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>

diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index c9703d4d6f676d8f4922462b6070e7c869d65f77..ff71fdcf33458954feecbb62d8b9d90534b39334 100644 (file)
--- 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,