virtio_balloon: return the amount of freed memory from leak_balloon()

This value would be useful in the next patch to provide the amount of
the freed memory for OOM killer.

Signed-off-by: Raushaniya Maksudova <rmaksudova@parallels.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Rusty Russell <rusty@rustcorp.com.au>
CC: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

1 files changed, 4 insertions, 1 deletions

diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index c9703d4d6f67..ff71fdcf3345 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -168,8 +168,9 @@ static void release_pages_by_pfn(const u32 pfns[], unsigned int num)
         }
 }
 
-static void leak_balloon(struct virtio_balloon *vb, size_t num)
+static unsigned leak_balloon(struct virtio_balloon *vb, size_t num)
 {
+        unsigned num_freed_pages;
         struct page *page;
         struct balloon_dev_info *vb_dev_info = &vb->vb_dev_info;
 
@@ -186,6 +187,7 @@ static void leak_balloon(struct virtio_balloon *vb, size_t num)
                 vb->num_pages -= VIRTIO_BALLOON_PAGES_PER_PAGE;
         }
 
+        num_freed_pages = vb->num_pfns;
         /*
          * Note that if
          * virtio_has_feature(vdev, VIRTIO_BALLOON_F_MUST_TELL_HOST);
@@ -195,6 +197,7 @@ static void leak_balloon(struct virtio_balloon *vb, size_t num)
                 tell_host(vb, vb->deflate_vq);
         mutex_unlock(&vb->balloon_lock);
         release_pages_by_pfn(vb->pfns, vb->num_pfns);
+        return num_freed_pages;
 }
 
 static inline void update_stat(struct virtio_balloon *vb, int idx,