[PATCH v3] net/ixgbe: add vector Rx parameter check

[Wang, Haiyue]

> -----Original Message-----
> From: Rong, Leyi <leyi.rong at intel.com>
> Sent: Monday, December 13, 2021 11:03
> To: Bin Zheng <zhengbin.89740 at bytedance.com>; dev at dpdk.org
> Cc: Wang, Haiyue <haiyue.wang at intel.com>; liangma at liangbit.com; stable at dpdk.org; jia.guo at intel.com
> Subject: RE: [PATCH v3] net/ixgbe: add vector Rx parameter check
> 
> 
> > -----Original Message-----
> > From: Bin Zheng <zhengbin.89740 at bytedance.com>
> > Sent: Friday, December 10, 2021 4:22 PM
> > To: dev at dpdk.org
> > Cc: Wang, Haiyue <haiyue.wang at intel.com>; liangma at liangbit.com;
> > stable at dpdk.org; Rong, Leyi <leyi.rong at intel.com>; Bin Zheng
> > <zhengbin.89740 at bytedance.com>; jia.guo at intel.com
> > Subject: [PATCH v3] net/ixgbe: add vector Rx parameter check
> >
> > Under the circumstance that `rx_tail` wrap back to zero and the advance speed
> > of `rx_tail` is greater than `rxrearm_start`, `rx_tail` will catch up with
> > `rxrearm_start` and surpass it.
> > This may cause some mbufs be reused by application.
> >
> > So we need to make some restrictions to ensure that  `rx_tail` will not exceed
> > `rxrearm_start`.
> >
> > e.g.
> >
> > RDH: 972 RDT: 991 rxrearm_nb: 991 rxrearm_start: 992 rx_tail: 959
> > RDH: 1004 RDT: 1023 rxrearm_nb: 991 rxrearm_start: 0 rx_tail: 991
> > RDH: 12 RDT: 31 rxrearm_nb: 991 rxrearm_start: 32 rx_tail: 1023
> > RDH: 31 RDT: 63 rxrearm_nb: 960 rxrearm_start: 64 rx_tail: 0
> > RDH: 95 RDT: 95 rxrearm_nb: 1016 rxrearm_start: 96 rx_tail: 88
> > RDH: 95 RDT: 127 rxrearm_nb: 991 rxrearm_start: 128 rx_tail: 95 ...
> > RDH: 908 RDT: 927 rxrearm_nb: 991 rxrearm_start: 928 rx_tail: 895
> > RDH: 940 RDT: 959 rxrearm_nb: 991 rxrearm_start: 960 rx_tail: 927
> > RDH: 980 RDT: 991 rxrearm_nb: 991 rxrearm_start: 992 rx_tail: 959
> > RDH: 991 RDT: 991 rxrearm_nb: 1026 rxrearm_start: 992 rx_tail: 994
> >
> > when `rx_tail` catches up with `rxrearm_start`,
> > 2(994 - 992) mbufs be reused by application !
> >
> > Bugzilla ID: 882
> > Fixes: 5a3cca342417 ("net/ixgbe: fix vector Rx")
> > Cc: jia.guo at intel.com
> > Cc: stable at dpdk.org
> >
> > Signed-off-by: Bin Zheng <zhengbin.89740 at bytedance.com>
> > ---
> >  drivers/net/ixgbe/ixgbe_rxtx_vec_sse.c | 11 +++++++++++
> >  1 file changed, 11 insertions(+)
> >


> 
> Acked-by: Leyi Rong <leyi.rong at intel.com>

Reviewed-by: Haiyue Wang <haiyue.wang at intel.com>