Reland of "[heap] Switch to 500k pages"

test/cctest/heap/test-spaces.cc

 // Copyright 2011 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 460 matching lines @@
     // The available value is conservative such that it may report
     // zero prior to heap exhaustion.
     CHECK(lo->Available() < available || available == 0);
   }
 
   CHECK(!lo->IsEmpty());
 
   CHECK(lo->AllocateRaw(lo_size, NOT_EXECUTABLE).IsRetry());
 }
 
-
-TEST(SizeOfFirstPageIsLargeEnough) {
+TEST(SizeOfInitialHeap) {
   if (i::FLAG_always_opt) return;
   // Bootstrapping without a snapshot causes more allocations.
   CcTest::InitializeVM();
   Isolate* isolate = CcTest::i_isolate();
   if (!isolate->snapshot_available()) return;
   HandleScope scope(isolate);
   v8::Local<v8::Context> context = CcTest::isolate()->GetCurrentContext();
   // Skip this test on the custom snapshot builder.
   if (!CcTest::global()
            ->Get(context, v8_str("assertEquals"))
            .ToLocalChecked()
            ->IsUndefined()) {
     return;
   }
 
-  // If this test fails due to enabling experimental natives that are not part
-  // of the snapshot, we may need to adjust CalculateFirstPageSizes.
+  // The limit for each space for an empty isolate containing just the
+  // snapshot.
+  const size_t kMaxInitialSizePerSpace = 1536 * KB;  // 1.5MB
 
-  // Freshly initialized VM gets by with one page per space.
+  // Freshly initialized VM gets by with the snapshot size (which is below
+  // kMaxInitialSizePerSpace per space).
+  Heap* heap = isolate->heap();
+  int page_count[LAST_PAGED_SPACE + 1] = {0, 0, 0, 0};
   for (int i = FIRST_PAGED_SPACE; i <= LAST_PAGED_SPACE; i++) {
     // Debug code can be very large, so skip CODE_SPACE if we are generating it.
     if (i == CODE_SPACE && i::FLAG_debug_code) continue;
-    CHECK_EQ(1, isolate->heap()->paged_space(i)->CountTotalPages());
+
+    page_count[i] = heap->paged_space(i)->CountTotalPages();
+    // Check that the initial heap is also below the limit.
+    CHECK_LT(static_cast<size_t>(heap->paged_space(i)->CommittedMemory()),
+             kMaxInitialSizePerSpace);
   }
 
-  // Executing the empty script gets by with one page per space.
+  // Executing the empty script gets by with the same number of pages, i.e.,
+  // requires no extra space.
   CompileRun("/*empty*/");
   for (int i = FIRST_PAGED_SPACE; i <= LAST_PAGED_SPACE; i++) {
     // Debug code can be very large, so skip CODE_SPACE if we are generating it.
     if (i == CODE_SPACE && i::FLAG_debug_code) continue;
-    CHECK_EQ(1, isolate->heap()->paged_space(i)->CountTotalPages());
+    CHECK_EQ(page_count[i], isolate->heap()->paged_space(i)->CountTotalPages());
   }
 
   // No large objects required to perform the above steps.
   CHECK(isolate->heap()->lo_space()->IsEmpty());
 }
 
 static HeapObject* AllocateUnaligned(NewSpace* space, int size) {
   AllocationResult allocation = space->AllocateRawUnaligned(size);
   CHECK(!allocation.IsRetry());
   HeapObject* filler = NULL;
@@ skipping 152 matching lines @@
     new_space->RemoveAllocationObserver(&observer2);
 
     CHECK_EQ(observer1.count(), 32);
     CHECK_EQ(observer2.count(), 28);
   }
   isolate->Dispose();
 }
 
 }  // namespace internal
 }  // namespace v8