For M2S rings, ring->head is updated by the receiver and eth_memif_rx
function is called in the context of receiving thread. The loads in
the sender do not need to synchronize with its own stores.
Fixes: a2aafb9aa651 ("net/memif: optimize with one-way barrier")
Cc: phil.y...@arm.com
Cc: sta...@dpdk.org
Signed-off-by: Honnappa Nagarahalli <honnappa.nagaraha...@arm.com>
Reviewed-by: Phil Yang <phil.y...@arm.com>
---
drivers/net/memif/rte_eth_memif.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/net/memif/rte_eth_memif.c
b/drivers/net/memif/rte_eth_memif.c
index 435c6345c..1cbb1fd7a 100644
--- a/drivers/net/memif/rte_eth_memif.c
+++ b/drivers/net/memif/rte_eth_memif.c
@@ -405,7 +405,11 @@ eth_memif_rx(void *queue, struct rte_mbuf **bufs, uint16_t
nb_pkts)
refill:
if (type == MEMIF_RING_M2S) {
- head = __atomic_load_n(&ring->head, __ATOMIC_ACQUIRE);
+ /* ring->head is updated by the receiver and this function
+ * is called in the context of receiver thread. The loads in
+ * the receiver do not need to synchronize with its own stores.
+ */
+ head = __atomic_load_n(&ring->head, __ATOMIC_RELAXED);
n_slots = ring_size - head + mq->last_tail;
while (n_slots--) {
--
2.17.1
