Re: [PATCH] kpageflags: respect folio head-page flag placement

[Gregory Price]

On Wed, Oct 25, 2023 at 09:34:15PM -0400, Rik van Riel wrote:
> On Wed, 2023-10-25 at 16:12 -0400, Gregory Price wrote:
> >         u |= kpf_copy_bit(k, KPF_SWAPBACKED,    PG_swapbacked);
> > 
> 
> Aren't PG_locked, PG_reclaim, and PG_swapbacked also maintained only on
> the folio/head?
> 
> Would it make sense to convert those over as well?
> 

I see them registered as PF_NO_TAIL in include/linux/page-flags.h

Certainly i think there are other updates that are likely needed, but
I wasn't quite sure how to handle ONLY_HEAD and NO_TAIL and other
conditionals.  Should the bits always be 0 or should it refer to HEAD?

Just not sure at the moment.

~Gregory