> -----Original Message-----
> From: Zoltan Kiss [mailto:zoltan.kiss at linaro.org]
> Sent: Thursday, March 26, 2015 4:46 PM
> To: Ananyev, Konstantin; dev at dpdk.org
> Subject: Re: [dpdk-dev] [PATCH] examples/vhost: use library routines instead
> of local copies
>
>
>
> On 26/03/15 01:20, Ananyev, Konstantin wrote:
> >
> >
> >> -----Original Message-----
> >> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Zoltan Kiss
> >> Sent: Wednesday, March 25, 2015 6:43 PM
> >> To: dev at dpdk.org
> >> Cc: Zoltan Kiss
> >> Subject: [dpdk-dev] [PATCH] examples/vhost: use library routines instead
> >> of local copies
> >>
> >> This macro and function were copies from the mbuf library, no reason to
> >> keep
> >> them.
> >
> > NACK
> > You can't use RTE_MBUF_INDIRECT macro here.
> > If you'll look at vhost code carefully, you'll realise that we don't use
> > standard rte_pktmbuf_attach() here.
> > As we attach mbuf not to another mbuf but to external memory buffer, passed
> > to us by virtio device.
> > Look at attach_rxmbuf_zcp().
> Yes, I think the proper fix is to set the flag in attach_rxmbuf_zcp()
> and virtio_tx_route_zcp(), then you can use the library macro here.
No, it is not.
IND_ATTACHED_MBUF flag indicates that that mbuf attached to another mbuf and
__rte_pktmbuf_prefree_seg()
would try to do mbuf detach.
We definetly don't want to set IND_ATTACHED_MBUF here.
I think there is no need to fix anything here.
Konstantin
>
> > Though I suppose, we can replace pktmbuf_detach_zcp() , with
> > rte_pktmbuf_detach() - they are doing identical things.
> Yes, the only difference is that the latter do "m->ol_flags = 0" as well.
>
> > BTW, I wonder did you ever test your patch?
> Indeed I did not, shame on me. I don't have a KVM setup at hand. This
> fix were born as a side effect of the cleaning up in the library,
> and I'm afraid I don't have the time right now to create a KVM setup.
> Could anyone who has it at hand help out to run a quick test? (for the
> v2 of this patch, which I'll send in shortly)
>
> Regards,
>
> Zoltan
>
> > My guess it would cause vhost with '--zero-copy' to crash or corrupt the
> > packets straightway.
> >
> > Konstantin
> >
> >>
> >> Signed-off-by: Zoltan Kiss <zoltan.kiss at linaro.org>
> >> ---
> >> examples/vhost/main.c | 38 +++++---------------------------------
> >> 1 file changed, 5 insertions(+), 33 deletions(-)
> >>
> >> diff --git a/examples/vhost/main.c b/examples/vhost/main.c
> >> index c3fcb80..1c998a5 100644
> >> --- a/examples/vhost/main.c
> >> +++ b/examples/vhost/main.c
> >> @@ -139,8 +139,6 @@
> >> /* Number of descriptors per cacheline. */
> >> #define DESC_PER_CACHELINE (RTE_CACHE_LINE_SIZE / sizeof(struct
> >> vring_desc))
> >>
> >> -#define MBUF_EXT_MEM(mb) (RTE_MBUF_FROM_BADDR((mb)->buf_addr) != (mb))
> >> -
> >> /* mask of enabled ports */
> >> static uint32_t enabled_port_mask = 0;
> >>
> >> @@ -1538,32 +1536,6 @@ attach_rxmbuf_zcp(struct virtio_net *dev)
> >> return;
> >> }
> >>
> >> -/*
> >> - * Detach an attched packet mbuf -
> >> - * - restore original mbuf address and length values.
> >> - * - reset pktmbuf data and data_len to their default values.
> >> - * All other fields of the given packet mbuf will be left intact.
> >> - *
> >> - * @param m
> >> - * The attached packet mbuf.
> >> - */
> >> -static inline void pktmbuf_detach_zcp(struct rte_mbuf *m)
> >> -{
> >> - const struct rte_mempool *mp = m->pool;
> >> - void *buf = RTE_MBUF_TO_BADDR(m);
> >> - uint32_t buf_ofs;
> >> - uint32_t buf_len = mp->elt_size - sizeof(*m);
> >> - m->buf_physaddr = rte_mempool_virt2phy(mp, m) + sizeof(*m);
> >> -
> >> - m->buf_addr = buf;
> >> - m->buf_len = (uint16_t)buf_len;
> >> -
> >> - buf_ofs = (RTE_PKTMBUF_HEADROOM <= m->buf_len) ?
> >> - RTE_PKTMBUF_HEADROOM : m->buf_len;
> >> - m->data_off = buf_ofs;
> >> -
> >> - m->data_len = 0;
> >> -}
> >>
> >> /*
> >> * This function is called after packets have been transimited. It
> >> fetchs mbuf
> >> @@ -1590,8 +1562,8 @@ txmbuf_clean_zcp(struct virtio_net *dev, struct
> >> vpool *vpool)
> >>
> >> for (index = 0; index < mbuf_count; index++) {
> >> mbuf = __rte_mbuf_raw_alloc(vpool->pool);
> >> - if (likely(MBUF_EXT_MEM(mbuf)))
> >> - pktmbuf_detach_zcp(mbuf);
> >> + if (likely(RTE_MBUF_INDIRECT(mbuf)))
> >> + rte_pktmbuf_detach(mbuf);
> >> rte_ring_sp_enqueue(vpool->ring, mbuf);
> >>
> >> /* Update used index buffer information. */
> >> @@ -1653,8 +1625,8 @@ static void mbuf_destroy_zcp(struct vpool *vpool)
> >> for (index = 0; index < mbuf_count; index++) {
> >> mbuf = __rte_mbuf_raw_alloc(vpool->pool);
> >> if (likely(mbuf != NULL)) {
> >> - if (likely(MBUF_EXT_MEM(mbuf)))
> >> - pktmbuf_detach_zcp(mbuf);
> >> + if (likely(RTE_MBUF_INDIRECT(mbuf)))
> >> + rte_pktmbuf_detach(mbuf);
> >> rte_ring_sp_enqueue(vpool->ring, (void *)mbuf);
> >> }
> >> }
> >> @@ -2149,7 +2121,7 @@ switch_worker_zcp(__attribute__((unused)) void *arg)
> >> }
> >> while (likely(rx_count)) {
> >> rx_count--;
> >> - pktmbuf_detach_zcp(
> >> + rte_pktmbuf_detach(
> >> pkts_burst[rx_count]);
> >> rte_ring_sp_enqueue(
> >> vpool_array[index].ring,
> >> --
> >> 1.9.1
> >
