similar to: [PATCH -next v2] virtio_net: Avoid loop in virtnet_poll

On Sun, Aug 02, 2020 at 01:56:33PM +0800, Mao Wenan wrote: > The loop may exist if vq->broken is true, > virtqueue_get_buf_ctx_packed or virtqueue_get_buf_ctx_split > will return NULL, so virtnet_poll will reschedule napi to > receive packet, it will lead cpu usage(si) to 100%. > > call trace as below: > virtnet_poll > virtnet_receive > virtqueue_get_buf_ctx >

On 2020/8/2 ??3:44, Mao Wenan wrote: > The loop may exist if vq->broken is true, > virtqueue_get_buf_ctx_packed or virtqueue_get_buf_ctx_split > will return NULL, so virtnet_poll will reschedule napi to > receive packet, it will lead cpu usage(si) to 100%. > > call trace as below: > virtnet_poll > virtnet_receive > virtqueue_get_buf_ctx >

From: Mao Wenan <wenan.mao at linux.alibaba.com> [ Upstream commit 481a0d7422db26fb63e2d64f0652667a5c6d0f3e ] The loop may exist if vq->broken is true, virtqueue_get_buf_ctx_packed or virtqueue_get_buf_ctx_split will return NULL, so virtnet_poll will reschedule napi to receive packet, it will lead cpu usage(si) to 100%. call trace as below: virtnet_poll virtnet_receive

From: Mao Wenan <wenan.mao at linux.alibaba.com> [ Upstream commit 481a0d7422db26fb63e2d64f0652667a5c6d0f3e ] The loop may exist if vq->broken is true, virtqueue_get_buf_ctx_packed or virtqueue_get_buf_ctx_split will return NULL, so virtnet_poll will reschedule napi to receive packet, it will lead cpu usage(si) to 100%. call trace as below: virtnet_poll virtnet_receive

From: Mao Wenan <wenan.mao at linux.alibaba.com> [ Upstream commit 481a0d7422db26fb63e2d64f0652667a5c6d0f3e ] The loop may exist if vq->broken is true, virtqueue_get_buf_ctx_packed or virtqueue_get_buf_ctx_split will return NULL, so virtnet_poll will reschedule napi to receive packet, it will lead cpu usage(si) to 100%. call trace as below: virtnet_poll virtnet_receive

From: Mao Wenan <wenan.mao at linux.alibaba.com> [ Upstream commit 481a0d7422db26fb63e2d64f0652667a5c6d0f3e ] The loop may exist if vq->broken is true, virtqueue_get_buf_ctx_packed or virtqueue_get_buf_ctx_split will return NULL, so virtnet_poll will reschedule napi to receive packet, it will lead cpu usage(si) to 100%. call trace as below: virtnet_poll virtnet_receive

From: Mao Wenan <wenan.mao at linux.alibaba.com> [ Upstream commit 481a0d7422db26fb63e2d64f0652667a5c6d0f3e ] The loop may exist if vq->broken is true, virtqueue_get_buf_ctx_packed or virtqueue_get_buf_ctx_split will return NULL, so virtnet_poll will reschedule napi to receive packet, it will lead cpu usage(si) to 100%. call trace as below: virtnet_poll virtnet_receive

From: Mao Wenan <wenan.mao at linux.alibaba.com> [ Upstream commit 481a0d7422db26fb63e2d64f0652667a5c6d0f3e ] The loop may exist if vq->broken is true, virtqueue_get_buf_ctx_packed or virtqueue_get_buf_ctx_split will return NULL, so virtnet_poll will reschedule napi to receive packet, it will lead cpu usage(si) to 100%. call trace as below: virtnet_poll virtnet_receive

From: Mao Wenan <wenan.mao at linux.alibaba.com> [ Upstream commit 481a0d7422db26fb63e2d64f0652667a5c6d0f3e ] The loop may exist if vq->broken is true, virtqueue_get_buf_ctx_packed or virtqueue_get_buf_ctx_split will return NULL, so virtnet_poll will reschedule napi to receive packet, it will lead cpu usage(si) to 100%. call trace as below: virtnet_poll virtnet_receive

This commit introduces the support for creating packed ring. All split ring specific functions are added _split suffix. Some necessary stubs for packed ring are also added. Signed-off-by: Tiwei Bie <tiwei.bie at intel.com> --- drivers/virtio/virtio_ring.c | 801 +++++++++++++++++++++++------------ include/linux/virtio_ring.h | 8 +- 2 files changed, 546 insertions(+), 263 deletions(-)

This commit introduces the support for creating packed ring. All split ring specific functions are added _split suffix. Some necessary stubs for packed ring are also added. Signed-off-by: Tiwei Bie <tiwei.bie at intel.com> --- drivers/virtio/virtio_ring.c | 801 +++++++++++++++++++++++------------ include/linux/virtio_ring.h | 8 +- 2 files changed, 546 insertions(+), 263 deletions(-)

On Fri, Jun 02, 2023 at 05:22:01PM +0800, Xuan Zhuo wrote: > Under the premapped mode, the driver needs to unmap the DMA address > after receiving the buffer. The virtio core records the DMA address, > so the driver needs a way to get the dma info from the virtio core. > > A straightforward approach is to pass an array to the virtio core when > calling virtqueue_get_buf().

Since commit 39e6c8208d7b ("net: solve a NAPI race") napi has been able to be rescheduled within napi_complete_done() even in non-busypoll case, but virtnet_poll() always enabled interrupts before complete, and when napi was rescheduled within napi_complete_done() it did not disable interrupts. This caused more interrupts when event idx is disabled. According to commit cbdadbbf0c79

Since commit 39e6c8208d7b ("net: solve a NAPI race") napi has been able to be rescheduled within napi_complete_done() even in non-busypoll case, but virtnet_poll() always enabled interrupts before complete, and when napi was rescheduled within napi_complete_done() it did not disable interrupts. This caused more interrupts when event idx is disabled. According to commit cbdadbbf0c79

On Thu, Dec 07, 2017 at 01:15:15PM +0900, Toshiaki Makita wrote: > Since commit 39e6c8208d7b ("net: solve a NAPI race") napi has been able > to be rescheduled within napi_complete_done() even in non-busypoll case, > but virtnet_poll() always enabled interrupts before complete, and when > napi was rescheduled within napi_complete_done() it did not disable > interrupts. >

On 2017?12?07? 13:09, Michael S. Tsirkin wrote: > On Thu, Dec 07, 2017 at 01:15:15PM +0900, Toshiaki Makita wrote: >> Since commit 39e6c8208d7b ("net: solve a NAPI race") napi has been able >> to be rescheduled within napi_complete_done() even in non-busypoll case, >> but virtnet_poll() always enabled interrupts before complete, and when >> napi was rescheduled

On 2017?12?07? 13:09, Michael S. Tsirkin wrote: > On Thu, Dec 07, 2017 at 01:15:15PM +0900, Toshiaki Makita wrote: >> Since commit 39e6c8208d7b ("net: solve a NAPI race") napi has been able >> to be rescheduled within napi_complete_done() even in non-busypoll case, >> but virtnet_poll() always enabled interrupts before complete, and when >> napi was rescheduled

is the below same as what I posted or different? how? On Sat, Mar 25, 2023 at 06:56:33PM +0800, Albert Huang wrote: > in virtio_net, if we disable the napi_tx, when we triger a tx interrupt, > the vq->event_triggered will be set to true. It will no longer be set to > false. Unless we explicitly call virtqueue_enable_cb_delayed or > virtqueue_enable_cb_prepare. > > If we

On 2018?04?01? 22:12, Tiwei Bie wrote: > Hello everyone, > > This RFC implements packed ring support for virtio driver. > > The code was tested with DPDK vhost (testpmd/vhost-PMD) implemented > by Jens at http://dpdk.org/ml/archives/dev/2018-January/089417.html > Minor changes are needed for the vhost code, e.g. to kick the guest. > > TODO: > - Refinements and bug

On 2018?04?01? 22:12, Tiwei Bie wrote: > Hello everyone, > > This RFC implements packed ring support for virtio driver. > > The code was tested with DPDK vhost (testpmd/vhost-PMD) implemented > by Jens at http://dpdk.org/ml/archives/dev/2018-January/089417.html > Minor changes are needed for the vhost code, e.g. to kick the guest. > > TODO: > - Refinements and bug