| Message ID | 20110306113349.GA24333@redhat.com |
|---|---|
| State | Awaiting Upstream, archived |
| Delegated to: | David Miller |
| Headers | show |
From: "Michael S. Tsirkin" <mst@redhat.com> Date: Sun, 6 Mar 2011 13:33:49 +0200 > copy_from_user is pretty high on perf top profile, > replacing it with __copy_from_user helps. > It's also safe because we do access_ok checks during setup. > > Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Is Rusty going to take this or should I? -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Sun, Mar 06, 2011 at 06:03:39PM -0800, David Miller wrote: > From: "Michael S. Tsirkin" <mst@redhat.com> > Date: Sun, 6 Mar 2011 13:33:49 +0200 > > > copy_from_user is pretty high on perf top profile, > > replacing it with __copy_from_user helps. > > It's also safe because we do access_ok checks during setup. > > > > Signed-off-by: Michael S. Tsirkin <mst@redhat.com> > > Is Rusty going to take this or should I? Sorry about not making this clear. I'll give it a day or two for review then put it on the vhost tree myself. Thanks! -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index ade0568..01701b8 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -1153,7 +1153,7 @@ int vhost_get_vq_desc(struct vhost_dev *dev, struct vhost_virtqueue *vq, i, vq->num, head); return -EINVAL; } - ret = copy_from_user(&desc, vq->desc + i, sizeof desc); + ret = __copy_from_user(&desc, vq->desc + i, sizeof desc); if (unlikely(ret)) { vq_err(vq, "Failed to get descriptor: idx %d addr %p\n", i, vq->desc + i);
copy_from_user is pretty high on perf top profile, replacing it with __copy_from_user helps. It's also safe because we do access_ok checks during setup. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> --- drivers/vhost/vhost.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)