[heap] Change LO space limit to 512k - page header

src/objects.h

 // Copyright 2015 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_OBJECTS_H_
 #define V8_OBJECTS_H_
 
 #include <iosfwd>
 #include <memory>
 
@@ skipping 10566 matching lines @@
   DECLARE_PRINTER(JSArray)
   DECLARE_VERIFIER(JSArray)
 
   // Number of element slots to pre-allocate for an empty array.
   static const int kPreallocatedArrayElements = 4;
 
   // Layout description.
   static const int kLengthOffset = JSObject::kHeaderSize;
   static const int kSize = kLengthOffset + kPointerSize;
 
-  // 600 * KB is the Page::kMaxRegularHeapObjectSize defined in spaces.h which
-  // we do not want to include in objects.h
+  // (512 * KB - 384) is the Page::kMaxRegularHeapObjectSize defined in spaces.h
+  // which we do not want to include in objects.h
   // Note that Page::kMaxRegularHeapObjectSize has to be in sync with
   // kInitialMaxFastElementArray which is checked in a DCHECK in heap.cc.
   static const int kInitialMaxFastElementArray =
-      (600 * KB - FixedArray::kHeaderSize - kSize - AllocationMemento::kSize) /
+      (512 * KB - 384 - FixedArray::kHeaderSize - kSize -
+       AllocationMemento::kSize) /
       kPointerSize;
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(JSArray);
 };
 
 
 Handle<Object> CacheInitialJSArrayMaps(Handle<Context> native_context,
                                        Handle<Map> initial_map);
 
@@ skipping 597 matching lines @@
     }
     return value;
   }
 };
 
 
 }  // NOLINT, false-positive due to second-order macros.
 }  // NOLINT, false-positive due to second-order macros.
 
 #endif  // V8_OBJECTS_H_