diff options
| author | Shachar Raindel <shacharr@microsoft.com> | 2021-03-12 15:45:27 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2021-03-14 14:32:37 -0700 |
| commit | bd49fea7586b9d39a38846e9ef4ac056e4eb6e59 (patch) | |
| tree | 2f24bccd2826e7b7080342dbeaf9e40c73a29c3c /Documentation/networking/device_drivers | |
| parent | 0f88e6f35b314500ba4c2f7d62c4598bf2c1229b (diff) | |
hv_netvsc: Add a comment clarifying batching logic
The batching logic in netvsc_send is non-trivial, due to
a combination of the Linux API and the underlying hypervisor
interface. Add a comment explaining why the code is written this
way.
Signed-off-by: Shachar Raindel <shacharr@microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Reviewed-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'Documentation/networking/device_drivers')
| -rw-r--r-- | Documentation/networking/device_drivers/ethernet/microsoft/netvsc.rst | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/Documentation/networking/device_drivers/ethernet/microsoft/netvsc.rst b/Documentation/networking/device_drivers/ethernet/microsoft/netvsc.rst index c3f51c672a68..fc5acd427a5d 100644 --- a/Documentation/networking/device_drivers/ethernet/microsoft/netvsc.rst +++ b/Documentation/networking/device_drivers/ethernet/microsoft/netvsc.rst @@ -87,11 +87,15 @@ Receive Buffer contain one or more packets. The number of receive sections may be changed via ethtool Rx ring parameters. - There is a similar send buffer which is used to aggregate packets for sending. - The send area is broken into chunks of 6144 bytes, each of section may - contain one or more packets. The send buffer is an optimization, the driver - will use slower method to handle very large packets or if the send buffer - area is exhausted. + There is a similar send buffer which is used to aggregate packets + for sending. The send area is broken into chunks, typically of 6144 + bytes, each of section may contain one or more packets. Small + packets are usually transmitted via copy to the send buffer. However, + if the buffer is temporarily exhausted, or the packet to be transmitted is + an LSO packet, the driver will provide the host with pointers to the data + from the SKB. This attempts to achieve a balance between the overhead of + data copy and the impact of remapping VM memory to be accessible by the + host. XDP support ----------- |