linux-5.10/mm/Kconfig

3 menu "Memory Management options"
10 	prompt "Memory model"
17 	  Linux manages its memory internally. Most users will
22 	bool "Flat Memory"
31 	  spaces and for features like NUMA and memory hotplug,
32 	  choose "Sparse Memory".
34 	  If unsure, choose this option (Flat Memory) over any other.
37 	bool "Discontiguous Memory"
41 	  memory systems, over FLATMEM.  These systems have holes
45 	  Although "Discontiguous Memory" is still used by several
47 	  "Sparse Memory".
49 	  If unsure, choose "Sparse Memory" over this option.
52 	bool "Sparse Memory"
56 	  memory hot-plug systems.  This is normal.
59 	  holes is their physical address space and allows memory
62 	  If unsure, choose "Flat Memory" over this option.
84 # to represent different areas of memory.  This variable allows
117 	bool "Sparse Memory virtual memmap"
132 # Don't discard allocated memory used to track "memory" and "reserved" memblocks
133 # after early boot, so it can still be used to test for validity of memory.
134 # Also, memblocks are updated with memory hot(un)plug.
146 # Only be set on architectures that have completely implemented memory hotplug
154 	bool "Allow for memory hot-add"
166 	bool "Online the newly added memory blocks by default"
169 	  This option sets the default policy setting for memory hotplug
170 	  onlining policy (/sys/devices/system/memory/auto_online_blocks) which
171 	  determines what happens to newly added memory regions. Policy setting
173 	  See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
175 	  Say Y here if you want all hot-plugged memory blocks to appear in
178 	  memory blocks in 'offline' state.
181 	bool "Allow for memory hot remove"
209 # support for memory balloon
214 # support for memory balloon compaction
216 	bool "Allow for balloon memory compaction/migration"
220 	  Memory fragmentation introduced by ballooning might reduce
221 	  significantly the number of 2MB contiguous memory blocks that can be
224 	  by the guest workload. Allowing the compaction & migration for memory
225 	  pages enlisted as being part of memory balloon devices avoids the
226 	  scenario aforementioned and helps improving memory defragmentation.
229 # support for memory compaction
231 	bool "Allow for memory compaction"
236 	  Compaction is the only memory management component to form
237 	  high order (larger physically contiguous) memory blocks
240 	  invocations for high order memory requests. You shouldn't
254 	  memory can be freed within the host for other uses.
289 	  the full range of memory available to the CPU. Enabled
315 	  saving memory until one or another app needs to modify the content.
326 	  This is the portion of low virtual memory which should be protected
346 	bool "Enable recovery from hardware memory errors"
350 	  Enables code to recover from some memory failures on systems
352 	  even when some of its memory has uncorrected errors. This requires
353 	  special hardware support and typically ECC memory.
366 	  of memory on which to store mappings, but it can only ask the system
397 	  applications by speeding up page faults during memory
401 	  If memory constrained on embedded, you may want to say N.
414 	  memory footprint of applications without a guaranteed
423 	  memory footprint of applications without a guaranteed
454 	  memory.  So when the PFRA "evicts" a page, it first attempts to use
456 	  "transcendent memory", memory that is not directly accessible or
462 	  When a transcendent memory driver is available (such as zcache or
463 	  Xen transcendent memory), a significant I/O reduction
476 	  "transcendent memory", memory that is not directly accessible or
478 	  time-varying size.  When space in transcendent memory is available,
487 	bool "Contiguous Memory Allocator"
492 	  This enables the Contiguous Memory Allocator which allows other
493 	  subsystems to allocate big physically-contiguous blocks of memory.
494 	  CMA reserves a region of memory and allows only movable pages to
495 	  be allocated from it. This way, the kernel can use the memory for
529 	bool "Track memory changes"
533 	  This option enables memory changes tracking by introducing a
547 	  compress them into a dynamically allocated RAM-based memory pool.
553 	  v3.11) that interacts heavily with memory reclaim.  While these
554 	  interactions don't cause any known issues on simple memory setups,
676 	tristate "Common API for compressed memory storage"
678 	  Compressed memory storage API.  This allows using either zbud or
700 	tristate "Memory allocator for compressed pages"
703 	  zsmalloc is a slab-based memory allocator designed to store
704 	  compressed RAM pages.  zsmalloc uses virtual memory mapping
731 	  arch). The stack will be located at the highest memory address minus
759 	  be useful to tune memory cgroup limits and/or for job placement
769 	bool "Device memory (pmem, HMM, etc...) hotplug support"
777 	  Device memory hotplug support allows for establishing pmem,
778 	  or other device driver discovered memory regions, in the
797 	bool "Unaddressable device memory (GPU memory, ...)"
803 	  memory; i.e., memory that is only accessible from the device (or
818 	bool "Collect percpu memory statistics"
822 	  be used to help understand percpu memory usage.