tree 99110cd4a64dcf09a4357d33bd74fe6c53c083fc
parent 811afeaa3797bdf4eabed286100811b33005c9e0
author Eli Cohen <eli@mellanox.com> 1465506460 +0300
committer David S. Miller <davem@davemloft.net> 1465535187 -0700

net/mlx5e: Fix blue flame quota logic

Blue flame is a latency enhancement feature that allows the driver to
write the packet data directly to the NIC's registers thus making the
read of the packet data from host memory redundant.

We maintain a quota for the blue flame which is reloaded whenever we
identify that the hardware is processing send requests and processes
them fast enough so by the time we post the next send request it was
able to process all the pending ones. This indicates that the hardware
is capable of processing more blue flame requests efficiently. The blue
flame quota is decremented whenever we send using blue flame.

The current code erroneously clears the budget if we did not use blue
flame for the current post send operation and we fix it here.

Fixes: 88a85f99e51f ('net/mlx5e: TX latency optimization to save DMA reads')
Signed-off-by: Eli Cohen <eli@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>