Simplify the inner loop of pmap_collect(): While iterating over the page's

pv list, there is no point in checking whether or not the pv list is empty.
Instead, wait until the loop completes.

2 files changed, 5 insertions, 8 deletions

diff --git a/sys/i386/i386/pmap.c b/sys/i386/i386/pmap.c
index f2fce2d..9dbab4e 100644
--- a/sys/i386/i386/pmap.c
+++ b/sys/i386/i386/pmap.c
@@ -2147,7 +2147,6 @@ SYSCTL_INT(_vm_pmap, OID_AUTO, pmap_collect_active, CTLFLAG_RD, &pmap_collect_ac
 static void
 pmap_collect(pmap_t locked_pmap, struct vpgqueues *vpq)
 {
-	struct md_page *pvh;
 	pd_entry_t *pde;
 	pmap_t pmap;
 	pt_entry_t *pte, tpte;
@@ -2184,15 +2183,13 @@ pmap_collect(pmap_t locked_pmap, struct vpgqueues *vpq)
 			pmap_invalidate_page(pmap, va);
 			pmap_free_zero_pages(free);
 			TAILQ_REMOVE(&m->md.pv_list, pv, pv_list);
-			if (TAILQ_EMPTY(&m->md.pv_list)) {
-				pvh = pa_to_pvh(VM_PAGE_TO_PHYS(m));
-				if (TAILQ_EMPTY(&pvh->pv_list))
-					vm_page_flag_clear(m, PG_WRITEABLE);
-			}
 			free_pv_entry(pmap, pv);
 			if (pmap != locked_pmap)
 				PMAP_UNLOCK(pmap);
 		}
+		if (TAILQ_EMPTY(&m->md.pv_list) &&
+		    TAILQ_EMPTY(&pa_to_pvh(VM_PAGE_TO_PHYS(m))->pv_list))
+			vm_page_flag_clear(m, PG_WRITEABLE);
 	}
 	sched_unpin();
 }
diff --git a/sys/i386/xen/pmap.c b/sys/i386/xen/pmap.c
index ed3b0b0..67bbd27 100644
--- a/sys/i386/xen/pmap.c
+++ b/sys/i386/xen/pmap.c
@@ -2078,12 +2078,12 @@ pmap_collect(pmap_t locked_pmap, struct vpgqueues *vpq)
 			pmap_invalidate_page(pmap, va);
 			pmap_free_zero_pages(free);
 			TAILQ_REMOVE(&m->md.pv_list, pv, pv_list);
-			if (TAILQ_EMPTY(&m->md.pv_list))
-				vm_page_flag_clear(m, PG_WRITEABLE);
 			free_pv_entry(pmap, pv);
 			if (pmap != locked_pmap)
 				PMAP_UNLOCK(pmap);
 		}
+		if (TAILQ_EMPTY(&m->md.pv_list))
+			vm_page_flag_clear(m, PG_WRITEABLE);
 	}
 	sched_unpin();
 }