Hi Gavin,

On 1/10/19 9:19 AM, Gavin Hu (Arm Technology China) wrote:


-----Original Message-----
From: dev <dev-boun...@dpdk.org> On Behalf Of Ilya Maximets
Sent: Wednesday, January 9, 2019 10:50 PM
To: dev@dpdk.org; Maxime Coquelin <maxime.coque...@redhat.com>;
Michael S . Tsirkin <m...@redhat.com>; Xiao Wang
<xiao.w.w...@intel.com>
Cc: Tiwei Bie <tiwei....@intel.com>; Zhihong Wang
<zhihong.w...@intel.com>; jfreim...@redhat.com; Jason Wang
<jasow...@redhat.com>; xiaolong...@intel.com;
alejandro.luc...@netronome.com; Ilya Maximets
<i.maxim...@samsung.com>
Subject: [dpdk-dev] [PATCH v3 2/3] net/virtio: update memory ordering
comment for vq notify

We're not using io ports in case of modern device even on IA.
Also, this comment useless for other architectures.

Agree, it should be architecture neutral.


Signed-off-by: Ilya Maximets <i.maxim...@samsung.com>
---
  drivers/net/virtio/virtqueue.h | 9 ++++-----
  1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/net/virtio/virtqueue.h b/drivers/net/virtio/virtqueue.h
index dffa03669..53aeac238 100644
--- a/drivers/net/virtio/virtqueue.h
+++ b/drivers/net/virtio/virtqueue.h
@@ -437,14 +437,13 @@ virtqueue_kick_prepare_packed(struct virtqueue
*vq)
        return flags != RING_EVENT_FLAGS_DISABLE;
  }

+/*
+ * virtqueue_kick_prepare*() or the virtio_wmb() should be called
+ * before this function to be sure that all the data is visible to vhost.
+ */

C11 _atomic APIs are preferred for new code, other than wmb or rmb,  could you 
work on that?

Thanks for the review.
-rc2 deadline is today, so I may apply this series as is if no reply
from Ilya today. If a change is agreed, it could be made on top for
-rc3.

Regards,
Maxime
  static inline void
  virtqueue_notify(struct virtqueue *vq)
  {
-       /*
-        * Ensure updated avail->idx is visible to host.
-        * For virtio on IA, the notificaiton is through io port operation
-        * which is a serialization instruction itself.
-        */
        VTPCI_OPS(vq->hw)->notify_queue(vq->hw, vq);
  }

--
2.17.1

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