On Wed, Dec 06, 2017 at 03:55:49PM +0200, Victor Kaplansky wrote:
> When performing live migration or memory hot-plugging,
> the changes to the device and vrings made by message handler
> done independently from vring usage by PMD threads.
>
> This causes for example segfauls during live-migration
> with MQ enable, but in general virtually any request
> sent by qemu changing the state of device can cause
> problems.
>
> These patches fixes all above issues by adding a spinlock
> to every vring and requiring message handler to start operation
> only after ensuring that all PMD threads related to the divece
> are out of critical section accessing the vring data.
>
> Each vring has its own lock in order to not create contention
> between PMD threads of different vrings and to prevent
> performance degradation by scaling queue pair number.
Hi,
Thanks for the patch! Firstly, I didn't see your SoB.
I'm also more interested to know do you see any performance penalty?
> ---
> lib/librte_vhost/vhost.h | 1 +
> lib/librte_vhost/vhost_user.c | 44
> +++++++++++++++++++++++++++++++++++++++++++
> lib/librte_vhost/virtio_net.c | 8 ++++++++
> 3 files changed, 53 insertions(+)
>
> diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
> index 1cc81c17..812aeccd 100644
> --- a/lib/librte_vhost/vhost.h
> +++ b/lib/librte_vhost/vhost.h
> @@ -137,6 +137,7 @@ struct vhost_virtqueue {
> TAILQ_HEAD(, vhost_iotlb_entry) iotlb_list;
> int iotlb_cache_nr;
> TAILQ_HEAD(, vhost_iotlb_entry) iotlb_pending_list;
> + rte_spinlock_t active_lock;
The indentation is broken.
> } __rte_cache_aligned;
> @@ -1356,6 +1361,8 @@ rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
> if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
> vhost_user_iotlb_rd_unlock(vq);
>
> + rte_spinlock_unlock(&vq->active_lock);
Ditto.
--yliu
