RFR: 8309065: Move the logic to determine archive heap location from CDS to G1 GC [v2]

[Thomas Schatzl]

On Fri, 2 Jun 2023 03:36:38 GMT, Ioi Lam <iklam at openjdk.org> wrote:

> Hi Ashutosh,
> 
> You are right that in the existing code, although filemap.cpp finds out where the requested range is, it doesn't actually pass that to G1. It just requests G1 to reserve a range at the end of the runtime heap. So your PR preserves this behavior.
> 
> I think Thomas's point is, the requested range should be passed to the `alloc_archive_regions()` API, even though the collector may simply ignore it.

Exactly, sorry if I wasn't clear enough.

> 
> In the past, the archive G1 regions were not movable, so it was preferable to put them at the end of the heap, even though that might cause relocation. Now that the archive regions are just regular "old" regions, which can move, it may be preferable to reserve them at the requested range.
> 
> BTW, perhaps `alloc_archive_regions()` should be renamed to `alloc_archive_range()` going forward. The plural form of "regions" sounds odd for non-region based collectors.

+1

Thanks,
  Thomas

-------------

PR Comment: https://git.openjdk.org/jdk/pull/14208#issuecomment-1573282235