diff --git a/sys/vm/vm_reserv.h b/sys/vm/vm_reserv.h
--- a/sys/vm/vm_reserv.h
+++ b/sys/vm/vm_reserv.h
@@ -55,6 +55,7 @@
 boolean_t	vm_reserv_free_page(vm_page_t m);
 void		vm_reserv_init(void);
 bool		vm_reserv_is_page_free(vm_page_t m);
+bool		vm_reserv_is_populated(vm_page_t m, int npages);
 int		vm_reserv_level(vm_page_t m);
 int		vm_reserv_level_iffullpop(vm_page_t m);
 vm_page_t	vm_reserv_reclaim_contig(int domain, u_long npages,
diff --git a/sys/vm/vm_reserv.c b/sys/vm/vm_reserv.c
--- a/sys/vm/vm_reserv.c
+++ b/sys/vm/vm_reserv.c
@@ -1058,6 +1058,27 @@
 	return (!bit_test(rv->popmap, m - rv->pages));
 }
 
+/*
+ * Returns true if the given page is part of a block of npages, starting at a
+ * multiple of npages, that are all allocated.  Otherwise, returns false.
+ */
+bool
+vm_reserv_is_populated(vm_page_t m, int npages)
+{
+	vm_reserv_t rv;
+	int index;
+
+	KASSERT(npages <= VM_LEVEL_0_NPAGES,
+	    ("%s: npages %d exceeds VM_LEVEL_0_NPAGES", __func__, npages));
+	KASSERT(powerof2(npages),
+	    ("%s: npages %d is not a power of 2", __func__, npages));
+	rv = vm_reserv_from_page(m);
+	if (rv->object == NULL)
+		return (false);
+	index = rounddown2(m - rv->pages, npages);
+	return (bit_ntest(rv->popmap, index, index + npages - 1, 1));
+}
+
 /*
  * If the given page belongs to a reservation, returns the level of that
  * reservation.  Otherwise, returns -1.