RFR: 8338737: Shenandoah: Reset marking bitmaps after the cycle [v3]

[Xiaolong Peng]

On Fri, 18 Oct 2024 00:27:09 GMT, Xiaolong Peng <xpeng at openjdk.org> wrote:

> It is not a crash, looks like it is not related, I'll run test w/o the change to verify:

I have run `TestGCOldWithShenandoah.java#generational ` on GenShen tip, looks likes GenShen has bug causing stale mark bits, although it is rare, the test failed after 73 repeats with crash:

#
# A fatal error has been detected by the Java Runtime Environment:
#
#  Internal Error (/home/xlpeng/repos/jdk-xlpeng/src/hotspot/share/gc/shenandoah/shenandoahConcurrentGC.cpp:622), pid=26873, tid=26959
#  assert(_generation->is_bitmap_clear()) failed: need clear marking bitmap
#
# JRE version: OpenJDK Runtime Environment (24.0) (fastdebug build 24-internal-adhoc.xlpeng.jdk-xlpeng)
# Java VM: OpenJDK 64-Bit Server VM (fastdebug 24-internal-adhoc.xlpeng.jdk-xlpeng, mixed mode, sharing, tiered, compressed oops, compressed class ptrs, shenandoah gc, linux-amd64)
# Problematic frame:
# V  [libjvm.so+0x172ac44]  ShenandoahConcurrentGC::op_init_mark()+0x384
#
# No core dump will be written. Core dumps have been disabled. To enable core dumping, try "ulimit -c unlimited" before starting Java again
#
# An error report file with more information is saved as:
# /local/home/xlpeng/repos/jdk-xlpeng/build/linux-x86_64-server-fastdebug/test-support/jtreg_test_hotspot_jtreg_gc_stress_gcold_TestGCOldWithShenandoah_java_generational/scratch/0/hs_err_pid26873.log
#
# If you would like to submit a bug report, please visit:
#   https://bugreport.java.com/bugreport/crash.jsp
#

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PR Comment: https://git.openjdk.org/shenandoah/pull/516#issuecomment-2422722567