Hi,
On Tue, 11 Dec 2018 13:56:49 +0100 Marcin Wojtas wrote:
> Recent changes in the mvneta driver reworked allocation
> and handling of the ingress buffers to use entire pages.
> Apart from that in SW BM scenario the HW must be informed
> via PRXDQS about the biggest possible incoming buffer
> that can be propagated by RX descriptors.
>
> The BufferSize field was filled according to the MTU-dependent
> pkt_size value. Later change to PAGE_SIZE broke RX operation
> when usin 64K pages, as the field is simply too small.
>
> This patch conditionally limits the value passed to the BufferSize
> of the PRXDQS register, depending on the PAGE_SIZE used.
> On the occasion remove now unused frag_size field of the mvneta_port
> structure.
>
> Fixes: 562e2f467e71 ("net: mvneta: Improve the buffer allocation
> method for SWBM")
IMHO, we'd better revert 562e2f467e71 and 7e47fd84b56bb
The issue commit 562e2f467e71 wants to solve is due to commit 7e47fd84b56bb
It looks a bit wired, to introduce regression then submit another commit(in
the same patch set) solve it
Per my test, after reverting 562e2f467e71 and 7e47fd84b56bb, I can't reproduce
what's claimed in commit 562e2f467e71 -- "With system having a small memory
(around 256MB), the state "cannot allocate memory to refill with new buffer"
is reach pretty quickly."
>
> Signed-off-by: Marcin Wojtas <m...@semihalf.com>
> ---
> drivers/net/ethernet/marvell/mvneta.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/ethernet/marvell/mvneta.c
> b/drivers/net/ethernet/marvell/mvneta.c
> index e5397c8..61b2349 100644
> --- a/drivers/net/ethernet/marvell/mvneta.c
> +++ b/drivers/net/ethernet/marvell/mvneta.c
> @@ -408,7 +408,6 @@ struct mvneta_port {
> struct mvneta_pcpu_stats __percpu *stats;
>
> int pkt_size;
> - unsigned int frag_size;
> void __iomem *base;
> struct mvneta_rx_queue *rxqs;
> struct mvneta_tx_queue *txqs;
> @@ -2905,7 +2904,9 @@ static void mvneta_rxq_hw_init(struct mvneta_port *pp,
> if (!pp->bm_priv) {
> /* Set Offset */
> mvneta_rxq_offset_set(pp, rxq, 0);
> - mvneta_rxq_buf_size_set(pp, rxq, pp->frag_size);
> + mvneta_rxq_buf_size_set(pp, rxq, PAGE_SIZE < SZ_64K ?
> + PAGE_SIZE :
> + MVNETA_RX_BUF_SIZE(pp->pkt_size));
> mvneta_rxq_bm_disable(pp, rxq);
> mvneta_rxq_fill(pp, rxq, rxq->size);
> } else {
> @@ -3760,7 +3761,6 @@ static int mvneta_open(struct net_device *dev)
> int ret;
>
> pp->pkt_size = MVNETA_RX_PKT_SIZE(pp->dev->mtu);
> - pp->frag_size = PAGE_SIZE;
>
> ret = mvneta_setup_rxqs(pp);
> if (ret)
