[PATCH v2] lib/hash: feature reclaim defer queue

[Abdullah Ömer Yamaç]

This patch adds a new feature to the hash library to allow the user to
reclaim the defer queue. This is useful when the user wants to force
reclaim resources that are not being used. This API is only available
if the RCU is enabled.

Signed-off-by: Abdullah Ömer Yamaç <aomeryamac at gmail.com>
Acked-by: Honnappa Nagarahalli <honnappa.nagarahalli at arm.com>
---
 lib/hash/rte_cuckoo_hash.c | 23 +++++++++++++++++++++++
 lib/hash/rte_hash.h        | 14 ++++++++++++++
 lib/hash/version.map       |  7 +++++++
 3 files changed, 44 insertions(+)

diff --git a/lib/hash/rte_cuckoo_hash.c b/lib/hash/rte_cuckoo_hash.c
index 9cf94645f6..254fa80cc5 100644
--- a/lib/hash/rte_cuckoo_hash.c
+++ b/lib/hash/rte_cuckoo_hash.c
@@ -1588,6 +1588,27 @@ rte_hash_rcu_qsbr_add(struct rte_hash *h, struct rte_hash_rcu_config *cfg)
 	return 0;
 }
 
+int
+rte_hash_rcu_qsbr_dq_reclaim(struct rte_hash *h)
+{
+	int ret;
+
+	if (h->hash_rcu_cfg == NULL || h->dq == NULL) {
+		rte_errno = EINVAL;
+		return -1;
+	}
+
+	ret = rte_rcu_qsbr_dq_reclaim(h->dq, h->hash_rcu_cfg->max_reclaim_size, NULL, NULL, NULL);
+	if (ret != 0) {
+		HASH_LOG(ERR,
+			"%s: could not reclaim the defer queue in hash table",
+				__func__);
+		return -1;
+	}
+
+	return 0;
+}
+
 static inline void
 remove_entry(const struct rte_hash *h, struct rte_hash_bucket *bkt,
 		unsigned int i)
diff --git a/lib/hash/rte_hash.h b/lib/hash/rte_hash.h
index 7ecc021111..c119477d50 100644
--- a/lib/hash/rte_hash.h
+++ b/lib/hash/rte_hash.h
@@ -674,6 +674,21 @@ rte_hash_iterate(const struct rte_hash *h, const void **key, void **data, uint32
  */
 int rte_hash_rcu_qsbr_add(struct rte_hash *h, struct rte_hash_rcu_config *cfg);
 
+/**
+ * Reclaim resources from the defer queue.
+ * This API reclaim the resources from the defer queue if rcu is enabled.
+ *
+ * @param h
+ *   the hash object to reclaim resources
+ * @return
+ *   On success - 0
+ *   On error - 1 with error code set in rte_errno.
+ *   Possible rte_errno codes are:
+ *   - EINVAL - invalid pointer or invalid rcu mode
+ */
+__rte_experimental
+int rte_hash_rcu_qsbr_dq_reclaim(struct rte_hash *h);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/lib/hash/version.map b/lib/hash/version.map
index 6b2afebf6b..cec0e8fc67 100644
--- a/lib/hash/version.map
+++ b/lib/hash/version.map
@@ -48,3 +48,9 @@ DPDK_24 {
 
 	local: *;
 };
+
+EXPERIMENTAL {
+	global:
+
+	rte_hash_rcu_qsbr_dq_reclaim;
+}
\ No newline at end of file
-- 
2.34.1