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-rw-r--r--drivers/virtio/virtio_balloon.c109
-rw-r--r--drivers/virtio/virtio_pci.c2
-rw-r--r--drivers/virtio/virtio_ring.c34
3 files changed, 129 insertions, 16 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,
diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c
index 28d9cf7cf72..1d5191fab62 100644
--- a/drivers/virtio/virtio_pci.c
+++ b/drivers/virtio/virtio_pci.c
@@ -702,7 +702,7 @@ static struct pci_driver virtio_pci_driver = {
.name = "virtio-pci",
.id_table = virtio_pci_id_table,
.probe = virtio_pci_probe,
- .remove = virtio_pci_remove,
+ .remove = __devexit_p(virtio_pci_remove),
#ifdef CONFIG_PM
.suspend = virtio_pci_suspend,
.resume = virtio_pci_resume,
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 71929ee00d6..0db906b3c95 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -21,6 +21,24 @@
#include <linux/virtio_config.h>
#include <linux/device.h>
+/* virtio guest is communicating with a virtual "device" that actually runs on
+ * a host processor. Memory barriers are used to control SMP effects. */
+#ifdef CONFIG_SMP
+/* Where possible, use SMP barriers which are more lightweight than mandatory
+ * barriers, because mandatory barriers control MMIO effects on accesses
+ * through relaxed memory I/O windows (which virtio does not use). */
+#define virtio_mb() smp_mb()
+#define virtio_rmb() smp_rmb()
+#define virtio_wmb() smp_wmb()
+#else
+/* We must force memory ordering even if guest is UP since host could be
+ * running on another CPU, but SMP barriers are defined to barrier() in that
+ * configuration. So fall back to mandatory barriers instead. */
+#define virtio_mb() mb()
+#define virtio_rmb() rmb()
+#define virtio_wmb() wmb()
+#endif
+
#ifdef DEBUG
/* For development, we want to crash whenever the ring is screwed. */
#define BAD_RING(_vq, fmt, args...) \
@@ -36,10 +54,9 @@
panic("%s:in_use = %i\n", \
(_vq)->vq.name, (_vq)->in_use); \
(_vq)->in_use = __LINE__; \
- mb(); \
} while (0)
#define END_USE(_vq) \
- do { BUG_ON(!(_vq)->in_use); (_vq)->in_use = 0; mb(); } while(0)
+ do { BUG_ON(!(_vq)->in_use); (_vq)->in_use = 0; } while(0)
#else
#define BAD_RING(_vq, fmt, args...) \
do { \
@@ -221,13 +238,13 @@ static void vring_kick(struct virtqueue *_vq)
START_USE(vq);
/* Descriptors and available array need to be set before we expose the
* new available array entries. */
- wmb();
+ virtio_wmb();
vq->vring.avail->idx += vq->num_added;
vq->num_added = 0;
/* Need to update avail index before checking if we should notify */
- mb();
+ virtio_mb();
if (!(vq->vring.used->flags & VRING_USED_F_NO_NOTIFY))
/* Prod other side to tell it about changes. */
@@ -286,7 +303,7 @@ static void *vring_get_buf(struct virtqueue *_vq, unsigned int *len)
}
/* Only get used array entries after they have been exposed by host. */
- rmb();
+ virtio_rmb();
i = vq->vring.used->ring[vq->last_used_idx%vq->vring.num].id;
*len = vq->vring.used->ring[vq->last_used_idx%vq->vring.num].len;
@@ -324,7 +341,7 @@ static bool vring_enable_cb(struct virtqueue *_vq)
/* We optimistically turn back on interrupts, then check if there was
* more to do. */
vq->vring.avail->flags &= ~VRING_AVAIL_F_NO_INTERRUPT;
- mb();
+ virtio_mb();
if (unlikely(more_used(vq))) {
END_USE(vq);
return false;
@@ -431,8 +448,11 @@ struct virtqueue *vring_new_virtqueue(unsigned int num,
/* Put everything in free lists. */
vq->num_free = num;
vq->free_head = 0;
- for (i = 0; i < num-1; i++)
+ for (i = 0; i < num-1; i++) {
vq->vring.desc[i].next = i+1;
+ vq->data[i] = NULL;
+ }
+ vq->data[i] = NULL;
return &vq->vq;
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-28 22:42:05 +0000