diff --git a/sys/vm/vm_phys.c b/sys/vm/vm_phys.c
--- a/sys/vm/vm_phys.c
+++ b/sys/vm/vm_phys.c
@@ -72,6 +72,8 @@
 
 _Static_assert(sizeof(long) * NBBY >= VM_PHYSSEG_MAX,
     "Too many physsegs.");
+_Static_assert(sizeof(long long) >= sizeof(vm_paddr_t),
+    "vm_paddr_t too big for ffsll, flsll.");
 
 #ifdef NUMA
 struct mem_affinity __read_mostly *mem_affinity;
@@ -690,18 +692,16 @@
  *
  * The physical page m's buddy must not be free.
  */
-static void
+static vm_page_t
 vm_phys_enq_range(vm_page_t m, u_int npages, struct vm_freelist *fl, int tail)
 {
-	u_int n;
 	int order;
 
-	KASSERT(npages > 0, ("vm_phys_enq_range: npages is 0"));
 	KASSERT(((VM_PAGE_TO_PHYS(m) + npages * PAGE_SIZE) &
-	    ((PAGE_SIZE << (fls(npages) - 1)) - 1)) == 0,
+	    ((PAGE_SIZE << fls(npages / 2)) - 1)) == 0,
 	    ("vm_phys_enq_range: page %p and npages %u are misaligned",
 	    m, npages));
-	do {
+	while (npages > 0) {
 		KASSERT(m->order == VM_NFREEORDER,
 		    ("vm_phys_enq_range: page %p has unexpected order %d",
 		    m, m->order));
@@ -709,10 +709,10 @@
 		KASSERT(order < VM_NFREEORDER,
 		    ("vm_phys_enq_range: order %d is out of range", order));
 		vm_freelist_add(fl, m, order, tail);
-		n = 1 << order;
-		m += n;
-		npages -= n;
-	} while (npages > 0);
+		m += 1 << order;
+		npages -= 1 << order;
+	}
+	return (m);
 }
 
 /*
@@ -744,7 +744,7 @@
 {
 	struct vm_freelist *alt, *fl;
 	vm_page_t m;
-	int avail, end, flind, freelist, i, need, oind, pind;
+	int avail, end, flind, freelist, i, oind, pind;
 
 	KASSERT(domain >= 0 && domain < vm_ndomains,
 	    ("vm_phys_alloc_npages: domain %d is out of range", domain));
@@ -762,20 +762,18 @@
 		for (oind = 0; oind < VM_NFREEORDER; oind++) {
 			while ((m = TAILQ_FIRST(&fl[oind].pl)) != NULL) {
 				vm_freelist_rem(fl, m, oind);
-				avail = 1 << oind;
-				need = imin(npages - i, avail);
-				for (end = i + need; i < end;)
+				avail = i + (1 << oind);
+				end = imin(npages, avail);
+				while (i < end)
 					ma[i++] = m++;
-				if (need < avail) {
+				if (i == npages) {
 					/*
-					 * Return excess pages to fl.  Its
-					 * order [0, oind) queues are empty.
+					 * Return excess pages to fl.  Its order
+					 * [0, oind) queues are empty.
 					 */
-					vm_phys_enq_range(m, avail - need, fl,
-					    1);
-					return (npages);
-				} else if (i == npages)
+					vm_phys_enq_range(m, avail - i, fl, 1);
 					return (npages);
+				}
 			}
 		}
 		for (oind = VM_NFREEORDER - 1; oind >= 0; oind--) {
@@ -785,21 +783,20 @@
 				    NULL) {
 					vm_freelist_rem(alt, m, oind);
 					vm_phys_set_pool(pool, m, oind);
-					avail = 1 << oind;
-					need = imin(npages - i, avail);
-					for (end = i + need; i < end;)
+					avail = i + (1 << oind);
+					end = imin(npages, avail);
+					while (i < end)
 						ma[i++] = m++;
-					if (need < avail) {
+					if (i == npages) {
 						/*
 						 * Return excess pages to fl.
 						 * Its order [0, oind) queues
 						 * are empty.
 						 */
-						vm_phys_enq_range(m, avail -
-						    need, fl, 1);
-						return (npages);
-					} else if (i == npages)
+						vm_phys_enq_range(m, avail - i,
+						    fl, 1);
 						return (npages);
+					}
 				}
 			}
 		}
@@ -1146,7 +1143,7 @@
 	 * because the size of a physical address exceeds the size of
 	 * a long.
 	 */
-	return (min(ffsl(VM_PAGE_TO_PHYS(m) >> PAGE_SHIFT) - 1,
+	return (min(ffsll(VM_PAGE_TO_PHYS(m) >> PAGE_SHIFT) - 1,
 	    VM_NFREEORDER - 1));
 }
 
@@ -1162,6 +1159,7 @@
 	struct vm_freelist *fl;
 	struct vm_phys_seg *seg;
 	vm_page_t m_end;
+	vm_paddr_t diff, lo;
 	int order;
 
 	/*
@@ -1173,15 +1171,15 @@
 	fl = (*seg->free_queues)[m->pool];
 	m_end = m + npages;
 	/* Free blocks of increasing size. */
-	while ((order = max_order(m)) < VM_NFREEORDER - 1 &&
-	    m + (1 << order) <= m_end) {
-		KASSERT(seg == &vm_phys_segs[m->segind],
-		    ("%s: page range [%p,%p) spans multiple segments",
-		    __func__, m_end - npages, m));
-		vm_freelist_add(fl, m, order, 1);
-		m += 1 << order;
+	lo = VM_PAGE_TO_PHYS(m) >> PAGE_SHIFT;
+	if (m < m_end &&
+	    (diff = lo ^ (lo + npages - 1)) != 0) {
+		order = min(flsll(diff) - 1, VM_NFREEORDER - 1);
+		m = vm_phys_enq_range(m, roundup2(lo, 1 << order) - lo, fl, 1);
 	}
+
 	/* Free blocks of maximum size. */
+	order = VM_NFREEORDER - 1;
 	while (m + (1 << order) <= m_end) {
 		KASSERT(seg == &vm_phys_segs[m->segind],
 		    ("%s: page range [%p,%p) spans multiple segments",
@@ -1560,10 +1558,8 @@
 			vm_phys_set_pool(VM_FREEPOOL_DEFAULT, m, oind);
 	}
 	/* Return excess pages to the free lists. */
-	if (&m_run[npages] < m) {
-		fl = (*queues)[VM_FREEPOOL_DEFAULT];
-		vm_phys_enq_range(&m_run[npages], m - &m_run[npages], fl, 0);
-	}
+	fl = (*queues)[VM_FREEPOOL_DEFAULT];
+	vm_phys_enq_range(&m_run[npages], m - &m_run[npages], fl, 0);
 	return (m_run);
 }