[Offload] Remove non-blocking allocation type

Summary:
This was originally added in as a hack to work around CUDA's limitation
on allocation. The `libc` implementation now isn't even used for CUDA so
this code is never hit. Even if this case, this code never truly worked.

A true solution would be to use CUDA's virtual memory API instead to
allocate 2MiB slabs independenctly from the normal memory management
done in the stream.

Author: jhuber6

offload/include/omptarget.h

@@ -101,8 +101,6 @@ enum TargetAllocTy : int32_t {
   TARGET_ALLOC_HOST,
   TARGET_ALLOC_SHARED,
   TARGET_ALLOC_DEFAULT,
-  /// The allocation will not block on other streams.
-  TARGET_ALLOC_DEVICE_NON_BLOCKING,
 };
 
 inline KernelArgsTy CTorDTorKernelArgs = {

offload/plugins-nextgen/amdgpu/src/rtl.cpp

@@ -2350,7 +2350,6 @@ struct AMDGPUDeviceTy : public GenericDeviceTy, AMDGenericDeviceTy {
     switch (Kind) {
     case TARGET_ALLOC_DEFAULT:
     case TARGET_ALLOC_DEVICE:
-    case TARGET_ALLOC_DEVICE_NON_BLOCKING:
       MemoryPool = CoarseGrainedMemoryPools[0];
       break;
     case TARGET_ALLOC_HOST:
@@ -3847,7 +3846,6 @@ void *AMDGPUDeviceTy::allocate(size_t Size, void *, TargetAllocTy Kind) {
   switch (Kind) {
   case TARGET_ALLOC_DEFAULT:
   case TARGET_ALLOC_DEVICE:
-  case TARGET_ALLOC_DEVICE_NON_BLOCKING:
     MemoryPool = CoarseGrainedMemoryPools[0];
     break;
   case TARGET_ALLOC_HOST:

offload/plugins-nextgen/common/include/ErrorReporting.h

@@ -61,7 +61,6 @@ class ErrorReporter {
   /// Return a nice name for an TargetAllocTy.
   static StringRef getAllocTyName(TargetAllocTy Kind) {
     switch (Kind) {
-    case TARGET_ALLOC_DEVICE_NON_BLOCKING:
     case TARGET_ALLOC_DEFAULT:
     case TARGET_ALLOC_DEVICE:
       return "device memory";

offload/plugins-nextgen/common/src/PluginInterface.cpp

@@ -1295,7 +1295,6 @@ Expected<void *> GenericDeviceTy::dataAlloc(int64_t Size, void *HostPtr,
 
   switch (Kind) {
   case TARGET_ALLOC_DEFAULT:
-  case TARGET_ALLOC_DEVICE_NON_BLOCKING:
   case TARGET_ALLOC_DEVICE:
     if (MemoryManager) {
       Alloc = MemoryManager->allocate(Size, HostPtr);
@@ -1386,7 +1385,6 @@ Error GenericDeviceTy::dataDelete(void *TgtPtr, TargetAllocTy Kind) {
   int Res;
   switch (Kind) {
   case TARGET_ALLOC_DEFAULT:
-  case TARGET_ALLOC_DEVICE_NON_BLOCKING:
   case TARGET_ALLOC_DEVICE:
     if (MemoryManager) {
       Res = MemoryManager->free(TgtPtr);

offload/plugins-nextgen/common/src/RPC.cpp

@@ -28,15 +28,15 @@ rpc::Status handleOffloadOpcodes(plugin::GenericDeviceTy &Device,
   switch (Port.get_opcode()) {
   case LIBC_MALLOC: {
     Port.recv_and_send([&](rpc::Buffer *Buffer, uint32_t) {
-      Buffer->data[0] = reinterpret_cast<uintptr_t>(Device.allocate(
-          Buffer->data[0], nullptr, TARGET_ALLOC_DEVICE_NON_BLOCKING));
+      Buffer->data[0] = reinterpret_cast<uintptr_t>(
+          Device.allocate(Buffer->data[0], nullptr, TARGET_ALLOC_DEVICE));
     });
     break;
   }
   case LIBC_FREE: {
     Port.recv([&](rpc::Buffer *Buffer, uint32_t) {
       Device.free(reinterpret_cast<void *>(Buffer->data[0]),
-                  TARGET_ALLOC_DEVICE_NON_BLOCKING);
+                  TARGET_ALLOC_DEVICE);
     });
     break;
   }

offload/plugins-nextgen/cuda/src/rtl.cpp

@@ -587,16 +587,6 @@ struct CUDADeviceTy : public GenericDeviceTy {
       Res = cuMemAllocManaged(&DevicePtr, Size, CU_MEM_ATTACH_GLOBAL);
       MemAlloc = (void *)DevicePtr;
       break;
-    case TARGET_ALLOC_DEVICE_NON_BLOCKING: {
-      CUstream Stream;
-      if ((Res = cuStreamCreate(&Stream, CU_STREAM_NON_BLOCKING)))
-        break;
-      if ((Res = cuMemAllocAsync(&DevicePtr, Size, Stream)))
-        break;
-      cuStreamSynchronize(Stream);
-      Res = cuStreamDestroy(Stream);
-      MemAlloc = (void *)DevicePtr;
-    }
     }
 
     if (auto Err =
@@ -627,15 +617,6 @@ struct CUDADeviceTy : public GenericDeviceTy {
     case TARGET_ALLOC_HOST:
       Res = cuMemFreeHost(TgtPtr);
       break;
-    case TARGET_ALLOC_DEVICE_NON_BLOCKING: {
-      CUstream Stream;
-      if ((Res = cuStreamCreate(&Stream, CU_STREAM_NON_BLOCKING)))
-        break;
-      cuMemFreeAsync(reinterpret_cast<CUdeviceptr>(TgtPtr), Stream);
-      cuStreamSynchronize(Stream);
-      if ((Res = cuStreamDestroy(Stream)))
-        break;
-    }
     }
 
     if (auto Err = Plugin::check(Res, "error in cuMemFree[Host]: %s")) {

offload/plugins-nextgen/host/src/rtl.cpp

@@ -250,7 +250,6 @@ struct GenELF64DeviceTy : public GenericDeviceTy {
     case TARGET_ALLOC_DEVICE:
     case TARGET_ALLOC_HOST:
     case TARGET_ALLOC_SHARED:
-    case TARGET_ALLOC_DEVICE_NON_BLOCKING:
       MemAlloc = std::malloc(Size);
       break;
     }