8265606: Reduce allocations in AdapterHandlerLibrary::get_adapter

[cl4es]

Use stack allocated arrays used when looking up and creating adapters. Resource allocate if number of args grows large, which is relatively rare.

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Progress

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Issue

• JDK-8265606: Reduce allocations in AdapterHandlerLibrary::get_adapter

Reviewers

• Ioi Lam (@iklam - Reviewer)

Reviewing

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[openjdk]

@cl4es The following label will be automatically applied to this pull request:

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[mlbridge]

Webrevs

• 01: Full - Incremental (f04d5474)
• 00: Full (f820f984)

[cl4es]

/label remove hotspot
/label add hotspot-runtime

[openjdk]

@cl4es
The hotspot label was successfully removed.

[openjdk]

@cl4es
The hotspot-runtime label was successfully added.

[iklam]

Was this line changed by mistake? The rest of the PR looks good to me.

[cl4es]

It was intentional, but it's also a bit of a scope creep: this method is about creating and returning the VMRegPair array, but it also resource-allocs this sig_bt array and keeps it alive for however long the regs array is kept alive, which means we hold on to a bit more memory for longer for no reason.

[iklam]

The think the original code was written to avoid allocating large arrays on the stack.

[cl4es]

Ok, I reverted this change. It's not part of anything I know sees much use anyhow.

[openjdk]

@cl4es 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:

8265606: Reduce allocations in AdapterHandlerLibrary::get_adapter

Reviewed-by: iklam

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 43 new commits pushed to the master branch:

• f45d460: 8265017: runtime/HiddenClasses/StressHiddenClasses.java timed out on Win* OCI
• 0136c89: 8265490: Unterminated string passed to FindClass() in hotspot test
• 325edbc: 8265450: Merge PreservedMarksSet::restore code paths
• b337f63: 8037397: RegEx pattern matching loses character class after intersection (&&) operator
• 07a7510: 8200145: Conditional expression mistakenly treated as standalone
• 41fc7dd: 8199079: Test javax/swing/UIDefaults/6302464/bug6302464.java is unstable
• 45c474a: 8168408: Test java/awt/Focus/ActualFocusedWindowTest/ActualFocusedWindowBlockingTest.java fails intermittentently on windows
• 18ee419: 8198422: Test java/awt/font/StyledMetrics/BoldSpace.java is unstable
• da86029: 8265326: Strange Characters in G1GC GC Log
• 7879adb: 8265343: Update Debian-based cross-compilation recipes
• ... and 33 more: https://git.openjdk.java.net/jdk/compare/ab2240741cfc7d10f012c1d588a92cf6f94e1de6...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.

[cl4es]

/integrate

[openjdk]

@cl4es Since your change was applied there have been 77 commits pushed to the master branch:

• bfc1cd8: 8264320: ShouldNotReachHere in Compile::print_inlining_move_to()
• 5db64c3: 8265268: Unify ReservedSpace reservation code in initialize and try_reserve_heap
• 191f1fc: 8265759: Shenandoah: Avoid race for referent in assert
• b3a319c: 8264842: IGV: different nodes sharing idx are treated as equal
• 95f0fd6: 8265696: Move CDS sources to src/hotspot/shared/cds
• a715b09: 8265798: Minimal build broken by JDK-8261090
• 13d3263: 8265484: Fix up TRAPS usage in GenerateOopMap::compute_map and callers
• a8ddbd1: 8265683: vmTestbase/nsk/jdb tests failed with "JDWP exit error AGENT_ERROR_INTERNAL(181)"
• 7a55914: 8264196: Change link_and_cleanup_shared_classes(CATCH) to CHECK
• b84f690: 8265793: Remove duplicate jtreg TEST.groups references for some client tests
• ... and 67 more: https://git.openjdk.java.net/jdk/compare/ab2240741cfc7d10f012c1d588a92cf6f94e1de6...master

Your commit was automatically rebased without conflicts.

Pushed as commit 891f72f.

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