From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751342AbaJOHoF (ORCPT ); Wed, 15 Oct 2014 03:44:05 -0400 Received: from mx1.redhat.com ([209.132.183.28]:7740 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751238AbaJOHoB (ORCPT ); Wed, 15 Oct 2014 03:44:01 -0400 From: Jason Wang To: rusty@rustcorp.com.au, mst@redhat.com, virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org Cc: davem@davemloft.net, eric.dumazet@gmail.com, Jason Wang Subject: [RFC PATCH net-next 2/6] virtio: introduce virtio_enable_cb_avail() Date: Wed, 15 Oct 2014 15:25:26 +0800 Message-Id: <1413357930-45302-3-git-send-email-jasowang@redhat.com> In-Reply-To: <1413357930-45302-1-git-send-email-jasowang@redhat.com> References: <1413357930-45302-1-git-send-email-jasowang@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch introduces virtio_enable_cb_avail() to publish avail idx and used event. This could be used by batched buffer submitting to reduce the number of tx interrupts. Cc: Rusty Russell Cc: Michael S. Tsirkin Signed-off-by: Jason Wang --- drivers/virtio/virtio_ring.c | 22 ++++++++++++++++++++-- include/linux/virtio.h | 2 ++ 2 files changed, 22 insertions(+), 2 deletions(-) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 1b3929f..d67fbf8 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -567,14 +567,32 @@ unsigned virtqueue_enable_cb_prepare(struct virtqueue *_vq) * entry. Always do both to keep code simple. */ vq->vring.avail->flags &= ~VRING_AVAIL_F_NO_INTERRUPT; /* Make sure used event never go backwards */ - if (!vring_need_event(vring_used_event(&vq->vring), - vq->vring.avail->idx, last_used_idx)) + if (vq->vring.avail->idx != vring_used_event(&vq->vring) && + !vring_need_event(vring_used_event(&vq->vring), + vq->vring.avail->idx, last_used_idx)) { vring_used_event(&vq->vring) = last_used_idx; + } END_USE(vq); return last_used_idx; } EXPORT_SYMBOL_GPL(virtqueue_enable_cb_prepare); +bool virtqueue_enable_cb_avail(struct virtqueue *_vq) +{ + struct vring_virtqueue *vq = to_vvq(_vq); + bool ret; + + START_USE(vq); + vq->vring.avail->flags &= ~VRING_AVAIL_F_NO_INTERRUPT; + vring_used_event(&vq->vring) = vq->vring.avail->idx; + ret = vring_need_event(vq->vring.avail->idx, + vq->last_used_idx, vq->vring.used->idx); + END_USE(vq); + + return ret; +} +EXPORT_SYMBOL_GPL(virtqueue_enable_cb_avail); + /** * virtqueue_poll - query pending used buffers * @vq: the struct virtqueue we're talking about. diff --git a/include/linux/virtio.h b/include/linux/virtio.h index b46671e..bfaf058 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -65,6 +65,8 @@ bool virtqueue_enable_cb(struct virtqueue *vq); unsigned virtqueue_enable_cb_prepare(struct virtqueue *vq); +bool virtqueue_enable_cb_avail(struct virtqueue *vq); + bool virtqueue_poll(struct virtqueue *vq, unsigned); bool virtqueue_enable_cb_delayed(struct virtqueue *vq); -- 1.7.1