Hi Bibo,
On Sat, Apr 22, 2023 at 8:29AM, bibo, mao wrote:
在 2023/4/21 9:12, zhoumin 写道:
On Fri, Apr 7, 2023 at 4:50PM, Min Zhou wrote:
Segmentation fault has been observed while running the
ixgbe_recv_pkts_lro() function to receive packets on the Loongson
3C5000 processor which has 64 cores and 4 NUMA nodes.
Reason is the read ordering of the status and the rest of the
descriptor fields in this function may not be correct on the
LoongArch processor. We should add rte_rmb() to ensure the read
ordering be correct.
We also did the same thing in the ixgbe_recv_pkts() function.
Signed-off-by: Min Zhou <zhou...@loongson.cn>
---
drivers/net/ixgbe/ixgbe_rxtx.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/net/ixgbe/ixgbe_rxtx.c
b/drivers/net/ixgbe/ixgbe_rxtx.c
index c9d6ca9efe..16391a42f9 100644
--- a/drivers/net/ixgbe/ixgbe_rxtx.c
+++ b/drivers/net/ixgbe/ixgbe_rxtx.c
@@ -1823,6 +1823,9 @@ ixgbe_recv_pkts(void *rx_queue, struct
rte_mbuf **rx_pkts,
staterr = rxdp->wb.upper.status_error;
if (!(staterr & rte_cpu_to_le_32(IXGBE_RXDADV_STAT_DD)))
break;
+#if defined(RTE_ARCH_LOONGARCH)
+ rte_rmb();
+#endif
rxd = *rxdp;
Hi Min,
Could you add more detailed analysis aboout the issu? Althrough rxdp
is declared as volatile, which is only in order for compiler. However
some architectures like LoongArch are weak-ordered. For this piece of
code:
1: staterr = rxdp->wb.upper.status_error;
Sentence 1 can be execute after sentence 1, dd indicated that packet
is ready with new value.
2: rxd = *rxdp;
Sentence 2 can be execute first and get old value.
.......Balabala
Regards
Bibo, Mao
Thanks for your kind comments.
I have sent the v2 patch and give the more detailed analysis for the
segmentation fault.
Regards
Min
/*
@@ -2122,6 +2125,9 @@ ixgbe_recv_pkts_lro(void *rx_queue, struct
rte_mbuf **rx_pkts, uint16_t nb_pkts,
if (!(staterr & IXGBE_RXDADV_STAT_DD))
break;
+#if defined(RTE_ARCH_LOONGARCH)
+ rte_rmb();
+#endif
rxd = *rxdp;
PMD_RX_LOG(DEBUG, "port_id=%u queue_id=%u rx_id=%u "
Kindly ping.
Any comments or suggestions will be appreciated.
Min
