RFR: 8263476: Use reserved memory for stack guard pages [v3]

[Albert Mingkun Yang]

On Fri, 8 Aug 2025 16:54:31 GMT, Zhengyu Gu <zgu at openjdk.org> wrote:

> I believe I wanted to get rid of this commit_memory call which has the undesirable side-effort to NMT.

Yes, I believe I understand that correctly and achieved that in this PR.

> BTW, do you need the reserve_memory(), are the guard pages already reserved as part of stack?

It's platform-specific. For linux, only `is_primordial_thread` reserves stack-memory dynamically, so we need to do sth special for it. Other threads have all stack-memory reserved, requires no preparation before calling `os::guard_memory`. (I covered this in the implementation note section of ticket description, just fyi.)

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

PR Review Comment: https://git.openjdk.org/jdk/pull/26571#discussion_r2263804282