From: "Michael S. Tsirkin" <mst@redhat.com>
To: Shirley Ma <mashirle@us.ibm.com>
Cc: David Miller <davem@davemloft.net>,
Eric Dumazet <eric.dumazet@gmail.com>,
Avi Kivity <avi@redhat.com>, Arnd Bergmann <arnd@arndb.de>,
netdev@vger.kernel.org, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH V5 4/6 net-next] vhost: vhost TX zero-copy support
Date: Mon, 16 May 2011 23:45:40 +0300 [thread overview]
Message-ID: <20110516204540.GD18148@redhat.com> (raw)
In-Reply-To: <1305574484.3456.30.camel@localhost.localdomain>
> +/* Since we need to keep the order of used_idx as avail_idx, it's possible that
> + * DMA done not in order in lower device driver for some reason. To prevent
> + * used_idx out of order, upend_idx is used to track avail_idx order, done_idx
> + * is used to track used_idx order. Once lower device DMA done, then upend_idx
> + * can move to done_idx.
Could you clarify this please? virtio explicitly allows out of order
completion of requests. Does it simplify code that we try to keep
used index updates in-order? Because if not, this is not
really a requirement.
--
MST
next prev parent reply other threads:[~2011-05-16 20:45 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-16 19:34 [PATCH V5 4/6 net-next] vhost: vhost TX zero-copy support Shirley Ma
2011-05-16 20:45 ` Michael S. Tsirkin [this message]
2011-05-16 20:56 ` Shirley Ma
2011-05-16 21:24 ` Michael S. Tsirkin
2011-05-16 21:30 ` Shirley Ma
2011-05-17 4:31 ` Shirley Ma
2011-05-17 5:55 ` Michael S. Tsirkin
2011-05-17 15:22 ` Shirley Ma
2011-05-17 15:28 ` Michael S. Tsirkin
2011-05-17 15:34 ` Shirley Ma
2011-05-17 20:46 ` [TEST PATCH net-next] vhost: accumulate multiple used and sigal in vhost TX test Shirley Ma
2011-05-17 20:52 ` Michael S. Tsirkin
2011-05-17 20:50 ` [PATCH V5 4/6 net-next] vhost: vhost TX zero-copy support Shirley Ma
2011-05-17 20:58 ` Michael S. Tsirkin
2011-05-17 21:01 ` Shirley Ma
2011-05-17 21:28 ` Michael S. Tsirkin
2011-05-17 22:21 ` Shirley Ma
2011-05-18 5:14 ` Shirley Ma
2011-05-18 6:16 ` [PATCH V6 " Shirley Ma
2011-05-18 8:43 ` Michael S. Tsirkin
2011-05-18 8:32 ` [PATCH V5 " Michael S. Tsirkin
2011-05-18 8:45 ` Michael S. Tsirkin
2011-05-16 21:27 ` Michael S. Tsirkin
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