From: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
To: Camelia Groza <camelia.groza@nxp.com>
Cc: kuba@kernel.org, davem@davemloft.net, madalin.bucur@oss.nxp.com,
netdev@vger.kernel.org
Subject: Re: [PATCH net 2/3] dpaa_eth: reduce data alignment requirements for the A050385 erratum
Date: Thu, 4 Feb 2021 16:58:03 +0100 [thread overview]
Message-ID: <20210204155803.GC2580@ranger.igk.intel.com> (raw)
In-Reply-To: <6e534e4b2da14bb57331446e950a49f237f979c0.1612275417.git.camelia.groza@nxp.com>
On Tue, Feb 02, 2021 at 07:34:43PM +0200, Camelia Groza wrote:
> The 256 byte data alignment is required for preventing DMA transaction
> splits when crossing 4K page boundaries. Since XDP deals only with page
> sized buffers or less, this restriction isn't needed. Instead, the data
> only needs to be aligned to 64 bytes to prevent DMA transaction splits.
>
> These lessened restrictions can increase performance by widening the pool
> of permitted data alignments and preventing unnecessary realignments.
>
> Fixes: ae680bcbd06a ("dpaa_eth: implement the A050385 erratum workaround for XDP")
> Signed-off-by: Camelia Groza <camelia.groza@nxp.com>
Acked-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
> ---
> drivers/net/ethernet/freescale/dpaa/dpaa_eth.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
> index e1d041c35ad9..78dfa05f6d55 100644
> --- a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
> +++ b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
> @@ -2192,7 +2192,7 @@ static int dpaa_a050385_wa_xdpf(struct dpaa_priv *priv,
> * byte frame headroom. If the XDP program uses all of it, copy the
> * data to a new buffer and make room for storing the backpointer.
> */
> - if (PTR_IS_ALIGNED(xdpf->data, DPAA_A050385_ALIGN) &&
> + if (PTR_IS_ALIGNED(xdpf->data, DPAA_FD_DATA_ALIGNMENT) &&
> xdpf->headroom >= priv->tx_headroom) {
> xdpf->headroom = priv->tx_headroom;
> return 0;
> --
> 2.17.1
>
next prev parent reply other threads:[~2021-02-04 16:14 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-02 17:34 [PATCH net 0/3] dpaa_eth: A050385 erratum workaround fixes under XDP Camelia Groza
2021-02-02 17:34 ` [PATCH net 1/3] dpaa_eth: reserve space for the xdp_frame under the A050385 erratum Camelia Groza
2021-02-04 8:51 ` Maciej Fijalkowski
2021-02-04 11:55 ` Camelia Alexandra Groza
2021-02-02 17:34 ` [PATCH net 2/3] dpaa_eth: reduce data alignment requirements for " Camelia Groza
2021-02-04 15:58 ` Maciej Fijalkowski [this message]
2021-02-02 17:34 ` [PATCH net 3/3] dpaa_eth: try to move the data in place " Camelia Groza
2021-02-04 15:56 ` Maciej Fijalkowski
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