From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dpdk.org (dpdk.org [92.243.14.124]) by inbox.dpdk.org (Postfix) with ESMTP id 117D9A09EF; Mon, 21 Dec 2020 16:53:07 +0100 (CET) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 5C31ECC6B; Mon, 21 Dec 2020 16:51:25 +0100 (CET) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by dpdk.org (Postfix) with ESMTP id 2F8B7CC6B for ; Mon, 21 Dec 2020 16:51:23 +0100 (CET) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B7ED81FB; Mon, 21 Dec 2020 07:51:22 -0800 (PST) Received: from net-arm-thunderx2-03.shanghai.arm.com (net-arm-thunderx2-03.shanghai.arm.com [10.169.208.206]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 8A3D13F6CF; Mon, 21 Dec 2020 07:51:20 -0800 (PST) From: Joyce Kong To: maxime.coquelin@redhat.com, chenbo.xia@intel.com, honnappa.nagarahalli@arm.com, ruifeng.wang@arm.com Cc: dev@dpdk.org, nd@arm.com Date: Mon, 21 Dec 2020 23:50:31 +0800 Message-Id: <20201221155033.6771-7-joyce.kong@arm.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201221155033.6771-1-joyce.kong@arm.com> References: <20201221155033.6771-1-joyce.kong@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: [dpdk-dev] [PATCH v1 6/8] vhost: relax full barriers for used idx X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" Used idx can be synchronized by one-way barrier instead of full write barrier for split vring. Signed-off-by: Joyce Kong Reviewed-by: Ruifeng Wang --- lib/librte_vhost/vdpa.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/lib/librte_vhost/vdpa.c b/lib/librte_vhost/vdpa.c index ae6fdd24e..99a926a77 100644 --- a/lib/librte_vhost/vdpa.c +++ b/lib/librte_vhost/vdpa.c @@ -217,8 +217,8 @@ rte_vdpa_relay_vring_used(int vid, uint16_t qid, void *vring_m) idx++; } - rte_smp_wmb(); - vq->used->idx = idx_m; + /* used idx is the synchronization point for the split vring */ + __atomic_store_n(&vq->used->idx, idx_m, __ATOMIC_RELEASE); if (dev->features & (1ULL << VIRTIO_RING_F_EVENT_IDX)) vring_used_event(s_vring) = idx_m; -- 2.29.2