pytorch

168c0797 - Remind users to set map_location properly when using DDP

Remind users to set map_location properly when using DDP Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/19084 Differential Revision: D14861702 Pulled By: mrshenli fbshipit-source-id: 10ca4a9b41e707050a6bce228ccca4177c9fa4a6