message: Make MklCpuAllocator a VisitableAllocator, instead of just an Allocator.
  This allows it to work more efficiently with RDMA networking.
diff: @@ -46,7 +46,7 @@ class MklSubAllocator : public SubAllocator {
  /// CPU allocator for MKL that wraps BFC allocator and intercepts
  /// and redirects memory allocation calls from MKL.
  -class MklCPUAllocator : public Allocator {
  +class MklCPUAllocator : public VisitableAllocator {
  public:
  // Constructor and other standard functions
  @@ -119,6 +119,14 @@ class MklCPUAllocator : public Allocator {
  void ClearStats() override { allocator_->ClearStats(); }
  + void AddAllocVisitor(Visitor visitor) override {
  + allocator_->AddAllocVisitor(visitor);
  + }
  +
  + void AddFreeVisitor(Visitor visitor) override {
  + allocator_->AddFreeVisitor(visitor);
  + }
  +
  private:
  // Hooks provided by this allocator for memory allocation routines from MKL
  