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

BUG=chromium:636331
R=ulan@chromium.org

Review-Url: https://codereview.chromium.org/2289683002
Cr-Commit-Position: refs/heads/master@{#39106}

src/heap/spaces.h

@@ -716,7 +716,7 @@ class Page : public MemoryChunk {
   // account.
   // TODO(hpayer): This limit should be way smaller but we currently have
   // short living objects >256K.
-  static const int kMaxRegularHeapObjectSize = 600 * KB;
+  static const int kMaxRegularHeapObjectSize = 512 * KB - Page::kHeaderSize;
 
   static inline Page* ConvertNewToOld(Page* old_page, PagedSpace* new_owner);
 

src/objects.h

@@ -10584,12 +10584,13 @@ class JSArray: public JSObject {
   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:

test/cctest/test-serialize.cc

@@ -1178,13 +1178,13 @@ TEST(CodeSerializerThreeBigStrings) {
 
   Vector<const uint8_t> source_b =
       ConstructSource(STATIC_CHAR_VECTOR("var b = \""), STATIC_CHAR_VECTOR("b"),
-                      STATIC_CHAR_VECTOR("\";"), 600000);
+                      STATIC_CHAR_VECTOR("\";"), 400000);
   Handle<String> source_b_str =
       f->NewStringFromOneByte(source_b).ToHandleChecked();
 
   Vector<const uint8_t> source_c =
       ConstructSource(STATIC_CHAR_VECTOR("var c = \""), STATIC_CHAR_VECTOR("c"),
-                      STATIC_CHAR_VECTOR("\";"), 500000);
+                      STATIC_CHAR_VECTOR("\";"), 400000);
   Handle<String> source_c_str =
       f->NewStringFromOneByte(source_c).ToHandleChecked();
 
@@ -1217,10 +1217,10 @@ TEST(CodeSerializerThreeBigStrings) {
   v8::Maybe<int32_t> result =
       CompileRun("(a + b).length")
           ->Int32Value(v8::Isolate::GetCurrent()->GetCurrentContext());
-  CHECK_EQ(600000 + 700000, result.FromJust());
+  CHECK_EQ(400000 + 700000, result.FromJust());
   result = CompileRun("(b + c).length")
                ->Int32Value(v8::Isolate::GetCurrent()->GetCurrentContext());
-  CHECK_EQ(500000 + 600000, result.FromJust());
+  CHECK_EQ(400000 + 400000, result.FromJust());
   Heap* heap = isolate->heap();
   v8::Local<v8::String> result_str =
       CompileRun("a")