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authorRusty Russell <rusty@rustcorp.com.au>2009-08-26 12:22:32 -0700
committerDavid S. Miller <davem@davemloft.net>2009-08-26 12:22:32 -0700
commit3161e453e496eb5643faad30fff5a5ab183da0fe (patch)
tree2d115967af7e59e4085526a4f0c4e33f63b7c58c
parent0b4f2928f14c4a9770b0866923fc81beb7f4aa57 (diff)
downloadlinux-stericsson-3161e453e496eb5643faad30fff5a5ab183da0fe.tar.gz
virtio: net refill on out-of-memory
If we run out of memory, use keventd to fill the buffer. There's a report of this happening: "Page allocation failures in guest", Message-ID: <20090713115158.0a4892b0@mjolnir.ossman.eu> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/net/virtio_net.c61
1 files changed, 46 insertions, 15 deletions
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 2a6e81d5b579..bbedf03a2124 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -70,6 +70,9 @@ struct virtnet_info
struct sk_buff_head recv;
struct sk_buff_head send;
+ /* Work struct for refilling if we run low on memory. */
+ struct delayed_work refill;
+
/* Chain pages by the private ptr. */
struct page *pages;
};
@@ -273,19 +276,22 @@ drop:
dev_kfree_skb(skb);
}
-static void try_fill_recv_maxbufs(struct virtnet_info *vi)
+static bool try_fill_recv_maxbufs(struct virtnet_info *vi, gfp_t gfp)
{
struct sk_buff *skb;
struct scatterlist sg[2+MAX_SKB_FRAGS];
int num, err, i;
+ bool oom = false;
sg_init_table(sg, 2+MAX_SKB_FRAGS);
for (;;) {
struct virtio_net_hdr *hdr;
skb = netdev_alloc_skb(vi->dev, MAX_PACKET_LEN + NET_IP_ALIGN);
- if (unlikely(!skb))
+ if (unlikely(!skb)) {
+ oom = true;
break;
+ }
skb_reserve(skb, NET_IP_ALIGN);
skb_put(skb, MAX_PACKET_LEN);
@@ -296,7 +302,7 @@ static void try_fill_recv_maxbufs(struct virtnet_info *vi)
if (vi->big_packets) {
for (i = 0; i < MAX_SKB_FRAGS; i++) {
skb_frag_t *f = &skb_shinfo(skb)->frags[i];
- f->page = get_a_page(vi, GFP_ATOMIC);
+ f->page = get_a_page(vi, gfp);
if (!f->page)
break;
@@ -325,31 +331,35 @@ static void try_fill_recv_maxbufs(struct virtnet_info *vi)
if (unlikely(vi->num > vi->max))
vi->max = vi->num;
vi->rvq->vq_ops->kick(vi->rvq);
+ return !oom;
}
-static void try_fill_recv(struct virtnet_info *vi)
+/* Returns false if we couldn't fill entirely (OOM). */
+static bool try_fill_recv(struct virtnet_info *vi, gfp_t gfp)
{
struct sk_buff *skb;
struct scatterlist sg[1];
int err;
+ bool oom = false;
- if (!vi->mergeable_rx_bufs) {
- try_fill_recv_maxbufs(vi);
- return;
- }
+ if (!vi->mergeable_rx_bufs)
+ return try_fill_recv_maxbufs(vi, gfp);
for (;;) {
skb_frag_t *f;
skb = netdev_alloc_skb(vi->dev, GOOD_COPY_LEN + NET_IP_ALIGN);
- if (unlikely(!skb))
+ if (unlikely(!skb)) {
+ oom = true;
break;
+ }
skb_reserve(skb, NET_IP_ALIGN);
f = &skb_shinfo(skb)->frags[0];
- f->page = get_a_page(vi, GFP_ATOMIC);
+ f->page = get_a_page(vi, gfp);
if (!f->page) {
+ oom = true;
kfree_skb(skb);
break;
}
@@ -373,6 +383,7 @@ static void try_fill_recv(struct virtnet_info *vi)
if (unlikely(vi->num > vi->max))
vi->max = vi->num;
vi->rvq->vq_ops->kick(vi->rvq);
+ return !oom;
}
static void skb_recv_done(struct virtqueue *rvq)
@@ -385,6 +396,23 @@ static void skb_recv_done(struct virtqueue *rvq)
}
}
+static void refill_work(struct work_struct *work)
+{
+ struct virtnet_info *vi;
+ bool still_empty;
+
+ 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. */
+ if (still_empty)
+ schedule_delayed_work(&vi->refill, HZ/2);
+}
+
static int virtnet_poll(struct napi_struct *napi, int budget)
{
struct virtnet_info *vi = container_of(napi, struct virtnet_info, napi);
@@ -400,10 +428,10 @@ again:
received++;
}
- /* FIXME: If we oom and completely run out of inbufs, we need
- * to start a timer trying to fill more. */
- if (vi->num < vi->max / 2)
- try_fill_recv(vi);
+ if (vi->num < vi->max / 2) {
+ if (!try_fill_recv(vi, GFP_ATOMIC))
+ schedule_delayed_work(&vi->refill, 0);
+ }
/* Out of packets? */
if (received < budget) {
@@ -893,6 +921,7 @@ static int virtnet_probe(struct virtio_device *vdev)
vi->vdev = vdev;
vdev->priv = vi;
vi->pages = NULL;
+ INIT_DELAYED_WORK(&vi->refill, refill_work);
/* If they give us a callback when all buffers are done, we don't need
* the timer. */
@@ -941,7 +970,7 @@ static int virtnet_probe(struct virtio_device *vdev)
}
/* Last of all, set up some receive buffers. */
- try_fill_recv(vi);
+ try_fill_recv(vi, GFP_KERNEL);
/* If we didn't even get one input buffer, we're useless. */
if (vi->num == 0) {
@@ -958,6 +987,7 @@ static int virtnet_probe(struct virtio_device *vdev)
unregister:
unregister_netdev(dev);
+ cancel_delayed_work_sync(&vi->refill);
free_vqs:
vdev->config->del_vqs(vdev);
free:
@@ -986,6 +1016,7 @@ static void virtnet_remove(struct virtio_device *vdev)
BUG_ON(vi->num != 0);
unregister_netdev(vi->dev);
+ cancel_delayed_work_sync(&vi->refill);
vdev->config->del_vqs(vi->vdev);