make emergency trimming optional, disabled by default

p2p/net/connmgr/connmgr.go

@@ -129,8 +129,12 @@ func NewConnManager(low, hi int, opts ...Option) (*BasicConnMgr, error) {
 	}
 	cm.ctx, cm.cancel = context.WithCancel(context.Background())
 
-	// When we're running low on memory, immediately trigger a trim.
-	cm.unregisterWatchdog = watchdog.RegisterPostGCNotifee(cm.memoryEmergency)
+	if cfg.emergencyTrim {
+		// When we're running low on memory, immediately trigger a trim.
+		cm.unregisterWatchdog = watchdog.RegisterPostGCNotifee(cm.memoryEmergency)
+	} else {
+		cm.unregisterWatchdog = func() {}
+	}
 
 	decay, _ := NewDecayer(cfg.decayer, cm)
 	cm.decayer = decay

p2p/net/connmgr/options.go

@@ -12,6 +12,7 @@ type config struct {
 	gracePeriod   time.Duration
 	silencePeriod time.Duration
 	decayer       *DecayerCfg
+	emergencyTrim bool
 }
 
 // Option represents an option for the basic connection manager.
@@ -50,3 +51,11 @@ func WithSilencePeriod(p time.Duration) Option {
 		return nil
 	}
 }
+
+// WithEmergencyTrim is an option to enable trimming connections on memory emergency.
+func WithEmergencyTrim(enable bool) Option {
+	return func(cfg *config) error {
+		cfg.emergencyTrim = enable
+		return nil
+	}
+}