Make TimelineEventBlocks reclaimable

runtime/vm/timeline.h

Index: runtime/vm/timeline.h
diff --git a/runtime/vm/timeline.h b/runtime/vm/timeline.h
index 335ff14b9ac246ae6094cb0e9c818c8eaf314053..d704e4724cc47191a893ccc0dfd92dbe1a45cccd 100644
--- a/runtime/vm/timeline.h
+++ b/runtime/vm/timeline.h
@@ -45,6 +45,13 @@ class Timeline : public AllStatic {
 
   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();
+
 #define ISOLATE_TIMELINE_STREAM_FLAGS(name, not_used)                          \
   static const bool* Stream##name##EnabledFlag() {                             \
     return &stream_##name##_enabled_;                                          \
@@ -56,6 +63,8 @@ class Timeline : public AllStatic {
 #undef ISOLATE_TIMELINE_STREAM_FLAGS
 
  private:
+  static void ReclaimBlocksForIsolate(Isolate* isolate);
+
   static TimelineEventRecorder* recorder_;
   static TimelineStream* vm_stream_;
 
@@ -65,6 +74,7 @@ class Timeline : public AllStatic {
 #undef ISOLATE_TIMELINE_STREAM_DECLARE_FLAG
 
   friend class TimelineRecorderOverride;
+  friend class ReclaimBlocksIsolateVisitor;
 };
 
 
@@ -461,7 +471,7 @@ class IsolateTimelineEventFilter : public TimelineEventFilter {
       return false;
     }
     // Not empty, not open, and isolate match.
-    return !block->IsEmpty() &&
+    return !block->IsEmpty() && !block->open() &&

[turnidge, 2015/09/24 17:05:52]

Consider in_use instead of open?

[Cutch, 2015/09/24 18:14:16]

Done.

            (block->isolate() == isolate_);
   }
 
@@ -500,7 +510,7 @@ class TimelineEventRecorder {
   Mutex lock_;
   // Only accessed under |lock_|.
   TimelineEventBlock* global_block_;
-  void FinishGlobalBlock();
+  void ReclaimGlobalBlock();
 
   uintptr_t async_id_;