Fix shared_ptr refcycle in graph executor #10222
Closed
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Fixes pytorch#10032 When capturing an output, GraphExecutorAutogradFunction creates SavedVariable with is_output=False and owns it: https://github.com/pytorch/pytorch/blob/master/torch/csrc/jit/graph_executor.cpp#L87 Constructing SavedVariable with is_output=False makes it own a copy of the shared_ptr<GraphExecutorAutogradFunction>, which causes a reference cycle: https://github.com/pytorch/pytorch/blob/6456b944fd3dfe1b7db830b27afd44b15ba5a6e9/torch/csrc/autograd/saved_variable.cpp#L27 The solution in this PR is to construct the SavedVariable with is_output=True if the captured value is an output. Test Plan Turn on cuda memory checking for JitTestCase. If the test's name includes "cuda" or "gpu" in it, the cuda memory checking test happens.
zou3519
requested review from
apaszke,
colesbury,
ezyang,
gchanan,
soumith and
zdevito
as code owners
soumith
approved these changes
Aug 3, 2018
There was a problem hiding this comment.
zou3519 has imported this pull request. If you are a Facebook employee, you can view this diff on Phabricator.
zdevito
approved these changes
Aug 4, 2018
goodlux
pushed a commit
to goodlux/pytorch
that referenced
this pull request
Aug 15, 2018
Summary: Fixes pytorch#10032 When capturing an output, GraphExecutorAutogradFunction creates SavedVariable with is_output=False and owns it: https://github.com/pytorch/pytorch/blob/master/torch/csrc/jit/graph_executor.cpp#L87 Constructing SavedVariable with is_output=False makes it own a copy of the shared_ptr<GraphExecutorAutogradFunction>, which causes a reference cycle: https://github.com/pytorch/pytorch/blob/6456b944fd3dfe1b7db830b27afd44b15ba5a6e9/torch/csrc/autograd/saved_variable.cpp#L27 The solution in this PR is to construct the SavedVariable with is_output=True if the captured value is an output. Test Plan Turn on cuda memory checking for JitTestCase. If the test's name includes "cuda" or "gpu" in it, the cuda memory checking test happens. cc zdevito Pull Request resolved: pytorch#10222 Reviewed By: ezyang Differential Revision: D9162995 Pulled By: zou3519 fbshipit-source-id: aeace85a09160c7a7e79cf35f6ac61eac87cbf66
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Fixes #10032
When capturing an output, GraphExecutorAutogradFunction creates
SavedVariable with is_output=False and owns it:
https://github.com/pytorch/pytorch/blob/master/torch/csrc/jit/graph_executor.cpp#L87
Constructing SavedVariable with is_output=False makes it own a copy of
the shared_ptr, which causes a reference
cycle:
pytorch/torch/csrc/autograd/saved_variable.cpp
Line 27 in 6456b94
The solution in this PR is to construct the SavedVariable with
is_output=True if the captured value is an output.
Test Plan
Turn on cuda memory checking for JitTestCase. If the test's name
includes "cuda" or "gpu" in it, the cuda memory checking test happens.
cc @zdevito