Share blit queue for device-to-device and device-to-host copies

Reduces the number of blit queues from 3 to 2, when SDMA is unavailable,
improving the availability of queue slots for applications.

Change-Id: I8860d2b6c6d6527494b9fc35d164099e1313886a

runtime/hsa-runtime/core/runtime/amd_gpu_agent.cpp

@@ -133,14 +133,6 @@ GpuAgent::GpuAgent(HSAuint32 node, const HsaNodeProperties& node_props)
 }
 
 GpuAgent::~GpuAgent() {
-  if (blit_d2d_ != NULL) {
-    hsa_status_t status = blit_d2d_->Destroy(*this);
-    assert(status == HSA_STATUS_SUCCESS);
-
-    delete blit_d2d_;
-    blit_d2d_ = NULL;
-  }
-
   if (blit_h2d_ != NULL) {
     hsa_status_t status = blit_h2d_->Destroy(*this);
     assert(status == HSA_STATUS_SUCCESS);
@@ -149,7 +141,7 @@ GpuAgent::~GpuAgent() {
     blit_h2d_ = NULL;
   }
 
-  if (blit_d2h_ != NULL) {
+  if (blit_d2h_ != NULL && blit_d2h_ != blit_d2d_) {
     hsa_status_t status = blit_d2h_->Destroy(*this);
     assert(status == HSA_STATUS_SUCCESS);
 
@@ -157,6 +149,14 @@ GpuAgent::~GpuAgent() {
     blit_d2h_ = NULL;
   }
 
+  if (blit_d2d_ != NULL) {
+    hsa_status_t status = blit_d2d_->Destroy(*this);
+    assert(status == HSA_STATUS_SUCCESS);
+
+    delete blit_d2d_;
+    blit_d2d_ = NULL;
+  }
+
   if (end_ts_base_addr_ != NULL) {
     core::Runtime::runtime_singleton_->FreeMemory(end_ts_base_addr_);
   }
@@ -547,7 +547,8 @@ void GpuAgent::InitDma() {
       }
 
       if (blit_d2h_ == NULL) {
-        blit_d2h_ = CreateBlitKernel();
+        // Share device-to-host queue with device-to-device.
+        blit_d2h_ = blit_d2d_;
       }
 
       blit_initialized_.store(true, std::memory_order_release);