RFR: 8376650: os::release_memory_special may not be needed anymore

[Stefan Johansson]

On Mon, 23 Feb 2026 13:47:34 GMT, Casper Norrbin <cnorrbin at openjdk.org> wrote:

> Hi everyone,
> 
> `os::release_memory_special` releases memory backed by explicit (non-THP) large pages on Linux. Its point was to handle the case where explicit large pages were allocated with system V shared memory instead of mmap. Since we removed the use of system V memory with [JDK-8261894](https://bugs.openjdk.org/browse/JDK-8261894), `pd_release_memory_special` was changed to simply forward to `pd_release_memory`. 
> 
> With these functions no longer serving a purpose (`os::release_memory_special` effectively just calls `os::release_memory`) I propose we remove them completely and replace uses with calls to `os::release_memory` instead.
> 
> Testing:
> - Oracle tiers 1-5

Looks good, thanks for handling this.

-------------

Marked as reviewed by sjohanss (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/29880#pullrequestreview-3846173952