From e82b9b0727ff6d665fff2d326162b460dded554d Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Fri, 17 May 2019 00:29:49 -0400 Subject: vhost: introduce vhost_exceeds_weight() 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 --- drivers/vhost/scsi.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'drivers/vhost/scsi.c') diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c index c090d177bd75..27c9dac9f518 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; @@ -1621,7 +1627,8 @@ 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); -- cgit v1.2.3