Messages in this thread Patch in this message | | | Date | Wed, 22 Jan 2014 12:16:43 -0800 (PST) | From | Hugh Dickins <> | Subject | Re: [PATCH 2/2] mm: thp: kill the bogus ->def_flags check in hugepage_madvise() |
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On Wed, 22 Jan 2014, Oleg Nesterov wrote:
> hugepage_madvise() checks "mm->def_flags & VM_NOHUGEPAGE" but > this can be never true, currently mm->def_flags can only have > VM_LOCKED.
But line 1087 of arch/s390/mm/pgtable.c says mm->def_flags |= VM_NOHUGEPAGE; from 3eabaee998c787e7e1565574821652548f7fc003 "KVM: s390: allow sie enablement for multi-threaded programs".
Hugh
> > And otoh we might want to add VM_NOHUGEPAGE into ->def_flags > but override it in vma->vm_flags via madvise(MADV_HUGEPAGE). > > Signed-off-by: Oleg Nesterov <oleg@redhat.com> > --- > mm/huge_memory.c | 2 -- > 1 files changed, 0 insertions(+), 2 deletions(-) > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index bccd5a6..e8b656c 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -1941,8 +1941,6 @@ int hugepage_madvise(struct vm_area_struct *vma, > */ > if (*vm_flags & (VM_HUGEPAGE | VM_NO_THP)) > return -EINVAL; > - if (mm->def_flags & VM_NOHUGEPAGE) > - return -EINVAL; > *vm_flags &= ~VM_NOHUGEPAGE; > *vm_flags |= VM_HUGEPAGE; > /* > -- > 1.5.5.1 > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ >
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