+ Justin He as Jerin requested.
> -----Original Message----- > From: Jerin Jacob <[email protected]> > Sent: Thursday, September 20, 2018 2:41 PM > To: Gavin Hu (Arm Technology China) <[email protected]> > Cc: [email protected]; Honnappa Nagarahalli > <[email protected]>; Steve Capper > <[email protected]>; Ola Liljedahl <[email protected]>; nd > <[email protected]>; [email protected]; [email protected] > 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 <[email protected]> > > To: [email protected] > > CC: [email protected], [email protected], > > [email protected], [email protected], > > [email protected], [email protected], [email protected] > > 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: [email protected] > > > + Jia He <[email protected]> > > > > > Signed-off-by: Gavin Hu <[email protected]> > > Reviewed-by: Honnappa Nagarahalli <[email protected]> > > Reviewed-by: Steve Capper <[email protected]> > > Reviewed-by: Ola Liljedahl <[email protected]> > > --- > > 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 > >
