RFR: 8358821: patch_verified_entry causes problems, use nmethod entry barriers instead [v9]

[Dean Long]

On Tue, 24 Jun 2025 16:13:26 GMT, Dean Long <dlong at openjdk.org> wrote:

>> Just FYI: My local tier1-3 test on linux-riscv64 is good. And I didn't witness an obvious change on specjbb performance with g1gc.
>
> Thanks @RealFYang.

> @dean-long: Are you planning to do a jdk25 backport? We still see the crashes, there.

I was going to let it bake in jdk26 for a while before deciding.  It seems a bit risky to me.  I am leaning towards not backporting it to Oracle JDK.  For OpenJDK 25, it might make more sense to do a PPC-specific fix like adding a NOP at the verified entry point.  What do you think?

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PR Comment: https://git.openjdk.org/jdk/pull/25764#issuecomment-3014307981