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Commit f70029bb authored by Michal Hocko's avatar Michal Hocko Committed by Linus Torvalds
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mm, memory_hotplug: drop CONFIG_MOVABLE_NODE 

Commit 20b2f52b ("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: default avatarMichal Hocko <mhocko@suse.com>
Acked-by: default avatarReza Arbab <arbab@linux.vnet.ibm.com>
Acked-by: default avatarVlastimil 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 57c0a172

Documentation/admin-guide/kernel-parameters.txt

+5 −2
Original line number Diff line number Diff line
@@ -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>

drivers/base/node.c

+0 −4
Original line number Diff line number Diff line
@@ -639,9 +639,7 @@ static struct node_attr node_state_attr[] = { 
#ifdef CONFIG_HIGHMEM

	[N_HIGH_MEMORY] = _NODE_ATTR(has_high_memory, N_HIGH_MEMORY),

#endif

#ifdef CONFIG_MOVABLE_NODE

	[N_MEMORY] = _NODE_ATTR(has_memory, N_MEMORY),

#endif

	[N_CPU] = _NODE_ATTR(has_cpu, N_CPU),

};
@@ -652,9 +650,7 @@ static struct attribute *node_state_attrs[] = { 
#ifdef CONFIG_HIGHMEM

	&node_state_attr[N_HIGH_MEMORY].attr.attr,

#endif

#ifdef CONFIG_MOVABLE_NODE

	&node_state_attr[N_MEMORY].attr.attr,

#endif

	&node_state_attr[N_CPU].attr.attr,

	NULL

};

include/linux/memblock.h

+0 −18
Original line number Diff line number Diff line
@@ -57,10 +57,8 @@ struct memblock { 


extern struct memblock memblock;

extern int memblock_debug;

#ifdef CONFIG_MOVABLE_NODE

/* If movable_node boot option specified */

extern bool movable_node_enabled;

#endif /* CONFIG_MOVABLE_NODE */



#ifdef CONFIG_ARCH_DISCARD_MEMBLOCK

#define __init_memblock __meminit
@@ -169,7 +167,6 @@ void __next_reserved_mem_region(u64 *idx, phys_addr_t *out_start, 
	     i != (u64)ULLONG_MAX;					\

	     __next_reserved_mem_region(&i, p_start, p_end))



#ifdef CONFIG_MOVABLE_NODE

static inline bool memblock_is_hotpluggable(struct memblock_region *m)

{

	return m->flags & MEMBLOCK_HOTPLUG;
@@ -179,16 +176,6 @@ static inline bool __init_memblock movable_node_is_enabled(void) 
{

	return movable_node_enabled;

}

#else

static inline bool memblock_is_hotpluggable(struct memblock_region *m)

{

	return false;

}

static inline bool movable_node_is_enabled(void)

{

	return false;

}

#endif



static inline bool memblock_is_mirror(struct memblock_region *m)

{
@@ -296,7 +283,6 @@ phys_addr_t memblock_alloc_try_nid(phys_addr_t size, phys_addr_t align, int nid) 


phys_addr_t memblock_alloc(phys_addr_t size, phys_addr_t align);



#ifdef CONFIG_MOVABLE_NODE

/*

 * Set the allocation direction to bottom-up or top-down.

 */
@@ -314,10 +300,6 @@ static inline bool memblock_bottom_up(void) 
{

	return memblock.bottom_up;

}

#else

static inline void __init memblock_set_bottom_up(bool enable) {}

static inline bool memblock_bottom_up(void) { return false; }

#endif



/* Flags for memblock_alloc_base() amd __memblock_alloc_base() */

#define MEMBLOCK_ALLOC_ANYWHERE	(~(phys_addr_t)0)

include/linux/nodemask.h

+0 −4
Original line number Diff line number Diff line
@@ -387,11 +387,7 @@ enum node_states { 
#else

	N_HIGH_MEMORY = N_NORMAL_MEMORY,

#endif

#ifdef CONFIG_MOVABLE_NODE

	N_MEMORY,		/* The node has memory(regular, high, movable) */

#else

	N_MEMORY = N_HIGH_MEMORY,

#endif

	N_CPU,		/* The node has one or more cpus */

	NR_NODE_STATES

};

mm/Kconfig

+0 −26
Original line number Diff line number Diff line
@@ -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.