Re: [RFC PATCH v1 00/10] mm: Introduce and use folio_owner_ops

[Jason Gunthorpe <jgg@nvidia.com>]

On Tue, Nov 12, 2024 at 10:10:06AM +0100, David Hildenbrand wrote:
> On 12.11.24 06:26, Matthew Wilcox wrote:
> > On Mon, Nov 11, 2024 at 08:26:54AM +0000, Fuad Tabba wrote:
> > > Thanks for your comments Jason, and for clarifying my cover letter
> > > David. I think David has covered everything, and I'll make sure to
> > > clarify this in the cover letter when I respin.
> > 
> > I don't want you to respin.  I think this is a bad idea.
> 
> I'm hoping you'll find some more time to explain what exactly you don't
> like, because this series only refactors what we already have.
> 
> I enjoy seeing the special casing (especially hugetlb) gone from mm/swap.c.
> 
> I don't particularly enjoy overlaying folio->lru, primarily because we have
> to temporarily "evacuate" it when someone wants to make use of folio->lru
> (e.g., hugetlb isolation). So it's not completely "sticky", at least for
> hugetlb.

This is really the worst part of it though

And, IMHO, seems like overkill. We have only a handful of cases -
maybe we shouldn't be trying to get to full generality but just handle
a couple of cases directly? I don't really think it is such a bad
thing to have an if ladder on the free path if we have only a couple
things. Certainly it looks good instead of doing overlaying tricks.

Also how does this translate to Matthew's memdesc world? 

Jason