The current implementation only deflates 256 pages even when a user
specifies more than that via the oom_pages module param. This patch
enables the deflating of up to oom_pages pages if there are enough
inflated pages.
Signed-off-by: Wei Wang <wei.w.wang@xxxxxxxxx>
Cc: Michael S. Tsirkin <mst@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
---
drivers/virtio/virtio_balloon.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 1ecd15a..ab55cf8 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -43,8 +43,8 @@
#define OOM_VBALLOON_DEFAULT_PAGES 256
#define VIRTBALLOON_OOM_NOTIFY_PRIORITY 80
-static int oom_pages = OOM_VBALLOON_DEFAULT_PAGES;
-module_param(oom_pages, int, S_IRUSR | S_IWUSR);
+static unsigned int oom_pages = OOM_VBALLOON_DEFAULT_PAGES;
+module_param(oom_pages, uint, 0600);
MODULE_PARM_DESC(oom_pages, "pages to free on OOM");
#ifdef CONFIG_BALLOON_COMPACTION
@@ -359,16 +359,20 @@ static int virtballoon_oom_notify(struct notifier_block *self,
{
struct virtio_balloon *vb;
unsigned long *freed;
- unsigned num_freed_pages;
+ unsigned int npages = oom_pages;
vb = container_of(self, struct virtio_balloon, nb);
if (!virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_DEFLATE_ON_OOM))
return NOTIFY_OK;
freed = parm;
- num_freed_pages = leak_balloon(vb, oom_pages);
+
+ /* Don't deflate more than the number of inflated pages */
+ while (npages && atomic64_read(&vb->num_pages))
+ npages -= leak_balloon(vb, npages);
+
update_balloon_size(vb);
- *freed += num_freed_pages;
+ *freed += oom_pages - npages;
return NOTIFY_OK;
}
--
2.7.4
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