RFR: 8314243: Make VM_Exit::wait_for_threads_in_native_to_block wait for user threads time configurable [v2]

[David Holmes]

On Tue, 14 Nov 2023 05:57:48 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> Jiangli Zhou has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Incorporate feedback/suggestion from David Holmes:
>>   - Change the flag to be expressed as the number of 10ms chunks (i.e. number of wait attempts) to wait.
>>   - Limit the max allowed wait to 10s. That's 1000 wait attempts with each attempt=10ms.
>
> src/hotspot/share/runtime/globals.hpp line 842:
> 
>> 840:           "JVM exit. Each wait attempt is 10-millisecond. The max allowed " \
>> 841:           "wait attempts for user threads in native is 1000, which is "     \
>> 842:           "10 seconds.")                                                    \
> 
> Suggestion:
> 
> The number of times to wait for user threads to stop executing native code
> during JVM exit. Each wait lasts 10 milliseconds. The maximum number of waits
> is 1000, to wait at most 10 seconds.

Also I just realized that it makes sense to limit the user thread attempts to the internal compiler thread maximum - otherwise we would still stop waiting once the compiler thread maximum was reached.

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PR Review Comment: https://git.openjdk.org/jdk/pull/16591#discussion_r1392024232