Reduce initial boot-up memory use. This is an other attempt at what

src/spaces.cc

Index: src/spaces.cc
===================================================================
--- src/spaces.cc	(revision 11201)
+++ src/spaces.cc	(working copy)
@@ -565,11 +565,10 @@
 }
 
 
-Page* MemoryAllocator::AllocatePage(PagedSpace* owner,
+Page* MemoryAllocator::AllocatePage(intptr_t size,
+                                    PagedSpace* owner,
                                     Executability executable) {
-  MemoryChunk* chunk = AllocateChunk(owner->AreaSize(),
-                                     executable,
-                                     owner);
+  MemoryChunk* chunk = AllocateChunk(size, executable, owner);
 
   if (chunk == NULL) return NULL;
 
@@ -833,7 +832,6 @@
 
 bool PagedSpace::CanExpand() {
   ASSERT(max_capacity_ % AreaSize() == 0);
-  ASSERT(Capacity() % AreaSize() == 0);
 
   if (Capacity() == max_capacity_) return false;
 
@@ -848,8 +846,14 @@
 bool PagedSpace::Expand() {
   if (!CanExpand()) return false;
 
-  Page* p = heap()->isolate()->memory_allocator()->
-      AllocatePage(this, executable());
+  intptr_t size = AreaSize();
+
+  if (anchor_.next_page() == &anchor_) {
+    size = SizeOfFirstPage();
+  }
+
+  Page* p = heap()->isolate()->memory_allocator()->AllocatePage(
+      size, this, executable());
   if (p == NULL) return false;
 
   ASSERT(Capacity() <= max_capacity_);
@@ -860,6 +864,39 @@
 }
 
 
+intptr_t PagedSpace::SizeOfFirstPage() {
+  int size = 0;
+  void* dummy;
+  switch (identity()) {
+    case OLD_POINTER_SPACE:
+      size = 64 * sizeof(dummy) * KB;

[Michael Starzinger, 2012/04/02 08:25:05]

Why not use kPointerSize here?

+      break;
+    case OLD_DATA_SPACE:
+      size = 192 * KB;
+      break;
+    case MAP_SPACE:
+      size = 128 * KB;
+      break;
+    case CELL_SPACE:
+      size = 96 * KB;
+      break;
+    case CODE_SPACE:
+      if (sizeof(dummy) == 8) {

[Michael Starzinger, 2012/04/02 08:25:05]

Why not use kPointerSize here?

+        // On x64 we allocate code pages in a special way (from the reserved
+        // 2Byte area). That part of the code is not yet upgraded to handle
+        // small pages.
+        size = AreaSize();
+      } else {
+        size = 384 * KB;
+      }
+      break;
+    default:
+      UNREACHABLE();
+  }
+  return Min(size, AreaSize());
+}
+
+
 int PagedSpace::CountTotalPages() {
   PageIterator it(this);
   int count = 0;
@@ -903,7 +940,6 @@
   }
 
   ASSERT(Capacity() > 0);
-  ASSERT(Capacity() % AreaSize() == 0);
   accounting_stats_.ShrinkSpace(AreaSize());
 }
 
@@ -1042,6 +1078,7 @@
   if (!to_space_.Commit()) {
     return false;
   }
+  ASSERT(!from_space_.is_committed());  // No need to use memory yet.
 
   start_ = chunk_base_;
   address_mask_ = ~(2 * reserved_semispace_capacity - 1);