From: Jason Wang Date: Fri, 17 May 2019 04:29:49 +0000 (-0400) Subject: vhost: introduce vhost_exceeds_weight() X-Git-Tag: v4.19.64~14 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=ad5fc8953d61b99f445db447ac1eadc99a00d47e;p=platform%2Fkernel%2Flinux-rpi.git vhost: introduce vhost_exceeds_weight() commit e82b9b0727ff6d665fff2d326162b460dded554d upstream. We used to have vhost_exceeds_weight() for vhost-net to: - prevent vhost kthread from hogging the cpu - balance the time spent between TX and RX This function could be useful for vsock and scsi as well. So move it to vhost.c. Device must specify a weight which counts the number of requests, or it can also specific a byte_weight which counts the number of bytes that has been processed. Signed-off-by: Jason Wang Reviewed-by: Stefan Hajnoczi Signed-off-by: Michael S. Tsirkin [jwang: backport to 4.19, fix conflict in net.c] Signed-off-by: Jack Wang Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index ae70465..ee03944 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -497,12 +497,6 @@ static size_t init_iov_iter(struct vhost_virtqueue *vq, struct iov_iter *iter, return iov_iter_count(iter); } -static bool vhost_exceeds_weight(int pkts, int total_len) -{ - return total_len >= VHOST_NET_WEIGHT || - pkts >= VHOST_NET_PKT_WEIGHT; -} - static int get_tx_bufs(struct vhost_net *net, struct vhost_net_virtqueue *nvq, struct msghdr *msg, @@ -598,10 +592,8 @@ static void handle_tx_copy(struct vhost_net *net, struct socket *sock) err, len); if (++nvq->done_idx >= VHOST_NET_BATCH) vhost_net_signal_used(nvq); - if (vhost_exceeds_weight(++sent_pkts, total_len)) { - vhost_poll_queue(&vq->poll); + if (vhost_exceeds_weight(vq, ++sent_pkts, total_len)) break; - } } vhost_net_signal_used(nvq); @@ -701,10 +693,9 @@ static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock) else vhost_zerocopy_signal_used(net, vq); vhost_net_tx_packet(net); - if (unlikely(vhost_exceeds_weight(++sent_pkts, total_len))) { - vhost_poll_queue(&vq->poll); + if (unlikely(vhost_exceeds_weight(vq, ++sent_pkts, + total_len))) break; - } } } @@ -1027,10 +1018,8 @@ static void handle_rx(struct vhost_net *net) vhost_log_write(vq, vq_log, log, vhost_len, vq->iov, in); total_len += vhost_len; - if (unlikely(vhost_exceeds_weight(++recv_pkts, total_len))) { - vhost_poll_queue(&vq->poll); + if (unlikely(vhost_exceeds_weight(vq, ++recv_pkts, total_len))) goto out; - } } if (unlikely(busyloop_intr)) vhost_poll_queue(&vq->poll); @@ -1115,7 +1104,8 @@ static int vhost_net_open(struct inode *inode, struct file *f) vhost_net_buf_init(&n->vqs[i].rxq); } vhost_dev_init(dev, vqs, VHOST_NET_VQ_MAX, - UIO_MAXIOV + VHOST_NET_BATCH); + UIO_MAXIOV + VHOST_NET_BATCH, + VHOST_NET_WEIGHT, VHOST_NET_PKT_WEIGHT); vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, EPOLLOUT, dev); vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, EPOLLIN, dev); diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index 0cfa925..087ce17 100644 --- a/drivers/vhost/scsi.c +++ b/drivers/vhost/scsi.c @@ -57,6 +57,12 @@ #define VHOST_SCSI_PREALLOC_UPAGES 2048 #define VHOST_SCSI_PREALLOC_PROT_SGLS 2048 +/* Max number of requests before requeueing the job. + * Using this limit prevents one virtqueue from starving others with + * request. + */ +#define VHOST_SCSI_WEIGHT 256 + struct vhost_scsi_inflight { /* Wait for the flush operation to finish */ struct completion comp; @@ -1398,7 +1404,8 @@ static int vhost_scsi_open(struct inode *inode, struct file *f) vqs[i] = &vs->vqs[i].vq; vs->vqs[i].vq.handle_kick = vhost_scsi_handle_kick; } - vhost_dev_init(&vs->dev, vqs, VHOST_SCSI_MAX_VQ, UIO_MAXIOV); + vhost_dev_init(&vs->dev, vqs, VHOST_SCSI_MAX_VQ, UIO_MAXIOV, + VHOST_SCSI_WEIGHT, 0); vhost_scsi_init_inflight(vs, NULL); diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index c163bc1..0752f8d 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -413,8 +413,24 @@ static void vhost_dev_free_iovecs(struct vhost_dev *dev) vhost_vq_free_iovecs(dev->vqs[i]); } +bool vhost_exceeds_weight(struct vhost_virtqueue *vq, + int pkts, int total_len) +{ + struct vhost_dev *dev = vq->dev; + + if ((dev->byte_weight && total_len >= dev->byte_weight) || + pkts >= dev->weight) { + vhost_poll_queue(&vq->poll); + return true; + } + + return false; +} +EXPORT_SYMBOL_GPL(vhost_exceeds_weight); + void vhost_dev_init(struct vhost_dev *dev, - struct vhost_virtqueue **vqs, int nvqs, int iov_limit) + struct vhost_virtqueue **vqs, int nvqs, + int iov_limit, int weight, int byte_weight) { struct vhost_virtqueue *vq; int i; @@ -428,6 +444,8 @@ void vhost_dev_init(struct vhost_dev *dev, dev->mm = NULL; dev->worker = NULL; dev->iov_limit = iov_limit; + dev->weight = weight; + dev->byte_weight = byte_weight; init_llist_head(&dev->work_list); init_waitqueue_head(&dev->wait); INIT_LIST_HEAD(&dev->read_list); diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h index 9490e7d..27a78a9 100644 --- a/drivers/vhost/vhost.h +++ b/drivers/vhost/vhost.h @@ -171,10 +171,13 @@ struct vhost_dev { struct list_head pending_list; wait_queue_head_t wait; int iov_limit; + int weight; + int byte_weight; }; +bool vhost_exceeds_weight(struct vhost_virtqueue *vq, int pkts, int total_len); void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs, - int nvqs, int iov_limit); + int nvqs, int iov_limit, int weight, int byte_weight); long vhost_dev_set_owner(struct vhost_dev *dev); bool vhost_dev_has_owner(struct vhost_dev *dev); long vhost_dev_check_owner(struct vhost_dev *); diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c index e440f87..58c5c82 100644 --- a/drivers/vhost/vsock.c +++ b/drivers/vhost/vsock.c @@ -21,6 +21,14 @@ #include "vhost.h" #define VHOST_VSOCK_DEFAULT_HOST_CID 2 +/* Max number of bytes transferred before requeueing the job. + * Using this limit prevents one virtqueue from starving others. */ +#define VHOST_VSOCK_WEIGHT 0x80000 +/* Max number of packets transferred before requeueing the job. + * Using this limit prevents one virtqueue from starving others with + * small pkts. + */ +#define VHOST_VSOCK_PKT_WEIGHT 256 enum { VHOST_VSOCK_FEATURES = VHOST_FEATURES, @@ -531,7 +539,9 @@ static int vhost_vsock_dev_open(struct inode *inode, struct file *file) vsock->vqs[VSOCK_VQ_TX].handle_kick = vhost_vsock_handle_tx_kick; vsock->vqs[VSOCK_VQ_RX].handle_kick = vhost_vsock_handle_rx_kick; - vhost_dev_init(&vsock->dev, vqs, ARRAY_SIZE(vsock->vqs), UIO_MAXIOV); + vhost_dev_init(&vsock->dev, vqs, ARRAY_SIZE(vsock->vqs), + UIO_MAXIOV, VHOST_VSOCK_PKT_WEIGHT, + VHOST_VSOCK_WEIGHT); file->private_data = vsock; spin_lock_init(&vsock->send_pkt_list_lock);