torch.utils.checkpoint warns if user does not pass use_reentrant explicitly (#100551)
Now that we have updated all internal callsites, per https://fb.workplace.com/groups/pytorch.oss.dev/permalink/1635183750239493/ we should raise a warning when use_reentrant is not explicitly passed for 2.1
Deprecation note:
- Not passing in use_reentrant explicitly is now deprecated and will raise a warning. In the future the default value of use-reentrant will be False. To preserve the existing behavior you can pass in use_reentrant=True. It is recommended that you use use_reentrant=False.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/100551
Approved by: https://github.com/Skylion007
