Manoj Vishwanathan wrote:
> From: Willem de Bruijn <will...@google.com>
>
> The virtchannel control queue is lossy to avoid deadlock. Ensure that
> no losses occur in practice. Detect a full queue, when overflows may
> have happened.
>
> In practice, virtchnl is synchronous currenty and messages generally
> take a single slot. Using up anywhere near the full ring is not
> expected.
>
> Tested: Running several traffic tests and no logs seen in the dmesg
>
> Signed-off-by: Willem de Bruijn <will...@google.com>
This was an internal patch. Not really intended for upstream as is.
> Signed-off-by: Manoj Vishwanathan <manojvi...@google.com>
> ---
> drivers/net/ethernet/intel/idpf/idpf_virtchnl.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/drivers/net/ethernet/intel/idpf/idpf_virtchnl.c
> b/drivers/net/ethernet/intel/idpf/idpf_virtchnl.c
> index 07239afb285e..1852836d81e4 100644
> --- a/drivers/net/ethernet/intel/idpf/idpf_virtchnl.c
> +++ b/drivers/net/ethernet/intel/idpf/idpf_virtchnl.c
> @@ -218,6 +218,15 @@ static int idpf_mb_clean(struct idpf_adapter *adapter)
> if (err)
> goto err_kfree;
>
> + /* Warn if messages may have been dropped */
> + if (num_q_msg == IDPF_DFLT_MBX_Q_LEN) {
> + static atomic_t mbx_full = ATOMIC_INIT(0);
> + int cnt;
> +
> + cnt = atomic_inc_return(&mbx_full);
> + net_warn_ratelimited("%s: ctlq full (%d)\n", __func__, cnt);
A single static variable across all devices.
If this indeed should never happen, a WARN_ON_ONCE will suffice.
