Re: [Qemu-devel] [Xen-devel] new barrier type for paravirt (was Re: [PATCH] virtio_ring: use smp_store_mb)

2015-12-21 Thread Stefano Stabellini
On Mon, 21 Dec 2015, David Vrabel wrote: > On 20/12/15 09:25, Michael S. Tsirkin wrote: > > > > I noticed that drivers/xen/xenbus/xenbus_comms.c uses > > full memory barriers to communicate with the other side. > > For example: > > > > /* Must write data /after/ reading the

Re: [Xen-devel] new barrier type for paravirt (was Re: [PATCH] virtio_ring: use smp_store_mb)

2015-12-21 Thread David Vrabel
On 20/12/15 09:25, Michael S. Tsirkin wrote: > > I noticed that drivers/xen/xenbus/xenbus_comms.c uses > full memory barriers to communicate with the other side. > For example: > > /* Must write data /after/ reading the consumer index. * */ > mb(); > >

Re: [Xen-devel] new barrier type for paravirt (was Re: [PATCH] virtio_ring: use smp_store_mb)

2015-12-21 Thread Michael S. Tsirkin
On Mon, Dec 21, 2015 at 10:47:49AM +, David Vrabel wrote: > On 20/12/15 09:25, Michael S. Tsirkin wrote: > > > > I noticed that drivers/xen/xenbus/xenbus_comms.c uses > > full memory barriers to communicate with the other side. > > For example: > > > > /* Must write data