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authorShachar Raindel <shacharr@microsoft.com>2021-03-13 02:45:27 +0300
committerDavid S. Miller <davem@davemloft.net>2021-03-15 00:32:37 +0300
commitbd49fea7586b9d39a38846e9ef4ac056e4eb6e59 (patch)
tree2f24bccd2826e7b7080342dbeaf9e40c73a29c3c /Documentation/networking/device_drivers
parent0f88e6f35b314500ba4c2f7d62c4598bf2c1229b (diff)
downloadlinux-bd49fea7586b9d39a38846e9ef4ac056e4eb6e59.tar.xz
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.rst14
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
-----------