From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47931) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dVHLg-0005tk-PD for qemu-devel@nongnu.org; Wed, 12 Jul 2017 09:06:41 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dVHLb-0006co-RN for qemu-devel@nongnu.org; Wed, 12 Jul 2017 09:06:36 -0400 Received: from mx1.redhat.com ([209.132.183.28]:51406) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dVHLb-0006cI-KW for qemu-devel@nongnu.org; Wed, 12 Jul 2017 09:06:31 -0400 Date: Wed, 12 Jul 2017 16:06:18 +0300 From: "Michael S. Tsirkin" Message-ID: <20170712160129-mutt-send-email-mst@kernel.org> References: <1499863221-16206-1-git-send-email-wei.w.wang@intel.com> <1499863221-16206-6-git-send-email-wei.w.wang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1499863221-16206-6-git-send-email-wei.w.wang@intel.com> Subject: Re: [Qemu-devel] [PATCH v12 5/8] virtio-balloon: VIRTIO_BALLOON_F_SG List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Wei Wang Cc: linux-kernel@vger.kernel.org, qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, linux-mm@kvack.org, david@redhat.com, cornelia.huck@de.ibm.com, akpm@linux-foundation.org, mgorman@techsingularity.net, aarcange@redhat.com, amit.shah@redhat.com, pbonzini@redhat.com, liliang.opensource@gmail.com, virtio-dev@lists.oasis-open.org, yang.zhang.wz@gmail.com, quan.xu@aliyun.com On Wed, Jul 12, 2017 at 08:40:18PM +0800, Wei Wang wrote: > diff --git a/include/linux/virtio.h b/include/linux/virtio.h > index 28b0e96..9f27101 100644 > --- a/include/linux/virtio.h > +++ b/include/linux/virtio.h > @@ -57,8 +57,28 @@ int virtqueue_add_sgs(struct virtqueue *vq, > void *data, > gfp_t gfp); > > +/* A desc with this init id is treated as an invalid desc */ > +#define VIRTQUEUE_DESC_ID_INIT UINT_MAX > +int virtqueue_add_chain_desc(struct virtqueue *_vq, > + uint64_t addr, > + uint32_t len, > + unsigned int *head_id, > + unsigned int *prev_id, > + bool in); > + > +int virtqueue_add_chain(struct virtqueue *_vq, > + unsigned int head, > + bool indirect, > + struct vring_desc *indirect_desc, > + void *data, > + void *ctx); > + > bool virtqueue_kick(struct virtqueue *vq); > > +bool virtqueue_kick_sync(struct virtqueue *vq); > + > +bool virtqueue_kick_async(struct virtqueue *vq, wait_queue_head_t wq); > + > bool virtqueue_kick_prepare(struct virtqueue *vq); > > bool virtqueue_notify(struct virtqueue *vq); I don't much care for this API. It does exactly what balloon needs, but at cost of e.g. transparently busy-waiting. Unlikely to be a good fit for anything else. If you don't like my original _first/_next/_last, you will need to come up with something else. -- MST