8372250: Merge PtrQueue into SATBMarkQueue #28755

benty-amzn · 2025-12-10T18:26:16Z

This change merges PtrQueue into its only child class, SATBMarkQueue. The corresponding PtrQueueSet is merged with SATBMarkQueueSet, and G1SATBMarkQueueSet and ShenandoahSATBMarkQueueSet continue to inherit from that class.

There are few code modifications - most methods were moved directly from PtrQueue to SATBMarkQueue. The one meaningful change is to preserve SATBMarkQueue's call to filter(queue); before flush_queue.

This change passes all tier1 jtreg tests with both Shenandoah and G1 in local testing.

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Issue

JDK-8372250: Merge PtrQueue into SATBMarkQueue (Enhancement - P4)

Reviewers

Kim Barrett (@kimbarrett - Reviewer)
Ivan Walulya (@walulyai - Reviewer)
Thomas Schatzl (@tschatzl - Reviewer)
William Kemper (@earthling-amzn - Reviewer)

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$ git fetch https://git.openjdk.org/jdk.git pull/28755/head:pull/28755
$ git checkout pull/28755

Update a local copy of the PR:
$ git checkout pull/28755
$ git pull https://git.openjdk.org/jdk.git pull/28755/head

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$ git pr checkout 28755

View PR using the GUI difftool:
$ git pr show -t 28755

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https://git.openjdk.org/jdk/pull/28755.diff

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bridgekeeper · 2025-12-10T18:27:42Z

👋 Welcome back btaylor! 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 · 2025-12-10T18:29:56Z

@benty-amzn 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:

8372250: Merge PtrQueue into SATBMarkQueue

Reviewed-by: kbarrett, iwalulya, tschatzl, wkemper

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 89 new commits pushed to the master branch:

6ec36d3: 8373059: Test sun/security/provider/acvp/ML_DSA_Intrinsic_Test.java should pass on Aarch64
a99f340: 8371721: Refactor checkTrusted methods in X509TrustManagerImpl
d854a04: 8373411: Crash when PrintSharedArchiveAndExit is enabled but shared heap is disabled
... and 86 more: https://git.openjdk.org/jdk/compare/5ec5a6ea6c8e887b4e21f81e382f57129bffbab8...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 (@kimbarrett, @walulyai, @tschatzl, @earthling-amzn) 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).

openjdk · 2025-12-10T18:32:02Z

@benty-amzn The following label will be automatically applied to this pull request:

hotspot-gc

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 · 2025-12-10T19:24:15Z

Webrevs

kimbarrett

This looks mostly good, with just a few minor nits.

I think there may be further simplifications and cleanups possible, but
looking for those can be done later, once this relatively clean merging change
is done.

[appropriate place is not commentable in github diff]
SATBMarkQueueSet::enqueue_completed_buffer should no longer be virtual. (This
would have been caught if it had been changed to "override" once that was
permitted, but nobody got around to that.)

kimbarrett · 2025-12-10T21:05:41Z

src/hotspot/share/gc/shared/satbMarkQueue.cpp

+{}
+
+SATBMarkQueue::~SATBMarkQueue() {
+    assert(_buf == nullptr, "queue must be flushed before delete");


Too much indentation.

kimbarrett · 2025-12-10T21:07:47Z

src/hotspot/share/gc/shared/satbMarkQueue.cpp

+
+void SATBMarkQueueSet::deallocate_buffer(BufferNode* node) {
+  _allocator->release(node);
+}


Missing newline?

kimbarrett · 2025-12-10T21:20:55Z

src/hotspot/share/gc/shared/satbMarkQueue.hpp

+  void deallocate_buffer(BufferNode* node);
+
+  // A completed buffer is a buffer the mutator is finished with, and
+  // is ready to be processed by the collector.  It need not be full.


This comment (copied from ptrQueueSet) seems misplaced here. Perhaps it should be part of the
class description?

kimbarrett · 2025-12-10T21:32:08Z

src/hotspot/share/gc/shared/satbMarkQueue.hpp

+
+  // Installs a new buffer into queue.
+  void install_new_buffer(SATBMarkQueue& queue);
+


These helper functions hoisted from PtrQueueSet should be private rather than protected here.

kimbarrett · 2025-12-11T01:06:26Z

commit 148aa4f didn't address this comment:

[appropriate place is not commentable in github diff]
SATBMarkQueueSet::enqueue_completed_buffer should no longer be virtual. (This
would have been caught if it had been changed to "override" once that was
permitted, but nobody got around to that.)

kimbarrett

Looks good.

walulyai · 2025-12-12T08:25:20Z

src/hotspot/share/gc/shared/satbMarkQueue.hpp

 private:
+  NONCOPYABLE(SATBMarkQueue);
+
+  // The buffer.


We could refactor rename to _buffer so we don't need the comment above. But that does not have to be done as part of this change.

benty-amzn · 2025-12-12T16:23:27Z

/integrate

openjdk · 2025-12-12T16:23:52Z

@benty-amzn
Your change (at version 517b245) is now ready to be sponsored by a Committer.

earthling-amzn · 2025-12-12T16:26:11Z

/sponsor

openjdk · 2025-12-12T16:27:59Z

Going to push as commit 0eb2bcd.
Since your change was applied there have been 89 commits pushed to the master branch:

6ec36d3: 8373059: Test sun/security/provider/acvp/ML_DSA_Intrinsic_Test.java should pass on Aarch64
a99f340: 8371721: Refactor checkTrusted methods in X509TrustManagerImpl
d854a04: 8373411: Crash when PrintSharedArchiveAndExit is enabled but shared heap is disabled
... and 86 more: https://git.openjdk.org/jdk/compare/5ec5a6ea6c8e887b4e21f81e382f57129bffbab8...master

Your commit was automatically rebased without conflicts.

openjdk · 2025-12-12T16:28:10Z

@earthling-amzn @benty-amzn Pushed as commit 0eb2bcd.

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

8372250: Merge PtrQueue into SATBMarkQueue

fff7354

openjdk bot added the hotspot-gc [email protected] label Dec 10, 2025

benty-amzn added 2 commits December 10, 2025 18:39

Fix missing includes and whitespace in previous commit

7b80b1e

Additional jcheck whitespace fix

bc24bfb

openjdk bot added the rfr Pull request is ready for review label Dec 10, 2025

kimbarrett suggested changes Dec 10, 2025

View reviewed changes

Address PR feedback from kimbarrett

148aa4f

Remove virtual from SATBMarkQueueSet::enqueue_completed_buffer

517b245

kimbarrett approved these changes Dec 12, 2025

View reviewed changes

openjdk bot added the ready Pull request is ready to be integrated label Dec 12, 2025

walulyai approved these changes Dec 12, 2025

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tschatzl approved these changes Dec 12, 2025

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earthling-amzn approved these changes Dec 12, 2025

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openjdk bot added the sponsor Pull request is ready to be sponsored label Dec 12, 2025

openjdk bot added the integrated Pull request has been integrated label Dec 12, 2025

openjdk bot closed this Dec 12, 2025

openjdk bot removed ready Pull request is ready to be integrated rfr Pull request is ready for review sponsor Pull request is ready to be sponsored labels Dec 12, 2025


		// Installs a new buffer into queue.
		void install_new_buffer(SATBMarkQueue& queue);

8372250: Merge PtrQueue into SATBMarkQueue #28755

8372250: Merge PtrQueue into SATBMarkQueue #28755

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