Allocation sampling for paged/lo spaces

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"
 #include "src/base/bits.h"
 #include "src/base/platform/mutex.h"
 #include "src/flags.h"
 #include "src/hashmap.h"
 #include "src/list.h"
 #include "src/objects.h"
 #include "src/utils.h"
 
 namespace v8 {
 namespace internal {
 
+class AllocationObserver;
 class CompactionSpaceCollection;
-class InlineAllocationObserver;
 class Isolate;
 
 // -----------------------------------------------------------------------------
 // Heap structures:
 //
 // A JS heap consists of a young generation, an old generation, and a large
 // object space. The young generation is divided into two semispaces. A
 // scavenger implements Cheney's copying algorithm. The old generation is
 // separated into a map space and an old object space. The map space contains
 // all (and only) map objects, the rest of old objects go into the old space.
@@ skipping 916 matching lines @@
 
   friend class MemoryAllocator;
 };
 
 
 // ----------------------------------------------------------------------------
 // Space is the abstract superclass for all allocation spaces.
 class Space : public Malloced {
  public:
   Space(Heap* heap, AllocationSpace id, Executability executable)
-      : heap_(heap),
+      : allocation_observers_paused_(false),

[ofrobots, 2016/01/26 00:38:25]

As per suggestion above, it might make sense for Heap to own this boolean flag
rather than each space. They should all be paused, or none.

[mattloring, 2016/01/30 00:38:03]

This is currently enforced by the PauseAllocationObserverScope. This will be
further refactored in a follow on to aggregate all observers of the spaces and
handle them uniformly.

+        heap_(heap),
         id_(id),
         executable_(executable),
         committed_(0),
         max_committed_(0) {}
 
   virtual ~Space() {}
 
   Heap* heap() const { return heap_; }
 
   // Does the space need executable memory?
   Executability executable() { return executable_; }
 
   // Identity used in error reporting.
   AllocationSpace identity() { return id_; }
 
+  virtual void AddAllocationObserver(AllocationObserver* observer) {
+    allocation_observers_->Add(observer);
+  }
+
+  virtual void RemoveAllocationObserver(AllocationObserver* observer) {
+    bool removed = allocation_observers_->RemoveElement(observer);
+    static_cast<void>(removed);
+    DCHECK(removed);
+  }
+
+  virtual void PauseAllocationObservers() {
+    allocation_observers_paused_ = true;
+  }
+
+  virtual void ResumeAllocationObservers() {
+    allocation_observers_paused_ = false;
+  }
+
+  void AllocationStep(Address soon_object, int size);
+
   // Return the total amount committed memory for this space, i.e., allocatable
   // memory and page headers.
   virtual intptr_t CommittedMemory() { return committed_; }
 
   virtual intptr_t MaximumCommittedMemory() { return max_committed_; }
 
   // Returns allocated size.
   virtual intptr_t Size() = 0;
 
   // Returns size of objects. Can differ from the allocated size
@@ skipping 26 matching lines @@
       max_committed_ = committed_;
     }
   }
 
   void AccountUncommitted(intptr_t bytes) {
     DCHECK_GE(bytes, 0);
     committed_ -= bytes;
     DCHECK_GE(committed_, 0);
   }
 
+  List<AllocationObserver*>* allocation_observers_ =
+      new List<AllocationObserver*>();
+  bool allocation_observers_paused_;
+
  private:
   Heap* heap_;
   AllocationSpace id_;
   Executability executable_;
 
   // Keeps track of committed memory in a space.
   intptr_t committed_;
   intptr_t max_committed_;
 };
 
@@ skipping 1535 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_(),
-        top_on_previous_step_(0),
-        inline_allocation_observers_paused_(false) {}
+        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.
   bool HasBeenSetUp() {
@@ skipping 156 matching lines @@
       int size_in_bytes, AllocationAlignment alignment));
 
   MUST_USE_RESULT inline AllocationResult AllocateRawSynchronized(
       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);
 
-  // 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() {
     top_on_previous_step_ = 0;
     UpdateInlineAllocationLimit(0);
   }
 
+  void AddAllocationObserver(AllocationObserver* observer) override;
+
+  void RemoveAllocationObserver(AllocationObserver* observer) override;
+
   // 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(); }
   Address FromSpaceEnd() { return from_space_.space_end(); }
 
   // Get the extent of the active semispace's pages' memory.
   Address ToSpaceStart() { return to_space_.space_start(); }
@@ skipping 75 matching lines @@
   // Start address and bit mask for containment testing.
   Address start_;
   uintptr_t address_mask_;
   uintptr_t object_mask_;
   uintptr_t object_expected_;
 
   // 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.
-  List<InlineAllocationObserver*> inline_allocation_observers_;
   Address top_on_previous_step_;
-  bool inline_allocation_observers_paused_;
 
   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, Address soon_object,
                             size_t size);
   intptr_t GetNextInlineAllocationStepSize();
   void StartNextInlineAllocationStep();
-  void PauseInlineAllocationObservers();
-  void ResumeInlineAllocationObservers();
+  void PauseAllocationObservers() override;
+  void ResumeAllocationObservers() override;
 
   friend class PauseInlineAllocationObserversScope;
   friend class SemiSpaceIterator;
 };
 
-class PauseInlineAllocationObserversScope {
+class PauseAllocationObserversScope {
  public:
-  explicit PauseInlineAllocationObserversScope(NewSpace* new_space)
-      : new_space_(new_space) {
-    new_space_->PauseInlineAllocationObservers();
+  explicit PauseAllocationObserversScope(Space* space) : space_(space) {
+    space_->PauseAllocationObservers();
   }
-  ~PauseInlineAllocationObserversScope() {
-    new_space_->ResumeInlineAllocationObservers();
-  }
+  ~PauseAllocationObserversScope() { space_->ResumeAllocationObservers(); }
 
  private:
-  NewSpace* new_space_;
-  DISALLOW_COPY_AND_ASSIGN(PauseInlineAllocationObserversScope);
+  Space* space_;
+  DISALLOW_COPY_AND_ASSIGN(PauseAllocationObserversScope);
 };
 
 // -----------------------------------------------------------------------------
 // Compaction space that is used temporarily during compaction.
 
 class CompactionSpace : public PagedSpace {
  public:
   CompactionSpace(Heap* heap, AllocationSpace id, Executability executable)
       : PagedSpace(heap, id, executable) {}
 
@@ skipping 246 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_