P2PServer: delete old cached blocks after initial sync

Saves ~20 MB of memory

src/crypto.cpp

@@ -241,21 +241,36 @@ private:
 	std::unordered_map<std::array<uint8_t, HASH_SIZE * 2 + sizeof(size_t)>, hash> public_keys;
 };
 
-static Cache cache;
+static Cache* cache = nullptr;
 
 bool generate_key_derivation(const hash& key1, const hash& key2, hash& derivation)
 {
-	return cache.get_derivation(key1, key2, derivation);
+	return cache->get_derivation(key1, key2, derivation);
 }
 
 bool derive_public_key(const hash& derivation, size_t output_index, const hash& base, hash& derived_key)
 {
-	return cache.get_public_key(derivation, output_index, base, derived_key);
+	return cache->get_public_key(derivation, output_index, base, derived_key);
+}
+
+void init_crypto_cache()
+{
+	if (!cache) {
+		cache = new Cache();
+	}
+}
+
+void destroy_crypto_cache()
+{
+	if (cache) {
+		delete cache;
+		cache = nullptr;
+	}
 }
 
 void clear_crypto_cache()
 {
-	cache.clear();
+	cache->clear();
 }
 
 } // namespace p2pool

src/crypto.h

@@ -23,6 +23,9 @@ void generate_keys(hash& pub, hash& sec);
 bool check_keys(const hash& pub, const hash& sec);
 bool generate_key_derivation(const hash& key1, const hash& key2, hash& derivation);
 bool derive_public_key(const hash& derivation, size_t output_index, const hash& base, hash& derived_key);
+
+void init_crypto_cache();
+void destroy_crypto_cache();
 void clear_crypto_cache();
 
 } // namespace p2pool

src/main.cpp

@@ -16,6 +16,7 @@
  */
 
 #include "common.h"
+#include "crypto.h"
 #include "p2pool.h"
 #include "stratum_server.h"
 #include "p2p_server.h"
@@ -68,10 +69,14 @@ int main(int argc, char* argv[])
 	int result;
 
 	memory_tracking_start();
+
+	p2pool::init_crypto_cache();
 	{
 		p2pool::p2pool pool(argc, argv);
 		result = pool.run();
 	}
+	p2pool::destroy_crypto_cache();
+
 	memory_tracking_stop();
 
 	return result;

src/p2p_server.cpp

@@ -102,14 +102,11 @@ P2PServer::~P2PServer()
 	uv_mutex_destroy(&m_peerListLock);
 	uv_mutex_destroy(&m_broadcastLock);
 	uv_mutex_destroy(&m_missingBlockRequestsLock);
+
+	clear_cached_blocks();
 	uv_rwlock_destroy(&m_cachedBlocksLock);
 
 	delete m_block;
-
-	for (auto it : m_cachedBlocks) {
-		delete it.second;
-	}
-
 	delete m_cache;
 }
 
@@ -124,6 +121,16 @@ void P2PServer::add_cached_block(const PoolBlock& block)
 	m_cachedBlocks.insert({ new_block->m_sidechainId, new_block });
 }
 
+void P2PServer::clear_cached_blocks()
+{
+	WriteLock lock(m_cachedBlocksLock);
+
+	for (auto it : m_cachedBlocks) {
+		delete it.second;
+	}
+	m_cachedBlocks.clear();
+}
+
 void P2PServer::store_in_cache(const PoolBlock& block)
 {
 	if (m_cache && block.m_verified && !block.m_invalid) {

src/p2p_server.h

@@ -49,6 +49,7 @@ public:
 	~P2PServer();
 
 	void add_cached_block(const PoolBlock& block);
+	void clear_cached_blocks();
 	void store_in_cache(const PoolBlock& block);
 
 	void connect_to_peers(const std::string& peer_list);

src/side_chain.cpp

@@ -1552,6 +1552,10 @@ void SideChain::prune_old_blocks()
 
 	if (num_blocks_pruned) {
 		LOGINFO(4, "pruned " << num_blocks_pruned << " old blocks at heights <= " << h);
+
+		// If side-chain started pruning blocks it means the initial sync is complete
+		// It's now safe to delete cached blocks
+		m_pool->p2p_server()->clear_cached_blocks();
 	}
 }
 

tests/src/crypto_tests.cpp

@@ -25,6 +25,8 @@ namespace p2pool {
 
 TEST(crypto, derivation)
 {
+	init_crypto_cache();
+
 	// Run the tests twice to check how crypto cache works
 	for (int i = 0; i < 2; ++i) {
 		std::ifstream f("crypto_tests.txt");
@@ -61,6 +63,8 @@ TEST(crypto, derivation)
 			}
 		} while (!f.eof());
 	}
+
+	destroy_crypto_cache();
 }
 
 }