> -----Original Message-----
> From: Loftus, Ciara [mailto:ciara.lof...@intel.com]
> Sent: Friday, September 18, 2020 5:27 PM
> To: Li,Rongqing <lirongq...@baidu.com>; dev@dpdk.org
> Cc: sta...@dpdk.org
> Subject: RE: [dpdk-dev] [PATCH] af_xdp: avoid deadlock due to empty fill queue
>
> > when receive packets, it is possible to fail to reserve fill queue,
> > since buffer ring is shared between tx and rx, and maybe not available
> > temporary. at last, both fill queue and rx queue are empty.
> >
> > then kernel side will be unable to receive packets due to empty fill
> > queue, and dpdk will be unable to reserve fill queue because dpdk has
> > not pakcets to receive, at last deadlock will happen
> >
> > so move reserve fill queue before xsk_ring_cons__peek to fix it
> >
> > Signed-off-by: Li RongQing <lirongq...@baidu.com>
>
> Thanks for the fix. I tested and saw no significant performance drop.
>
> Minor: the first line of the commit should read "net/af_xdp: ...."
>
> Acked-by: Ciara Loftus <ciara.lof...@intel.com>
>
> CC-ing stable as I think this fix should be considered for inclusion.
>
> Thanks,
> Ciara
>
Thanks, I will send v2
-Li
> > ---
> > drivers/net/af_xdp/rte_eth_af_xdp.c | 7 ++++---
> > 1 file changed, 4 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/net/af_xdp/rte_eth_af_xdp.c
> > b/drivers/net/af_xdp/rte_eth_af_xdp.c
> > index 7ce4ad04a..2dc9cab27 100644
> > --- a/drivers/net/af_xdp/rte_eth_af_xdp.c
> > +++ b/drivers/net/af_xdp/rte_eth_af_xdp.c
> > @@ -304,6 +304,10 @@ af_xdp_rx_cp(void *queue, struct rte_mbuf **bufs,
> > uint16_t nb_pkts)
> > uint32_t free_thresh = fq->size >> 1;
> > struct rte_mbuf *mbufs[ETH_AF_XDP_RX_BATCH_SIZE];
> >
> > + if (xsk_prod_nb_free(fq, free_thresh) >= free_thresh)
> > + (void)reserve_fill_queue(umem,
> > ETH_AF_XDP_RX_BATCH_SIZE, NULL);
> > +
> > +
> > if (unlikely(rte_pktmbuf_alloc_bulk(rxq->mb_pool, mbufs, nb_pkts) !=
> > 0))
> > return 0;
> >
> > @@ -317,9 +321,6 @@ af_xdp_rx_cp(void *queue, struct rte_mbuf **bufs,
> > uint16_t nb_pkts)
> > goto out;
> > }
> >
> > - if (xsk_prod_nb_free(fq, free_thresh) >= free_thresh)
> > - (void)reserve_fill_queue(umem,
> > ETH_AF_XDP_RX_BATCH_SIZE, NULL);
> > -
> > for (i = 0; i < rcvd; i++) {
> > const struct xdp_desc *desc;
> > uint64_t addr;
> > --
> > 2.16.2
