Use emergency memory in the case of out of memory during evacuation.

src/spaces.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/base/platform/platform.h"
 #include "src/full-codegen.h"
 #include "src/macro-assembler.h"
 #include "src/mark-compact.h"
@@ skipping 911 matching lines @@
   if (!chunk->InNewSpace() && !static_cast<Page*>(chunk)->WasSwept()) {
     static_cast<PagedSpace*>(chunk->owner())->IncrementUnsweptFreeBytes(-by);
   }
   chunk->IncrementLiveBytes(by);
 }
 
 
 // -----------------------------------------------------------------------------
 // PagedSpace implementation
 
-PagedSpace::PagedSpace(Heap* heap,
-                       intptr_t max_capacity,
-                       AllocationSpace id,
+PagedSpace::PagedSpace(Heap* heap, intptr_t max_capacity, AllocationSpace id,
                        Executability executable)
     : Space(heap, id, executable),
       free_list_(this),
       swept_precisely_(true),
       unswept_free_bytes_(0),
-      end_of_unswept_pages_(NULL) {
+      end_of_unswept_pages_(NULL),
+      emergency_memory_(NULL) {
   if (id == CODE_SPACE) {
     area_size_ = heap->isolate()->memory_allocator()->
         CodePageAreaSize();
   } else {
     area_size_ = Page::kPageSize - Page::kObjectStartOffset;
   }
   max_capacity_ = (RoundDown(max_capacity, Page::kPageSize) / Page::kPageSize)
       * AreaSize();
   accounting_stats_.Clear();
 
@@ skipping 192 matching lines @@
     heap()->isolate()->memory_allocator()->Free(page);
   } else {
     heap()->QueueMemoryChunkForFree(page);
   }
 
   ASSERT(Capacity() > 0);
   accounting_stats_.ShrinkSpace(AreaSize());
 }
 
 
+void PagedSpace::CreateEmergencyMemory() {
+  emergency_memory_ = heap()->isolate()->memory_allocator()->AllocateChunk(
+      AreaSize(), AreaSize(), executable(), this);
+}
+
+
+void PagedSpace::FreeEmergencyMemory() {
+  Page* page = static_cast<Page*>(emergency_memory_);
+  ASSERT(page->LiveBytes() == 0);
+  ASSERT(AreaSize() == page->area_size());
+  ASSERT(!free_list_.ContainsPageFreeListItems(page));
+  heap()->isolate()->memory_allocator()->Free(page);
+  emergency_memory_ = NULL;
+}
+
+
+void PagedSpace::UseEmergencyMemory() {
+  Page* page = Page::Initialize(heap(), emergency_memory_, executable(), this);
+  page->InsertAfter(anchor_.prev_page());
+  emergency_memory_ = NULL;
+}
+
+
 #ifdef DEBUG
 void PagedSpace::Print() { }
 #endif
 
 #ifdef VERIFY_HEAP
 void PagedSpace::Verify(ObjectVisitor* visitor) {
   // We can only iterate over the pages if they were swept precisely.
   if (!swept_precisely_) return;
 
   bool allocation_pointer_found_in_space =
@@ skipping 1989 matching lines @@
     object->ShortPrint();
     PrintF("\n");
   }
   printf(" --------------------------------------\n");
   printf(" Marked: %x, LiveCount: %x\n", mark_size, LiveBytes());
 }
 
 #endif  // DEBUG
 
 } }  // namespace v8::internal