virtio_balloon: export 'available' memory to balloon statistics
Add a new field, VIRTIO_BALLOON_S_AVAIL, to virtio_balloon memory
statistics protocol, corresponding to 'Available' in /proc/meminfo.
It indicates to the hypervisor how big the balloon can be inflated
without pushing the guest system to swap.
Signed-off-by: Igor Redko <redkoi@virtuozzo.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 0c3691f..f2b77de 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -30,6 +30,7 @@
#include <linux/balloon_compaction.h>
#include <linux/oom.h>
#include <linux/wait.h>
+#include <linux/mm.h>
/*
* Balloon device works in 4K page units. So each page is pointed to by
@@ -229,10 +230,13 @@
unsigned long events[NR_VM_EVENT_ITEMS];
struct sysinfo i;
int idx = 0;
+ long available;
all_vm_events(events);
si_meminfo(&i);
+ available = si_mem_available();
+
update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_IN,
pages_to_bytes(events[PSWPIN]));
update_stat(vb, idx++, VIRTIO_BALLOON_S_SWAP_OUT,
@@ -243,6 +247,8 @@
pages_to_bytes(i.freeram));
update_stat(vb, idx++, VIRTIO_BALLOON_S_MEMTOT,
pages_to_bytes(i.totalram));
+ update_stat(vb, idx++, VIRTIO_BALLOON_S_AVAIL,
+ pages_to_bytes(available));
}
/*
