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>
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 34ae966..dd7abbe 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2303,8 +2303,11 @@
that the amount of memory usable for all allocations
is not too small.
- movable_node [KNL] Boot-time switch to enable the effects
- of CONFIG_MOVABLE_NODE=y. See mm/Kconfig for details.
+ movable_node [KNL] Boot-time switch to make hotplugable memory
+ NUMA nodes to be movable. This means that the memory
+ of such nodes will be usable only for movable
+ allocations which rules out almost all kernel
+ allocations. Use with caution!
MTD_Partition= [MTD]
Format: <name>,<region-number>,<size>,<offset>