Re: Page allocation failures in guest

Rusty Russell
2009-08-12T06:56:30Z

On Wed, 12 Aug 2009 03:11:21 pm Avi Kivity wrote:
> > + /* In theory, this can happen: if we don't get any buffers in
> > + * we will*never* try to fill again. Sleeping in keventd if
> > + * bad, but that is worse. */
> > + if (still_empty) {
> > + msleep(100);
> > + schedule_work(&vi->refill);
> > + }
> > +}
> > +
>
> schedule_delayed_work()?

Hmm, might as well, although this is v. unlikely to happen.

Thanks,
Rusty.

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -72,7 +72,7 @@ struct virtnet_info
struct sk_buff_head send;

/* Work struct for refilling if we run low on memory. */
- struct work_struct refill;
+ struct delayed_work refill;

/* Chain pages by the private ptr. */
struct page *pages;
@@ -402,19 +402,16 @@ static void refill_work(struct work_stru
struct virtnet_info *vi;
bool still_empty;

- vi = container_of(work, struct virtnet_info, refill);
+ vi = container_of(work, struct virtnet_info, refill.work);
napi_disable(&vi->napi);
try_fill_recv(vi, GFP_KERNEL);
still_empty = (vi->num == 0);
napi_enable(&vi->napi);

/* In theory, this can happen: if we don't get any buffers in
- * we will *never* try to fill again. Sleeping in keventd if
- * bad, but that is worse. */
- if (still_empty) {
- msleep(100);
- schedule_work(&vi->refill);
- }
+ * we will *never* try to fill again. */
+ if (still_empty)
+ schedule_delayed_work(&vi->refill, HZ/2);
}

static int virtnet_poll(struct napi_struct *napi, int budget)
@@ -434,7 +431,7 @@ again:

if (vi->num < vi->max / 2) {
if (!try_fill_recv(vi, GFP_ATOMIC))
- schedule_work(&vi->refill);
+ schedule_delayed_work(&vi->refill, 0);
}

/* Out of packets? */
@@ -925,7 +922,7 @@ static int virtnet_probe(struct virtio_d
vi->vdev = vdev;
vdev->priv = vi;
vi->pages = NULL;
- INIT_WORK(&vi->refill, refill_work);
+ INIT_DELAYED_WORK(&vi->refill, refill_work);

/* If they give us a callback when all buffers are done, we don't need
* the timer. */
@@ -991,7 +988,7 @@ static int virtnet_probe(struct virtio_d

unregister:
unregister_netdev(dev);
- cancel_work_sync(&vi->refill);
+ cancel_delayed_work_sync(&vi->refill);
free_vqs:
vdev->config->del_vqs(vdev);
free:
@@ -1020,7 +1017,7 @@ static void virtnet_remove(struct virtio
BUG_ON(vi->num != 0);

unregister_netdev(vi->dev);
- cancel_work_sync(&vi->refill);
+ cancel_delayed_work_sync(&vi->refill);

vdev->config->del_vqs(vi->vdev);