On 14/07/2026 17:16, Vishal Moola wrote:
On Tue, Jul 14, 2026 at 03:04:03PM +0100, Kevin Brodsky wrote:
quoted
As a step towards removing pagetable ctor/dtor calls for kernel
mm's, move the page type updates from the ctor/dtor to
pagetable_{alloc,free}.
Thanks for doing this patchset.
Thanks for suggesting it :) It's turning out to be quite a bit more
involved than I expected though! (There are multiple cases where we call
the ctor/dtor without using pagetable_{alloc,free}, see my reply to the
cover letter.)
We should switch over from __folio_set_pgtable() to __SetPagePgtable()
in this patch. Ptdescs and folios should be treated as distinctly
independent of each other.
I sure remember the previous discussion, but my reading of your comments
[1] is that we cannot really change this as long as pagetable_alloc()
can be called with order > 0, right? Multiple archs still rely on that.
Eventually, we want to replace the memcg accounting as well, but
there's no existing API for that right now. Lets leave that as is for
now; this patchset is big enough already ;)
Yep, looks like there was an attempt to improve this but it had to be
reverted [2].
- Kevin
[1] https://lore.kernel.org/all/aha321ndGSdReBJR@fedora/ (local)
[2]
https://lore.kernel.org/all/20260225002434.2953895-1-axelrasmussen@google.com/ (local)