[heap] Sort sweep pages list by free 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/atomic-utils.h"
 #include "src/base/atomicops.h"
@@ skipping 2098 matching lines @@
     return !p->IsEvacuationCandidate() &&
            !p->IsFlagSet(Page::RESCAN_ON_EVACUATION) && !p->WasSwept();
   }
 
   // This function tries to steal size_in_bytes memory from the sweeper threads
   // free-lists. If it does not succeed stealing enough memory, it will wait
   // for the sweeper threads to finish sweeping.
   // It returns true when sweeping is completed and false otherwise.
   bool EnsureSweeperProgress(intptr_t size_in_bytes);
 
-  void set_end_of_unswept_pages(Page* page) { end_of_unswept_pages_ = page; }
-
-  Page* end_of_unswept_pages() { return end_of_unswept_pages_; }
-
   Page* FirstPage() { return anchor_.next_page(); }
   Page* LastPage() { return anchor_.prev_page(); }
 
   void EvictEvacuationCandidatesFromLinearAllocationArea();
 
   bool CanExpand(size_t size);
 
   // Returns the number of total pages in this space.
   int CountTotalPages();
 
   // Return size of allocatable area on a page in this space.
   inline int AreaSize() { return area_size_; }
 
   virtual bool is_local() { return false; }
 
   // 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 DivideUponCompactionSpaces(CompactionSpaceCollection** other, int num,
                                   intptr_t limit = kCompactionMemoryWanted);
 
   // Refills the free list from the corresponding free list filled by the
   // sweeper.
   virtual void RefillFreeList();
 
  protected:
+  static const int kMaxPagesSweptDuringSlowAllocation = 1;

[Hannes Payer (out of office), 2016/01/21 10:35:22]

This one can be local in the function.

+
   void AddMemory(Address start, intptr_t size);
 
   FreeSpace* TryRemoveMemory(intptr_t size_in_bytes);
 
   void MoveOverFreeMemory(PagedSpace* other);
 
   // PagedSpaces that should be included in snapshots have different, i.e.,
   // smaller, initial pages.
   virtual bool snapshotable() { return true; }
 
@@ skipping 36 matching lines @@
 
   // The dummy page that anchors the double linked list of pages.
   Page anchor_;
 
   // The space's free list.
   FreeList free_list_;
 
   // Normal allocation information.
   AllocationInfo allocation_info_;
 
-  // The sweeper threads iterate over the list of pointer and data space pages
-  // and sweep these pages concurrently. They will stop sweeping after the
-  // end_of_unswept_pages_ page.
-  Page* end_of_unswept_pages_;
-
   // Mutex guarding any concurrent access to the space.
   base::Mutex space_mutex_;
 
   friend class MarkCompactCollector;
   friend class PageIterator;
 
   // Used in cctest.
   friend class HeapTester;
 };
 
@@ skipping 999 matching lines @@
     count = 0;
   }
   // Must be small, since an iteration is used for lookup.
   static const int kMaxComments = 64;
 };
 #endif
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_SPACES_H_