mm, memory_hotplug: drop CONFIG_MOVABLE_NODE

Commit 20b2f52b73fe ("numa: add CONFIG_MOVABLE_NODE for
movable-dedicated node") has introduced CONFIG_MOVABLE_NODE without a
good explanation on why it is actually useful.

It makes a lot of sense to make movable node semantic opt in but we
already have that because the feature has to be explicitly enabled on
the kernel command line.  A config option on top only makes the
configuration space larger without a good reason.  It also adds an
additional ifdefery that pollutes the code.

Just drop the config option and make it de-facto always enabled.  This
shouldn't introduce any change to the semantic.

Link: http://lkml.kernel.org/r/20170529114141.536-3-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Reza Arbab <arbab@linux.vnet.ibm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Yasuaki Ishimatsu <yasu.isimatu@gmail.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Kani Toshimitsu <toshi.kani@hpe.com>
Cc: Chen Yucong <slaoub@gmail.com>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Daniel Kiper <daniel.kiper@oracle.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 0 insertions, 26 deletions

diff --git a/mm/Kconfig b/mm/Kconfig
index 9870baafb096..857f6ef368d4 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -149,32 +149,6 @@ config NO_BOOTMEM
 config MEMORY_ISOLATION
         bool
 
-config MOVABLE_NODE
-        bool "Enable to assign a node which has only movable memory"
-        depends on HAVE_MEMBLOCK
-        depends on NO_BOOTMEM
-        depends on X86_64 || OF_EARLY_FLATTREE || MEMORY_HOTPLUG
-        depends on NUMA
-        default n
-        help
-          Allow a node to have only movable memory.  Pages used by the kernel,
-          such as direct mapping pages cannot be migrated.  So the corresponding
-          memory device cannot be hotplugged.  This option allows the following
-          two things:
-          - When the system is booting, node full of hotpluggable memory can
-          be arranged to have only movable memory so that the whole node can
-          be hot-removed. (need movable_node boot option specified).
-          - After the system is up, the option allows users to online all the
-          memory of a node as movable memory so that the whole node can be
-          hot-removed.
-
-          Users who don't use the memory hotplug feature are fine with this
-          option on since they don't specify movable_node boot option or they
-          don't online memory as movable.
-
-          Say Y here if you want to hotplug a whole node.
-          Say N here if you want kernel to use memory on all nodes evenly.
-
 #
 # Only be set on architectures that have completely implemented memory hotplug
 # feature. If you are not sure, don't touch it.