RFR: 8249676: [REDO] G1 incorrectly limiting young gen size when using the reserve can result in repeated full gcs

[Kim Barrett]

> On Sep 14, 2020, at 5:11 AM, Thomas Schatzl <thomas.schatzl at oracle.com> wrote:
> On 13.09.20 03:41, Kim Barrett wrote:
>> src/hotspot/share/gc/g1/g1Policy.cpp
>> 1364   if (reclaimable_percent <= threshold) {
>> The two logging messages that follow are rather excessively long.
>> And if they were formatted differently it might make it more obvious they
>> are identical except for the parenthetical part of the message.  (Or at
>> least I *think* they are; not so easy to compare by eye across horizongal
>> scrolling or wrapping.)
>> (I looked at combining them; not sure it's worthwhile.)
> 
> Fixed them a bit, but did not combine the messages. From starting on this I saw that it made the code more complicated than worth.

Agreed that the complications aren’t worth it.

> I rebased the changes in the PR for easier testing (tier1,2 running). The webrev did not work before and does not now (https://bugs.openjdk.java.net/browse/SKARA-595), so it's probably best again to look at the diff in github at
> 
> https://github.com/openjdk/jdk/pull/108/commits/ff64ae374001706958062750b5144d2c61417a69

Thanks.  I hope the webrev problems get fixed soon.