On Fri, 17 Aug 2007 16:04:09 -0700 (PDT) David Miller <[EMAIL PROTECTED]> wrote:
> From: Stephen Hemminger <[EMAIL PROTECTED]> > Date: Fri, 17 Aug 2007 15:40:22 -0700 > > > Compile tested only!!! > > Obviously. The first loopback transmit is guarenteed to crash. That is fixable. > > Fix optimization of netdev_priv() lost by the addition of multiqueue. > > Move the variable size subqueues to after the constant size priv area. > > > > When putting back the old netdev_priv() code, I tried to make it > > clearer by using roundup() and ALIGN() macros. > > > > --- a/include/linux/netdevice.h 2007-08-17 12:08:51.000000000 -0400 > > +++ b/include/linux/netdevice.h 2007-08-17 12:48:03.000000000 -0400 > > @@ -575,16 +575,15 @@ struct net_device > > > > /* The TX queue control structures */ > > unsigned int egress_subqueue_count; > > - struct net_device_subqueue egress_subqueue[1]; > > + struct net_device_subqueue *egress_subqueue; > > }; > > This just trades off the dev->priv dereference for a > dev->egress_subqueue dereference. I bet they occur about equally in > the data paths, at least on transmit. The subqueue is only referenced in start/stop queue and that only happens once per packet on normal tx, and only if multiqueue is used. The existing multiqueue penalizes all devices, not just multiqueue devices. > And this also breaks loopback again, which uses a static struct netdev > in the kernel image, it doesn't use alloc_netdev(), so egress_subqueue > of loopback will be NULL. That can be overcome. -- Stephen Hemminger <[EMAIL PROTECTED]> - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
