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

[Thomas Stuefe]

On Wed, 25 Nov 2020 14:40:52 GMT, Stefan Johansson <sjohanss at openjdk.org> wrote:

> So Thomas in what cases do we need the `ReservedSpace` to be able to handle multiple page-sizes? A simpler approach would be to aim for only having one page size per `ReservedSpace`. For example, in G1 it would be problematic or at least inefficient to have multiple page sizes per mapping.

Happens if you reserve a space with a size not aligned to the underlying large page size. See reserve_memory_special_huge_tlbfs_mixed() on Linux. In that case, we try to be smart and fill in the ends with small pages rather than failing.

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