From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Christie Date: Thu, 12 Nov 2020 23:19:10 +0000 Subject: [PATCH 10/10] vhost-scsi: create a woker per IO vq Message-Id: <1605223150-10888-12-git-send-email-michael.christie@oracle.com> List-Id: References: <1605223150-10888-1-git-send-email-michael.christie@oracle.com> In-Reply-To: <1605223150-10888-1-git-send-email-michael.christie@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: stefanha@redhat.com, qemu-devel@nongnu.org, fam@euphon.net, linux-scsi@vger.kernel.org, target-devel@vger.kernel.org, mst@redhat.com, jasowang@redhat.com, pbonzini@redhat.com, virtualization@lists.linux-foundation.org This patch has vhost-scsi create a worker thread per IO vq. It also adds a modparam to enable the feature, because I was thinking existing setups might not be expecting the extra threading use, so the default is to use the old single thread multiple vq behavior. Signed-off-by: Mike Christie --- drivers/vhost/scsi.c | 38 +++++++++++++++++++++++++++++++++++++- 1 file changed, 37 insertions(+), 1 deletion(-) diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index 612359d..3fb147f 100644 --- a/drivers/vhost/scsi.c +++ b/drivers/vhost/scsi.c @@ -62,6 +62,12 @@ */ #define VHOST_SCSI_WEIGHT 256 +static bool vhost_scsi_worker_per_io_vq; +module_param_named(thread_per_io_virtqueue, vhost_scsi_worker_per_io_vq, bool, + 0644); +MODULE_PARM_DESC(thread_per_io_virtqueue, + "Create a worker thread per IO virtqueue. Set to true to turn on. Default is false where all virtqueues share a thread."); + struct vhost_scsi_inflight { /* Wait for the flush operation to finish */ struct completion comp; @@ -1805,6 +1811,36 @@ static int vhost_scsi_set_features(struct vhost_scsi *vs, u64 features) return 0; } +static int vhost_scsi_enable_vring(struct vhost_virtqueue *vq, bool enable) +{ + struct vhost_scsi *vs = container_of(vq->dev, struct vhost_scsi, dev); + /* + * For compat, we have the evt, ctl and first IO vq share worker0 like + * is setup by default. Additional vqs get their own worker. + */ + if (vq = &vs->vqs[VHOST_SCSI_VQ_CTL].vq || + vq = &vs->vqs[VHOST_SCSI_VQ_EVT].vq || + vq = &vs->vqs[VHOST_SCSI_VQ_IO].vq) + return 0; + + if (enable) { + if (!vhost_scsi_worker_per_io_vq) + return 0; + if (vq->worker_id != 0) + return 0; + return vhost_vq_worker_add(vq->dev, vq); + } else { + if (vq->worker_id = 0) + return 0; + vhost_vq_worker_remove(vq->dev, vq); + return 0; + } +} + +static struct vhost_dev_ops vhost_scsi_dev_ops = { + .enable_vring = vhost_scsi_enable_vring, +}; + static int vhost_scsi_open(struct inode *inode, struct file *f) { struct vhost_scsi_virtqueue *svq; @@ -1843,7 +1879,7 @@ static int vhost_scsi_open(struct inode *inode, struct file *f) svq->vq.handle_kick = vhost_scsi_handle_kick; } vhost_dev_init(&vs->dev, vqs, VHOST_SCSI_MAX_VQ, UIO_MAXIOV, - VHOST_SCSI_WEIGHT, 0, true, NULL); + VHOST_SCSI_WEIGHT, 0, true, &vhost_scsi_dev_ops); vhost_scsi_init_inflight(vs, NULL); -- 1.8.3.1