similar to: [PATCH] virtio_net: fix use after free

On 2018/12/6 ??6:54, Michael S. Tsirkin wrote: > When use_napi is set, let's enable BQLs. Note: some of the issues are > similar to wifi. It's worth considering whether something similar to > commit 36148c2bbfbe ("mac80211: Adjust TSQ pacing shift") might be > benefitial. I've played a similar patch several days before. The tricky part is the mode switching

On 2018/12/6 ??6:54, Michael S. Tsirkin wrote: > When use_napi is set, let's enable BQLs. Note: some of the issues are > similar to wifi. It's worth considering whether something similar to > commit 36148c2bbfbe ("mac80211: Adjust TSQ pacing shift") might be > benefitial. I've played a similar patch several days before. The tricky part is the mode switching

According to David, proper accounting and queueing (at all levels, not just TCP sockets) is more important than trying to skim a bunch of cycles by avoiding TX interrupts. Having an event to free the SKB is absolutely essential for the stack to operate correctly. This series tries to enable tx interrupt for virtio-net. The idea is simple: enable tx interrupt and schedule a tx napi to free old

According to David, proper accounting and queueing (at all levels, not just TCP sockets) is more important than trying to skim a bunch of cycles by avoiding TX interrupts. Having an event to free the SKB is absolutely essential for the stack to operate correctly. This series tries to enable tx interrupt for virtio-net. The idea is simple: enable tx interrupt and schedule a tx napi to free old

Now that we have brought the virtio overhead way down with a fast packed ring implementation, we seem to be actually observing TCP drops indicative of bufferbloat. So let's try to enable TSQ. Note: it isn't clear that the default pacing is great for the virt usecase. It's worth trying to play with sk_pacing_shift_update to see what happens. For this reason, and for a more important

On 2018/12/26 ??11:19, Michael S. Tsirkin wrote: > On Thu, Dec 06, 2018 at 04:17:36PM +0800, Jason Wang wrote: >> On 2018/12/6 ??6:54, Michael S. Tsirkin wrote: >>> When use_napi is set, let's enable BQLs. Note: some of the issues are >>> similar to wifi. It's worth considering whether something similar to >>> commit 36148c2bbfbe ("mac80211:

On 2018/12/26 ??11:19, Michael S. Tsirkin wrote: > On Thu, Dec 06, 2018 at 04:17:36PM +0800, Jason Wang wrote: >> On 2018/12/6 ??6:54, Michael S. Tsirkin wrote: >>> When use_napi is set, let's enable BQLs. Note: some of the issues are >>> similar to wifi. It's worth considering whether something similar to >>> commit 36148c2bbfbe ("mac80211:

On Wed, 2014-10-15 at 16:23 +0300, Michael S. Tsirkin wrote: > commit 0b725a2ca61bedc33a2a63d0451d528b268cf975 > net: Remove ndo_xmit_flush netdev operation, use signalling instead. > > added code that looks at skb->xmit_more after the skb has > been put in TX VQ. Since some paths process the ring and free the skb > immediately, this can cause use after free. > >

From: Michael S. Tsirkin > commit 0b725a2ca61bedc33a2a63d0451d528b268cf975 > net: Remove ndo_xmit_flush netdev operation, use signalling instead. > > added code that looks at skb->xmit_more after the skb has > been put in TX VQ. Since some paths process the ring and free the skb > immediately, this can cause use after free. > > Fix by storing xmit_more in a local

On 2018/12/26 ??11:22, Michael S. Tsirkin wrote: > On Thu, Dec 06, 2018 at 04:17:36PM +0800, Jason Wang wrote: >> On 2018/12/6 ??6:54, Michael S. Tsirkin wrote: >>> When use_napi is set, let's enable BQLs. Note: some of the issues are >>> similar to wifi. It's worth considering whether something similar to >>> commit 36148c2bbfbe ("mac80211:

On 2018/12/26 ??11:22, Michael S. Tsirkin wrote: > On Thu, Dec 06, 2018 at 04:17:36PM +0800, Jason Wang wrote: >> On 2018/12/6 ??6:54, Michael S. Tsirkin wrote: >>> When use_napi is set, let's enable BQLs. Note: some of the issues are >>> similar to wifi. It's worth considering whether something similar to >>> commit 36148c2bbfbe ("mac80211:

On 2018?01?12? 13:58, Sridhar Samudrala wrote: > static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev) > { > struct virtnet_info *vi = netdev_priv(dev); > int qnum = skb_get_queue_mapping(skb); > struct send_queue *sq = &vi->sq[qnum]; > + struct net_device *vf_netdev; > int err; > struct netdev_queue *txq =

On 2018?01?12? 13:58, Sridhar Samudrala wrote: > static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev) > { > struct virtnet_info *vi = netdev_priv(dev); > int qnum = skb_get_queue_mapping(skb); > struct send_queue *sq = &vi->sq[qnum]; > + struct net_device *vf_netdev; > int err; > struct netdev_queue *txq =

On 10/31/2014 11:36 AM, Eric Dumazet wrote: > On Wed, 2014-10-15 at 16:23 +0300, Michael S. Tsirkin wrote: >> commit 0b725a2ca61bedc33a2a63d0451d528b268cf975 >> net: Remove ndo_xmit_flush netdev operation, use signalling instead. >> >> added code that looks at skb->xmit_more after the skb has >> been put in TX VQ. Since some paths process the ring and free

On 10/31/2014 11:36 AM, Eric Dumazet wrote: > On Wed, 2014-10-15 at 16:23 +0300, Michael S. Tsirkin wrote: >> commit 0b725a2ca61bedc33a2a63d0451d528b268cf975 >> net: Remove ndo_xmit_flush netdev operation, use signalling instead. >> >> added code that looks at skb->xmit_more after the skb has >> been put in TX VQ. Since some paths process the ring and free

Improve tx batching using byte queue limits. Should be especially effective for MQ. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/net/virtio_net.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index a9bf178..8dea411 100644 --- a/drivers/net/virtio_net.c +++

Improve tx batching using byte queue limits. Should be especially effective for MQ. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/net/virtio_net.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index a9bf178..8dea411 100644 --- a/drivers/net/virtio_net.c +++

On 2018/12/31 ??2:45, Michael S. Tsirkin wrote: > On Thu, Dec 27, 2018 at 06:00:36PM +0800, Jason Wang wrote: >> On 2018/12/26 ??11:19, Michael S. Tsirkin wrote: >>> On Thu, Dec 06, 2018 at 04:17:36PM +0800, Jason Wang wrote: >>>> On 2018/12/6 ??6:54, Michael S. Tsirkin wrote: >>>>> When use_napi is set, let's enable BQLs. Note: some of the issues

On 2018/12/31 ??2:45, Michael S. Tsirkin wrote: > On Thu, Dec 27, 2018 at 06:00:36PM +0800, Jason Wang wrote: >> On 2018/12/26 ??11:19, Michael S. Tsirkin wrote: >>> On Thu, Dec 06, 2018 at 04:17:36PM +0800, Jason Wang wrote: >>>> On 2018/12/6 ??6:54, Michael S. Tsirkin wrote: >>>>> When use_napi is set, let's enable BQLs. Note: some of the issues

On newer hosts that support delayed tx interrupts, we probably don't have much to gain from orphaning packets early. Based on patch by Jason Wang. Note: this might degrade performance for hosts without event idx support. Should be addressed by the next patch. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/net/virtio_net.c | 137