On 13.12.2017 13:53, Janosch Frank wrote: > From: Dominik Dingel <dingel@xxxxxxxxxxxxxxxxxx> > > Guests backed by huge pages could theoretically free unused pages via > the diagnose 10 instruction. We currently don't allow that, so we > don't have to refault it once it's needed again. > > Signed-off-by: Dominik Dingel <dingel@xxxxxxxxxxxxxxxxxx> > Reviewed-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx> > --- > arch/s390/mm/gmap.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c > index aceaeb5..056acfc 100644 > --- a/arch/s390/mm/gmap.c > +++ b/arch/s390/mm/gmap.c > @@ -695,6 +695,9 @@ void gmap_discard(struct gmap *gmap, unsigned long from, unsigned long to) > vmaddr |= gaddr & ~PMD_MASK; > /* Find vma in the parent mm */ > vma = find_vma(gmap->mm, vmaddr); > + /* We do not discard pages that are backed by hugetlbfs */ > + if (vma && is_vm_hugetlb_page(vma)) > + continue; > size = min(to - gaddr, PMD_SIZE - (gaddr & ~PMD_MASK)); > zap_page_range(vma, vmaddr, size); > } > This check does not care about split huge pages, correct? (because we're checking the VMA?) -- Thanks, David / dhildenb
