Re: [PATCH v5 3/5] mm: LARGE_ANON_FOLIO for improved performance

From: Matthew Wilcox
Date: Thu Aug 31 2023 - 08:29:49 EST


On Thu, Aug 31, 2023 at 09:57:46AM +0200, David Hildenbrand wrote:
> As raised in another mail, we can then discuss
> * how we want to call this feature (transparent large pages? there is
> the concern that "THP" might confuse users. Maybe we can consider
> "large" the more generic version and "huge" only PMD-size, TBD)
> * how to expose it in stats towards the user (e.g., /proc/meminfo)
> * which minimal toggles we want
>
> I think there *really* has to be a way to disable it for a running system,
> otherwise no distro will dare pulling it in, even after we figured out the
> other stuff.
>
> Note that for the pagecache, large folios can be disabled and distributions
> are actively making use of that.

You can't. Well, you can for shmem/tmpfs, but you have to edit the
source code or disable CONFIG_TRANSPARENT_HUGEPAGE to disable it for XFS.