From: Igor Redko <redkoi@xxxxxxxxxxxxx>
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@xxxxxxxxxxxxx>
Reviewed-by: Roman Kagan <rkagan@xxxxxxxxxxxxx>
Signed-off-by: Denis V. Lunev <den@xxxxxxxxxx>
CC: Michael S. Tsirkin <mst@xxxxxxxxxx>
CC: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/virtio/virtio_balloon.c | 6 ++++++
include/uapi/linux/virtio_balloon.h | 3 ++-
2 files changed, 8 insertions(+), 1 deletion(-)
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 @@ static void update_balloon_stats(struct virtio_balloon *vb)
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 @@ static void update_balloon_stats(struct virtio_balloon *vb)
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));
}
/*
diff --git a/include/uapi/linux/virtio_balloon.h b/include/uapi/linux/virtio_balloon.h
index d7f1cbc..343d7dd 100644
--- a/include/uapi/linux/virtio_balloon.h
+++ b/include/uapi/linux/virtio_balloon.h
@@ -51,7 +51,8 @@ struct virtio_balloon_config {
#define VIRTIO_BALLOON_S_MINFLT 3 /* Number of minor faults */
#define VIRTIO_BALLOON_S_MEMFREE 4 /* Total amount of free memory */
#define VIRTIO_BALLOON_S_MEMTOT 5 /* Total amount of memory */
-#define VIRTIO_BALLOON_S_NR 6
+#define VIRTIO_BALLOON_S_AVAIL 6 /* Available memory as in /proc */
+#define VIRTIO_BALLOON_S_NR 7
/*
* Memory statistics structure.
--
2.5.0
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