Index: sys/vm/uma_core.c
===================================================================
--- sys/vm/uma_core.c
+++ sys/vm/uma_core.c
@@ -64,6 +64,7 @@
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/bitset.h>
+#include <sys/eventhandler.h>
 #include <sys/kernel.h>
 #include <sys/types.h>
 #include <sys/queue.h>
@@ -3199,6 +3200,9 @@
 		    "umarcl", 0);
 		if (uma_reclaim_needed) {
 			uma_reclaim_needed = 0;
+			sx_xunlock(&uma_drain_lock);
+			EVENTHANDLER_INVOKE(vm_lowmem, VM_LOW_KVA);
+			sx_xlock(&uma_drain_lock);
 			uma_reclaim_locked(true);
 		}
 	}
Index: sys/vm/vm_kern.c
===================================================================
--- sys/vm/vm_kern.c
+++ sys/vm/vm_kern.c
@@ -552,11 +552,13 @@
 	error = sysctl_handle_int(oidp, &i, 0, req);
 	if (error)
 		return (error);
-	if (i)	 
-		EVENTHANDLER_INVOKE(vm_lowmem, 0);
+	if ((i & ~(VM_LOW_KVA | VM_LOW_PAGES)) != 0)
+		return (EINVAL);
+	if (i)
+		EVENTHANDLER_INVOKE(vm_lowmem, i);
 	return (0);
 }
 
 SYSCTL_PROC(_debug, OID_AUTO, vm_lowmem, CTLTYPE_INT | CTLFLAG_RW, 0, 0,
-    debug_vm_lowmem, "I", "set to trigger vm_lowmem event");
+    debug_vm_lowmem, "I", "set to trigger vm_lowmem event with given flags");
 #endif
Index: sys/vm/vm_pageout.h
===================================================================
--- sys/vm/vm_pageout.h
+++ sys/vm/vm_pageout.h
@@ -87,6 +87,12 @@
 #define	VM_OOM_SWAPZ	2
 
 /*
+ * vm_lowmem flags.
+ */
+#define	VM_LOW_KVA	1
+#define	VM_LOW_PAGES	2
+
+/*
  *	Exported routines.
  */
 
Index: sys/vm/vm_pageout.c
===================================================================
--- sys/vm/vm_pageout.c
+++ sys/vm/vm_pageout.c
@@ -1332,7 +1332,7 @@
 		 * Decrease registered cache sizes.
 		 */
 		SDT_PROBE0(vm, , , vm__lowmem_scan);
-		EVENTHANDLER_INVOKE(vm_lowmem, 0);
+		EVENTHANDLER_INVOKE(vm_lowmem, VM_LOW_PAGES);
 		/*
 		 * We do this explicitly after the caches have been
 		 * drained above.