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

[David Hildenbrand <david@redhat.com>]

On 21.05.25 19:32, Johannes Weiner wrote:
> 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.

As stated elsewhere (e.g., THP cabal yesterday): mctrl() or sth like 
that might be better.

... or anything else that doesn't (ab)use the "advise" terminology in an 
interface that will not only consume advises.

>>
>> 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.

Same here. I am not 100% sure process_madvise() is really the right 
thing to extend, but I do enjoy the SET_DEFAULT_EXEC option. I am also 
not a big fan of prctl() ...

-- 
Cheers,

David / dhildenb