RFR: JDK-8141530: Remove G1RecordHRRSOops and G1RecordHRRSEvents

Bengt Rutisson bengt.rutisson at oracle.com
Fri Nov 6 05:24:37 UTC 2015


Thanks, Mikael!

Bengt

On 2015-11-05 15:05, Mikael Gerdin wrote:
> Hi Bengt,
>
> On 2015-11-05 13:14, Bengt Rutisson wrote:
>>
>> Hi everyone,
>>
>> Could I have a couple of reviews for this change to remove some unused
>> debugging code?
>>
>> http://cr.openjdk.java.net/~brutisso/8141530/webrev.00/
>
> Looks good.
>
> /Mikael
>
>> https://bugs.openjdk.java.net/browse/JDK-8141530
>>
>> Thanks,
>> Bengt
>>
>>  From the bug report:
>>
>> The two develop flags G1RecordHRRSOops and G1RecordHRRSEvents seem to
>> have been added to record information about remembered set management
>> that could be useful for debugging.
>>
>> The information they record is never printed.
>> (HeapRegionRemSet::print_recorded() is never called in the code). Thus
>> the only use case must be to call the print method from a debugging
>> session, such as for example in gdb.
>>
>> When I call HeapRegionRemSet::print_recorded() from gdb I get a SIGSEGV.
>> Same if I add a call to it from the end of a GC. See the partial hs_err
>> file below.
>>
>> Since this is broken debugging code that uses logging I think it is
>> better to remove it than to try to fix it and update it to use the
>> unified logging framework.
>>
>> #
>> # A fatal error has been detected by the Java Runtime Environment:
>> #
>> # SIGSEGV (0xb) at pc=0x00007ffff6461f3e, pid=9436, tid=9495
>> #
>> # JRE version: Java(TM) SE Runtime Environment (9.0) (build
>> 1.9.0-internal-fastdebug-brutisso_2015_10_30_09_20-b00)
>> # Java VM: Java HotSpot(TM) 64-Bit Server VM
>> (1.9.0-internal-fastdebug-brutisso_2015_10_30_09_20-b00, mixed mode,
>> tiered, compressed oops, g1 gc, linux-amd64)
>> # Problematic frame:
>> # V [libjvm.so+0xa8cf3e] HeapRegionRemSet::print_recorded()+0x13e
>> #
>> # Core dump will be written. Default location: Core dumps may be
>> processed with "/usr/share/apport/apport %p %s %c %P" (or dumping to
>> /localhome/repos/jdk9-hs-rt/hotspot/core.9436)
>> #
>> # If you would like to submit a bug report, please visit:
>> # http://bugreport.java.com/bugreport/crash.jsp
>> #
>>
>> --------------- S U M M A R Y ------------
>>
>> Command Line: -Xmx128m -XX:+UseG1GC -XX:+G1RecordHRRSOops
>> -XX:+G1RecordHRRSEvents -XX:+G1TraceHeapRegionRememberedSet TestGCOld 50
>> 1 20 10 10000
>>
>> Host: sthws37, Intel(R) Xeon(R) CPU E5-2665 0 @ 2.40GHz, 32 cores, 31G,
>> Ubuntu 14.04.3 LTS
>> Time: Thu Nov 5 12:53:47 2015 CET elapsed time: 81 seconds (0d 0h 1m 
>> 21s)
>>
>> --------------- T H R E A D ---------------
>>
>> Current thread (0x00007ffff02c8000): VMThread [stack:
>> 0x00007fff00200000,0x00007fff00301000] [id=9495]
>>
>> Stack: [0x00007fff00200000,0x00007fff00301000], sp=0x00007fff002ff840,
>> free space=1022k
>> Native frames: (J=compiled Java code, j=interpreted, Vv=VM code,
>> C=native code)
>> V [libjvm.so+0xa8cf3e] HeapRegionRemSet::print_recorded()+0x13e
>> V [libjvm.so+0x974c5d]
>> G1CollectedHeap::do_collection_pause_at_safepoint(double)+0xf6d
>> V [libjvm.so+0x125c09a] VM_G1IncCollectionPause::doit()+0xca
>> V [libjvm.so+0x125a455] VM_Operation::evaluate()+0xa5
>> V [libjvm.so+0x1257be4] 
>> VMThread::evaluate_operation(VM_Operation*)+0x154
>> V [libjvm.so+0x1258513] VMThread::loop()+0x4c3
>> V [libjvm.so+0x125874b] VMThread::run()+0xbb
>> V [libjvm.so+0xf5049a] java_start(Thread*)+0xca
>>
>>
>>
>>
>



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