[Fix] fix data race risk of cache_randomness
#2927
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added 2 commits
September 7, 2023 13:52
ly015
reviewed
Sep 7, 2023
mmcv/transforms/utils.py
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| @@ -80,7 +81,7 @@ def __call__(self, *args, **kwargs): | |||
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| def __get__(self, obj, cls): | |||
| self.instance_ref = weakref.ref(obj) | |||
| return self | |||
| return copy.deepcopy(self) | |||
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Suggested change
| return copy.deepcopy(self) | |
| return copy.copy(self) |
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Done. Thanks for your suggestion.
ly015
reviewed
Sep 7, 2023
ly015
reviewed
Sep 7, 2023
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Thanks for your contribution and we appreciate it a lot. The following instructions would make your pull request more healthy and more easily get feedback. If you do not understand some items, don't worry, just make the pull request and seek help from maintainers.
Motivation
Please describe the motivation of this PR and the goal you want to achieve through this PR.
fix the bug mentioned in #2926
Modification
Please briefly describe what modification is made in this PR.
The bug mentioned in #2926 is caused by the data race of multithreading. I do not think it is a good idea to use a pointer here to point to different instances. This can lead to disaster in concurrent situations. To keep modifications minimal, I implemented a version that creates a new copy every time "cache_randomness" is accessed to avoid data races of multithreading. Since this class "cache_randomness" only contains two pointers, one pointing to the class method (rather than the bound method) and the other to the class, the additional overhead brought here is subtle.
BC-breaking (Optional)
Does the modification introduce changes that break the backward-compatibility of the downstream repositories?
If so, please describe how it breaks the compatibility and how the downstream projects should modify their code to keep compatibility with this PR.
I do not think it breaks
Use cases (Optional)
If this PR introduces a new feature, it is better to list some use cases here, and update the documentation.
Checklist
Before PR:
After PR: