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

Man Cao manc at google.com
Tue Mar 5 02:20:03 UTC 2019


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 The following comment in adaptiveSizePolicy.cpp seems to be outdated.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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