RFR: JDK-8312394: [linux] SIGSEGV if kernel was built without hugepage support

[Aleksey Shipilev]

On Wed, 19 Jul 2023 14:11:28 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

> Somewhat trivial fixes. Hugepage detection crashes on systems whose kernels have no support compiled in for them.
> 
> - check the result of opendir() before using
> - don't scan for hugepages at all if we don't have a default hugepage.

Looks reasonable.

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Marked as reviewed by shade (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/14936#pullrequestreview-1538894814