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

Derek White derek.white at oracle.com
Fri Mar 18 20:15:00 UTC 2016


Looks even better!

  - Derek

On 3/16/16 6:12 PM, Jon Masamitsu wrote:
> I updated the webrev to include Derek's suggestion and seem to have
> clobbered the first version of the webrev in the process. Fortunately,
> the changes is so small (hint, hint to potential reviewers) that it 
> matters
> very little.
>
> http://cr.openjdk.java.net/~jmasa/8151845/webrev.01/
>
> Jon
>
> 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"?
>> 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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