Fix pin_memory_thread not exiting quickly

[ssnl]

fixes #23642

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[ngimel]

Can we have a test timinig worker shutdown (similar to example in #23642), or do you think it will be too flaky?

[ssnl]

Yeah I thought about that but was worried it will be too flaky. Because the “slow” shutdown time is smaller than the multiprocessing communication timeout we allow on CI LOL.

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On Thu, Aug 1, 2019 at 12:23 ngimel ***@***.***> wrote: Can we have a test timinig worker shutdown (similar to example in #23642 <#23642>), or do you think it will be too flaky? — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#23646?email_source=notifications&email_token=ABLJMZMTLGHNT34FATCW3TLQCMEYFA5CNFSM4IINCEAKYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOD3LEM3I#issuecomment-517359213>, or mute the thread <https://github.com/notifications/unsubscribe-auth/ABLJMZLXZXW7TUFUSKAXACDQCMEYFANCNFSM4IINCEAA> .

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@soumith merged this pull request in 0539462.