8276201: Shenandoah: Race results degenerated GC to enter wrong entry point

[zhengyu123]

This is a Shenandoah specific backport. It fixes a race that results degenerated GC to enter wrong degen entry point.

The original patch does not apply cleanly due to code divergence, especially the grand refactoring that is not in jdk11u. However, the backport is simple and straight forward.

Test:

• hotspot_gc_shenandoah

---

Progress

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

Issue

• JDK-8276201: Shenandoah: Race results degenerated GC to enter wrong entry point

Reviewers

• Aleksey Shipilev (@shipilev - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.java.net/jdk11u-dev pull/612/head:pull/612
$ git checkout pull/612

Update a local copy of the PR:
$ git checkout pull/612
$ git pull https://git.openjdk.java.net/jdk11u-dev pull/612/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 612

View PR using the GUI difftool:
$ git pr show -t 612

Using diff file

Download this PR as a diff file:
https://git.openjdk.java.net/jdk11u-dev/pull/612.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 (8fd54fbc)

[shipilev]

Looks fine.

[openjdk]

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

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

8276201: Shenandoah: Race results degenerated GC to enter wrong entry point

Reviewed-by: 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 no new commits pushed to the master branch. If another commit should be pushed before you perform the /integrate command, your PR will be automatically rebased. If you prefer to avoid any potential 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 35c045c.
Since your change was applied there have been 13 commits pushed to the master branch:

• 3593e1e: 8034084: nsk.nsk/jvmti/ThreadStart/threadstart003 Wrong number of thread end events
• 9f7729a: 8258457: testlibrary_tests/ctw/JarDirTest.java fails with InvalidPathException on windows
• 63848c5: 8201224: Make string buffer size dynamic in mlvmJvmtiUtils.c
• 18f16db: 8174819: java/nio/file/WatchService/LotsOfEvents.java fails intermittently
• 4b0cb20: 8204161: [TESTBUG] auto failed with the "Applet thread threw exception: java.lang.UnsupportedOperationException" exception
• f8553d3: 8208242: Add @requires to vmTestbase/gc/g1 tests
• 46d8523: 8261916: gtest/GTestWrapper.java vmErrorTest.unimplemented1_vm_assert failed
• 6ec651f: 8276550: Use SHA256 hash in build.tools.depend.Depend
• e608a20: 8236596: HttpClient leaves HTTP/2 sockets in CLOSE_WAIT, when using proxy tunnel
• c6242ed: 8276854: Windows GHA builds fail due to broken Cygwin
• ... and 3 more: https://git.openjdk.java.net/jdk11u-dev/compare/a15fa7a8360a1cf4d107800123945d6f06bbdc8d...master

Your commit was automatically rebased without conflicts.

[openjdk]

@zhengyu123 Pushed as commit 35c045c.

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