Re: [dpdk-dev] [PATCH] net/mlx4: verify RSS supports num Rx Qs being used

[Matan Azrad <matan@mellanox.com>]

Hi

> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Matan Azrad
> Sent: Thursday, July 26, 2018 5:36 PM
> To: Mordechay Haimovsky <motih@mellanox.com>
> Cc: dev@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH] net/mlx4: verify RSS supports num Rx Qs being
> used
> 
> Hi Moti
> 
> Small comment below.
> 
> From: Mordechay Haimovsky
> > This patch verifies that the number of Rx queues configured for RSS is
> > supported by the device hardware.
> > RSS support in mlx4 requires contiguous chunk of QPs to be reserved,
> > there is a hardware limitation on the amount of contiguous QPs which
> > is reported by the hardware. Ignoring this value will cause Rx queues creation
> to fail.
> >
> > Signed-off-by: Moti Haimovsky <motih@mellanox.com>
> > ---
> >  drivers/net/mlx4/mlx4.c     | 3 +++
> >  drivers/net/mlx4/mlx4.h     | 1 +
> >  drivers/net/mlx4/mlx4_rxq.c | 6 ++++++
> >  3 files changed, 10 insertions(+)
> >
> > diff --git a/drivers/net/mlx4/mlx4.c b/drivers/net/mlx4/mlx4.c index
> > c67d2c0..defc0d4 100644
> > --- a/drivers/net/mlx4/mlx4.c
> > +++ b/drivers/net/mlx4/mlx4.c
> > @@ -673,6 +673,9 @@ struct mlx4_conf {
> >  						   &device_attr_ex);
> >  		DEBUG("supported RSS hash fields mask: %016" PRIx64,
> >  		      priv->hw_rss_sup);
> > +		priv->hw_rss_max_qps =
> > +
> > 	device_attr_ex.rss_caps.max_rwq_indirection_table_size;
> > +		DEBUG("MAX RSS queues %d", priv->hw_rss_max_qps);
> >  		priv->hw_fcs_strip = !!(device_attr_ex.raw_packet_caps &
> >
> > 	IBV_RAW_PACKET_CAP_SCATTER_FCS);
> >  		DEBUG("FCS stripping toggling is %ssupported", diff --git
> > a/drivers/net/mlx4/mlx4.h b/drivers/net/mlx4/mlx4.h index
> > 89d8c38..e6fb934
> > 100644
> > --- a/drivers/net/mlx4/mlx4.h
> > +++ b/drivers/net/mlx4/mlx4.h
> > @@ -95,6 +95,7 @@ struct priv {
> >  	uint32_t hw_fcs_strip:1; /**< FCS stripping toggling is supported. */
> >  	uint32_t tso:1; /**< Transmit segmentation offload is supported. */
> >  	uint32_t tso_max_payload_sz; /**< Max supported TSO payload size.
> > */
> > +	uint32_t hw_rss_max_qps; /**< Max Rx Queues supported by RSS. */
> >  	uint64_t hw_rss_sup; /**< Supported RSS hash fields (Verbs format). */
> >  	struct rte_intr_handle intr_handle; /**< Port interrupt handle. */
> >  	struct mlx4_drop *drop; /**< Shared resources for drop flow rules.
> > */ diff --git a/drivers/net/mlx4/mlx4_rxq.c
> > b/drivers/net/mlx4/mlx4_rxq.c index 0cd9560..e8bef1d 100644
> > --- a/drivers/net/mlx4/mlx4_rxq.c
> > +++ b/drivers/net/mlx4/mlx4_rxq.c
> > @@ -338,6 +338,12 @@ struct mlx4_rss *
> >
> >  	if (priv->rss_init)
> >  		return 0;
> > +	if (priv->dev->data->nb_rx_queues > priv->hw_rss_max_qps) {
> > +		ERROR("RSS does not support more than %d queues",
> > +		      priv->hw_rss_max_qps);
> > +		rte_errno = EINVAL;
> 
> What's about E2BIG ?


My mistake,
The description of E2BIG related to the argument list and not generally for too big parameters,
so no need to change the EINVAL.

> > +		return -rte_errno;
> > +	}
> >  	/* Prepare range for RSS contexts before creating the first WQ. */
> >  	ret = mlx4_glue->dv_set_context_attr
> >  		(priv->ctx,
> > --
> > 1.8.3.1
> 
> Besides that;
> Acked-by: Matan Azrad <matan@mellanox.com>