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33 #ifndef _VIRTIO_BALLOON_H
34 #define _VIRTIO_BALLOON_H
37 #define VIRTIO_BALLOON_F_MUST_TELL_HOST 0x1 /* Tell before reclaiming pages */
38 #define VIRTIO_BALLOON_F_STATS_VQ 0x2 /* Memory stats virtqueue */
39 #define VIRTIO_BALLOON_F_DEFLATE_ON_OOM 0x4 /* Deflate balloon on OOM */
41 /* Size of a PFN in the balloon interface. */
42 #define VIRTIO_BALLOON_PFN_SHIFT 12
44 struct virtio_balloon_config {
45 /* Number of pages host wants Guest to give up. */
48 /* Number of pages we've actually got in balloon. */
52 #define VIRTIO_BALLOON_S_SWAP_IN 0 /* Amount of memory swapped in */
53 #define VIRTIO_BALLOON_S_SWAP_OUT 1 /* Amount of memory swapped out */
54 #define VIRTIO_BALLOON_S_MAJFLT 2 /* Number of major faults */
55 #define VIRTIO_BALLOON_S_MINFLT 3 /* Number of minor faults */
56 #define VIRTIO_BALLOON_S_MEMFREE 4 /* Total amount of free memory */
57 #define VIRTIO_BALLOON_S_MEMTOT 5 /* Total amount of memory */
58 #define VIRTIO_BALLOON_S_AVAIL 6 /* Available memory as in /proc */
59 #define VIRTIO_BALLOON_S_CACHES 7 /* Disk caches */
60 #define VIRTIO_BALLOON_S_NR 8
63 * Memory statistics structure.
64 * Driver fills an array of these structures and passes to device.
66 * NOTE: fields are laid out in a way that would make compiler add padding
67 * between and after fields, so we have to use compiler-specific attributes to
68 * pack it, to disable this padding. This also often causes compiler to
69 * generate suboptimal code.
71 * We maintain this statistics structure format for backwards compatibility,
72 * but don't follow this example.
74 * If implementing a similar structure, do something like the below instead:
75 * struct virtio_balloon_stat {
81 * In other words, add explicit reserved fields to align field and
82 * structure boundaries at field size, avoiding compiler padding
83 * without the packed attribute.
85 struct virtio_balloon_stat {
90 #endif /* _VIRTIO_BALLOON_H */