Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751942AbbKJTzF (ORCPT ); Tue, 10 Nov 2015 14:55:05 -0500 Received: from aserp1040.oracle.com ([141.146.126.69]:36536 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750906AbbKJTye (ORCPT ); Tue, 10 Nov 2015 14:54:34 -0500 Subject: Re: [PATCH] xen/gntdev: Grant maps should not be subject to NUMA balancing To: Konrad Rzeszutek Wilk References: <1447183364-2959-1-git-send-email-boris.ostrovsky@oracle.com> <20151110193644.GA32257@char.us.oracle.com> Cc: david.vrabel@citrix.com, xen-devel@lists.xen.org, linux-kernel@vger.kernel.org From: Boris Ostrovsky Message-ID: <56424B77.70106@oracle.com> Date: Tue, 10 Nov 2015 14:54:31 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.1.0 MIME-Version: 1.0 In-Reply-To: <20151110193644.GA32257@char.us.oracle.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Source-IP: aserv0022.oracle.com [141.146.126.234] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1703 Lines: 53 On 11/10/2015 02:36 PM, Konrad Rzeszutek Wilk wrote: > On Tue, Nov 10, 2015 at 02:22:44PM -0500, Boris Ostrovsky wrote: >> Doing so will cause the grant to be unmapped and then, during >> fault handling, the fault to be mistakenly treated as NUMA hint >> fault. >> >> In addition, even if we those maps could partcipate in NUMA >> balancing it wouldn't provide any benefit since we wouldn't be >> able to determine physical page's node (even if/when VNUMA is >> implemented). >> >> Marking grant maps' VMAs as VM_IO will exclude them from being >> part of NUMA balancing. >> > Should this be 'cc:stable@vger.kernel.org' ? This bug becomes a real problem with 4.4, now that NUMA balancing is on by default. But we should probably include it in stable too. I'll resubmit it then with CC tag. -boris > > >> Signed-off-by: Boris Ostrovsky >> --- >> drivers/xen/gntdev.c | 2 +- >> 1 files changed, 1 insertions(+), 1 deletions(-) >> >> diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c >> index 67b9163..bf312df 100644 >> --- a/drivers/xen/gntdev.c >> +++ b/drivers/xen/gntdev.c >> @@ -802,7 +802,7 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma) >> >> vma->vm_ops = &gntdev_vmops; >> >> - vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP; >> + vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP | VM_IO; >> >> if (use_ptemod) >> vma->vm_flags |= VM_DONTCOPY; >> -- >> 1.7.1 >> -- 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/