Request for Review (xs) - 8151845: Comment in globals.hpp for MetaspaceSize is incorrect.

Derek White derek.white at oracle.com
Wed Mar 16 19:16:29 UTC 2016


Hi Jon,

That looks good.

There's a log message that might need updating also? "initSize" => 
"initThreshold"?
Line 1577:
       log_trace(gc, metaspace)("    shrinking:  initSize: %.1fK  
maximum_desired_capacity: %.1fK",
                                MetaspaceSize / (double) K, 
maximum_desired_capacity / (double) K);

  - Derek

On 3/15/16 12:56 PM, Jon Masamitsu wrote:
> https://bugs.openjdk.java.net/browse/JDK-8151845
>
> Change the description for MetaspaceSize in globals.hpp thus
>
> -          "Initial size of Metaspaces (in 
> bytes)")                          \
> +          "Initial threshold (in bytes) at which a garbage collection 
> "     \
> +          "is done to reduce Metaspace 
> usage")                              \
>
> Garbage collections will be done specifically to recover metadata
> (the GC finds dead classloaders and identifies metadata associated
> with the classloaders that is no longer used).  Triggering a GC for
> metadata recovery is done if the amount of metadata in use exceeds
> a threshold that is dynamically adjusted (threshold is raised or lowered
> depending on the amount of Metaspace made available for new metadata
> allocations).  MetaspaceSize is the initial threshold.
>
> http://cr.openjdk.java.net/~jmasa/8141845/webrev.00/
>
> I am very open to suggestions for a better description.
>
> My apologies to Yasumasa Suenaga for not settling this issue
> when he raised it almost 2 years ago.
>
> http://mail.openjdk.java.net/pipermail/hotspot-gc-dev/2014-April/009916.html 
>
>
> Jon
>
>



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