When rte_pktmbuf_prefree_seg() resets an mbuf about to be freed, it doesn't write the fields that already have the required values. This saves a memory store operation when all the fields already have the required values.
This patch adds the same optimization to __rte_pktmbuf_free_direct(), to improve the performance for freeing a direct buffer being detached from a packet mbuf, i.e. saving a memory store operation when all the fields (of the buffer being freed) already have the required values. Signed-off-by: Morten Brørup <[email protected]> --- lib/mbuf/rte_mbuf.h | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/lib/mbuf/rte_mbuf.h b/lib/mbuf/rte_mbuf.h index 2004391f57..592af2388c 100644 --- a/lib/mbuf/rte_mbuf.h +++ b/lib/mbuf/rte_mbuf.h @@ -1334,17 +1334,23 @@ static inline void __rte_pktmbuf_free_direct(struct rte_mbuf *m) { struct rte_mbuf *md; + bool refcnt_not_one; RTE_ASSERT(RTE_MBUF_CLONED(m)); md = rte_mbuf_from_indirect(m); - if (rte_mbuf_refcnt_update(md, -1) == 0) { - md->next = NULL; - md->nb_segs = 1; + refcnt_not_one = unlikely(rte_mbuf_refcnt_read(md) != 1); + if (refcnt_not_one && __rte_mbuf_refcnt_update(md, -1) != 0) + return; + + if (refcnt_not_one) rte_mbuf_refcnt_set(md, 1); - rte_mbuf_raw_free(md); - } + if (md->nb_segs != 1) + md->nb_segs = 1; + if (md->next != NULL) + md->next = NULL; + rte_mbuf_raw_free(md); } /** -- 2.43.0
