For torch::from_blob() add clue when memory is non-owned. (#31222)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/31222
- When constructing torch::from_blob() in the case where the deleter is a nop, switch to using a nullptr context in the DataPtr (with a nop deleter)
- No real extra memory/cpu requirements here, actually saves a minor alloc.
Why? Trying to get a signal that a Tensor might contain non-owned memory from
torch::from_blob(), by detecting the nullptr context.
ghstack-source-id: 96336078
Test Plan:
buck test mode/dev caffe2/test/cpp/api/...
buck test mode/dev-nosan caffe2/test/...
Differential Revision: D18992119
fbshipit-source-id: 4eea642f82d0858b57fdfc6995364a760c10567d
