X-Git-Url: http://git.droids-corp.org/?a=blobdiff_plain;f=lib%2Flibrte_hash%2Frte_hash.h;h=ed0673b73b6216995ac1f4e1db8a589efea3627b;hb=8938998a298ab6dbecbe9f5a0f4ebdfdba90862e;hp=dfa542b0179d584cc4eaf9fe596db7888cf28c02;hpb=9d033dac7d7cacca9559e0381f99b4c730e80979;p=dpdk.git

diff --git a/lib/librte_hash/rte_hash.h b/lib/librte_hash/rte_hash.h
index dfa542b017..ed0673b73b 100644
--- a/lib/librte_hash/rte_hash.h
+++ b/lib/librte_hash/rte_hash.h
@@ -39,14 +39,21 @@ extern "C" {
 /** Flag to support reader writer concurrency */
 #define RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY 0x04
 
-/** Flag to indicate the extendabe bucket table feature should be used */
+/** Flag to indicate the extendable 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.
+ */
+#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.
@@ -132,7 +139,12 @@ 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
  */
@@ -150,12 +162,34 @@ rte_hash_reset(struct rte_hash *h);
 int32_t
 rte_hash_count(const struct rte_hash *h);
 
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice
+ *
+ * Return the maximum key value ID that could possibly be returned by
+ * rte_hash_add_key function.
+ *
+ * @param h
+ *  Hash table to query from
+ * @return
+ *   - -EINVAL if parameters are invalid
+ *   - A value indicating the max key ID of key slots present in the table.
+ */
+__rte_experimental
+int32_t
+rte_hash_max_key_id(const struct rte_hash *h);
+
 /**
  * Add a key-value pair to an existing hash table.
  * 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 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.
@@ -178,6 +212,11 @@ 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.
@@ -210,7 +249,9 @@ rte_hash_add_key_with_hash_data(const struct rte_hash *h, const void *key,
  *   - -EINVAL if the parameters are invalid.
  *   - -ENOSPC if there is no space in the hash for this key.
  *   - A positive value that can be used by the caller as an offset into an
- *     array of user data. This value is unique for this key.
+ *     array of user data. This value is unique for this key. This
+ *     unique key id may be larger than the user specified entry count
+ *     when RTE_HASH_EXTRA_FLAGS_MULTI_WRITER_ADD flag is set.
  */
 int32_t
 rte_hash_add_key(const struct rte_hash *h, const void *key);
@@ -232,7 +273,9 @@ rte_hash_add_key(const struct rte_hash *h, const void *key);
  *   - -EINVAL if the parameters are invalid.
  *   - -ENOSPC if there is no space in the hash for this key.
  *   - A positive value that can be used by the caller as an offset into an
- *     array of user data. This value is unique for this key.
+ *     array of user data. This value is unique for this key. This
+ *     unique key ID may be larger than the user specified entry count
+ *     when RTE_HASH_EXTRA_FLAGS_MULTI_WRITER_ADD flag is set.
  */
 int32_t
 rte_hash_add_key_with_hash(const struct rte_hash *h, const void *key, hash_sig_t sig);
@@ -243,10 +286,14 @@ 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 is enabled,
+ * 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.
@@ -268,10 +315,14 @@ 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 is enabled,
+ * 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.
@@ -318,9 +369,12 @@ rte_hash_get_key_with_position(const struct rte_hash *h, const int32_t 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 is enabled,
- * this API must be called, with the key index returned by rte_hash_add_key_xxx
- * APIs, after the key is deleted using rte_hash_del_key_xxx APIs.
+ * 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
@@ -331,7 +385,8 @@ rte_hash_get_key_with_position(const struct rte_hash *h, const int32_t position,
  *   - 0 if freed successfully
  *   - -EINVAL if the parameters are invalid.
  */
-int __rte_experimental
+__rte_experimental
+int
 rte_hash_free_key_with_position(const struct rte_hash *h,
 				const int32_t position);
 
@@ -428,7 +483,7 @@ rte_hash_lookup_with_hash(const struct rte_hash *h,
 
 /**
  * Calc a hash value by key.
- * This operation is not multi-thread safe.
+ * This operation is not multi-process safe.
  *
  * @param h
  *   Hash table to look in.