Hi Hanon,
> -----Original Message----- > From: dev [mailto:dev-boun...@dpdk.org] On Behalf Of Hanoh Haim > Sent: Wednesday, November 15, 2017 8:36 AM > To: dev@dpdk.org > Cc: Hanoh Haim <hh...@cisco.com> > Subject: [dpdk-dev] [PATCH] mbuf: cleanup rte_pktmbuf_lastseg(), fix atomic > usage > > Signed-off-by: Hanoh Haim <hh...@cisco.com> > --- > lib/librte_mbuf/rte_mbuf.h | 27 +++++++++++++-------------- > 1 file changed, 13 insertions(+), 14 deletions(-) > > diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h > index 7e326bb..ab110f8 100644 > --- a/lib/librte_mbuf/rte_mbuf.h > +++ b/lib/librte_mbuf/rte_mbuf.h > @@ -1159,6 +1159,15 @@ static inline void rte_pktmbuf_reset(struct rte_mbuf > *m) > __rte_mbuf_sanity_check(m, 1); > } > > + > +static __rte_always_inline void rte_pktmbuf_reset_before_free(struct > rte_mbuf *m) > +{ > + if (m->next != NULL) { > + m->next = NULL; > + m->nb_segs = 1; > + } > +} > + > /** > * Allocate a new mbuf from a mempool. > * > @@ -1323,8 +1332,7 @@ static inline void rte_pktmbuf_detach(struct rte_mbuf > *m) > m->ol_flags = 0; > > if (rte_mbuf_refcnt_update(md, -1) == 0) { > - md->next = NULL; > - md->nb_segs = 1; > + rte_pktmbuf_reset_before_free(md); > rte_mbuf_refcnt_set(md, 1); > rte_mbuf_raw_free(md); > } > @@ -1354,25 +1362,16 @@ rte_pktmbuf_prefree_seg(struct rte_mbuf *m) > if (RTE_MBUF_INDIRECT(m)) > rte_pktmbuf_detach(m); > > - if (m->next != NULL) { > - m->next = NULL; > - m->nb_segs = 1; > - } > - > + rte_pktmbuf_reset_before_free(m); > return m; > > - } else if (rte_atomic16_add_return(&m->refcnt_atomic, -1) == 0) { > - > + } else if (rte_mbuf_refcnt_update(m, -1) == 0) { That would cause extra read; cmp (and possible slowdown) for atomic refcnt. If that really need to be fixed - probably we need to introduce a new function that would do update without trying to read refctn first - rte_mbuf_refcnt_update_blind() or so. Konstantin > > if (RTE_MBUF_INDIRECT(m)) > rte_pktmbuf_detach(m); > > - if (m->next != NULL) { > - m->next = NULL; > - m->nb_segs = 1; > - } > + rte_pktmbuf_reset_before_free(m); > rte_mbuf_refcnt_set(m, 1); > - > return m; > } > return NULL; > -- > 2.9.3
