resolve comments

Author: ping-ke

ethereum/pow/ethpow.py

@@ -36,7 +36,7 @@ def hashimoto_slow(
     hashimoto = hashimoto_slow
 elif ETHASH_LIB == "pyethash":
 
-    @lru_cache(2)
+    @lru_cache(10)
     def calculate_cache(n):
         return pyethash.mkcache_bytes(n * EPOCH_LENGTH)
 

quarkchain/cluster/shard_db_operator.py

@@ -332,6 +332,11 @@ def put_minor_block(self, m_block, x_shard_receive_tx_list):
         self.height_to_minor_block_hashes.setdefault(m_block.header.height, set()).add(
             m_block.header.get_hash()
         )
+        
+        # remove the oldest minor block hash from the height_to_minor_block_hashes
+        # if the height is greater than 4096
+        # this is to prevent the height_to_minor_block_hashes from growing indefinitely
+        # and to keep the memory usage in check
         if m_block.header.height - 4096 in self.height_to_minor_block_hashes:
             del self.height_to_minor_block_hashes[
                 m_block.header.height - 4096