virtio: remove NO_NOTIFY optimization
authorMichael S. Tsirkin <mst@redhat.com>
Thu, 20 May 2010 13:24:48 +0000 (16:24 +0300)
committerKevin O'Connor <kevin@koconnor.net>
Thu, 27 May 2010 00:51:44 +0000 (20:51 -0400)
commitbfe4d6044c579e4b66566d10b4e25f3297f6c4ab
treeb783159cf1b04002b43ea0641f2a81d83e2f7d8b
parentbb68591e7169f9acdfb9625073ceab5f367613f0
virtio: remove NO_NOTIFY optimization

NO_NOTIFY is an optimization to reduce the number of exits,
but using it requires careful synchronization with host,
forcing read/write ordering for the CPU. Otherwise we
risk not kicking a host when it is waiting for more buffers,
resulting in a deadlock.

Let's just always kick, it's way simpler.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>
src/virtio-ring.c