> -----Original Message-----
> From: Chen, Junjie J
> Sent: Tuesday, January 16, 2018 3:39 PM
> To: Yang, Zhiyong <zhiyong.y...@intel.com>; y...@fridaylinux.org;
> maxime.coque...@redhat.com
> Cc: dev@dpdk.org
> Subject: RE: [dpdk-dev] [PATCH] vhost: do deep copy while reallocate vq
>
> Hi
> > > > > @@ -227,6 +227,7 @@ vhost_user_set_vring_num(struct virtio_net
> > *dev,
> > > > > "zero copy is force disabled\n");
> > > > > dev->dequeue_zero_copy = 0;
> > > > > }
> > > > > + TAILQ_INIT(&vq->zmbuf_list);
> > > > > }
> > > > >
> > > > > vq->shadow_used_ring = rte_malloc(NULL, @@ -261,6
> +262,9
> > @@
> > > > > numa_realloc(struct virtio_net *dev, int index)
> > > > > int oldnode, newnode;
> > > > > struct virtio_net *old_dev;
> > > > > struct vhost_virtqueue *old_vq, *vq;
> > > > > + struct zcopy_mbuf *new_zmbuf;
> > > > > + struct vring_used_elem *new_shadow_used_ring;
> > > > > + struct batch_copy_elem *new_batch_copy_elems;
> > > > > int ret;
> > > > >
> > > > > old_dev = dev;
> > > > > @@ -285,6 +289,33 @@ numa_realloc(struct virtio_net *dev, int
> > index)
> > > > > return dev;
> > > > >
> > > > > memcpy(vq, old_vq, sizeof(*vq));
> > > > > + TAILQ_INIT(&vq->zmbuf_list);
> > > > > +
> > > > > + new_zmbuf = rte_malloc_socket(NULL, vq-
> >zmbuf_size *
> > > > > + sizeof(struct zcopy_mbuf), 0, newnode);
> > > > > + if (new_zmbuf) {
> > > > > + rte_free(vq->zmbufs);
> > > > > + vq->zmbufs = new_zmbuf;
> > > > > + }
> > > >
> > > > You need to consider how to handle the case ( rte_malloc_socket
> > > > return NULL).
> > >
> > > If it failed to allocate new_zmbuf, it uses old zmbufs, so as to
> > > keep vhost alive.
> >
> > It sounds reasonable, another question is, for the 3 blocks of memory
> > being allocated, If some succeed , others fails, Does it mean that
> > the code will run on different socket? What's the perf impact if it
> > happens.
>
> The original code doesn't do deep copy and thus access memory on different
> socket, this patch is to mitigate this situation. It does access remote memory
> when one of above allocation failed.
>
> I saw some performance improvement (24.8Gbits/s -> 26.1Gbit/s) on my dev
> machine when only reallocate for zmbufs, while I didn't see significant
> performance difference when allocating vring_used_elem and
> batch_copy_elem.
Great,
Reviewed-by: Zhiyong Yang <zhiyong.y...@intel.com>
Thanks
Zhiyong
