This patch adds a timer to limit the time that host waits for the free
page hints reported by the guest. Users can specify the time in ms via
"free-page-wait-time" command line option. If a user doesn't specify a
time, host waits till the guest finishes reporting all the free page
hints. The policy (wait for all the free page hints to be reported or
use a time limit) is determined by the orchestration layer.
Signed-off-by: Wei Wang <wei.w.w...@intel.com>
CC: Michael S. Tsirkin <m...@redhat.com>
---
hw/virtio/virtio-balloon.c | 84 +++++++++++++++++++++++++++++++++++++-
hw/virtio/virtio-pci.c | 3 ++
include/hw/virtio/virtio-balloon.h | 4 ++
3 files changed, 90 insertions(+), 1 deletion(-)
diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
index b424d4e..9ee0de4 100644
--- a/hw/virtio/virtio-balloon.c
+++ b/hw/virtio/virtio-balloon.c
@@ -207,6 +207,65 @@ static void balloon_stats_set_poll_interval(Object *obj,
Visitor *v,
balloon_stats_change_timer(s, 0);
}
+static void balloon_free_page_change_timer(VirtIOBalloon *s, int64_t ms)
+{
+ timer_mod(s->free_page_timer,
+ qemu_clock_get_ms(QEMU_CLOCK_REALTIME) + ms);
+}
+
+static void balloon_stop_free_page_report(void *opaque)
+{
+ VirtIOBalloon *dev = opaque;
+ VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+
+ timer_del(dev->free_page_timer);
+ timer_free(dev->free_page_timer);
+ dev->free_page_timer = NULL;
+
+ if (dev->free_page_report_status == FREE_PAGE_REPORT_S_START) {
+ dev->host_stop_free_page = true;
+ virtio_notify_config(vdev);
+ }
+}
+
+static void balloon_free_page_get_wait_time(Object *obj, Visitor *v,
+ const char *name, void *opaque,
+ Error **errp)
+{
+ VirtIOBalloon *s = opaque;
+
+ visit_type_int(v, name, &s->free_page_wait_time, errp);
+}
+
+static void balloon_free_page_set_wait_time(Object *obj, Visitor *v,
+ const char *name, void *opaque,
+ Error **errp)
+{
+ VirtIOBalloon *s = opaque;
+ Error *local_err = NULL;
+ int64_t value;
+
+ visit_type_int(v, name, &value, &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
+ return;
+ }
+ if (value < 0) {
+ error_setg(errp, "free page wait time must be greater than zero");
+ return;
+ }
+
+ if (value > UINT32_MAX) {
+ error_setg(errp, "free page wait time value is too big");
+ return;
+ }
+
+ s->free_page_wait_time = value;
+ g_assert(s->free_page_timer == NULL);
+ s->free_page_timer = timer_new_ms(QEMU_CLOCK_REALTIME,
+ balloon_stop_free_page_report, s);
+}
+
static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq)
{
VirtIOBalloon *s = VIRTIO_BALLOON(vdev);
@@ -330,6 +389,7 @@ static void
virtio_balloon_poll_free_page_hints(VirtIOBalloon *dev)
if (id == dev->free_page_report_cmd_id) {
dev->free_page_report_status = FREE_PAGE_REPORT_S_START;
} else {
+ dev->host_stop_free_page = false;
dev->free_page_report_status = FREE_PAGE_REPORT_S_STOP;
break;
}
@@ -385,6 +445,10 @@ static void virtio_balloon_free_page_poll(void *opaque)
virtio_notify_config(vdev);
s->free_page_report_status = FREE_PAGE_REPORT_S_REQUESTED;
+ if (s->free_page_wait_time) {
+ balloon_free_page_change_timer(s, s->free_page_wait_time);
+ }
+
virtio_balloon_poll_free_page_hints(s);
}
@@ -395,7 +459,19 @@ static void virtio_balloon_get_config(VirtIODevice *vdev,
uint8_t *config_data)
config.num_pages = cpu_to_le32(dev->num_pages);
config.actual = cpu_to_le32(dev->actual);
- config.free_page_report_cmd_id = cpu_to_le32(dev->free_page_report_cmd_id);
+ if (dev->host_stop_free_page) {
+ /*
+ * Host is actively requesting to stop the free page reporting, send
+ * the stop sign to the guest. This happens when the migration thread
+ * has reached the phase to send pages to the destination while the
+ * guest hasn't done the reporting.
+ */
+ config.free_page_report_cmd_id =
+ VIRTIO_BALLOON_FREE_PAGE_REPORT_STOP_ID;
+ } else {
+ config.free_page_report_cmd_id =
+ cpu_to_le32(dev->free_page_report_cmd_id);
+ }
trace_virtio_balloon_get_config(config.num_pages, config.actual);
memcpy(config_data, &config, sizeof(struct virtio_balloon_config));
@@ -539,6 +615,7 @@ static void virtio_balloon_device_realize(DeviceState *dev,
Error **errp)
s->free_page_vq = virtio_add_queue(vdev, VIRTQUEUE_MAX_SIZE, NULL);
s->free_page_report_status = FREE_PAGE_REPORT_S_STOP;
s->free_page_report_cmd_id = VIRTIO_BALLOON_FREE_PAGE_REPORT_STOP_ID;
+ s->host_stop_free_page = false;
}
reset_stats(s);
}
@@ -602,6 +679,11 @@ static void virtio_balloon_instance_init(Object *obj)
balloon_stats_get_poll_interval,
balloon_stats_set_poll_interval,
NULL, s, NULL);
+
+ object_property_add(obj, "free-page-wait-time", "int",
+ balloon_free_page_get_wait_time,
+ balloon_free_page_set_wait_time,
+ NULL, s, NULL);
}
static const VMStateDescription vmstate_virtio_balloon = {
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index 6c75cca..3345104 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -2250,6 +2250,9 @@ static void virtio_balloon_pci_instance_init(Object *obj)
object_property_add_alias(obj, "guest-stats-polling-interval",
OBJECT(&dev->vdev),
"guest-stats-polling-interval", &error_abort);
+ object_property_add_alias(obj, "free-page-wait-time",
+ OBJECT(&dev->vdev),
+ "free-page-wait-time", &error_abort);
}
static const TypeInfo virtio_balloon_pci_info = {
diff --git a/include/hw/virtio/virtio-balloon.h
b/include/hw/virtio/virtio-balloon.h
index 11b4e01..c16855b 100644
--- a/include/hw/virtio/virtio-balloon.h
+++ b/include/hw/virtio/virtio-balloon.h
@@ -40,6 +40,8 @@ enum virtio_balloon_free_page_report_status {
typedef struct VirtIOBalloon {
VirtIODevice parent_obj;
VirtQueue *ivq, *dvq, *svq, *free_page_vq;
+ /* Host is requesting the guest to stop free page reporting */
+ bool host_stop_free_page;
uint32_t free_page_report_status;
uint32_t num_pages;
uint32_t actual;
@@ -49,8 +51,10 @@ typedef struct VirtIOBalloon {
VirtQueueElement *stats_vq_elem;
size_t stats_vq_offset;
QEMUTimer *stats_timer;
+ QEMUTimer *free_page_timer;
int64_t stats_last_update;
int64_t stats_poll_interval;
+ int64_t free_page_wait_time;
uint32_t host_features;
} VirtIOBalloon;
--
1.8.3.1
