[v2,1/2] lib/ethdev: replace full barrier with relaxed barrier

Message ID 20201013162537.24029-1-honnappa.nagarahalli@arm.com
State New
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Series
  • [v2,1/2] lib/ethdev: replace full barrier with relaxed barrier
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Commit Message

Honnappa Nagarahalli Oct. 13, 2020, 4:25 p.m.
From: Phil Yang <phil.yang@arm.com>


While registering the call back functions full write barrier
can be replaced with one-way write barrier.

Signed-off-by: Phil Yang <phil.yang@arm.com>

Signed-off-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>

Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>

Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>

---
v2 - no change

 lib/librte_ethdev/rte_ethdev.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

-- 
2.17.1

Comments

Ferruh Yigit Oct. 14, 2020, 4:36 p.m. | #1
On 10/13/2020 5:25 PM, Honnappa Nagarahalli wrote:
> From: Phil Yang <phil.yang@arm.com>

> 

> While registering the call back functions full write barrier

> can be replaced with one-way write barrier.

> 

> Signed-off-by: Phil Yang <phil.yang@arm.com>

> Signed-off-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>

> Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>

> Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>


Series applied to dpdk-next-net/main, thanks.

Patch

diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c
index 7858ad5f1..59a41c07f 100644
--- a/lib/librte_ethdev/rte_ethdev.c
+++ b/lib/librte_ethdev/rte_ethdev.c
@@ -26,7 +26,6 @@ 
 #include <rte_eal.h>
 #include <rte_per_lcore.h>
 #include <rte_lcore.h>
-#include <rte_atomic.h>
 #include <rte_branch_prediction.h>
 #include <rte_common.h>
 #include <rte_mempool.h>
@@ -4527,8 +4526,12 @@  rte_eth_add_first_rx_callback(uint16_t port_id, uint16_t queue_id,
 	rte_spinlock_lock(&rte_eth_rx_cb_lock);
 	/* Add the callbacks at first position */
 	cb->next = rte_eth_devices[port_id].post_rx_burst_cbs[queue_id];
-	rte_smp_wmb();
-	rte_eth_devices[port_id].post_rx_burst_cbs[queue_id] = cb;
+	/* Stores to cb->fn, cb->param and cb->next should complete before
+	 * cb is visible to data plane threads.
+	 */
+	__atomic_store_n(
+		&rte_eth_devices[port_id].post_rx_burst_cbs[queue_id],
+		cb, __ATOMIC_RELEASE);
 	rte_spinlock_unlock(&rte_eth_rx_cb_lock);
 
 	return cb;