diff --git a/app/dispatcher/default.go b/app/dispatcher/default.go
index 5ffea14f..68e25f7a 100644
--- a/app/dispatcher/default.go
+++ b/app/dispatcher/default.go
@@ -29,7 +29,7 @@ type cachedReader struct {
 func (r *cachedReader) Cache(b *buf.Buffer) {
 	mb, _ := r.reader.ReadMultiBufferWithTimeout(time.Millisecond * 100)
 	if !mb.IsEmpty() {
-		r.cache.WriteMultiBuffer(mb)
+		common.Must(r.cache.WriteMultiBuffer(mb))
 	}
 	common.Must(b.Reset(func(x []byte) (int, error) {
 		return r.cache.Copy(x), nil
diff --git a/app/dns/dns.go b/app/dns/dns.go
index 77633f5f..ae2421ef 100644
--- a/app/dns/dns.go
+++ b/app/dns/dns.go
@@ -1,3 +1,4 @@
+// Package dns is an implementation of core.DNS feature.
 package dns
 
 //go:generate go run $GOPATH/src/v2ray.com/core/common/errors/errorgen/main.go -pkg dns -path App,DNS
diff --git a/app/policy/config.go b/app/policy/config.go
index cf65be9a..c5ecb065 100644
--- a/app/policy/config.go
+++ b/app/policy/config.go
@@ -68,6 +68,7 @@ func (p *Policy) ToCorePolicy() core.Policy {
 	return cp
 }
 
+// ToCorePolicy converts this SystemPolicy to core.SystemPolicy.
 func (p *SystemPolicy) ToCorePolicy() core.SystemPolicy {
 	return core.SystemPolicy{
 		Stats: core.SystemStatsPolicy{
diff --git a/app/policy/manager.go b/app/policy/manager.go
index ebfde0e7..fd04ada0 100644
--- a/app/policy/manager.go
+++ b/app/policy/manager.go
@@ -45,6 +45,7 @@ func (m *Instance) ForLevel(level uint32) core.Policy {
 	return core.DefaultPolicy()
 }
 
+// ForSystem implements core.PolicyManager.
 func (m *Instance) ForSystem() core.SystemPolicy {
 	if m.system == nil {
 		return core.SystemPolicy{}
diff --git a/app/policy/policy.go b/app/policy/policy.go
index 32554afe..492e4596 100644
--- a/app/policy/policy.go
+++ b/app/policy/policy.go
@@ -1,3 +1,4 @@
+// Package policy is an implementation of core.PolicyManager feature.
 package policy
 
 //go:generate go run $GOPATH/src/v2ray.com/core/common/errors/errorgen/main.go -pkg policy -path App,Policy