On Mon, Sep 15, 2025 at 12:44:34PM +0200, David Hildenbrand wrote: > > > > Mapping that to actual THP sizes (#pages in a thp) on an arch will be > > > > easy. > > > > > > And at different mTHP levels too right? > > > > > > > Another point here, since we have to keep: > > > > /sys/kernel/mm/transparent_hugepage/khugepaged/max_ptes_none > > > > Around, and users will try to set values there, presumably we will now add: > > > > /sys/kernel/mm/transparent_hugepage/khugepaged/eagerness > > > > How will we map <-> the two tunables? > > Well, the easy case if someone updates eagerness, then we simply et it to > whatever magic value we compute and document. > > The other direction is more problematic, likely we'll simply warn and do > something reasonable (map it to whatever eagerness scale is closest or > simply indicate it as "-1" -- user intervened or sth like that)
I don't love the idea of a -1 situation, as that's going to create some confusion. I'd really rather we just say out and out 'the kernel decides this based on eagerness'. So either warn or have some method to reverse-engineer what the closest value might be. Or perhaps just accept 0/511 there and map to eagerness min/max + if non-0/511 warn? > > -- > Cheers > > David / dhildenb > Cheers, Lorenzo
