
+}
 
-	assert(size > 0);
-	index = hash & (size - 1);
+static inline
+struct cds_lfht_node *bucket_at(struct cds_lfht *ht, unsigned long index)
+{
+	unsigned long order;
 
-	if (index < ht->min_alloc_size) {
-		dbg_printf("lookup hash %lu index %lu order 0 aridx 0\n",
-			   hash, index);
+	if ((__builtin_constant_p(index) && index == 0)
+			|| index < ht->min_alloc_size) {
+		dbg_printf("bucket index %lu order 0 aridx 0\n", index);
 		return &ht->t.tbl[0]->nodes[index];
 	}
 	/*
@@ -776,11 +803,19 @@ struct cds_lfht_node *lookup_bucket(struct cds_lfht *ht, unsigned long size,
 	 * get_count_order_ulong.
 	 */
 	order = fls_ulong(index);
-	dbg_printf("lookup hash %lu index %lu order %lu aridx %lu\n",
-		   hash, index, order, index & ((1UL << (order - 1)) - 1));
+	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)];
 }
 
+static inline
+struct cds_lfht_node *lookup_bucket(struct cds_lfht *ht, unsigned long size,
+		unsigned long hash)
+{
+	assert(size > 0);
+	return bucket_at(ht, hash & (size - 1));
+}
+
 /*
  * Remove all logically deleted nodes from a bucket up to a certain node key.
  */
@@ -1106,19 +1141,18 @@ static
 void init_table_populate_partition(struct cds_lfht *ht, unsigned long i,
 				   unsigned long start, unsigned long len)
 {
-	unsigned long j;
+	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 = start; j < start + len; j++) {
-		struct cds_lfht_node *new_node = &ht->t.tbl[i]->nodes[j];
-
-		dbg_printf("init populate: i %lu j %lu hash %lu\n",
-			   i, j, (1UL << (i - 1)) + j);
-		new_node->reverse_hash =
-				bit_reverse_ulong((1UL << (i - 1)) + j);
-		_cds_lfht_add(ht, NULL, NULL, 1UL << (i - 1),
-				new_node, NULL, 1);
+	for (j = size + start; j < size + start + len; j++) {
+		struct cds_lfht_node *new_node = bucket_at(ht, j);
+
+		assert(j >= size && j < (size << 1));
+		dbg_printf("init populate: order %lu index %lu hash %lu\n",
+			   i, j, j);
+		new_node->reverse_hash = bit_reverse_ulong(j);
+		_cds_lfht_add(ht, NULL, NULL, size, new_node, NULL, 1);
 	}
 	ht->cds_lfht_rcu_read_unlock();
 }
@@ -1145,7 +1179,7 @@ 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;
 
@@ -1156,8 +1190,7 @@ void init_table(struct cds_lfht *ht,
 		if (CMM_LOAD_SHARED(ht->t.resize_target) < (1UL << i))
 			break;
 
-		ht->t.tbl[i] = calloc(1, len * sizeof(struct cds_lfht_node));
-		assert(ht->t.tbl[i]);
+		cds_lfht_alloc_bucket_table(ht, i);
 
 		/*
 		 * Set all bucket nodes reverse hash values for a level and
@@ -1206,18 +1239,18 @@ static
 void remove_table_partition(struct cds_lfht *ht, unsigned long i,
 			    unsigned long start, unsigned long len)
 {
-	unsigned long j;
+	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 = start; j < start + len; j++) {
-		struct cds_lfht_node *fini_node = &ht->t.tbl[i]->nodes[j];
-
-		dbg_printf("remove entry: i %lu j %lu hash %lu\n",
-			   i, j, (1UL << (i - 1)) + j);
-		fini_node->reverse_hash =
-			bit_reverse_ulong((1UL << (i - 1)) + j);
-		(void) _cds_lfht_del(ht, 1UL << (i - 1), fini_node, 1);
+	for (j = size + start; j < size + start + len; j++) {
+		struct cds_lfht_node *fini_node = bucket_at(ht, j);
+
+		assert(j >= size && j < (size << 1));
+		dbg_printf("remove entry: order %lu index %lu hash %lu\n",
+			   i, j, j);
+		fini_node->reverse_hash = bit_reverse_ulong(j);
+		(void) _cds_lfht_del(ht, size, fini_node, 1);
 	}
 	ht->cds_lfht_rcu_read_unlock();
 }
@@ -1241,11 +1274,11 @@ void fini_table(struct cds_lfht *ht,
 		unsigned long first_order, unsigned long last_order)
 {
 	long i;
-	void *free_by_rcu = NULL;
+	unsigned long free_by_rcu_order = 0;
 
 	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;
 
@@ -1266,8 +1299,8 @@ void fini_table(struct cds_lfht *ht,
 		 * return a logically removed node as insert position.
 		 */
 		ht->cds_lfht_synchronize_rcu();
-		if (free_by_rcu)
-			free(free_by_rcu);
+		if (free_by_rcu_order)
+			cds_lfht_free_bucket_table(ht, free_by_rcu_order);
 
 		/*
 		 * Set "removed" flag in bucket nodes about to be removed.
@@ -1277,16 +1310,16 @@ void fini_table(struct cds_lfht *ht,
 		 */
 		remove_table(ht, i, len);
 
-		free_by_rcu = ht->t.tbl[i];
+		free_by_rcu_order = i;
 
 		dbg_printf("fini new size: %lu\n", 1UL << i);
 		if (CMM_LOAD_SHARED(ht->in_progress_destroy))
 			break;
 	}
 
-	if (free_by_rcu) {
+	if (free_by_rcu_order) {
 		ht->cds_lfht_synchronize_rcu();
-		free(free_by_rcu);
+		cds_lfht_free_bucket_table(ht, free_by_rcu_order);
 	}
 }
 
@@ -1294,40 +1327,41 @@ static
 void cds_lfht_create_bucket(struct cds_lfht *ht, unsigned long size)
 {
 	struct cds_lfht_node *prev, *node;
-	unsigned long order, len, i, j;
+	unsigned long order, len, i;
 
-	ht->t.tbl[0] = calloc(1, ht->min_alloc_size * sizeof(struct cds_lfht_node));
-	assert(ht->t.tbl[0]);
+	cds_lfht_alloc_bucket_table(ht, 0);
 
-	dbg_printf("create bucket: order %lu index %lu hash %lu\n", 0, 0, 0);
-	ht->t.tbl[0]->nodes[0].next = flag_bucket(get_end());
-	ht->t.tbl[0]->nodes[0].reverse_hash = 0;
+	dbg_printf("create bucket: order 0 index 0 hash 0\n");
+	node = bucket_at(ht, 0);
+	node->next = flag_bucket(get_end());
+	node->reverse_hash = 0;
 
 	for (order = 1; order < get_count_order_ulong(size) + 1; order++) {
 		len = 1UL << (order - 1);
-		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]);
-		}
+		cds_lfht_alloc_bucket_table(ht, order);
 
-		i = 0;
-		prev = ht->t.tbl[i]->nodes;
-		for (j = 0; j < len; j++) {
-			if (j & (j - 1)) {	/* Between power of 2 */
-				prev++;
-			} else if (j) {		/* At each power of 2 */
-				i++;
-				prev = ht->t.tbl[i]->nodes;
-			}
+		for (i = 0; i < len; i++) {
+			/*
+			 * Now, we are trying to init the node with the
+			 * hash=(len+i) (which is also a bucket with the
+			 * index=(len+i)) and insert it into the hash table,
+			 * so this node has to be inserted after the bucket
+			 * with the index=(len+i)&(len-1)=i. And because there
+			 * is no other non-bucket node nor bucket node with
+			 * larger index/hash inserted, so the bucket node
+			 * being inserted should be inserted directly linked
+			 * after the bucket node with index=i.
+			 */
+			prev = bucket_at(ht, i);
+			node = bucket_at(ht, len + i);
 
-			node = &ht->t.tbl[order]->nodes[j];
 			dbg_printf("create bucket: order %lu index %lu hash %lu\n",
-				   order, j, j + len);
+				   order, len + i, len + i);
+			node->reverse_hash = bit_reverse_ulong(len + i);
+
+			/* insert after prev */
+			assert(is_bucket(prev->next));
 			node->next = prev->next;
-			assert(is_bucket(node->next));
-			node->reverse_hash = bit_reverse_ulong(j + len);
 			prev->next = flag_bucket(node);
 		}
 	}
@@ -1357,7 +1391,7 @@ struct cds_lfht *_cds_lfht_new(unsigned long init_size,
 	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);
+	init_size = max(init_size, MIN_TABLE_SIZE);
 	ht = calloc(1, sizeof(struct cds_lfht));
 	assert(ht);
 	ht->flags = flags;
@@ -1477,14 +1511,11 @@ void cds_lfht_next(struct cds_lfht *ht, struct cds_lfht_iter *iter)
 
 void cds_lfht_first(struct cds_lfht *ht, struct cds_lfht_iter *iter)
 {
-	struct cds_lfht_node *lookup;
-
 	/*
 	 * Get next after first bucket node. The first bucket node is the
 	 * first node of the linked list.
 	 */
-	lookup = &ht->t.tbl[0]->nodes[0];
-	iter->next = lookup->next;
+	iter->next = bucket_at(ht, 0)->next;
 	cds_lfht_next(ht, iter);
 }
 
@@ -1570,7 +1601,7 @@ int cds_lfht_delete_bucket(struct cds_lfht *ht)
 	unsigned long order, i, size;
 
 	/* Check that the table is empty */
-	node = &ht->t.tbl[0]->nodes[0];
+	node = bucket_at(ht, 0);
 	do {
 		node = clear_flag(node)->next;
 		if (!is_bucket(node))
@@ -1583,23 +1614,16 @@ int cds_lfht_delete_bucket(struct cds_lfht *ht)
 	 */
 	size = ht->t.size;
 	/* Internal sanity check: all nodes left should be bucket */
-	for (order = 0; order < get_count_order_ulong(size) + 1; order++) {
-		unsigned long len;
+	for (i = 0; i < size; i++) {
+		node = bucket_at(ht, i);
+		dbg_printf("delete bucket: index %lu expected hash %lu hash %lu\n",
+			i, i, bit_reverse_ulong(node->reverse_hash));
+		assert(is_bucket(node->next));
+	}
 
-		len = !order ? 1 : 1UL << (order - 1);
-		for (i = 0; i < len; i++) {
-			dbg_printf("delete order %lu i %lu hash %lu\n",
-				order, i,
-				bit_reverse_ulong(ht->t.tbl[order]->nodes[i].reverse_hash));
-			assert(is_bucket(ht->t.tbl[order]->nodes[i].next));
-		}
+	for (order = get_count_order_ulong(size); (long)order >= 0; order--)
+		cds_lfht_free_bucket_table(ht, 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;
 }
 
@@ -1649,7 +1673,7 @@ void cds_lfht_count_nodes(struct cds_lfht *ht,
 	*removed = 0;
 
 	/* Count non-bucket nodes in the table */
-	node = &ht->t.tbl[0]->nodes[0];
+	node = bucket_at(ht, 0);
 	do {
 		next = rcu_dereference(node->next);
 		if (is_removed(next)) {
@@ -1697,7 +1721,7 @@ 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",
@@ -1745,7 +1769,7 @@ 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);
 	uatomic_set(&ht->t.resize_target, count);
 }
 
@@ -1820,7 +1844,7 @@ 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);
 	if (count == size)
 		return;		/* Already the right size, no resize needed */
 	if (count > size) {	/* lazy grow */