[heap] Optimize NewSpace::AllocatedSinceLastGC

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 524 matching lines @@
   static const int kAllocatableMemory = kPageSize - kObjectStartOffset;
 
   static inline void IncrementLiveBytesFromMutator(HeapObject* object, int by);
   static inline void IncrementLiveBytesFromGC(HeapObject* object, int by);
 
   // Only works if the pointer is in the first kPageSize of the MemoryChunk.
   static MemoryChunk* FromAddress(Address a) {
     return reinterpret_cast<MemoryChunk*>(OffsetFrom(a) & ~kAlignmentMask);
   }
 
+  static intptr_t OffsetInPage(Address a) {
+    return reinterpret_cast<intptr_t>(a) & kPageAlignmentMask;
+  }
+
   static inline MemoryChunk* FromAnyPointerAddress(Heap* heap, Address addr);
 
   static inline void UpdateHighWaterMark(Address mark) {
     if (mark == nullptr) return;
     // Need to subtract one from the mark because when a chunk is full the
     // top points to the next address after the chunk, which effectively belongs
     // to another chunk. See the comment to Page::FromAllocationTop.
     MemoryChunk* chunk = MemoryChunk::FromAddress(mark - 1);
     intptr_t new_mark = static_cast<intptr_t>(mark - chunk->address());
     intptr_t old_mark = 0;
@@ skipping 2020 matching lines @@
 // forwards most functions to the appropriate semispace.
 
 class NewSpace : public Space {
  public:
   explicit NewSpace(Heap* heap)
       : Space(heap, NEW_SPACE, NOT_EXECUTABLE),
         to_space_(heap, kToSpace),
         from_space_(heap, kFromSpace),
         reservation_(),
         pages_used_(0),
+        allocated_since_last_gc_(0),
         top_on_previous_step_(0),
         allocated_histogram_(nullptr),
         promoted_histogram_(nullptr) {}
 
   inline bool Contains(HeapObject* o);
   inline bool ContainsSlow(Address a);
   inline bool Contains(Object* o);
 
   bool SetUp(int initial_semispace_capacity, int max_semispace_capacity);
 
@@ skipping 51 matching lines @@
     return from_space_.MaximumCommittedMemory() +
            to_space_.MaximumCommittedMemory();
   }
 
   // Approximate amount of physical memory committed for this space.
   size_t CommittedPhysicalMemory() override;
 
   // Return the available bytes without growing.
   intptr_t Available() override { return Capacity() - Size(); }
 
-  size_t AllocatedSinceLastGC() {
-    bool seen_age_mark = false;
-    Address age_mark = to_space_.age_mark();
-    NewSpacePage* current_page = to_space_.first_page();
-    NewSpacePage* age_mark_page = NewSpacePage::FromAddress(age_mark);
-    NewSpacePage* last_page = NewSpacePage::FromAddress(top() - kPointerSize);
-    if (age_mark_page == last_page) {
-      if (top() - age_mark >= 0) {
-        return top() - age_mark;
-      }
-      // Top was reset at some point, invalidating this metric.
-      return 0;
-    }
-    while (current_page != last_page) {
-      if (current_page == age_mark_page) {
-        seen_age_mark = true;
-        break;
-      }
-      current_page = current_page->next_page();
-    }
-    if (!seen_age_mark) {
-      // Top was reset at some point, invalidating this metric.
-      return 0;
-    }
-    intptr_t allocated = age_mark_page->area_end() - age_mark;
-    DCHECK_EQ(current_page, age_mark_page);
-    current_page = age_mark_page->next_page();
-    while (current_page != last_page) {
-      allocated += NewSpacePage::kAllocatableMemory;
-      current_page = current_page->next_page();
-    }
-    allocated += top() - current_page->area_start();
-    DCHECK_LE(0, allocated);
-    DCHECK_LE(allocated, Size());
-    return static_cast<size_t>(allocated);
-  }
+  inline size_t AllocatedSinceLastGC();
 
   // Return the maximum capacity of a semispace.
   int MaximumCapacity() {
     DCHECK(to_space_.maximum_capacity() == from_space_.maximum_capacity());
     return to_space_.maximum_capacity();
   }
 
   bool IsAtMaximumCapacity() { return TotalCapacity() == MaximumCapacity(); }
 
   // Returns the initial capacity of a semispace.
@@ skipping 13 matching lines @@
     DCHECK(to_space_.current_page()->ContainsLimit(allocation_info_.limit()));
     return allocation_info_.limit();
   }
 
   // Return the address of the first object in the active semispace.
   Address bottom() { return to_space_.space_start(); }
 
   // Get the age mark of the inactive semispace.
   Address age_mark() { return from_space_.age_mark(); }
   // Set the age mark in the active semispace.
-  void set_age_mark(Address mark) { to_space_.set_age_mark(mark); }
+  void set_age_mark(Address mark) {
+    to_space_.set_age_mark(mark);
+    allocated_since_last_gc_ = 0;
+  }
 
   // The allocation top and limit address.
   Address* allocation_top_address() { return allocation_info_.top_address(); }
 
   // The allocation limit address.
   Address* allocation_limit_address() {
     return allocation_info_.limit_address();
   }
 
   MUST_USE_RESULT INLINE(AllocationResult AllocateRawAligned(
@@ skipping 100 matching lines @@
   // Update allocation info to match the current to-space page.
   void UpdateAllocationInfo();
 
   base::Mutex mutex_;
 
   // The semispaces.
   SemiSpace to_space_;
   SemiSpace from_space_;
   base::VirtualMemory reservation_;
   int pages_used_;
+  intptr_t allocated_since_last_gc_;
 
   // Allocation pointer and limit for normal allocation and allocation during
   // mark-compact collection.
   AllocationInfo allocation_info_;
 
   Address top_on_previous_step_;
 
   HistogramInfo* allocated_histogram_;
   HistogramInfo* promoted_histogram_;
 
@@ skipping 259 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_