8351216: ZGC: Store NUMA node count

[jsikstro]

To avoid calling into os::Linux::max_numa_node() and in turn libnuma on every count lookup, I propose we instead store the count statically inside ZNUMA. This is perfectly fine since the value that we get from libnuma is configured once during initialization and never change during runtime.

The count is set during platform dependent initialization and the getter is now defined in the common code in ZNUMA.cpp. On operating systems that ZGC does not support NUMA for (BSD and Windows) we keep the current behavior by setting the count to 1.

This is also preparation work for the Mapped Cache (JDK-8350441).

Testing:

• Tiers 1-3
• GHA
• Verify that the count is set on a Linux system with NUMA hardware

---

Progress

• Change must be properly reviewed (1 review required, with at least 1 Reviewer)
• Change must not contain extraneous whitespace
• Commit message must refer to an issue

Issue

• JDK-8351216: ZGC: Store NUMA node count (Enhancement - P4)

Reviewers

• Stefan Johansson (@kstefanj - Reviewer) Review applies to a2acf21a
• Erik Österlund (@fisk - Reviewer) Review applies to a2acf21a
• Thomas Schatzl (@tschatzl - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk.git pull/23922/head:pull/23922
$ git checkout pull/23922

Update a local copy of the PR:
$ git checkout pull/23922
$ git pull https://git.openjdk.org/jdk.git pull/23922/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 23922

View PR using the GUI difftool:
$ git pr show -t 23922

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/23922.diff

Using Webrev

Link to Webrev Comment

[bridgekeeper]

👋 Welcome back jsikstro! 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]

@jsikstro 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:

8351216: ZGC: Store NUMA node count

Reviewed-by: tschatzl, sjohanss, eosterlund

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 123 new commits pushed to the master branch:

• 82eb780: 8351349: GSSUtil.createSubject has outdated access control context and policy related text
• c3db667: 8351542: LIBMANAGEMENT_OPTIMIZATION remove special optimization settings
• 375722f: 8351839: RISC-V: Fix base offset calculation introduced in JDK-8347489
• 4c5956d: 8350866: [x86] Add C1 intrinsics for CRC32-C
• 9c00331: 8330469: C2: Remove or change "PrintOpto && VerifyLoopOptimizations" as printing code condition
• c18494d: 8351108: ImageIO.write(..) fails with exception when writing JPEG with IndexColorModel
• 86860ca: 8346916: [REDO] align_up has potential overflow
• a33b1f7: 8345298: RISC-V: Add riscv backend for Float16 operations - scalar
• 6241d09: 8351861: RISC-V: add simple assert at arrays_equals_v
• 0e7d460: 8351662: [Test] RISC-V: enable bunch of IR test
• ... and 113 more: https://git.openjdk.org/jdk/compare/8073914af7d4ddd7bbd93d75104c7637e38a7ad9...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.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

[openjdk]

@jsikstro The following label will be automatically applied to this pull request:

• hotspot

When this pull request is ready to be reviewed, an "RFR" email will be sent to the corresponding mailing list. If you would like to change these labels, use the /label pull request command.

[mlbridge]

Webrevs

• 02: Full - Incremental (bdfcc781)
• 01: Full - Incremental (45dc106a)
• 00: Full (a2acf21a)

[jsikstro]

/label add hotspot-gc
/label remove hotspot

[openjdk]

@jsikstro
The hotspot-gc label was successfully added.

[openjdk]

@jsikstro
The hotspot label was successfully removed.

[kstefanj]

Looks good.

[fisk]

Looks good.

[jsikstro]

Thank you for the reviews!
/integrate

[openjdk]

Going to push as commit 7e3bc81.
Since your change was applied there have been 123 commits pushed to the master branch:

• 82eb780: 8351349: GSSUtil.createSubject has outdated access control context and policy related text
• c3db667: 8351542: LIBMANAGEMENT_OPTIMIZATION remove special optimization settings
• 375722f: 8351839: RISC-V: Fix base offset calculation introduced in JDK-8347489
• 4c5956d: 8350866: [x86] Add C1 intrinsics for CRC32-C
• 9c00331: 8330469: C2: Remove or change "PrintOpto && VerifyLoopOptimizations" as printing code condition
• c18494d: 8351108: ImageIO.write(..) fails with exception when writing JPEG with IndexColorModel
• 86860ca: 8346916: [REDO] align_up has potential overflow
• a33b1f7: 8345298: RISC-V: Add riscv backend for Float16 operations - scalar
• 6241d09: 8351861: RISC-V: add simple assert at arrays_equals_v
• 0e7d460: 8351662: [Test] RISC-V: enable bunch of IR test
• ... and 113 more: https://git.openjdk.org/jdk/compare/8073914af7d4ddd7bbd93d75104c7637e38a7ad9...master

Your commit was automatically rebased without conflicts.

[openjdk]

@jsikstro Pushed as commit 7e3bc81.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.