similar to: [PATCH v2] virtio-net: free bufs correctly on invalid packet length

When a packet with invalid length arrives, ensure that the packet is freed correctly if mergeable packet buffers and big packets (GUEST_TSO4) are both enabled. --- drivers/net/virtio_net.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 916241d..6a4665c 100644 --- a/drivers/net/virtio_net.c +++

When a packet with invalid length arrives, ensure that the packet is freed correctly if mergeable packet buffers and big packets (GUEST_TSO4) are both enabled. --- drivers/net/virtio_net.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 916241d..6a4665c 100644 --- a/drivers/net/virtio_net.c +++

On 12/05/2013 10:36 PM, Andrey Vagin wrote: > free_unused_bufs must check vi->mergeable_rx_bufs before > vi->big_packets, because we use this sequence in other places. > Otherwise we allocate buffer of one type, then free it as another > type. > > general protection fault: 0000 [#1] SMP > Dumping ftrace buffer: > (ftrace buffer empty) > Modules linked in:

On 12/05/2013 10:36 PM, Andrey Vagin wrote: > free_unused_bufs must check vi->mergeable_rx_bufs before > vi->big_packets, because we use this sequence in other places. > Otherwise we allocate buffer of one type, then free it as another > type. > > general protection fault: 0000 [#1] SMP > Dumping ftrace buffer: > (ftrace buffer empty) > Modules linked in:

They can be easy to reproduce, if you try to unload virtio-net Andrey Vagin (2): virtio-net: determine type of bufs correctly virtio: delete napi objects from netdev before releasing memory drivers/net/virtio_net.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) Cc: Rusty Russell <rusty at rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst at redhat.com>

They can be easy to reproduce, if you try to unload virtio-net Andrey Vagin (2): virtio-net: determine type of bufs correctly virtio: delete napi objects from netdev before releasing memory drivers/net/virtio_net.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) Cc: Rusty Russell <rusty at rustcorp.com.au> Cc: "Michael S. Tsirkin" <mst at redhat.com>

The virtio_net driver's mergeable receive buffer allocator uses 4KB packet buffers. For MTU-sized traffic, SKB truesize is > 4KB but only ~1500 bytes of the buffer is used to store packet data, reducing the effective TCP window size substantially. This patch addresses the performance concerns with mergeable receive buffers by allocating MTU-sized packet buffers using page frag allocators.

The virtio_net driver's mergeable receive buffer allocator uses 4KB packet buffers. For MTU-sized traffic, SKB truesize is > 4KB but only ~1500 bytes of the buffer is used to store packet data, reducing the effective TCP window size substantially. This patch addresses the performance concerns with mergeable receive buffers by allocating MTU-sized packet buffers using page frag allocators.

skb_page_frag_refill currently permits only order-0 page allocs unless GFP_WAIT is used. Change skb_page_frag_refill to attempt higher-order page allocations whether or not GFP_WAIT is used. If memory cannot be allocated, the allocator will fall back to successively smaller page allocs (down to order-0 page allocs). This change brings skb_page_frag_refill in line with the existing page allocation

skb_page_frag_refill currently permits only order-0 page allocs unless GFP_WAIT is used. Change skb_page_frag_refill to attempt higher-order page allocations whether or not GFP_WAIT is used. If memory cannot be allocated, the allocator will fall back to successively smaller page allocs (down to order-0 page allocs). This change brings skb_page_frag_refill in line with the existing page allocation

receive mergeable now handles errors internally. Do same for big and small packet paths, otherwise the logic is too hard to follow. Cc: Jason Wang <jasowang at redhat.com> Cc: David S. Miller <davem at davemloft.net> Acked-by: Michael Dalton <mwdalton at google.com> Signed-off-by: Michael S. Tsirkin <mst at redhat.com> (cherry picked from commit

receive mergeable now handles errors internally. Do same for big and small packet paths, otherwise the logic is too hard to follow. Cc: Jason Wang <jasowang at redhat.com> Cc: David S. Miller <davem at davemloft.net> Acked-by: Michael Dalton <mwdalton at google.com> Signed-off-by: Michael S. Tsirkin <mst at redhat.com> (cherry picked from commit

skb_page_frag_refill currently permits only order-0 page allocs unless GFP_WAIT is used. Change skb_page_frag_refill to attempt higher-order page allocations whether or not GFP_WAIT is used. If memory cannot be allocated, the allocator will fall back to successively smaller page allocs (down to order-0 page allocs). This change brings skb_page_frag_refill in line with the existing page allocation

skb_page_frag_refill currently permits only order-0 page allocs unless GFP_WAIT is used. Change skb_page_frag_refill to attempt higher-order page allocations whether or not GFP_WAIT is used. If memory cannot be allocated, the allocator will fall back to successively smaller page allocs (down to order-0 page allocs). This change brings skb_page_frag_refill in line with the existing page allocation

The virtio-net device currently uses aligned MTU-sized mergeable receive packet buffers. Network throughput for workloads with large average packet size can be improved by posting larger receive packet buffers. However, due to SKB truesize effects, posting large (e.g, PAGE_SIZE) buffers reduces the throughput of workloads that do not benefit from GRO and have no large inbound packets. This

The virtio-net device currently uses aligned MTU-sized mergeable receive packet buffers. Network throughput for workloads with large average packet size can be improved by posting larger receive packet buffers. However, due to SKB truesize effects, posting large (e.g, PAGE_SIZE) buffers reduces the throughput of workloads that do not benefit from GRO and have no large inbound packets. This

The virtio-net device currently uses aligned MTU-sized mergeable receive packet buffers. Network throughput for workloads with large average packet size can be improved by posting larger receive packet buffers. However, due to SKB truesize effects, posting large (e.g, PAGE_SIZE) buffers reduces the throughput of workloads that do not benefit from GRO and have no large inbound packets. This

The virtio-net device currently uses aligned MTU-sized mergeable receive packet buffers. Network throughput for workloads with large average packet size can be improved by posting larger receive packet buffers. However, due to SKB truesize effects, posting large (e.g, PAGE_SIZE) buffers reduces the throughput of workloads that do not benefit from GRO and have no large inbound packets. This

Eric Dumazet noticed that if we encounter an error when processing a mergeable buffer, we don't dequeue all of the buffers from this packet, the result is almost sure to be loss of networking. Jason Wang noticed that we also leak a page and that we don't decrement the rq buf count, so we won't repost buffers (a resource leak). Fix both issues. Cc: Rusty Russell <rusty at

Eric Dumazet noticed that if we encounter an error when processing a mergeable buffer, we don't dequeue all of the buffers from this packet, the result is almost sure to be loss of networking. Jason Wang noticed that we also leak a page and that we don't decrement the rq buf count, so we won't repost buffers (a resource leak). Fix both issues. Cc: Rusty Russell <rusty at