🏄 [heap] Add page evacuation mode for new->old

test/cctest/heap/test-heap.cc

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@@ skipping 3539 matching lines @@
   // The optimizer can allocate stuff, messing up the test.
   i::FLAG_crankshaft = false;
   i::FLAG_always_opt = false;
   // Parallel compaction increases fragmentation, depending on how existing
   // memory is distributed. Since this is non-deterministic because of
   // concurrent sweeping, we disable it for this test.
   i::FLAG_parallel_compaction = false;
   // Concurrent sweeping adds non determinism, depending on when memory is
   // available for further reuse.
   i::FLAG_concurrent_sweeping = false;
+  // Fast evacuation of pages may result in a different page count in old space.
+  // Setting to 101% effectively disables this feature.
+  i::FLAG_page_evacuation_threshold = 101;

[Hannes Payer (out of office), 2016/04/08 10:42:40]

That is not very nice... should we introduce a separate flag for that?

[Michael Lippautz, 2016/04/08 11:30:00]

Done.

   CcTest::InitializeVM();
   Isolate* isolate = CcTest::i_isolate();
   Factory* factory = isolate->factory();
   Heap* heap = isolate->heap();
   v8::HandleScope scope(CcTest::isolate());
   static const int number_of_test_pages = 20;
 
   // Prepare many pages with low live-bytes count.
   PagedSpace* old_space = heap->old_space();
   CHECK_EQ(1, old_space->CountTotalPages());
@@ skipping 3031 matching lines @@
       heap->RightTrimFixedArray<Heap::CONCURRENT_TO_SWEEPER>(arrays[j], N - 1);
     }
   }
   // Force allocation from the free list.
   heap->set_force_oom(true);
   heap->CollectGarbage(OLD_SPACE);
 }
 
 }  // namespace internal
 }  // namespace v8