--- /dev/null
+From: Luiz Capitulino <lcapitulino@redhat.com>
+Subject: [Qemu-devel] [PATCH 3/3] docs: document virtio-balloon stats
+
+Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
+---
+ docs/virtio-balloon-stats.txt | 87 +++++++++++++++++++++++++++++++++++++++++++
+ 1 file changed, 87 insertions(+)
+ create mode 100644 docs/virtio-balloon-stats.txt
+
+diff --git a/docs/virtio-balloon-stats.txt b/docs/virtio-balloon-stats.txt
+new file mode 100644
+index 0000000..139e74d
+--- /dev/null
++++ b/docs/virtio-balloon-stats.txt
+@@ -0,0 +1,87 @@
++virtio balloon memory statistics
++================================
++
++The virtio balloon driver supports guest memory statistics reporting. These
++statistics are available to QEMU users as QOM (QEMU Object Model) device
++properties via a polling mechanism.
++
++Basically, clients first have to enable polling, then they can query the
++available statistics.
++
++There are two control properties and six memory statistics properties.
++
++The control properties are:
++
++ o stats-polling-interval: polling time interval in seconds, it can be:
++
++ > 0 enables polling in the specified interval. If polling is already
++ enabled, the polling time interval will be changed to the new value
++
++ 0 disables polling. Previous polled statistics are still valid and
++ can be queried.
++
++ o stats-last-update: last stats update timestamp, in seconds
++
++The following statistics are available, all values are in bytes:
++
++ o stat-swap-in
++ o stat-swap-out
++ o stat-major-faults
++ o stat-minor-faults
++ o stat-free-memory
++ o stat-total-memory
++
++Also, please note the following:
++
++ - If a statistic is queried before the timer is enabled or if the guest
++ doesn't support a particular statistic, an error will be returned
++
++ - Previously polled statistics remain available even if the timer is
++ later disabled
++
++ - The polling timer is only re-armed when the guest answers to the
++ statistics request. This means that if the guest takes too long to
++ respond (say, a few seconds) this delay will end up being added to the
++ poll interval. Also, if a (buggy) guest doesn't ever respond, the
++ statistics won't get updated and the timer disarmed
++
++Here are a few examples. The virtio-balloon device is assumed to be in the
++'/machine/peripheral-anon/device[1]' QOM path.
++
++Enable polling with 2 seconds interval:
++
++{ "execute": "qom-set",
++ "arguments": { "path": "/machine/peripheral-anon/device[1]",
++ "property": "stats-polling-interval", "value": 2 } }
++
++{ "return": {} }
++
++Change polling to 10 seconds:
++
++{ "execute": "qom-set",
++ "arguments": { "path": "/machine/peripheral-anon/device[1]",
++ "property": "stats-polling-interval", "value": 10 } }
++
++{ "return": {} }
++
++Get last update timestamp and free memory stat:
++
++{ "execute": "qom-get",
++ "arguments": { "path": "/machine/peripheral-anon/device[1]",
++ "property": "stats-last-update" } }
++
++{ "return": 1354629634 }
++
++{ "execute": "qom-get",
++ "arguments": { "path": "/machine/peripheral-anon/device[1]",
++ "property": "stat-free-memory" } }
++
++{ "return": 845115392 }
++
++Disable polling:
++
++{ "execute": "qom-set",
++ "arguments": { "path": "/machine/peripheral-anon/device[1]",
++ "property": "stats-polling-interval", "value": 0 } }
++
++{ "return": {} }
+--
+1.8.0
+
+
+
+
--- /dev/null
+From: Luiz Capitulino <lcapitulino@redhat.com>
+Subject: [Qemu-devel] [PATCH 2/3] virtio-balloon: re-enable balloon stats
+
+The statistics are now available through device properties via a
+polling mechanism. First a client has to enable polling, then it
+can query each stat individually.
+
+The following control properties are introduced:
+
+ o stats-polling-interval: a value greater than zero enables polling
+ in the specified interval (in seconds). When value equals zero,
+ polling is disabled. If polling is already enabled and a value
+ greater than zero is written, the polling interval time is changed
+
+ o stats-last-update: last stats update timestamp, in seconds.
+
+The following stats properties are introduced, all values are in bytes:
+
+ o stat-swap-in
+ o stat-swap-out
+ o stat-major-faults
+ o stat-minor-faults
+ o stat-free-memory
+ o stat-total-memory
+
+Please, refer to the documentation introduced by the next commit for
+more information and examples.
+
+Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
+---
+ hw/virtio-balloon.c | 167 +++++++++++++++++++++++++++++++++++++++++++++++++++-
+ 1 file changed, 165 insertions(+), 2 deletions(-)
+
+diff --git a/hw/virtio-balloon.c b/hw/virtio-balloon.c
+index 4398025..4bab2ae 100644
+--- a/hw/virtio-balloon.c
++++ b/hw/virtio-balloon.c
+@@ -22,6 +22,8 @@
+ #include "virtio-balloon.h"
+ #include "kvm.h"
+ #include "exec-memory.h"
++#include "qemu-timer.h"
++#include "qapi/qapi-visit-core.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 +82,127 @@ 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;
++
++ virtqueue_push(s->svq, &s->stats_vq_elem, s->stats_vq_offset);
++ virtio_notify(&s->vdev, s->svq);
++}
++
++static void balloon_stats_get_last_update(Object *obj, struct Visitor *v,
++ void *opaque, const char *name,
++ Error **errp)
++{
++ VirtIOBalloon *s = opaque;
++ visit_type_int(v, &s->stats_last_update, name, errp);
++}
++
++static void balloon_stats_get_stat(Object *obj, struct Visitor *v,
++ void *opaque, const char *name, Error **errp)
++{
++ VirtIOBalloon *s = opaque;
++ int i;
++
++ for (i = 0; i < VIRTIO_BALLOON_S_NR; i++) {
++ if (!strcmp(balloon_stat_names[i], name)) {
++ break;
++ }
++ }
++
++ if (i == VIRTIO_BALLOON_S_NR) {
++ error_setg(errp, "invalid stat name '%s'", name);
++ return;
++ }
++
++ if (s->stats[i] == -1) {
++ error_setg(errp,
++ "timer hasn't been enabled or guest doesn't support '%s'", name);
++ return;
++ }
++
++ visit_type_int(v, (int64_t *) &s->stats[i], name, 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;
++
++ if (!balloon_stats_supported(s)) {
++ error_setg(errp, "guest doesn\'t support balloon stats");
++ return;
++ }
++
++ visit_type_int(v, &value, name, errp);
++ if (error_is_set(errp)) {
++ return;
++ }
++
++ if (value < 0) {
++ error_setg(errp, "timer value must be positive");
++ 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 +243,10 @@ 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 +265,18 @@ 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)
+@@ -212,7 +361,7 @@ static int virtio_balloon_load(QEMUFile *f, void *opaque, int version_id)
+ VirtIODevice *virtio_balloon_init(DeviceState *dev)
+ {
+ VirtIOBalloon *s;
+- int ret;
++ int i, ret;
+
+ s = (VirtIOBalloon *)virtio_common_init("virtio-balloon",
+ VIRTIO_ID_BALLOON,
+@@ -239,6 +388,19 @@ VirtIODevice *virtio_balloon_init(DeviceState *dev)
+ register_savevm(dev, "virtio-balloon", -1, 1,
+ virtio_balloon_save, virtio_balloon_load, s);
+
++ for (i = 0; i < VIRTIO_BALLOON_S_NR; i++) {
++ object_property_add(OBJECT(dev), balloon_stat_names[i], "int",
++ balloon_stats_get_stat, NULL, NULL, s, NULL);
++ }
++
++ object_property_add(OBJECT(dev), "stats-last-update", "int",
++ balloon_stats_get_last_update, NULL, NULL, s, NULL);
++
++ object_property_add(OBJECT(dev), "stats-polling-interval", "int",
++ balloon_stats_get_poll_interval,
++ balloon_stats_set_poll_interval,
++ NULL, s, NULL);
++
+ return &s->vdev;
+ }
+
+@@ -246,6 +408,7 @@ 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);
+--
+1.8.0
+
+
+
+
projects / pve-qemu-kvm.git / commitdiff