8291302: ARM32: nmethod entry barriers support

[voitylov]

This PR implements nmethod entry barriers for ARM32. It has already been implemented for other ports and is related with JDK-8290025 "Remove the Sweeper".

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Progress

• Change must be properly reviewed (1 review required, with at least 1 Reviewer)
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• Commit message must refer to an issue

Issue

• JDK-8291302: ARM32: nmethod entry barriers support

Reviewers

• Erik Österlund (@fisk - Reviewer)
• Richard Reingruber (@reinrich - Reviewer) ⚠️ Review applies to 079a1a9b
• Martin Doerr (@TheRealMDoerr - Reviewer)
• Andrew Haley (@theRealAph - Reviewer) ⚠️ Review applies to 079a1a9b

Reviewing

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Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk pull/11442/head:pull/11442
$ git checkout pull/11442

Update a local copy of the PR:
$ git checkout pull/11442
$ git pull https://git.openjdk.org/jdk pull/11442/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 11442

View PR using the GUI difftool:
$ git pr show -t 11442

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/11442.diff

[bridgekeeper]

👋 Welcome back avoitylov! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

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[mlbridge]

Webrevs

• 04: Full - Incremental (aa7fc860)
• 03: Full - Incremental (079a1a9b)
• 02: Full - Incremental (02439515)
• 01: Full - Incremental (34a17994)
• 00: Full (828c39d0)

[voitylov]

Errors in pre-submit tests are clearly unrelated, GHA can't download the bundles for linux-x86:

Error: Unable to find an artifact with the name: bundles-linux-x86

[fisk]

When you call the nmethod entry barrier slow path, floating point arguments are live, but can get clobbered by the C++ runtime. You need to save them. That's probably why you can't print in the slow path without crashing.

[reinrich]

Hi Aleksei,
thanks for picking up the work on ARM32 support of nmethod entry barriers.
Is my assumption correct that ARM32 supports neither ZGC nor ShenandoahGC? If so you could simplify the implementation.
Thanks, Richard.

[voitylov]

@fisk @reinrich Thank you for your suggestions. This iteration saves floating registers and can successfully log deoptimization. I'd prefer to keep the code in line with the same code for other ports and not carve out memory barriers by hand, if @reinrich would agree. This also allows a more straightforward port for additional GCs in the future, should there be any demand.

[TheRealMDoerr]

Please note that the memory barrier has caused a performance regression on PPC64 (as on AArch64): https://bugs.openjdk.org/browse/JDK-8295069
I'd probably assert nmethod_patching_type() == NMethodPatchingType::stw_instruction_and_data_patch instead of emitting a memory barrier because LoadLoad may or may not be strong enough depending on usage (e.g. generational ZGC uses instruction patching as well).

[voitylov]

The removed membar can be added later if and when support for other GCs is added to ARM32.

[TheRealMDoerr]

LGTM, but I'm not an arm 32 expert.

[openjdk]

@voitylov This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8291302: ARM32: nmethod entry barriers support

Reviewed-by: eosterlund, rrich, mdoerr, aph

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 233 new commits pushed to the master branch:

• a9ce772: 8299437: Make InetSocketAddressHolder shallowly immutable
• 8afd665: 8299395: Remove metaprogramming/removeCV.hpp
• 3757433: 8295974: jni_FatalError and Xcheck:jni warnings should print the native stack when there are no Java frames
• 417d01e: 8299441: Fix typos in some test files under core-libs component
• 5b5552f: 8299483: ProblemList java/text/Format/NumberFormat/CurrencyFormat.java
• 67086eb: 8299030: Refactor ReservedSpace::reserve
• ce6395a: 8299397: Remove metaprogramming/isFloatingPoint.hpp
• 71a64a1: 8299399: Remove metaprogramming/isArray.hpp
• 532ccdb: 8299396: Remove metaprogramming/removeExtent.hpp
• 9d3d039: 8299402: Remove metaprogramming/isVolatile.hpp
• ... and 223 more: https://git.openjdk.org/jdk/compare/e555d5470536b8379179879ec7343e004be95e36...master

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

As you do not have Committer status in this project an existing Committer must agree to sponsor your change. Possible candidates are the reviewers of this PR (@fisk, @reinrich, @TheRealMDoerr, @theRealAph) but any other Committer may sponsor as well.

➡️ To flag this PR as ready for integration with the above commit message, type /integrate in a new comment. (Afterwards, your sponsor types /sponsor in a new comment to perform the integration).

[reinrich]

The changes look good to me. I'm not familiar with arm32 details, though.
You might want to open an RFE to port JDK-8290700 to arm32.
Thanks, Richard.

[bulasevich]

Looks good!

[voitylov]

@TheRealMDoerr @reinrich @bulasevich thank you for your reviews!

[voitylov]

@fisk do you have any further comments? I'd like to have this in to continue working on Loom.

[theRealAph]

Looks reasonable. Please consider my cleanups.

[voitylov]

Thanks @theRealAph . Your suggestions for cleanups are addressed.

[TheRealMDoerr]

Thanks for the cleanup! Still looks good. I think the PR is ready for integration. You have 3 reviews and the concerns were addressed.

[fisk]

Looks good.

[voitylov]

/integrate

[openjdk]

@voitylov
Your change (at version aa7fc86) is now ready to be sponsored by a Committer.

[TheRealMDoerr]

/sponsor

[openjdk]

Going to push as commit 245f0cf.
Since your change was applied there have been 233 commits pushed to the master branch:

• a9ce772: 8299437: Make InetSocketAddressHolder shallowly immutable
• 8afd665: 8299395: Remove metaprogramming/removeCV.hpp
• 3757433: 8295974: jni_FatalError and Xcheck:jni warnings should print the native stack when there are no Java frames
• 417d01e: 8299441: Fix typos in some test files under core-libs component
• 5b5552f: 8299483: ProblemList java/text/Format/NumberFormat/CurrencyFormat.java
• 67086eb: 8299030: Refactor ReservedSpace::reserve
• ce6395a: 8299397: Remove metaprogramming/isFloatingPoint.hpp
• 71a64a1: 8299399: Remove metaprogramming/isArray.hpp
• 532ccdb: 8299396: Remove metaprogramming/removeExtent.hpp
• 9d3d039: 8299402: Remove metaprogramming/isVolatile.hpp
• ... and 223 more: https://git.openjdk.org/jdk/compare/e555d5470536b8379179879ec7343e004be95e36...master

Your commit was automatically rebased without conflicts.

[openjdk]

@TheRealMDoerr @voitylov Pushed as commit 245f0cf.

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