RFR: 8324781: runtime/Thread/TestAlwaysPreTouchStacks.java failed with Expected a higher ratio between stack committed and reserved [v6]

[David Holmes]

On Wed, 10 Apr 2024 06:28:36 GMT, Liming Liu <duke at openjdk.org> wrote:

>> The testcase failed on Oracle CI since JDK-8315923. The root cause is that Oracle CI runs Linux-5.4.17-UEK where the value of MADV_POPULATE_WRITE (23) is used as MADV_DONTEXEC which is not supported by upstream. This PR solves the testcase failure by checking versions of kernels first, and checking the availability of MADV_POPULATE_WRITE when they are not older than 5.14.
>
> Liming Liu has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Use kernel_version

src/hotspot/os/linux/os_linux.cpp line 4836:

> 4834:     bool supportMadvPopulateWrite =
> 4835:       ((major > 5 || (major == 5 && minor >= 14)) &&
> 4836:        (::madvise(0, 0, MADV_POPULATE_WRITE) == 0));

Shouldn't this be checking ` MADV_POPULATE_WRITE_value `?

I still can't get my head around the possible compile time values versus the potential runtime interpretation of the ` MADV_POPULATE_WRITE`  value.

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PR Review Comment: https://git.openjdk.org/jdk/pull/18592#discussion_r1567039839