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

[Erik Helin]

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":

http://cr.openjdk.java.net/~ehelin/8036696/webrev.01/

What do you think?

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
>>>
>