New upstream version 18.11-rc1

[deb_dpdk.git] / lib / librte_hash / rte_hash.h

diff --git a/lib/librte_hash/rte_hash.h b/lib/librte_hash/rte_hash.h
index 9e7d931..c93d1a1 100644 (file)
--- a/lib/librte_hash/rte_hash.h
+++ b/lib/librte_hash/rte_hash.h
@@ -14,6 +14,8 @@
 #include <stdint.h>
 #include <stddef.h>
 
+#include <rte_compat.h>
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -37,7 +39,27 @@ extern "C" {
 /** Flag to support reader writer concurrency */
 #define RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY 0x04
 
-/** Signature of key that is stored internally. */
+/** Flag to indicate the extendabe bucket table feature should be used */
+#define RTE_HASH_EXTRA_FLAGS_EXT_TABLE 0x08
+
+/** Flag to disable freeing of key index on hash delete.
+ * Refer to rte_hash_del_xxx APIs for more details.
+ * This is enabled by default when RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY_LF
+ * is enabled.
+ */
+#define RTE_HASH_EXTRA_FLAGS_NO_FREE_ON_DEL 0x10
+
+/** Flag to support lock free reader writer concurrency. Both single writer
+ * and multi writer use cases are supported.
+ * Currently, extendable bucket table feature is not supported with
+ * this feature.
+ */
+#define RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY_LF 0x20
+
+/**
+ * The type of hash value of a key.
+ * It should be a value of at least 32bit with fully random pattern.
+ */
 typedef uint32_t hash_sig_t;
 
 /** Type of function that can be used for calculating the hash value. */
@@ -119,7 +141,12 @@ void
 rte_hash_free(struct rte_hash *h);
 
 /**
- * Reset all hash structure, by zeroing all entries
+ * Reset all hash structure, by zeroing all entries.
+ * When RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY_LF is enabled,
+ * it is application's responsibility to make sure that
+ * none of the readers are referencing the hash table
+ * while calling this API.
+ *
  * @param h
  *   Hash table to reset
  */
@@ -143,6 +170,11 @@ rte_hash_count(const struct rte_hash *h);
  * and should only be called from one thread by default.
  * Thread safety can be enabled by setting flag during
  * table creation.
+ * If the key exists already in the table, this API updates its value
+ * with 'data' passed in this API. It is the responsibility of
+ * the application to manage any memory associated with the old value.
+ * The readers might still be using the old value even after this API
+ * has returned.
  *
  * @param h
  *   Hash table to add the key to.
@@ -165,6 +197,11 @@ rte_hash_add_key_data(const struct rte_hash *h, const void *key, void *data);
  * and should only be called from one thread by default.
  * Thread safety can be enabled by setting flag during
  * table creation.
+ * If the key exists already in the table, this API updates its value
+ * with 'data' passed in this API. It is the responsibility of
+ * the application to manage any memory associated with the old value.
+ * The readers might still be using the old value even after this API
+ * has returned.
  *
  * @param h
  *   Hash table to add the key to.
@@ -230,6 +267,14 @@ rte_hash_add_key_with_hash(const struct rte_hash *h, const void *key, hash_sig_t
  * and should only be called from one thread by default.
  * Thread safety can be enabled by setting flag during
  * table creation.
+ * If RTE_HASH_EXTRA_FLAGS_NO_FREE_ON_DEL or
+ * RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY_LF is enabled,
+ * the key index returned by rte_hash_add_key_xxx APIs will not be
+ * freed by this API. rte_hash_free_key_with_position API must be called
+ * additionally to free the index associated with the key.
+ * rte_hash_free_key_with_position API should be called after all
+ * the readers have stopped referencing the entry corresponding to
+ * this key. RCU mechanisms could be used to determine such a state.
  *
  * @param h
  *   Hash table to remove the key from.
@@ -251,6 +296,14 @@ rte_hash_del_key(const struct rte_hash *h, const void *key);
  * and should only be called from one thread by default.
  * Thread safety can be enabled by setting flag during
  * table creation.
+ * If RTE_HASH_EXTRA_FLAGS_NO_FREE_ON_DEL or
+ * RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY_LF is enabled,
+ * the key index returned by rte_hash_add_key_xxx APIs will not be
+ * freed by this API. rte_hash_free_key_with_position API must be called
+ * additionally to free the index associated with the key.
+ * rte_hash_free_key_with_position API should be called after all
+ * the readers have stopped referencing the entry corresponding to
+ * this key. RCU mechanisms could be used to determine such a state.
  *
  * @param h
  *   Hash table to remove the key from.
@@ -289,6 +342,34 @@ int
 rte_hash_get_key_with_position(const struct rte_hash *h, const int32_t position,
                               void **key);
 
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice
+ *
+ * Free a hash key in the hash table given the position
+ * of the key. This operation is not multi-thread safe and should
+ * only be called from one thread by default. Thread safety
+ * can be enabled by setting flag during table creation.
+ * If RTE_HASH_EXTRA_FLAGS_NO_FREE_ON_DEL or
+ * RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY_LF is enabled,
+ * the key index returned by rte_hash_del_key_xxx APIs must be freed
+ * using this API. This API should be called after all the readers
+ * have stopped referencing the entry corresponding to this key.
+ * RCU mechanisms could be used to determine such a state.
+ * This API does not validate if the key is already freed.
+ *
+ * @param h
+ *   Hash table to free the key from.
+ * @param position
+ *   Position returned when the key was deleted.
+ * @return
+ *   - 0 if freed successfully
+ *   - -EINVAL if the parameters are invalid.
+ */
+int __rte_experimental
+rte_hash_free_key_with_position(const struct rte_hash *h,
+                               const int32_t position);
+
 /**
  * Find a key-value pair in the hash table.
  * This operation is multi-thread safe with regarding to other lookup threads.