Index: sys/amd64/amd64/pmap.c
===================================================================
--- sys/amd64/amd64/pmap.c
+++ sys/amd64/amd64/pmap.c
@@ -2209,12 +2209,16 @@
 pmap_free_zero_pages(struct spglist *free)
 {
 	vm_page_t m;
+	int count;
 
+	count = 0;
 	while ((m = SLIST_FIRST(free)) != NULL) {
 		SLIST_REMOVE_HEAD(free, plinks.s.ss);
 		/* Preserve the page's PG_ZERO setting. */
 		vm_page_free_toq(m);
+		count++;
 	}
+	atomic_subtract_int(&vm_cnt.v_wire_count, count);
 }
 
 /*
@@ -2321,11 +2325,10 @@
 	}
 
 	/*
-	 * This is a release store so that the ordinary store unmapping
-	 * the page table page is globally performed before TLB shoot-
-	 * down is begun.
+	 * Ensure that the ordinary store unmapping the page table page is
+	 * globally visible before TLB shootdown is begun.
 	 */
-	atomic_subtract_rel_int(&vm_cnt.v_wire_count, 1);
+	atomic_thread_fence_rel();
 
 	/* 
 	 * Put page on a list so that it is released after
@@ -3010,7 +3013,6 @@
 		SLIST_REMOVE_HEAD(&free, plinks.s.ss);
 		/* Recycle a freed page table page. */
 		m_pc->wire_count = 1;
-		atomic_add_int(&vm_cnt.v_wire_count, 1);
 	}
 	pmap_free_zero_pages(&free);
 	return (m_pc);
@@ -3678,7 +3680,6 @@
 			    ("pmap_remove_pde: pte page wire count error"));
 			mpte->wire_count = 0;
 			pmap_add_delayed_free_list(mpte, free, FALSE);
-			atomic_subtract_int(&vm_cnt.v_wire_count, 1);
 		}
 	}
 	return (pmap_unuse_pt(pmap, sva, *pmap_pdpe(pmap, sva), free));
@@ -5622,7 +5623,6 @@
 						    ("pmap_remove_pages: pte page wire count error"));
 						mpte->wire_count = 0;
 						pmap_add_delayed_free_list(mpte, &free, FALSE);
-						atomic_subtract_int(&vm_cnt.v_wire_count, 1);
 					}
 				} else {
 					pmap_resident_count_dec(pmap, 1);
Index: sys/i386/i386/pmap.c
===================================================================
--- sys/i386/i386/pmap.c
+++ sys/i386/i386/pmap.c
@@ -1792,11 +1792,10 @@
 	--pmap->pm_stats.resident_count;
 
 	/*
-	 * This is a release store so that the ordinary store unmapping
-	 * the page table page is globally performed before TLB shoot-
-	 * down is begun.
+	 * Ensure that the ordinary store unmapping the page table page is
+	 * globally visible before TLB shootdown is begun.
 	 */
-	atomic_subtract_rel_int(&vm_cnt.v_wire_count, 1);
+	atomic_thread_fence_rel();
 
 	/*
 	 * Do an invltlb to make the invalidated mapping
@@ -2061,11 +2060,11 @@
 		    ("pmap_release: got wrong ptd page"));
 #endif
 		m->wire_count--;
-		atomic_subtract_int(&vm_cnt.v_wire_count, 1);
 		vm_page_free_zero(m);
 	}
+	atomic_subtract_int(&vm_cnt.v_wire_count, NPGPTD);
 }
-
+
 static int
 kvm_size(SYSCTL_HANDLER_ARGS)
 {
@@ -2324,7 +2323,6 @@
 		SLIST_REMOVE_HEAD(&free, plinks.s.ss);
 		/* Recycle a freed page table page. */
 		m_pc->wire_count = 1;
-		atomic_add_int(&vm_cnt.v_wire_count, 1);
 	}
 	pmap_free_zero_pages(&free);
 	return (m_pc);
@@ -2873,7 +2871,6 @@
 			    ("pmap_remove_pde: pte page wire count error"));
 			mpte->wire_count = 0;
 			pmap_add_delayed_free_list(mpte, free, FALSE);
-			atomic_subtract_int(&vm_cnt.v_wire_count, 1);
 		}
 	}
 }
@@ -4593,7 +4590,6 @@
 						    ("pmap_remove_pages: pte page wire count error"));
 						mpte->wire_count = 0;
 						pmap_add_delayed_free_list(mpte, &free, FALSE);
-						atomic_subtract_int(&vm_cnt.v_wire_count, 1);
 					}
 				} else {
 					pmap->pm_stats.resident_count--;