RFR: 8325469: Freeze/Thaw code can crash in the presence of OSR frames [v3]

[Vladimir Kozlov]

On Wed, 17 Apr 2024 16:17:39 GMT, Patricio Chilano Mateo <pchilanomate at openjdk.org> wrote:

>> It may be hard to do a proper measurement because the number of methods in our microbenchmarks is small. We're also talking an extra branch, I think. This is code than can be called a million times per second per core. It's very performance sensitive. So I would prefer to first see if there's an impact on nmethod size, and only if there is consider whether the speed implications are acceptable.
>
> Thanks for the reviews @pron and @dean-long!

Hi @pchilano
 
 This change did affect my PR which try to reduce `nmethod` header size [#18768](https://github.com/openjdk/jdk/pull/18768).

I am fine with caching the value in `nmethod` but why you used `int` field for it? It is `u2` in [constMethod.hpp#L209](https://github.com/openjdk/jdk/blob/master/src/hotspot/share/oops/constMethod.hpp#L209).

I am currently resolving conflict in my PR with your changes and I am planning to use `u2` for it in `nmethod` too. Are you okay with that?

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PR Comment: https://git.openjdk.org/jdk/pull/18637#issuecomment-2062147495