modules/kmemcached: missing documentation, doc cleanup

doc/modules.rst

@@ -14,3 +14,4 @@ Implemented modules
 .. include:: ../modules/cachectl/README.rst
 .. include:: ../modules/graphite/README.rst
 .. include:: ../modules/ketcd/README.rst
+.. include:: ../modules/kmemcached/README.rst

lib/cache.h

@@ -64,9 +64,9 @@ struct kr_cache_txn {
 /**
  * Open/create cache with provided storage options.
  * @param cache cache structure to be initialized
- * @param api Storage engine
- * @param storage_opts Storage-specific options (may be NULL for default)
- * @param mm Memory context.
+ * @param api   storage engine API
+ * @param opts  storage-specific options (may be NULL for default)
+ * @param mm    memory context.
  * @return 0 or an error code
  */
 int kr_cache_open(struct kr_cache *cache, const namedb_api_t *api, void *opts, mm_ctx_t *mm);

lib/generic/lru.h

@@ -97,7 +97,7 @@ struct lru_hash_base {
 	char slots[];
 };
 
-/** @breif User-defined hashtable. */
+/** @brief User-defined hashtable. */
 #define lru_hash(type) \
 struct { \
 	lru_hash_struct \
@@ -155,9 +155,9 @@ static inline void *lru_slot_set(struct lru_hash_base *lru, const char *key, uin
  * @param table hash table
  * @param max_slots number of slots
  */
-#define lru_init(table, max_size) \
- (memset((table), 0, sizeof(*table) + (max_size) * sizeof((table)->slots[0])), \
-  (table)->stride = sizeof((table)->slots[0]), (table)->size = (max_size))
+#define lru_init(table, max_slots) \
+ (memset((table), 0, sizeof(*table) + (max_slots) * sizeof((table)->slots[0])), \
+  (table)->stride = sizeof((table)->slots[0]), (table)->size = (max_slots))
 
 /**
  * @brief Free all keys and evict all values.

modules/kmemcached/README.rst

+Memcached cache storage
+-----------------------
+
+Module providing a cache storage backend for memcached_, which makes a good fit for
+making a shared cache between resolvers.
+
+After loading you can see the storage backend registered and useable.
+
+.. code-block:: lua
+
+	> modules.load 'kmemcached'
+	> cache.backends()
+	[memcached://] => true
+
+And you can use it right away, see the `libmemcached configuration`_ reference for configuration string
+options, the most essential ones are `--SERVER` or `--SOCKET`. Here's an example for connecting to UNIX socket.
+
+.. code-block:: lua
+
+	> cache.storage = 'memcached://--SOCKET="/var/sock/memcached"'
+
+.. note:: The memcached_ instance **MUST** support binary protocol, in order to make it work with binary keys. You can pass other options to the configuration string for performance tuning.
+
+.. warning:: The memcached_ server is responsible for evicting entries out of cache, the pruning function is not implemented, and neither is aborting write transactions.
+
+Build resolver shared cache
+^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+The memcached_ takes care of the data replication and fail over, you can add multiple servers at once.
+
+.. code-block:: lua
+
+	> cache.storage = 'memcached://--SOCKET="/var/sock/memcached" --SERVER=192.168.1.1 --SERVER=cache2.domain'
+
+Dependencies
+^^^^^^^^^^^^
+
+Depends on the libmemcached_ library.
+
+.. _memcached: http://memcached.org/
+.. _libmemcached: http://libmemcached.org/libMemcached.html
+.. _`libmemcached configuration`: http://docs.libmemcached.org/libmemcached_configuration.html#description