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[Qemu-devel] [PATCH 6/8] Add event notification for guest balloon change
From: |
Luiz Capitulino |
Subject: |
[Qemu-devel] [PATCH 6/8] Add event notification for guest balloon changes |
Date: |
Fri, 15 Jun 2012 14:10:03 -0300 |
From: "Daniel P. Berrange" <address@hidden>
After setting a balloon target value, applications have to
continually poll 'query-balloon' to determine whether the
guest has reacted to this request. The virtio-balloon backend
knows exactly when the guest has reacted though, and thus it
is possible to emit a JSON event to tell the mgmt application
whenever the guest balloon changes.
This introduces a new 'qemu_balloon_changed()' API which is
to be called by balloon driver backends, whenever they have
a change in balloon value. This takes the 'actual' balloon
value, as would be found in the BalloonInfo struct.
The qemu_balloon_change API emits a JSON monitor event which
looks like:
{"timestamp": {"seconds": 1337162462, "microseconds": 814521},
"event": "BALLOON_CHANGE", "data": {"actual": 944766976}}
* balloon.c, balloon.h: Introduce qemu_balloon_changed() for
emitting balloon change events on the monitor
* hw/virtio-balloon.c: Invoke qemu_balloon_changed() whenever
the guest changes the balloon actual value
* monitor.c, monitor.h: Define QEVENT_BALLOON_CHANGE
Signed-off-by: Daniel P. Berrange <address@hidden>
Acked-by: Amit Shah <address@hidden>
Signed-off-by: Luiz Capitulino <address@hidden>
---
QMP/qmp-events.txt | 18 ++++++++++++++++++
balloon.c | 14 ++++++++++++++
balloon.h | 2 ++
hw/virtio-balloon.c | 5 +++++
monitor.c | 1 +
monitor.h | 1 +
6 files changed, 41 insertions(+)
diff --git a/QMP/qmp-events.txt b/QMP/qmp-events.txt
index 9286af5..9ba7079 100644
--- a/QMP/qmp-events.txt
+++ b/QMP/qmp-events.txt
@@ -335,3 +335,21 @@ Example:
"len": 10737418240, "offset": 134217728,
"speed": 0 },
"timestamp": { "seconds": 1267061043, "microseconds": 959568 } }
+
+
+BALLOON_CHANGE
+----------
+
+Emitted when the guest changes the actual BALLOON level. This
+value is equivalent to the 'actual' field return by the
+'query-balloon' command
+
+Data:
+
+- "actual": actual level of the guest memory balloon in bytes (json-number)
+
+Example:
+
+{ "event": "BALLOON_CHANGE",
+ "data": { "actual": 944766976 },
+ "timestamp": { "seconds": 1267020223, "microseconds": 435656 } }
diff --git a/balloon.c b/balloon.c
index aa354f7..e02ab1c 100644
--- a/balloon.c
+++ b/balloon.c
@@ -30,6 +30,7 @@
#include "balloon.h"
#include "trace.h"
#include "qmp-commands.h"
+#include "qjson.h"
static QEMUBalloonEvent *balloon_event_fn;
static QEMUBalloonStatus *balloon_stat_fn;
@@ -80,6 +81,19 @@ static int qemu_balloon_status(BalloonInfo *info)
return 1;
}
+void qemu_balloon_changed(int64_t actual)
+{
+ QObject *data;
+
+ data = qobject_from_jsonf("{ 'actual': %" PRId64 " }",
+ actual);
+
+ monitor_protocol_event(QEVENT_BALLOON_CHANGE, data);
+
+ qobject_decref(data);
+}
+
+
BalloonInfo *qmp_query_balloon(Error **errp)
{
BalloonInfo *info;
diff --git a/balloon.h b/balloon.h
index b60fd5d..b803a00 100644
--- a/balloon.h
+++ b/balloon.h
@@ -24,4 +24,6 @@ int qemu_add_balloon_handler(QEMUBalloonEvent *event_func,
QEMUBalloonStatus *stat_func, void *opaque);
void qemu_remove_balloon_handler(void *opaque);
+void qemu_balloon_changed(int64_t actual);
+
#endif
diff --git a/hw/virtio-balloon.c b/hw/virtio-balloon.c
index 075ed87..d048cef 100644
--- a/hw/virtio-balloon.c
+++ b/hw/virtio-balloon.c
@@ -146,8 +146,13 @@ static void virtio_balloon_set_config(VirtIODevice *vdev,
{
VirtIOBalloon *dev = to_virtio_balloon(vdev);
struct virtio_balloon_config config;
+ uint32_t oldactual = dev->actual;
memcpy(&config, config_data, 8);
dev->actual = le32_to_cpu(config.actual);
+ if (dev->actual != oldactual) {
+ qemu_balloon_changed(ram_size -
+ (dev->actual << VIRTIO_BALLOON_PFN_SHIFT));
+ }
}
static uint32_t virtio_balloon_get_features(VirtIODevice *vdev, uint32_t f)
diff --git a/monitor.c b/monitor.c
index a3bc2c7..75fd4cf 100644
--- a/monitor.c
+++ b/monitor.c
@@ -443,6 +443,7 @@ static const char *monitor_event_names[] = {
[QEVENT_DEVICE_TRAY_MOVED] = "DEVICE_TRAY_MOVED",
[QEVENT_SUSPEND] = "SUSPEND",
[QEVENT_WAKEUP] = "WAKEUP",
+ [QEVENT_BALLOON_CHANGE] = "BALLOON_CHANGE",
};
QEMU_BUILD_BUG_ON(ARRAY_SIZE(monitor_event_names) != QEVENT_MAX)
diff --git a/monitor.h b/monitor.h
index cd1d878..5f4de1b 100644
--- a/monitor.h
+++ b/monitor.h
@@ -41,6 +41,7 @@ typedef enum MonitorEvent {
QEVENT_DEVICE_TRAY_MOVED,
QEVENT_SUSPEND,
QEVENT_WAKEUP,
+ QEVENT_BALLOON_CHANGE,
/* Add to 'monitor_event_names' array in monitor.c when
* defining new events here */
--
1.7.10.2.565.gbd578b5
- [Qemu-devel] [PULL 0/8]: QMP queue, Luiz Capitulino, 2012/06/15
- [Qemu-devel] [PATCH 1/8] kvm: add missing include files, Luiz Capitulino, 2012/06/15
- [Qemu-devel] [PATCH 3/8] qmp: do not include monitor.h from qapi-types-core.h, Luiz Capitulino, 2012/06/15
- [Qemu-devel] [PATCH 2/8] qmp: include monitor.h when needed, Luiz Capitulino, 2012/06/15
- [Qemu-devel] [PATCH 4/8] monitor: Fix memory leak with readline completion, Luiz Capitulino, 2012/06/15
- [Qemu-devel] [PATCH 6/8] Add event notification for guest balloon changes,
Luiz Capitulino <=
- [Qemu-devel] [PATCH 5/8] Fix some more license versions (GPL2+ instead of GPL2), Luiz Capitulino, 2012/06/15
- [Qemu-devel] [PATCH 8/8] build: install qmp-commands.txt, Luiz Capitulino, 2012/06/15
- [Qemu-devel] [PATCH 7/8] Add rate limiting of RTC_CHANGE, BALLOON_CHANGE & WATCHDOG events, Luiz Capitulino, 2012/06/15
- Re: [Qemu-devel] [PULL 0/8]: QMP queue, Anthony Liguori, 2012/06/20