8318507: G1: Improve remset clearing for humongous candidates

[tschatzl]

Hi all,

please review this small cleanup that merges two calls to HeapRegionRemSet::clear()/HeapRegionRemSet::set_state_complete() to a single call to clear() with appropriate parameters.

Also remove now obsolete asserts that are done in clear() already; actually the second one is wrong, there may be code roots attached to the region.

Testing: gha, tier1-5 almost done

Thanks,
Thomas

---

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Issue

• JDK-8318507: G1: Improve remset clearing for humongous candidates (Enhancement - P4)

Reviewers

• Ivan Walulya (@walulyai - Reviewer) ⚠️ Review applies to 6af1e899
• Albert Mingkun Yang (@albertnetymk - Reviewer)
• Hamlin Li (@Hamlin-Li - Reviewer)

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[bridgekeeper]

👋 Welcome back tschatzl! 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

• 01: Full - Incremental (2af41e00)
• 00: Full (6af1e899)

[walulyai]

LGTM!

[openjdk]

@tschatzl 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:

8318507: G1: Improve remset clearing for humongous candidates

Reviewed-by: iwalulya, ayang, mli

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 47 new commits pushed to the master branch:

• 4eab39d: 8318585: Rename CodeCache::UnloadingScope to UnlinkingScope
• ffadd63: 8317868: Add @sealedGraph to MethodHandleDesc and descendants
• ecd25e7: 8318484: Initial version of cdsConfig.hpp
• a876beb: 8316741: BasicStroke.createStrokedShape miter-limits failing on small shapes
• 4cf195f: 8318573: The nsk.share.jpda.SocketConnection should fail if socket was closed.
• af2f4bf: 8318622: ProblemList gc/cslocker/TestCSLocker.java on linux-x64 in Xcomp mode
• a1a62d9: 8306308: (ch) Writer created by Channels::newWriter may lose data
• 77b2394: 8318482: problemlist compiler/codecache/CheckLargePages.java on Linux-x64 until JDK-8317831 is fixed
• d3ebb4a: 8317373: Add Telia Root CA v2
• 66d90d5: 8318107: Un-ProblemList LocaleProvidersRun and CalendarDataRegression
• ... and 37 more: https://git.openjdk.org/jdk/compare/defc7e0f8d32e2dc62568f34d86d8f77a759e6ce...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.

[albertnetymk]

actually the second one is wrong, there may be code roots attached to the region.

occupancy_less_or_equal_than should have ensured that code-roots is empty. (The method name is not very obvious on that, IMO. Breaking it into two might be better.) I believe one can assert(r->rem_set()->is_complete() && r->rem_set()->is_empty(), "inv"); after clear(...).

[tschatzl]

actually the second one is wrong, there may be code roots attached to the region.

occupancy_less_or_equal_than should have ensured that code-roots is empty. (The method name is not very obvious on that, IMO. Breaking it into two might be better.) I believe one can assert(r->rem_set()->is_complete() && r->rem_set()->is_empty(), "inv"); after clear(...).

👍
This is similar to @Hamlin-Li 's question.

[Hamlin-Li]

LGTM.

[tschatzl]

Thanks @Hamlin-Li @albertnetymk @walulyai for your reviews.
/integrate

[openjdk]

Going to push as commit 729f4c5.
Since your change was applied there have been 47 commits pushed to the master branch:

• 4eab39d: 8318585: Rename CodeCache::UnloadingScope to UnlinkingScope
• ffadd63: 8317868: Add @sealedGraph to MethodHandleDesc and descendants
• ecd25e7: 8318484: Initial version of cdsConfig.hpp
• a876beb: 8316741: BasicStroke.createStrokedShape miter-limits failing on small shapes
• 4cf195f: 8318573: The nsk.share.jpda.SocketConnection should fail if socket was closed.
• af2f4bf: 8318622: ProblemList gc/cslocker/TestCSLocker.java on linux-x64 in Xcomp mode
• a1a62d9: 8306308: (ch) Writer created by Channels::newWriter may lose data
• 77b2394: 8318482: problemlist compiler/codecache/CheckLargePages.java on Linux-x64 until JDK-8317831 is fixed
• d3ebb4a: 8317373: Add Telia Root CA v2
• 66d90d5: 8318107: Un-ProblemList LocaleProvidersRun and CalendarDataRegression
• ... and 37 more: https://git.openjdk.org/jdk/compare/defc7e0f8d32e2dc62568f34d86d8f77a759e6ce...master

Your commit was automatically rebased without conflicts.

[openjdk]

@tschatzl Pushed as commit 729f4c5.

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