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authorPéter Szilágyi <peterke@gmail.com>2018-07-02 17:19:41 +0800
committerPéter Szilágyi <peterke@gmail.com>2018-07-02 20:47:33 +0800
commit319098cc1c5ae6f54a8f05d77c564ff31c828814 (patch)
tree8864cdbcdb554480917bf3d60e7d6429622dad4f /trie/database.go
parenta4a2343cdc1946e38da1aea1476642d1744c1354 (diff)
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trie: fix a temporary memory leak in the memcache
Diffstat (limited to 'trie/database.go')
-rw-r--r--trie/database.go50
1 files changed, 49 insertions, 1 deletions
diff --git a/trie/database.go b/trie/database.go
index 88c6e9cd6..df7fc01ea 100644
--- a/trie/database.go
+++ b/trie/database.go
@@ -466,7 +466,13 @@ func (db *Database) dereference(child common.Hash, parent common.Hash) {
return
}
// If there are no more references to the child, delete it and cascade
- node.parents--
+ if node.parents > 0 {
+ // This is a special cornercase where a node loaded from disk (i.e. not in the
+ // memcache any more) gets reinjected as a new node (short node split into full,
+ // then reverted into short), causing a cached node to have no parents. That is
+ // no problem in itself, but don't make maxint parents out of it.
+ node.parents--
+ }
if node.parents == 0 {
// Remove the node from the flush-list
if child == db.oldest {
@@ -717,3 +723,45 @@ func (db *Database) Size() (common.StorageSize, common.StorageSize) {
var flushlistSize = common.StorageSize((len(db.nodes) - 1) * 2 * common.HashLength)
return db.nodesSize + flushlistSize, db.preimagesSize
}
+
+// verifyIntegrity is a debug method to iterate over the entire trie stored in
+// memory and check whether every node is reachable from the meta root. The goal
+// is to find any errors that might cause memory leaks and or trie nodes to go
+// missing.
+//
+// This method is extremely CPU and memory intensive, only use when must.
+func (db *Database) verifyIntegrity() {
+ // Iterate over all the cached nodes and accumulate them into a set
+ reachable := map[common.Hash]struct{}{{}: {}}
+
+ for child := range db.nodes[common.Hash{}].children {
+ db.accumulate(child, reachable)
+ }
+ // Find any unreachable but cached nodes
+ unreachable := []string{}
+ for hash, node := range db.nodes {
+ if _, ok := reachable[hash]; !ok {
+ unreachable = append(unreachable, fmt.Sprintf("%x: {Node: %v, Parents: %d, Prev: %x, Next: %x}",
+ hash, node.node, node.parents, node.flushPrev, node.flushNext))
+ }
+ }
+ if len(unreachable) != 0 {
+ panic(fmt.Sprintf("trie cache memory leak: %v", unreachable))
+ }
+}
+
+// accumulate iterates over the trie defined by hash and accumulates all the
+// cached children found in memory.
+func (db *Database) accumulate(hash common.Hash, reachable map[common.Hash]struct{}) {
+ // Mark the node reachable if present in the memory cache
+ node, ok := db.nodes[hash]
+ if !ok {
+ return
+ }
+ reachable[hash] = struct{}{}
+
+ // Iterate over all the children and accumulate them too
+ for _, child := range node.childs() {
+ db.accumulate(child, reachable)
+ }
+}