Move idle notification handling to GCIdleTimeHandler.

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 <climits>
 
 #include "src/v8.h"
 
 #include "src/heap/gc-idle-time-handler.h"
 
 namespace v8 {
 namespace internal {
 
-
 const double GCIdleTimeHandler::kConservativeTimeRatio = 0.9;
 
-
 intptr_t GCIdleTimeHandler::EstimateMarkingStepSize(
     int idle_time_in_ms, intptr_t marking_speed_in_bytes_per_ms) {
   DCHECK(idle_time_in_ms > 0);
 
   if (marking_speed_in_bytes_per_ms == 0) {
     marking_speed_in_bytes_per_ms =
         GCIdleTimeHandler::kInitialConservativeMarkingSpeed;
   }
 
   intptr_t marking_step_size = marking_speed_in_bytes_per_ms * idle_time_in_ms;
   if (static_cast<intptr_t>(marking_step_size / idle_time_in_ms) !=
       marking_speed_in_bytes_per_ms) {
     // In the case of an overflow we return maximum marking step size.
     return INT_MAX;
   }
 
   return static_cast<intptr_t>(marking_step_size *
                                GCIdleTimeHandler::kConservativeTimeRatio);
 }
+
+
+int GCIdleTimeHandler::EstimateMarkSweepTime(
+    intptr_t size_of_objects, intptr_t mark_sweep_speed_in_bytes_per_ms) {
+  const intptr_t kInitialConservativeMarkSweepSpeed = 2 * MB;
+  const intptr_t kMaxTimeInMs = 1000000;
+  if (mark_sweep_speed_in_bytes_per_ms == 0) {
+    mark_sweep_speed_in_bytes_per_ms = kInitialConservativeMarkSweepSpeed;
+  }
+  intptr_t result = size_of_objects / mark_sweep_speed_in_bytes_per_ms;
+  return static_cast<int>(Min(result, kMaxTimeInMs));
+}
+
+
+GCIdleTimeAction GCIdleTimeHandler::Compute(int idle_time_in_ms,
+                                            int contexts_disposed,
+                                            intptr_t size_of_objects,
+                                            bool incremental_marking_stopped,
+                                            GCTracer* gc_tracer) {
+  if (IsIdleRoundFinished()) {
+    if (EnoughGarbageSinceLastIdleRound() || contexts_disposed > 0) {
+      StartIdleRound();
+    } else {
+      return GCIdleTimeAction::Nothing();
+    }
+  }
+  if (incremental_marking_stopped) {
+    intptr_t speed = gc_tracer->MaxMarkSweepSpeedInBytesPerMillisecond();

[Hannes Payer (out of office), 2014/08/20 18:24:11]

Why are we taking the maximum?

[ulan, 2014/08/21 08:45:19]

Good catch, it should be either minimum or average. Made average to be
consistent with other estimates.

+    if (idle_time_in_ms >= EstimateMarkSweepTime(size_of_objects, speed)) {
+      // If there are no more than two GCs left in this idle round and we are
+      // allowed to do a full GC, then make those GCs full in order to compact
+      // the code space.
+      // TODO(ulan): Once we enable code compaction for incremental marking, we
+      // can get rid of this special case and always start incremental marking.
+      int remaining_mark_sweeps =
+          kMaxMarkSweepsInIdleRound - mark_sweeps_since_idle_round_started_;
+      if (contexts_disposed > 0 || remaining_mark_sweeps <= 2) {
+        return GCIdleTimeAction::FullGC();
+      }
+    }
+  }
+  intptr_t speed = gc_tracer->IncrementalMarkingSpeedInBytesPerMillisecond();
+  intptr_t step_size = EstimateMarkingStepSize(idle_time_in_ms, speed);
+  return GCIdleTimeAction::IncrementalMarking(step_size);
 }
 }
+}