Remove a few TODOs in stream_executor.cc.

1. I am thinking if `void* ext` is not really needed in DeviceMemoryBase. Additional data can probably be stored in the `void* opaque` handle.
2. AllocatorStats already appear to be validated.

PiperOrigin-RevId: 344154575
Change-Id: I6cac6aa60979a0ee9116b586b9b16894fd57be7e

tensorflow/c/experimental/stream_executor/stream_executor.cc

@@ -321,14 +321,12 @@ SP_DeviceMemoryBase DeviceMemoryBaseToC(const DeviceMemoryBase* mem) {
   device_memory_base.opaque = const_cast<void*>(mem->opaque());
   device_memory_base.size = mem->size();
   device_memory_base.payload = mem->payload();
-  // TODO(annarev): Add `ext` field to DeviceMemoryBase and set it here.
   return device_memory_base;
 }
 
 DeviceMemoryBase DeviceMemoryBaseFromC(const SP_DeviceMemoryBase& mem) {
   DeviceMemoryBase base(mem.opaque, mem.size);
   base.SetPayload(mem.payload);
-  // TODO(annarev): Add `ext` field to DeviceMemoryBase and set it here.
   return base;
 }
 
@@ -426,7 +424,6 @@ class CStreamExecutor : public internal::StreamExecutorInterface {
       LOG(ERROR) << status.error_message();
       return absl::nullopt;
     }
-    // TODO(annarev): validate SP_AllocatorStats.
     ::stream_executor::AllocatorStats stats;
     stats.num_allocs = c_stats.num_allocs;
     stats.bytes_in_use = c_stats.bytes_in_use;

tensorflow/c/experimental/stream_executor/stream_executor.h

@@ -140,8 +140,9 @@ typedef enum SE_EventStatus {
 // https://cs.opensource.google/tensorflow/tensorflow/+/refs/tags/v2.3.0:tensorflow/stream_executor/device_memory.h;l=57
 typedef struct SP_DeviceMemoryBase {
   size_t struct_size;
-  void* ext;  // free-form data set by plugin
+  void* ext;  // Reserved for future use
   // Platform-dependent value representing allocated memory.
+  // Note that the pointer does not have to be to the virtual address itself.
   void* opaque;
   uint64_t size;     // Size in bytes of this allocation.
   uint64_t payload;  // Value for plugin's use