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balloon: re-enable balloon stats

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The statistics are now available through device properties via a
polling mechanism. First a client has to enable polling, then it
can query available stats.

Polling is enabled by setting an update interval (in seconds)
to a property named guest-stats-polling-interval, like this:

{ "execute": "qom-set",
  "arguments": { "path": "/machine/peripheral-anon/device[1]",
                 "property": "guest-stats-polling-interval", "value": 4 } }

Then the available stats can be retrieved by querying the
guest-stats property. The returned object is a dict containing
all available stats. Example:

{ "execute": "qom-get",
  "arguments": { "path": "/machine/peripheral-anon/device[1]",
  "property": "guest-stats" } }

{
    "return": {
        "stats": {
            "stat-swap-out": 0,
            "stat-free-memory": 844943360,
            "stat-minor-faults": 219028,
            "stat-major-faults": 235,
            "stat-total-memory": 1044406272,
            "stat-swap-in": 0
        },
        "last-update": 1358529861
    }
}

Please, check the next commit for full documentation.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
This commit is contained in:
Luiz Capitulino 2012-12-01 00:14:57 -02:00
parent 01ceb97e7b
commit 7e6ccd9c15
1 changed files with 150 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

151
hw/virtio-balloon.c
View File

@ -14,6 +14,7 @@
*/
#include "qemu/iov.h"
#include "qemu/timer.h"
#include "qemu-common.h"
#include "virtio.h"
#include "pc.h"
@ -22,6 +23,7 @@
#include "virtio-balloon.h"
#include "sysemu/kvm.h"
#include "exec/address-spaces.h"
#include "qapi/visitor.h"
#if defined(__linux__)
#include <sys/mman.h>
@ -36,6 +38,9 @@ typedef struct VirtIOBalloon
uint64_t stats[VIRTIO_BALLOON_S_NR];
VirtQueueElement stats_vq_elem;
size_t stats_vq_offset;
QEMUTimer *stats_timer;
int64_t stats_last_update;
int64_t stats_poll_interval;
DeviceState *qdev;
} VirtIOBalloon;
@ -53,6 +58,16 @@ static void balloon_page(void *addr, int deflate)
#endif
}
static const char *balloon_stat_names[] = {
[VIRTIO_BALLOON_S_SWAP_IN] = "stat-swap-in",
[VIRTIO_BALLOON_S_SWAP_OUT] = "stat-swap-out",
[VIRTIO_BALLOON_S_MAJFLT] = "stat-major-faults",
[VIRTIO_BALLOON_S_MINFLT] = "stat-minor-faults",
[VIRTIO_BALLOON_S_MEMFREE] = "stat-free-memory",
[VIRTIO_BALLOON_S_MEMTOT] = "stat-total-memory",
[VIRTIO_BALLOON_S_NR] = NULL
};
/*
* reset_stats - Mark all items in the stats array as unset
*
@ -67,6 +82,118 @@ static inline void reset_stats(VirtIOBalloon *dev)
for (i = 0; i < VIRTIO_BALLOON_S_NR; dev->stats[i++] = -1);
}
static bool balloon_stats_supported(const VirtIOBalloon *s)
{
return s->vdev.guest_features & (1 << VIRTIO_BALLOON_F_STATS_VQ);
}
static bool balloon_stats_enabled(const VirtIOBalloon *s)
{
return s->stats_poll_interval > 0;
}
static void balloon_stats_destroy_timer(VirtIOBalloon *s)
{
if (balloon_stats_enabled(s)) {
qemu_del_timer(s->stats_timer);
qemu_free_timer(s->stats_timer);
s->stats_timer = NULL;
s->stats_poll_interval = 0;
}
}
static void balloon_stats_change_timer(VirtIOBalloon *s, int secs)
{
qemu_mod_timer(s->stats_timer, qemu_get_clock_ms(vm_clock) + secs * 1000);
}
static void balloon_stats_poll_cb(void *opaque)
{
VirtIOBalloon *s = opaque;
if (!balloon_stats_supported(s)) {
/* re-schedule */
balloon_stats_change_timer(s, s->stats_poll_interval);
return;
}
virtqueue_push(s->svq, &s->stats_vq_elem, s->stats_vq_offset);
virtio_notify(&s->vdev, s->svq);
}
static void balloon_stats_get_all(Object *obj, struct Visitor *v,
void *opaque, const char *name, Error **errp)
{
VirtIOBalloon *s = opaque;
int i;
if (!s->stats_last_update) {
error_setg(errp, "guest hasn't updated any stats yet");
return;
}
visit_start_struct(v, NULL, "guest-stats", name, 0, errp);
visit_type_int(v, &s->stats_last_update, "last-update", errp);
visit_start_struct(v, NULL, NULL, "stats", 0, errp);
for (i = 0; i < VIRTIO_BALLOON_S_NR; i++) {
visit_type_int64(v, (int64_t *) &s->stats[i], balloon_stat_names[i],
errp);
}
visit_end_struct(v, errp);
visit_end_struct(v, errp);
}
static void balloon_stats_get_poll_interval(Object *obj, struct Visitor *v,
void *opaque, const char *name,
Error **errp)
{
VirtIOBalloon *s = opaque;
visit_type_int(v, &s->stats_poll_interval, name, errp);
}
static void balloon_stats_set_poll_interval(Object *obj, struct Visitor *v,
void *opaque, const char *name,
Error **errp)
{
VirtIOBalloon *s = opaque;
int64_t value;
visit_type_int(v, &value, name, errp);
if (error_is_set(errp)) {
return;
}
if (value < 0) {
error_setg(errp, "timer value must be greater than zero");
return;
}
if (value == s->stats_poll_interval) {
return;
}
if (value == 0) {
/* timer=0 disables the timer */
balloon_stats_destroy_timer(s);
return;
}
if (balloon_stats_enabled(s)) {
/* timer interval change */
s->stats_poll_interval = value;
balloon_stats_change_timer(s, value);
return;
}
/* create a new timer */
g_assert(s->stats_timer == NULL);
s->stats_timer = qemu_new_timer_ms(vm_clock, balloon_stats_poll_cb, s);
s->stats_poll_interval = value;
balloon_stats_change_timer(s, 0);
}
static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq)
{
VirtIOBalloon *s = to_virtio_balloon(vdev);
@ -107,9 +234,10 @@ static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq)
VirtQueueElement *elem = &s->stats_vq_elem;
VirtIOBalloonStat stat;
size_t offset = 0;
qemu_timeval tv;
if (!virtqueue_pop(vq, elem)) {
return;
goto out;
}
/* Initialize the stats to get rid of any stale values. This is only
@ -128,6 +256,18 @@ static void virtio_balloon_receive_stats(VirtIODevice *vdev, VirtQueue *vq)
s->stats[tag] = val;
}
s->stats_vq_offset = offset;
if (qemu_gettimeofday(&tv) < 0) {
fprintf(stderr, "warning: %s: failed to get time of day\n", __func__);
goto out;
}
s->stats_last_update = tv.tv_sec;
out:
if (balloon_stats_enabled(s)) {
balloon_stats_change_timer(s, s->stats_poll_interval);
}
}
static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data)
@ -237,6 +377,14 @@ VirtIODevice *virtio_balloon_init(DeviceState *dev)
register_savevm(dev, "virtio-balloon", -1, 1,
virtio_balloon_save, virtio_balloon_load, s);
object_property_add(OBJECT(dev), "guest-stats", "guest statistics",
balloon_stats_get_all, NULL, NULL, s, NULL);
object_property_add(OBJECT(dev), "guest-stats-polling-interval", "int",
balloon_stats_get_poll_interval,
balloon_stats_set_poll_interval,
NULL, s, NULL);
return &s->vdev;
}
@ -244,6 +392,7 @@ void virtio_balloon_exit(VirtIODevice *vdev)
{
VirtIOBalloon *s = DO_UPCAST(VirtIOBalloon, vdev, vdev);
balloon_stats_destroy_timer(s);
qemu_remove_balloon_handler(s);
unregister_savevm(s->qdev, "virtio-balloon", s);
virtio_cleanup(vdev);