On Thu, Oct 24, 2024 at 3:41 PM Michael Chan
Hi Michael,
Thank you so much for the review!
<michael.chan@xxxxxxxxxxxx> wrote:
>
> On Tue, Oct 22, 2024 at 9:24 AM Taehee Yoo <ap420073@xxxxxxxxx> wrote:
> >
> > The bnxt_en driver supports rx-copybreak, but it couldn't be set by
> > userspace. Only the default value(256) has worked.
> > This patch makes the bnxt_en driver support following command.
> > `ethtool --set-tunable <devname> rx-copybreak <value> ` and
> > `ethtool --get-tunable <devname> rx-copybreak`.
> >
> > Reviewed-by: Brett Creeley <brett.creeley@xxxxxxx>
> > Tested-by: Stanislav Fomichev <sdf@xxxxxxxxxxx>
> > Signed-off-by: Taehee Yoo <ap420073@xxxxxxxxx>
> > ---
> >
> > v4:
> > - Remove min rx-copybreak value.
> > - Add Review tag from Brett.
> > - Add Test tag from Stanislav.
> >
> > v3:
> > - Update copybreak value after closing nic and before opening nic when
> > the device is running.
> >
> > v2:
> > - Define max/vim rx_copybreak value.
> >
> > drivers/net/ethernet/broadcom/bnxt/bnxt.c | 23 +++++----
> > drivers/net/ethernet/broadcom/bnxt/bnxt.h | 5 +-
> > .../net/ethernet/broadcom/bnxt/bnxt_ethtool.c | 48 ++++++++++++++++++-
> > 3 files changed, 65 insertions(+), 11 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
> > index bda3742d4e32..0f5fe9ba691d 100644
> > --- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
> > +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
>
> > @@ -4510,7 +4513,8 @@ void bnxt_set_ring_params(struct bnxt *bp)
> > ALIGN(max(NET_SKB_PAD, XDP_PACKET_HEADROOM), 8) -
> > SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
> > } else {
> > - rx_size = SKB_DATA_ALIGN(BNXT_RX_COPY_THRESH + NET_IP_ALIGN);
> > + rx_size = SKB_DATA_ALIGN(bp->rx_copybreak +
> > + NET_IP_ALIGN);
>
> When rx_copybreak is 0 or very small, rx_size will be very small and
> will be a problem. We need rx_size to be big enough to contain the
> packet header, so rx_size cannot be below some minimum (256?).
>
> > rx_space = rx_size + NET_SKB_PAD +
> > SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
> > }
> > @@ -6424,8 +6428,8 @@ static int bnxt_hwrm_vnic_set_hds(struct bnxt *bp, struct bnxt_vnic_info *vnic)
> > VNIC_PLCMODES_CFG_REQ_FLAGS_HDS_IPV6);
> > req->enables |=
> > cpu_to_le32(VNIC_PLCMODES_CFG_REQ_ENABLES_HDS_THRESHOLD_VALID);
> > - req->jumbo_thresh = cpu_to_le16(bp->rx_copy_thresh);
> > - req->hds_threshold = cpu_to_le16(bp->rx_copy_thresh);
> > + req->jumbo_thresh = cpu_to_le16(bp->rx_copybreak);
> > + req->hds_threshold = cpu_to_le16(bp->rx_copybreak);
>
> Similarly, these thresholds should not go to 0 when rx_copybreak becomes small.
>
> > }
> > req->vnic_id = cpu_to_le32(vnic->fw_vnic_id);
> > return hwrm_req_send(bp, req);
>
> > @@ -4769,7 +4813,7 @@ static int bnxt_run_loopback(struct bnxt *bp)
> > cpr = &rxr->bnapi->cp_ring;
> > if (bp->flags & BNXT_FLAG_CHIP_P5_PLUS)
> > cpr = rxr->rx_cpr;
> > - pkt_size = min(bp->dev->mtu + ETH_HLEN, bp->rx_copy_thresh);
> > + pkt_size = min(bp->dev->mtu + ETH_HLEN, bp->rx_copybreak);
>
> The loopback test will also not work if rx_copybreak is very small. I
> think we should always use 256 bytes for the loopback test packet
> size. Thanks.
>
> > skb = netdev_alloc_skb(bp->dev, pkt_size);
> > if (!skb)
> > return -ENOMEM;
I tested `ethtool -t eth0` and I checked it fails if rx-copybreak is too
small. Sorry for missing that.
I think we can use max(BNXT_DEFAULT_RX_COPYBREAK,
bp->rx_copybreak) for both cases.
I tested it, it works well.
So I will use that if you are okay!
Thank you so much,
Tahee Yoo
