From: Mike Rapoport <rppt@xxxxxxxxxxxxx> Subject: 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@xxxxxxxxxx Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxx> Acked-by: Arnd Bergmann <arnd@xxxxxxxx> Acked-by: David Hildenbrand <david@xxxxxxxxxx> Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> Cc: Ivan Kokshaysky <ink@xxxxxxxxxxxxxxxxxxxx> Cc: Jonathan Corbet <corbet@xxxxxxx> Cc: Matt Turner <mattst88@xxxxxxxxx> Cc: Richard Henderson <rth@xxxxxxxxxxx> Cc: Vineet Gupta <vgupta@xxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/asm-generic/memory_model.h | 37 ++------------------------- include/linux/mmzone.h | 8 +++-- mm/Kconfig | 25 ++---------------- mm/page_alloc.c | 13 --------- 4 files changed, 12 insertions(+), 71 deletions(-) --- a/include/asm-generic/memory_model.h~mm-remove-config_discontigmem +++ a/include/asm-generic/memory_model.h @@ -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 --- a/include/linux/mmzone.h~mm-remove-config_discontigmem +++ a/include/linux/mmzone.h @@ -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 { --- a/mm/Kconfig~mm-remove-config_discontigmem +++ a/mm/Kconfig @@ -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 --- a/mm/page_alloc.c~mm-remove-config_discontigmem +++ a/mm/page_alloc.c @@ -349,20 +349,7 @@ compound_page_dtor * const compound_page 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; _
