On 13 Aug 2025, at 9:55, Usama Arif 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> > --- > fs/proc/task_mmu.c | 4 ++-- > include/linux/huge_mm.h | 30 ++++++++++++++++++------------ > mm/huge_memory.c | 8 ++++---- > mm/khugepaged.c | 17 ++++++++--------- > mm/memory.c | 14 ++++++-------- > 5 files changed, 38 insertions(+), 35 deletions(-) > Reviewed-by: Zi Yan <ziy@xxxxxxxxxx> Best Regards, Yan, Zi
