From: Luiz capitulino <lcapitulino@xxxxxxxxxx>
This is necessary for automatic ballooning. If the guest gets
under pressure while there's an on-going inflation operation,
we want the guest to do the following:
1. Stop on-going inflation
2. Notify the host we're under pressure
3. Wait for host's acknowledge
While the guest is waiting the host has the opportunity to
reset num_pages to a value before the guest got into pressure.
This will cancel current inflation.
Signed-off-by: Luiz capitulino <lcapitulino@xxxxxxxxxx>
---
drivers/virtio/virtio_balloon.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 1c3ee71..7f5b7d2 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -188,8 +188,13 @@ static void fill_balloon(struct virtio_balloon *vb, size_t num)
mutex_lock(&vb->balloon_lock);
for (vb->num_pfns = 0; vb->num_pfns < num;
vb->num_pfns += VIRTIO_BALLOON_PAGES_PER_PAGE) {
- struct page *page = balloon_page_enqueue(vb_dev_info);
+ struct page *page;
+ if (guest_under_pressure(vb)) {
+ break;
+ }
+
+ page = balloon_page_enqueue(vb_dev_info);
if (!page) {
dev_info_ratelimited(&vb->vdev->dev,
"Out of puff! Can't get %u pages\n",
--
1.8.1.4
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