Hi Jisheng,
On ven., févr. 17 2017, Jisheng Zhang <jszh...@marvell.com> wrote:
> In hot code path mvneta_rx_hwbm(), the rx_desc->status is read twice.
> The rx_desc is allocated by dma_alloc_coherent, it's uncacheable if
> the device isn't cache-coherent, reading from uncached memory is
> fairly slow. So reuse the read out rx_status to avoid the second
> reading from uncached memory.
>
> Signed-off-by: Jisheng Zhang <jszh...@marvell.com>
> Suggested-by: Arnd Bergmann <a...@arndb.de>
This one is OK and I didn't see a regression:
Tested-by: Gregory CLEMENT <gregory.clem...@free-electrons.com>
Gregory
> ---
> drivers/net/ethernet/marvell/mvneta.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/ethernet/marvell/mvneta.c
> b/drivers/net/ethernet/marvell/mvneta.c
> index 61dd4462411c..06df72b8da85 100644
> --- a/drivers/net/ethernet/marvell/mvneta.c
> +++ b/drivers/net/ethernet/marvell/mvneta.c
> @@ -313,8 +313,8 @@
> ((addr >= txq->tso_hdrs_phys) && \
> (addr < txq->tso_hdrs_phys + txq->size * TSO_HEADER_SIZE))
>
> -#define MVNETA_RX_GET_BM_POOL_ID(rxd) \
> - (((rxd)->status & MVNETA_RXD_BM_POOL_MASK) >> MVNETA_RXD_BM_POOL_SHIFT)
> +#define MVNETA_RX_GET_BM_POOL_ID(status) \
> + (((status) & MVNETA_RXD_BM_POOL_MASK) >> MVNETA_RXD_BM_POOL_SHIFT)
>
> struct mvneta_statistic {
> unsigned short offset;
> @@ -1900,7 +1900,7 @@ static void mvneta_rxq_drop_pkts(struct mvneta_port *pp,
> for (i = 0; i < rx_done; i++) {
> struct mvneta_rx_desc *rx_desc =
> mvneta_rxq_next_desc_get(rxq);
> - u8 pool_id = MVNETA_RX_GET_BM_POOL_ID(rx_desc);
> + u8 pool_id = MVNETA_RX_GET_BM_POOL_ID(rx_desc->status);
> struct mvneta_bm_pool *bm_pool;
>
> bm_pool = &pp->bm_priv->bm_pools[pool_id];
> @@ -2075,7 +2075,7 @@ static int mvneta_rx_hwbm(struct mvneta_port *pp, int
> rx_todo,
> rx_bytes = rx_desc->data_size - (ETH_FCS_LEN + MVNETA_MH_SIZE);
> data = (u8 *)(uintptr_t)rx_desc->buf_cookie;
> phys_addr = rx_desc->buf_phys_addr;
> - pool_id = MVNETA_RX_GET_BM_POOL_ID(rx_desc);
> + pool_id = MVNETA_RX_GET_BM_POOL_ID(rx_status);
> bm_pool = &pp->bm_priv->bm_pools[pool_id];
>
> if (!mvneta_rxq_desc_is_first_last(rx_status) ||
> --
> 2.11.0
>
--
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com
