LinuxLists.cc - [PATCH] vduse: Use proper spinlock for IRQ injection

2023-07-05 11:51:15

Subject: [PATCH] vduse: Use proper spinlock for IRQ injection

The IRQ injection work used spin_lock_irq() to protect the
scheduling of the softirq, but spin_lock_bh() should be
used.

With spin_lock_irq(), we noticed delay of more than 6
seconds between the time a NAPI polling work is scheduled
and the time it is executed.

Fixes: c8a6153b6c59 ("vduse: Introduce VDUSE - vDPA Device in Userspace")
Cc: [email protected]

Suggested-by: Jason Wang <[email protected]>
Signed-off-by: Maxime Coquelin <[email protected]>
---
drivers/vdpa/vdpa_user/vduse_dev.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index dc38ed21319d..df7869537ef1 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -935,10 +935,10 @@ static void vduse_dev_irq_inject(struct work_struct *work)
{
struct vduse_dev *dev = container_of(work, struct vduse_dev, inject);

- spin_lock_irq(&dev->irq_lock);
+ spin_lock_bh(&dev->irq_lock);
if (dev->config_cb.callback)
dev->config_cb.callback(dev->config_cb.private);
- spin_unlock_irq(&dev->irq_lock);
+ spin_unlock_bh(&dev->irq_lock);
}

static void vduse_vq_irq_inject(struct work_struct *work)
@@ -946,10 +946,10 @@ static void vduse_vq_irq_inject(struct work_struct *work)
struct vduse_virtqueue *vq = container_of(work,
struct vduse_virtqueue, inject);

- spin_lock_irq(&vq->irq_lock);
+ spin_lock_bh(&vq->irq_lock);
if (vq->ready && vq->cb.callback)
vq->cb.callback(vq->cb.private);
- spin_unlock_irq(&vq->irq_lock);
+ spin_unlock_bh(&vq->irq_lock);
}

static bool vduse_vq_signal_irqfd(struct vduse_virtqueue *vq)
--
2.41.0

2023-07-26 06:19:37

by Jason Wang

[permalink] [raw]

Subject: Re: [PATCH] vduse: Use proper spinlock for IRQ injection

On Wed, Jul 5, 2023 at 7:45 PM Maxime Coquelin
<[email protected]> wrote:
>
> The IRQ injection work used spin_lock_irq() to protect the
> scheduling of the softirq, but spin_lock_bh() should be
> used.
>
> With spin_lock_irq(), we noticed delay of more than 6
> seconds between the time a NAPI polling work is scheduled
> and the time it is executed.
>
> Fixes: c8a6153b6c59 ("vduse: Introduce VDUSE - vDPA Device in Userspace")
> Cc: [email protected]
>
> Suggested-by: Jason Wang <[email protected]>
> Signed-off-by: Maxime Coquelin <[email protected]>

Acked-by: Jason Wang <[email protected]>

Thanks

> ---
> drivers/vdpa/vdpa_user/vduse_dev.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
> index dc38ed21319d..df7869537ef1 100644
> --- a/drivers/vdpa/vdpa_user/vduse_dev.c
> +++ b/drivers/vdpa/vdpa_user/vduse_dev.c
> @@ -935,10 +935,10 @@ static void vduse_dev_irq_inject(struct work_struct *work)
> {
> struct vduse_dev *dev = container_of(work, struct vduse_dev, inject);
>
> - spin_lock_irq(&dev->irq_lock);
> + spin_lock_bh(&dev->irq_lock);
> if (dev->config_cb.callback)
> dev->config_cb.callback(dev->config_cb.private);
> - spin_unlock_irq(&dev->irq_lock);
> + spin_unlock_bh(&dev->irq_lock);
> }
>
> static void vduse_vq_irq_inject(struct work_struct *work)
> @@ -946,10 +946,10 @@ static void vduse_vq_irq_inject(struct work_struct *work)
> struct vduse_virtqueue *vq = container_of(work,
> struct vduse_virtqueue, inject);
>
> - spin_lock_irq(&vq->irq_lock);
> + spin_lock_bh(&vq->irq_lock);
> if (vq->ready && vq->cb.callback)
> vq->cb.callback(vq->cb.private);
> - spin_unlock_irq(&vq->irq_lock);
> + spin_unlock_bh(&vq->irq_lock);
> }
>
> static bool vduse_vq_signal_irqfd(struct vduse_virtqueue *vq)
> --
> 2.41.0
>

2023-07-31 03:21:03

by Yongji Xie

[permalink] [raw]