[heap] Add a guard for restarting the memory reducer after mark-compact.

src/heap/memory-reducer.h

Index: src/heap/memory-reducer.h
diff --git a/src/heap/memory-reducer.h b/src/heap/memory-reducer.h
index 4745001b6ccaca22a9b9701b1176cad522ba852c..5057938d016233258c7a29f671893fb2f0961afa 100644
--- a/src/heap/memory-reducer.h
+++ b/src/heap/memory-reducer.h
@@ -86,15 +86,17 @@ class V8_EXPORT_PRIVATE MemoryReducer {
 
   struct State {
     State(Action action, int started_gcs, double next_gc_start_ms,
-          double last_gc_time_ms)
+          double last_gc_time_ms, size_t committed_memory_at_last_run)
         : action(action),
           started_gcs(started_gcs),
           next_gc_start_ms(next_gc_start_ms),
-          last_gc_time_ms(last_gc_time_ms) {}
+          last_gc_time_ms(last_gc_time_ms),
+          committed_memory_at_last_run(committed_memory_at_last_run) {}
     Action action;
     int started_gcs;
     double next_gc_start_ms;
     double last_gc_time_ms;
+    size_t committed_memory_at_last_run;
   };
 
   enum EventType { kTimer, kMarkCompact, kPossibleGarbage };
@@ -102,6 +104,7 @@ class V8_EXPORT_PRIVATE MemoryReducer {
   struct Event {
     EventType type;
     double time_ms;
+    size_t committed_memory;
     bool next_gc_likely_to_collect_more;
     bool should_start_incremental_gc;
     bool can_start_incremental_gc;
@@ -109,7 +112,7 @@ class V8_EXPORT_PRIVATE MemoryReducer {
 
   explicit MemoryReducer(Heap* heap)
       : heap_(heap),
-        state_(kDone, 0, 0.0, 0.0),
+        state_(kDone, 0, 0.0, 0.0, 0),
         js_calls_counter_(0),
         js_calls_sample_time_ms_(0.0) {}
   // Callbacks.
@@ -126,6 +129,12 @@ class V8_EXPORT_PRIVATE MemoryReducer {
   static const int kShortDelayMs;
   static const int kWatchdogDelayMs;
   static const int kMaxNumberOfGCs;
+  // The committed memory has to increase by at least this factor since the
+  // last run in order to trigger a new run after mark-compact.
+  static const double kCommittedMemoryFactor;
+  // The committed memory has to increase by at least this amount since the
+  // last run in order to trigger a new run after mark-compact.
+  static const size_t kCommittedMemoryDelta;
 
   Heap* heap() { return heap_; }