rculfhash: Make auto resize selectable with flag

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/rculfhash.c b/rculfhash.c
index 44a589b03361a33c7625d1b336f05da77d6b1bca..0c153982a1aac87cf0b785ecc8fe93fcec27fafa 100644 (file)
--- a/rculfhash.c
+++ b/rculfhash.c
@@ -211,6 +211,7 @@ struct cds_lfht {
        cds_lfht_hash_fct hash_fct;
        cds_lfht_compare_fct compare_fct;
        unsigned long hash_seed;
+       int flags;
        pthread_mutex_t resize_mutex;   /* resize mutex: add/del mutex */
        unsigned int in_progress_resize, in_progress_destroy;
        void (*cds_lfht_call_rcu)(struct rcu_head *head,
@@ -577,6 +578,8 @@ void check_resize(struct cds_lfht *ht, struct rcu_table *t,
 {
        unsigned long count;
 
+       if (!(ht->flags & CDS_LFHT_AUTO_RESIZE))
+               return;
        count = uatomic_read(&ht->count);
        /*
         * Use bucket-local length for small table expand and for
@@ -907,6 +910,7 @@ struct cds_lfht *cds_lfht_new(cds_lfht_hash_fct hash_fct,
                        cds_lfht_compare_fct compare_fct,
                        unsigned long hash_seed,
                        unsigned long init_size,
+                       int flags,
                        void (*cds_lfht_call_rcu)(struct rcu_head *head,
                                        void (*func)(struct rcu_head *head)),
                        void (*cds_lfht_synchronize_rcu)(void))
@@ -931,6 +935,7 @@ struct cds_lfht *cds_lfht_new(cds_lfht_hash_fct hash_fct,
        ht->t = calloc(1, sizeof(struct cds_lfht)
                       + (order * sizeof(struct rcu_level *)));
        ht->t->size = 0;
+       ht->flags = flags;
        pthread_mutex_lock(&ht->resize_mutex);
        init_table(ht, ht->t, 0, order);
        pthread_mutex_unlock(&ht->resize_mutex);
@@ -1221,19 +1226,18 @@ unsigned long resize_target_update(struct rcu_table *t,
 }
 
 static
-unsigned long resize_target_update_count(struct rcu_table *t,
-                                  unsigned long count)
+void resize_target_update_count(struct rcu_table *t,
+                               unsigned long count)
 {
        count = max(count, MIN_TABLE_SIZE);
-       return uatomic_set(&t->resize_target, count);
+       uatomic_set(&t->resize_target, count);
 }
 
 void cds_lfht_resize(struct cds_lfht *ht, unsigned long new_size)
 {
        struct rcu_table *t = rcu_dereference(ht->t);
-       unsigned long target_size;
 
-       target_size = resize_target_update_count(t, new_size);
+       resize_target_update_count(t, new_size);
        CMM_STORE_SHARED(t->resize_initiated, 1);
        pthread_mutex_lock(&ht->resize_mutex);
        _do_cds_lfht_resize(ht);
@@ -1279,9 +1283,10 @@ void cds_lfht_resize_lazy_count(struct cds_lfht *ht, struct rcu_table *t,
                                unsigned long count)
 {
        struct rcu_resize_work *work;
-       unsigned long target_size;
 
-       target_size = resize_target_update_count(t, count);
+       if (!(ht->flags & CDS_LFHT_AUTO_RESIZE))
+               return;
+       resize_target_update_count(t, count);
        if (!CMM_LOAD_SHARED(t->resize_initiated)) {
                uatomic_inc(&ht->in_progress_resize);
                cmm_smp_mb();   /* increment resize count before calling it */

diff --git a/tests/test_urcu_hash.c b/tests/test_urcu_hash.c
index fc2cfb286423228c43e96e1b3d27cd29b44b03b9..81201f342110ab819594d546401b84b54d8a5875 100644 (file)
--- a/tests/test_urcu_hash.c
+++ b/tests/test_urcu_hash.c
@@ -697,7 +697,8 @@ int main(int argc, char **argv)
        count_reader = malloc(sizeof(*count_reader) * nr_readers);
        count_writer = malloc(sizeof(*count_writer) * nr_writers);
        test_ht = cds_lfht_new(test_hash, test_compare, 0x42UL,
-                        init_hash_size, call_rcu, synchronize_rcu);
+                       init_hash_size, CDS_LFHT_AUTO_RESIZE,
+                       call_rcu, synchronize_rcu);
        ret = populate_hash();
        assert(!ret);
         err = create_all_cpu_call_rcu_data(0);

diff --git a/urcu/rculfhash.h b/urcu/rculfhash.h
index ad157bb6a66ecb570f28dd1b627ce89e7ca08a44..385a43b56a08c09df194c3c556362ade78a1c6fe 100644 (file)
--- a/urcu/rculfhash.h
+++ b/urcu/rculfhash.h
@@ -72,6 +72,13 @@ void cds_lfht_node_init(struct cds_lfht_node *node, void *key,
        node->key_len = key_len;
 }
 
+/*
+ * Hash table creation flags.
+ */
+enum {
+       CDS_LFHT_AUTO_RESIZE = (1U << 0),
+};
+
 /*
  * cds_lfht_new - allocate a hash table.
  *
@@ -82,6 +89,7 @@ struct cds_lfht *cds_lfht_new(cds_lfht_hash_fct hash_fct,
                        cds_lfht_compare_fct compare_fct,
                        unsigned long hash_seed,
                        unsigned long init_size,
+                       int flags,
                        void (*cds_lfht_call_rcu)(struct rcu_head *head,
                                void (*func)(struct rcu_head *head)),
                        void (*cds_lfht_synchronize_rcu)(void));