From: Stephen Hemminger <stephen@networkplumber.org>
To: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH 2/2] virtio: clean up space checks on xmit
Date: Sat, 5 Dec 2015 11:50:07 -0800 [thread overview]
Message-ID: <20151205115007.2230a16a@xeon-e3> (raw)
In-Reply-To: <20151204032858.GB29571@yliu-dev.sh.intel.com>
int error;
> >
> > @@ -846,58 +845,49 @@ virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
> > if (likely(nb_used > txvq->vq_nentries - txvq->vq_free_thresh))
> > virtio_xmit_cleanup(txvq, nb_used);
> >
> > - nb_tx = 0;
> > -
> > - while (nb_tx < nb_pkts) {
> > + for (nb_tx = 0; nb_tx < nb_pkts; nb_tx++) {
> > + struct rte_mbuf *txm = tx_pkts[nb_tx];
> > /* Need one more descriptor for virtio header. */
> > - int need = tx_pkts[nb_tx]->nb_segs - txvq->vq_free_cnt + 1;
> > + int need = txm->nb_segs - txvq->vq_free_cnt + 1;
>
> While reviewing the code, I found the var name `need' is not properly
> taken. Maybe `need_cleanup' is better, and it's better to be defined
> as bool type. What do you think of that?
The variable need indicates how many more buffers are needed to
complete the transmit. In later patches, there is a variable slots
so:
needed = slots - free
So if needed is positive, then more buffers are needed than available
and transmit is blocked. If needed is negative then there is free
space available.
>
> (And yes, it has nothing to do with your patch, I just found it we
> can rename it to a better name to improve the code readability a bit.
> If you agree, would you submit a patch, or should I do it?)
>
> >
> > - /*Positive value indicates it need free vring descriptors */
> > + /* Positive value indicates it need free vring descriptors */
> > if (unlikely(need > 0)) {
> > nb_used = VIRTQUEUE_NUSED(txvq);
> > virtio_rmb();
> > need = RTE_MIN(need, (int)nb_used);
> >
> > virtio_xmit_cleanup(txvq, need);
> > - need = (int)tx_pkts[nb_tx]->nb_segs -
> > - txvq->vq_free_cnt + 1;
> > + need = txm->nb_segs - txvq->vq_free_cnt + 1;
> > + if (unlikely(need > 0)) {
> > + PMD_TX_LOG(ERR,
> > + "No free tx descriptors to transmit");
> > + break;
> > + }
> ^
>
> Minor nit: I found a leading white space there.
Hmm. I didn't see it in checkpatch.
next prev parent reply other threads:[~2015-12-07 18:10 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-04 1:12 [dpdk-dev] [PATCH 0/2] virtio: bugfix and cleanup Stephen Hemminger
2015-12-04 1:12 ` [dpdk-dev] [PATCH 1/2] virtio: make sure rcv mbuf initialized correctly Stephen Hemminger
2015-12-04 3:18 ` Yuanhan Liu
2015-12-04 1:12 ` [dpdk-dev] [PATCH 2/2] virtio: clean up space checks on xmit Stephen Hemminger
2015-12-04 3:28 ` Yuanhan Liu
2015-12-05 19:50 ` Stephen Hemminger [this message]
2015-12-08 1:54 ` Yuanhan Liu
2015-12-06 23:02 ` [dpdk-dev] [PATCH 0/2] virtio: bugfix and cleanup Thomas Monjalon
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