From: "Michael S. Tsirkin" <mst@redhat.com>
To: Anthony Liguori <anthony@codemonkey.ws>
Cc: Rusty Russell <rusty@rustcorp.com.au>,
qemu-devel@nongnu.org, kvm@vger.kernel.org,
virtualization@lists.linux-foundation.org
Subject: [Qemu-devel] Re: question on virtio
Date: Wed, 5 May 2010 23:59:27 +0300 [thread overview]
Message-ID: <20100505205927.GA7111@redhat.com> (raw)
In-Reply-To: <4BE1C99F.6050205@codemonkey.ws>
On Wed, May 05, 2010 at 02:40:15PM -0500, Anthony Liguori wrote:
> On 05/05/2010 06:09 AM, Michael S. Tsirkin wrote:
>> Hi!
>> I see this in virtio_ring.c:
>>
>> /* Put entry in available array (but don't update avail->idx *
>> until they do sync). */
>>
>> Why is it done this way?
>> It seems that updating the index straight away would be simpler, while
>> this might allow the host to specilatively look up the buffer and handle
>> it, without waiting for the kick.
>>
>
> It should be okay as long as you don't update idx for partial vectors.
>
> Regards,
>
> Anthony Liguori
Sorry, what do you mean by partial vectors here?
next prev parent reply other threads:[~2010-05-05 21:10 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-05 11:09 [Qemu-devel] question on virtio Michael S. Tsirkin
2010-05-05 19:40 ` [Qemu-devel] " Anthony Liguori
2010-05-05 20:59 ` Michael S. Tsirkin [this message]
2010-05-06 1:32 ` Rusty Russell
2010-05-06 16:43 ` [Qemu-devel] " Jamie Lokier
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