Multi-page newspace.

src/spaces.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1031 matching lines @@
 // that it works (it depends on the invariants we are checking).
 void NewSpace::Verify() {
   // The allocation pointer should be in the space or at the very end.
   ASSERT_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_);
 
   // There should be objects packed in from the low address up to the
   // allocation pointer.
   NewSpacePage* page = to_space_.first_page();
   Address current = page->body();
   CHECK_EQ(current, to_space_.space_low());
-  CHECK(end_page->ContainsLimit(top()));
 
   while (current != top()) {
     if (current == page->body_limit()) {
       // At end of page, switch to next page.
       page = page->next_page();
       // Next page should be valid.
       CHECK(!page->is_anchor());
       current = page->body();
     }
     // The allocation pointer should not be in the middle of an object.
@@ skipping 26 matching lines @@
   ASSERT_EQ(from_space_.id(), kFromSpace);
   ASSERT_EQ(to_space_.id(), kToSpace);
   from_space_.Verify();
   to_space_.Verify();
 }
 #endif
 
 
 bool SemiSpace::Commit() {
   ASSERT(!is_committed());
-  // TODO(gc): Rewrite completely when switching to n-page new-space.
-  // Create one page.
-  int pagesize = Page::kPageSize;
-  if (!heap()->isolate()->memory_allocator()->CommitBlock(
-      start_, pagesize, executable())) {
+  int pages = capacity_ / Page::kPageSize;
+  if (!heap()->isolate()->memory_allocator()->CommitBlock(start_,
+                                                          capacity_,
+                                                          executable())) {
     return false;
   }
-  NewSpacePage* page = NewSpacePage::Initialize(heap(), start_, this);
-  page->InsertAfter(&anchor_);
 
-  // Maybe create a second.
-  if (capacity_ >= 2 * pagesize) {
-    Address last_page_address =
-      start_ + ((capacity_ - pagesize) & ~Page::kPageAlignmentMask);
-    if (heap()->isolate()->memory_allocator()->CommitBlock(
-        last_page_address, pagesize, executable())) {
-      NewSpacePage* last_page = NewSpacePage::Initialize(heap(),
-                                                         last_page_address,
-                                                         this);
-      last_page->InsertAfter(page);
-    } else {
-      UNREACHABLE();  // TODO(gc): Don't rely on this. Splitting the commit
-                      // is only temporary.
-    }
+  NewSpacePage* page = anchor();
+  for (int i = 0; i < pages; i++) {
+    NewSpacePage* new_page =
+      NewSpacePage::Initialize(heap(), start_ + i * Page::kPageSize, this);
+    new_page->InsertAfter(page);
+    page = new_page;
   }
 
   committed_ = true;
   Reset();
   return true;
 }
 
 
 bool SemiSpace::Uncommit() {
   ASSERT(is_committed());
-  // TODO(gc): Rewrite completely when switching to n-page new-space.
-  NewSpacePage* last_page = anchor()->prev_page();
-  while (last_page != anchor()) {
-    NewSpacePage* temp_page = last_page->prev_page();
-    last_page->Unlink();
-    if (!heap()->isolate()->memory_allocator()->UncommitBlock(
-      last_page->address(), Page::kPageSize)) {
-      return false;
-    }
-    last_page = temp_page;
+  if (!heap()->isolate()->memory_allocator()->UncommitBlock(start_,
+                                                            capacity_)) {
+    return false;
   }
+  anchor()->set_next_page(anchor());
+  anchor()->set_prev_page(anchor());
 
   committed_ = false;
   return true;
 }
 
 
 void SemiSpace::Reset() {
   ASSERT(anchor_.next_page() != &anchor_);
   current_page_ = anchor_.next_page();
 }
@@ skipping 1290 matching lines @@
   for (HeapObject* obj = obj_it.Next(); obj != NULL; obj = obj_it.Next()) {
     if (obj->IsCode()) {
       Code* code = Code::cast(obj);
       isolate->code_kind_statistics()[code->kind()] += code->Size();
     }
   }
 }
 #endif  // DEBUG
 
 } }  // namespace v8::internal