On Mon, Dec 21, 2015 at 7:41 PM, Yuanhan Liu <yuanhan.liu at linux.intel.com> wrote:
> On Fri, Dec 18, 2015 at 10:01:25AM -0800, Rich Lane wrote: > > I'm using the vhost callbacks and struct virtio_net with the vhost PMD > in a few > > ways: > > Rich, thanks for the info! > > > > > 1. new_device/destroy_device: Link state change (will be covered by the > link > > status interrupt). > > 2. new_device: Add first queue to datapath. > > I'm wondering why vring_state_changed() is not used, as it will also be > triggered at the beginning, when the default queue (the first queue) is > enabled. > Turns out I'd misread the code and it's already using the vring_state_changed callback for the first queue. Not sure if this is intentional but vring_state_changed is called for the first queue before new_device. > > 3. vring_state_changed: Add/remove queue to datapath. > > 4. destroy_device: Remove all queues (vring_state_changed is not called > when > > qemu is killed). > > I had a plan to invoke vring_state_changed() to disable all vrings > when destroy_device() is called. > That would be good. > > 5. new_device and struct virtio_net: Determine NUMA node of the VM. > > You can get the 'struct virtio_net' dev from all above callbacks. > 1. Link status interrupt. > > To vhost pmd, new_device()/destroy_device() equals to the link status > interrupt, where new_device() is a link up, and destroy_device() is link > down(). > > > > 2. New queue_state_changed callback. Unlike vring_state_changed this > should > > cover the first queue at new_device and removal of all queues at > > destroy_device. > > As stated above, vring_state_changed() should be able to do that, except > the one on destroy_device(), which is not done yet. > > > 3. Per-queue or per-device NUMA node info. > > You can query the NUMA node info implicitly by get_mempolicy(); check > numa_realloc() at lib/librte_vhost/virtio-net.c for reference. > Your suggestions are exactly how my application is already working. I was commenting on the proposed changes to the vhost PMD API. I would prefer to use RTE_ETH_EVENT_INTR_LSC and rte_eth_dev_socket_id for consistency with other NIC drivers, instead of these vhost-specific hacks. The queue state change callback is the one new API that needs to be added because normal NICs don't have this behavior. You could add another rte_eth_event_type for the queue state change callback, and pass the queue ID, RX/TX direction, and enable bit through cb_arg. The application would never need to touch struct virtio_net.
