kernel/linux.git/drivers/vhost/net.c, branch v4.19.16

vhost: switch to use new message format

2018-08-06T17:41:04+00:00

We use to have message like: struct vhost_msg { int type; union { struct vhost_iotlb_msg iotlb; __u8 padding[64]; }; }; Unfortunately, there will be a hole of 32bit in 64bit machine because of the alignment. This leads a different formats between 32bit API and 64bit API. What's more it will break 32bit program running on 64bit machine. So fixing this by introducing a new message type with an explicit 32bit reserved field after type like: struct vhost_msg_v2 { __u32 type; __u32 reserved; union { struct vhost_iotlb_msg iotlb; __u8 padding[64]; }; }; We will have a consistent ABI after switching to use this. To enable this capability, introduce a new ioctl (VHOST_SET_BAKCEND_FEATURE) for userspace to enable this feature (VHOST_BACKEND_F_IOTLB_V2). Fixes: 6b1e6cc7855b ("vhost: new device IOTLB API") Signed-off-by: Jason Wang Signed-off-by: David S. Miller

vhost_net: batch update used ring for datacopy TX

2018-07-22T16:43:31+00:00

Like commit e2b3b35eb989 ("vhost_net: batch used ring update in rx"), this patches implements batch used ring update for datacopy TX (zerocopy has already done some kind of batching). Testpmd transmission from guest to host (XDP_DROP on tap) shows 25.8% improvement (from ~3.1Mpps to ~3.9Mpps) on Broadwell i7-5600U CPU @ 2.60GHz machine. Netperf TCP tests does not show obvious differences. Signed-off-by: Jason Wang Signed-off-by: David S. Miller

vhost_net: rename VHOST_RX_BATCH to VHOST_NET_BATCH

2018-07-22T16:43:31+00:00

A more generic name which could be used for TX as well. Signed-off-by: Jason Wang Signed-off-by: David S. Miller

vhost_net: rename vhost_rx_signal_used() to vhost_net_signal_used()

2018-07-22T16:43:31+00:00

Rename for reusing this for TX. Signed-off-by: Jason Wang Signed-off-by: David S. Miller

vhost_net: split out datacopy logic

2018-07-22T16:43:31+00:00

Instead of mixing zerocopy and datacopy logics, this patch tries to split datacopy logic out. This results for a more compact code and ad-hoc optimization could be done on top more easily. Signed-off-by: Jason Wang Signed-off-by: David S. Miller

vhost_net: introduce tx_can_batch()

2018-07-22T16:43:31+00:00

Introduce tx_can_batch() to determine whether TX could be batched. This will help to reduce the code duplication in the future. Signed-off-by: Jason Wang Signed-off-by: David S. Miller

vhost_net: introduce get_tx_bufs()

2018-07-22T16:43:31+00:00

Factor out logic of getting tx buffer and iov iter initialization. This will be used for reducing codes duplication in the future. Signed-off-by: Jason Wang Signed-off-by: David S. Miller

vhost_net: introduce vhost_exceeds_weight()

2018-07-22T16:43:30+00:00

Signed-off-by: Jason Wang Signed-off-by: David S. Miller

vhost_net: introduce helper to initialize tx iov iter

2018-07-22T16:43:30+00:00

Introduce init_iov_iter() in order to be reused by future patch. Signed-off-by: Jason Wang Signed-off-by: David S. Miller

vhost_net: drop unnecessary parameter

2018-07-22T16:43:30+00:00

Signed-off-by: Jason Wang Signed-off-by: David S. Miller