RFR: 8036696: Add metaspace gc threshold to metaspace summary trace event

[Jon Masamitsu]

On 3/12/2014 5:24 AM, Erik Helin wrote:
> Jon,
>
> based on our discussion, I've changed the code to use the variable 
> name _capacity_until_GC and the event to use the name "gcThreshold":

Thanks.

>
> http://cr.openjdk.java.net/~ehelin/8036696/webrev.01/
>
> What do you think?

Looks good.  Reviewed.

Jon

>
> Thanks,
> Erik
>
> On 2014-03-10 19:59, Jon Masamitsu wrote:
>>
>> On 3/10/14 2:22 AM, Erik Helin wrote:
>>> Hi Jon,
>>>
>>> thanks for having a look at the patch!
>>>
>>> On 2014-03-06 23:30, Jon Masamitsu wrote:
>>>> Erik,
>>>>
>>>> Why the choice of the variable name _gc_threshold instead of the
>>>> variable name _capacity_until_gc (the same variable name as
>>>> in Metaspace)?  Using the label "GC Threshold" seems ok.  I
>>>> can understand not making that title too geeky.
>>>
>>> Since the the meaning of the word "capacity" has caused me (us?) some
>>> problems in the metaspace code (is it words/bytes? is it
>>> committed/used or something else?), I believe it is better to use that
>>> does not imply to "what" the high-water mark is compared. The name
>>> _capacity_until_gc implies that we compare the value to some kind of
>>> capacity, whereas the name gc_threshold just states that this is a
>>> some kind of limit.
>>>
>>> Ideally, I would like to see us rename MetaspaceGC::_capacity_until_gc
>>> to MetaspaceGC::_gc_threshold, but that is another patch.
>>>
>>> What do you think?
>>
>> Can you correct _capactiy_until_gc to a more  correct and precise name?
>> Or at least change _gc_threshold to a more correct and precise name
>> and make _capacity_until_gc follow later.
>>
>> _gc_threshold seems to me has all the ambiguities of _capacity_until_gc.
>>
>> Jon
>>
>>>
>>> Thanks,
>>> Erik
>>>
>>>> Otherwise, looks good.
>>>>
>>>> Jon
>>>>
>>>> On 3/6/2014 12:07 AM, Erik Helin wrote:
>>>>> Hi all,
>>>>>
>>>>> this change add the metaspace GC threshold
>>>>> (Metaspace::_capacity_until_gc) to the trace event
>>>>> vm/gc/heap/metaspace_summary.
>>>>>
>>>>> Enhancement:
>>>>> https://bugs.openjdk.java.net/browse/JDK-8036696
>>>>>
>>>>> Webrev:
>>>>> http://cr.openjdk.java.net/~ehelin/8036696/webrev.00/
>>>>>
>>>>> Testing:
>>>>> - JFR JTREG tests
>>>>> - JPRT
>>>>>
>>>>> Thanks,
>>>>> Erik
>>>>
>>