> Subject: [dpdk-dev] [memnic PATCH] pmd: use memory barrier function instead > of asm volatile > > Use the DPDK specific function rte_mb() instead of > the GCC statement asm volatile ("" ::: "memory").
Yes, that's preferred for DPDK, I think. Looks okay to me. By the way, I was also asked to use rte atomic function instead of cmpxchg asm statement. My re-submitted version in dpdk-ovs has such a change. What do you think? thanks, Hiroshi > > Signed-off-by: Olivier Matz <olivier.matz at 6wind.com> > --- > common/memnic.h | 2 -- > pmd/pmd_memnic.c | 6 +++--- > 2 files changed, 3 insertions(+), 5 deletions(-) > > diff --git a/common/memnic.h b/common/memnic.h > index 6ff38a0..fdc9fa3 100644 > --- a/common/memnic.h > +++ b/common/memnic.h > @@ -123,8 +123,6 @@ struct memnic_area { > /* for userspace */ > #define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x)) > > -#define barrier() do { asm volatile("": : :"memory"); } while (0) > - > static inline uint32_t cmpxchg(uint32_t *dst, uint32_t old, uint32_t new) > { > volatile uint32_t *ptr = (volatile uint32_t *)dst; > diff --git a/pmd/pmd_memnic.c b/pmd/pmd_memnic.c > index bc01746..1586222 100644 > --- a/pmd/pmd_memnic.c > +++ b/pmd/pmd_memnic.c > @@ -100,7 +100,7 @@ static int memnic_dev_start(struct rte_eth_dev *dev) > > /* invalidate */ > adapter->nic->hdr.valid = 0; > - barrier(); > + rte_mb(); > /* reset */ > adapter->nic->hdr.reset = 1; > /* no need to wait here */ > @@ -242,7 +242,7 @@ static uint16_t memnic_recv_pkts(void *rx_queue, > mb->pkt.data_len = p->len; > rx_pkts[nr] = mb; > > - barrier(); > + rte_mb(); > p->status = MEMNIC_PKT_ST_FREE; > > if (++idx >= MEMNIC_NR_PACKET) > @@ -290,7 +290,7 @@ retry: > > rte_memcpy(p->data, rte_pktmbuf_mtod(tx_pkts[nr], void *), len); > > - barrier(); > + rte_mb(); > p->status = MEMNIC_PKT_ST_FILLED; > > rte_pktmbuf_free(tx_pkts[nr]); > -- > 1.8.4.rc3