diff --git a/Documentation/memory-hotplug.txt b/Documentation/memory-hotplug.txt index 443f4b44ad97..0d7cb955aa01 100644 --- a/Documentation/memory-hotplug.txt +++ b/Documentation/memory-hotplug.txt @@ -261,10 +261,11 @@ it according to the policy which can be read from "auto_online_blocks" file: % cat /sys/devices/system/memory/auto_online_blocks -The default is "offline" which means the newly added memory is not in a -ready-to-use state and you have to "online" the newly added memory blocks -manually. Automatic onlining can be requested by writing "online" to -"auto_online_blocks" file: +The default depends on the CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE kernel config +option. If it is disabled the default is "offline" which means the newly added +memory is not in a ready-to-use state and you have to "online" the newly added +memory blocks manually. Automatic onlining can be requested by writing "online" +to "auto_online_blocks" file: % echo online > /sys/devices/system/memory/auto_online_blocks diff --git a/mm/Kconfig b/mm/Kconfig index d6e9042b99e0..b0432b71137d 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -192,6 +192,22 @@ config MEMORY_HOTPLUG_SPARSE def_bool y depends on SPARSEMEM && MEMORY_HOTPLUG +config MEMORY_HOTPLUG_DEFAULT_ONLINE + bool "Online the newly added memory blocks by default" + default n + depends on MEMORY_HOTPLUG + help + This option sets the default policy setting for memory hotplug + onlining policy (/sys/devices/system/memory/auto_online_blocks) which + determines what happens to newly added memory regions. Policy setting + can always be changed at runtime. + See Documentation/memory-hotplug.txt for more information. + + Say Y here if you want all hot-plugged memory blocks to appear in + 'online' state by default. + Say N here if you want the default policy to keep all hot-plugged + memory blocks in 'offline' state. + config MEMORY_HOTREMOVE bool "Allow for memory hot remove" select MEMORY_ISOLATION diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index b21d8895ea41..fcafbfcff044 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -78,7 +78,11 @@ static struct { #define memhp_lock_acquire() lock_map_acquire(&mem_hotplug.dep_map) #define memhp_lock_release() lock_map_release(&mem_hotplug.dep_map) +#ifndef CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE bool memhp_auto_online; +#else +bool memhp_auto_online = true; +#endif EXPORT_SYMBOL_GPL(memhp_auto_online); void get_online_mems(void)