diff options
| -rw-r--r-- | drivers/xen/Kconfig | 23 | ||||
| -rw-r--r-- | drivers/xen/balloon.c | 11 |
2 files changed, 25 insertions, 9 deletions
diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig index 73708acce3ca..979a8317204f 100644 --- a/drivers/xen/Kconfig +++ b/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 --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c index e6058debd01b..7c8a2cf16f58 100644 --- a/drivers/xen/balloon.c +++ b/drivers/xen/balloon.c @@ -338,7 +338,16 @@ static enum bp_state reserve_additional_memory(void) } #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; |