[PATCH] lib/hash,lib/rcu: feature hidden key count in hash

["Abdullah Ömer Yamaç" <aomeryamac@gmail.com>]

This patch introduce a new API to get the hidden key count in the hash
table if the rcu qsbr is enabled. When using rte_hash_count with rcu
qsbr enabled, it will return the number of elements that are not in the
free queue. Unless rte_rcu_qsbr_dq_reclaim is called, the number of
elements in the defer queue will not be counted and freed. Therefore I
added a new API to get the number of hidden (defer queue) elements
in the hash table. Then the user can calculate the total number of
elements that are available in the hash table.

Signed-off-by: Abdullah Ömer Yamaç <aomeryamac@gmail.com>

---
Cc: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
Cc: Yipeng Wang <yipeng1.wang@intel.com>
Cc: Sameh Gobriel <sameh.gobriel@intel.com>
Cc: Bruce Richardson <bruce.richardson@intel.com>
Cc: Vladimir Medvedkin <vladimir.medvedkin@intel.com>
---
 lib/hash/rte_cuckoo_hash.c |  9 +++++++++
 lib/hash/rte_hash.h        | 13 +++++++++++++
 lib/hash/version.map       |  1 +
 lib/rcu/rte_rcu_qsbr.c     |  8 ++++++++
 lib/rcu/rte_rcu_qsbr.h     | 11 +++++++++++
 lib/rcu/version.map        |  1 +
 6 files changed, 43 insertions(+)

diff --git a/lib/hash/rte_cuckoo_hash.c b/lib/hash/rte_cuckoo_hash.c
index 70456754c4..3553f3efc7 100644
--- a/lib/hash/rte_cuckoo_hash.c
+++ b/lib/hash/rte_cuckoo_hash.c
@@ -555,6 +555,15 @@ rte_hash_max_key_id(const struct rte_hash *h)
 		return h->entries;
 }
 
+int32_t
+rte_hash_dq_count(const struct rte_hash *h)
+{
+	if (h->dq == NULL)
+		return -EINVAL;
+
+	return rte_rcu_qsbr_dq_count(h->dq);
+}
+
 int32_t
 rte_hash_count(const struct rte_hash *h)
 {
diff --git a/lib/hash/rte_hash.h b/lib/hash/rte_hash.h
index 7ecc021111..8ea97e297d 100644
--- a/lib/hash/rte_hash.h
+++ b/lib/hash/rte_hash.h
@@ -193,6 +193,19 @@ rte_hash_free(struct rte_hash *h);
 void
 rte_hash_reset(struct rte_hash *h);
 
+
+/**
+ * Return the number of records in the defer queue of the hash table 
+ * if RCU is enabled.
+ * @param h
+ *  Hash table to query from
+ * @return
+ *   - -EINVAL if parameters are invalid
+ *   - A value indicating how many records were inserted in the table.
+ */
+int32_t
+rte_hash_dq_count(const struct rte_hash *h);
+
 /**
  * Return the number of keys in the hash table
  * @param h
diff --git a/lib/hash/version.map b/lib/hash/version.map
index 6b2afebf6b..7f7b158cf1 100644
--- a/lib/hash/version.map
+++ b/lib/hash/version.map
@@ -9,6 +9,7 @@ DPDK_24 {
 	rte_hash_add_key_with_hash;
 	rte_hash_add_key_with_hash_data;
 	rte_hash_count;
+	rte_hash_dq_count;
 	rte_hash_crc32_alg;
 	rte_hash_crc_set_alg;
 	rte_hash_create;
diff --git a/lib/rcu/rte_rcu_qsbr.c b/lib/rcu/rte_rcu_qsbr.c
index bd0b83be0c..89f8da4c4c 100644
--- a/lib/rcu/rte_rcu_qsbr.c
+++ b/lib/rcu/rte_rcu_qsbr.c
@@ -450,6 +450,14 @@ rte_rcu_qsbr_dq_reclaim(struct rte_rcu_qsbr_dq *dq, unsigned int n,
 	return 0;
 }
 
+/**
+ * Return the number of entries in a defer queue.
+ */
+unsigned int rte_rcu_qsbr_dq_count(struct rte_rcu_qsbr_dq *dq)
+{
+	return rte_ring_count(dq->r);
+}
+
 /* Delete a defer queue. */
 int
 rte_rcu_qsbr_dq_delete(struct rte_rcu_qsbr_dq *dq)
diff --git a/lib/rcu/rte_rcu_qsbr.h b/lib/rcu/rte_rcu_qsbr.h
index 23c9f89805..ed5a590edd 100644
--- a/lib/rcu/rte_rcu_qsbr.h
+++ b/lib/rcu/rte_rcu_qsbr.h
@@ -794,6 +794,17 @@ int
 rte_rcu_qsbr_dq_reclaim(struct rte_rcu_qsbr_dq *dq, unsigned int n,
 	unsigned int *freed, unsigned int *pending, unsigned int *available);
 
+/**
+ * Return the number of entries in a defer queue.
+ *
+ * @param dq
+ *   Defer queue.
+ * @return
+ *   The number of entries in the defer queue.
+ */
+unsigned int
+rte_rcu_qsbr_dq_count(struct rte_rcu_qsbr_dq *dq);
+
 /**
  * Delete a defer queue.
  *
diff --git a/lib/rcu/version.map b/lib/rcu/version.map
index 982ffd59d9..f410ab41e7 100644
--- a/lib/rcu/version.map
+++ b/lib/rcu/version.map
@@ -5,6 +5,7 @@ DPDK_24 {
 	rte_rcu_qsbr_dq_create;
 	rte_rcu_qsbr_dq_delete;
 	rte_rcu_qsbr_dq_enqueue;
+	rte_rcu_qsbr_dq_count;
 	rte_rcu_qsbr_dq_reclaim;
 	rte_rcu_qsbr_dump;
 	rte_rcu_qsbr_get_memsize;
-- 
2.34.1