[heap] Use smaller minimum allocation limit growing step when optimizing for memory usage.

src/heap/heap.h

 // Copyright 2012 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_HEAP_H_
 #define V8_HEAP_HEAP_H_
 
 #include <cmath>
 #include <map>
 
@@ skipping 501 matching lines @@
 
   // Support for partial snapshots.  After calling this we have a linear
   // space to write objects in each space.
   struct Chunk {
     uint32_t size;
     Address start;
     Address end;
   };
   typedef List<Chunk> Reservation;
 
-  static const intptr_t kMinimumOldGenerationAllocationLimit =
-      8 * (Page::kPageSize > MB ? Page::kPageSize : MB);
-
   static const int kInitalOldGenerationLimitFactor = 2;
 
 #if V8_OS_ANDROID
   // Don't apply pointer multiplier on Android since it has no swap space and
   // should instead adapt it's heap size based on available physical memory.
   static const int kPointerMultiplier = 1;
 #else
   static const int kPointerMultiplier = i::kPointerSize / 4;
 #endif
 
@@ skipping 1261 matching lines @@
 
   // Calculates the allocation limit based on a given growing factor and a
   // given old generation size.
   intptr_t CalculateOldGenerationAllocationLimit(double factor,
                                                  intptr_t old_gen_size);
 
   // Sets the allocation limit to trigger the next full garbage collection.
   void SetOldGenerationAllocationLimit(intptr_t old_gen_size, double gc_speed,
                                        double mutator_speed);
 
+  intptr_t MinimumAllocationLimitGrowingStep() {
+    const double kRegularAllocationLimitGrowingStep = 8;
+    const double kLowMemoryAllocationLimitGrowingStep = 2;
+    intptr_t limit = (Page::kPageSize > MB ? Page::kPageSize : MB);
+    return limit * (ShouldOptimizeForMemoryUsage()
+                        ? kLowMemoryAllocationLimitGrowingStep
+                        : kRegularAllocationLimitGrowingStep);
+  }
+
   // ===========================================================================
   // Idle notification. ========================================================
   // ===========================================================================
 
   bool RecentIdleNotificationHappened();
   void ScheduleIdleScavengeIfNeeded(int bytes_allocated);
 
   // ===========================================================================
   // HeapIterator helpers. =====================================================
   // ===========================================================================
@@ skipping 886 matching lines @@
   friend class LargeObjectSpace;
   friend class NewSpace;
   friend class PagedSpace;
   DISALLOW_COPY_AND_ASSIGN(AllocationObserver);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_HEAP_H_