[tracing] Adding task information to heap profiler

base/trace_event/heap_profiler_allocation_context_tracker.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef BASE_TRACE_EVENT_HEAP_PROFILER_ALLOCATION_CONTEXT_TRACKER_H_
 #define BASE_TRACE_EVENT_HEAP_PROFILER_ALLOCATION_CONTEXT_TRACKER_H_
 
 #include <vector>
 
 #include "base/atomicops.h"
 #include "base/base_export.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/trace_event/heap_profiler_allocation_context.h"
 
 namespace base {
 namespace trace_event {
 
 // The allocation context tracker keeps track of thread-local context for heap
 // profiling. It includes a pseudo stack of trace events. On every allocation
 // the tracker provides a snapshot of its context in the form of an
 // |AllocationContext| that is to be stored together with the allocation
 // details.
 class BASE_EXPORT AllocationContextTracker {
  public:
+  class ScopedTaskExecutionEvent {
+   public:
+    ScopedTaskExecutionEvent(const char* category_group,
+                             const char* posted_reason);

[Primiano Tucci (use gerrit), 2016/03/25 01:56:31]

I think these should be called poster_task_file_name and
poster_task_function_name
Also, looks like you never use the 2nd argument, so let's remove it

[ssid, 2016/03/28 18:14:49]

calling it context, can change if you prefer to be more specific. I think if we
decide to use something else in context instead of file name, it need not be
changed.

+
+    ~ScopedTaskExecutionEvent();
+
+   private:
+    const char* category_;
+  };
+
   // Globally enables capturing allocation context.
   // TODO(ruuda): Should this be replaced by |EnableCapturing| in the future?
   // Or at least have something that guards agains enable -> disable -> enable?
   static void SetCaptureEnabled(bool enabled);
 
   // Returns whether capturing allocation context is enabled globally.
   inline static bool capture_enabled() {
     // A little lag after heap profiling is enabled or disabled is fine, it is
     // more important that the check is as cheap as possible when capturing is
     // not enabled, so do not issue a memory barrier in the fast path.
@@ skipping 24 matching lines @@
   // Returns a snapshot of the current thread-local context.
   AllocationContext GetContextSnapshot();
 
   ~AllocationContextTracker();
 
  private:
   AllocationContextTracker();
 
   static subtle::Atomic32 capture_enabled_;
 
+  void PushCurrentCategoryName(const char* category);

[Primiano Tucci (use gerrit), 2016/03/25 01:56:31]

I'm a bit confused by the "Category" name here.
Can we call these just PushPosterTaskName

[ssid, 2016/03/28 18:14:49]

Hm it is not exactly task name. To be specific I should call it
TaskPostedFromFilename. Gets too specific and we can't use it in future if we
wanted to add some other context here. So, i am renaming it to TaskContext, to
keep it generic but still makes enough sense.

+  void PopCurrentCategoryName(const char* category);
+
   // The pseudo stack where frames are |TRACE_EVENT| names.
   std::vector<StackFrame> pseudo_stack_;
 
+  // Category can be nested when tasks are nested. So, a stack is used and the
+  // last item is taken for the current allocation.
+  std::vector<const char*> categories_;
+
   DISALLOW_COPY_AND_ASSIGN(AllocationContextTracker);
 };
 
 }  // namespace trace_event
 }  // namespace base
 
 #endif  // BASE_TRACE_EVENT_HEAP_PROFILER_ALLOCATION_CONTEXT_TRACKER_H_