RFR: 8284161: Implementation of Virtual Threads (Preview) [v11]

[Aleksey Shipilev]

On Wed, 4 May 2022 12:12:48 GMT, Alan Bateman <alanb at openjdk.org> wrote:

>> This is the implementation of JEP 425: Virtual Threads (Preview).
>> 
>> We will refresh this PR periodically to pick up changes and fixes from the loom repo.
>> 
>> Most of the new mechanisms in the HotSpot VM are disabled by default and require running with `--enable-preview` to enable.
>> 
>> The patch has support for x64 and aarch64 on the usual operating systems (Linux, macOS, and Windows). There are stubs (calling _Unimplemented_) for zero and some of the other ports. Additional ports can be contributed via PRs against the fibers branch in the loom repo.
>> 
>> There are changes in many areas. To reduce notifications/mails, the labels have been trimmed down for now to hotspot, serviceability and core-libs. We can add additional labels, if required, as the PR progresses.
>> 
>> The changes include a refresh of java.util.concurrent and ForkJoinPool from Doug Lea's CVS. These changes will probably be proposed and integrated in advance of this PR.
>> 
>> The changes include some non-exposed and low-level infrastructure to support the (in draft) JEPs for Structured Concurrency and Extent Locals. This is to make life a bit easier and avoid having to separate VM changes and juggle branches at this time.
>
> Alan Bateman has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 17 commits:
> 
>  - Refresh d77f7a49af75bcc5b20686805ff82a93a20dde05
>  - Merge with 4b2c82200fdc01de868cf414e40a4d891e753f89
>  - Refresh 6091080db743ece5f1b2111fcc35a5f2179a403a
>  - Merge with cfcba1fccc8e3e6a68e1cb1826b70e076d5d83c4
>  - Refresh ee9fa8ed05ec22de7a13383052d68aa8aa7832ec
>  - Merge with jdk-19+20
>  - Refresh 7965cc6b168e567ac2596f2fbc3b00a7d99b7e1e
>  - Refresh 8d8f0a2fd646e57fe6b4e8ab669f836dc46dda69
>  - Refresh cf561073f48fad58e931a5285b92629aa83c9bd1
>  - Merge with jdk-19+19
>  - ... and 7 more: https://git.openjdk.java.net/jdk/compare/4b2c8220...f06aff75

> The patch has support for x64 and aarch64 on the usual operating systems (Linux, macOS, and Windows). There are stubs (calling _Unimplemented_) for zero and some of the other ports. Additional ports can be contributed via PRs against the fibers branch in the loom repo.

So, does this PR pass current GHA checks? I see they are not enabled for this PR. It would be unfortunate for this large integration to break builds/tests for smaller PRs that would follow it.

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PR: https://git.openjdk.java.net/jdk/pull/8166