Re: [PATCH net-next v2] gve: Add RSS cache for non RSS device option scenario

Ziwei Xiao
2025-02-06T06:26:52Z

On Wed, Feb 5, 2025 at 8:28 AM Simon Horman <horms@kernel.org> wrote:
>
> On Tue, Feb 04, 2025 at 01:31:21PM -0800, Jeroen de Borst wrote:
> > From: Ziwei Xiao <ziweixiao@google.com>
> >
> > Not all the devices have the capability for the driver to query for the
> > registered RSS configuration. The driver can discover this by checking
> > the relevant device option during setup. If it cannot, the driver needs
> > to store the RSS config cache and directly return such cache when
> > queried by the ethtool. RSS config is inited when driver probes. Also the
> > default RSS config will be adjusted when there is RX queue count change.
> >
> > At this point, only keys of GVE_RSS_KEY_SIZE and indirection tables of
> > GVE_RSS_INDIR_SIZE are supported.
> >
> > Signed-off-by: Ziwei Xiao <ziweixiao@google.com>
> > Reviewed-by: Harshitha Ramamurthy <hramamurthy@google.com>
> > Reviewed-by: Willem de Bruijn <willemb@google.com>
> > Signed-off-by: Praveen Kaligineedi <pkaligineedi@google.com>
> > Signed-off-by: Jeroen de Borst <jeroend@google.com>
> > ---
> > Changes in v2:
> > - Change to initialize RSS config when the driver is up instead of
> > doing that when the user setting the RSS.(Jakub Kicinski)
> > - Use NL_SET_ERR_MSG_MOD to log errors when there is extack
> > available.(Jakub Kicinski)
> > - Use ethtool_rxfh_indir_default to set default RSS indir
> > table.(Jakub Kicinski)
> > - Adjust the default RSS config when there is RX queue count change to
> > ensure the default RSS config is correct.
> >
> > drivers/net/ethernet/google/gve/gve.h | 16 +++-
> > drivers/net/ethernet/google/gve/gve_adminq.c | 64 ++++++++++---
> > drivers/net/ethernet/google/gve/gve_ethtool.c | 60 ++++++++++--
> > drivers/net/ethernet/google/gve/gve_main.c | 92 ++++++++++++++++++-
> > 4 files changed, 209 insertions(+), 23 deletions(-)
>
> ...
>
> > diff --git a/drivers/net/ethernet/google/gve/gve_ethtool.c b/drivers/net/ethernet/google/gve/gve_ethtool.c
> > index bdfc6e77b2af..efcafc607b2a 100644
> > --- a/drivers/net/ethernet/google/gve/gve_ethtool.c
> > +++ b/drivers/net/ethernet/google/gve/gve_ethtool.c
> > @@ -482,6 +482,7 @@ static int gve_set_channels(struct net_device *netdev,
> > struct ethtool_channels old_settings;
> > int new_tx = cmd->tx_count;
> > int new_rx = cmd->rx_count;
> > + bool reset_rss;
> >
> > gve_get_channels(netdev, &old_settings);
> >
> > @@ -498,16 +499,14 @@ static int gve_set_channels(struct net_device *netdev,
> > return -EINVAL;
> > }
> >
> > - if (!netif_running(netdev)) {
> > - priv->tx_cfg.num_queues = new_tx;
> > - priv->rx_cfg.num_queues = new_rx;
> > - return 0;
> > - }
> > + if (new_rx != priv->rx_cfg.num_queues &&
> > + priv->cache_rss_config && !netif_is_rxfh_configured(netdev))
> > + reset_rss = true;
>
> Hi Jerome,
>
> This is not a full review (which I was working on but ran out of time for now).
> But, if the condition above is not met then reset_rss will be used
> uninitialised below.
>
> Flagged by W=1 build with clang-19.
>
Thank you for pointing that out. Will fix it on the V3 patch.
> >
> > new_tx_cfg.num_queues = new_tx;
> > new_rx_cfg.num_queues = new_rx;
> >
> > - return gve_adjust_queues(priv, new_rx_cfg, new_tx_cfg);
> > + return gve_adjust_queues(priv, new_rx_cfg, new_tx_cfg, reset_rss);
> > }
> >
> > static void gve_get_ringparam(struct net_device *netdev,
>
> ...
>
> --
> pw-bot: cr