From: Eric Dumazet <eric.dumazet@gmail.com>
To: Marcin Wojtas <mw@semihalf.com>
Cc: linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, netdev@vger.kernel.org,
davem@davemloft.net, linux@arm.linux.org.uk,
sebastian.hesselbarth@gmail.com, andrew@lunn.ch,
jason@lakedaemon.net, thomas.petazzoni@free-electrons.com,
gregory.clement@free-electrons.com, nadavh@marvell.com,
alior@marvell.com, simon.guinot@sequanux.org,
nitroshift@yahoo.com, jaz@semihalf.com
Subject: Re: [PATCH net-next 1/2] net: mvneta: add xmit_more support
Date: Tue, 13 Sep 2016 07:33:02 -0700 [thread overview]
Message-ID: <1473777182.18970.118.camel@edumazet-glaptop3.roam.corp.google.com> (raw)
In-Reply-To: <1473750006-21199-2-git-send-email-mw@semihalf.com>
On Tue, 2016-09-13 at 09:00 +0200, Marcin Wojtas wrote:
> From: Simon Guinot <simon.guinot@sequanux.org>
>
> Basing on xmit_more flag of the skb, TX descriptors can be concatenated
> before flushing. This commit delay Tx descriptor flush if the queue is
> running and if there is more skb's to send.
>
> Signed-off-by: Simon Guinot <simon.guinot@sequanux.org>
> ---
> drivers/net/ethernet/marvell/mvneta.c | 11 ++++++++---
> 1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
> index d41c28d..b9dccea 100644
> --- a/drivers/net/ethernet/marvell/mvneta.c
> +++ b/drivers/net/ethernet/marvell/mvneta.c
> @@ -512,6 +512,7 @@ struct mvneta_tx_queue {
> * descriptor ring
> */
> int count;
> + int pending;
> int tx_stop_threshold;
> int tx_wake_threshold;
>
> @@ -802,8 +803,9 @@ static void mvneta_txq_pend_desc_add(struct mvneta_port *pp,
> /* Only 255 descriptors can be added at once ; Assume caller
> * process TX desriptors in quanta less than 256
> */
Hi Marcin
Well, given the above comment, and fact that MVNETA_MAX_TXD == 532, it
looks like you might add a bug if more than 256 skb are given to your
ndo_start_xmit() with skb->xmit_more = 1
I therefore suggest you make sure it does not happen.
txq->pending += frags;
if (!skb->xmit_more ||
txq->pending > 256 - MVNETA_MAX_SKB_DESCS ||
netif_xmit_stopped(nq))
mvneta_txq_pend_desc_add(pp, txq)
WARNING: multiple messages have this Message-ID (diff)
From: eric.dumazet@gmail.com (Eric Dumazet)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH net-next 1/2] net: mvneta: add xmit_more support
Date: Tue, 13 Sep 2016 07:33:02 -0700 [thread overview]
Message-ID: <1473777182.18970.118.camel@edumazet-glaptop3.roam.corp.google.com> (raw)
In-Reply-To: <1473750006-21199-2-git-send-email-mw@semihalf.com>
On Tue, 2016-09-13 at 09:00 +0200, Marcin Wojtas wrote:
> From: Simon Guinot <simon.guinot@sequanux.org>
>
> Basing on xmit_more flag of the skb, TX descriptors can be concatenated
> before flushing. This commit delay Tx descriptor flush if the queue is
> running and if there is more skb's to send.
>
> Signed-off-by: Simon Guinot <simon.guinot@sequanux.org>
> ---
> drivers/net/ethernet/marvell/mvneta.c | 11 ++++++++---
> 1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
> index d41c28d..b9dccea 100644
> --- a/drivers/net/ethernet/marvell/mvneta.c
> +++ b/drivers/net/ethernet/marvell/mvneta.c
> @@ -512,6 +512,7 @@ struct mvneta_tx_queue {
> * descriptor ring
> */
> int count;
> + int pending;
> int tx_stop_threshold;
> int tx_wake_threshold;
>
> @@ -802,8 +803,9 @@ static void mvneta_txq_pend_desc_add(struct mvneta_port *pp,
> /* Only 255 descriptors can be added at once ; Assume caller
> * process TX desriptors in quanta less than 256
> */
Hi Marcin
Well, given the above comment, and fact that MVNETA_MAX_TXD == 532, it
looks like you might add a bug if more than 256 skb are given to your
ndo_start_xmit() with skb->xmit_more = 1
I therefore suggest you make sure it does not happen.
txq->pending += frags;
if (!skb->xmit_more ||
txq->pending > 256 - MVNETA_MAX_SKB_DESCS ||
netif_xmit_stopped(nq))
mvneta_txq_pend_desc_add(pp, txq)
next prev parent reply other threads:[~2016-09-13 14:33 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-13 7:00 [PATCH net-next 0/2] mvneta xmit_more and bql support Marcin Wojtas
2016-09-13 7:00 ` Marcin Wojtas
2016-09-13 7:00 ` [PATCH net-next 1/2] net: mvneta: add xmit_more support Marcin Wojtas
2016-09-13 7:00 ` Marcin Wojtas
2016-09-13 14:33 ` Eric Dumazet [this message]
2016-09-13 14:33 ` Eric Dumazet
2016-09-13 14:42 ` Eric Dumazet
2016-09-13 14:42 ` Eric Dumazet
2016-09-13 7:00 ` [PATCH net-next 2/2] net: mvneta: add BQL support Marcin Wojtas
2016-09-13 7:00 ` Marcin Wojtas
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