linux-kernel - Re: [PATCH V6 5/5] virtio-scsi: reset virtqueue affinity when doing cpu hotplug

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Message-ID: <20130320072425.GA23182@hj.localdomain>
Date:	Wed, 20 Mar 2013 15:24:25 +0800
From:	Asias He <asias@...hat.com>
To:	Wanlong Gao <gaowanlong@...fujitsu.com>
Cc:	linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
	linux-scsi@...r.kernel.org,
	virtualization@...ts.linux-foundation.org, rusty@...tcorp.com.au,
	mst@...hat.com, JBottomley@...allels.com, venkateshs@...gle.com,
	pbonzini@...hat.com
Subject: Re: [PATCH V6 5/5] virtio-scsi: reset virtqueue affinity when doing
 cpu hotplug

On Wed, Mar 20, 2013 at 03:01:24PM +0800, Wanlong Gao wrote:
> Add hot cpu notifier to reset the request virtqueue affinity
> when doing cpu hotplug.
> 
> Cc: linux-scsi@...r.kernel.org
> Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
> Signed-off-by: Wanlong Gao <gaowanlong@...fujitsu.com>
> Reviewed-by: Asias He <asias@...hat.com>
> ---
>  drivers/scsi/virtio_scsi.c | 29 +++++++++++++++++++++++++++++
>  1 file changed, 29 insertions(+)
> 
> diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
> index 13d7672..0ad9017 100644
> --- a/drivers/scsi/virtio_scsi.c
> +++ b/drivers/scsi/virtio_scsi.c
> @@ -110,6 +110,9 @@ struct virtio_scsi {
>  	/* if the affinity hint is set for virtqueues */
>  	bool affinity_hint_set;
>  
> +	/* CPU hotplug notifier */
> +	struct notifier_block nb;
> +
>  	struct virtio_scsi_vq ctrl_vq;
>  	struct virtio_scsi_vq event_vq;
>  	struct virtio_scsi_vq req_vqs[];
> @@ -762,6 +765,23 @@ static void virtscsi_set_affinity(struct virtio_scsi *vscsi, bool affinity)
>  	put_online_cpus();
>  }
>  
> +static int virtscsi_cpu_callback(struct notifier_block *nfb,
> +				 unsigned long action, void *hcpu)
> +{
> +	struct virtio_scsi *vscsi = container_of(nfb, struct virtio_scsi, nb);
> +	switch(action) {
> +	case CPU_ONLINE:
> +	case CPU_ONLINE_FROZEN:
> +	case CPU_DEAD:
> +	case CPU_DEAD_FROZEN:
> +		__virtscsi_set_affinity(vscsi, true);
> +		break;
> +	default:
> +		break;
> +	}
> +	return NOTIFY_OK;
> +}
> +
>  static void virtscsi_init_vq(struct virtio_scsi_vq *virtscsi_vq,
>  			     struct virtqueue *vq)
>  {
> @@ -884,6 +904,13 @@ static int virtscsi_probe(struct virtio_device *vdev)
>  	if (err)
>  		goto virtscsi_init_failed;
>  
> +	vscsi->nb.notifier_call = &virtscsi_cpu_callback;
> +	err = register_hotcpu_notifier(&vscsi->nb);
> +	if (err) {
> +		pr_err("registering cpu notifier failed\n");
> +		goto scsi_add_host_failed;
> +	}
> +
>  	cmd_per_lun = virtscsi_config_get(vdev, cmd_per_lun) ?: 1;
>  	shost->cmd_per_lun = min_t(u32, cmd_per_lun, shost->can_queue);
>  	shost->max_sectors = virtscsi_config_get(vdev, max_sectors) ?: 0xFFFF;
> @@ -921,6 +948,8 @@ static void virtscsi_remove(struct virtio_device *vdev)
>  
>  	scsi_remove_host(shost);
>  
> +	unregister_hotcpu_notifier(&vscsi->nb);
> +
>  	virtscsi_remove_vqs(vdev);
>  	scsi_host_put(shost);
>  }
> -- 
> 1.8.2.rc2
> 

This one does not apply on top of virtio-next + patch 1-4 in this series.

-- 
Asias
--
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