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

Jon Masamitsu jon.masamitsu at oracle.com
Wed Mar 16 21:55:17 UTC 2016

On 03/16/2016 12:16 PM, Derek White wrote:

Hi Jon,

That looks good. There's a log message that might need updating also? "initSize" => "initThreshold"?

Thanks for catching that. Fixed.

Line 1577: logtrace(gc, metaspace)(" shrinking: initSize: %.1fK maximumdesiredcapacity: %.1fK", MetaspaceSize / (double) K, maximumdesiredcapacity / (double) K);

And thanks for the review.

Jon

- 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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