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 6/8] vhost: relax full barriers for used idx
Date: Mon, 21 Dec 2020 23:50:31 +0800 [thread overview]
Message-ID: <20201221155033.6771-7-joyce.kong@arm.com> (raw)
In-Reply-To: <20201221155033.6771-1-joyce.kong@arm.com>
Used idx can be synchronized by one-way barrier instead of full
write barrier for split vring.
Signed-off-by: Joyce Kong <joyce.kong@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
---
lib/librte_vhost/vdpa.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/lib/librte_vhost/vdpa.c b/lib/librte_vhost/vdpa.c
index ae6fdd24e..99a926a77 100644
--- a/lib/librte_vhost/vdpa.c
+++ b/lib/librte_vhost/vdpa.c
@@ -217,8 +217,8 @@ rte_vdpa_relay_vring_used(int vid, uint16_t qid, void *vring_m)
idx++;
}
- rte_smp_wmb();
- vq->used->idx = idx_m;
+ /* used idx is the synchronization point for the split vring */
+ __atomic_store_n(&vq->used->idx, idx_m, __ATOMIC_RELEASE);
if (dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX))
vring_used_event(s_vring) = idx_m;
--
2.29.2
next prev parent reply other threads:[~2020-12-21 15:53 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 ` [dpdk-dev] [PATCH v1 5/8] vhost: relax full barriers for desc flags Joyce Kong
2021-01-07 16:45 ` Maxime Coquelin
2020-12-21 15:50 ` Joyce Kong [this message]
2021-01-07 16:46 ` [dpdk-dev] [PATCH v1 6/8] vhost: relax full barriers for used idx 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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