virtio: Add memory statistics reporting to the balloon driver
When using ballooning to manage overcommitted memory on a host, a system for
guests to communicate their memory usage to the host can provide information
that will minimize the impact of ballooning on the guests. The current method
employs a daemon running in each guest that communicates memory statistics to a
host daemon at a specified time interval. The host daemon aggregates this
information and inflates and/or deflates balloons according to the level of
host memory pressure. This approach is effective but overly complex since a
daemon must be installed inside each guest and coordinated to communicate with
the host. A simpler approach is to collect memory statistics in the virtio
balloon driver and communicate them directly to the hypervisor.
Signed-off-by: Adam Litke <agl@us.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
diff --git a/qemu-monitor.hx b/qemu-monitor.hx
index 415734a..b51bb47 100644
--- a/qemu-monitor.hx
+++ b/qemu-monitor.hx
@@ -891,7 +891,8 @@
.params = "target",
.help = "request VM to change it's memory allocation (in MB)",
.user_print = monitor_user_noop,
- .mhandler.cmd_new = do_balloon,
+ .mhandler.cmd_async = do_balloon,
+ .async = 1,
},
STEXI
