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authorPhilippe Mathieu-Daudé <philmd@redhat.com>2020-09-13 21:53:42 +0200
committerMarkus Armbruster <armbru@redhat.com>2020-09-29 15:41:35 +0200
commit81e248ce7b5752f21c641a619b8301dccc773c44 (patch)
tree04ca084ba3b497ca8897394b9c985b80ba1d5ddb /qapi
parent8dc007d3d9f79d0c60c750055a79ce8b21bfb494 (diff)
qapi: Correct balloon documentation
The documentation incorrectly uses the "size of the balloon" description when it should be "logical size of the VM". Fix it. The relation between both values is: logical_vm_size = vm_ram_size - balloon_size Reported-by: David Hildenbrand <david@redhat.com> Suggested-by: David Hildenbrand <david@redhat.com> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> Message-Id: <20200913195348.1064154-3-philmd@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>
Diffstat (limited to 'qapi')
-rw-r--r--qapi/misc.json13
1 files changed, 10 insertions, 3 deletions
diff --git a/qapi/misc.json b/qapi/misc.json
index b21963a176..a667fdf03e 100644
--- a/qapi/misc.json
+++ b/qapi/misc.json
@@ -192,7 +192,8 @@
#
# Information about the guest balloon device.
#
-# @actual: the number of bytes the balloon currently contains
+# @actual: the logical size of the VM in bytes
+# Formula used: logical_vm_size = vm_ram_size - balloon_size
#
# Since: 0.14.0
#
@@ -228,7 +229,8 @@
# Emitted when the guest changes the actual BALLOON level. This value is
# equivalent to the @actual field return by the 'query-balloon' command
#
-# @actual: actual level of the guest memory balloon in bytes
+# @actual: the logical size of the VM in bytes
+# Formula used: logical_vm_size = vm_ram_size - balloon_size
#
# Note: this event is rate-limited.
#
@@ -759,7 +761,10 @@
#
# Request the balloon driver to change its balloon size.
#
-# @value: the target size of the balloon in bytes
+# @value: the target logical size of the VM in bytes
+# We can deduce the size of the balloon using this formula:
+# logical_vm_size = vm_ram_size - balloon_size
+# From it we have: balloon_size = vm_ram_size - @value
#
# Returns: - Nothing on success
# - If the balloon driver is enabled but not functional because the KVM
@@ -777,6 +782,8 @@
# -> { "execute": "balloon", "arguments": { "value": 536870912 } }
# <- { "return": {} }
#
+# With a 2.5GiB guest this command inflated the balloon to 3GiB.
+#
##
{ 'command': 'balloon', 'data': {'value': 'int'} }