> -----Original Message-----
> From: Rong, Leyi <leyi.r...@intel.com>
> Sent: Monday, December 13, 2021 11:03
> To: Bin Zheng <zhengbin.89...@bytedance.com>; dev@dpdk.org
> Cc: Wang, Haiyue <haiyue.w...@intel.com>; lian...@liangbit.com;
> sta...@dpdk.org; jia....@intel.com
> Subject: RE: [PATCH v3] net/ixgbe: add vector Rx parameter check
>
>
> > -----Original Message-----
> > From: Bin Zheng <zhengbin.89...@bytedance.com>
> > Sent: Friday, December 10, 2021 4:22 PM
> > To: dev@dpdk.org
> > Cc: Wang, Haiyue <haiyue.w...@intel.com>; lian...@liangbit.com;
> > sta...@dpdk.org; Rong, Leyi <leyi.r...@intel.com>; Bin Zheng
> > <zhengbin.89...@bytedance.com>; jia....@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....@intel.com
> > Cc: sta...@dpdk.org
> >
> > Signed-off-by: Bin Zheng <zhengbin.89...@bytedance.com>
> > ---
> > drivers/net/ixgbe/ixgbe_rxtx_vec_sse.c | 11 +++++++++++
> > 1 file changed, 11 insertions(+)
> >
>
> Acked-by: Leyi Rong <leyi.r...@intel.com>
Reviewed-by: Haiyue Wang <haiyue.w...@intel.com>
