Make full GC reduce memory footprint an explicit event in the idle notification handler.

src/heap/heap.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/base/bits.h"
 #include "src/base/once.h"
@@ skipping 4515 matching lines @@
   if (!IsHeapIterable()) {
     CollectAllGarbage(kMakeHeapIterableMask, "Heap::MakeHeapIterable");
   }
   if (mark_compact_collector()->sweeping_in_progress()) {
     mark_compact_collector()->EnsureSweepingCompleted();
   }
   DCHECK(IsHeapIterable());
 }
 
 
-void Heap::IdleMarkCompact(const char* message) {
+void Heap::IdleMarkCompact(bool reduce_memory, const char* message) {
   bool uncommit = false;
   if (gc_count_at_last_idle_gc_ == gc_count_) {
     // No GC since the last full GC, the mutator is probably not active.
     isolate_->compilation_cache()->Clear();
     uncommit = true;
   }
-  CollectAllGarbage(kReduceMemoryFootprintMask, message);
+  int flags = reduce_memory ? kReduceMemoryFootprintMask : kNoGCFlags;
+  CollectAllGarbage(flags, message);
   gc_idle_time_handler_.NotifyIdleMarkCompact();
   gc_count_at_last_idle_gc_ = gc_count_;
   if (uncommit) {
     new_space_.Shrink();
     UncommitFromSpace();
   }
 }
 
 
 bool Heap::TryFinalizeIdleIncrementalMarking(
@@ skipping 111 matching lines @@
       }
       break;
     }
     case DO_FULL_GC: {
       if (contexts_disposed_) {
         HistogramTimerScope scope(isolate_->counters()->gc_context());
         CollectAllGarbage(kNoGCFlags, "idle notification: contexts disposed");
         gc_idle_time_handler_.NotifyIdleMarkCompact();
         gc_count_at_last_idle_gc_ = gc_count_;
       } else {
-        IdleMarkCompact("idle notification: finalize idle round");
+        IdleMarkCompact(false, "idle notification: finalize idle round");
       }
       break;
     }
+    case DO_FULL_GC_COMPACT: {
+      IdleMarkCompact(true, "idle notification: reduce memory footprint");
+      break;
+    }
     case DO_SCAVENGE:
       CollectGarbage(NEW_SPACE, "idle notification: scavenge");
       break;
     case DO_FINALIZE_SWEEPING:
       mark_compact_collector()->EnsureSweepingCompleted();
       break;
     case DO_NOTHING:
       break;
   }
 
@@ skipping 1676 matching lines @@
       static_cast<int>(object_sizes_last_time_[index]));
   CODE_AGE_LIST_COMPLETE(ADJUST_LAST_TIME_OBJECT_COUNT)
 #undef ADJUST_LAST_TIME_OBJECT_COUNT
 
   MemCopy(object_counts_last_time_, object_counts_, sizeof(object_counts_));
   MemCopy(object_sizes_last_time_, object_sizes_, sizeof(object_sizes_));
   ClearObjectStats();
 }
 }
 }  // namespace v8::internal