[heap] Make compaction space accept external memory.

src/heap/spaces.h

 // 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.
 
 #ifndef V8_HEAP_SPACES_H_
 #define V8_HEAP_SPACES_H_
 
 #include "src/allocation.h"
 #include "src/base/atomicops.h"
 #include "src/base/bits.h"
@@ skipping 1573 matching lines @@
   // starting at 'start' is placed on the free list.  The return value is the
   // number of bytes that have been lost due to internal fragmentation by
   // freeing the block.  Bookkeeping information will be written to the block,
   // i.e., its contents will be destroyed.  The start address should be word
   // aligned, and the size should be a non-zero multiple of the word size.
   int Free(Address start, int size_in_bytes);
 
   // This method returns how much memory can be allocated after freeing
   // maximum_freed memory.
   static inline int GuaranteedAllocatable(int maximum_freed) {
-    if (maximum_freed < kSmallListMin) {
+    if (maximum_freed <= kSmallListMin) {
       return 0;
     } else if (maximum_freed <= kSmallListMax) {
       return kSmallAllocationMax;
     } else if (maximum_freed <= kMediumListMax) {
       return kMediumAllocationMax;
     } else if (maximum_freed <= kLargeListMax) {
       return kLargeAllocationMax;
     }
     return maximum_freed;
   }
@@ skipping 19 matching lines @@
   void RepairLists(Heap* heap);
 
   intptr_t EvictFreeListItems(Page* p);
   bool ContainsPageFreeListItems(Page* p);
 
   FreeListCategory* small_list() { return &small_list_; }
   FreeListCategory* medium_list() { return &medium_list_; }
   FreeListCategory* large_list() { return &large_list_; }
   FreeListCategory* huge_list() { return &huge_list_; }
 
-  static const int kSmallListMin = 0x20 * kPointerSize;
-
  private:
   // The size range of blocks, in bytes.
   static const int kMinBlockSize = 3 * kPointerSize;
   static const int kMaxBlockSize = Page::kMaxRegularHeapObjectSize;
 
+  static const int kSmallListMin = 0x1f * kPointerSize;
+  static const int kSmallListMax = 0xff * kPointerSize;
+  static const int kMediumListMax = 0x7ff * kPointerSize;
+  static const int kLargeListMax = 0x3fff * kPointerSize;
+  static const int kSmallAllocationMax = kSmallListMin;
+  static const int kMediumAllocationMax = kSmallListMax;
+  static const int kLargeAllocationMax = kMediumListMax;
+
   FreeSpace* FindNodeFor(int size_in_bytes, int* node_size);
 
   PagedSpace* owner_;
   Heap* heap_;
-
-  static const int kSmallListMax = 0xff * kPointerSize;
-  static const int kMediumListMax = 0x7ff * kPointerSize;
-  static const int kLargeListMax = 0x3fff * kPointerSize;
-  static const int kSmallAllocationMax = kSmallListMin - kPointerSize;
-  static const int kMediumAllocationMax = kSmallListMax;
-  static const int kLargeAllocationMax = kMediumListMax;
   FreeListCategory small_list_;
   FreeListCategory medium_list_;
   FreeListCategory large_list_;
   FreeListCategory huge_list_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(FreeList);
 };
 
 
 class AllocationResult {
@@ skipping 137 matching lines @@
   // The allocation limit address.
   Address* allocation_limit_address() {
     return allocation_info_.limit_address();
   }
 
   // Allocate the requested number of bytes in the space if possible, return a
   // failure object if not.
   MUST_USE_RESULT inline AllocationResult AllocateRawUnaligned(
       int size_in_bytes);
 
+  MUST_USE_RESULT inline AllocationResult AllocateRawUnalignedSynchronized(
+      int size_in_bytes);
+
   // Allocate the requested number of bytes in the space double aligned if
   // possible, return a failure object if not.
   MUST_USE_RESULT inline AllocationResult AllocateRawAligned(
       int size_in_bytes, AllocationAlignment alignment);
 
   // Allocate the requested number of bytes in the space and consider allocation
   // alignment if needed.
   MUST_USE_RESULT inline AllocationResult AllocateRaw(
       int size_in_bytes, AllocationAlignment alignment);
 
@@ skipping 176 matching lines @@
   // and sweep these pages concurrently. They will stop sweeping after the
   // end_of_unswept_pages_ page.
   Page* end_of_unswept_pages_;
 
   // Emergency memory is the memory of a full page for a given space, allocated
   // conservatively before evacuating a page. If compaction fails due to out
   // of memory error the emergency memory can be used to complete compaction.
   // If not used, the emergency memory is released after compaction.
   MemoryChunk* emergency_memory_;
 
+  // Mutex guarding any concurrent access to the space.
+  base::Mutex space_mutex_;
+
+  friend class MarkCompactCollector;
   friend class PageIterator;
-  friend class MarkCompactCollector;
 };
 
 
 class NumberAndSizeInfo BASE_EMBEDDED {
  public:
   NumberAndSizeInfo() : number_(0), bytes_(0) {}
 
   int number() const { return number_; }
   void increment_number(int num) { number_ += num; }
 
@@ skipping 661 matching lines @@
 };
 
 // -----------------------------------------------------------------------------
 // Compaction space that is used temporarily during compaction.
 
 class CompactionSpace : public PagedSpace {
  public:
   CompactionSpace(Heap* heap, AllocationSpace id, Executability executable)
       : PagedSpace(heap, id, executable) {}
 
+  // Adds external memory starting at {start} of {size_in_bytes} to the space.
+  void AddExternalMemory(Address start, int size_in_bytes) {
+    IncreaseCapacity(size_in_bytes);
+    Free(start, size_in_bytes);
+  }
+
  protected:
   // The space is temporary and not included in any snapshots.
   virtual bool snapshotable() { return false; }
 };
 
 
 // -----------------------------------------------------------------------------
 // Old object space (includes the old space of objects and code space)
 
 class OldSpace : public PagedSpace {
@@ skipping 186 matching lines @@
     count = 0;
   }
   // Must be small, since an iteration is used for lookup.
   static const int kMaxComments = 64;
 };
 #endif
 }
 }  // namespace v8::internal
 
 #endif  // V8_HEAP_SPACES_H_