[heap] make inline allocation step size dynamic

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 2503 matching lines @@
 class InlineAllocationObserver {
  public:
   explicit InlineAllocationObserver(intptr_t step_size)
       : step_size_(step_size), bytes_to_next_step_(step_size) {
     DCHECK(step_size >= kPointerSize && (step_size & kHeapObjectTagMask) == 0);
   }
   virtual ~InlineAllocationObserver() {}
 
  private:
   intptr_t step_size() const { return step_size_; }
+  intptr_t bytes_to_next_step() const { return bytes_to_next_step_; }
 
   // Pure virtual method provided by the subclasses that gets called when more
   // than step_size byte have been allocated.
   virtual void Step(int bytes_allocated) = 0;
 
   // Called each time the new space does an inline allocation step. This may be
   // more frequently than the step_size we are monitoring (e.g. when there are
   // multiple observers, or when page or space boundary is encountered.) The
   // Step method is only called once more than step_size bytes have been
   // allocated.
@@ skipping 20 matching lines @@
 // forwards most functions to the appropriate semispace.
 
 class NewSpace : public Space {
  public:
   // Constructor.
   explicit NewSpace(Heap* heap)
       : Space(heap, NEW_SPACE, NOT_EXECUTABLE),
         to_space_(heap, kToSpace),
         from_space_(heap, kFromSpace),
         reservation_(),
-        inline_allocation_limit_step_(0),
         top_on_previous_step_(0) {}
 
   // Sets up the new space using the given chunk.
   bool SetUp(int reserved_semispace_size_, int max_semi_space_size);
 
   // Tears down the space.  Heap memory was not allocated by the space, so it
   // is not deallocated here.
   void TearDown();
 
   // True if the space has been set up but not torn down.
@@ skipping 153 matching lines @@
   MUST_USE_RESULT INLINE(
       AllocationResult AllocateRawUnaligned(int size_in_bytes));
 
   MUST_USE_RESULT INLINE(AllocationResult AllocateRaw(
       int size_in_bytes, AllocationAlignment alignment));
 
   // Reset the allocation pointer to the beginning of the active semispace.
   void ResetAllocationInfo();
 
   void UpdateInlineAllocationLimit(int size_in_bytes);
-  void UpdateInlineAllocationLimitStep();
+  void StartNextInlineAllocationStep();
 
   // Allows observation of inline allocation. The observer->Step() method gets
   // called after every step_size bytes have been allocated (approximately).
   // This works by adjusting the allocation limit to a lower value and adjusting
   // it after each step.
   void AddInlineAllocationObserver(InlineAllocationObserver* observer);
 
   // Removes a previously installed observer.
   void RemoveInlineAllocationObserver(InlineAllocationObserver* observer);
 
   void DisableInlineAllocationSteps() {
-    inline_allocation_limit_step_ = 0;
     top_on_previous_step_ = 0;
     UpdateInlineAllocationLimit(0);
   }
 
   // Get the extent of the inactive semispace (for use as a marking stack,
   // or to zap it). Notice: space-addresses are not necessarily on the
   // same page, so FromSpaceStart() might be above FromSpaceEnd().
   Address FromSpacePageLow() { return from_space_.page_low(); }
   Address FromSpacePageHigh() { return from_space_.page_high(); }
   Address FromSpaceStart() { return from_space_.space_start(); }
@@ skipping 81 matching lines @@
 
   // Allocation pointer and limit for normal allocation and allocation during
   // mark-compact collection.
   AllocationInfo allocation_info_;
 
   // When inline allocation stepping is active, either because of incremental
   // marking or because of idle scavenge, we 'interrupt' inline allocation every
   // once in a while. This is done by setting allocation_info_.limit to be lower
   // than the actual limit and and increasing it in steps to guarantee that the
   // observers are notified periodically.
-  intptr_t inline_allocation_limit_step_;
   List<InlineAllocationObserver*> inline_allocation_observers_;
 
   Address top_on_previous_step_;
 
   HistogramInfo* allocated_histogram_;
   HistogramInfo* promoted_histogram_;
 
   bool EnsureAllocation(int size_in_bytes, AllocationAlignment alignment);
 
   // If we are doing inline allocation in steps, this method performs the 'step'
   // operation. top is the memory address of the bump pointer at the last
   // inline allocation (i.e. it determines the numbers of bytes actually
   // allocated since the last step.) new_top is the address of the bump pointer
   // where the next byte is going to be allocated from. top and new_top may be
   // different when we cross a page boundary or reset the space.
   void InlineAllocationStep(Address top, Address new_top);
+  intptr_t GetNextInlineAllocationStepSize();
 
   friend class SemiSpaceIterator;
 };
 
 // -----------------------------------------------------------------------------
 // Compaction space that is used temporarily during compaction.
 
 class CompactionSpace : public PagedSpace {
  public:
   CompactionSpace(Heap* heap, AllocationSpace id, Executability executable)
@@ skipping 248 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_