xen: document balloon driver sysfs files

Add ABI documentation for the balloon driver's sysfs files.

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Reviewed-by: Daniel Kiper <dkiper@net-space.pl>
[v2: Added comments from Daniel]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

diff --git a/Documentation/ABI/stable/sysfs-devices-system-xen_memory b/Documentation/ABI/stable/sysfs-devices-system-xen_memory
new file mode 100644 (file)
index 0000000..caa311d
--- /dev/null
+++ b/Documentation/ABI/stable/sysfs-devices-system-xen_memory
@@ -0,0 +1,77 @@
+What:          /sys/devices/system/xen_memory/xen_memory0/max_retry_count
+Date:          May 2011
+KernelVersion: 2.6.39
+Contact:       Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
+Description:
+               The maximum number of times the balloon driver will
+               attempt to increase the balloon before giving up.  See
+               also 'retry_count' below.
+               A value of zero means retry forever and is the default one.
+
+What:          /sys/devices/system/xen_memory/xen_memory0/max_schedule_delay
+Date:          May 2011
+KernelVersion: 2.6.39
+Contact:       Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
+Description:
+               The limit that 'schedule_delay' (see below) will be
+               increased to. The default value is 32 seconds.
+
+What:          /sys/devices/system/xen_memory/xen_memory0/retry_count
+Date:          May 2011
+KernelVersion: 2.6.39
+Contact:       Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
+Description:
+               The current number of times that the balloon driver
+               has attempted to increase the size of the balloon.
+               The default value is one. With max_retry_count being
+               zero (unlimited), this means that the driver will attempt
+               to retry with a 'schedule_delay' delay.
+
+What:          /sys/devices/system/xen_memory/xen_memory0/schedule_delay
+Date:          May 2011
+KernelVersion: 2.6.39
+Contact:       Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
+Description:
+               The time (in seconds) to wait between attempts to
+               increase the balloon.  Each time the balloon cannot be
+               increased, 'schedule_delay' is increased (until
+               'max_schedule_delay' is reached at which point it
+               will use the max value).
+
+What:          /sys/devices/system/xen_memory/xen_memory0/target
+Date:          April 2008
+KernelVersion: 2.6.26
+Contact:       Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
+Description:
+               The target number of pages to adjust this domain's
+               memory reservation to.
+
+What:          /sys/devices/system/xen_memory/xen_memory0/target_kb
+Date:          April 2008
+KernelVersion: 2.6.26
+Contact:       Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
+Description:
+               As target above, except the value is in KiB.
+
+What:          /sys/devices/system/xen_memory/xen_memory0/info/current_kb
+Date:          April 2008
+KernelVersion: 2.6.26
+Contact:       Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
+Description:
+               Current size (in KiB) of this domain's memory
+               reservation.
+
+What:          /sys/devices/system/xen_memory/xen_memory0/info/high_kb
+Date:          April 2008
+KernelVersion: 2.6.26
+Contact:       Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
+Description:
+               Amount (in KiB) of high memory in the balloon.
+
+What:          /sys/devices/system/xen_memory/xen_memory0/info/low_kb
+Date:          April 2008
+KernelVersion: 2.6.26
+Contact:       Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
+Description:
+               Amount (in KiB) of low (or normal) memory in the
+               balloon.