Reland "Allow compaction when incremental marking is on."

src/heap/incremental-marking.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/heap/incremental-marking.h"
 
 #include "src/code-stubs.h"
 #include "src/compilation-cache.h"
@@ skipping 450 matching lines @@
         Object* e = stubs->ValueAt(i);
         if (e->IsCode()) {
           RecordWriteStub::Patch(Code::cast(e), mode);
         }
       }
     }
   }
 }
 
 
-void IncrementalMarking::Start(CompactionFlag flag) {
+void IncrementalMarking::Start() {
   if (FLAG_trace_incremental_marking) {
     PrintF("[IncrementalMarking] Start\n");
   }
   DCHECK(FLAG_incremental_marking);
   DCHECK(FLAG_incremental_marking_steps);
   DCHECK(state_ == STOPPED);
   DCHECK(heap_->gc_state() == Heap::NOT_IN_GC);
   DCHECK(!heap_->isolate()->serializer_enabled());
 
   ResetStepCounters();
 
   was_activated_ = true;
 
   if (!heap_->mark_compact_collector()->sweeping_in_progress()) {
-    StartMarking(flag);
+    StartMarking();
   } else {
     if (FLAG_trace_incremental_marking) {
       PrintF("[IncrementalMarking] Start sweeping.\n");
     }
     state_ = SWEEPING;
   }
 
   heap_->new_space()->LowerInlineAllocationLimit(kAllocatedThreshold);
 }
 
 
-void IncrementalMarking::StartMarking(CompactionFlag flag) {
+void IncrementalMarking::StartMarking() {
   if (FLAG_trace_incremental_marking) {
     PrintF("[IncrementalMarking] Start marking\n");
   }
 
-  is_compacting_ = !FLAG_never_compact && (flag == ALLOW_COMPACTION) &&
+  is_compacting_ = !FLAG_never_compact &&
                    heap_->mark_compact_collector()->StartCompaction(
                        MarkCompactCollector::INCREMENTAL_COMPACTION);
 
   state_ = MARKING;
 
   RecordWriteStub::Mode mode = is_compacting_
                                    ? RecordWriteStub::INCREMENTAL_COMPACTION
                                    : RecordWriteStub::INCREMENTAL;
 
   PatchIncrementalMarkingRecordWriteStubs(heap_, mode);
@@ skipping 313 matching lines @@
 
 void IncrementalMarking::Epilogue() {
   was_activated_ = false;
   weak_closure_was_overapproximated_ = false;
   weak_closure_approximation_rounds_ = 0;
 }
 
 
 void IncrementalMarking::OldSpaceStep(intptr_t allocated) {
   if (IsStopped() && ShouldActivate()) {
-    // TODO(hpayer): Let's play safe for now, but compaction should be
-    // in principle possible.
-    Start(PREVENT_COMPACTION);
+    Start();
   } else {
     Step(allocated * kFastMarking / kInitialMarkingSpeed, GC_VIA_STACK_GUARD);
   }
 }
 
 
 void IncrementalMarking::SpeedUp() {
   bool speed_up = false;
 
   if ((steps_count_ % kMarkingSpeedAccellerationInterval) == 0) {
@@ skipping 108 matching lines @@
     bytes_scanned_ += bytes_to_process;
 
     if (state_ == SWEEPING) {
       if (heap_->mark_compact_collector()->sweeping_in_progress() &&
           (heap_->mark_compact_collector()->IsSweepingCompleted() ||
            !heap_->concurrent_sweeping_enabled())) {
         heap_->mark_compact_collector()->EnsureSweepingCompleted();
       }
       if (!heap_->mark_compact_collector()->sweeping_in_progress()) {
         bytes_scanned_ = 0;
-        StartMarking(PREVENT_COMPACTION);
+        StartMarking();
       }
     } else if (state_ == MARKING) {
       bytes_processed = ProcessMarkingDeque(bytes_to_process);
       if (heap_->mark_compact_collector()->marking_deque()->IsEmpty()) {
         if (completion == FORCE_COMPLETION ||
             IsIdleMarkingDelayCounterLimitReached()) {
           if (FLAG_overapproximate_weak_closure &&
               !weak_closure_was_overapproximated_) {
             OverApproximateWeakClosure(action);
           } else {
@@ skipping 48 matching lines @@
 void IncrementalMarking::IncrementIdleMarkingDelayCounter() {
   idle_marking_delay_counter_++;
 }
 
 
 void IncrementalMarking::ClearIdleMarkingDelayCounter() {
   idle_marking_delay_counter_ = 0;
 }
 }
 }  // namespace v8::internal