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From: "Ouyang, Changchun" <changchun.ouyang@intel.com>
To: "Stephen Hemminger (stephen@networkplumber.org)"
 <stephen@networkplumber.org>, "Xie, Huawei" <huawei.xie@intel.com>,
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Thread-Topic: [dpdk-dev] [PATCH v2 02/24] virtio: Use weaker barriers
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Date: Tue, 27 Jan 2015 08:04:44 +0000
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Subject: Re: [dpdk-dev] [PATCH v2 02/24] virtio: Use weaker barriers
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Hi Stephen,
Although it is original code logic,=20
But we can move vq_update_avail_idx(rxvq) into if block to resolve it.
What do you think of it?

Thanks
Changchun

-----Original Message-----
From: Xie, Huawei=20
Sent: Tuesday, January 27, 2015 3:57 PM
To: Ouyang, Changchun; dev@dpdk.org
Cc: Stephen Hemminger (stephen@networkplumber.org)
Subject: RE: [dpdk-dev] [PATCH v2 02/24] virtio: Use weaker barriers

>-------if (likely(nb_enqueued)) {
>------->-------virtio_wmb();
>------->-------if (unlikely(virtqueue_kick_prepare(rxvq))) {
>------->------->-------virtqueue_notify(rxvq);
>------->------->-------PMD_RX_LOG(DEBUG, "Notified\n");
>------->-------}
>-------}
>-------vq_update_avail_idx(rxvq);


Two confuses for the modification here:

1.
why notify host without updating avail idx?
Will this cause potential deadlock?

2.
Why update avail index even no packets are enqueued?