[jdk21u-dev] Integrated: 8320707: Virtual thread test updates

[Aleksey Shipilev]

On Tue, 5 Mar 2024 12:29:13 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> Test-only backport that simplifies Loom maintenance. The original commit applies cleanly, but it does not work out of the box, because `VThreadPinner` uses FFM, which is a preview feature in JDK 21, made final in JDK 22. My attempts to soft-touch FFM into working in JDK 21 with these tests failed: x86_32's fallback linker does not work properly in JDK 21, so tests cannot complete there.
> 
> Therefore, I made a side-ways move here: rewrote `VThreadPinner` to use `synchronized`, which still pins the thread in JDK 21, and would likely continue doing so. It is unlikely we would backport the runtime changes required to avoid pinning on synchronized blocks. This is what the old tests did anyway.
> 
> This would also make subsequent backports clean.
> 
> Additional testing:
>  - [x] MacOS AArch64 server fastdebug, `jdk_loom hotspot_loom`

This pull request has now been integrated.

Changeset: 41237fce
Author:    Aleksey Shipilev <shade at openjdk.org>
URL:       https://git.openjdk.org/jdk21u-dev/commit/41237fce959471f9274cd122108b7c3bc2c3042d
Stats:     894 lines in 15 files changed: 531 ins; 213 del; 150 mod

8320707: Virtual thread test updates

Reviewed-by: simonis
Backport-of: b67b71cd87c62f15d5b73f923c300d0f77c988f5

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PR: https://git.openjdk.org/jdk21u-dev/pull/328