• Brenden Blanco's avatar
    net/mlx4_en: add xdp forwarding and data write support · 9ecc2d86
    Brenden Blanco authored
    A user will now be able to loop packets back out of the same port using
    a bpf program attached to xdp hook. Updates to the packet contents from
    the bpf program is also supported.
    
    For the packet write feature to work, the rx buffers are now mapped as
    bidirectional when the page is allocated. This occurs only when the xdp
    hook is active.
    
    When the program returns a TX action, enqueue the packet directly to a
    dedicated tx ring, so as to avoid completely any locking. This requires
    the tx ring to be allocated 1:1 for each rx ring, as well as the tx
    completion running in the same softirq.
    
    Upon tx completion, this dedicated tx ring recycles pages without
    unmapping directly back to the original rx ring. In steady state tx/drop
    workload, effectively 0 page allocs/frees will occur.
    
    In order to separate out the paths between free and recycle, a
    free_tx_desc func pointer is introduced that is optionally updated
    whenever recycle_ring is activated. By default the original free
    function is always initialized.
    Signed-off-by: default avatarBrenden Blanco <bblanco@plumgrid.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    9ecc2d86
en_tx.c 31.7 KB