xen/balloon: memory hotplug support for Xen balloon driver
Memory hotplug support for Xen balloon driver. It should be mentioned
that hotplugged memory is not onlined automatically. It should be onlined
by user through standard sysfs interface.
Memory could be hotplugged in following steps:
1) dom0: xl mem-max <domU> <maxmem>
where <maxmem> is >= requested memory size,
2) dom0: xl mem-set <domU> <memory>
where <memory> is requested memory size; alternatively memory
could be added by writing proper value to
/sys/devices/system/xen_memory/xen_memory0/target or
/sys/devices/system/xen_memory/xen_memory0/target_kb on dumU,
3) domU: for i in /sys/devices/system/memory/memory*/state; do \
[ "`cat "$i"`" = offline ] && echo online > "$i"; done
Memory could be onlined automatically on domU by adding following line to
udev rules:
SUBSYSTEM=="memory", ACTION=="add", RUN+="/bin/sh -c '[ -f /sys$devpath/state ] && echo online > /sys$devpath/state'"
In that case step 3 should be omitted.
Signed-off-by: Daniel Kiper <dkiper@net-space.pl>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
index 03bc471..f815283 100644
--- a/drivers/xen/Kconfig
+++ b/drivers/xen/Kconfig
@@ -26,6 +26,36 @@
kernel boot parameter. Note that systems without a sufficiently
large swap device should not enable self-ballooning.
+config XEN_BALLOON_MEMORY_HOTPLUG
+ bool "Memory hotplug support for Xen balloon driver"
+ default n
+ depends on XEN_BALLOON && MEMORY_HOTPLUG
+ help
+ Memory hotplug support for Xen balloon driver allows expanding memory
+ available for the system above limit declared at system startup.
+ It is very useful on critical systems which require long
+ run without rebooting.
+
+ Memory could be hotplugged in following steps:
+
+ 1) dom0: xl mem-max <domU> <maxmem>
+ where <maxmem> is >= requested memory size,
+
+ 2) dom0: xl mem-set <domU> <memory>
+ where <memory> is requested memory size; alternatively memory
+ could be added by writing proper value to
+ /sys/devices/system/xen_memory/xen_memory0/target or
+ /sys/devices/system/xen_memory/xen_memory0/target_kb on dumU,
+
+ 3) domU: for i in /sys/devices/system/memory/memory*/state; do \
+ [ "`cat "$i"`" = offline ] && echo online > "$i"; done
+
+ Memory could be onlined automatically on domU by adding following line to udev rules:
+
+ SUBSYSTEM=="memory", ACTION=="add", RUN+="/bin/sh -c '[ -f /sys$devpath/state ] && echo online > /sys$devpath/state'"
+
+ In that case step 3 should be omitted.
+
config XEN_SCRUB_PAGES
bool "Scrub pages before returning them to system"
depends on XEN_BALLOON