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Merged
dsouzai merged 1 commit into from
Dec 4, 2025
Merged

Changes to memory disclaim heuristics #23049

dsouzai merged 1 commit into from
Dec 4, 2025
+67 −52

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@mpirvu
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@mpirvu mpirvu commented Dec 2, 2025

This commit performs the following changes to memory disclaim heuristics:

  • The prefered location for disclaimed memory is now swap (used to be /tmp)
  • If swap is not available (or disallowed through -Xjit:dontDisclaimMemoryOnSwap) then the JIT will attempt to use /tmp
  • Disclaim is avoided if less than 1GB of disk space is available (on swap or /tmp respectively). This threshold can be changed with -Xjit:minDiskSpaceForDisclaim= (in MB)

@mpirvu mpirvu requested a review from dsouzai as a code owner December 2, 2025 16:36
@dsouzai dsouzai self-assigned this Dec 2, 2025
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dsouzai commented Dec 2, 2025

jenkins test sanity.function all jdk21

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mpirvu commented Dec 2, 2025

I discovered a potential 32-bit overflow when shifting J9::Options::_minDiskSpaceForDisclaimMB << 20 to compute size in bytes.
I addressed that issue in the forced push.

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mpirvu commented Dec 2, 2025

jenkins test sanity.function all jdk21

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mpirvu commented Dec 2, 2025

jenkins test sanity.functional all jdk21

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mpirvu commented Dec 3, 2025

There were two failures:
On AIX J9vmTest_1_FAILED failed while executing j9vm.test.arraylets.ArrayletAllocateTest:

        +++ j9vm.test.arraylets.ArrayletAllocateTest: +++
        command: /home/jenkins/workspace/Test_openjdk21_j9_sanity.functional_ppc64_aix_Personal_testList_1/jdkbinary/j2sdk-image/bin/java  -Xgcpolicy:metronome -Xnocompressedrefs  -Xdump -Xms63m -Xmx63m  -Xdisableexcessivegc   -classpath /home/jenkins/workspace/Test_openjdk21_j9_sanity.functional_ppc64_aix_Personal_testList_1/aqa-tests/TKG/../../jvmtest/functional/VM_Test/VM_Test.jar:/home/jenkins/workspace/Test_openjdk21_j9_sanity.functional_ppc64_aix_Personal_testList_1/../../externalDependency/lib/asm-all.jar  j9vm.test.arraylets.ArrayletAllocateTest 

        JVMDUMP055I Processing dump event "systhrow", detail "java/lang/OutOfMemoryError", exception "Java heap space" at 2025/12/02 20:54:13 - please wait.
        JVMDUMP032I JVM requested System dump using '/home/jenkins/workspace/Test_openjdk21_j9_sanity.functional_ppc64_aix_Personal_testList_1/aqa-tests/TKG/output_17647074713425/J9vmTest_1/core.20251202.205413.27853180.0001.dmp' in response to an event
        JVMDUMP010I System dump written to /home/jenkins/workspace/Test_openjdk21_j9_sanity.functional_ppc64_aix_Personal_testList_1/aqa-tests/TKG/output_17647074713425/J9vmTest_1/core.20251202.205413.27853180.0001.dmp
        JVMDUMP032I JVM requested Heap dump using '/home/jenkins/workspace/Test_openjdk21_j9_sanity.functional_ppc64_aix_Personal_testList_1/aqa-tests/TKG/output_17647074713425/J9vmTest_1/heapdump.20251202.205413.27853180.0002.phd' in response to an event
        JVMDUMP010I Heap dump written to /home/jenkins/workspace/Test_openjdk21_j9_sanity.functional_ppc64_aix_Personal_testList_1/aqa-tests/TKG/output_17647074713425/J9vmTest_1/heapdump.20251202.205413.27853180.0002.phd
        JVMDUMP032I JVM requested Java dump using '/home/jenkins/workspace/Test_openjdk21_j9_sanity.functional_ppc64_aix_Personal_testList_1/aqa-tests/TKG/output_17647074713425/J9vmTest_1/javacore.20251202.205413.27853180.0003.txt' in response to an event
        JVMDUMP010I Java dump written to /home/jenkins/workspace/Test_openjdk21_j9_sanity.functional_ppc64_aix_Personal_testList_1/aqa-tests/TKG/output_17647074713425/J9vmTest_1/javacore.20251202.205413.27853180.0003.txt
        JVMDUMP032I JVM requested Snap dump using '/home/jenkins/workspace/Test_openjdk21_j9_sanity.functional_ppc64_aix_Personal_testList_1/aqa-tests/TKG/output_17647074713425/J9vmTest_1/Snap.20251202.205413.27853180.0004.trc' in response to an event
        JVMDUMP010I Snap dump written to /home/jenkins/workspace/Test_openjdk21_j9_sanity.functional_ppc64_aix_Personal_testList_1/aqa-tests/TKG/output_17647074713425/J9vmTest_1/Snap.20251202.205413.27853180.0004.trc
        JVMDUMP056I Processed dump event "systhrow", detail "java/lang/OutOfMemoryError" at 2025/12/02 20:54:16 (2.716 seconds).
        Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
        	at j9vm.test.arraylets.ArrayletAllocateTest.main(ArrayletAllocateTest.java:79)
        non-zero exit value: 1
        *** Test FAILED *** (j9vm.test.arraylets.ArrayletAllocateTest)

On Windows two SCC tests failed, mostly when trying to destroy a SCC:

        ---SUMMARY OF FAILED TESTS---
        Test 58 clean-up
        Test 69-f: cleanup
        Test 71-b: Re-use the shared cache in readonly mode, which should detect the page difference
        Test 71-c: Re-use the shared cache, which should detect the page difference

        testSCCMLTests1_openj9_3_FAILED

        ---SUMMARY OF FAILED TESTS---
        Test 67-c: Clean up
        Test 72-d: destroy cache for cleanup
        -----------------------------
        
        -----------------------------------
        testSCCMLTests1_openj9_2_FAILED

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mpirvu commented Dec 3, 2025 •
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The same failures occurred again in small grinders. The platforms involved, AIX and Windows, do not use disclaiming. I am going to slightly change the code to be absolutely sure that we don't execute any of the disclaiming code on platforms other than Linux.

@mpirvu
Changes to memory disclaim heuristics
4033022 
This commit performs the following changes to memory disclaim heuristics:
- The prefered location for disclaimed memory is now swap (used to be /tmp)
- If swap is not available (or disallowed through -Xjit:dontDisclaimMemoryOnSwap)
  then the JIT will attempt to use /tmp
- Disclaim is avoided if less than 1GB of disk space is available
  (on swap or /tmp respectively). This threshold can be changed with
  -Xjit:minDiskSpaceForDisclaim=<NNN> (in MB)

Signed-off-by: Marius Pirvu <mpirvu@ca.ibm.com>
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mpirvu commented Dec 3, 2025

jenkins test sanity all jdk21

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mpirvu commented Dec 3, 2025

FYI @JamesKingdon since some of our customers raised issues with respect to disclaiming.

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dsouzai commented Dec 3, 2025

jdk11 win failure is infra related:

[2025-12-03T19:58:08.296Z] Test result: FAILED
[2025-12-03T19:58:08.296Z]  [ERR] JVMSHRC241E Error: unable to delete shared class cache file
[2025-12-03T19:58:08.296Z]  [ERR] JVMSHRC336E Port layer error code = -102
[2025-12-03T19:58:08.296Z]  [ERR] JVMSHRC337E Platform error message: (5) Access is denied.

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mpirvu commented Dec 4, 2025

All the tests passed except the one on windows due to infra.
This PR is ready to be merged.

@dsouzai dsouzai merged commit 297d476 into eclipse-openj9:master Dec 4, 2025
25 of 27 checks passed
@mpirvu mpirvu mentioned this pull request Dec 5, 2025
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