RFR: 8228991: Obsolete -XX:UseAdaptiveGCBoundary

[Kim Barrett]

> On Apr 15, 2020, at 11:23 AM, Thomas Schatzl <thomas.schatzl at oracle.com> wrote:
> On 15.04.20 16:16, Kim Barrett wrote:
>>> On Apr 15, 2020, at 4:49 AM, Thomas Schatzl <thomas.schatzl at oracle.com> wrote:
>>> Found some outdated comments:
>> StefanK found some more unnecessary stuff that I’d missed.  In particular, AdjoiningGenerations
>> and AdjoiningVirtualSpaces can be removed with a small amount of additional changes.
>> [...]
>>> - comment in psYoungGen::gen_size_limit() outdated
>> Looking at this and similar function in PSOldGen, I think they are now duplicative of other functions
>> in the corresponding APIs (PSYoungGen::max_size() and PSOldGen::Max_gen_size()).  More stuff
>> I missed.  Stefen didn’t do anything with these in his proposed followup cleanup either.   In order to
>> minimize the risk of causing merge collisions with his existing webrev, I think I want to avoid doing
>> anything significant in this area with this change. I’ve changed the description though, which now
>> matches that of PSYoungGen::max_size().
> 
> I considered pointing that out, but in the end refrained from commenting further. Okay for deferring further changes to this.

I’ve filed JDK-8242901 to followup on this.

> 
>>>> Note: Unable to test nvdimm usage since we don't have any machines
>>>> with that configuration.
>>> 
>>> The only related option Parallel GC supports is AllocateHeapAt, and you can pass it any arbitrary file name. I.e. you could test it by specifying a file name in a memory backed directory.
>>> 
>>> Since the impact is only memory reservation, I do not expect a difference though.
>> OK, I’ll figure out how to run them that way.
>> New webrevs:
>> full: https://cr.openjdk.java.net/~kbarrett/8228991/open.01/
>> incr: https://cr.openjdk.java.net/~kbarrett/8228991/open.01.inc/
> 
> Looks good.

Thanks.