Simplify OpKernel (#17925)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/17925
There's no need for OpKernel to keep the cache creator around if we initialize cache on construction.
This basically means, kernel caches are now constructed when the kernel is looked up from the dispatcher, and not delayed to the first call anymore.
This gives us the benefit of cheaper calling because now kernel calling doesn't have to check if the cache is already initialized.
Also, this improves thread-safety. Now, OpKernel is thread-safe if the kernel is thread-safe.
Reviewed By: ezyang
Differential Revision: D14424907
fbshipit-source-id: a0d09a3a560dfe78aab53d558c9ebb91b57722df
