Commit bb1c50d3 authored by Mike Rapoport's avatar Mike Rapoport Committed by Linus Torvalds
Browse files

mm: remove CONFIG_DISCONTIGMEM 

There are no architectures that support DISCONTIGMEM left.

Remove the configuration option and the dead code it was guarding in the
generic memory management code.

Link: https://lkml.kernel.org/r/20210608091316.3622-6-rppt@kernel.org


Signed-off-by: default avatarMike Rapoport <rppt@linux.ibm.com>
Acked-by: default avatarArnd Bergmann <arnd@arndb.de>
Acked-by: default avatarDavid Hildenbrand <david@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 5ab06e10

include/asm-generic/memory_model.h

+4 −33
Original line number Diff line number Diff line
@@ -6,47 +6,18 @@ 


#ifndef __ASSEMBLY__



/*

 * supports 3 memory models.

 */

#if defined(CONFIG_FLATMEM)



#ifndef ARCH_PFN_OFFSET

#define ARCH_PFN_OFFSET		(0UL)

#endif



#elif defined(CONFIG_DISCONTIGMEM)



#ifndef arch_pfn_to_nid

#define arch_pfn_to_nid(pfn)	pfn_to_nid(pfn)

#endif



#ifndef arch_local_page_offset

#define arch_local_page_offset(pfn, nid)	\

	((pfn) - NODE_DATA(nid)->node_start_pfn)

#endif



#endif /* CONFIG_DISCONTIGMEM */



/*

 * supports 3 memory models.

 */

#if defined(CONFIG_FLATMEM)



#define __pfn_to_page(pfn)	(mem_map + ((pfn) - ARCH_PFN_OFFSET))

#define __page_to_pfn(page)	((unsigned long)((page) - mem_map) + \

				 ARCH_PFN_OFFSET)

#elif defined(CONFIG_DISCONTIGMEM)



#define __pfn_to_page(pfn)			\

({	unsigned long __pfn = (pfn);		\

	unsigned long __nid = arch_pfn_to_nid(__pfn);  \

	NODE_DATA(__nid)->node_mem_map + arch_local_page_offset(__pfn, __nid);\

})



#define __page_to_pfn(pg)						\

({	const struct page *__pg = (pg);					\

	struct pglist_data *__pgdat = NODE_DATA(page_to_nid(__pg));	\

	(unsigned long)(__pg - __pgdat->node_mem_map) +			\

	 __pgdat->node_start_pfn;					\

})



#elif defined(CONFIG_SPARSEMEM_VMEMMAP)
@@ -70,7 +41,7 @@ 
	struct mem_section *__sec = __pfn_to_section(__pfn);	\

	__section_mem_map_addr(__sec) + __pfn;		\

})

#endif /* CONFIG_FLATMEM/DISCONTIGMEM/SPARSEMEM */

#endif /* CONFIG_FLATMEM/SPARSEMEM */



/*

 * Convert a physical address to a Page Frame Number and back

include/linux/mmzone.h

+5 −3
Original line number Diff line number Diff line
@@ -749,10 +749,12 @@ struct zonelist { 
	struct zoneref _zonerefs[MAX_ZONES_PER_ZONELIST + 1];

};



#ifndef CONFIG_DISCONTIGMEM

/* The array of struct pages - for discontigmem use pgdat->lmem_map */

/*

 * The array of struct pages for flatmem.

 * It must be declared for SPARSEMEM as well because there are configurations

 * that rely on that.

 */

extern struct page *mem_map;

#endif



#ifdef CONFIG_TRANSPARENT_HUGEPAGE

struct deferred_split {

mm/Kconfig

+3 −22
Original line number Diff line number Diff line
@@ -19,7 +19,7 @@ choice 


config FLATMEM_MANUAL

	bool "Flat Memory"

	depends on !(ARCH_DISCONTIGMEM_ENABLE || ARCH_SPARSEMEM_ENABLE) || ARCH_FLATMEM_ENABLE

	depends on !ARCH_SPARSEMEM_ENABLE || ARCH_FLATMEM_ENABLE

	help

	  This option is best suited for non-NUMA systems with

	  flat address space. The FLATMEM is the most efficient
@@ -32,21 +32,6 @@ config FLATMEM_MANUAL 


	  If unsure, choose this option (Flat Memory) over any other.



config DISCONTIGMEM_MANUAL

	bool "Discontiguous Memory"

	depends on ARCH_DISCONTIGMEM_ENABLE

	help

	  This option provides enhanced support for discontiguous

	  memory systems, over FLATMEM.  These systems have holes

	  in their physical address spaces, and this option provides

	  more efficient handling of these holes.



	  Although "Discontiguous Memory" is still used by several

	  architectures, it is considered deprecated in favor of

	  "Sparse Memory".



	  If unsure, choose "Sparse Memory" over this option.



config SPARSEMEM_MANUAL

	bool "Sparse Memory"

	depends on ARCH_SPARSEMEM_ENABLE
@@ -62,17 +47,13 @@ config SPARSEMEM_MANUAL 


endchoice



config DISCONTIGMEM

	def_bool y

	depends on (!SELECT_MEMORY_MODEL && ARCH_DISCONTIGMEM_ENABLE) || DISCONTIGMEM_MANUAL



config SPARSEMEM

	def_bool y

	depends on (!SELECT_MEMORY_MODEL && ARCH_SPARSEMEM_ENABLE) || SPARSEMEM_MANUAL



config FLATMEM

	def_bool y

	depends on (!DISCONTIGMEM && !SPARSEMEM) || FLATMEM_MANUAL

	depends on !SPARSEMEM || FLATMEM_MANUAL



config FLAT_NODE_MEM_MAP

	def_bool y
@@ -85,7 +66,7 @@ config FLAT_NODE_MEM_MAP 
#

config NEED_MULTIPLE_NODES

	def_bool y

	depends on DISCONTIGMEM || NUMA

	depends on NUMA



#

# SPARSEMEM_EXTREME (which is the default) does some bootmem

mm/page_alloc.c

+0 −13
Original line number Diff line number Diff line
@@ -349,20 +349,7 @@ compound_page_dtor * const compound_page_dtors[NR_COMPOUND_DTORS] = { 


int min_free_kbytes = 1024;

int user_min_free_kbytes = -1;

#ifdef CONFIG_DISCONTIGMEM

/*

 * DiscontigMem defines memory ranges as separate pg_data_t even if the ranges

 * are not on separate NUMA nodes. Functionally this works but with

 * watermark_boost_factor, it can reclaim prematurely as the ranges can be

 * quite small. By default, do not boost watermarks on discontigmem as in

 * many cases very high-order allocations like THP are likely to be

 * unsupported and the premature reclaim offsets the advantage of long-term

 * fragmentation avoidance.

 */

int watermark_boost_factor __read_mostly;

#else

int watermark_boost_factor __read_mostly = 15000;

#endif

int watermark_scale_factor = 10;



static unsigned long nr_kernel_pages __initdata;