Re: [RFC PATCH 0/5] add process_madvise() flags to modify behaviour

[Johannes Weiner <hannes@cmpxchg.org>]

On Wed, May 21, 2025 at 05:21:19AM +0100, Lorenzo Stoakes wrote:
> So, something Liam mentioned off-list was the beautifully named
> 'mmadvise()'. Idea being that we have a system call _explicitly for_
> mm-wide modifications.
> 
> With Barry's series doing a prctl() for something similar, and a whole host
> of mm->flags existing for modifying behaviour, it would seem a natural fit.

That's an interesting idea.

So we'd have THP policies and Barry's FADE_ON_DEATH to start; and it
might also be a good fit for the coredump stuff and ksm if we wanted
to incorporate them into that (although it would duplicate the
existing proc/prctl knobs). The other MMF_s are internal AFAICS.

I think my main concern would be making something very generic and
versatile without having sufficiently broad/popular usecases for it.

But no strong feelings either way. Like I said, I don't have a strong
dislike for prctl(), but this idea would obviously be cleaner if we
think there is enough of a demand for a new syscall.

> I guess let me work that up so we can see how that looks?

I think it's worth exploring!