On 27/02/14 18:23, Alex Thorlton wrote: > As Christian pointed out, the recent 'Revert "thp: make MADV_HUGEPAGE > check for mm->def_flags"' breaks qemu, it does QEMU_MADV_HUGEPAGE for > all kvm pages but this doesn't work after s390_enable_sie/thp_split_mm. > > Paolo suggested that instead of failing on the call to madvise, we > simply ignore the call (return 0). > > Reported-by: Christian Borntraeger <[email protected]> > Suggested-by: Paolo Bonzini <[email protected]> > Suggested-by: Oleg Nesterov <[email protected]> > Signed-off-by: Alex Thorlton <[email protected]> > Cc: Gerald Schaefer <[email protected]> > Cc: Martin Schwidefsky <[email protected]> > Cc: Heiko Carstens <[email protected]> > Cc: Christian Borntraeger <[email protected]> > Cc: Andrew Morton <[email protected]> > Cc: Paolo Bonzini <[email protected]> > Cc: "Kirill A. Shutemov" <[email protected]> > Cc: Mel Gorman <[email protected]> > Cc: Rik van Riel <[email protected]> > Cc: Ingo Molnar <[email protected]> > Cc: Peter Zijlstra <[email protected]> > Cc: Andrea Arcangeli <[email protected]> > Cc: Oleg Nesterov <[email protected]> > Cc: "Eric W. Biederman" <[email protected]> > Cc: Alexander Viro <[email protected]> > Cc: [email protected] > Cc: [email protected] > Cc: [email protected] > Cc: [email protected] > Cc: [email protected] > > --- > mm/huge_memory.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index a4310a5..61d234d 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -1970,6 +1970,15 @@ int hugepage_madvise(struct vm_area_struct *vma, > { > switch (advice) { > case MADV_HUGEPAGE: > +#ifdef CONFIG_S390 > + /* > + * qemu blindly sets MADV_HUGEPAGE on all allocations, but s390 > + * can't handle this properly after s390_enable_sie, so we > simply > + * ignore the madvise to prevent qemu from causing a SIGSEGV. > + */ > + if (mm_has_pgste(vma->vm_mm)) > + return 0; > +#endif > /* > * Be somewhat over-protective like KSM for now! > */ >
Tested-by: Christian Borntraeger <[email protected]> -- 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/
