+ Justin He as Jerin requested.
> -----Original Message-----
> From: Jerin Jacob <jerin.ja...@caviumnetworks.com>
> Sent: Thursday, September 20, 2018 2:41 PM
> To: Gavin Hu (Arm Technology China) <gavin...@arm.com>
> Cc: dev@dpdk.org; Honnappa Nagarahalli
> <honnappa.nagaraha...@arm.com>; Steve Capper
> <steve.cap...@arm.com>; Ola Liljedahl <ola.liljed...@arm.com>; nd
> <n...@arm.com>; sta...@dpdk.org; jia...@hxt-semitech.com
> Subject: Re: [PATCH v4 2/4] ring: read tail using atomic load
>
> -----Original Message-----
> > Date: Mon, 17 Sep 2018 16:11:17 +0800
> > From: Gavin Hu <gavin...@arm.com>
> > To: dev@dpdk.org
> > CC: gavin...@arm.com, honnappa.nagaraha...@arm.com,
> > steve.cap...@arm.com, ola.liljed...@arm.com,
> > jerin.ja...@caviumnetworks.com, n...@arm.com, sta...@dpdk.org
> > Subject: [PATCH v4 2/4] ring: read tail using atomic load
> > X-Mailer: git-send-email 2.7.4
> >
> >
> > In update_tail, read ht->tail using __atomic_load.Although the
> > compiler currently seems to be doing the right thing even without
> > _atomic_load, we don't want to give the compiler freedom to optimise
> > what should be an atomic load, it should not be arbitarily moved
> > around.
> >
> > Fixes: 39368ebfc6 ("ring: introduce C11 memory model barrier option")
> > Cc: sta...@dpdk.org
>
>
> + Jia He <jia...@hxt-semitech.com>
>
> >
> > Signed-off-by: Gavin Hu <gavin...@arm.com>
> > Reviewed-by: Honnappa Nagarahalli <honnappa.nagaraha...@arm.com>
> > Reviewed-by: Steve Capper <steve.cap...@arm.com>
> > Reviewed-by: Ola Liljedahl <ola.liljed...@arm.com>
> > ---
> > lib/librte_ring/rte_ring_c11_mem.h | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/lib/librte_ring/rte_ring_c11_mem.h
> > b/lib/librte_ring/rte_ring_c11_mem.h
> > index 94df3c4..234fea0 100644
> > --- a/lib/librte_ring/rte_ring_c11_mem.h
> > +++ b/lib/librte_ring/rte_ring_c11_mem.h
> > @@ -21,7 +21,8 @@ update_tail(struct rte_ring_headtail *ht, uint32_t
> old_val, uint32_t new_val,
> > * we need to wait for them to complete
> > */
> > if (!single)
> > - while (unlikely(ht->tail != old_val))
> > + while (unlikely(old_val != __atomic_load_n(&ht->tail,
> > + __ATOMIC_RELAXED)))
> > rte_pause();
> >
> > __atomic_store_n(&ht->tail, new_val, __ATOMIC_RELEASE);
> > --
> > 2.7.4
> >
