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x/sync: semaphore.Weighted.Acquire should try to notify other waiters when canceled #37852

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zhiqiangxu opened this issue Mar 14, 2020 · 1 comment
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x/sync: semaphore.Weighted.Acquire should try to notify other waiters when canceled #37852

zhiqiangxu opened this issue Mar 14, 2020 · 1 comment
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FrozenDueToAge NeedsFix The path to resolution is known, but the work has not been done.
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@zhiqiangxu
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zhiqiangxu commented Mar 14, 2020 •
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When Release, if the remaining tokens are not enough for the front waiter, no waiters will be notified.

So if the canceled waiter is the front one, it should try to notify following waiters if there are remaining tokens.

I found this bug when implementing a cancelable rwmutex based on semaphore:

https://github.com/zhiqiangxu/util/blob/master/mutex/crwmutex.go

This bug can be verified by this test:

https://github.com/zhiqiangxu/util/blob/master/mutex/crwmutex_test.go#L43

I've submitted a PR here: golang/sync#10
@gopherbot gopherbot added this to the Unreleased milestone Mar 14, 2020
@zhiqiangxu zhiqiangxu changed the title x/sync: semaphore.Weighted.Acquire should try to notify other waiters x/sync: semaphore.Weighted.Acquire should try to notify other waiters when canceled Mar 14, 2020
@cagedmantis cagedmantis added the NeedsFix The path to resolution is known, but the work has not been done. label Mar 20, 2020
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This has been fixed via: https://go-review.googlesource.com/c/sync/+/223418

@golang golang locked and limited conversation to collaborators Mar 20, 2021
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