From a862d91790813f186821ae5d6f80202e934c3609 Mon Sep 17 00:00:00 2001
From: Steven Allen <steven@stebalien.com>
Date: Mon, 27 May 2019 14:35:05 -0700
Subject: [PATCH 1/2] feat: improve protocol interning

This used to specify a max size/count but that was only because this logic was
shared between all peerstores (including the on-disk one). Now that:

1. This only applies to the in-memory one.
2. We never actually GC these.

We can just intern indefinitely.
---
 p2p/host/peerstore/pstoremem/protobook.go | 16 +---------------
 1 file changed, 1 insertion(+), 15 deletions(-)

diff --git a/p2p/host/peerstore/pstoremem/protobook.go b/p2p/host/peerstore/pstoremem/protobook.go
index 04cd14591c..3a5550d2b6 100644
--- a/p2p/host/peerstore/pstoremem/protobook.go
+++ b/p2p/host/peerstore/pstoremem/protobook.go
@@ -8,11 +8,6 @@ import (
 	pstore "github.com/libp2p/go-libp2p-peerstore"
 )
 
-const (
-	maxInternedProtocols    = 512
-	maxInternedProtocolSize = 256
-)
-
 type protoSegment struct {
 	sync.RWMutex
 	protocols map[peer.ID]map[string]struct{}
@@ -35,7 +30,7 @@ var _ pstore.ProtoBook = (*memoryProtoBook)(nil)
 
 func NewProtoBook() pstore.ProtoBook {
 	return &memoryProtoBook{
-		interned: make(map[string]string, maxInternedProtocols),
+		interned: make(map[string]string, 256),
 		segments: func() (ret protoSegments) {
 			for i := range ret {
 				ret[i] = &protoSegment{
@@ -48,10 +43,6 @@ func NewProtoBook() pstore.ProtoBook {
 }
 
 func (pb *memoryProtoBook) internProtocol(proto string) string {
-	if len(proto) > maxInternedProtocolSize {
-		return proto
-	}
-
 	// check if it is interned with the read lock
 	pb.lk.RLock()
 	interned, ok := pb.interned[proto]
@@ -71,11 +62,6 @@ func (pb *memoryProtoBook) internProtocol(proto string) string {
 		return interned
 	}
 
-	// if we've filled the table, throw it away and start over
-	if len(pb.interned) >= maxInternedProtocols {
-		pb.interned = make(map[string]string, maxInternedProtocols)
-	}
-
 	pb.interned[proto] = proto
 	return proto
 }

From 5197d8f344f14ead84c85b4ffc3a6c4bb7d520af Mon Sep 17 00:00:00 2001
From: Steven Allen <steven@stebalien.com>
Date: Mon, 27 May 2019 14:41:29 -0700
Subject: [PATCH 2/2] feat: intern agent versions

This also starts taking up a bunch of memory after a while.
---
 p2p/host/peerstore/pstoremem/metadata.go | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/p2p/host/peerstore/pstoremem/metadata.go b/p2p/host/peerstore/pstoremem/metadata.go
index 162bee5087..9adebd8ae9 100644
--- a/p2p/host/peerstore/pstoremem/metadata.go
+++ b/p2p/host/peerstore/pstoremem/metadata.go
@@ -7,6 +7,11 @@ import (
 	pstore "github.com/libp2p/go-libp2p-peerstore"
 )
 
+var internKeys = map[string]bool{
+	"AgentVersion":    true,
+	"ProtocolVersion": true,
+}
+
 type metakey struct {
 	id  peer.ID
 	key string
@@ -15,8 +20,9 @@ type metakey struct {
 type memoryPeerMetadata struct {
 	// store other data, like versions
 	//ds ds.ThreadSafeDatastore
-	ds     map[metakey]interface{}
-	dslock sync.RWMutex
+	ds       map[metakey]interface{}
+	dslock   sync.RWMutex
+	interned map[string]interface{}
 }
 
 var _ pstore.PeerMetadata = (*memoryPeerMetadata)(nil)
@@ -30,6 +36,13 @@ func NewPeerMetadata() pstore.PeerMetadata {
 func (ps *memoryPeerMetadata) Put(p peer.ID, key string, val interface{}) error {
 	ps.dslock.Lock()
 	defer ps.dslock.Unlock()
+	if vals, ok := val.(string); ok && internKeys[key] {
+		if interned, ok := ps.interned[vals]; ok {
+			val = interned
+		} else {
+			ps.interned[vals] = val
+		}
+	}
 	ps.ds[metakey{p, key}] = val
 	return nil
 }