On Sat, 25 Aug 2012 20:47:37 +0800 Hillf Danton <[email protected]> wrote:
> On Fri, Aug 24, 2012 at 1:17 AM, Gerald Schaefer > <[email protected]> wrote: > > This adds a check to hugepage_madvise(), to refuse MADV_HUGEPAGE > > if VM_NOHUGEPAGE is set in mm->def_flags. On System z, the VM_NOHUGEPAGE > > flag will be set in mm->def_flags for kvm processes, to prevent any > > future thp mappings. In order to also prevent MADV_HUGEPAGE on such an > > mm, hugepage_madvise() should check mm->def_flags. > > > > Signed-off-by: Gerald Schaefer <[email protected]> > > --- > > mm/huge_memory.c | 4 ++++ > > 1 file changed, 4 insertions(+) > > > > --- a/mm/huge_memory.c > > +++ b/mm/huge_memory.c > > @@ -1464,6 +1464,8 @@ out: > > int hugepage_madvise(struct vm_area_struct *vma, > > unsigned long *vm_flags, int advice) > > { > > + struct mm_struct *mm = vma->vm_mm; > > + > > switch (advice) { > > case MADV_HUGEPAGE: > > /* > > @@ -1471,6 +1473,8 @@ int hugepage_madvise(struct vm_area_stru > > */ > > if (*vm_flags & (VM_HUGEPAGE | VM_NO_THP)) > > return -EINVAL; > > + if (mm->def_flags & VM_NOHUGEPAGE) > > + return -EINVAL; > > Looks ifdefinery needed for s390 to wrap the added check, and > a brief comment? Hmm, architecture #ifdefs in common code are ugly. I'd rather keep the check even if it is redundant right now for other architectures than s390. It is not a performance critical path, and there may be other users of that in the future. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
