On Wed, Jun 10, 2020 at 5:08 PM Michael S. Tsirkin <mst@xxxxxxxxxx> wrote: > > On Wed, Jun 10, 2020 at 04:29:29PM +0200, Eugenio Pérez wrote: > > On Wed, 2020-06-10 at 07:36 -0400, Michael S. Tsirkin wrote: > > > As testing shows no performance change, switch to that now. > > > > > > Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx> > > > Signed-off-by: Eugenio Pérez <eperezma@xxxxxxxxxx> > > > Link: https://lore.kernel.org/r/20200401183118.8334-3-eperezma@xxxxxxxxxx > > > Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx> > > > --- > > > drivers/vhost/test.c | 2 +- > > > drivers/vhost/vhost.c | 318 ++++++++---------------------------------- > > > drivers/vhost/vhost.h | 7 +- > > > 3 files changed, 65 insertions(+), 262 deletions(-) > > > > > > diff --git a/drivers/vhost/test.c b/drivers/vhost/test.c > > > index 0466921f4772..7d69778aaa26 100644 > > > --- a/drivers/vhost/test.c > > > +++ b/drivers/vhost/test.c > > > @@ -119,7 +119,7 @@ static int vhost_test_open(struct inode *inode, struct file *f) > > > dev = &n->dev; > > > vqs[VHOST_TEST_VQ] = &n->vqs[VHOST_TEST_VQ]; > > > n->vqs[VHOST_TEST_VQ].handle_kick = handle_vq_kick; > > > - vhost_dev_init(dev, vqs, VHOST_TEST_VQ_MAX, UIO_MAXIOV, > > > + vhost_dev_init(dev, vqs, VHOST_TEST_VQ_MAX, UIO_MAXIOV + 64, > > > VHOST_TEST_PKT_WEIGHT, VHOST_TEST_WEIGHT, true, NULL); > > > > > > f->private_data = n; > > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > > > index 11433d709651..28f324fd77df 100644 > > > --- a/drivers/vhost/vhost.c > > > +++ b/drivers/vhost/vhost.c > > > @@ -304,6 +304,7 @@ static void vhost_vq_reset(struct vhost_dev *dev, > > > { > > > vq->num = 1; > > > vq->ndescs = 0; > > > + vq->first_desc = 0; > > > vq->desc = NULL; > > > vq->avail = NULL; > > > vq->used = NULL; > > > @@ -372,6 +373,11 @@ static int vhost_worker(void *data) > > > return 0; > > > } > > > > > > +static int vhost_vq_num_batch_descs(struct vhost_virtqueue *vq) > > > +{ > > > + return vq->max_descs - UIO_MAXIOV; > > > +} > > > + > > > static void vhost_vq_free_iovecs(struct vhost_virtqueue *vq) > > > { > > > kfree(vq->descs); > > > @@ -394,6 +400,9 @@ static long vhost_dev_alloc_iovecs(struct vhost_dev *dev) > > > for (i = 0; i < dev->nvqs; ++i) { > > > vq = dev->vqs[i]; > > > vq->max_descs = dev->iov_limit; > > > + if (vhost_vq_num_batch_descs(vq) < 0) { > > > + return -EINVAL; > > > + } > > > vq->descs = kmalloc_array(vq->max_descs, > > > sizeof(*vq->descs), > > > GFP_KERNEL); > > > @@ -1610,6 +1619,7 @@ long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *arg > > > vq->last_avail_idx = s.num; > > > /* Forget the cached index value. */ > > > vq->avail_idx = vq->last_avail_idx; > > > + vq->ndescs = vq->first_desc = 0; > > > > This is not needed if it is done in vhost_vq_set_backend, as far as I can tell. > > > > Actually, maybe it is even better to move `vq->avail_idx = vq->last_avail_idx;` line to vhost_vq_set_backend, it is part > > of the backend "set up" procedure, isn't it? > > > > I tested with virtio_test + batch tests sent in > > https://lkml.kernel.org/lkml/20200418102217.32327-1-eperezma@xxxxxxxxxx/T/. > > Ow did I forget to merge them for rc1? Should I have? Maybe Linus won't > yell to hard at me if I merge them after rc1. > > > > I append here what I'm proposing in case it is clearer this way. > > > > Thanks! > > > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > > index 4d198994e7be..809ad2cd2879 100644 > > --- a/drivers/vhost/vhost.c > > +++ b/drivers/vhost/vhost.c > > @@ -1617,9 +1617,6 @@ long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *arg > > break; > > } > > vq->last_avail_idx = s.num; > > - /* Forget the cached index value. */ > > - vq->avail_idx = vq->last_avail_idx; > > - vq->ndescs = vq->first_desc = 0; > > break; > > case VHOST_GET_VRING_BASE: > > s.index = idx; > > diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h > > index fed36af5c444..f4902dc808e4 100644 > > --- a/drivers/vhost/vhost.h > > +++ b/drivers/vhost/vhost.h > > @@ -258,6 +258,7 @@ static inline void vhost_vq_set_backend(struct vhost_virtqueue *vq, > > void *private_data) > > { > > vq->private_data = private_data; > > + vq->avail_idx = vq->last_avail_idx; > > vq->ndescs = 0; > > vq->first_desc = 0; > > } > > > > Seems like a nice cleanup, though it's harmless right? > Fields ndescs and first_descs are supposed to be updated outside, that was the intention but maybe I forgot to delete it here, not sure. Regarding avail_idx, the whole change has been tested with vhost_test and for vhost needs to have a backend to modify it already so it seems safe to me.
