The patch titled
Subject: xen_balloon: support memory auto onlining policy
has been added to the -mm tree. Its filename is
xen_balloon-support-memory-auto-onlining-policy.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/xen_balloon-support-memory-auto-onlining-policy.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/xen_balloon-support-memory-auto-onlining-policy.patch
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------------------------------------------------------
From: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
Subject: xen_balloon: support memory auto onlining policy
Add support for the newly added kernel memory auto onlining policy to Xen
ballon driver.
Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
Suggested-by: Daniel Kiper <daniel.kiper@xxxxxxxxxx>
Reviewed-by: Daniel Kiper <daniel.kiper@xxxxxxxxxx>
Acked-by: David Vrabel <david.vrabel@xxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Daniel Kiper <daniel.kiper@xxxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Tang Chen <tangchen@xxxxxxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: Xishi Qiu <qiuxishi@xxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: "K. Y. Srinivasan" <kys@xxxxxxxxxxxxx>
Cc: Igor Mammedov <imammedo@xxxxxxxxxx>
Cc: Kay Sievers <kay@xxxxxxxx>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/xen/Kconfig | 23 +++++++++++++++--------
drivers/xen/balloon.c | 11 ++++++++++-
2 files changed, 25 insertions(+), 9 deletions(-)
diff -puN drivers/xen/Kconfig~xen_balloon-support-memory-auto-onlining-policy drivers/xen/Kconfig
--- a/drivers/xen/Kconfig~xen_balloon-support-memory-auto-onlining-policy
+++ a/drivers/xen/Kconfig
@@ -37,23 +37,30 @@ config XEN_BALLOON_MEMORY_HOTPLUG
Memory could be hotplugged in following steps:
- 1) dom0: xl mem-max <domU> <maxmem>
+ 1) target domain: ensure that memory auto online policy is in
+ effect by checking /sys/devices/system/memory/auto_online_blocks
+ file (should be 'online').
+
+ 2) control domain: xl mem-max <target-domain> <maxmem>
where <maxmem> is >= requested memory size,
- 2) dom0: xl mem-set <domU> <memory>
+ 3) control domain: xl mem-set <target-domain> <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,
+ /sys/devices/system/xen_memory/xen_memory0/target_kb on the
+ target domain.
- 3) domU: for i in /sys/devices/system/memory/memory*/state; do \
- [ "`cat "$i"`" = offline ] && echo online > "$i"; done
+ Alternatively, if memory auto onlining was not requested at step 1
+ the newly added memory can be manually onlined in the target domain
+ by doing the following:
- Memory could be onlined automatically on domU by adding following line to udev rules:
+ for i in /sys/devices/system/memory/memory*/state; do \
+ [ "`cat "$i"`" = offline ] && echo online > "$i"; done
- SUBSYSTEM=="memory", ACTION=="add", RUN+="/bin/sh -c '[ -f /sys$devpath/state ] && echo online > /sys$devpath/state'"
+ or by adding the following line to udev rules:
- In that case step 3 should be omitted.
+ SUBSYSTEM=="memory", ACTION=="add", RUN+="/bin/sh -c '[ -f /sys$devpath/state ] && echo online > /sys$devpath/state'"
config XEN_BALLOON_MEMORY_HOTPLUG_LIMIT
int "Hotplugged memory limit (in GiB) for a PV guest"
diff -puN drivers/xen/balloon.c~xen_balloon-support-memory-auto-onlining-policy drivers/xen/balloon.c
--- a/drivers/xen/balloon.c~xen_balloon-support-memory-auto-onlining-policy
+++ a/drivers/xen/balloon.c
@@ -338,7 +338,16 @@ static enum bp_state reserve_additional_
}
#endif
- rc = add_memory_resource(nid, resource, false);
+ /*
+ * add_memory_resource() will call online_pages() which in its turn
+ * will call xen_online_page() callback causing deadlock if we don't
+ * release balloon_mutex here. Unlocking here is safe because the
+ * callers drop the mutex before trying again.
+ */
+ mutex_unlock(&balloon_mutex);
+ rc = add_memory_resource(nid, resource, memhp_auto_online);
+ mutex_lock(&balloon_mutex);
+
if (rc) {
pr_warn("Cannot add additional memory (%i)\n", rc);
goto err;
_
Patches currently in -mm which might be from vkuznets@xxxxxxxxxx are
lib-test-string_helpersc-fix-and-improve-string_get_size-tests.patch
memory-hotplug-add-automatic-onlining-policy-for-the-newly-added-memory.patch
xen_balloon-support-memory-auto-onlining-policy.patch
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