Revert of [heap] Add page evacuation mode for new->new

src/heap/spaces.cc

Index: src/heap/spaces.cc
diff --git a/src/heap/spaces.cc b/src/heap/spaces.cc
index 4fe3886e46bb0e62e6e9f4c9d37cfe3458f0acda..a0eae92d69f994b9d78be8d544b86beb6bd8eacd 100644
--- a/src/heap/spaces.cc
+++ b/src/heap/spaces.cc
@@ -1386,6 +1386,7 @@
   from_space_.TearDown();
 }
 
+
 void NewSpace::Flip() { SemiSpace::Swap(&from_space_, &to_space_); }
 
 
@@ -1431,48 +1432,6 @@
   DCHECK_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_);
 }
 
-bool NewSpace::Rebalance() {
-  CHECK(heap()->promotion_queue()->is_empty());
-  // Order here is important to make use of the page pool.
-  return to_space_.EnsureCurrentCapacity() &&
-         from_space_.EnsureCurrentCapacity();
-}
-
-bool SemiSpace::EnsureCurrentCapacity() {
-  if (is_committed()) {
-    const int expected_pages = current_capacity_ / Page::kPageSize;
-    int actual_pages = 0;
-    Page* current_page = anchor()->next_page();
-    while (current_page != anchor()) {
-      actual_pages++;
-      current_page = current_page->next_page();
-      if (actual_pages > expected_pages) {
-        Page* to_remove = current_page->prev_page();
-        // Make sure we don't overtake the actual top pointer.
-        DCHECK_NE(to_remove, current_page_);
-        to_remove->Unlink();
-        heap()->memory_allocator()->Free<MemoryAllocator::kPooledAndQueue>(
-            to_remove);
-      }
-    }
-    while (actual_pages < expected_pages) {
-      actual_pages++;
-      current_page =
-          heap()->memory_allocator()->AllocatePage<MemoryAllocator::kPooled>(
-              Page::kAllocatableMemory, this, executable());
-      if (current_page == nullptr) return false;
-      DCHECK_NOT_NULL(current_page);
-      current_page->InsertAfter(anchor());
-      Bitmap::Clear(current_page);
-      current_page->SetFlags(anchor()->prev_page()->GetFlags(),
-                             Page::kCopyAllFlags);
-      heap()->CreateFillerObjectAt(current_page->area_start(),
-                                   current_page->area_size(),
-                                   ClearRecordedSlots::kNo);
-    }
-  }
-  return true;
-}
 
 void LocalAllocationBuffer::Close() {
   if (IsValid()) {
@@ -1915,17 +1874,21 @@
   current_page_ = anchor_.next_page();
 }
 
-void SemiSpace::RemovePage(Page* page) {
-  if (current_page_ == page) {
-    current_page_ = page->prev_page();
-  }
-  page->Unlink();
-}
-
-void SemiSpace::PrependPage(Page* page) {
-  page->SetFlags(current_page()->GetFlags(), Page::kCopyAllFlags);
-  page->set_owner(this);
-  page->InsertAfter(anchor());
+bool SemiSpace::ReplaceWithEmptyPage(Page* old_page) {
+  // TODO(mlippautz): We do not have to get a new page here when the semispace
+  // is uncommitted later on.
+  Page* new_page = heap()->memory_allocator()->AllocatePage(
+      Page::kAllocatableMemory, this, executable());
+  if (new_page == nullptr) return false;
+  Bitmap::Clear(new_page);
+  new_page->SetFlags(old_page->GetFlags(), Page::kCopyAllFlags);
+  new_page->set_next_page(old_page->next_page());
+  new_page->set_prev_page(old_page->prev_page());
+  old_page->next_page()->set_prev_page(new_page);
+  old_page->prev_page()->set_next_page(new_page);
+  heap()->CreateFillerObjectAt(new_page->area_start(), new_page->area_size(),
+                               ClearRecordedSlots::kNo);
+  return true;
 }
 
 void SemiSpace::Swap(SemiSpace* from, SemiSpace* to) {