Do not delay sweeping of pages that are completely free.

R=erik.corry@gmail.com

Review URL: http://codereview.chromium.org/8997004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10273 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/mark-compact.cc

@@ -3623,14 +3623,6 @@ void MarkCompactCollector::SweepSpace(PagedSpace* space, SweeperType sweeper) {
       continue;
     }
 
-    if (lazy_sweeping_active) {
-      if (FLAG_gc_verbose) {
-        PrintF("Sweeping 0x%" V8PRIxPTR " lazily postponed.\n",
-               reinterpret_cast<intptr_t>(p));
-      }
-      continue;
-    }
-
     // One unused page is kept, all further are released before sweeping them.
     if (p->LiveBytes() == 0) {
       if (unused_page_present) {
@@ -3644,6 +3636,14 @@ void MarkCompactCollector::SweepSpace(PagedSpace* space, SweeperType sweeper) {
       unused_page_present = true;
     }
 
+    if (lazy_sweeping_active) {
+      if (FLAG_gc_verbose) {
+        PrintF("Sweeping 0x%" V8PRIxPTR " lazily postponed.\n",
+               reinterpret_cast<intptr_t>(p));
+      }
+      continue;
+    }
+
     switch (sweeper) {
       case CONSERVATIVE: {
         if (FLAG_gc_verbose) {

src/spaces.cc

@@ -752,7 +752,7 @@ int PagedSpace::CountTotalPages() {
 void PagedSpace::ReleasePage(Page* page) {
   ASSERT(page->LiveBytes() == 0);
 
-  // Adjust list of unswept pages if the page is it's head or tail.
+  // Adjust list of unswept pages if the page is the head of the list.
   if (first_unswept_page_ == page) {
     first_unswept_page_ = page->next_page();
     if (first_unswept_page_ == anchor()) {