[jdk17u-dev] RFR: 8305425: Thread.isAlive0 doesn't need to call into the VM

[Paul Hohensee]

On Tue, 13 Jun 2023 09:02:28 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> Unclean backport to improve `Thread.isAlive` performance, and provide grounds for more backports in the area.
> 
> The majority of conflicts are due to integration of Loom in JDK 19, which reshaped some Thread code. I tried to change as little in 17u as possible to avoid the change fan-out.
> 
> Additional testing:
>  - [x] Linux x86_64 fastdebug `tier1 tier2 tier3`
>  - [x] Linux AArch64 fastdebug `tier1 tier2 tier3`

Lgtm.

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Marked as reviewed by phh (Reviewer).

PR Review: https://git.openjdk.org/jdk17u-dev/pull/1425#pullrequestreview-1478018350