From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964833Ab2HWRTH (ORCPT ); Thu, 23 Aug 2012 13:19:07 -0400 Received: from e06smtp11.uk.ibm.com ([195.75.94.107]:45603 "EHLO e06smtp11.uk.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755128Ab2HWRTC (ORCPT ); Thu, 23 Aug 2012 13:19:02 -0400 Message-Id: <20120823171854.580076595@de.ibm.com> User-Agent: quilt/0.47-1 Date: Thu, 23 Aug 2012 19:17:36 +0200 From: Gerald Schaefer To: akpm@linux-foundation.org, aarcange@redhat.com, linux-mm@kvack.org, ak@linux.intel.com, hughd@google.com Cc: linux-kernel@vger.kernel.org, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, gerald.schaefer@de.ibm.com Subject: [RFC patch 3/7] thp: make MADV_HUGEPAGE check for mm->def_flags References: <20120823171733.595087166@de.ibm.com> Content-Disposition: inline; filename=linux-3.5-thp-madvise.patch x-cbid: 12082317-5024-0000-0000-000003955DB7 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- 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; *vm_flags &= ~VM_NOHUGEPAGE; *vm_flags |= VM_HUGEPAGE; /*