On 27.06.2018 15:55, 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 af0a87eeede0..c691b9d9d223 100644 > --- a/arch/s390/mm/gmap.c > +++ b/arch/s390/mm/gmap.c > @@ -723,6 +723,9 @@ 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 */ Can you add why we don't do that? > + if (vma && is_vm_hugetlb_page(vma)) > + continue; > size = min(to - gaddr, PMD_SIZE - (gaddr & ~PMD_MASK)); > zap_page_range(vma, vmaddr, size); > } > Apart from that Reviewed-by: David Hildenbrand <david@xxxxxxxxxx> -- Thanks, David / dhildenb
