include/uapi/linux/virtio_balloon.h

   1 #ifndef _LINUX_VIRTIO_BALLOON_H
   2 #define _LINUX_VIRTIO_BALLOON_H
   3 /* This header is BSD licensed so anyone can use the definitions to implement
   4  * compatible drivers/servers.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  * 3. Neither the name of IBM nor the names of its contributors
  15  *    may be used to endorse or promote products derived from this software
  16  *    without specific prior written permission.
  17  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE. */
  28 #include <linux/types.h>
  29 #include <linux/virtio_types.h>
  30 #include <linux/virtio_ids.h>
  31 #include <linux/virtio_config.h>
  32
  33 /* The feature bitmap for virtio balloon */
  34 #define VIRTIO_BALLOON_F_MUST_TELL_HOST 0 /* Tell before reclaiming pages */
  35 #define VIRTIO_BALLOON_F_STATS_VQ       1 /* Memory Stats virtqueue */
  36 #define VIRTIO_BALLOON_F_DEFLATE_ON_OOM 2 /* Deflate balloon on OOM */
  37 #define VIRTIO_BALLOON_F_FREE_PAGE_HINT 3 /* VQ to report free pages */
  38 #define VIRTIO_BALLOON_F_PAGE_POISON    4 /* Guest is using page poisoning */
  39 #define VIRTIO_BALLOON_F_REPORTING      5 /* Page reporting virtqueue */
  40
  41 /* Size of a PFN in the balloon interface. */
  42 #define VIRTIO_BALLOON_PFN_SHIFT 12
  43
  44 #define VIRTIO_BALLOON_CMD_ID_STOP      0
  45 #define VIRTIO_BALLOON_CMD_ID_DONE      1
  46 struct virtio_balloon_config {
  47         /* Number of pages host wants Guest to give up. */
  48         __le32 num_pages;
  49         /* Number of pages we've actually got in balloon. */
  50         __le32 actual;
  51         /*
  52          * Free page hint command id, readonly by guest.
  53          * Was previously named free_page_report_cmd_id so we
  54          * need to carry that name for legacy support.
  55          */
  56         union {
  57                 __le32 free_page_hint_cmd_id;
  58                 __le32 free_page_report_cmd_id; /* deprecated */
  59         };
  60         /* Stores PAGE_POISON if page poisoning is in use */
  61         __le32 poison_val;
  62 };
  63
  64 #define VIRTIO_BALLOON_S_SWAP_IN  0   /* Amount of memory swapped in */
  65 #define VIRTIO_BALLOON_S_SWAP_OUT 1   /* Amount of memory swapped out */
  66 #define VIRTIO_BALLOON_S_MAJFLT   2   /* Number of major faults */
  67 #define VIRTIO_BALLOON_S_MINFLT   3   /* Number of minor faults */
  68 #define VIRTIO_BALLOON_S_MEMFREE  4   /* Total amount of free memory */
  69 #define VIRTIO_BALLOON_S_MEMTOT   5   /* Total amount of memory */
  70 #define VIRTIO_BALLOON_S_AVAIL    6   /* Available memory as in /proc */
  71 #define VIRTIO_BALLOON_S_CACHES   7   /* Disk caches */
  72 #define VIRTIO_BALLOON_S_HTLB_PGALLOC  8  /* Hugetlb page allocations */
  73 #define VIRTIO_BALLOON_S_HTLB_PGFAIL   9  /* Hugetlb page allocation failures */
  74 #define VIRTIO_BALLOON_S_OOM_KILL      10 /* OOM killer invocations */
  75 #define VIRTIO_BALLOON_S_ALLOC_STALL   11 /* Stall count of memory allocatoin */
  76 #define VIRTIO_BALLOON_S_ASYNC_SCAN    12 /* Amount of memory scanned asynchronously */
  77 #define VIRTIO_BALLOON_S_DIRECT_SCAN   13 /* Amount of memory scanned directly */
  78 #define VIRTIO_BALLOON_S_ASYNC_RECLAIM 14 /* Amount of memory reclaimed asynchronously */
  79 #define VIRTIO_BALLOON_S_DIRECT_RECLAIM 15 /* Amount of memory reclaimed directly */
  80 #define VIRTIO_BALLOON_S_NR       16
  81
  82 #define VIRTIO_BALLOON_S_NAMES_WITH_PREFIX(VIRTIO_BALLOON_S_NAMES_prefix) { \
  83         VIRTIO_BALLOON_S_NAMES_prefix "swap-in", \
  84         VIRTIO_BALLOON_S_NAMES_prefix "swap-out", \
  85         VIRTIO_BALLOON_S_NAMES_prefix "major-faults", \
  86         VIRTIO_BALLOON_S_NAMES_prefix "minor-faults", \
  87         VIRTIO_BALLOON_S_NAMES_prefix "free-memory", \
  88         VIRTIO_BALLOON_S_NAMES_prefix "total-memory", \
  89         VIRTIO_BALLOON_S_NAMES_prefix "available-memory", \
  90         VIRTIO_BALLOON_S_NAMES_prefix "disk-caches", \
  91         VIRTIO_BALLOON_S_NAMES_prefix "hugetlb-allocations", \
  92         VIRTIO_BALLOON_S_NAMES_prefix "hugetlb-failures", \
  93         VIRTIO_BALLOON_S_NAMES_prefix "oom-kills", \
  94         VIRTIO_BALLOON_S_NAMES_prefix "alloc-stalls", \
  95         VIRTIO_BALLOON_S_NAMES_prefix "async-scans", \
  96         VIRTIO_BALLOON_S_NAMES_prefix "direct-scans", \
  97         VIRTIO_BALLOON_S_NAMES_prefix "async-reclaims", \
  98         VIRTIO_BALLOON_S_NAMES_prefix "direct-reclaims" \
  99 }
 100
 101 #define VIRTIO_BALLOON_S_NAMES VIRTIO_BALLOON_S_NAMES_WITH_PREFIX("")
 102
 103 /*
 104  * Memory statistics structure.
 105  * Driver fills an array of these structures and passes to device.
 106  *
 107  * NOTE: fields are laid out in a way that would make compiler add padding
 108  * between and after fields, so we have to use compiler-specific attributes to
 109  * pack it, to disable this padding. This also often causes compiler to
 110  * generate suboptimal code.
 111  *
 112  * We maintain this statistics structure format for backwards compatibility,
 113  * but don't follow this example.
 114  *
 115  * If implementing a similar structure, do something like the below instead:
 116  *     struct virtio_balloon_stat {
 117  *         __virtio16 tag;
 118  *         __u8 reserved[6];
 119  *         __virtio64 val;
 120  *     };
 121  *
 122  * In other words, add explicit reserved fields to align field and
 123  * structure boundaries at field size, avoiding compiler padding
 124  * without the packed attribute.
 125  */
 126 struct virtio_balloon_stat {
 127         __virtio16 tag;
 128         __virtio64 val;
 129 } __attribute__((packed));
 130
 131 #endif /* _LINUX_VIRTIO_BALLOON_H */