On Tue, Oct 28, 2025 at 05:29:59PM +0000, Lorenzo Stoakes wrote: > > > > If we want to avoid the implicit capping, I think there are the following > > possible approaches > > > > (1) Tolerate creep for now, maybe warning if the user configures it. > > I mean this seems a viable option if there is pressure to land this series > before we have a viable uAPI for configuring this. > > A part of me thinks we shouldn't rush series in for that reason though and > should require that we have a proper control here. > > But I guess this approach is the least-worst as it leaves us with the most > options moving forwards. > > > (2) Avoid creep by counting zero-filled pages towards none_or_zero. > > Would this really make all that much difference? > > > (3) Have separate toggles for each THP size. Doesn't quite solve the > > problem, only shifts it. > > Yeah I did wonder about this as an alternative solution. But of course it then > makes it vague what the parent values means in respect of the individual > levels, > unless we have an 'inherit' mode there too (possible). > > It's going to be confusing though as max_ptes_none sits at the root > khugepaged/ > level and I don't think any other parameter from khugepaged/ is exposed at > individual page size levels. > > And of course doing this means we
Oops didn't finish the thought! Here it is: And of course this means we continue to propagate this max_ptes_none concept only now in more places which is yuck. Unless you meant putting something other than max_ptes_none at different levels? Cheers, Lorenzo
