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>
This commit is contained in:
Igor Redko 2016-03-17 14:19:08 -07:00 committed by Linus Torvalds
parent d02bd27bd3
commit 5057dcd0f1
2 changed files with 8 additions and 1 deletions

View File

@ -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));
}
/*

View File

@ -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.