Commit 943db62c316c ("powerpc/pseries: Revert 'Auto-online hotplugged memory'") reverted the auto-online feature for pseries due to problems with LMB removals not updating the device struct properly. Among other things, this commit made the following change in arch/powerpc/configs/pseries_defconfig:
@@ -58,7 +58,6 @@ CONFIG_KEXEC_FILE=y CONFIG_IRQ_ALL_CPUS=y CONFIG_MEMORY_HOTPLUG=y CONFIG_MEMORY_HOTREMOVE=y -CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE=y CONFIG_KSM=y The intent was to disable the option in the defconfig of pseries, since after that the code doesn't have this support anymore. However, this change alone isn't enough to prevent situations such as [1], where distros can enable the option unaware of the consequences of doing it (e.g. breaking LMB hotplug altogether). Instead of relying on all distros knowing that pseries can't handle CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE=y after 943db62c316c, this patch changes mm/Kconfig to make the MEMORY_HOTPLUG_DEFAULT_ONLINE config unavailable for the PPC64 arch. [1] https://bugzilla.redhat.com/show_bug.cgi?id=1476380 Fixes: 943db62c316c ("powerpc/pseries: Revert 'Auto-online hotplugged memory'") Signed-off-by: Daniel Henrique Barboza <danie...@linux.vnet.ibm.com> --- mm/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/Kconfig b/mm/Kconfig index 48b1af4..a342c77 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -169,7 +169,7 @@ config MEMORY_HOTPLUG_SPARSE config MEMORY_HOTPLUG_DEFAULT_ONLINE bool "Online the newly added memory blocks by default" default n - depends on MEMORY_HOTPLUG + depends on MEMORY_HOTPLUG && !PPC64 help This option sets the default policy setting for memory hotplug onlining policy (/sys/devices/system/memory/auto_online_blocks) which -- 2.9.4