[PATCH RFC] vhost: optimize interrupt enable/disable
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: 2011-07-19 15:04:39
Also in:
kvm, lkml
Subsystem:
the rest, virtio host (vhost) · Maintainers:
Linus Torvalds, "Michael S. Tsirkin", Jason Wang
As we now only update used ring after enabling the backend, we can write flags with __put_user: as that's done on data path, it matters. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> --- It seems an obvious optimization so I queued this up already. drivers/vhost/vhost.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index c16d225..c14c42b 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c@@ -998,7 +998,7 @@ int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log, static int vhost_update_used_flags(struct vhost_virtqueue *vq) { void __user *used; - if (put_user(vq->used_flags, &vq->used->flags) < 0) + if (__put_user(vq->used_flags, &vq->used->flags) < 0) return -EFAULT; if (unlikely(vq->log_used)) { /* Make sure the flag is seen before log. */
@@ -1016,7 +1016,7 @@ static int vhost_update_used_flags(struct vhost_virtqueue *vq) static int vhost_update_avail_event(struct vhost_virtqueue *vq, u16 avail_event) { - if (put_user(vq->avail_idx, vhost_avail_event(vq))) + if (__put_user(vq->avail_idx, vhost_avail_event(vq))) return -EFAULT; if (unlikely(vq->log_used)) { void __user *used;
--
1.7.5.53.gc233e