From 31304165ffb888483e0f7c805876f25f493a3049 Mon Sep 17 00:00:00 2001 From: Torsten Kaiser Date: Mon, 9 Apr 2012 05:14:15 +0000 Subject: net: Fix misplaced parenthesis in virtio_net.c Commit 2e57b79ccef1ff1422fdf45a9b28fe60f8f084f7 misplaced its parenthesis and now tx_fifo_errors will only be incremented if an ENOMEM error is not written to the syslog. Correct the parenthesis and indentation to the original goal of counting all non ENOMEM errors and ratelimiting only the messages. Signed-of-by: Torsten Kaiser Signed-off-by: David S. Miller --- drivers/net/virtio_net.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'drivers/net/virtio_net.c') diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 4de2760c5937..af8acc85f4bb 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -626,16 +626,15 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev) /* This can happen with OOM and indirect buffers. */ if (unlikely(capacity < 0)) { if (likely(capacity == -ENOMEM)) { - if (net_ratelimit()) { + if (net_ratelimit()) dev_warn(&dev->dev, "TX queue failure: out of memory\n"); - } else { + } else { dev->stats.tx_fifo_errors++; if (net_ratelimit()) dev_warn(&dev->dev, "Unexpected TX queue failure: %d\n", capacity); - } } dev->stats.tx_dropped++; kfree_skb(skb); -- cgit v1.2.3 From ec13ee80145ccb95b00e6e610044bbd94a170051 Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Wed, 16 May 2012 10:57:12 +0300 Subject: virtio_net: invoke softirqs after __napi_schedule __napi_schedule might raise softirq but nothing causes do_softirq to trigger, so it does not in fact run. As a result, the error message "NOHZ: local_softirq_pending 08" sometimes occurs during boot of a KVM guest when the network service is started and we are oom: ... Bringing up loopback interface: [ OK ] Bringing up interface eth0: Determining IP information for eth0...NOHZ: local_softirq_pending 08 done. [ OK ] ... Further, receive queue processing might get delayed indefinitely until some interrupt triggers: virtio_net expected napi to be run immediately. One way to cause do_softirq to be executed is by invoking local_bh_enable(). As __napi_schedule is normally called from bh or irq context, this seems to make sense: disable bh before __napi_schedule and enable afterwards. In fact it's a very complicated way of calling do_softirq(), and works since this function is only used when we are not in interrupt context. It's not hot at all, in any ideal scenario. Reported-by: Ulrich Obergfell Tested-by: Ulrich Obergfell Signed-off-by: Michael S. Tsirkin Acked-by: Rusty Russell --- drivers/net/virtio_net.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'drivers/net/virtio_net.c') diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index af8acc85f4bb..cbefe671bcc6 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -492,7 +492,9 @@ static void virtnet_napi_enable(struct virtnet_info *vi) * We synchronize against interrupts via NAPI_STATE_SCHED */ if (napi_schedule_prep(&vi->napi)) { virtqueue_disable_cb(vi->rvq); + local_bh_disable(); __napi_schedule(&vi->napi); + local_bh_enable(); } } -- cgit v1.2.3