Integrate "reuse claim memory" with node cache. Return claims to claimPool when Node refcnt drops to zero.

claimtrie/node/cache.go

@@ -3,6 +3,7 @@ package node
 import (
 	"container/list"
 	"sync"
+	"sync/atomic"
 
 	"github.com/lbryio/lbcd/claimtrie/change"
 )
@@ -27,8 +28,11 @@ func (nc *Cache) insert(name []byte, n *Node, height int32) {
 	nc.mtx.Lock()
 	defer nc.mtx.Unlock()
 
+	atomic.AddInt32(&n.refcnt, 1)
+
 	existing := nc.nodes[key]
 	if existing != nil {
+		existing.node.Close()
 		existing.node = n
 		existing.height = height
 		existing.changes = nil
@@ -38,8 +42,11 @@ func (nc *Cache) insert(name []byte, n *Node, height int32) {
 
 	for nc.order.Len() >= nc.limit {
 		// TODO: maybe ensure that we don't remove nodes that have a lot of changes?
-		delete(nc.nodes, nc.order.Back().Value.(string))
+		exp := nc.order.Back().Value.(string)
+		expired := nc.nodes[exp]
+		delete(nc.nodes, exp)
 		nc.order.Remove(nc.order.Back())
+		expired.node.Close()
 	}
 
 	element := nc.order.PushFront(key)
@@ -55,6 +62,7 @@ func (nc *Cache) fetch(name []byte, height int32) (*Node, []change.Change, int32
 	existing := nc.nodes[key]
 	if existing != nil && existing.height <= height {
 		nc.order.MoveToFront(existing.element)
+		atomic.AddInt32(&existing.node.refcnt, 1)
 		return existing.node, existing.changes, existing.height
 	}
 	return nil, nil, -1
@@ -84,6 +92,7 @@ func (nc *Cache) drop(names [][]byte) {
 			// we can't roll it backwards because we don't know its previous height value; just toast it
 			delete(nc.nodes, key)
 			nc.order.Remove(existing.element)
+			existing.node.Close()
 		}
 	}
 }
@@ -91,6 +100,9 @@ func (nc *Cache) drop(names [][]byte) {
 func (nc *Cache) clear() {
 	nc.mtx.Lock()
 	defer nc.mtx.Unlock()
+	for _, existing := range nc.nodes {
+		existing.node.Close()
+	}
 	nc.nodes = map[string]*cacheLeaf{}
 	nc.order = list.New()
 	// we'll let the GC sort out the remains...

claimtrie/node/claim.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"strconv"
 	"strings"
+	"sync"
 
 	"github.com/lbryio/lbcd/chaincfg/chainhash"
 	"github.com/lbryio/lbcd/claimtrie/change"
@@ -32,6 +33,12 @@ type Claim struct {
 	Sequence int32  `msgpack:",omitempty"`
 }
 
+func newClaim() interface{} {
+	return &Claim{}
+}
+
+var claimPool = sync.Pool{New: newClaim}
+
 func (c *Claim) setOutPoint(op wire.OutPoint) *Claim {
 	c.OutPoint = op
 	return c

claimtrie/node/hashfork_manager.go

@@ -15,6 +15,7 @@ func (nm *HashV2Manager) computeClaimHashes(name []byte) (*chainhash.Hash, int32
 	if err != nil || n == nil {
 		return nil, 0
 	}
+	defer n.Close()
 
 	n.SortClaimsByBid()
 	claimHashes := make([]*chainhash.Hash, 0, len(n.Claims))

claimtrie/node/manager.go

@@ -78,7 +78,9 @@ func (nm *BaseManager) NodeAt(height int32, name []byte) (*Node, error) {
 		if nm.tempChanges != nil { // making an assumption that we only ever have tempChanges for a single block
 			changes = append(changes, nm.tempChanges[string(name)]...)
 		}
+		old := n
 		n = n.Clone()
+		old.Close()
 		updated, err := nm.updateFromChanges(n, changes, height)
 		if err != nil {
 			if n != nil {

claimtrie/node/node.go

@@ -4,7 +4,7 @@ import (
 	"fmt"
 	"math"
 	"sort"
-	"sync"
+	"sync/atomic"
 
 	"github.com/lbryio/lbcd/claimtrie/change"
 	"github.com/lbryio/lbcd/claimtrie/param"
@@ -16,24 +16,19 @@ type Node struct {
 	Claims      ClaimList // List of all Claims.
 	Supports    ClaimList // List of all Supports, including orphaned ones.
 	SupportSums map[change.ClaimID]int64
+	refcnt      int32
 }
 
 // New returns a new node.
 func New() *Node {
-	return &Node{SupportSums: map[change.ClaimID]int64{}}
+	return &Node{SupportSums: map[change.ClaimID]int64{}, refcnt: 1}
 }
 
 func (n *Node) HasActiveBestClaim() bool {
 	return n.BestClaim != nil && n.BestClaim.Status == Activated
 }
 
-var claimPool = sync.Pool{
-	New: func() interface{} {
-		return &Claim{}
-	},
-}
-
-func (n *Node) Close() {
+func (n *Node) close() {
 	n.BestClaim = nil
 	n.SupportSums = nil
 
@@ -48,6 +43,17 @@ func (n *Node) Close() {
 	n.Supports = nil
 }
 
+func (n *Node) Close() {
+	new := atomic.AddInt32(&n.refcnt, -1)
+	if new < 0 {
+		panic("node refcnt underflow")
+	}
+	if new > 0 {
+		return
+	}
+	n.close()
+}
+
 func (n *Node) ApplyChange(chg change.Change, delay int32) error {
 
 	visibleAt := chg.VisibleHeight
@@ -377,12 +383,12 @@ func (n *Node) Clone() *Node {
 	}
 	clone.Supports = make(ClaimList, len(n.Supports))
 	for i, support := range n.Supports {
-		clone.Supports[i] = &Claim{}
+		clone.Supports[i] = claimPool.Get().(*Claim)
 		*clone.Supports[i] = *support
 	}
 	clone.Claims = make(ClaimList, len(n.Claims))
 	for i, claim := range n.Claims {
-		clone.Claims[i] = &Claim{}
+		clone.Claims[i] = claimPool.Get().(*Claim)
 		*clone.Claims[i] = *claim
 	}
 	clone.TakenOverAt = n.TakenOverAt