From: "Xie, Huawei" <huawei.xie@intel.com> To: Linhaifeng <haifeng.lin@huawei.com>, "dev@dpdk.org" <dev@dpdk.org> Subject: Re: [dpdk-dev] [PATCH] cast used->idx to volatile Date: Mon, 23 Mar 2015 12:54:35 +0000 Message-ID: <C37D651A908B024F974696C65296B57B0F3F14D3@SHSMSX101.ccr.corp.intel.com> (raw) In-Reply-To: <551005DD.4060508@huawei.com> > -----Original Message----- > From: Linhaifeng [mailto:haifeng.lin@huawei.com] > Sent: Monday, March 23, 2015 8:24 PM > To: dev@dpdk.org > Cc: Ouyang, Changchun; Xie, Huawei > Subject: Re: [dpdk-dev] [PATCH] cast used->idx to volatile > > > > On 2015/3/21 16:07, linhaifeng wrote: > > From: Linhaifeng <haifeng.lin@huawei.com> > > > > Same as rte_vhost_enqueue_burst we should cast used->idx > > to volatile before notify guest. > > > > Signed-off-by: Linhaifeng <haifeng.lin@huawei.com> > > --- > > lib/librte_vhost/vhost_rxtx.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/lib/librte_vhost/vhost_rxtx.c b/lib/librte_vhost/vhost_rxtx.c > > index 535c7a1..8d674d1 100644 > > --- a/lib/librte_vhost/vhost_rxtx.c > > +++ b/lib/librte_vhost/vhost_rxtx.c > > @@ -722,7 +722,7 @@ rte_vhost_dequeue_burst(struct virtio_net *dev, > uint16_t queue_id, > > } > > > > rte_compiler_barrier(); > > - vq->used->idx += entry_success; > > + *(volatile uint16_t *)&vq->used->idx += entry_success; Haifeng: We have compiler barrier before and an external function call behind, so we don't need volatile here. Do you meet issue? > > /* Kick guest if required. */ > > if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT)) > > eventfd_write((int)vq->callfd, 1); > > > > -- > Regards, > Haifeng
next prev parent reply other threads:[~2015-03-23 12:54 UTC|newest] Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-03-21 8:07 linhaifeng 2015-03-23 2:29 ` Linhaifeng 2015-03-23 12:23 ` Linhaifeng 2015-03-23 12:54 ` Xie, Huawei [this message] 2015-03-24 0:59 ` Linhaifeng 2015-03-24 1:53 ` Xie, Huawei 2015-03-24 7:43 ` Linhaifeng 2015-03-24 10:06 ` Xie, Huawei 2015-03-24 12:28 ` Linhaifeng 2015-03-30 9:20 ` Linhaifeng 2015-03-30 15:56 ` Xie, Huawei 2015-04-01 7:50 ` Thomas Monjalon 2015-04-01 14:40 ` Xie, Huawei
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