Tweak compaction candidate selection to avoid keeping page with low occupancy around.

src/execution.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 859 matching lines @@
 }
 
 
 #endif
 
 MaybeObject* Execution::HandleStackGuardInterrupt() {
   Isolate* isolate = Isolate::Current();
   StackGuard* stack_guard = isolate->stack_guard();
 
   if (stack_guard->IsGCRequest()) {
-    isolate->heap()->CollectAllGarbage(false);
+    isolate->heap()->CollectAllGarbage(false, "StackGuard GC request");
     stack_guard->Continue(GC_REQUEST);
   }
 
   isolate->counters()->stack_interrupts()->Increment();
   if (stack_guard->IsRuntimeProfilerTick()) {
     isolate->counters()->runtime_profiler_ticks()->Increment();
     stack_guard->Continue(RUNTIME_PROFILER_TICK);
     isolate->runtime_profiler()->OptimizeNow();
   }
 #ifdef ENABLE_DEBUGGER_SUPPORT
   if (stack_guard->IsDebugBreak() || stack_guard->IsDebugCommand()) {
     DebugBreakHelper();
   }
 #endif
   if (stack_guard->IsPreempted()) RuntimePreempt();
   if (stack_guard->IsTerminateExecution()) {
     stack_guard->Continue(TERMINATE);
     return isolate->TerminateExecution();
   }
   if (stack_guard->IsInterrupted()) {
     stack_guard->Continue(INTERRUPT);
     return isolate->StackOverflow();
   }
   return isolate->heap()->undefined_value();
 }
 
 } }  // namespace v8::internal