Reduce context disposal gc overhead.

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 124 matching lines @@
 
 bool GCIdleTimeHandler::ShouldDoMarkCompact(
     size_t idle_time_in_ms, size_t size_of_objects,
     size_t mark_compact_speed_in_bytes_per_ms) {
   return idle_time_in_ms >=
          EstimateMarkCompactTime(size_of_objects,
                                  mark_compact_speed_in_bytes_per_ms);
 }
 
 
+bool GCIdleTimeHandler::ShouldDoContextDisposalMarkCompact(
+    bool context_disposed, double contexts_disposal_rate) {
+  return context_disposed && contexts_disposal_rate > 0 &&
+         contexts_disposal_rate < kHighContextDisposalRate;
+}
+
+
 // 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
 // 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.
 // (6) If incremental marking is in progress, we perform a marking step. Note,
 // that this currently may trigger a full garbage collection.
 GCIdleTimeAction GCIdleTimeHandler::Compute(size_t idle_time_in_ms,
                                             HeapState heap_state) {
   if (idle_time_in_ms == 0) {
     if (heap_state.incremental_marking_stopped) {
-      if (heap_state.contexts_disposed > 0 &&
-          heap_state.contexts_disposal_rate < kHighContextDisposalRate) {
+      if (ShouldDoContextDisposalMarkCompact(
+              heap_state.contexts_disposed,
+              heap_state.contexts_disposal_rate)) {
         return GCIdleTimeAction::FullGC();
       }
     }
     return GCIdleTimeAction::Nothing();
   }
 
   if (ShouldDoScavenge(
           idle_time_in_ms, heap_state.new_space_capacity,
           heap_state.used_new_space_size,
           heap_state.scavenge_speed_in_bytes_per_ms,
@@ skipping 38 matching lines @@
   if (heap_state.incremental_marking_stopped &&
       !heap_state.can_start_incremental_marking) {
     return GCIdleTimeAction::Nothing();
   }
   size_t step_size = EstimateMarkingStepSize(
       idle_time_in_ms, heap_state.incremental_marking_speed_in_bytes_per_ms);
   return GCIdleTimeAction::IncrementalMarking(step_size);
 }
 }
 }