47118af076
The MIGRATE_CMA migration type has two main characteristics: (i) only movable pages can be allocated from MIGRATE_CMA pageblocks and (ii) page allocator will never change migration type of MIGRATE_CMA pageblocks. This guarantees (to some degree) that page in a MIGRATE_CMA page block can always be migrated somewhere else (unless there's no memory left in the system). It is designed to be used for allocating big chunks (eg. 10MiB) of physically contiguous memory. Once driver requests contiguous memory, pages from MIGRATE_CMA pageblocks may be migrated away to create a contiguous block. To minimise number of migrations, MIGRATE_CMA migration type is the last type tried when page allocator falls back to other migration types when requested. Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Tested-by: Rob Clark <rob.clark@linaro.org> Tested-by: Ohad Ben-Cohen <ohad@wizery.com> Tested-by: Benjamin Gaignard <benjamin.gaignard@linaro.org> Tested-by: Robert Nelson <robertcnelson@gmail.com> Tested-by: Barry Song <Baohua.Song@csr.com>
382 lines
12 KiB
Plaintext
382 lines
12 KiB
Plaintext
config SELECT_MEMORY_MODEL
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def_bool y
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depends on EXPERIMENTAL || ARCH_SELECT_MEMORY_MODEL
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choice
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prompt "Memory model"
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depends on SELECT_MEMORY_MODEL
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default DISCONTIGMEM_MANUAL if ARCH_DISCONTIGMEM_DEFAULT
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default SPARSEMEM_MANUAL if ARCH_SPARSEMEM_DEFAULT
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default FLATMEM_MANUAL
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config FLATMEM_MANUAL
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bool "Flat Memory"
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depends on !(ARCH_DISCONTIGMEM_ENABLE || ARCH_SPARSEMEM_ENABLE) || ARCH_FLATMEM_ENABLE
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help
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This option allows you to change some of the ways that
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Linux manages its memory internally. Most users will
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only have one option here: FLATMEM. This is normal
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and a correct option.
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Some users of more advanced features like NUMA and
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memory hotplug may have different options here.
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DISCONTIGMEM is an more mature, better tested system,
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but is incompatible with memory hotplug and may suffer
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decreased performance over SPARSEMEM. If unsure between
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"Sparse Memory" and "Discontiguous Memory", choose
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"Discontiguous Memory".
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If unsure, choose this option (Flat Memory) over any other.
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config DISCONTIGMEM_MANUAL
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bool "Discontiguous Memory"
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depends on ARCH_DISCONTIGMEM_ENABLE
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help
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This option provides enhanced support for discontiguous
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memory systems, over FLATMEM. These systems have holes
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in their physical address spaces, and this option provides
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more efficient handling of these holes. However, the vast
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majority of hardware has quite flat address spaces, and
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can have degraded performance from the extra overhead that
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this option imposes.
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Many NUMA configurations will have this as the only option.
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If unsure, choose "Flat Memory" over this option.
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config SPARSEMEM_MANUAL
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bool "Sparse Memory"
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depends on ARCH_SPARSEMEM_ENABLE
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help
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This will be the only option for some systems, including
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memory hotplug systems. This is normal.
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For many other systems, this will be an alternative to
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"Discontiguous Memory". This option provides some potential
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performance benefits, along with decreased code complexity,
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but it is newer, and more experimental.
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If unsure, choose "Discontiguous Memory" or "Flat Memory"
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over this option.
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endchoice
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config DISCONTIGMEM
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def_bool y
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depends on (!SELECT_MEMORY_MODEL && ARCH_DISCONTIGMEM_ENABLE) || DISCONTIGMEM_MANUAL
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config SPARSEMEM
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def_bool y
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depends on (!SELECT_MEMORY_MODEL && ARCH_SPARSEMEM_ENABLE) || SPARSEMEM_MANUAL
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config FLATMEM
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def_bool y
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depends on (!DISCONTIGMEM && !SPARSEMEM) || FLATMEM_MANUAL
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config FLAT_NODE_MEM_MAP
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def_bool y
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depends on !SPARSEMEM
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#
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# Both the NUMA code and DISCONTIGMEM use arrays of pg_data_t's
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# to represent different areas of memory. This variable allows
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# those dependencies to exist individually.
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#
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config NEED_MULTIPLE_NODES
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def_bool y
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depends on DISCONTIGMEM || NUMA
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config HAVE_MEMORY_PRESENT
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def_bool y
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depends on ARCH_HAVE_MEMORY_PRESENT || SPARSEMEM
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#
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# SPARSEMEM_EXTREME (which is the default) does some bootmem
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# allocations when memory_present() is called. If this cannot
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# be done on your architecture, select this option. However,
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# statically allocating the mem_section[] array can potentially
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# consume vast quantities of .bss, so be careful.
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#
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# This option will also potentially produce smaller runtime code
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# with gcc 3.4 and later.
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#
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config SPARSEMEM_STATIC
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bool
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#
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# Architecture platforms which require a two level mem_section in SPARSEMEM
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# must select this option. This is usually for architecture platforms with
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# an extremely sparse physical address space.
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#
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config SPARSEMEM_EXTREME
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def_bool y
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depends on SPARSEMEM && !SPARSEMEM_STATIC
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config SPARSEMEM_VMEMMAP_ENABLE
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bool
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config SPARSEMEM_ALLOC_MEM_MAP_TOGETHER
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def_bool y
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depends on SPARSEMEM && X86_64
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config SPARSEMEM_VMEMMAP
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bool "Sparse Memory virtual memmap"
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depends on SPARSEMEM && SPARSEMEM_VMEMMAP_ENABLE
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default y
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help
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SPARSEMEM_VMEMMAP uses a virtually mapped memmap to optimise
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pfn_to_page and page_to_pfn operations. This is the most
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efficient option when sufficient kernel resources are available.
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config HAVE_MEMBLOCK
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boolean
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config HAVE_MEMBLOCK_NODE_MAP
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boolean
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config ARCH_DISCARD_MEMBLOCK
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boolean
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config NO_BOOTMEM
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boolean
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# eventually, we can have this option just 'select SPARSEMEM'
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config MEMORY_HOTPLUG
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bool "Allow for memory hot-add"
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depends on SPARSEMEM || X86_64_ACPI_NUMA
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depends on HOTPLUG && ARCH_ENABLE_MEMORY_HOTPLUG
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depends on (IA64 || X86 || PPC_BOOK3S_64 || SUPERH || S390)
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config MEMORY_HOTPLUG_SPARSE
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def_bool y
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depends on SPARSEMEM && MEMORY_HOTPLUG
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config MEMORY_HOTREMOVE
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bool "Allow for memory hot remove"
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depends on MEMORY_HOTPLUG && ARCH_ENABLE_MEMORY_HOTREMOVE
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depends on MIGRATION
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#
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# If we have space for more page flags then we can enable additional
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# optimizations and functionality.
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#
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# Regular Sparsemem takes page flag bits for the sectionid if it does not
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# use a virtual memmap. Disable extended page flags for 32 bit platforms
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# that require the use of a sectionid in the page flags.
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#
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config PAGEFLAGS_EXTENDED
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def_bool y
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depends on 64BIT || SPARSEMEM_VMEMMAP || !SPARSEMEM
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# Heavily threaded applications may benefit from splitting the mm-wide
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# page_table_lock, so that faults on different parts of the user address
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# space can be handled with less contention: split it at this NR_CPUS.
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# Default to 4 for wider testing, though 8 might be more appropriate.
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# ARM's adjust_pte (unused if VIPT) depends on mm-wide page_table_lock.
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# PA-RISC 7xxx's spinlock_t would enlarge struct page from 32 to 44 bytes.
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# DEBUG_SPINLOCK and DEBUG_LOCK_ALLOC spinlock_t also enlarge struct page.
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#
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config SPLIT_PTLOCK_CPUS
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int
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default "999999" if ARM && !CPU_CACHE_VIPT
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default "999999" if PARISC && !PA20
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default "999999" if DEBUG_SPINLOCK || DEBUG_LOCK_ALLOC
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default "4"
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#
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# support for memory compaction
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config COMPACTION
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bool "Allow for memory compaction"
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select MIGRATION
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depends on MMU
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help
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Allows the compaction of memory for the allocation of huge pages.
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#
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# support for page migration
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#
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config MIGRATION
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bool "Page migration"
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def_bool y
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depends on NUMA || ARCH_ENABLE_MEMORY_HOTREMOVE || COMPACTION || CMA
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help
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Allows the migration of the physical location of pages of processes
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while the virtual addresses are not changed. This is useful in
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two situations. The first is on NUMA systems to put pages nearer
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to the processors accessing. The second is when allocating huge
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pages as migration can relocate pages to satisfy a huge page
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allocation instead of reclaiming.
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config PHYS_ADDR_T_64BIT
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def_bool 64BIT || ARCH_PHYS_ADDR_T_64BIT
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config ZONE_DMA_FLAG
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int
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default "0" if !ZONE_DMA
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default "1"
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config BOUNCE
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def_bool y
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depends on BLOCK && MMU && (ZONE_DMA || HIGHMEM)
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config NR_QUICK
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int
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depends on QUICKLIST
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default "2" if AVR32
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default "1"
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config VIRT_TO_BUS
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def_bool y
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depends on !ARCH_NO_VIRT_TO_BUS
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config MMU_NOTIFIER
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bool
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config KSM
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bool "Enable KSM for page merging"
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depends on MMU
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help
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Enable Kernel Samepage Merging: KSM periodically scans those areas
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of an application's address space that an app has advised may be
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mergeable. When it finds pages of identical content, it replaces
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the many instances by a single page with that content, so
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saving memory until one or another app needs to modify the content.
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Recommended for use with KVM, or with other duplicative applications.
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See Documentation/vm/ksm.txt for more information: KSM is inactive
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until a program has madvised that an area is MADV_MERGEABLE, and
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root has set /sys/kernel/mm/ksm/run to 1 (if CONFIG_SYSFS is set).
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config DEFAULT_MMAP_MIN_ADDR
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int "Low address space to protect from user allocation"
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depends on MMU
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default 4096
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help
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This is the portion of low virtual memory which should be protected
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from userspace allocation. Keeping a user from writing to low pages
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can help reduce the impact of kernel NULL pointer bugs.
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For most ia64, ppc64 and x86 users with lots of address space
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a value of 65536 is reasonable and should cause no problems.
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On arm and other archs it should not be higher than 32768.
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Programs which use vm86 functionality or have some need to map
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this low address space will need CAP_SYS_RAWIO or disable this
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protection by setting the value to 0.
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This value can be changed after boot using the
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/proc/sys/vm/mmap_min_addr tunable.
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config ARCH_SUPPORTS_MEMORY_FAILURE
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bool
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config MEMORY_FAILURE
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depends on MMU
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depends on ARCH_SUPPORTS_MEMORY_FAILURE
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bool "Enable recovery from hardware memory errors"
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help
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Enables code to recover from some memory failures on systems
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with MCA recovery. This allows a system to continue running
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even when some of its memory has uncorrected errors. This requires
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special hardware support and typically ECC memory.
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config HWPOISON_INJECT
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tristate "HWPoison pages injector"
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depends on MEMORY_FAILURE && DEBUG_KERNEL && PROC_FS
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select PROC_PAGE_MONITOR
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config NOMMU_INITIAL_TRIM_EXCESS
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int "Turn on mmap() excess space trimming before booting"
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depends on !MMU
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default 1
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help
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The NOMMU mmap() frequently needs to allocate large contiguous chunks
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of memory on which to store mappings, but it can only ask the system
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allocator for chunks in 2^N*PAGE_SIZE amounts - which is frequently
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more than it requires. To deal with this, mmap() is able to trim off
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the excess and return it to the allocator.
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If trimming is enabled, the excess is trimmed off and returned to the
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system allocator, which can cause extra fragmentation, particularly
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if there are a lot of transient processes.
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If trimming is disabled, the excess is kept, but not used, which for
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long-term mappings means that the space is wasted.
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Trimming can be dynamically controlled through a sysctl option
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(/proc/sys/vm/nr_trim_pages) which specifies the minimum number of
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excess pages there must be before trimming should occur, or zero if
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no trimming is to occur.
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This option specifies the initial value of this option. The default
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of 1 says that all excess pages should be trimmed.
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See Documentation/nommu-mmap.txt for more information.
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config TRANSPARENT_HUGEPAGE
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bool "Transparent Hugepage Support"
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depends on X86 && MMU
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select COMPACTION
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help
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Transparent Hugepages allows the kernel to use huge pages and
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huge tlb transparently to the applications whenever possible.
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This feature can improve computing performance to certain
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applications by speeding up page faults during memory
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allocation, by reducing the number of tlb misses and by speeding
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up the pagetable walking.
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If memory constrained on embedded, you may want to say N.
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choice
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prompt "Transparent Hugepage Support sysfs defaults"
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depends on TRANSPARENT_HUGEPAGE
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default TRANSPARENT_HUGEPAGE_ALWAYS
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help
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Selects the sysfs defaults for Transparent Hugepage Support.
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config TRANSPARENT_HUGEPAGE_ALWAYS
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bool "always"
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help
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Enabling Transparent Hugepage always, can increase the
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memory footprint of applications without a guaranteed
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benefit but it will work automatically for all applications.
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config TRANSPARENT_HUGEPAGE_MADVISE
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bool "madvise"
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help
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Enabling Transparent Hugepage madvise, will only provide a
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performance improvement benefit to the applications using
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madvise(MADV_HUGEPAGE) but it won't risk to increase the
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memory footprint of applications without a guaranteed
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benefit.
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endchoice
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#
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# UP and nommu archs use km based percpu allocator
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#
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config NEED_PER_CPU_KM
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depends on !SMP
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bool
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default y
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config CLEANCACHE
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bool "Enable cleancache driver to cache clean pages if tmem is present"
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default n
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help
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Cleancache can be thought of as a page-granularity victim cache
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for clean pages that the kernel's pageframe replacement algorithm
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(PFRA) would like to keep around, but can't since there isn't enough
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memory. So when the PFRA "evicts" a page, it first attempts to use
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cleancache code to put the data contained in that page into
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"transcendent memory", memory that is not directly accessible or
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addressable by the kernel and is of unknown and possibly
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time-varying size. And when a cleancache-enabled
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filesystem wishes to access a page in a file on disk, it first
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checks cleancache to see if it already contains it; if it does,
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the page is copied into the kernel and a disk access is avoided.
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When a transcendent memory driver is available (such as zcache or
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Xen transcendent memory), a significant I/O reduction
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may be achieved. When none is available, all cleancache calls
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are reduced to a single pointer-compare-against-NULL resulting
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in a negligible performance hit.
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If unsure, say Y to enable cleancache
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