Index: sys/kern/subr_epoch.c
===================================================================
--- sys/kern/subr_epoch.c
+++ sys/kern/subr_epoch.c
@@ -579,6 +579,17 @@
 	callback(ctx);
 }
 
+void
+epoch_call_drain(epoch_t epoch)
+{
+	int cpu;
+
+	CPU_FOREACH(cpu) {
+		gtaskqueue_drain_all(
+		    (DPCPU_ID_PTR(cpu, epoch_cb_task))->gt_taskqueue);
+	}
+}
+
 static void
 epoch_call_task(void *arg __unused)
 {
Index: sys/sys/epoch.h
===================================================================
--- sys/sys/epoch.h
+++ sys/sys/epoch.h
@@ -70,6 +70,7 @@
 void	epoch_wait(epoch_t epoch);
 void	epoch_wait_preempt(epoch_t epoch);
 void	epoch_call(epoch_t epoch, epoch_context_t ctx, void (*callback) (epoch_context_t));
+void	epoch_call_drain(epoch_t epoch);
 int	in_epoch(epoch_t epoch);
 int in_epoch_verbose(epoch_t epoch, int dump_onfail);
 DPCPU_DECLARE(int, epoch_cb_count);