Ensure that GC idle notifications either make progress or stop requesting more GCs.

src/heap/gc-idle-time-handler.cc

 // Copyright 2014 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/heap/gc-idle-time-handler.h"
 #include "src/heap/gc-tracer.h"
 #include "src/utils.h"
 
 namespace v8 {
 namespace internal {
@@ skipping 169 matching lines @@
 }
 
 
 bool GCIdleTimeHandler::ShouldDoOverApproximateWeakClosure(
     size_t idle_time_in_ms) {
   // TODO(jochen): Estimate the time it will take to build the object groups.
   return idle_time_in_ms >= kMinTimeForOverApproximatingWeakClosureInMs;
 }
 
 
+GCIdleTimeAction GCIdleTimeHandler::NothingOrDone() {
+  if (idle_times_which_made_no_progress_since_last_idle_round_ >=
+      kMaxNoProgressIdleTimesPerIdleRound) {
+    return GCIdleTimeAction::Done();
+  } else {
+    idle_times_which_made_no_progress_since_last_idle_round_++;
+    return GCIdleTimeAction::Nothing();
+  }
+}
+
+
 // The following logic is implemented by the controller:
 // (1) If we don't have any idle time, do nothing, unless a context was
 // disposed, incremental marking is stopped, and the heap is small. Then do
 // a full GC.
-// (2) If the new space is almost full and we can affort a Scavenge or if the
+// (2) If the new space is almost full and we can afford a Scavenge or if the
 // next Scavenge will very likely take long, then a Scavenge is performed.
 // (3) If there is currently no MarkCompact idle round going on, we start a
 // new idle round if enough garbage was created. Otherwise we do not perform
 // garbage collection to keep system utilization low.
 // (4) If incremental marking is done, we perform a full garbage collection
 // if  we are allowed to still do full garbage collections during this idle
 // round or if we are not allowed to start incremental marking. Otherwise we
 // do not perform garbage collection to keep system utilization low.
 // (5) If sweeping is in progress and we received a large enough idle time
 // request, we finalize sweeping here.
@@ skipping 31 matching lines @@
     }
   }
 
   if (heap_state.incremental_marking_stopped) {
     if (ShouldDoMarkCompact(static_cast<size_t>(idle_time_in_ms),
                             heap_state.size_of_objects,
                             heap_state.mark_compact_speed_in_bytes_per_ms)) {
       return GCIdleTimeAction::FullGC();
     }
   }
-
-  if (heap_state.sweeping_in_progress && heap_state.sweeping_completed) {
-    return GCIdleTimeAction::FinalizeSweeping();
+  if (heap_state.sweeping_in_progress) {
+    if (heap_state.sweeping_completed) {
+      return GCIdleTimeAction::FinalizeSweeping();
+    } else {
+      return NothingOrDone();
+    }
+  }
+  if (heap_state.incremental_marking_stopped &&
+      !heap_state.can_start_incremental_marking) {
+    return NothingOrDone();
   }
 
-  if (heap_state.incremental_marking_stopped &&
-      !heap_state.can_start_incremental_marking) {
-    return GCIdleTimeAction::Nothing();
-  }
   size_t step_size = EstimateMarkingStepSize(
       static_cast<size_t>(kIncrementalMarkingStepTimeInMs),
       heap_state.incremental_marking_speed_in_bytes_per_ms);
   return GCIdleTimeAction::IncrementalMarking(step_size);
 }
 }
 }