Re: [RFC PATCH 00/57] mm/collapse: rebuild collapse on migration primitives

[Kiryl Shutsemau]

On Mon, Sep 14, 2026 at 04:54:06PM +0200, David Hildenbrand (Arm) wrote:
> I saw that you started sending out cleanups, good. :)

Right. I have few more cleanup ideas in the queue, before substantive
changes.

> Nobody can really review 39 patches of RFC.
> 
> Often it's more helpful to propose an overall design idea, and then discuss if
> and how to get there.

Fair.

The overall design one-pager is in comment in mm/collapse.c in 07/57.

I can pull it out, expand and post as RFD if it helpful.

> > Do we want to find file collapse candidates by walking the virtual
> > address space at all?
> 
> In guest_memfd, we recently discussed that we actually would want a mechanism to
> collapse even without walking the VA space .... but maybe guest_memfd is just
> too special, not sure.
> 
> You still need a mmap to identify the candidate file IIRC.

At the moment, yes. But it is not the only option. We can start from
walking inodes for superblocks that opted in for collapse.

> The churn is always the problem.
> 
> Small, controlled increments please.

Ack.

Just to re-iterate what I told Lorenzo: I never intended to push this as
one big patchset. The purpose of the RFC was to demonstrate the end
state I pursue. I am flexible on how we get there.

-- 
  Kiryl Shutsemau / Kirill A. Shutemov