Re: [PATCHv3 1/2] virtio: support layout with avail ring before idx

2010-06-04 Thread Michael S. Tsirkin
On Fri, Jun 04, 2010 at 12:04:57PM +0930, Rusty Russell wrote: On Wed, 2 Jun 2010 12:17:12 am Michael S. Tsirkin wrote: This adds an (unused) option to put available ring before control (avail index, flags), and adds padding between index and flags. This avoids cache line sharing between

Re: [PATCHv3 1/2] virtio: support layout with avail ring before idx

2010-06-04 Thread Rusty Russell
On Fri, 4 Jun 2010 09:12:05 pm Michael S. Tsirkin wrote: On Fri, Jun 04, 2010 at 08:46:49PM +0930, Rusty Russell wrote: I'm uncomfortable with moving a field. We haven't done that before and I wonder what will break with old code. With e.g. my patch, We only do this conditionally when