RFR (M): 8212206: Refactor AdaptiveSizePolicy to separate out code related to GC overhead

Jiangli Zhou jianglizhou at google.com
Tue Mar 5 15:53:05 UTC 2019


Hi Man,

The comment change looks ok to me.

Thanks and regards,
Jiangli

On Mon, Mar 4, 2019 at 6:20 PM Man Cao <manc at google.com> wrote:

> After offline discussion with Jiangli, we think it is better to just
> remove this comment block.
> The reason is that full GCs due to metaspace expansion will not take the
> code path to execute AdaptiveSizePolicy::check_gc_overhead_limit(), because
> of the check for AdaptiveSizePolicy::should_update_promo_stats().
>
> New webrev: https://cr.openjdk.java.net/~manc/8212206/webrev.05/
>
> -Man
>
>
> On Mon, Mar 4, 2019 at 2:41 PM Man Cao <manc at google.com> wrote:
>
>> Thanks for taking a look, Jiangli. I renamed "permanent gen" to
>> "metaspace".
>> I double checked that currently full GCs due to metaspace expansion will
>> not affect the calculation of GC overhead .
>>
>> New webrev: https://cr.openjdk.java.net/~manc/8212206/webrev.04/
>>
>> -Man
>>
>>
>> On Sun, Mar 3, 2019 at 11:48 AM Jiangli Zhou <jianglizhou at google.com>
>> wrote:
>>
>>> Hi Man,
>>>
>>> As both Thomas and Per seemed to be okay with the refactoring, you
>>> probably had sufficient approval already.
>>>
>>> The following comment in adaptiveSizePolicy.cpp seems to be outdated.
>>> The comment predates the PermGen removal. It's probably a good idea to also
>>> cleanup the comment as part of your refactoring change.
>>>
>>>  281     // Note that the gc time limit test only works for the collections 282     // of the young gen + tenured gen and not for collections of the 283     // permanent gen.  That is because the calculation of the space 284     // freed by the collection is the free space in the young gen + 285     // tenured gen.
>>>
>>> Thanks and regards,
>>>
>>> Jiangli
>>>
>>>
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