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Commit 5057dcd0 authored by Igor Redko's avatar Igor Redko Committed by Linus Torvalds
Browse files

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: default avatarIgor Redko <redkoi@virtuozzo.com>
Signed-off-by: default avatarDenis V. Lunev <den@openvz.org>
Reviewed-by: default avatarRoman Kagan <rkagan@virtuozzo.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d02bd27b

drivers/virtio/virtio_balloon.c

+6 −0
Original line number Diff line number Diff line
@@ -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));

}



/*

include/uapi/linux/virtio_balloon.h

+2 −1
Original line number Diff line number Diff line
@@ -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.