Update unsloth for torch.cuda.amp deprecation (#2042)

* update deprecated unsloth tirch cuda amp  decorator

* WIP fix torch.cuda.amp deprecation

* lint

* laxing torch version requirement

* remove use of partial

* remove use of partial

* lint

---------

Co-authored-by: sunny <sunnyliu19981005@gmail.com>

src/axolotl/utils/gradient_checkpointing/unsloth.py

@@ -14,6 +14,16 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import torch
+from packaging import version
+
+torch_version = version.parse(torch.__version__)
+
+if torch_version < version.parse("2.4.0"):
+    torch_cuda_amp_custom_fwd = torch.cuda.amp.custom_fwd
+    torch_cuda_amp_custom_bwd = torch.cuda.amp.custom_bwd
+else:
+    torch_cuda_amp_custom_fwd = torch.amp.custom_fwd(device_type="cuda")
+    torch_cuda_amp_custom_bwd = torch.amp.custom_bwd(device_type="cuda")
 
 
 class Unsloth_Offloaded_Gradient_Checkpointer(  # pylint: disable=invalid-name
@@ -25,7 +35,7 @@ class Unsloth_Offloaded_Gradient_Checkpointer(  # pylint: disable=invalid-name
     """
 
     @staticmethod
-    @torch.cuda.amp.custom_fwd
+    @torch_cuda_amp_custom_fwd
     def forward(ctx, forward_function, hidden_states, *args):
         saved_hidden_states = hidden_states.to("cpu", non_blocking=True)
         with torch.no_grad():
@@ -36,7 +46,7 @@ def forward(ctx, forward_function, hidden_states, *args):
         return output
 
     @staticmethod
-    @torch.cuda.amp.custom_bwd
+    @torch_cuda_amp_custom_bwd
     def backward(ctx, dY):
         (hidden_states,) = ctx.saved_tensors
         hidden_states = hidden_states.to("cuda", non_blocking=True).detach()