[heap] Add more tasks for parallel compaction

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/atomic-utils.h"
 #include "src/base/atomicops.h"
@@ skipping 1613 matching lines @@
 //     and limit when the object we need to allocate is 256-2047 words in size.
 //     These spaces are call large.
 // At least 16384 words.  This list is for objects of 2048 words or larger.
 //     Empty pages are added to this list.  These spaces are called huge.
 class FreeList {
  public:
   explicit FreeList(PagedSpace* owner);
 
   intptr_t Concatenate(FreeList* free_list);
 
+  // Divide {this} free lists up among {other_free_lists} up to some certain
+  // {limit} of bytes. Note that this operation needs to iterate over nodes
+  // one-by-one, making it a potentially slow operation.
+  void Divide(FreeList** other_free_lists, int num, intptr_t limit);
+
   // Clear the free list.
   void Reset();
 
   // Return the number of bytes available on the free list.
   intptr_t available() {
     return small_list_.available() + medium_list_.available() +
            large_list_.available() + huge_list_.available();
   }
 
   // Place a node on the free list.  The block of size 'size_in_bytes'
@@ skipping 346 matching lines @@
   inline int AreaSize() { return area_size_; }
 
   // Merges {other} into the current space. Note that this modifies {other},
   // e.g., removes its bump pointer area and resets statistics.
   void MergeCompactionSpace(CompactionSpace* other);
 
   void MoveOverFreeMemory(PagedSpace* other);
 
   virtual bool is_local() { return false; }
 
+  // Adds external memory starting at {start} of {size_in_bytes} to the space.
+  void AddExternalMemory(Address start, int size_in_bytes) {

[Hannes Payer (out of office), 2015/09/23 08:47:22]

Call it AddMemory, to get the naming in sync with RemoveMemory.

+    IncreaseCapacity(size_in_bytes);
+    Free(start, size_in_bytes);
+  }
+
+  void RemoveMemory(int size) { accounting_stats_.DecreaseCapacity(size); }

[Hannes Payer (out of office), 2015/09/23 08:47:22]

To make this one dual with AddMemory, it should actually also remove memory from
the free list. WDYT?

[Michael Lippautz, 2015/09/23 11:49:01]

Done.

+
  protected:
   // PagedSpaces that should be included in snapshots have different, i.e.,
   // smaller, initial pages.
   virtual bool snapshotable() { return true; }
 
   FreeList* free_list() { return &free_list_; }
 
   bool HasPages() { return anchor_.next_page() != &anchor_; }
 
   // Cleans up the space, frees all pages in this space except those belonging
@@ skipping 727 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);
-  }
-
   virtual bool is_local() { return true; }
 
  protected:
   // The space is temporary and not included in any snapshots.
   virtual bool snapshotable() { return false; }
 };
 
 
 // A collection of |CompactionSpace|s used by a single compaction task.
 class CompactionSpaceCollection : public Malloced {
@@ skipping 214 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_