From: Joyce Kong <joyce.kong@arm.com>
To: maxime.coquelin@redhat.com, chenbo.xia@intel.com,
honnappa.nagarahalli@arm.com, ruifeng.wang@arm.com
Cc: dev@dpdk.org, nd@arm.com
Subject: [dpdk-dev] [PATCH v1 5/8] vhost: relax full barriers for desc flags
Date: Mon, 21 Dec 2020 23:50:30 +0800 [thread overview]
Message-ID: <20201221155033.6771-6-joyce.kong@arm.com> (raw)
In-Reply-To: <20201221155033.6771-1-joyce.kong@arm.com>
Relax the full read barrier to one-way barrier for desc flags in
packed vring.
Signed-off-by: Joyce Kong <joyce.kong@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
---
lib/librte_vhost/virtio_net.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
index c912ae354..b779034dc 100644
--- a/lib/librte_vhost/virtio_net.c
+++ b/lib/librte_vhost/virtio_net.c
@@ -222,8 +222,9 @@ vhost_flush_dequeue_shadow_packed(struct virtio_net *dev,
struct vring_used_elem_packed *used_elem = &vq->shadow_used_packed[0];
vq->desc_packed[vq->shadow_last_used_idx].id = used_elem->id;
- rte_smp_wmb();
- vq->desc_packed[vq->shadow_last_used_idx].flags = used_elem->flags;
+ /* desc flags is the synchronization point for virtio packed vring */
+ __atomic_store_n(&vq->desc_packed[vq->shadow_last_used_idx].flags,
+ used_elem->flags, __ATOMIC_RELEASE);
vhost_log_cache_used_vring(dev, vq, vq->shadow_last_used_idx *
sizeof(struct vring_packed_desc),
--
2.29.2
next prev parent reply other threads:[~2020-12-21 15:52 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-21 15:50 [dpdk-dev] [PATCH v1 0/8] replace smp barriers in vhost with C11 atomic Joyce Kong
2020-12-21 15:50 ` [dpdk-dev] [PATCH v1 1/8] examples/vhost: relax memory ordering when enqueue/dequeue Joyce Kong
2021-01-07 16:33 ` Maxime Coquelin
2020-12-21 15:50 ` [dpdk-dev] [PATCH v1 2/8] examples/vhost_blk: replace smp with thread fence Joyce Kong
2021-01-07 16:35 ` Maxime Coquelin
2020-12-21 15:50 ` [dpdk-dev] [PATCH v1 3/8] vhost: remove unnecessary smp barrier for desc flags Joyce Kong
2021-01-07 16:38 ` Maxime Coquelin
2020-12-21 15:50 ` [dpdk-dev] [PATCH v1 4/8] vhost: remove unnecessary smp barrier for avail idx Joyce Kong
2021-01-07 16:43 ` Maxime Coquelin
2020-12-21 15:50 ` Joyce Kong [this message]
2021-01-07 16:45 ` [dpdk-dev] [PATCH v1 5/8] vhost: relax full barriers for desc flags Maxime Coquelin
2020-12-21 15:50 ` [dpdk-dev] [PATCH v1 6/8] vhost: relax full barriers for used idx Joyce Kong
2021-01-07 16:46 ` Maxime Coquelin
2020-12-21 15:50 ` [dpdk-dev] [PATCH v1 7/8] vhost: replace smp with thread fence for packed vring Joyce Kong
2021-01-07 17:06 ` Maxime Coquelin
2020-12-21 15:50 ` [dpdk-dev] [PATCH v1 8/8] vhost: replace smp with thread fence for control path Joyce Kong
2021-01-07 17:15 ` Maxime Coquelin
2021-01-08 9:16 ` [dpdk-dev] [PATCH v1 0/8] replace smp barriers in vhost with C11 atomic Maxime Coquelin
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