• R
    liquidio: prevent rx queues from getting stalled · ccdd0b4c
    Raghu Vatsavayi 提交于
    This commit has fix for RX traffic issues when we stress test the driver
    with continuous ifconfig up/down under very high traffic conditions.
    
    Reason for the issue is that, in existing liquidio_stop function NAPI is
    disabled even before actual FW/HW interface is brought down via
    send_rx_ctrl_cmd(lio, 0). Between time frame of NAPI disable and actual
    interface down in firmware, firmware continuously enqueues rx traffic to
    host. When interrupt happens for new packets, host irq handler fails in
    scheduling NAPI as the NAPI is already disabled.
    
    After "ifconfig <iface> up", Host re-enables NAPI but cannot schedule it
    until it receives another Rx interrupt. Host never receives Rx interrupt as
    it never cleared the Rx interrupt it received during interface down
    operation. NIC Rx interrupt gets cleared only when Host processes queue and
    clears the queue counts. Above anomaly leads to other issues like packet
    overflow in FW/HW queues, backpressure.
    
    Fix:
    This commit fixes this issue by disabling NAPI only after informing
    firmware to stop queueing packets to host via send_rx_ctrl_cmd(lio, 0).
    send_rx_ctrl_cmd is not visible in the patch as it is already there in the
    code. The DOWN command also waits for any pending packets to be processed
    by NAPI so that the deadlock will not occur.
    Signed-off-by: NRaghu Vatsavayi <raghu.vatsavayi@cavium.com>
    Acked-by: NDerek Chickles <derek.chickles@cavium.com>
    Signed-off-by: NFelix Manlunas <felix.manlunas@cavium.com>
    Signed-off-by: NDavid S. Miller <davem@davemloft.net>
    ccdd0b4c
lio_vf_main.c 67.2 KB