8268127: Shenandoah: Heap size may be too small for region to align to large page size

[zhengyu123]

I would like to backport this Shenandoah specific patch to 11u, which allows to fallback to regular pages for regions, if heap size is too small to allow regions to use large pages.

The original patch does not apply cleanly, resolved then manually.

Test:
Manually test to ensure large pages are used. Failed w/o the patch and passed with it.

---

Progress

• Change must not contain extraneous whitespace
• Commit message must refer to an issue
• Change must be properly reviewed

Issue

• JDK-8268127: Shenandoah: Heap size may be too small for region to align to large page size

Reviewers

• Roman Kennke (@rkennke - Committer)
• Aleksey Shipilev (@shipilev - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.java.net/jdk11u-dev pull/28/head:pull/28
$ git checkout pull/28

Update a local copy of the PR:
$ git checkout pull/28
$ git pull https://git.openjdk.java.net/jdk11u-dev pull/28/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 28

View PR using the GUI difftool:
$ git pr show -t 28

Using diff file

Download this PR as a diff file:
https://git.openjdk.java.net/jdk11u-dev/pull/28.diff

[bridgekeeper]

👋 Welcome back zgu! 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]

This backport pull request has now been updated with issue from the original commit.

[mlbridge]

Webrevs

• 00: Full (8d405b58)

[zhengyu123]

/integrate

[openjdk]

@zhengyu123 This PR has not yet been marked as ready for integration.

[openjdk]

@zhengyu123 This change now passes all automated pre-integration checks.

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

8268127: Shenandoah: Heap size may be too small for region to align to large page size

Reviewed-by: rkennke, shade

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 2 new commits pushed to the master branch:

• 4e19090: 8268103: JNI functions incorrectly return a double after JDK-8265836
• 37f36d5: 8265836: OperatingSystemImpl.getCpuLoad() returns incorrect CPU load inside a container

Please see this link for an up-to-date comparison between the source branch of this pull request and the master branch.
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.

[zhengyu123]

/integrate

[openjdk]

Going to push as commit 57d8e1e.
Since your change was applied there have been 2 commits pushed to the master branch:

• 4e19090: 8268103: JNI functions incorrectly return a double after JDK-8265836
• 37f36d5: 8265836: OperatingSystemImpl.getCpuLoad() returns incorrect CPU load inside a container

Your commit was automatically rebased without conflicts.

[openjdk]

@zhengyu123 Pushed as commit 57d8e1e.

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