8310743: assert(reserved_rgn != nullptr) failed: Add committed region, No reserved region found

[xmas92]

Backport of JDK-8310743

JDK-8309675 tried to solve the issue of NMT reporting to much committed memory by faking the virtual addresses registered when committing physical memory. This mapping was simply the virtual address = physical offset in backing file + heap base. This works when ZGC gets a contiguous heap which starts at the heap base. However fails if it does not start at the heap base or is discontiguous.

This proposal fixes this by keeping track of all the reserved virtual address ranges and by creating a mapping from the physical offsets to the actual reserved virtual address ranges. If the physical offsets committed maps to multiple reserved ranges, it is processed as multiple commits.

The develop flag ZForceDiscontiguousHeapReservations is introduced to test the discontiguous heap feature and interactions.

This pull request contains a backport of commit f393975 from the openjdk/jdk repository.
With merge conflict in src/hotspot/share/gc/z/zPhysicalMemory.cpp (header includes) resolved.

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Progress

• Change must be properly reviewed (1 review required, with at least 1 Reviewer)
• Change must not contain extraneous whitespace
• Commit message must refer to an issue

Issue

• JDK-8310743: assert(reserved_rgn != nullptr) failed: Add committed region, No reserved region found (Bug - P2)

Reviewers

• Albert Mingkun Yang (@albertnetymk - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk21.git pull/92/head:pull/92
$ git checkout pull/92

Update a local copy of the PR:
$ git checkout pull/92
$ git pull https://git.openjdk.org/jdk21.git pull/92/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 92

View PR using the GUI difftool:
$ git pr show -t 92

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk21/pull/92.diff

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[bridgekeeper]

👋 Welcome back aboldtch! 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.

[openjdk]

@xmas92 The following label will be automatically applied to this pull request:

• hotspot-gc

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[mlbridge]

Webrevs

• 00: Full (059a660a)

[openjdk]

@xmas92 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:

8310743: assert(reserved_rgn != nullptr) failed: Add committed region, No reserved region found

Reviewed-by: ayang

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.

[xmas92]

/integrate

[openjdk]

Going to push as commit c9111d5.
Since your change was applied there have been 2 commits pushed to the master branch:

• 8d6ef6f: 8310549: avoid potential leaks in KeystoreImpl.m related to JNU_CHECK_EXCEPTION early returns
• 205dffe: 8254566: Clarify the spec of ClassLoader::getClassLoadingLock for non-parallel capable loader

Your commit was automatically rebased without conflicts.

[openjdk]

@xmas92 Pushed as commit c9111d5.

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