From: Jason Wang <jasowang@redhat.com>
To: mst@redhat.com, jasowang@redhat.com, kvm@vger.kernel.org,
virtualization@lists.linux-foundation.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [RFC PATCH V2 1/3] vhost: generalize adding used elem
Date: Fri, 28 Dec 2018 15:55:35 +0800 [thread overview]
Message-ID: <20181228075537.21402-2-jasowang@redhat.com> (raw)
In-Reply-To: <20181228075537.21402-1-jasowang@redhat.com>
Use one generic vhost_copy_to_user() instead of two dedicated
accessor. This will simplify the conversion to fine grain
accessors. About 2% improvement of PPS were seen during vitio-user
txonly test.
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
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 55e5aa662ad5..f179b5ee14c4 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -2174,16 +2174,7 @@ 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
next prev parent reply other threads:[~2018-12-28 7:55 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-28 7:55 [RFC PATCH V2 0/3] vhost: accelerate metadata access through vmap() Jason Wang
2018-12-28 7:55 ` Jason Wang [this message]
2018-12-28 7:55 ` [RFC PATCH V2 2/3] vhost: fine grain userspace memory accessors Jason Wang
2018-12-28 7:55 ` [RFC PATCH V2 3/3] vhost: access vq metadata through kernel virtual address Jason Wang
2018-12-28 19:34 ` David Miller
2018-12-29 12:41 ` Jason Wang
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