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authorJason Wang <jasowang@redhat.com>2019-05-17 07:29:49 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-08-04 10:30:55 +0300
commitad5fc8953d61b99f445db447ac1eadc99a00d47e (patch)
tree5f9a17f90f135966ecd20aadc03efcbada076081
parent56966212e23f82ced10831f7cca02f7339147428 (diff)
downloadlinux-ad5fc8953d61b99f445db447ac1eadc99a00d47e.tar.xz
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 <jasowang@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> [jwang: backport to 4.19, fix conflict in net.c] Signed-off-by: Jack Wang <jinpu.wang@cloud.ionos.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/vhost/net.c22
-rw-r--r--drivers/vhost/scsi.c9
-rw-r--r--drivers/vhost/vhost.c20
-rw-r--r--drivers/vhost/vhost.h5
-rw-r--r--drivers/vhost/vsock.c12
5 files changed, 48 insertions, 20 deletions
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index ae704658b528..ee039444d3c5 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 0cfa925be4ec..087ce17b0c39 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 c163bc15976a..0752f8dc47b1 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 9490e7ddb340..27a78a9b8cc7 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 e440f87ae1d6..58c5c82bc0be 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);