trie: optimize memory allocation

trie/committer.go

@@ -57,32 +57,26 @@ func (c *committer) commit(path []byte, n node, parallel bool) node {
 	// Commit children, then parent, and remove the dirty flag.
 	switch cn := n.(type) {
 	case *shortNode:
-		// Commit child
-		collapsed := cn.copy()
-
 		// If the child is fullNode, recursively commit,
 		// otherwise it can only be hashNode or valueNode.
 		if _, ok := cn.Val.(*fullNode); ok {
-			collapsed.Val = c.commit(append(path, cn.Key...), cn.Val, false)
+			cn.Val = c.commit(append(path, cn.Key...), cn.Val, false)
 		}
 		// The key needs to be copied, since we're adding it to the
 		// modified nodeset.
-		collapsed.Key = hexToCompact(cn.Key)
-		hashedNode := c.store(path, collapsed)
+		cn.Key = hexToCompact(cn.Key)
+		hashedNode := c.store(path, cn)
 		if hn, ok := hashedNode.(hashNode); ok {
 			return hn
 		}
-		return collapsed
+		return cn
 	case *fullNode:
-		hashedKids := c.commitChildren(path, cn, parallel)
-		collapsed := cn.copy()
-		collapsed.Children = hashedKids
-
-		hashedNode := c.store(path, collapsed)
+		c.commitChildren(path, cn, parallel)
+		hashedNode := c.store(path, cn)
 		if hn, ok := hashedNode.(hashNode); ok {
 			return hn
 		}
-		return collapsed
+		return cn
 	case hashNode:
 		return cn
 	default:
@@ -92,11 +86,10 @@ func (c *committer) commit(path []byte, n node, parallel bool) node {
 }
 
 // commitChildren commits the children of the given fullnode
-func (c *committer) commitChildren(path []byte, n *fullNode, parallel bool) [17]node {
+func (c *committer) commitChildren(path []byte, n *fullNode, parallel bool) {
 	var (
-		wg       sync.WaitGroup
-		nodesMu  sync.Mutex
-		children [17]node
+		wg      sync.WaitGroup
+		nodesMu sync.Mutex
 	)
 	for i := 0; i < 16; i++ {
 		child := n.Children[i]
@@ -106,22 +99,21 @@ func (c *committer) commitChildren(path []byte, n *fullNode, parallel bool) [17]
 		// If it's the hashed child, save the hash value directly.
 		// Note: it's impossible that the child in range [0, 15]
 		// is a valueNode.
-		if hn, ok := child.(hashNode); ok {
-			children[i] = hn
+		if _, ok := child.(hashNode); ok {
 			continue
 		}
 		// Commit the child recursively and store the "hashed" value.
 		// Note the returned node can be some embedded nodes, so it's
 		// possible the type is not hashNode.
 		if !parallel {
-			children[i] = c.commit(append(path, byte(i)), child, false)
+			n.Children[i] = c.commit(append(path, byte(i)), child, false)
 		} else {
 			wg.Add(1)
 			go func(index int) {
 				p := append(path, byte(index))
 				childSet := trienode.NewNodeSet(c.nodes.Owner)
 				childCommitter := newCommitter(childSet, c.tracer, c.collectLeaf)
-				children[index] = childCommitter.commit(p, child, false)
+				n.Children[index] = childCommitter.commit(p, child, false)
 				nodesMu.Lock()
 				c.nodes.MergeSet(childSet)
 				nodesMu.Unlock()
@@ -132,11 +124,6 @@ func (c *committer) commitChildren(path []byte, n *fullNode, parallel bool) [17]
 	if parallel {
 		wg.Wait()
 	}
-	// For the 17th child, it's possible the type is valuenode.
-	if n.Children[16] != nil {
-		children[16] = n.Children[16]
-	}
-	return children
 }
 
 // store hashes the node n and adds it to the modified nodeset. If leaf collection

trie/hasher.go

@@ -55,70 +55,63 @@ func returnHasherToPool(h *hasher) {
 
 // hash collapses a node down into a hash node, also returning a copy of the
 // original node initialized with the computed hash to replace the original one.
-func (h *hasher) hash(n node, force bool) (hashed node, cached node) {
+func (h *hasher) hash(n node, force bool) node {
 	// Return the cached hash if it's available
 	if hash, _ := n.cache(); hash != nil {
-		return hash, n
+		return hash
 	}
 	// Trie not processed yet, walk the children
 	switch n := n.(type) {
 	case *shortNode:
-		collapsed, cached := h.hashShortNodeChildren(n)
+		collapsed := h.hashShortNodeChildren(n)
 		hashed := h.shortnodeToHash(collapsed, force)
-		// We need to retain the possibly _not_ hashed node, in case it was too
-		// small to be hashed
 		if hn, ok := hashed.(hashNode); ok {
-			cached.flags.hash = hn
+			n.flags.hash = hn
 		} else {
-			cached.flags.hash = nil
+			n.flags.hash = nil
 		}
-		return hashed, cached
+		return hashed
 	case *fullNode:
-		collapsed, cached := h.hashFullNodeChildren(n)
-		hashed = h.fullnodeToHash(collapsed, force)
+		collapsed := h.hashFullNodeChildren(n)
+		hashed := h.fullnodeToHash(collapsed, force)
 		if hn, ok := hashed.(hashNode); ok {
-			cached.flags.hash = hn
+			n.flags.hash = hn
 		} else {
-			cached.flags.hash = nil
+			n.flags.hash = nil
 		}
-		return hashed, cached
+		return hashed
 	default:
 		// Value and hash nodes don't have children, so they're left as were
-		return n, n
+		return n
 	}
 }
 
 // hashShortNodeChildren collapses the short node. The returned collapsed node
 // holds a live reference to the Key, and must not be modified.
-func (h *hasher) hashShortNodeChildren(n *shortNode) (collapsed, cached *shortNode) {
-	// Hash the short node's child, caching the newly hashed subtree
-	collapsed, cached = n.copy(), n.copy()
-	// Previously, we did copy this one. We don't seem to need to actually
-	// do that, since we don't overwrite/reuse keys
-	// cached.Key = common.CopyBytes(n.Key)
+func (h *hasher) hashShortNodeChildren(n *shortNode) *shortNode {
+	var collapsed shortNode
 	collapsed.Key = hexToCompact(n.Key)
-	// Unless the child is a valuenode or hashnode, hash it
 	switch n.Val.(type) {
 	case *fullNode, *shortNode:
-		collapsed.Val, cached.Val = h.hash(n.Val, false)
+		collapsed.Val = h.hash(n.Val, false)
+	default:
+		collapsed.Val = n.Val
 	}
-	return collapsed, cached
+	return &collapsed
 }
 
-func (h *hasher) hashFullNodeChildren(n *fullNode) (collapsed *fullNode, cached *fullNode) {
-	// Hash the full node's children, caching the newly hashed subtrees
-	cached = n.copy()
-	collapsed = n.copy()
+func (h *hasher) hashFullNodeChildren(n *fullNode) *fullNode {
+	var children [17]node
 	if h.parallel {
 		var wg sync.WaitGroup
 		wg.Add(16)
 		for i := 0; i < 16; i++ {
 			go func(i int) {
 				hasher := newHasher(false)
 				if child := n.Children[i]; child != nil {
-					collapsed.Children[i], cached.Children[i] = hasher.hash(child, false)
+					children[i] = hasher.hash(child, false)
 				} else {
-					collapsed.Children[i] = nilValueNode
+					children[i] = nilValueNode
 				}
 				returnHasherToPool(hasher)
 				wg.Done()
@@ -128,13 +121,16 @@ func (h *hasher) hashFullNodeChildren(n *fullNode) (collapsed *fullNode, cached
 	} else {
 		for i := 0; i < 16; i++ {
 			if child := n.Children[i]; child != nil {
-				collapsed.Children[i], cached.Children[i] = h.hash(child, false)
+				children[i] = h.hash(child, false)
 			} else {
-				collapsed.Children[i] = nilValueNode
+				children[i] = nilValueNode
 			}
 		}
 	}
-	return collapsed, cached
+	if n.Children[16] != nil {
+		children[16] = n.Children[16]
+	}
+	return &fullNode{flags: nodeFlag{}, Children: children}
 }
 
 // shortnodeToHash creates a hashNode from a shortNode. The supplied shortnode
@@ -195,10 +191,10 @@ func (h *hasher) hashData(data []byte) hashNode {
 func (h *hasher) proofHash(original node) (collapsed, hashed node) {
 	switch n := original.(type) {
 	case *shortNode:
-		sn, _ := h.hashShortNodeChildren(n)
+		sn := h.hashShortNodeChildren(n)
 		return sn, h.shortnodeToHash(sn, false)
 	case *fullNode:
-		fn, _ := h.hashFullNodeChildren(n)
+		fn := h.hashFullNodeChildren(n)
 		return fn, h.fullnodeToHash(fn, false)
 	default:
 		// Value and hash nodes don't have children, so they're left as were

trie/node.go

@@ -58,15 +58,19 @@ func (n *fullNode) EncodeRLP(w io.Writer) error {
 	return eb.Flush()
 }
 
-func (n *fullNode) copy() *fullNode   { copy := *n; return &copy }
-func (n *shortNode) copy() *shortNode { copy := *n; return &copy }
-
 // nodeFlag contains caching-related metadata about a node.
 type nodeFlag struct {
 	hash  hashNode // cached hash of the node (may be nil)
 	dirty bool     // whether the node has changes that must be written to the database
 }
 
+func (n nodeFlag) copy() nodeFlag {
+	return nodeFlag{
+		hash:  common.CopyBytes(n.hash),
+		dirty: n.dirty,
+	}
+}
+
 func (n *fullNode) cache() (hashNode, bool)  { return n.flags.hash, n.flags.dirty }
 func (n *shortNode) cache() (hashNode, bool) { return n.flags.hash, n.flags.dirty }
 func (n hashNode) cache() (hashNode, bool)   { return nil, true }
@@ -219,7 +223,9 @@ func decodeRef(buf []byte) (node, []byte, error) {
 			err := fmt.Errorf("oversized embedded node (size is %d bytes, want size < %d)", size, hashLen)
 			return nil, buf, err
 		}
-		n, err := decodeNode(nil, buf)
+		// The buffer content has already been copied or is safe to use;
+		// no additional copy is required.
+		n, err := decodeNodeUnsafe(nil, buf)
 		return n, rest, err
 	case kind == rlp.String && len(val) == 0:
 		// empty node