Tune the memory pressure handler to perform a second GC immediately

test/cctest/heap/test-heap.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 6743 matching lines @@
     }
   }
   CHECK(marking->IsComplete());
   intptr_t size_before = heap->SizeOfObjects();
   CcTest::heap()->CollectAllGarbage();
   intptr_t size_after = heap->SizeOfObjects();
   // Live size does not increase after garbage collection.
   CHECK_LE(size_after, size_before);
 }
 
+TEST(Regress618958) {
+  CcTest::InitializeVM();
+  v8::HandleScope scope(CcTest::isolate());
+  Heap* heap = CcTest::heap();
+  bool isolate_is_locked = true;
+  heap->update_amount_of_external_allocated_memory(100 * MB);
+  int mark_sweep_count_before = heap->ms_count();
+  heap->MemoryPressureNotification(MemoryPressureLevel::kCritical,
+                                   isolate_is_locked);
+  int mark_sweep_count_after = heap->ms_count();
+  int mark_sweeps_performed = mark_sweep_count_after - mark_sweep_count_before;
+  // The memory pressuer handler either performed two GCs or performed one and
+  // started incremental marking.
+  CHECK(mark_sweeps_performed == 2 ||
+        (mark_sweeps_performed == 1 &&
+         !heap->incremental_marking()->IsStopped()));
+}
+
 }  // namespace internal
 }  // namespace v8