RFR: 8253926: Use extra_size correctly in anon_mmap_aligned

[Thomas Schatzl]

On Fri, 2 Oct 2020 10:00:27 GMT, Stefan Johansson <sjohanss at openjdk.org> wrote:

> A recent cleanup ([8253638: Cleanup os::reserve_memory and remove MAP_FIXED](https://github.com/openjdk/jdk/pull/357/))
> got a size mixed up in `anon_mmap_aligned()`. Instead of passing down the calculated `extra_size` to `anon_mmap()` it
> uses the original size `bytes`.  This resulted in an early crash when using large pages and with this fix the crash
> goes away.

Marked as reviewed by tschatzl (Reviewer).

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PR: https://git.openjdk.java.net/jdk/pull/479