Merge pull request #578 from Barenboim/master

remove mutex from LRUCache

src/manager/DnsCache.cc

@@ -14,6 +14,7 @@
   limitations under the License.
 
   Authors: Wu Jiaxu ([email protected])
+           Xie Han ([email protected])
 */
 
 #include <stdint.h>
@@ -27,40 +28,30 @@
 
 const DnsCache::DnsHandle *DnsCache::get_inner(const HostPort& host_port, int type)
 {
+	int64_t cur_time = GET_CURRENT_SECOND;
+	std::lock_guard<std::mutex> lock(mutex_);
 	const DnsHandle *handle = cache_pool_.get(host_port);
 
 	if (handle)
 	{
-		int64_t cur_time = GET_CURRENT_SECOND;
-
 		switch (type)
 		{
 		case GET_TYPE_TTL:
 			if (cur_time > handle->value.expire_time)
 			{
-				std::lock_guard<std::mutex> lock(mutex_);
-
-				if (cur_time > handle->value.expire_time)
-				{
-					const_cast<DnsHandle *>(handle)->value.expire_time += TTL_INC;
-					cache_pool_.release(handle);
-					return NULL;
-				}
+				const_cast<DnsHandle *>(handle)->value.expire_time += TTL_INC;
+				cache_pool_.release(handle);
+				return NULL;
 			}
 
 			break;
 
 		case GET_TYPE_CONFIDENT:
 			if (cur_time > handle->value.confident_time)
 			{
-				std::lock_guard<std::mutex> lock(mutex_);
-
-				if (cur_time > handle->value.confident_time)
-				{
-					const_cast<DnsHandle *>(handle)->value.confident_time += CONFIDENT_INC;
-					cache_pool_.release(handle);
-					return NULL;
-				}
+				const_cast<DnsHandle *>(handle)->value.confident_time += CONFIDENT_INC;
+				cache_pool_.release(handle);
+				return NULL;
 			}
 
 			break;
@@ -96,7 +87,6 @@ const DnsCache::DnsHandle *DnsCache::put(const HostPort& host_port,
 		expire_time = cur_time + dns_ttl_default;
 
 	std::lock_guard<std::mutex> lock(mutex_);
-
 	return cache_pool_.put(host_port, {addrinfo, confident_time, expire_time});
 }
 

src/manager/DnsCache.h

@@ -52,11 +52,13 @@ class DnsCache
 	// release handle by get/put
 	void release(DnsHandle *handle)
 	{
+		std::lock_guard<std::mutex> lock(mutex_);
 		cache_pool_.release(handle);
 	}
 
 	void release(const DnsHandle *handle)
 	{
+		std::lock_guard<std::mutex> lock(mutex_);
 		cache_pool_.release(handle);
 	}
 
@@ -65,6 +67,7 @@ class DnsCache
 	//Handle *get(const KEY &key);
 	const DnsHandle *get(const HostPort& host_port)
 	{
+		std::lock_guard<std::mutex> lock(mutex_);
 		return cache_pool_.get(host_port);
 	}
 
@@ -134,6 +137,7 @@ class DnsCache
 	// delete from cache, deleter delay called when all inuse-handle release.
 	void del(const HostPort& key)
 	{
+		std::lock_guard<std::mutex> lock(mutex_);
 		cache_pool_.del(key);
 	}
 

src/util/LRUCache.h

@@ -14,14 +14,14 @@
   limitations under the License.
 
   Authors: Wu Jiaxu ([email protected])
+           Xie Han ([email protected])  -- remove mutex
 */
 
 #ifndef _LRUCACHE_H_
 #define _LRUCACHE_H_
+
 #include <assert.h>
 #include <map>
-#include <mutex>
-//#include <unordered_map>
 
 /**
  * @file   LRUCache.h
@@ -101,8 +101,6 @@ typedef typename Map::const_iterator	MapConstIterator;
 
 	~LRUCache()
 	{
-		std::lock_guard<std::mutex> lock(mutex_);
-
 		// Error if caller has an unreleased handle
 		assert(in_use_.next == &in_use_);
 		for (Handle *e = not_use_.next; e != &not_use_; )
@@ -121,8 +119,6 @@ typedef typename Map::const_iterator	MapConstIterator;
 	// max_size means max cache number of key-value pairs
 	void set_max_size(size_t max_size)
 	{
-		std::lock_guard<std::mutex> lock(mutex_);
-
 		max_size_ = max_size;
 	}
 
@@ -132,8 +128,6 @@ typedef typename Map::const_iterator	MapConstIterator;
 	// Remove all cache that are not actively in use.
 	void prune()
 	{
-		std::lock_guard<std::mutex> lock(mutex_);
-
 		while (not_use_.next != &not_use_)
 		{
 			Handle *e = not_use_.next;
@@ -147,12 +141,7 @@ typedef typename Map::const_iterator	MapConstIterator;
 	// release handle by get/put
 	void release(Handle *handle)
 	{
-		if (handle)
-		{
-			std::lock_guard<std::mutex> lock(mutex_);
-
-			unref(handle);
-		}
+		unref(handle);
 	}
 
 	void release(const Handle *handle)
@@ -164,7 +153,6 @@ typedef typename Map::const_iterator	MapConstIterator;
 	// Need call release when handle no longer needed
 	const Handle *get(const KEY& key)
 	{
-		std::lock_guard<std::mutex> lock(mutex_);
 		MapConstIterator it = cache_map_.find(key);
 
 		if (it != cache_map_.end())
@@ -183,8 +171,6 @@ typedef typename Map::const_iterator	MapConstIterator;
 		Handle *e = new Handle(key, value);
 
 		e->ref = 1;
-		std::lock_guard<std::mutex> lock(mutex_);
-
 		size_++;
 		e->in_cache = true;
 		e->ref++;
@@ -216,7 +202,6 @@ typedef typename Map::const_iterator	MapConstIterator;
 	// delete from cache, deleter delay called when all inuse-handle release.
 	void del(const KEY& key)
 	{
-		std::lock_guard<std::mutex> lock(mutex_);
 		MapConstIterator it = cache_map_.find(key);
 
 		if (it != cache_map_.end())
@@ -280,7 +265,6 @@ typedef typename Map::const_iterator	MapConstIterator;
 		unref(e);
 	}
 
-	std::mutex mutex_;
 	size_t max_size_;
 	size_t size_;