diff mbox series

[v3,09/11] vduse: Signal interrupt's eventfd directly in vhost-vdpa case

Message ID 20230228094110.37-10-xieyongji@bytedance.com
State New
Headers
Series VDUSE: Improve performance |

Commit Message

Yongji Xie Feb. 28, 2023, 9:41 a.m. UTC 
  Now the vdpa callback will associate an eventfd in
vhost-vdpa case. For performance reasons, VDUSE can
signal it directly during irq injection.

Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
---
 drivers/vdpa/vdpa_user/vduse_dev.c | 27 +++++++++++++++++++++++----
 1 file changed, 23 insertions(+), 4 deletions(-)

Comments

Jason Wang March 16, 2023, 9:30 a.m. UTC | #1 
On Tue, Feb 28, 2023 at 5:42 PM Xie Yongji <xieyongji@bytedance.com> wrote:
>
> Now the vdpa callback will associate an eventfd in
> vhost-vdpa case.

I'd suggest avoiding mentioning drivers since vDPA parents should not
know which vDPA driver is bound.

We could say "signal vq trigger eventfd directly if possible"?

With those tweaked.

Acked-by: Jason Wang <jasowang@redhat.com>

Thanks

> For performance reasons, VDUSE can
> signal it directly during irq injection.
>
> Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
> ---
>  drivers/vdpa/vdpa_user/vduse_dev.c | 27 +++++++++++++++++++++++----
>  1 file changed, 23 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
> index 869cc7860d82..56f3c2480c2a 100644
> --- a/drivers/vdpa/vdpa_user/vduse_dev.c
> +++ b/drivers/vdpa/vdpa_user/vduse_dev.c
> @@ -461,6 +461,7 @@ static void vduse_dev_reset(struct vduse_dev *dev)
>                 spin_lock(&vq->irq_lock);
>                 vq->cb.callback = NULL;
>                 vq->cb.private = NULL;
> +               vq->cb.irq_ctx = NULL;
>                 spin_unlock(&vq->irq_lock);
>                 flush_work(&vq->inject);
>                 flush_work(&vq->kick);
> @@ -526,6 +527,7 @@ static void vduse_vdpa_set_vq_cb(struct vdpa_device *vdpa, u16 idx,
>         spin_lock(&vq->irq_lock);
>         vq->cb.callback = cb->callback;
>         vq->cb.private = cb->private;
> +       vq->cb.irq_ctx = cb->irq_ctx;
>         spin_unlock(&vq->irq_lock);
>  }
>
> @@ -1020,6 +1022,20 @@ static void vduse_vq_irq_inject(struct work_struct *work)
>         spin_unlock_irq(&vq->irq_lock);
>  }
>
> +static bool vduse_vq_signal_irqfd(struct vduse_virtqueue *vq)
> +{
> +       bool signal = false;
> +
> +       spin_lock_irq(&vq->irq_lock);
> +       if (vq->ready && vq->cb.irq_ctx) {
> +               eventfd_signal(vq->cb.irq_ctx, 1);
> +               signal = true;
> +       }
> +       spin_unlock_irq(&vq->irq_lock);
> +
> +       return signal;
> +}
> +
>  static int vduse_dev_queue_irq_work(struct vduse_dev *dev,
>                                     struct work_struct *irq_work,
>                                     int irq_effective_cpu)
> @@ -1322,11 +1338,14 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
>                 if (index >= dev->vq_num)
>                         break;
>
> +               ret = 0;
>                 index = array_index_nospec(index, dev->vq_num);
> -
> -               vduse_vq_update_effective_cpu(dev->vqs[index]);
> -               ret = vduse_dev_queue_irq_work(dev, &dev->vqs[index]->inject,
> -                                       dev->vqs[index]->irq_effective_cpu);
> +               if (!vduse_vq_signal_irqfd(dev->vqs[index])) {
> +                       vduse_vq_update_effective_cpu(dev->vqs[index]);
> +                       ret = vduse_dev_queue_irq_work(dev,
> +                                               &dev->vqs[index]->inject,
> +                                               dev->vqs[index]->irq_effective_cpu);
> +               }
>                 break;
>         }
>         case VDUSE_IOTLB_REG_UMEM: {
> --
> 2.20.1
>
Yongji Xie March 17, 2023, 7:01 a.m. UTC | #2 
On Thu, Mar 16, 2023 at 5:31 PM Jason Wang <jasowang@redhat.com> wrote:
>
> On Tue, Feb 28, 2023 at 5:42 PM Xie Yongji <xieyongji@bytedance.com> wrote:
> >
> > Now the vdpa callback will associate an eventfd in
> > vhost-vdpa case.
>
> I'd suggest avoiding mentioning drivers since vDPA parents should not
> know which vDPA driver is bound.
>
> We could say "signal vq trigger eventfd directly if possible"?
>

It makes sense to me.

Thanks,
Yongji
diff mbox series

Patch

diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index 869cc7860d82..56f3c2480c2a 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -461,6 +461,7 @@  static void vduse_dev_reset(struct vduse_dev *dev)
 		spin_lock(&vq->irq_lock);
 		vq->cb.callback = NULL;
 		vq->cb.private = NULL;
+		vq->cb.irq_ctx = NULL;
 		spin_unlock(&vq->irq_lock);
 		flush_work(&vq->inject);
 		flush_work(&vq->kick);
@@ -526,6 +527,7 @@  static void vduse_vdpa_set_vq_cb(struct vdpa_device *vdpa, u16 idx,
 	spin_lock(&vq->irq_lock);
 	vq->cb.callback = cb->callback;
 	vq->cb.private = cb->private;
+	vq->cb.irq_ctx = cb->irq_ctx;
 	spin_unlock(&vq->irq_lock);
 }
 
@@ -1020,6 +1022,20 @@  static void vduse_vq_irq_inject(struct work_struct *work)
 	spin_unlock_irq(&vq->irq_lock);
 }
 
+static bool vduse_vq_signal_irqfd(struct vduse_virtqueue *vq)
+{
+	bool signal = false;
+
+	spin_lock_irq(&vq->irq_lock);
+	if (vq->ready && vq->cb.irq_ctx) {
+		eventfd_signal(vq->cb.irq_ctx, 1);
+		signal = true;
+	}
+	spin_unlock_irq(&vq->irq_lock);
+
+	return signal;
+}
+
 static int vduse_dev_queue_irq_work(struct vduse_dev *dev,
 				    struct work_struct *irq_work,
 				    int irq_effective_cpu)
@@ -1322,11 +1338,14 @@  static long vduse_dev_ioctl(struct file *file, unsigned int cmd,
 		if (index >= dev->vq_num)
 			break;
 
+		ret = 0;
 		index = array_index_nospec(index, dev->vq_num);
-
-		vduse_vq_update_effective_cpu(dev->vqs[index]);
-		ret = vduse_dev_queue_irq_work(dev, &dev->vqs[index]->inject,
-					dev->vqs[index]->irq_effective_cpu);
+		if (!vduse_vq_signal_irqfd(dev->vqs[index])) {
+			vduse_vq_update_effective_cpu(dev->vqs[index]);
+			ret = vduse_dev_queue_irq_work(dev,
+						&dev->vqs[index]->inject,
+						dev->vqs[index]->irq_effective_cpu);
+		}
 		break;
 	}
 	case VDUSE_IOTLB_REG_UMEM: {