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diff --git a/sys/dev/virtio/balloon/virtio_balloon.h b/sys/dev/virtio/balloon/virtio_balloon.h
--- a/sys/dev/virtio/balloon/virtio_balloon.h
+++ b/sys/dev/virtio/balloon/virtio_balloon.h
@@ -36,6 +36,7 @@
/* Feature bits. */
#define VIRTIO_BALLOON_F_MUST_TELL_HOST 0x1 /* Tell before reclaiming pages */
#define VIRTIO_BALLOON_F_STATS_VQ 0x2 /* Memory stats virtqueue */
+#define VIRTIO_BALLOON_F_DEFLATE_ON_OOM 0x4 /* Deflate balloon on OOM */
/* Size of a PFN in the balloon interface. */
#define VIRTIO_BALLOON_PFN_SHIFT 12
@@ -54,8 +55,33 @@
#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_CACHES 7 /* Disk caches */
+#define VIRTIO_BALLOON_S_NR 8
+/*
+ * Memory statistics structure.
+ * Driver fills an array of these structures and passes to device.
+ *
+ * NOTE: fields are laid out in a way that would make compiler add padding
+ * between and after fields, so we have to use compiler-specific attributes to
+ * pack it, to disable this padding. This also often causes compiler to
+ * generate suboptimal code.
+ *
+ * We maintain this statistics structure format for backwards compatibility,
+ * but don't follow this example.
+ *
+ * If implementing a similar structure, do something like the below instead:
+ * struct virtio_balloon_stat {
+ * __virtio16 tag;
+ * __u8 reserved[6];
+ * __virtio64 val;
+ * };
+ *
+ * In other words, add explicit reserved fields to align field and
+ * structure boundaries at field size, avoiding compiler padding
+ * without the packed attribute.
+ */
struct virtio_balloon_stat {
uint16_t tag;
uint64_t val;
diff --git a/sys/dev/virtio/balloon/virtio_balloon.c b/sys/dev/virtio/balloon/virtio_balloon.c
--- a/sys/dev/virtio/balloon/virtio_balloon.c
+++ b/sys/dev/virtio/balloon/virtio_balloon.c
@@ -80,6 +80,8 @@
static struct virtio_feature_desc vtballoon_feature_desc[] = {
{ VIRTIO_BALLOON_F_MUST_TELL_HOST, "MustTellHost" },
{ VIRTIO_BALLOON_F_STATS_VQ, "StatsVq" },
+ { VIRTIO_BALLOON_F_DEFLATE_ON_OOM, "DeflateOnOOM" },
+
{ 0, NULL }
};
@@ -110,8 +112,11 @@
static void vtballoon_thread(void *);
static void vtballoon_add_sysctl(struct vtballoon_softc *);
+#define vtballoon_modern(_sc) \
+ (((_sc)->vtballoon_features & VIRTIO_F_VERSION_1) != 0)
+
/* Features desired/implemented by this driver. */
-#define VTBALLOON_FEATURES 0
+#define VTBALLOON_FEATURES VIRTIO_BALLOON_F_MUST_TELL_HOST
/* Timeout between retries when the balloon needs inflating. */
#define VTBALLOON_LOWMEM_TIMEOUT hz
@@ -278,8 +283,10 @@
uint64_t features;
dev = sc->vtballoon_dev;
- features = virtio_negotiate_features(dev, VTBALLOON_FEATURES);
- sc->vtballoon_features = features;
+ features = VTBALLOON_FEATURES;
+
+ sc->vtballoon_features = virtio_negotiate_features(dev, features);
+ virtio_finalize_features(dev);
}
static int
@@ -440,7 +447,8 @@
{
vm_page_t m;
- m = vm_page_alloc(NULL, 0, VM_ALLOC_NORMAL | VM_ALLOC_NOOBJ);
+ m = vm_page_alloc(NULL, 0,
+ VM_ALLOC_NORMAL | VM_ALLOC_NOOBJ | VM_ALLOC_NODUMP);
if (m != NULL)
sc->vtballoon_current_npages++;
@@ -463,16 +471,23 @@
desired = virtio_read_dev_config_4(sc->vtballoon_dev,
offsetof(struct virtio_balloon_config, num_pages));
- return (le32toh(desired));
+ if (vtballoon_modern(sc))
+ return (desired);
+ else
+ return (le32toh(desired));
}
static void
vtballoon_update_size(struct vtballoon_softc *sc)
{
+ uint32_t npages;
+
+ npages = sc->vtballoon_current_npages;
+ if (!vtballoon_modern(sc))
+ npages = htole32(npages);
virtio_write_dev_config_4(sc->vtballoon_dev,
- offsetof(struct virtio_balloon_config, actual),
- htole32(sc->vtballoon_current_npages));
+ offsetof(struct virtio_balloon_config, actual), npages);
}
static int

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