When transmitting a vsock packet, virtio_transport_send_pkt_info() calls virtio_transport_alloc_linear_skb() to allocate and fill SKBs with the transmit data. Unfortunately, these are always linear allocations and can therefore result in significant pressure on kmalloc() considering that the maximum packet size (VIRTIO_VSOCK_MAX_PKT_BUF_SIZE + VIRTIO_VSOCK_SKB_HEADROOM) is a little over 64KiB, resulting in a 128KiB allocation for each packet.
Rework the vsock SKB allocation so that, for sizes with page order greater than PAGE_ALLOC_COSTLY_ORDER, a nonlinear SKB is allocated instead with the packet header in the SKB and the transmit data in the fragments. Note that this affects both the vhost and virtio transports. Reviewed-by: Stefano Garzarella <sgarz...@redhat.com> Signed-off-by: Will Deacon <w...@kernel.org> --- net/vmw_vsock/virtio_transport_common.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c index c9eb7f7ac00d..fe92e5fa95b4 100644 --- a/net/vmw_vsock/virtio_transport_common.c +++ b/net/vmw_vsock/virtio_transport_common.c @@ -109,7 +109,8 @@ static int virtio_transport_fill_skb(struct sk_buff *skb, return __zerocopy_sg_from_iter(info->msg, NULL, skb, &info->msg->msg_iter, len, NULL); - return memcpy_from_msg(skb_put(skb, len), info->msg, len); + virtio_vsock_skb_put(skb, len); + return skb_copy_datagram_from_iter(skb, 0, &info->msg->msg_iter, len); } static void virtio_transport_init_hdr(struct sk_buff *skb, @@ -261,7 +262,7 @@ static struct sk_buff *virtio_transport_alloc_skb(struct virtio_vsock_pkt_info * if (!zcopy) skb_len += payload_len; - skb = virtio_vsock_alloc_linear_skb(skb_len, GFP_KERNEL); + skb = virtio_vsock_alloc_skb(skb_len, GFP_KERNEL); if (!skb) return NULL; -- 2.50.0.727.gbf7dc18ff4-goog