| Message ID | 20181213101022.12475-2-jasowang@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | vhost: accelerate metadata access through vmap() | expand |
On Thu, Dec 13, 2018 at 06:10:20PM +0800, Jason Wang wrote: > Use one generic vhost_copy_to_user() instead of two dedicated > accessor. This will simplify the conversion to fine grain accessors. > > Signed-off-by: Jason Wang <jasowang@redhat.com> The reason we did it like this is because it was faster. Want to try benchmarking before we change it? > --- > drivers/vhost/vhost.c | 11 +---------- > 1 file changed, 1 insertion(+), 10 deletions(-) > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > index 3a5f81a66d34..1c54ec1b82f8 100644 > --- a/drivers/vhost/vhost.c > +++ b/drivers/vhost/vhost.c > @@ -2164,16 +2164,7 @@ static int __vhost_add_used_n(struct vhost_virtqueue *vq, > > start = vq->last_used_idx & (vq->num - 1); > used = vq->used->ring + start; > - if (count == 1) { > - if (vhost_put_user(vq, heads[0].id, &used->id)) { > - vq_err(vq, "Failed to write used id"); > - return -EFAULT; > - } > - if (vhost_put_user(vq, heads[0].len, &used->len)) { > - vq_err(vq, "Failed to write used len"); > - return -EFAULT; > - } > - } else if (vhost_copy_to_user(vq, used, heads, count * sizeof *used)) { > + if (vhost_copy_to_user(vq, used, heads, count * sizeof *used)) { > vq_err(vq, "Failed to write used"); > return -EFAULT; > } > -- > 2.17.1
On 2018/12/14 上午3:41, Michael S. Tsirkin wrote: > On Thu, Dec 13, 2018 at 06:10:20PM +0800, Jason Wang wrote: >> Use one generic vhost_copy_to_user() instead of two dedicated >> accessor. This will simplify the conversion to fine grain accessors. >> >> Signed-off-by: Jason Wang <jasowang@redhat.com> > > The reason we did it like this is because it was faster. > Want to try benchmarking before we change it? Faster is a good side effect of such conversion. Otherwise we need two new fine grain memory accessor. But, anyway, I can test its impact. Thanks > >> --- >> drivers/vhost/vhost.c | 11 +---------- >> 1 file changed, 1 insertion(+), 10 deletions(-) >> >> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c >> index 3a5f81a66d34..1c54ec1b82f8 100644 >> --- a/drivers/vhost/vhost.c >> +++ b/drivers/vhost/vhost.c >> @@ -2164,16 +2164,7 @@ static int __vhost_add_used_n(struct vhost_virtqueue *vq, >> >> start = vq->last_used_idx & (vq->num - 1); >> used = vq->used->ring + start; >> - if (count == 1) { >> - if (vhost_put_user(vq, heads[0].id, &used->id)) { >> - vq_err(vq, "Failed to write used id"); >> - return -EFAULT; >> - } >> - if (vhost_put_user(vq, heads[0].len, &used->len)) { >> - vq_err(vq, "Failed to write used len"); >> - return -EFAULT; >> - } >> - } else if (vhost_copy_to_user(vq, used, heads, count * sizeof *used)) { >> + if (vhost_copy_to_user(vq, used, heads, count * sizeof *used)) { >> vq_err(vq, "Failed to write used"); >> return -EFAULT; >> } >> -- >> 2.17.1
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 3a5f81a66d34..1c54ec1b82f8 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -2164,16 +2164,7 @@ static int __vhost_add_used_n(struct vhost_virtqueue *vq, start = vq->last_used_idx & (vq->num - 1); used = vq->used->ring + start; - if (count == 1) { - if (vhost_put_user(vq, heads[0].id, &used->id)) { - vq_err(vq, "Failed to write used id"); - return -EFAULT; - } - if (vhost_put_user(vq, heads[0].len, &used->len)) { - vq_err(vq, "Failed to write used len"); - return -EFAULT; - } - } else if (vhost_copy_to_user(vq, used, heads, count * sizeof *used)) { + if (vhost_copy_to_user(vq, used, heads, count * sizeof *used)) { vq_err(vq, "Failed to write used"); return -EFAULT; }
Use one generic vhost_copy_to_user() instead of two dedicated accessor. This will simplify the conversion to fine grain accessors. Signed-off-by: Jason Wang <jasowang@redhat.com> --- drivers/vhost/vhost.c | 11 +---------- 1 file changed, 1 insertion(+), 10 deletions(-)