Enable non-incremental code compaction.

It is intended to bring memory usage down on idle notifications.

R=erik.corry@gmail.com
BUG=v8:1726

Review URL: https://chromiumcodereview.appspot.com/9323079

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10616 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/flag-definitions.h

@@ -307,7 +307,6 @@ DEFINE_bool(cleanup_caches_in_maps_at_gc, true,
             "Flush code caches in maps during mark compact cycle.")
 DEFINE_bool(never_compact, false,
             "Never perform compaction on full GC - testing only")
-DEFINE_bool(compact_code_space, false, "Compact code space")
 DEFINE_bool(cleanup_code_caches_at_gc, true,
             "Flush inline caches prior to mark compact collection and "
             "flush code caches in maps during mark compact cycle.")

src/incremental-marking.cc

@@ -505,7 +505,8 @@ void IncrementalMarking::StartMarking(CompactionFlag flag) {
   }
 
   is_compacting_ = !FLAG_never_compact && (flag == ALLOW_COMPACTION) &&
-      heap_->mark_compact_collector()->StartCompaction();
+      heap_->mark_compact_collector()->StartCompaction(
+          MarkCompactCollector::INCREMENTAL_COMPACTION);
 
   state_ = MARKING;
 

src/mark-compact.cc

@@ -242,14 +242,14 @@ static void TraceFragmentation(PagedSpace* space) {
 }
 
 
-bool MarkCompactCollector::StartCompaction() {
+bool MarkCompactCollector::StartCompaction(CompactionMode mode) {
   if (!compacting_) {
     ASSERT(evacuation_candidates_.length() == 0);
 
     CollectEvacuationCandidates(heap()->old_pointer_space());
     CollectEvacuationCandidates(heap()->old_data_space());
 
-    if (FLAG_compact_code_space) {
+    if (mode == NON_INCREMENTAL_COMPACTION) {
       CollectEvacuationCandidates(heap()->code_space());
     } else if (FLAG_trace_fragmentation) {
       TraceFragmentation(heap()->code_space());
@@ -697,7 +697,7 @@ void MarkCompactCollector::Prepare(GCTracer* tracer) {
   // Don't start compaction if we are in the middle of incremental
   // marking cycle. We did not collect any slots.
   if (!FLAG_never_compact && !was_marked_incrementally_) {
-    StartCompaction();
+    StartCompaction(NON_INCREMENTAL_COMPACTION);
   }
 
   PagedSpaces spaces;

src/mark-compact.h

@@ -441,7 +441,12 @@ class MarkCompactCollector {
   // Performs a global garbage collection.
   void CollectGarbage();
 
-  bool StartCompaction();
+  enum CompactionMode {
+    INCREMENTAL_COMPACTION,
+    NON_INCREMENTAL_COMPACTION
+  };
+
+  bool StartCompaction(CompactionMode mode);
 
   void AbortCompaction();