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| author | Michael S. Tsirkin <mst@redhat.com> | 2010-05-20 16:24:48 +0300 |
|---|---|---|
| committer | Kevin O'Connor <kevin@koconnor.net> | 2010-05-26 20:51:44 -0400 |
| commit | bfe4d6044c579e4b66566d10b4e25f3297f6c4ab (patch) | |
| tree | b783159cf1b04002b43ea0641f2a81d83e2f7d8b /src/virtio-ring.c | |
| parent | bb68591e7169f9acdfb9625073ceab5f367613f0 (diff) | |
| download | seabios-bfe4d6044c579e4b66566d10b4e25f3297f6c4ab.tar.gz | |
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>
Diffstat (limited to 'src/virtio-ring.c')
| -rw-r--r-- | src/virtio-ring.c | 4 |
1 files changed, 1 insertions, 3 deletions
diff --git a/src/virtio-ring.c b/src/virtio-ring.c index 75656889..493d8b5e 100644 --- a/src/virtio-ring.c +++ b/src/virtio-ring.c @@ -143,12 +143,10 @@ void vring_kick(unsigned int ioaddr, struct vring_virtqueue *vq, int num_added) { struct vring *vr = &vq->vring; struct vring_avail *avail = GET_FLATPTR(vr->avail); - struct vring_used *used = GET_FLATPTR(vq->vring.used); wmb(); SET_FLATPTR(avail->idx, GET_FLATPTR(avail->idx) + num_added); mb(); - if (!(GET_FLATPTR(used->flags) & VRING_USED_F_NO_NOTIFY)) - vp_notify(ioaddr, GET_FLATPTR(vq->queue_index)); + vp_notify(ioaddr, GET_FLATPTR(vq->queue_index)); } |