From: Konstantin Neumoin <kneumoin@xxxxxxxxxxxxx>
At this moment oom notification in balloon does not work as expected.
After virtballoon_oom_notify there is an infinitive loop:
- virtballoon_oom_notify was called and balloon was deflated
- balloon get notification that config was changed, compare target and
actual and try to reach target again.
This patch adds global variable fail_counter which indicates that oom has
been happened. We check that fail_counter was changed between calls
update_balloon_size_func. In this case we should not try to inflate balloon
even if actual != target.
Signed-off-by: Konstantin Neumoin <kneumoin@xxxxxxxxxxxxx>
Signed-off-by: Denis V. Lunev <den@xxxxxxxxxx>
CC: Michael S. Tsirkin <mst@xxxxxxxxxx>
---
drivers/virtio/virtio_balloon.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 4e7003d..253bf05 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -50,6 +50,8 @@ MODULE_PARM_DESC(oom_pages, "pages to free on OOM");
static struct vfsmount *balloon_mnt;
#endif
+static unsigned long fail_count;
+
struct virtio_balloon {
struct virtio_device *vdev;
struct virtqueue *inflate_vq, *deflate_vq, *stats_vq;
@@ -361,6 +363,8 @@ static int virtballoon_oom_notify(struct notifier_block *self,
unsigned long *freed;
unsigned num_freed_pages;
+ fail_count++;
+
vb = container_of(self, struct virtio_balloon, nb);
if (!virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_DEFLATE_ON_OOM))
return NOTIFY_OK;
@@ -386,11 +390,22 @@ static void update_balloon_size_func(struct work_struct *work)
{
struct virtio_balloon *vb;
s64 diff;
+ static unsigned long fc;
+
+ if (fc == 0)
+ fc = fail_count;
vb = container_of(work, struct virtio_balloon,
update_balloon_size_work);
diff = towards_target(vb);
+ if (fc != fail_count) {
+ fc = fail_count;
+ /* Don't inflate balloon after oom notification */
+ if (diff > 0)
+ return;
+ }
+
if (diff > 0)
diff -= fill_balloon(vb, diff);
else if (diff < 0)
--
2.7.4
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