From: Stephen Hemminger [mailto:step...@networkplumber.org] Sent: Thursday, April 16, 2015 1:48 PM To: Ouyang, Changchun Cc: dev at dpdk.org Subject: Re: [dpdk-dev] [PATCH 4/5] virtio: fix ring size negotiation
No warning is needed, it just works. I know it works, but the upper user don?t know the descriptor number is reduced. I concern it is not so user-friendly here. On Wed, Apr 15, 2015 at 8:39 PM, Ouyang, Changchun <changchun.ouyang at intel.com<mailto:changchun.ouyang at intel.com>> wrote: > -----Original Message----- > From: dev [mailto:dev-bounces at dpdk.org<mailto:dev-bounces at dpdk.org>] On > Behalf Of Stephen > Hemminger > Sent: Wednesday, April 15, 2015 11:20 PM > To: dev at dpdk.org<mailto:dev at dpdk.org> > Subject: [dpdk-dev] [PATCH 4/5] virtio: fix ring size negotiation > > This fixes another of the issues with running virtio on non-KVM > envirionments. For example, Google Compute Engine reports a ring size of > 16K. > > If guest virtio requests more slots than available then the queue should just I suspect 'more' here should be 'less'? > be initialized to the smaller value. > > Conversely, if the number of descriptors requested exceeds the virtio host > queue size, then just silently use the smaller host size. > > Signed-off-by: Stephen Hemminger <stephen at > networkplumber.org<mailto:stephen at networkplumber.org>> > --- > lib/librte_pmd_virtio/virtio_ethdev.c | 18 +++++++++++++----- > 1 file changed, 13 insertions(+), 5 deletions(-) > > diff --git a/lib/librte_pmd_virtio/virtio_ethdev.c > b/lib/librte_pmd_virtio/virtio_ethdev.c > index 3cb9c6a..db0232e 100644 > --- a/lib/librte_pmd_virtio/virtio_ethdev.c > +++ b/lib/librte_pmd_virtio/virtio_ethdev.c > @@ -267,13 +267,21 @@ int virtio_dev_queue_setup(struct rte_eth_dev > *dev, > if (vq_size == 0) { > PMD_INIT_LOG(ERR, "%s: virtqueue does not exist", > __func__); > return -EINVAL; > - } else if (!rte_is_power_of_2(vq_size)) { > + } > + > + if (!rte_is_power_of_2(vq_size)) { > PMD_INIT_LOG(ERR, "%s: virtqueue size is not powerof 2", > __func__); > return -EINVAL; > - } else if (nb_desc != vq_size) { > - PMD_INIT_LOG(ERR, "Warning: nb_desc(%d) is not equal to > vq size (%d), fall to vq size", > - nb_desc, vq_size); > - nb_desc = vq_size; > + } > + > + if (nb_desc < vq_size) { > + if (!rte_is_power_of_2(nb_desc)) { > + PMD_INIT_LOG(ERR, > + "nb_desc(%u) size is not powerof 2", > + nb_desc); > + return -EINVAL; > + } > + vq_size = nb_desc; Don't we need a warning when nb_desc > vq_size? > } > > if (queue_type == VTNET_RQ) { > -- > 2.1.4
