similar to: [PATCH] virtio_ring: fix packed ring event may missing

On Tue, Oct 22, 2019 at 01:10:04AM +0800, Marvin Liu wrote: > When callback is delayed, virtio expect that vhost will kick when > rolling over event offset. Recheck should be taken as used index may > exceed event offset between status check and driver event update. > > However, it is possible that flags was not modified if descriptors are > chained or in_order feature was

On 2019/10/24 ??11:26, Liu, Yong wrote: > >> -----Original Message----- >> From: Jason Wang [mailto:jasowang at redhat.com] >> Sent: Tuesday, October 22, 2019 9:06 PM >> To: Liu, Yong <yong.liu at intel.com>; mst at redhat.com; Bie, Tiwei >> <tiwei.bie at intel.com> >> Cc: virtualization at lists.linux-foundation.org >> Subject: Re: [PATCH]

From: Marvin Liu <yong.liu at intel.com> When VIRTIO_F_RING_EVENT_IDX is negotiated, virtio devices can use virtqueue_enable_cb_delayed_packed to reduce the number of device interrupts. At the moment, this is the case for virtio-net when the napi_tx module parameter is set to false. In this case, the virtio driver selects an event offset and expects that the device will send a

On 2019/10/22 ??1:10, Marvin Liu wrote: > When callback is delayed, virtio expect that vhost will kick when > rolling over event offset. Recheck should be taken as used index may > exceed event offset between status check and driver event update. > > However, it is possible that flags was not modified if descriptors are > chained or in_order feature was negotiated. So flags at

On 2019/10/22 ??2:48, Liu, Yong wrote: > Hi Jason, > My answers are inline. > >> -----Original Message----- >> From: Jason Wang [mailto:jasowang at redhat.com] >> Sent: Tuesday, October 22, 2019 10:45 AM >> To: Liu, Yong <yong.liu at intel.com>; mst at redhat.com; Bie, Tiwei >> <tiwei.bie at intel.com> >> Cc: virtualization at

On Tue, Oct 22, 2019 at 01:10:04AM +0800, Marvin Liu wrote: > When callback is delayed, virtio expect that vhost will kick when > rolling over event offset. Recheck should be taken as used index may > exceed event offset between status check and driver event update. > > However, it is possible that flags was not modified if descriptors are > chained or in_order feature was

On Wed, Jul 11, 2018 at 10:27:10AM +0800, Tiwei Bie wrote: > This commit introduces the EVENT_IDX support in packed ring. > > Signed-off-by: Tiwei Bie <tiwei.bie at intel.com> Besides the usual comment about hard-coded constants like <<15: does this actually do any good for performance? We don't have to if we do not want to. > --- > drivers/virtio/virtio_ring.c |

On 2018?06?05? 15:40, Tiwei Bie wrote: > static bool virtqueue_enable_cb_delayed_packed(struct virtqueue *_vq) > { > struct vring_virtqueue *vq = to_vvq(_vq); > + u16 bufs, used_idx, wrap_counter; > > START_USE(vq); > > /* We optimistically turn back on interrupts, then check if there was > * more to do. */ > + /* Depending on the

On 2018?05?16? 16:37, Tiwei Bie wrote: > This commit introduces the event idx support in > packed ring. > > Signed-off-by: Tiwei Bie <tiwei.bie at intel.com> > --- > drivers/virtio/virtio_ring.c | 75 +++++++++++++++++++++++++++++++++--- > 1 file changed, 70 insertions(+), 5 deletions(-) > > diff --git a/drivers/virtio/virtio_ring.c

On 2018?05?16? 16:37, Tiwei Bie wrote: > This commit introduces the event idx support in > packed ring. > > Signed-off-by: Tiwei Bie <tiwei.bie at intel.com> > --- > drivers/virtio/virtio_ring.c | 75 +++++++++++++++++++++++++++++++++--- > 1 file changed, 70 insertions(+), 5 deletions(-) > > diff --git a/drivers/virtio/virtio_ring.c

This commit introduces the EVENT_IDX support in packed ring. Signed-off-by: Tiwei Bie <tiwei.bie at intel.com> --- drivers/virtio/virtio_ring.c | 73 ++++++++++++++++++++++++++++++++---- 1 file changed, 65 insertions(+), 8 deletions(-) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index cb833a82054b..4b3f9e1a3cab 100644 --- a/drivers/virtio/virtio_ring.c +++

This commit introduces the EVENT_IDX support in packed ring. Signed-off-by: Tiwei Bie <tiwei.bie at intel.com> --- drivers/virtio/virtio_ring.c | 73 ++++++++++++++++++++++++++++++++---- 1 file changed, 65 insertions(+), 8 deletions(-) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index f317b485ba54..f79a1e17f7d1 100644 --- a/drivers/virtio/virtio_ring.c +++

On 2018?04?25? 13:15, Tiwei Bie wrote: > This commit introduces the event idx support in packed > ring. This feature is temporarily disabled, because the > implementation in this patch may not work as expected, > and some further discussions on the implementation are > needed, e.g. do we have to check the wrap counter when > checking whether a kick is needed? > >

On Wed, Jul 11, 2018 at 10:27:09AM +0800, Tiwei Bie wrote: > This commit introduces the support (without EVENT_IDX) for > packed ring. > > Signed-off-by: Tiwei Bie <tiwei.bie at intel.com> > --- > drivers/virtio/virtio_ring.c | 495 ++++++++++++++++++++++++++++++++++- > 1 file changed, 487 insertions(+), 8 deletions(-) > > diff --git

On 2018?04?25? 13:15, Tiwei Bie wrote: > This commit introduces the event idx support in packed > ring. This feature is temporarily disabled, because the > implementation in this patch may not work as expected, > and some further discussions on the implementation are > needed, e.g. do we have to check the wrap counter when > checking whether a kick is needed? > >

On 2018?04?25? 13:15, Tiwei Bie wrote: > This commit introduces the event idx support in packed > ring. This feature is temporarily disabled, because the > implementation in this patch may not work as expected, > and some further discussions on the implementation are > needed, e.g. do we have to check the wrap counter when > checking whether a kick is needed? > >

On Wed, May 02, 2018 at 03:28:19PM +0800, Tiwei Bie wrote: > On Wed, May 02, 2018 at 10:51:06AM +0800, Jason Wang wrote: > > On 2018?04?25? 13:15, Tiwei Bie wrote: > > > This commit introduces the event idx support in packed > > > ring. This feature is temporarily disabled, because the > > > implementation in this patch may not work as expected, > > >

On Wed, May 02, 2018 at 03:28:19PM +0800, Tiwei Bie wrote: > On Wed, May 02, 2018 at 10:51:06AM +0800, Jason Wang wrote: > > On 2018?04?25? 13:15, Tiwei Bie wrote: > > > This commit introduces the event idx support in packed > > > ring. This feature is temporarily disabled, because the > > > implementation in this patch may not work as expected, > > >

On Wed, May 02, 2018 at 11:12:55PM +0800, Tiwei Bie wrote: > On Wed, May 02, 2018 at 04:51:01PM +0300, Michael S. Tsirkin wrote: > > On Wed, May 02, 2018 at 03:28:19PM +0800, Tiwei Bie wrote: > > > On Wed, May 02, 2018 at 10:51:06AM +0800, Jason Wang wrote: > > > > On 2018?04?25? 13:15, Tiwei Bie wrote: > > > > > This commit introduces the event idx

On Wed, May 02, 2018 at 11:12:55PM +0800, Tiwei Bie wrote: > On Wed, May 02, 2018 at 04:51:01PM +0300, Michael S. Tsirkin wrote: > > On Wed, May 02, 2018 at 03:28:19PM +0800, Tiwei Bie wrote: > > > On Wed, May 02, 2018 at 10:51:06AM +0800, Jason Wang wrote: > > > > On 2018?04?25? 13:15, Tiwei Bie wrote: > > > > > This commit introduces the event idx