On 14/08/2025 04:07, Yafang Shao wrote: > On Wed, Aug 13, 2025 at 9:57 PM Usama Arif <usamaarif642@xxxxxxxxx> wrote: >> >> From: David Hildenbrand <david@xxxxxxxxxx> >> >> When determining which THP orders are eligible for a VMA mapping, >> we have previously specified tva_flags, however it turns out it is >> really not necessary to treat these as flags. >> >> Rather, we distinguish between distinct modes. >> >> The only case where we previously combined flags was with >> TVA_ENFORCE_SYSFS, but we can avoid this by observing that this >> is the default, except for MADV_COLLAPSE or an edge cases in >> collapse_pte_mapped_thp() and hugepage_vma_revalidate(), and >> adding a mode specifically for this case - TVA_FORCED_COLLAPSE. >> >> We have: >> * smaps handling for showing "THPeligible" >> * Pagefault handling >> * khugepaged handling >> * Forced collapse handling: primarily MADV_COLLAPSE, but also for >> an edge case in collapse_pte_mapped_thp() >> >> Disregarding the edge cases, we only want to ignore sysfs settings only >> when we are forcing a collapse through MADV_COLLAPSE, otherwise we >> want to enforce it, hence this patch does the following flag to enum >> conversions: >> >> * TVA_SMAPS | TVA_ENFORCE_SYSFS -> TVA_SMAPS >> * TVA_IN_PF | TVA_ENFORCE_SYSFS -> TVA_PAGEFAULT >> * TVA_ENFORCE_SYSFS -> TVA_KHUGEPAGED >> * 0 -> TVA_FORCED_COLLAPSE >> >> With this change, we immediately know if we are in the forced collapse >> case, which will be valuable next. >> >> Signed-off-by: David Hildenbrand <david@xxxxxxxxxx> >> Acked-by: Usama Arif <usamaarif642@xxxxxxxxx> >> Signed-off-by: Usama Arif <usamaarif642@xxxxxxxxx> >> Reviewed-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx> >> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx> > > Acked-by: Yafang Shao <laoar.shao@xxxxxxxxx> > > Hello Usama, > > This change is also required by my BPF-based THP order selection > series [0]. Since this patch appears to be independent of the series, > could we merge it first into mm-new or mm-everything if the series > itself won't be merged shortly? > > Link: https://lwn.net/Articles/1031829/ [0] > Thanks for reviewing! All of the patches in the series have several acks/reviews. Only a small change might be required in selftest, so hopefully the next revision is the last one. Andrew - would it be ok to start including this entire series in the mm-new now? Thanks!
