From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753857AbcG1ISm (ORCPT ); Thu, 28 Jul 2016 04:18:42 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:29236 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752186AbcG1IS0 (ORCPT ); Thu, 28 Jul 2016 04:18:26 -0400 Message-ID: <5799BFC0.1060804@oracle.com> Date: Thu, 28 Jul 2016 16:18:08 +0800 From: Bob Liu User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130308 Thunderbird/17.0.4 MIME-Version: 1.0 To: Paolo Bonzini CC: linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, mst@redhat.com Subject: Re: [PATCH] drivers: virtio_blk: notify blk-core when hw-queue number changes References: <1465811906-24510-1-git-send-email-bob.liu__9616.24590349874$1465832216$gmane$org@oracle.com> <3cd56d3a-85f0-9cce-d42f-f4eace84667b@redhat.com> In-Reply-To: <3cd56d3a-85f0-9cce-d42f-f4eace84667b@redhat.com> Content-Type: text/plain; charset=windows-1252 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 On 06/19/2016 06:10 AM, Paolo Bonzini wrote: > > > On 13/06/2016 11:58, Bob Liu wrote: >> A guest might be migrated to other hosts with different num_queues, the >> blk-core should aware of that else the reference of &vblk->vqs[qid] may be wrong. >> >> Signed-off-by: Bob Liu >> --- >> drivers/block/virtio_blk.c | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c >> index 42758b5..c169238 100644 >> --- a/drivers/block/virtio_blk.c >> +++ b/drivers/block/virtio_blk.c >> @@ -819,6 +819,9 @@ static int virtblk_restore(struct virtio_device *vdev) >> if (ret) >> return ret; >> >> + if (vblk->num_vqs != vblk->tag_set.nr_hw_queues) >> + blk_mq_update_nr_hw_queues(&vblk->tag_set, vblk->num_vqs); >> + >> virtio_device_ready(vdev); >> >> blk_mq_start_stopped_hw_queues(vblk->disk->queue, true); >> > > This should never happen; it'd be a configuration problem. > Do you mean all hosts have to be configured with the same number of ->num_vqs? What about cases like migrating a guest from HostA to HostB while HostB is much more powerful and would like to run more hardware queues to get better performance. Thanks, Bob Liu