Allocation sampling for paged/lo spaces

src/profiler/sampling-heap-profiler.h

 // Copyright 2015 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.
 
 #ifndef V8_PROFILER_SAMPLING_HEAP_PROFILER_H_
 #define V8_PROFILER_SAMPLING_HEAP_PROFILER_H_
 
 #include <deque>
 #include <map>
 #include <set>
 #include "include/v8-profiler.h"
 #include "src/heap/heap.h"
 #include "src/profiler/strings-storage.h"
 
 namespace v8 {
 
 namespace base {
 class RandomNumberGenerator;
 }
 
 namespace internal {
 
+class SamplingAllocationObserver;
 
 class AllocationProfile : public v8::AllocationProfile {
  public:
   AllocationProfile() : nodes_() {}
 
   Node* GetRootNode() override {
     return nodes_.size() == 0 ? nullptr : &nodes_.front();
   }
 
   std::deque<Node>& nodes() { return nodes_; }
 
  private:
   std::deque<Node> nodes_;
 
   DISALLOW_COPY_AND_ASSIGN(AllocationProfile);
 };
 
-class SamplingHeapProfiler : public InlineAllocationObserver {
+
+class SamplingHeapProfiler {
  public:
   SamplingHeapProfiler(Heap* heap, StringsStorage* names, uint64_t rate,
                        int stack_depth);
   ~SamplingHeapProfiler();
 
   v8::AllocationProfile* GetAllocationProfile();
 
-  void Step(int bytes_allocated, Address soon_object, size_t size) override;
-  intptr_t GetNextStepSize() override {
-    return GetNextSampleInterval(random_, rate_);
-  }
-
   StringsStorage* names() const { return names_; }
 
   class FunctionInfo {
    public:
     FunctionInfo(SharedFunctionInfo* shared, StringsStorage* names);
     explicit FunctionInfo(const char* name)
         : name_(name),
           script_name_(""),
           script_id_(v8::UnboundScript::kNoScriptId),
           start_position_(0) {}
@@ skipping 29 matching lines @@
 
     SamplingHeapProfiler* const sampling_heap_profiler_;
     Global<Value> global_;
     std::vector<FunctionInfo*> stack_;
     const size_t size_;
 
     DISALLOW_COPY_AND_ASSIGN(SampledAllocation);
   };
 
  private:
+  friend class SamplingAllocationObserver;
   using Node = v8::AllocationProfile::Node;
 
   Heap* heap() const { return heap_; }
 
   void SampleObject(Address soon_object, size_t size);
 
-  static intptr_t GetNextSampleInterval(base::RandomNumberGenerator* random,
-                                        uint64_t rate);
-
   // Methods that construct v8::AllocationProfile.
   Node* AddStack(AllocationProfile* profile,
                  const std::map<int, Script*>& scripts,
                  const std::vector<FunctionInfo*>& stack);
   Node* FindOrAddChildNode(AllocationProfile* profile,
                            const std::map<int, Script*>& scripts, Node* parent,
                            FunctionInfo* function_info);
   Node* AllocateNode(AllocationProfile* profile,
                      const std::map<int, Script*>& scripts,
                      FunctionInfo* function_info);
 
   Isolate* const isolate_;
   Heap* const heap_;
-  base::RandomNumberGenerator* const random_;
+  SamplingAllocationObserver* new_space_observer_;
+  SamplingAllocationObserver* other_spaces_observer_;
   StringsStorage* const names_;
   std::set<SampledAllocation*> samples_;
-  const uint64_t rate_;
   const int stack_depth_;
 };
 
 
+class SamplingAllocationObserver : public AllocationObserver {
+ public:
+  explicit SamplingAllocationObserver(Heap* heap, intptr_t step_size,
+                                      uint64_t rate,
+                                      SamplingHeapProfiler* profiler,
+                                      base::RandomNumberGenerator* random)
+      : AllocationObserver(heap, step_size),
+        profiler_(profiler),
+        rate_(rate),
+        random_(random) {}
+  virtual ~SamplingAllocationObserver() {}
+
+ protected:
+  void Step(int bytes_allocated, Address soon_object, size_t size) override {
+    DCHECK(heap_->gc_state() == Heap::NOT_IN_GC);
+    DCHECK(soon_object);
+    profiler_->SampleObject(soon_object, size);
+  }
+
+  intptr_t GetNextStepSize() override {
+    return GetNextSampleInterval(random_, rate_);
+  }
+
+ private:
+  SamplingHeapProfiler* profiler_;
+  uint64_t rate_;

[ofrobots, 2016/01/23 16:16:31]

Weak suggestion: prefer to group member together by type (e.g. pointers first).
This minimizes spurious padding inserted for alignment.

[mattloring, 2016/01/26 00:42:48]

Done.

+  base::RandomNumberGenerator* random_;

[ofrobots, 2016/01/23 16:16:31]

Mark the above as const. E.g. SamplingHeapProfiler* const profiler_;

[mattloring, 2016/01/26 00:42:48]

Done.

+
+  intptr_t GetNextSampleInterval(base::RandomNumberGenerator* random,
+                                 uint64_t rate);

[ofrobots, 2016/01/23 16:16:31]

Any reason you make this non-static here?

[mattloring, 2016/01/26 00:42:48]

I was having problems with `incomplete type base::RandomNumberGenerator` when
defining this function here. Is there another way around this?

[ofrobots, 2016/01/26 15:47:15]

Move (keep) the function in the .cc file. This can be a static function as this
doesn't refer to `this`.

+};
+
+
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_PROFILER_SAMPLING_HEAP_PROFILER_H_