Simplify timeline backend

runtime/vm/timeline.h

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_TIMELINE_H_
 #define VM_TIMELINE_H_
 
 #include "vm/allocation.h"
 #include "vm/bitfield.h"
 #include "vm/os.h"
@@ skipping 31 matching lines @@
   // Shutdown timeline system. Not thread safe.
   static void Shutdown();
 
   // Access the global recorder. Not thread safe.
   static TimelineEventRecorder* recorder();
 
   static bool EnableStreamByDefault(const char* stream_name);
 
   static TimelineStream* GetVMStream();
 
-  // Reclaim all |TimelineEventBlock|s that are owned by the current isolate.
-  static void ReclaimIsolateBlocks();
-
-  // Reclaim all |TimelineEventBlocks|s that are owned by all isolates and
-  // the global block owned by the VM.
-  static void ReclaimAllBlocks();
+  // Reclaim all |TimelineEventBlocks|s that are cached by threads.
+  static void ReclaimCachedBlocksFromThreads();
 
 #define ISOLATE_TIMELINE_STREAM_FLAGS(name, not_used)                          \
   static const bool* Stream##name##EnabledFlag() {                             \
     return &stream_##name##_enabled_;                                          \
   }                                                                            \
   static void SetStream##name##Enabled(bool enabled) {                         \
     stream_##name##_enabled_ = enabled;                                        \
   }
   ISOLATE_TIMELINE_STREAM_LIST(ISOLATE_TIMELINE_STREAM_FLAGS)
 #undef ISOLATE_TIMELINE_STREAM_FLAGS
 
  private:
-  static void ReclaimBlocksForIsolate(Isolate* isolate);
-
   static TimelineEventRecorder* recorder_;
   static TimelineStream* vm_stream_;
 
 #define ISOLATE_TIMELINE_STREAM_DECLARE_FLAG(name, not_used)                   \
   static bool stream_##name##_enabled_;
   ISOLATE_TIMELINE_STREAM_LIST(ISOLATE_TIMELINE_STREAM_DECLARE_FLAG)
 #undef ISOLATE_TIMELINE_STREAM_DECLARE_FLAG
 
   friend class TimelineRecorderOverride;
   friend class ReclaimBlocksIsolateVisitor;
@@ skipping 162 matching lines @@
 
   void StreamInit(TimelineStream* stream);
   void Init(EventType event_type, const char* label);
 
   void set_event_type(EventType event_type) {
     // We only reserve 4 bits to hold the event type.
     COMPILE_ASSERT(kNumEventTypes < 16);
     state_ = EventTypeField::update(event_type, state_);
   }
 
-  void set_global_block(bool global_block) {
-    state_ = GlobalBlockField::update(global_block, state_);
-  }
-
-  bool global_block() const {
-    return GlobalBlockField::decode(state_);
-  }
-
   enum StateBits {
     kEventTypeBit = 0,  // reserve 4 bits for type.
-    // Was this event allocated from the global block?
-    kGlobalBlockBit = 4,
-    kNextBit = 5,
+    kNextBit = 4,
   };
 
   class EventTypeField : public BitField<EventType, kEventTypeBit, 4> {};
-  class GlobalBlockField : public BitField<bool, kGlobalBlockBit, 1> {};
 
   friend class TimelineEventRecorder;
   friend class TimelineEventEndlessRecorder;
   friend class TimelineEventRingRecorder;
   friend class TimelineStream;
   friend class TimelineTestHelper;
   DISALLOW_COPY_AND_ASSIGN(TimelineEvent);
 };
 
 
@@ skipping 283 matching lines @@
   virtual TimelineEvent* StartEvent() = 0;
   virtual void CompleteEvent(TimelineEvent* event) = 0;
   virtual TimelineEventBlock* GetHeadBlockLocked() = 0;
   virtual TimelineEventBlock* GetNewBlockLocked(Isolate* isolate) = 0;
   virtual intptr_t NumDartEventsLocked() = 0;
   virtual DartTimelineEvent* DartEventAtLocked(intptr_t i) = 0;
 
   // Utility method(s).
   void PrintJSONMeta(JSONArray* array) const;
   TimelineEvent* ThreadBlockStartEvent();
-  TimelineEvent* GlobalBlockStartEvent();
   void ThreadBlockCompleteEvent(TimelineEvent* event);
-  void GlobalBlockCompleteEvent(TimelineEvent* event);
 
   Mutex lock_;
-  // Only accessed under |lock_|.
-  TimelineEventBlock* global_block_;
-  void ReclaimGlobalBlock();
-
   uintptr_t async_id_;
 
   friend class DartTimelineEventIterator;
   friend class TimelineEvent;
   friend class TimelineEventBlockIterator;
   friend class TimelineStream;
   friend class TimelineTestHelper;
   friend class Timeline;
 
  private:
@@ skipping 144 matching lines @@
 
  private:
   intptr_t cursor_;
   intptr_t num_events_;
   TimelineEventRecorder* recorder_;
 };
 
 }  // namespace dart
 
 #endif  // VM_TIMELINE_H_