RFR (S) 8072693: [BACKOUT] GCCause should distinguish jcmd GC.run from System.gc()

Jesper Wilhelmsson jesper.wilhelmsson at oracle.com
Fri Feb 6 15:22:04 UTC 2015


Looks good.
/Jesper


> 6 feb 2015 kl. 16:10 skrev Mikael Gerdin <mikael.gerdin at oracle.com>:
> 
> Hi all,
> 
> There are some problems with the Diagnostic Command GCCause change, I suggest that we back out the change and reconsider its implementation.
> 
> [from the bug]
> The change is incomplete since several places in the GC code assumes that explicit gcs have the _java_lang_system_gc GCCause value in order to determine the behavior.
> For example:
> ParallelGC does not apply policy decisions on user-invoked GCs (decided by the GCCause)
> G1/CMS honors +ExplicitGCInvokesConcurrent based on the GCCause setting.
> This could cause problems for people expecting concurrent gcs when running the diagnostic command instead of a possibly several-second full gc pause.
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8072693
> Webrev: http://cr.openjdk.java.net/~mgerdin/8072693/webrev.0/
> 
> /Mikael


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