diff options
Diffstat (limited to 'drivers/virtio/virtio_balloon.c')
| -rw-r--r-- | drivers/virtio/virtio_balloon.c | 109 |
1 files changed, 101 insertions, 8 deletions
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index 505be88c82a..369f2eebbad 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -28,7 +28,7 @@ struct virtio_balloon { struct virtio_device *vdev; - struct virtqueue *inflate_vq, *deflate_vq; + struct virtqueue *inflate_vq, *deflate_vq, *stats_vq; /* Where the ballooning thread waits for config to change. */ wait_queue_head_t config_change; @@ -49,6 +49,10 @@ struct virtio_balloon /* The array of pfns we tell the Host about. */ unsigned int num_pfns; u32 pfns[256]; + + /* Memory statistics */ + int need_stats_update; + struct virtio_balloon_stat stats[VIRTIO_BALLOON_S_NR]; }; static struct virtio_device_id id_table[] = { @@ -154,6 +158,72 @@ static void leak_balloon(struct virtio_balloon *vb, size_t num) } } +static inline void update_stat(struct virtio_balloon *vb, int idx, + u16 tag, u64 val) +{ + BUG_ON(idx >= VIRTIO_BALLOON_S_NR); + vb->stats[idx].tag = tag; + vb->stats[idx].val = val; +} + +#define pages_to_bytes(x) ((u64)(x) << PAGE_SHIFT) + +static void update_balloon_stats(struct virtio_balloon *vb) +{ + unsigned long events[NR_VM_EVENT_ITEMS]; + struct sysinfo i; + int idx = 0; + + all_vm_events(events); + si_meminfo(&i); + + update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_IN, + pages_to_bytes(events[PSWPIN])); + update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_OUT, + pages_to_bytes(events[PSWPOUT])); + update_stat(vb, idx++, VIRTIO_BALLOON_S_MAJFLT, events[PGMAJFAULT]); + update_stat(vb, idx++, VIRTIO_BALLOON_S_MINFLT, events[PGFAULT]); + update_stat(vb, idx++, VIRTIO_BALLOON_S_MEMFREE, + pages_to_bytes(i.freeram)); + update_stat(vb, idx++, VIRTIO_BALLOON_S_MEMTOT, + pages_to_bytes(i.totalram)); +} + +/* + * While most virtqueues communicate guest-initiated requests to the hypervisor, + * the stats queue operates in reverse. The driver initializes the virtqueue + * with a single buffer. From that point forward, all conversations consist of + * a hypervisor request (a call to this function) which directs us to refill + * the virtqueue with a fresh stats buffer. Since stats collection can sleep, + * we notify our kthread which does the actual work via stats_handle_request(). + */ +static void stats_request(struct virtqueue *vq) +{ + struct virtio_balloon *vb; + unsigned int len; + + vb = vq->vq_ops->get_buf(vq, &len); + if (!vb) + return; + vb->need_stats_update = 1; + wake_up(&vb->config_change); +} + +static void stats_handle_request(struct virtio_balloon *vb) +{ + struct virtqueue *vq; + struct scatterlist sg; + + vb->need_stats_update = 0; + update_balloon_stats(vb); + + vq = vb->stats_vq; + sg_init_one(&sg, vb->stats, sizeof(vb->stats)); + if (vq->vq_ops->add_buf(vq, &sg, 1, 0, vb) < 0) + BUG(); + vq->vq_ops->kick(vq); +} + static void virtballoon_changed(struct virtio_device *vdev) { struct virtio_balloon *vb = vdev->priv; @@ -190,8 +260,11 @@ static int balloon(void *_vballoon) try_to_freeze(); wait_event_interruptible(vb->config_change, (diff = towards_target(vb)) != 0 + || vb->need_stats_update || kthread_should_stop() || freezing(current)); + if (vb->need_stats_update) + stats_handle_request(vb); if (diff > 0) fill_balloon(vb, diff); else if (diff < 0) @@ -204,10 +277,10 @@ static int balloon(void *_vballoon) static int virtballoon_probe(struct virtio_device *vdev) { struct virtio_balloon *vb; - struct virtqueue *vqs[2]; - vq_callback_t *callbacks[] = { balloon_ack, balloon_ack }; - const char *names[] = { "inflate", "deflate" }; - int err; + struct virtqueue *vqs[3]; + vq_callback_t *callbacks[] = { balloon_ack, balloon_ack, stats_request }; + const char *names[] = { "inflate", "deflate", "stats" }; + int err, nvqs; vdev->priv = vb = kmalloc(sizeof(*vb), GFP_KERNEL); if (!vb) { @@ -219,14 +292,31 @@ static int virtballoon_probe(struct virtio_device *vdev) vb->num_pages = 0; init_waitqueue_head(&vb->config_change); vb->vdev = vdev; + vb->need_stats_update = 0; - /* We expect two virtqueues. */ - err = vdev->config->find_vqs(vdev, 2, vqs, callbacks, names); + /* We expect two virtqueues: inflate and deflate, + * and optionally stat. */ + nvqs = virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ) ? 3 : 2; + err = vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names); if (err) goto out_free_vb; vb->inflate_vq = vqs[0]; vb->deflate_vq = vqs[1]; + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) { + struct scatterlist sg; + vb->stats_vq = vqs[2]; + + /* + * Prime this virtqueue with one buffer so the hypervisor can + * use it to signal us later. + */ + sg_init_one(&sg, vb->stats, sizeof vb->stats); + if (vb->stats_vq->vq_ops->add_buf(vb->stats_vq, + &sg, 1, 0, vb) < 0) + BUG(); + vb->stats_vq->vq_ops->kick(vb->stats_vq); + } vb->thread = kthread_run(balloon, vb, "vballoon"); if (IS_ERR(vb->thread)) { @@ -264,7 +354,10 @@ static void __devexit virtballoon_remove(struct virtio_device *vdev) kfree(vb); } -static unsigned int features[] = { VIRTIO_BALLOON_F_MUST_TELL_HOST }; +static unsigned int features[] = { + VIRTIO_BALLOON_F_MUST_TELL_HOST, + VIRTIO_BALLOON_F_STATS_VQ, +}; static struct virtio_driver virtio_balloon_driver = { .feature_table = features, |