[ltt-dev] [PATCH 6/7] rculfhash: Move key out of struct lfht_test_node

[laijs@cn.fujitsu.com (Lai Jiangshan)]

Make struct lfht_test_node only contains basic field.
Let user take the responsibility to handle the <key>(hash_set)
or <key,value>(hash_map) management and calculation.

Signed-off-by: Lai Jiangshan <laijs at cn.fujitsu.com>
---
 rculfhash.c            |   12 +-----------
 tests/test_urcu_hash.c |   22 +++++++++++++++-------
 urcu/rculfhash.h       |   33 +++------------------------------
 3 files changed, 19 insertions(+), 48 deletions(-)

diff --git a/rculfhash.c b/rculfhash.c
index 6a8c720..a569172 100644
--- a/rculfhash.c
+++ b/rculfhash.c
@@ -267,11 +267,9 @@ struct rcu_table {
  */
 struct cds_lfht {
 	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;
 	/*
 	 * We need to put the work threads offline (QSBR) when taking this
@@ -1336,9 +1334,7 @@ void cds_lfht_create_dummy(struct cds_lfht *ht, unsigned long size)
 	}
 }
 
-struct cds_lfht *_cds_lfht_new(cds_lfht_hash_fct hash_fct,
-			cds_lfht_compare_fct compare_fct,
-			unsigned long hash_seed,
+struct cds_lfht *_cds_lfht_new(cds_lfht_compare_fct compare_fct,
 			unsigned long init_size,
 			unsigned long min_alloc_size,
 			int flags,
@@ -1367,9 +1363,7 @@ struct cds_lfht *_cds_lfht_new(cds_lfht_hash_fct hash_fct,
 	ht = calloc(1, sizeof(struct cds_lfht));
 	assert(ht);
 	ht->flags = flags;
-	ht->hash_fct = hash_fct;
 	ht->compare_fct = compare_fct;
-	ht->hash_seed = hash_seed;
 	ht->cds_lfht_call_rcu = cds_lfht_call_rcu;
 	ht->cds_lfht_synchronize_rcu = cds_lfht_synchronize_rcu;
 	ht->cds_lfht_rcu_read_lock = cds_lfht_rcu_read_lock;
@@ -1435,13 +1429,9 @@ void cds_lfht_next_duplicate(struct cds_lfht *ht, struct cds_lfht_iter *iter)
 {
 	struct cds_lfht_node *node, *next;
 	unsigned long reverse_hash;
-	void *key;
-	size_t key_len;
 
 	node = iter->node;
 	reverse_hash = node->p.reverse_hash;
-	key = node->key;
-	key_len = node->key_len;
 	next = iter->next;
 	node = clear_flag(next);
 
diff --git a/tests/test_urcu_hash.c b/tests/test_urcu_hash.c
index 1cae6d6..2d2ef22 100644
--- a/tests/test_urcu_hash.c
+++ b/tests/test_urcu_hash.c
@@ -109,6 +109,8 @@ struct test_data {
 
 struct lfht_test_node {
 	struct cds_lfht_node node;
+	void *key;
+	unsigned int key_len;
 	/* cache-cold for iteration */
 	struct rcu_head head;
 };
@@ -123,7 +125,8 @@ static inline
 void lfht_test_node_init(struct lfht_test_node *node, void *key,
 			size_t key_len)
 {
-	cds_lfht_node_init(&node->node, key, key_len);
+	node->key = key;
+	node->key_len = key_len;
 }
 
 static inline struct lfht_test_node *
@@ -424,13 +427,18 @@ int __test_compare(void *key1, size_t key1_len,
 static
 int test_compare(struct cds_lfht_node *a, struct cds_lfht_node *b)
 {
-	return __test_compare(a->key, a->key_len, b->key, b->key_len);
+	struct lfht_test_node *u = to_test_node(a);
+	struct lfht_test_node *v = to_test_node(a);
+
+	return __test_compare(u->key, u->key_len, v->key, v->key_len);
 }
 
 static
 int test_match(struct cds_lfht_node *node, void *arg)
 {
-	return !__test_compare(node->key, node->key_len,
+	struct lfht_test_node *test_node = to_test_node(node);
+
+	return !__test_compare(test_node->key, test_node->key_len,
 			arg, sizeof(unsigned long));
 }
 
@@ -447,7 +455,7 @@ void cds_lfht_test_lookup(struct cds_lfht *ht, void *key, size_t key_len,
 static
 void cds_lfht_test_add(struct cds_lfht *ht, struct lfht_test_node *node)
 {
-	unsigned long hash = test_hash(node->node.key, node->node.key_len, TEST_HASH_SEED);
+	unsigned long hash = test_hash(node->key, node->key_len, TEST_HASH_SEED);
 
 	cds_lfht_add(ht, hash, &node->node);
 }
@@ -456,7 +464,7 @@ static
 struct cds_lfht_node *cds_lfht_test_add_unique(struct cds_lfht *ht,
 		struct lfht_test_node *node)
 {
-	unsigned long hash = test_hash(node->node.key, node->node.key_len, TEST_HASH_SEED);
+	unsigned long hash = test_hash(node->key, node->key_len, TEST_HASH_SEED);
 
 	return cds_lfht_add_unique(ht, hash, &node->node);
 }
@@ -465,7 +473,7 @@ static
 struct cds_lfht_node *cds_lfht_test_add_replace(struct cds_lfht *ht,
 		struct lfht_test_node *node)
 {
-	unsigned long hash = test_hash(node->node.key, node->node.key_len, TEST_HASH_SEED);
+	unsigned long hash = test_hash(node->key, node->key_len, TEST_HASH_SEED);
 
 	return cds_lfht_add_replace(ht, hash, &node->node);
 }
@@ -983,7 +991,7 @@ int main(int argc, char **argv)
 	 * thread from the point of view of resize.
 	 */
 	rcu_register_thread();
-	test_ht = cds_lfht_new(test_hash, test_compare, TEST_HASH_SEED,
+	test_ht = cds_lfht_new(test_compare,
 			init_hash_size, min_hash_alloc_size,
 			(opt_auto_resize ? CDS_LFHT_AUTO_RESIZE : 0) |
 			CDS_LFHT_ACCOUNTING, NULL);
diff --git a/urcu/rculfhash.h b/urcu/rculfhash.h
index d4c9209..cd5760e 100644
--- a/urcu/rculfhash.h
+++ b/urcu/rculfhash.h
@@ -47,12 +47,6 @@ struct _cds_lfht_node {
 } __attribute__((aligned(4)));
 
 /*
- * cds_lfht_node: Contains the full key and length required to check for
- * an actual match, and also contains an rcu_head structure that is used
- * by RCU to track a node through a given RCU grace period.  There is an
- * instance of _cds_lfht_node enclosed as a field within each
- * _cds_lfht_node structure.
- *
  * struct cds_lfht_node can be embedded into a structure (as a field).
  * caa_container_of() can be used to get the structure from the struct
  * cds_lfht_node after a lookup.
@@ -60,8 +54,6 @@ struct _cds_lfht_node {
 struct cds_lfht_node {
 	/* cache-hot for iteration */
 	struct _cds_lfht_node p;          /* needs to be first field */
-	void *key;
-	unsigned int key_len;
 };
 
 /* cds_lfht_iter: Used to track state while traversing a hash chain. */
@@ -82,24 +74,11 @@ struct cds_lfht;
  * Ensure reader and writer threads are registered as urcu readers.
  */
 
-typedef unsigned long (*cds_lfht_hash_fct)(void *key, size_t length,
-					unsigned long seed);
 typedef int (*cds_lfht_compare_fct)(struct cds_lfht_node *a,
 		struct cds_lfht_node *b);
 typedef int (*cds_lfht_lookup_fct)(struct cds_lfht_node *node, void *arg);
 
 /*
- * cds_lfht_node_init - initialize a hash table node
- */
-static inline
-void cds_lfht_node_init(struct cds_lfht_node *node, void *key,
-			size_t key_len)
-{
-	node->key = key;
-	node->key_len = key_len;
-}
-
-/*
  * Hash table creation flags.
  */
 enum {
@@ -110,9 +89,7 @@ enum {
 /*
  * _cds_lfht_new - API used by cds_lfht_new wrapper. Do not use directly.
  */
-struct cds_lfht *_cds_lfht_new(cds_lfht_hash_fct hash_fct,
-			cds_lfht_compare_fct compare_fct,
-			unsigned long hash_seed,
+struct cds_lfht *_cds_lfht_new(cds_lfht_compare_fct compare_fct,
 			unsigned long init_size,
 			unsigned long min_alloc_size,
 			int flags,
@@ -129,9 +106,7 @@ struct cds_lfht *_cds_lfht_new(cds_lfht_hash_fct hash_fct,
 
 /*
  * cds_lfht_new - allocate a hash table.
- * @hash_fct: the hashing function.
  * @compare_fct: the key comparison function.
- * @hash_seed: the seed for hash function.
  * @init_size: number of nodes to allocate initially. Must be power of two.
  * @min_alloc_size: the smallest allocation size to use. Must be power of two.
  * @flags: hash table creation flags (can be combined with bitwise or: '|').
@@ -152,15 +127,13 @@ struct cds_lfht *_cds_lfht_new(cds_lfht_hash_fct hash_fct,
  * Threads calling this API need to be registered RCU read-side threads.
  */
 static inline
-struct cds_lfht *cds_lfht_new(cds_lfht_hash_fct hash_fct,
-			cds_lfht_compare_fct compare_fct,
-			unsigned long hash_seed,
+struct cds_lfht *cds_lfht_new(cds_lfht_compare_fct compare_fct,
 			unsigned long init_size,
 			unsigned long min_alloc_size,
 			int flags,
 			pthread_attr_t *attr)
 {
-	return _cds_lfht_new(hash_fct, compare_fct, hash_seed,
+	return _cds_lfht_new(compare_fct,
 			init_size, min_alloc_size, flags,
 			call_rcu, synchronize_rcu, rcu_read_lock,
 			rcu_read_unlock, rcu_thread_offline,
-- 
1.7.4.4