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8297313: Refactor APIs for calculating address of CDS archive heap regions #11257

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iklam
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@iklam iklam commented Nov 21, 2022

In anticipation of the following RFEs:

  • JDK-8296263: Uniform APIs for using archived heap regions
  • JDK-8296344: Remove dependency on G1 for writing the CDS archive heap

We need to clean up the APIs for calculating the addresses of CDS archive heap regions. The current APIs have confusing names and the implementation is convoluted.

The proposal is to change the above to three APIs with easy-to-understand semantics:

// The actual address of this region during dump time.
address heap_region_dumptime_address(FileMapRegion* r)

// The address where this region can be mapped into the runtime heap without
// patching any of the pointers that are embedded in this region.
address heap_region_requested_address(FileMapRegion* r)

// The address where this shared heap region is actually mapped at runtime.
address heap_region_mapped_address(FileMapRegion* r)

The meaning of the CDSFileMapRegion::_mapping_offset field is changed slightly to simplify the implementation of the above 3 functions. Comments are improved explain what's going on.

With the above changes, FileMapInfo::map_heap_regions_impl() can also be simplified significantly.


Testing: tiers 1-4


Misc changes:

  • added more assertions about exactly which combinations of collector and oop encoding mode are supported
    • Specifically, uncompressed oops for non-G1 collectors are currently not supported;
    • Change error message accordingly when the user selects an unsupported combination.

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  • JDK-8297313: Refactor APIs for calculating address of CDS archive heap regions

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Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk pull/11257/head:pull/11257
$ git checkout pull/11257

Update a local copy of the PR:
$ git checkout pull/11257
$ git pull https://git.openjdk.org/jdk pull/11257/head

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Checkout this PR locally:
$ git pr checkout 11257

View PR using the GUI difftool:
$ git pr show -t 11257

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Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/11257.diff

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bridgekeeper bot commented Nov 21, 2022

👋 Welcome back iklam! 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 openjdk bot added the rfr Pull request is ready for review label Nov 21, 2022
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openjdk bot commented Nov 21, 2022

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

  • hotspot-runtime

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.

@openjdk openjdk bot added the hotspot-runtime hotspot-runtime-dev@openjdk.org label Nov 21, 2022
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mlbridge bot commented Nov 21, 2022

Webrevs

@iklam
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iklam commented Nov 21, 2022

Note: this is a redo of the withdrawn RFE JDK-8296155 (Simplify CDS heap region address calculation, see #10923).

While reviewing JDK-8296263 (Uniform APIs for using archived heap regions, see #10970) and discussing with its author, @ashu-mehra, I realized that the the APIs for calculating the addresses of CDS archive heap regions are problematic and will hinder further development. I also realized that JDK-8296155 was not fixing the problem in the right direction. Therefore, I withdrew JDK-8296155 and I am trying again with this RFE.

Thanks to @ashu-mehra for his insights and contributions to the proposed design.

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@matias9927 matias9927 left a comment

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Looks good to me!

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@calvinccheung calvinccheung left a comment

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Looks good. One nit below.

src/hotspot/share/cds/archiveHeapLoader.hpp Outdated Show resolved Hide resolved
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openjdk bot commented Nov 30, 2022

@iklam 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:

8297313: Refactor APIs for calculating address of CDS archive heap regions

Reviewed-by: matsaave, ccheung

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 22 new commits pushed to the master branch:

  • 0962957: 8297449: Update JInternalFrame Metal Border code
  • 9f94cbe: 8271519: java/awt/event/SequencedEvent/MultipleContextsFunctionalTest.java failed with "Total [200] - Expected [400]"
  • c70d1e1: 8296710: Update to use jtreg 7.1
  • 4899d78: 8293294: Remove dead code in Parse::check_interpreter_type
  • 5459b11: 8297033: G1: Improve logging for Remembered Sets
  • c6156f9: 8297561: Redundant index check in String.offsetByCodePoints()
  • eec24aa: 8295350: JFR: Add stop methods for recording streams
  • 9430f3e: 8297934: [BACKOUT] Compiler should only use verified interface types for optimization
  • 2cb64a7: 8294943: Implement record patterns in enhanced for
  • fc9d419: 8297928: Update jdk.internal.javac.PreviewFeature.Feature to reflect JEP 432 and JEP 433
  • ... and 12 more: https://git.openjdk.org/jdk/compare/3b513a4f5cc9b607f93dcc9d1ba52280a2cf42f0...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 openjdk bot added the ready Pull request is ready to be integrated label Nov 30, 2022
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iklam commented Dec 1, 2022

Thanks @matias9927 and @calvinccheung for the review.
/integrate

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openjdk bot commented Dec 1, 2022

Going to push as commit 391599b.
Since your change was applied there have been 22 commits pushed to the master branch:

  • 0962957: 8297449: Update JInternalFrame Metal Border code
  • 9f94cbe: 8271519: java/awt/event/SequencedEvent/MultipleContextsFunctionalTest.java failed with "Total [200] - Expected [400]"
  • c70d1e1: 8296710: Update to use jtreg 7.1
  • 4899d78: 8293294: Remove dead code in Parse::check_interpreter_type
  • 5459b11: 8297033: G1: Improve logging for Remembered Sets
  • c6156f9: 8297561: Redundant index check in String.offsetByCodePoints()
  • eec24aa: 8295350: JFR: Add stop methods for recording streams
  • 9430f3e: 8297934: [BACKOUT] Compiler should only use verified interface types for optimization
  • 2cb64a7: 8294943: Implement record patterns in enhanced for
  • fc9d419: 8297928: Update jdk.internal.javac.PreviewFeature.Feature to reflect JEP 432 and JEP 433
  • ... and 12 more: https://git.openjdk.org/jdk/compare/3b513a4f5cc9b607f93dcc9d1ba52280a2cf42f0...master

Your commit was automatically rebased without conflicts.

@openjdk openjdk bot added the integrated Pull request has been integrated label Dec 1, 2022
@openjdk openjdk bot closed this Dec 1, 2022
@openjdk openjdk bot removed ready Pull request is ready to be integrated rfr Pull request is ready for review labels Dec 1, 2022
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openjdk bot commented Dec 1, 2022

@iklam Pushed as commit 391599b.

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

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