RFR: 8324781: runtime/Thread/TestAlwaysPreTouchStacks.java failed with Expected a higher ratio between stack committed and reserved [v5]

[Stefan Karlsson]

On Tue, 9 Apr 2024 08:43:42 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:
> 
>   Mis-removed the two lines

Changes requested by stefank (Reviewer).

src/hotspot/os/linux/os_linux.cpp line 4843:

> 4841:       (ret == 0 &&
> 4842:        (sscanf(buffer.release, "%ld.%ld", &major, &minor) == 2) &&
> 4843:        (major > 5 || (major == 5 && minor >= 14)) &&

Why isn't this using the `os::Linux::kernel_version()` function?

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PR Review: https://git.openjdk.org/jdk/pull/18592#pullrequestreview-1988904307
PR Review Comment: https://git.openjdk.org/jdk/pull/18592#discussion_r1557547678