---

yaml
---
r: 284242
b: refs/heads/master
c: e93300b
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: ee7cd8981e15bcb365fc762afe3fc47b8242f630
+refs/heads/master: e93300b1afc7cd4fe1e741ceaf06714d060e88b8

trunk/drivers/virtio/virtio_ring.c

@@ -22,6 +22,7 @@
 #include <linux/device.h>
 #include <linux/slab.h>
 #include <linux/module.h>
+#include <linux/hrtimer.h>
 
 /* virtio guest is communicating with a virtual "device" that actually runs on
  * a host processor.  Memory barriers are used to control SMP effects. */
@@ -108,6 +109,10 @@ struct vring_virtqueue
 #ifdef DEBUG
 	/* They're supposed to lock for us. */
 	unsigned int in_use;
+
+	/* Figure out if their kicks are too delayed. */
+	bool last_add_time_valid;
+	ktime_t last_add_time;
 #endif
 
 	/* Tokens for callbacks. */
@@ -198,6 +203,19 @@ int virtqueue_add_buf(struct virtqueue *_vq,
 
 	BUG_ON(data == NULL);
 
+#ifdef DEBUG
+	{
+		ktime_t now = ktime_get();
+
+		/* No kick or get, with .1 second between?  Warn. */
+		if (vq->last_add_time_valid)
+			WARN_ON(ktime_to_ms(ktime_sub(now, vq->last_add_time))
+					    > 100);
+		vq->last_add_time = now;
+		vq->last_add_time_valid = true;
+	}
+#endif
+
 	/* If the host supports indirect descriptor tables, and we have multiple
 	 * buffers, then go indirect. FIXME: tune this threshold */
 	if (vq->indirect && (out + in) > 1 && vq->num_free) {
@@ -298,6 +316,14 @@ bool virtqueue_kick_prepare(struct virtqueue *_vq)
 	new = vq->vring.avail->idx;
 	vq->num_added = 0;
 
+#ifdef DEBUG
+	if (vq->last_add_time_valid) {
+		WARN_ON(ktime_to_ms(ktime_sub(ktime_get(),
+					      vq->last_add_time)) > 100);
+	}
+	vq->last_add_time_valid = false;
+#endif
+
 	if (vq->event) {
 		needs_kick = vring_need_event(vring_avail_event(&vq->vring),
 					      new, old);
@@ -435,6 +461,10 @@ void *virtqueue_get_buf(struct virtqueue *_vq, unsigned int *len)
 		virtio_mb(vq);
 	}
 
+#ifdef DEBUG
+	vq->last_add_time_valid = false;
+#endif
+
 	END_USE(vq);
 	return ret;
 }
@@ -620,6 +650,7 @@ struct virtqueue *vring_new_virtqueue(unsigned int num,
 	list_add_tail(&vq->vq.list, &vdev->vqs);
 #ifdef DEBUG
 	vq->in_use = false;
+	vq->last_add_time_valid = false;
 #endif
 
 	vq->indirect = virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC);