RFR: 8243315: ParallelScavengeHeap::initialize() passes GenAlignment as page size to os::trace_page_sizes instead of actual page size

[Stefan Johansson]

On Thu, 3 Dec 2020 20:24:23 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

>> You are correct that explicit huge pages are pinned and of course there might be situations where it would be beneficial to do the stitching, but I think the maintenance cost will be significantly higher. It sound like you would prefer a simpler model as well and int would certainly be interesting to see if there are any problems connected to getting rid of the mixed mappings we have today.
>> 
>> I also agree that we should do better book keeping since it is so hard to get the information later on.
>
> Hi guys,
> 
> gentle ping. I know we are all busy with the impending code freeze :)
> 
> I am fine with removing the ability to reserve space with multiple page sizes. But that is something I cannot drive - probably someone at Oracle should, since it has repercussions for GC and for backward compatibility. Might also take a bit longer.
> 
> Meanwhile, we still have the new ReservedSpace::actual_page_size(), which is subtly broken and will be more so once JDK-8234930 is implemented. IIUC you did not like the proposal of making reserve_space_special() return information about the reserved page sizes. That's totally fine for me, but have we decided on how to deal with this instead?
> 
> Cheers, Thomas

Hi Thomas,

I just filed [JDK-8257757](https://bugs.openjdk.java.net/browse/JDK-8257757) to keep track of this, feel free to add information to it. Let's work together to try to improve this.

Cheers,
Stefan

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PR: https://git.openjdk.java.net/jdk/pull/1161