[oilpan]: Attempt to make allocation faster by only updating the GC stats when needed, rather than …

Source/platform/heap/Heap.h

Index: Source/platform/heap/Heap.h
diff --git a/Source/platform/heap/Heap.h b/Source/platform/heap/Heap.h
index 0b1e891d2f1e70a9d12b7d8407b2456f3a5896f9..41b02d2d0b060e34c77c82472a1b8495eb26d74d 100644
--- a/Source/platform/heap/Heap.h
+++ b/Source/platform/heap/Heap.h
@@ -911,7 +911,9 @@ private:
         ASSERT(!point || heapPageFromAddress(point));
         ASSERT(size <= HeapPage<Header>::payloadSize());
         m_currentAllocationPoint = point;
-        m_remainingAllocationSize = size;
+        if (m_lastRemainingAllocationSize != m_remainingAllocationSize)
+            stats().increaseObjectSpace(m_lastRemainingAllocationSize-m_remainingAllocationSize);
+        m_lastRemainingAllocationSize = m_remainingAllocationSize = size;
     }
     void ensureCurrentAllocation(size_t, const GCInfo*);
     bool allocateFromFreeList(size_t);
@@ -930,6 +932,7 @@ private:
 
     Address m_currentAllocationPoint;
     size_t m_remainingAllocationSize;
+    size_t m_lastRemainingAllocationSize;
 
     HeapPage<Header>* m_firstPage;
     LargeHeapObject<Header>* m_firstLargeHeapObject;
@@ -1454,26 +1457,24 @@ template<typename Header>
 Address ThreadHeap<Header>::allocate(size_t size, const GCInfo* gcInfo)
 {
     size_t allocationSize = allocationSizeFromSize(size);
-    bool isLargeObject = allocationSize > blinkPageSize / 2;
-    if (isLargeObject)
-        return allocateLargeObject(allocationSize, gcInfo);
-    if (m_remainingAllocationSize < allocationSize)
-        return outOfLineAllocate(size, gcInfo);
-    Address headerAddress = m_currentAllocationPoint;
-    m_currentAllocationPoint += allocationSize;
-    m_remainingAllocationSize -= allocationSize;
-    Header* header = new (NotNull, headerAddress) Header(allocationSize, gcInfo);
-    size_t payloadSize = allocationSize - sizeof(Header);
-    stats().increaseObjectSpace(payloadSize);
-    Address result = headerAddress + sizeof(*header);
-    ASSERT(!(reinterpret_cast<uintptr_t>(result) & allocationMask));
-    // Unpoison the memory used for the object (payload).
-    ASAN_UNPOISON_MEMORY_REGION(result, payloadSize);
+    if (allocationSize <= m_remainingAllocationSize) {
+        Address headerAddress = m_currentAllocationPoint;
+        m_currentAllocationPoint += allocationSize;
+        m_remainingAllocationSize -= allocationSize;
+        Header* header = new (NotNull, headerAddress) Header(allocationSize, gcInfo);
+        Address result = headerAddress + sizeof(*header);
+        ASSERT(!(reinterpret_cast<uintptr_t>(result) & allocationMask));
+
+        // Unpoison the memory used for the object (payload).
+        ASAN_UNPOISON_MEMORY_REGION(result, allocationSize - sizeof(Header));
 #if ENABLE(ASSERT) || defined(LEAK_SANITIZER) || defined(ADDRESS_SANITIZER)
-    memset(result, 0, payloadSize);
+        memset(result, 0, allocationSize - sizeof(Header));
 #endif
-    ASSERT(heapPageFromAddress(headerAddress + allocationSize - 1));
-    return result;
+        ASSERT(heapPageFromAddress(headerAddress + allocationSize - 1));
+        return result;
+    }
+    ASSERT(allocationSize > m_remainingAllocationSize);
+    return outOfLineAllocate(size, gcInfo);
 }
 
 template<typename T, typename HeapTraits>