Change default `max_shard_size` to smaller value (#26942)

* Update modeling_utils.py

* fixup

* let's change it to 5GB

* fix

src/transformers/modeling_utils.py

@@ -1867,7 +1867,7 @@ class PreTrainedModel(nn.Module, ModuleUtilsMixin, GenerationMixin, PushToHubMix
         state_dict: Optional[dict] = None,
         save_function: Callable = torch.save,
         push_to_hub: bool = False,
-        max_shard_size: Union[int, str] = "10GB",
+        max_shard_size: Union[int, str] = "5GB",
         safe_serialization: bool = False,
         variant: Optional[str] = None,
         token: Optional[Union[str, bool]] = None,
@@ -1896,9 +1896,11 @@ class PreTrainedModel(nn.Module, ModuleUtilsMixin, GenerationMixin, PushToHubMix
                 Whether or not to push your model to the Hugging Face model hub after saving it. You can specify the
                 repository you want to push to with `repo_id` (will default to the name of `save_directory` in your
                 namespace).
-            max_shard_size (`int` or `str`, *optional*, defaults to `"10GB"`):
+            max_shard_size (`int` or `str`, *optional*, defaults to `"5GB"`):
                 The maximum size for a checkpoint before being sharded. Checkpoints shard will then be each of size
                 lower than this size. If expressed as a string, needs to be digits followed by a unit (like `"5MB"`).
+                We default it to 5GB in order for models to be able to run easily on free-tier google colab instances
+                without CPU OOM issues.
 
                 <Tip warning={true}>
 

src/transformers/utils/hub.py

@@ -790,7 +790,7 @@ class PushToHubMixin:
         commit_message: Optional[str] = None,
         private: Optional[bool] = None,
         token: Optional[Union[bool, str]] = None,
-        max_shard_size: Optional[Union[int, str]] = "10GB",
+        max_shard_size: Optional[Union[int, str]] = "5GB",
         create_pr: bool = False,
         safe_serialization: bool = False,
         revision: str = None,
@@ -814,10 +814,11 @@ class PushToHubMixin:
                 The token to use as HTTP bearer authorization for remote files. If `True`, will use the token generated
                 when running `huggingface-cli login` (stored in `~/.huggingface`). Will default to `True` if `repo_url`
                 is not specified.
-            max_shard_size (`int` or `str`, *optional*, defaults to `"10GB"`):
+            max_shard_size (`int` or `str`, *optional*, defaults to `"5GB"`):
                 Only applicable for models. The maximum size for a checkpoint before being sharded. Checkpoints shard
                 will then be each of size lower than this size. If expressed as a string, needs to be digits followed
-                by a unit (like `"5MB"`).
+                by a unit (like `"5MB"`). We default it to `"5GB"` so that users can easily load models on free-tier
+                Google Colab instances without any CPU OOM issues.
             create_pr (`bool`, *optional*, defaults to `False`):
                 Whether or not to create a PR with the uploaded files or directly commit.
             safe_serialization (`bool`, *optional*, defaults to `False`):