Index: sys/vm/vm_phys.c
===================================================================
--- sys/vm/vm_phys.c
+++ sys/vm/vm_phys.c
@@ -1293,7 +1293,7 @@
 {
 	struct vm_freelist *fl;
 	struct vm_phys_seg *seg;
-	vm_paddr_t pa, pa_half;
+	vm_paddr_t pa, pa_half, pa_low;
 	vm_page_t m_set, m_tmp;
 	int order;
 
@@ -1304,15 +1304,18 @@
 	 */
 	seg = &vm_phys_segs[m->segind];
 	vm_domain_free_assert_locked(VM_DOMAIN(seg->domain));
-	for (m_set = m, order = 0; m_set->order == VM_NFREEORDER &&
-	    order < VM_NFREEORDER - 1; ) {
-		order++;
-		pa = m->phys_addr & (~(vm_paddr_t)0 << (PAGE_SHIFT + order));
-		if (pa >= seg->start)
-			m_set = &seg->first_page[atop(pa - seg->start)];
-		else
-			return (false);
+	pa = VM_PAGE_TO_PHYS(m);
+	pa_low = pa &- ptoa(1 << VM_NFREEORDER);
+	if (pa_low < seg->start)
+		pa_low = seg->start;
+	order = 0;
+	for (m_set = m; pa > pa_low && m_set->order == VM_NFREEORDER;
+	    m_set = &seg->first_page[atop(pa - seg->start)]) {
+		order = ffsll(atop(pa));
+		pa &= pa - 1;
 	}
+	if (pa < seg->start)
+		return (false);
 	if (m_set->order < order)
 		return (false);
 	if (m_set->order == VM_NFREEORDER)
@@ -1332,8 +1335,8 @@
 	vm_freelist_rem(fl, m_set, order);
 	while (order > 0) {
 		order--;
-		pa_half = m_set->phys_addr ^ (1 << (PAGE_SHIFT + order));
-		if (m->phys_addr < pa_half)
+		pa_half = VM_PAGE_TO_PHYS(m_set) ^ ptoa(1 << order);
+		if (VM_PAGE_TO_PHYS(m) < pa_half)
 			m_tmp = &seg->first_page[atop(pa_half - seg->start)];
 		else {
 			m_tmp = m_set;