On Wed, 20 Jan 2021 13:27:59 -0800
Ivan Babrou <i...@cloudflare.com> wrote:
> Without this change the driver tries to allocate too many queues,
> breaching the number of available msi-x interrupts on machines
> with many logical cpus and default adapter settings:
>
> Insufficient resources for 12 XDP event queues (24 other channels, max 32)
>
> Which in turn triggers EINVAL on XDP processing:
>
> sfc 0000:86:00.0 ext0: XDP TX failed (-22)
>
> Signed-off-by: Ivan Babrou <i...@cloudflare.com>
> ---
I guess the patch is good in itself due to available msi-x interrupts.
Per earlier discussion: What will happen if a CPU with an ID higher
than available XDP TX-queues redirect a packet out this driver?
> drivers/net/ethernet/sfc/efx_channels.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/ethernet/sfc/efx_channels.c
> b/drivers/net/ethernet/sfc/efx_channels.c
> index a4a626e9cd9a..1bfeee283ea9 100644
> --- a/drivers/net/ethernet/sfc/efx_channels.c
> +++ b/drivers/net/ethernet/sfc/efx_channels.c
> @@ -17,6 +17,7 @@
> #include "rx_common.h"
> #include "nic.h"
> #include "sriov.h"
> +#include "workarounds.h"
>
> /* This is the first interrupt mode to try out of:
> * 0 => MSI-X
> @@ -137,6 +138,7 @@ static int efx_allocate_msix_channels(struct efx_nic *efx,
> {
> unsigned int n_channels = parallelism;
> int vec_count;
> + int tx_per_ev;
> int n_xdp_tx;
> int n_xdp_ev;
>
> @@ -149,9 +151,9 @@ static int efx_allocate_msix_channels(struct efx_nic *efx,
> * multiple tx queues, assuming tx and ev queues are both
> * maximum size.
> */
> -
> + tx_per_ev = EFX_MAX_EVQ_SIZE / EFX_TXQ_MAX_ENT(efx);
> n_xdp_tx = num_possible_cpus();
> - n_xdp_ev = DIV_ROUND_UP(n_xdp_tx, EFX_MAX_TXQ_PER_CHANNEL);
> + n_xdp_ev = DIV_ROUND_UP(n_xdp_tx, tx_per_ev);
>
> vec_count = pci_msix_vec_count(efx->pci_dev);
> if (vec_count < 0)
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
LinkedIn: http://www.linkedin.com/in/brouer
