Il 27/02/2014 18:23, Alex Thorlton ha scritto:
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 <borntrae...@de.ibm.com> Suggested-by: Paolo Bonzini <pbonz...@redhat.com> Suggested-by: Oleg Nesterov <o...@redhat.com> Signed-off-by: Alex Thorlton <athorl...@sgi.com> Cc: Gerald Schaefer <gerald.schae...@de.ibm.com> Cc: Martin Schwidefsky <schwidef...@de.ibm.com> Cc: Heiko Carstens <heiko.carst...@de.ibm.com> Cc: Christian Borntraeger <borntrae...@de.ibm.com> Cc: Andrew Morton <a...@linux-foundation.org> Cc: Paolo Bonzini <pbonz...@redhat.com> Cc: "Kirill A. Shutemov" <kirill.shute...@linux.intel.com> Cc: Mel Gorman <mgor...@suse.de> Cc: Rik van Riel <r...@redhat.com> Cc: Ingo Molnar <mi...@kernel.org> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Andrea Arcangeli <aarca...@redhat.com> Cc: Oleg Nesterov <o...@redhat.com> Cc: "Eric W. Biederman" <ebied...@xmission.com> Cc: Alexander Viro <v...@zeniv.linux.org.uk> Cc: linux...@de.ibm.com Cc: linux-s...@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux...@kvack.org Cc: linux-...@vger.kernel.org --- 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! */
Acked-by: Paolo Bonzini <pbonz...@redhat.com> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
