RFR: 8279540: Shenandoah: Should only clear CLD::_claim_strong mark for strong CLD iterations
Zhengyu Gu
zgu at openjdk.java.net
Thu Jan 6 13:34:31 UTC 2022
JDK-8273559 started to use CLD::_claim_other for heap iteration in supporting multi-threaded heap walk. For regular CLD, it still uses CLD::_claim_strong, but for those walks, it clears all claim bits, instead of just _claim_strong bit.
I don't think it is a fatal bug, it just means heap iteration may walk a CLD by multiple workers, which impacts performance.
Test:
- [x] hotspot_gc_shenandoah
-------------
Commit messages:
- 8279540: Shenandoah: Should only clear CLD::_claim_strong mark for strong CLD iterations
Changes: https://git.openjdk.java.net/jdk/pull/6980/files
Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=6980&range=00
Issue: https://bugs.openjdk.java.net/browse/JDK-8279540
Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
Patch: https://git.openjdk.java.net/jdk/pull/6980.diff
Fetch: git fetch https://git.openjdk.java.net/jdk pull/6980/head:pull/6980
PR: https://git.openjdk.java.net/jdk/pull/6980
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