On Mon, 2015-11-02 at 19:31 +0200, Madalin Bucur wrote:
> Allow the selection of the transmission queue based on the CPU id.
Explain why.
>
> Signed-off-by: Madalin Bucur <madalin.bu...@freescale.com>
> ---
> drivers/net/ethernet/freescale/dpaa/Kconfig | 10 ++++++++++
> drivers/net/ethernet/freescale/dpaa/dpaa_eth.c | 3 +++
> drivers/net/ethernet/freescale/dpaa/dpaa_eth.h | 6 ++++++
> drivers/net/ethernet/freescale/dpaa/dpaa_eth_common.c | 8 ++++++++
> drivers/net/ethernet/freescale/dpaa/dpaa_eth_common.h | 4 ++++
> 5 files changed, 31 insertions(+)
>
> diff --git a/drivers/net/ethernet/freescale/dpaa/Kconfig
> b/drivers/net/ethernet/freescale/dpaa/Kconfig
> index 022d5aa..2577aac 100644
> --- a/drivers/net/ethernet/freescale/dpaa/Kconfig
> +++ b/drivers/net/ethernet/freescale/dpaa/Kconfig
> @@ -11,6 +11,16 @@ menuconfig FSL_DPAA_ETH
>
> if FSL_DPAA_ETH
>
> +config FSL_DPAA_ETH_USE_NDO_SELECT_QUEUE
> + bool "Use driver's Tx queue selection mechanism"
> + default y
> + ---help---
> + The DPAA Ethernet driver defines a ndo_select_queue() callback
> for optimal selection
> + of the egress FQ. That will override the XPS support for this
> netdevice.
> + If for whatever reason you want to be in control of the egress FQ
> -to-CPU selection and mapping,
> + or simply don't want to use the driver's ndo_select_queue()
> callback, then unselect this
> + and use the standard XPS support instead.
Is there a use case for needing this to be configurable?
> diff --git a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
> b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
> index 31d55b4..894f1a7 100644
> --- a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
> +++ b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
> @@ -390,6 +390,9 @@ static const struct net_device_ops dpa_private_ops = {
> .ndo_get_stats64 = dpa_get_stats64,
> .ndo_set_mac_address = dpa_set_mac_address,
> .ndo_validate_addr = eth_validate_addr,
> +#ifdef CONFIG_FSL_DPAA_ETH_USE_NDO_SELECT_QUEUE
> + .ndo_select_queue = dpa_select_queue,
> +#endif
> .ndo_change_mtu = dpa_change_mtu,
> .ndo_set_rx_mode = dpa_set_rx_mode,
> .ndo_init = dpa_ndo_init,
> diff --git a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.h
> b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.h
> index 1ba6617..87577cf 100644
> --- a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.h
> +++ b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.h
> @@ -420,9 +420,15 @@ static inline void _dpa_assign_wq(struct dpa_fq *fq)
> }
> }
>
> +#ifdef CONFIG_FSL_DPAA_ETH_USE_NDO_SELECT_QUEUE
> +/* Use in lieu of skb_get_queue_mapping() */
> +#define dpa_get_queue_mapping(skb) \
> + raw_smp_processor_id()
> +#else
> /* Use the queue selected by XPS */
> #define dpa_get_queue_mapping(skb) \
> skb_get_queue_mapping(skb)
> +#endif
Why is this necessary? Shouldn't providing a custom .ndo_select_queue() be
sufficient to ensure that skb_get_queue_mapping() returns the same thing?
And if this goes away, it's just a matter of a function pointer, so if it does
need to be configurable it could be a runtime option.
-Scott
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