RFR: 8229147: Linux os::create_thread() overcounts guardpage size with newer glibc (>=2.27)

[Thomas Stuefe]

On Fri, 21 Apr 2023 04:57:28 GMT, David Holmes <dholmes at openjdk.org> wrote:

> We can now detect whether glibc includes the guard pages as part of the requested stack size or not, and so only need to make adjustments when glibc requires it.
> 
> The intent was to use a local variable as the "flag" but unfortunately it is also needed in os_posix.cpp so I had to make it part of the os::Linux API.
> 
> See bug report (and related) for details.
> 
> Testing:
>   - Manually checked log output for stack sizes and boundaries on systems with and without the glibc fix. (Again see JBS issue)
>   -  Tiers 1-3 sanity
> Thanks

I'll approve, patch looks like it would work and you seem to want to get it off your table quickly. I don't want to keep this up - any cleanups can be done in separate RFEs, if you prefer.

Cheers, Thomas

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Marked as reviewed by stuefe (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/13571#pullrequestreview-1397480277