[jdk22u] RFR: 8325754: Dead AbstractQueuedSynchronizer$ConditionNodes survive minor garbage collections
Neethu Prasad
duke at openjdk.org
Tue Jun 18 16:21:45 UTC 2024
**Notes**
Backport of [JDK-8325754](https://bugs.openjdk.org/browse/JDK-8325754).
Unlink 'ConditionNode' before they are transferred to the sync queue as G1 seems to be able to collect “dead” ConditionNode instances during minor collections only if no formerly alive ConditionNode instances were promoted to the old generation and died there, which often cannot be avoided since e.g. on application startup many objects are promoted to the old generation after a few collections.
**Verification**
* jdk_util, Tier 1 & Tier 2 tests passed.
* Ran G1LoiteringConditionNodes.java (sample code from bug description) and verified that YG GC time is not increasing after full GC.
_Before PR_
dev-dsk-neethp-jdk-2c-ad54955c % /home/neethp/Development/jdk22u/build/linux-x86_64-server-release/images/jdk/bin/java -Xms2048m -Xmx2048m -XX:+UseG1GC -XX:+UnlockExperimentalVMOptions -XX:G1MaxNewSizePercent=20 '-Xlog:gc*,gc+age*=trace' -cp . G1LoiteringConditionNodes | grep -E 'Pause.*ms'
[0.965s][info ][gc ] GC(0) Pause Young (Normal) (G1 Evacuation Pause) 103M->1M(2048M) 5.021ms
[2.578s][info ][gc ] GC(1) Pause Young (Normal) (G1 Evacuation Pause) 155M->1M(2048M) 2.136ms
[6.991s][info ][gc ] GC(2) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.413ms
[11.329s][info ][gc ] GC(3) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 3.011ms
[15.696s][info ][gc ] GC(4) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 3.480ms
[20.099s][info ][gc ] GC(5) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 3.049ms
[24.522s][info ][gc ] GC(6) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.911ms
[28.952s][info ][gc ] GC(7) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.860ms
[33.381s][info ][gc ] GC(8) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.503ms
[37.810s][info ][gc ] GC(9) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.744ms
[42.243s][info ][gc ] GC(10) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.975ms
[46.684s][info ][gc ] GC(11) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 3.122ms
[51.127s][info ][gc ] GC(12) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.998ms
[55.548s][info ][gc ] GC(13) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 3.299ms
[59.986s][info ][gc ] GC(14) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.598ms
[64.418s][info ][gc ] GC(15) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.789ms
[68.848s][info ][gc ] GC(16) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.097ms
[73.271s][info ][gc ] GC(17) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.081ms
[77.692s][info ][gc ] GC(18) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.006ms
[82.113s][info ][gc ] GC(19) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.200ms
[86.551s][info ][gc ] GC(20) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.198ms
[90.996s][info ][gc ] GC(21) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.294ms
[95.435s][info ][gc ] GC(22) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.004ms
[99.871s][info ][gc ] GC(23) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.336ms
[104.303s][info ][gc ] GC(24) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.160ms
[108.730s][info ][gc ] GC(25) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.281ms
[113.155s][info ][gc ] GC(26) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.225ms
[117.592s][info ][gc ] GC(27) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.019ms
[120.104s][info ][gc ] GC(28) Pause Full (System.gc()) 230M->1M(2048M) 36.340ms
[124.512s][info ][gc ] GC(29) Pause Young (Normal) (G1 Evacuation Pause) 410M->1M(2048M) 4.144ms
[128.914s][info ][gc ] GC(30) Pause Young (Normal) (G1 Evacuation Pause) 409M->2M(2048M) 4.628ms
[133.310s][info ][gc ] GC(31) Pause Young (Normal) (G1 Evacuation Pause) 409M->2M(2048M) 4.521ms
[137.702s][info ][gc ] GC(32) Pause Young (Normal) (G1 Evacuation Pause) 409M->3M(2048M) 5.135ms
[142.103s][info ][gc ] GC(33) Pause Young (Normal) (G1 Evacuation Pause) 410M->3M(2048M) 4.669ms
[146.507s][info ][gc ] GC(34) Pause Young (Normal) (G1 Evacuation Pause) 409M->3M(2048M) 5.043ms
[150.904s][info ][gc ] GC(35) Pause Young (Normal) (G1 Evacuation Pause) 409M->4M(2048M) 5.489ms
[155.290s][info ][gc ] GC(36) Pause Young (Normal) (G1 Evacuation Pause) 409M->4M(2048M) 5.246ms
[159.679s][info ][gc ] GC(37) Pause Young (Normal) (G1 Evacuation Pause) 409M->5M(2048M) 5.922ms
[164.070s][info ][gc ] GC(38) Pause Young (Normal) (G1 Evacuation Pause) 410M->5M(2048M) 6.073ms
[168.447s][info ][gc ] GC(39) Pause Young (Normal) (G1 Evacuation Pause) 409M->6M(2048M) 5.724ms
[172.817s][info ][gc ] GC(40) Pause Young (Normal) (G1 Evacuation Pause) 410M->6M(2048M) 6.366ms
[177.185s][info ][gc ] GC(41) Pause Young (Normal) (G1 Evacuation Pause) 409M->6M(2048M) 6.147ms
[181.550s][info ][gc ] GC(42) Pause Young (Normal) (G1 Evacuation Pause) 409M->7M(2048M) 7.172ms
[185.889s][info ][gc ] GC(43) Pause Young (Normal) (G1 Evacuation Pause) 409M->8M(2048M) 6.288ms
[190.242s][info ][gc ] GC(44) Pause Young (Normal) (G1 Evacuation Pause) 410M->8M(2048M) 7.327ms
[194.583s][info ][gc ] GC(45) Pause Young (Normal) (G1 Evacuation Pause) 410M->8M(2048M) 7.143ms
[198.920s][info ][gc ] GC(46) Pause Young (Normal) (G1 Evacuation Pause) 410M->9M(2048M) 6.899ms
_After this change_
dev-dsk-neethp-jdk-2c-ad54955c % /home/neethp/Development/jdk22u/build/linux-x86_64-server-release/images/jdk/bin/java -Xms2048m -Xmx2048m -XX:+UseG1GC -XX:+UnlockExperimentalVMOptions -XX:G1MaxNewSizePercent=20 '-Xlog:gc*,gc+age*=trace' -cp . G1LoiteringConditionNodes | grep -E 'Pause.*ms'
[0.951s][info ][gc ] GC(0) Pause Young (Normal) (G1 Evacuation Pause) 103M->1M(2048M) 5.572ms
[2.572s][info ][gc ] GC(1) Pause Young (Normal) (G1 Evacuation Pause) 155M->1M(2048M) 2.317ms
[6.975s][info ][gc ] GC(2) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.753ms
[11.312s][info ][gc ] GC(3) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 3.230ms
[15.691s][info ][gc ] GC(4) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 3.104ms
[20.092s][info ][gc ] GC(5) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.668ms
[24.517s][info ][gc ] GC(6) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.479ms
[28.940s][info ][gc ] GC(7) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.326ms
[33.360s][info ][gc ] GC(8) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.528ms
[37.777s][info ][gc ] GC(9) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.501ms
[42.205s][info ][gc ] GC(10) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.843ms
[46.637s][info ][gc ] GC(11) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.988ms
[51.075s][info ][gc ] GC(12) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.292ms
[55.500s][info ][gc ] GC(13) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.189ms
[59.953s][info ][gc ] GC(14) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.528ms
[64.397s][info ][gc ] GC(15) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.513ms
[68.839s][info ][gc ] GC(16) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.191ms
[73.267s][info ][gc ] GC(17) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.096ms
[77.696s][info ][gc ] GC(18) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.598ms
[82.131s][info ][gc ] GC(19) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.438ms
[86.560s][info ][gc ] GC(20) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.162ms
[90.988s][info ][gc ] GC(21) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.145ms
[95.412s][info ][gc ] GC(22) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.095ms
[99.848s][info ][gc ] GC(23) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.407ms
[104.272s][info ][gc ] GC(24) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.226ms
[108.704s][info ][gc ] GC(25) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.741ms
[113.126s][info ][gc ] GC(26) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.851ms
[117.552s][info ][gc ] GC(27) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.349ms
[120.080s][info ][gc ] GC(28) Pause Full (System.gc()) 232M->1M(2048M) 33.952ms
[124.485s][info ][gc ] GC(29) Pause Young (Normal) (G1 Evacuation Pause) 410M->1M(2048M) 2.428ms
[128.891s][info ][gc ] GC(30) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.091ms
[133.289s][info ][gc ] GC(31) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.341ms
[137.707s][info ][gc ] GC(32) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.197ms
[142.122s][info ][gc ] GC(33) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.030ms
[146.525s][info ][gc ] GC(34) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.142ms
[150.931s][info ][gc ] GC(35) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.271ms
[155.336s][info ][gc ] GC(36) Pause Young (Normal) (G1 Evacuation Pause) 409M->1M(2048M) 2.309ms
-------------
Commit messages:
- Backport 60cbf2925024b1c2253256688ae41741fff0a860
Changes: https://git.openjdk.org/jdk22u/pull/249/files
Webrev: https://webrevs.openjdk.org/?repo=jdk22u&pr=249&range=00
Issue: https://bugs.openjdk.org/browse/JDK-8325754
Stats: 10 lines in 2 files changed: 10 ins; 0 del; 0 mod
Patch: https://git.openjdk.org/jdk22u/pull/249.diff
Fetch: git fetch https://git.openjdk.org/jdk22u.git pull/249/head:pull/249
PR: https://git.openjdk.org/jdk22u/pull/249
More information about the jdk-updates-dev
mailing list