On Wed, 16 Oct 2019 15:46:15 +0200 Maxime Coquelin <maxime.coque...@redhat.com> wrote:
> On 10/16/19 3:32 PM, Ilya Maximets wrote: > > On 16.10.2019 13:13, Maxime Coquelin wrote: > >> > >> > >> On 10/15/19 8:59 PM, Flavio Leitner wrote: > >>> The rte_vhost_dequeue_burst supports two ways of dequeuing data. > >>> If the data fits into a buffer, then all data is copied and a > >>> single linear buffer is returned. Otherwise it allocates > >>> additional mbufs and chains them together to return a multiple > >>> segments mbuf. > >>> > >>> While that covers most use cases, it forces applications that > >>> need to work with larger data sizes to support multiple segments > >>> mbufs. The non-linear characteristic brings complexity and > >>> performance implications to the application. > >>> > >>> To resolve the issue, add support to attach external buffer > >>> to a pktmbuf and let the host provide during registration if > >>> attaching an external buffer to pktmbuf is supported and if > >>> only linear buffer are supported. > >>> > >>> Signed-off-by: Flavio Leitner <f...@sysclose.org> > >>> --- > >>> doc/guides/prog_guide/vhost_lib.rst | 35 +++++++++ > >>> lib/librte_vhost/rte_vhost.h | 4 + > >>> lib/librte_vhost/socket.c | 22 ++++++ > >>> lib/librte_vhost/vhost.c | 22 ++++++ > >>> lib/librte_vhost/vhost.h | 4 + > >>> lib/librte_vhost/virtio_net.c | 109 > >>> ++++++++++++++++++++++++---- 6 files changed, 182 insertions(+), > >>> 14 deletions(-) > >>> > >>> - Changelog: > >>> v5: > >>> - fixed to destroy mutex if incompatible flags > >>> v4: > >>> - allow to use pktmbuf if there is exact space > >>> - removed log message if the buffer is too big > >>> - fixed the length to include align padding > >>> - free allocated buf if shinfo fails > >>> v3: > >>> - prevent the new features to be used with zero copy > >>> - fixed sizeof() usage > >>> - fixed log msg indentation > >>> - removed/replaced asserts > >>> - used the correct virt2iova function > >>> - fixed the patch's title > >>> - OvS PoC code: > >>> https://github.com/fleitner/ovs/tree/rte_malloc-v3 > >>> v2: > >>> - Used rte_malloc() instead of another mempool as suggested > >>> by Shahaf. > >>> - Added the documentation section. > >>> - Using driver registration to negotiate the features. > >>> - OvS PoC code: > >>> > >>> https://github.com/fleitner/ovs/commit/8fc197c40b1d4fda331686a7b919e9e2b670dda7 > >>> > >> > >> Applied to dpdk-next-virtio/master. > > > > Thanks Maxime, > > > > But can we return back the mbuf allocation failure message? > > Good point, I missed it. > > > I mean: > > > > diff --git a/lib/librte_vhost/virtio_net.c > > b/lib/librte_vhost/virtio_net.c index 66f0c7206..f8af4e0b3 100644 > > --- a/lib/librte_vhost/virtio_net.c > > +++ b/lib/librte_vhost/virtio_net.c > > @@ -1354,8 +1354,11 @@ virtio_dev_pktmbuf_alloc(struct virtio_net > > *dev, struct rte_mempool *mp, > > { > > struct rte_mbuf *pkt = rte_pktmbuf_alloc(mp); > > > > - if (unlikely(pkt == NULL)) > > + if (unlikely(pkt == NULL)) { > > + RTE_LOG(ERR, VHOST_DATA, > > + "Failed to allocate memory for mbuf.\n"); > > return NULL; > > + } > > > > if (rte_pktmbuf_tailroom(pkt) >= data_len) > > return pkt; > > --- > > > > It's a hard failure that highlights some significant issues with > > memory pool size or a mbuf leak. > > I agree, we need this error message. If it runs out of memory and there are many packets coming, then it will flood the logs. Maybe we could use something to report in a more moderated way, for example: diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c index da69ab1db..b1572b3a4 100644 --- a/lib/librte_vhost/virtio_net.c +++ b/lib/librte_vhost/virtio_net.c @@ -1354,8 +1354,14 @@ virtio_dev_pktmbuf_alloc(struct virtio_net *dev, struct rte_mempool *mp, { struct rte_mbuf *pkt = rte_pktmbuf_alloc(mp); - if (unlikely(pkt == NULL)) + if (unlikely(pkt == NULL)) { + static int rate_lim = 0; + + if (rate_lim++ % 1000 == 0) + RTE_LOG... + return NULL; + } if (rte_pktmbuf_tailroom(pkt) >= data_len) return pkt; Or track this at mempool level and keep stats of failed requests and report that in OvS. That would cover other points too. fbl
