Subject: Re: [net-next RFC V3 PATCH 4/6] tuntap: multiqueue support

From: "Michael S. Tsirkin" <[email-masked]>
Date: Mon, 25 Jun 2012 11:41:51 +0300

On Mon, Jun 25, 2012 at 11:25:53AM +0300, Michael S. Tsirkin wrote:
> On Mon, Jun 25, 2012 at 02:10:18PM +0800, Jason Wang wrote:
> > This patch adds multiqueue support for tap device. This is done by abstracting
> > each queue as a file/socket and allowing multiple sockets to be attached to the
> > tuntap device (an array of tun_file were stored in the tun_struct). Userspace
> > could write and read from those files to do the parallel packet
> > sending/receiving.
> > 
> > Unlike the previous single queue implementation, the socket and device were
> > loosely coupled, each of them were allowed to go away first. In order to let the
> > tx path lockless, netif_tx_loch_bh() is replaced by RCU/NETIF_F_LLTX to
> > synchronize between data path and system call.
> 
> Don't use LLTX/RCU. It's not worth it.

Or maybe we should use LLTX. Need to think about it.
But if yes I'd like a separate patch moving tun to LLTX
and move it always to LLTX. Don't play with LLTX at runtime.

-- 
MST