Modify thread pool thread counting to be a bit more defensive #70478
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kouvel
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Jun 9, 2022
kouvel
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- An unexpected underflow in one or more thread counts can lead to a large number of threads to be created continually
- Prevented underflows in changes to thread counts, such that following an unexpected underflow, subsequent paired increments and decrements would avoid repeating the underflow
- Verified by creating an unexpected underflow in the debugger
- An unexpected underflow in one or more thread counts can lead to a large number of threads to be created continually - Prevented underflows in changes to thread counts, such that following an unexpected underflow, subsequent paired increments and decrements would avoid repeating the underflow - Verified by creating an unexpected underflow in the debugger
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kouvel
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Jun 9, 2022
- Port of dotnet#70478 to 6.0 - An unexpected underflow in one or more thread counts can lead to a large number of threads to be created continually - Prevented underflows in changes to thread counts, such that following an unexpected underflow, subsequent paired increments and decrements would avoid repeating the underflow - Verified by creating an unexpected underflow in the debugger
mangod9
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Jun 9, 2022
| set | ||
| { | ||
| Debug.Assert(value >= 0); | ||
| SetInt16Value(value, NumExistingThreadsShift); | ||
| SetInt16Value(Math.Max((short)0, value), NumExistingThreadsShift); |
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can this be changed to ushort to avoid the Math.Max in multiple places, or is that change going to be too disruptive?
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Changing to ushort wouldn't prevent an underflow, a check would still need to ensure that it does not cross zero and wrap around. It may have other undesirable effects in odd cases, probably not worth it.
mangod9
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Jun 9, 2022
src/libraries/System.Private.CoreLib/src/System/Threading/PortableThreadPool.WorkerThread.cs
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janvorli
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Jun 9, 2022
mangod9
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Jun 9, 2022
carlossanlop
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Jun 11, 2022
…70479) * [6.0] Modify thread pool thread counting to be a bit more defensive - Port of #70478 to 6.0 - An unexpected underflow in one or more thread counts can lead to a large number of threads to be created continually - Prevented underflows in changes to thread counts, such that following an unexpected underflow, subsequent paired increments and decrements would avoid repeating the underflow - Verified by creating an unexpected underflow in the debugger * Address feedback
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