[dpdk-dev] [PATCH v6 1/2] kni: add bulk function to free mbufs
Olivier Matz
olivier.matz at 6wind.com
Mon Jan 23 13:59:47 CET 2017
Hi,
On Thu, 19 Jan 2017 11:46:58 +0700, Sergey Vyazmitinov
<s.vyazmitinov at brain4net.com> wrote:
> Suggested-by: Stephen Hemminger <stephen at networkplumber.org>
> Signed-off-by: Sergey Vyazmitinov <s.vyazmitinov at brain4net.com>
> ---
> v3:
> * Fixed issue with possible different mempools in buffer list.
> * Fixed issue with wrong rte_pktmbuf_alloc_bulk function return value
> processing in the kni_allocate_mbufs.
> ---
> lib/librte_mbuf/rte_mbuf.h | 49
> ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 49
> insertions(+)
>
> diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
> index 4476d75..69d314f 100644
> --- a/lib/librte_mbuf/rte_mbuf.h
> +++ b/lib/librte_mbuf/rte_mbuf.h
> @@ -306,6 +306,9 @@ extern "C" {
> /** Alignment constraint of mbuf private area. */
> #define RTE_MBUF_PRIV_ALIGN 8
>
> +/** Maximum number of mbufs freed in bulk. */
> +#define RTE_MBUF_BULK_FREE 64
> +
> /**
> * Get the name of a RX offload flag
> *
> @@ -1261,6 +1264,52 @@ static inline void rte_pktmbuf_free(struct
> rte_mbuf *m) }
>
> /**
> + * Free n packets mbuf back into its original mempool.
> + *
> + * Free each mbuf, and all its segments in case of chained buffers.
> Each
> + * segment is added back into its original mempool.
> + *
> + * @param mp
> + * The packets mempool.
This parameter was removed, it could be removed from the API comment.
> + * @param mbufs
> + * The packets mbufs array to be freed.
> + * @param n
> + * Number of packets.
> + */
> +static inline void rte_pktmbuf_free_bulk(struct rte_mbuf **mbufs,
> + unsigned int n)
I suggest we could use mbuf instead of pktmbuf in the function name.
It's a bit shorter, and the function would also apply on ctrlmbuf.
Also, the struct rte_mbuf **mbufs could probably be replaced by struct
rte_mbuf * const *mbufs.
> +{
> + void *tofree[RTE_MBUF_BULK_FREE];
> + struct rte_mempool *mp = NULL;
> + unsigned int i, count = 0;
> +
> + for (i = 0; i < n; i++) {
> + struct rte_mbuf *m, *m_next;
> +
> + for (m = mbufs[i]; m; m = m_next) {
> + m_next = m->next;
> +
> + if (count > 0 &&
> + (unlikely(m->pool != mp ||
> + count == RTE_MBUF_BULK_FREE))) {
> + rte_mempool_put_bulk(mp, tofree,
> count);
> + count = 0;
> + }
> +
> + mp = m->pool;
> +
> + if (likely(__rte_pktmbuf_prefree_seg(m) !=
> NULL)) {
> + m->next = NULL;
> + tofree[count++] = m;
> + }
> + }
> + }
> +
> + if (likely(count > 0))
> + rte_mempool_put_bulk(mp, tofree, count);
> +}
> +
> +/**
> * Creates a "clone" of the given packet mbuf.
> *
The function looks good to me, thank you. It looks also better than
what I've suggested in [1], since it properly manage mbuf chains. On
the other hand, I think my proposal could also help in drivers, where
segments are already unchained. I'll submit it in a RFC.
[1] http://dpdk.org/ml/archives/dev/2017-January/054538.html
One more thing, maybe it's worth adding a basic test in
app/test/test_mbuf.c.
Thanks,
Olivier
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