1 # SPDX-License-Identifier: GPL-2.0-only 1 # SPDX-License-Identifier: GPL-2.0-only
2 2
3 menu "Memory Management options" 3 menu "Memory Management options"
4 4
5 # <<
6 # For some reason microblaze and nios2 hard co <<
7 # add proper SWAP support to them, in which ca <<
8 # <<
9 config ARCH_NO_SWAP <<
10 bool <<
11 <<
12 config ZPOOL <<
13 bool <<
14 <<
15 menuconfig SWAP <<
16 bool "Support for paging of anonymous <<
17 depends on MMU && BLOCK && !ARCH_NO_SW <<
18 default y <<
19 help <<
20 This option allows you to choose whe <<
21 for so called swap devices or swap f <<
22 used to provide more virtual memory <<
23 in your computer. If unsure say Y. <<
24 <<
25 config ZSWAP <<
26 bool "Compressed cache for swap pages" <<
27 depends on SWAP <<
28 select CRYPTO <<
29 select ZPOOL <<
30 help <<
31 A lightweight compressed cache for s <<
32 pages that are in the process of bei <<
33 compress them into a dynamically all <<
34 This can result in a significant I/O <<
35 in the case where decompressing from <<
36 reads, can also improve workload per <<
37 <<
38 config ZSWAP_DEFAULT_ON <<
39 bool "Enable the compressed cache for <<
40 depends on ZSWAP <<
41 help <<
42 If selected, the compressed cache fo <<
43 at boot, otherwise it will be disabl <<
44 <<
45 The selection made here can be overr <<
46 command line 'zswap.enabled=' option <<
47 <<
48 config ZSWAP_SHRINKER_DEFAULT_ON <<
49 bool "Shrink the zswap pool on memory <<
50 depends on ZSWAP <<
51 default n <<
52 help <<
53 If selected, the zswap shrinker will <<
54 stored in the zswap pool will become <<
55 written back to the backing swap dev <<
56 <<
57 This means that zswap writeback coul <<
58 not yet full, or the cgroup zswap li <<
59 reducing the chance that cold pages <<
60 and consume memory indefinitely. <<
61 <<
62 choice <<
63 prompt "Default compressor" <<
64 depends on ZSWAP <<
65 default ZSWAP_COMPRESSOR_DEFAULT_LZO <<
66 help <<
67 Selects the default compression algo <<
68 for swap pages. <<
69 <<
70 For an overview what kind of perform <<
71 a particular compression algorithm p <<
72 available at the following LWN page: <<
73 https://lwn.net/Articles/751795/ <<
74 <<
75 If in doubt, select 'LZO'. <<
76 <<
77 The selection made here can be overr <<
78 command line 'zswap.compressor=' opt <<
79 <<
80 config ZSWAP_COMPRESSOR_DEFAULT_DEFLATE <<
81 bool "Deflate" <<
82 select CRYPTO_DEFLATE <<
83 help <<
84 Use the Deflate algorithm as the def <<
85 <<
86 config ZSWAP_COMPRESSOR_DEFAULT_LZO <<
87 bool "LZO" <<
88 select CRYPTO_LZO <<
89 help <<
90 Use the LZO algorithm as the default <<
91 <<
92 config ZSWAP_COMPRESSOR_DEFAULT_842 <<
93 bool "842" <<
94 select CRYPTO_842 <<
95 help <<
96 Use the 842 algorithm as the default <<
97 <<
98 config ZSWAP_COMPRESSOR_DEFAULT_LZ4 <<
99 bool "LZ4" <<
100 select CRYPTO_LZ4 <<
101 help <<
102 Use the LZ4 algorithm as the default <<
103 <<
104 config ZSWAP_COMPRESSOR_DEFAULT_LZ4HC <<
105 bool "LZ4HC" <<
106 select CRYPTO_LZ4HC <<
107 help <<
108 Use the LZ4HC algorithm as the defau <<
109 <<
110 config ZSWAP_COMPRESSOR_DEFAULT_ZSTD <<
111 bool "zstd" <<
112 select CRYPTO_ZSTD <<
113 help <<
114 Use the zstd algorithm as the defaul <<
115 endchoice <<
116 <<
117 config ZSWAP_COMPRESSOR_DEFAULT <<
118 string <<
119 depends on ZSWAP <<
120 default "deflate" if ZSWAP_COMPRESSOR_D <<
121 default "lzo" if ZSWAP_COMPRESSOR_DEFAU <<
122 default "842" if ZSWAP_COMPRESSOR_DEFAU <<
123 default "lz4" if ZSWAP_COMPRESSOR_DEFAU <<
124 default "lz4hc" if ZSWAP_COMPRESSOR_DEF <<
125 default "zstd" if ZSWAP_COMPRESSOR_DEFA <<
126 default "" <<
127 <<
128 choice <<
129 prompt "Default allocator" <<
130 depends on ZSWAP <<
131 default ZSWAP_ZPOOL_DEFAULT_ZSMALLOC i <<
132 default ZSWAP_ZPOOL_DEFAULT_ZBUD <<
133 help <<
134 Selects the default allocator for th <<
135 swap pages. <<
136 The default is 'zbud' for compatibil <<
137 read the description of each of the <<
138 making a right choice. <<
139 <<
140 The selection made here can be overr <<
141 command line 'zswap.zpool=' option. <<
142 <<
143 config ZSWAP_ZPOOL_DEFAULT_ZBUD <<
144 bool "zbud" <<
145 select ZBUD <<
146 help <<
147 Use the zbud allocator as the defaul <<
148 <<
149 config ZSWAP_ZPOOL_DEFAULT_Z3FOLD_DEPRECATED <<
150 bool "z3foldi (DEPRECATED)" <<
151 select Z3FOLD_DEPRECATED <<
152 help <<
153 Use the z3fold allocator as the defa <<
154 <<
155 Deprecated and scheduled for removal <<
156 see CONFIG_Z3FOLD_DEPRECATED. <<
157 <<
158 config ZSWAP_ZPOOL_DEFAULT_ZSMALLOC <<
159 bool "zsmalloc" <<
160 select ZSMALLOC <<
161 help <<
162 Use the zsmalloc allocator as the de <<
163 endchoice <<
164 <<
165 config ZSWAP_ZPOOL_DEFAULT <<
166 string <<
167 depends on ZSWAP <<
168 default "zbud" if ZSWAP_ZPOOL_DEFAULT_Z <<
169 default "z3fold" if ZSWAP_ZPOOL_DEFAULT <<
170 default "zsmalloc" if ZSWAP_ZPOOL_DEFAU <<
171 default "" <<
172 <<
173 config ZBUD <<
174 tristate "2:1 compression allocator (z <<
175 depends on ZSWAP <<
176 help <<
177 A special purpose allocator for stor <<
178 It is designed to store up to two co <<
179 page. While this design limits stor <<
180 deterministic reclaim properties tha <<
181 density approach when reclaim will b <<
182 <<
183 config Z3FOLD_DEPRECATED <<
184 tristate "3:1 compression allocator (z <<
185 depends on ZSWAP <<
186 help <<
187 Deprecated and scheduled for removal <<
188 a good reason for using Z3FOLD over <<
189 linux-mm@kvack.org and the zswap mai <<
190 <<
191 A special purpose allocator for stor <<
192 It is designed to store up to three <<
193 page. It is a ZBUD derivative so the <<
194 still there. <<
195 <<
196 config Z3FOLD <<
197 tristate <<
198 default y if Z3FOLD_DEPRECATED=y <<
199 default m if Z3FOLD_DEPRECATED=m <<
200 depends on Z3FOLD_DEPRECATED <<
201 <<
202 config ZSMALLOC <<
203 tristate <<
204 prompt "N:1 compression allocator (zsm <<
205 depends on MMU <<
206 help <<
207 zsmalloc is a slab-based memory allo <<
208 pages of various compression levels <<
209 the highest storage density with the <<
210 <<
211 config ZSMALLOC_STAT <<
212 bool "Export zsmalloc statistics" <<
213 depends on ZSMALLOC <<
214 select DEBUG_FS <<
215 help <<
216 This option enables code in the zsma <<
217 statistics about what's happening in <<
218 information to userspace via debugfs <<
219 If unsure, say N. <<
220 <<
221 config ZSMALLOC_CHAIN_SIZE <<
222 int "Maximum number of physical pages <<
223 default 8 <<
224 range 4 16 <<
225 depends on ZSMALLOC <<
226 help <<
227 This option sets the upper limit on <<
228 that a zmalloc page (zspage) can con <<
229 chain size is calculated for each si <<
230 initialization of the pool. <<
231 <<
232 Changing this option can alter the c <<
233 such as the number of pages per zspa <<
234 per zspage. This can also result in <<
235 the pool, as zsmalloc merges size cl <<
236 characteristics. <<
237 <<
238 For more information, see zsmalloc d <<
239 <<
240 menu "Slab allocator options" <<
241 <<
242 config SLUB <<
243 def_bool y <<
244 <<
245 config SLUB_TINY <<
246 bool "Configure for minimal memory foo <<
247 depends on EXPERT <<
248 select SLAB_MERGE_DEFAULT <<
249 help <<
250 Configures the slab allocator in a <<
251 footprint, sacrificing scalability, <<
252 This is intended only for the small <<
253 SLOB allocator and is not recommend <<
254 16MB RAM. <<
255 <<
256 If unsure, say N. <<
257 <<
258 config SLAB_MERGE_DEFAULT <<
259 bool "Allow slab caches to be merged" <<
260 default y <<
261 help <<
262 For reduced kernel memory fragmentat <<
263 merged when they share the same size <<
264 This carries a risk of kernel heap o <<
265 overwrite objects from merged caches <<
266 cache layout), which makes such heap <<
267 by attackers. By keeping caches unme <<
268 can usually only damage objects in t <<
269 merging at runtime, "slab_nomerge" c <<
270 command line. <<
271 <<
272 config SLAB_FREELIST_RANDOM <<
273 bool "Randomize slab freelist" <<
274 depends on !SLUB_TINY <<
275 help <<
276 Randomizes the freelist order used o <<
277 security feature reduces the predict <<
278 allocator against heap overflows. <<
279 <<
280 config SLAB_FREELIST_HARDENED <<
281 bool "Harden slab freelist metadata" <<
282 depends on !SLUB_TINY <<
283 help <<
284 Many kernel heap attacks try to targ <<
285 other infrastructure. This options m <<
286 sacrifices to harden the kernel slab <<
287 freelist exploit methods. <<
288 <<
289 config SLAB_BUCKETS <<
290 bool "Support allocation from separate <<
291 depends on !SLUB_TINY <<
292 default SLAB_FREELIST_HARDENED <<
293 help <<
294 Kernel heap attacks frequently depen <<
295 specifically-sized allocations with <<
296 that will be allocated into the same <<
297 target object. To avoid sharing thes <<
298 provide an explicitly separated set <<
299 user-controlled allocations. This ma <<
300 memory fragmentation, though in prac <<
301 of extra pages since the bulk of use <<
302 are relatively long-lived. <<
303 <<
304 If unsure, say Y. <<
305 <<
306 config SLUB_STATS <<
307 default n <<
308 bool "Enable performance statistics" <<
309 depends on SYSFS && !SLUB_TINY <<
310 help <<
311 The statistics are useful to debug s <<
312 order find ways to optimize the allo <<
313 enabled for production use since kee <<
314 the allocator by a few percentage po <<
315 supports the determination of the mo <<
316 out which slabs are relevant to a pa <<
317 Try running: slabinfo -DA <<
318 <<
319 config SLUB_CPU_PARTIAL <<
320 default y <<
321 depends on SMP && !SLUB_TINY <<
322 bool "Enable per cpu partial caches" <<
323 help <<
324 Per cpu partial caches accelerate ob <<
325 that is local to a processor at the <<
326 in the latency of the free. On overf <<
327 which requires the taking of locks t <<
328 Typically one would choose no for a <<
329 <<
330 config RANDOM_KMALLOC_CACHES <<
331 default n <<
332 depends on !SLUB_TINY <<
333 bool "Randomize slab caches for normal <<
334 help <<
335 A hardening feature that creates mul <<
336 normal kmalloc allocation and makes <<
337 on code address, which makes the att <<
338 vulnerable memory objects on the hea <<
339 memory vulnerabilities. <<
340 <<
341 Currently the number of copies is se <<
342 that effectively diverges the memory <<
343 subsystems or modules into different <<
344 limited degree of memory and CPU ove <<
345 system workload. <<
346 <<
347 endmenu # Slab allocator options <<
348 <<
349 config SHUFFLE_PAGE_ALLOCATOR <<
350 bool "Page allocator randomization" <<
351 default SLAB_FREELIST_RANDOM && ACPI_N <<
352 help <<
353 Randomization of the page allocator <<
354 utilization of a direct-mapped memor <<
355 5.2.27 Heterogeneous Memory Attribut <<
356 6.2a specification for an example of <<
357 the presence of a memory-side-cache. <<
358 security benefits as it reduces the <<
359 allocations to compliment SLAB_FREEL <<
360 default granularity of shuffling on <<
361 order of pages is selected based on <<
362 on x86. <<
363 <<
364 While the randomization improves cac <<
365 negatively impact workloads on platf <<
366 this reason, by default, the randomi <<
367 if SHUFFLE_PAGE_ALLOCATOR=y. The ran <<
368 with the 'page_alloc.shuffle' kernel <<
369 <<
370 Say Y if unsure. <<
371 <<
372 config COMPAT_BRK <<
373 bool "Disable heap randomization" <<
374 default y <<
375 help <<
376 Randomizing heap placement makes hea <<
377 also breaks ancient binaries (includ <<
378 This option changes the bootup defau <<
379 disabled, and can be overridden at r <<
380 /proc/sys/kernel/randomize_va_space <<
381 <<
382 On non-ancient distros (post-2000 on <<
383 <<
384 config MMAP_ALLOW_UNINITIALIZED <<
385 bool "Allow mmapped anonymous memory t <<
386 depends on EXPERT && !MMU <<
387 default n <<
388 help <<
389 Normally, and according to the Linux <<
390 from mmap() has its contents cleared <<
391 userspace. Enabling this config opt <<
392 mmap() skip that if it is given an M <<
393 providing a huge performance boost. <<
394 then the flag will be ignored. <<
395 <<
396 This is taken advantage of by uClibc <<
397 ELF-FDPIC binfmt's brk and stack all <<
398 <<
399 Because of the obvious security issu <<
400 enabled on embedded devices where yo <<
401 userspace. Since that isn't general <<
402 it is normally safe to say Y here. <<
403 <<
404 See Documentation/admin-guide/mm/nom <<
405 <<
406 config SELECT_MEMORY_MODEL 5 config SELECT_MEMORY_MODEL
407 def_bool y 6 def_bool y
408 depends on ARCH_SELECT_MEMORY_MODEL 7 depends on ARCH_SELECT_MEMORY_MODEL
409 8
410 choice 9 choice
411 prompt "Memory model" 10 prompt "Memory model"
412 depends on SELECT_MEMORY_MODEL 11 depends on SELECT_MEMORY_MODEL
>> 12 default DISCONTIGMEM_MANUAL if ARCH_DISCONTIGMEM_DEFAULT
413 default SPARSEMEM_MANUAL if ARCH_SPARS 13 default SPARSEMEM_MANUAL if ARCH_SPARSEMEM_DEFAULT
414 default FLATMEM_MANUAL 14 default FLATMEM_MANUAL
415 help 15 help
416 This option allows you to change som 16 This option allows you to change some of the ways that
417 Linux manages its memory internally. 17 Linux manages its memory internally. Most users will
418 only have one option here selected b 18 only have one option here selected by the architecture
419 configuration. This is normal. 19 configuration. This is normal.
420 20
421 config FLATMEM_MANUAL 21 config FLATMEM_MANUAL
422 bool "Flat Memory" 22 bool "Flat Memory"
423 depends on !ARCH_SPARSEMEM_ENABLE || A !! 23 depends on !(ARCH_DISCONTIGMEM_ENABLE || ARCH_SPARSEMEM_ENABLE) || ARCH_FLATMEM_ENABLE
424 help 24 help
425 This option is best suited for non-N 25 This option is best suited for non-NUMA systems with
426 flat address space. The FLATMEM is t 26 flat address space. The FLATMEM is the most efficient
427 system in terms of performance and r 27 system in terms of performance and resource consumption
428 and it is the best option for smalle 28 and it is the best option for smaller systems.
429 29
430 For systems that have holes in their 30 For systems that have holes in their physical address
431 spaces and for features like NUMA an 31 spaces and for features like NUMA and memory hotplug,
432 choose "Sparse Memory". 32 choose "Sparse Memory".
433 33
434 If unsure, choose this option (Flat 34 If unsure, choose this option (Flat Memory) over any other.
435 35
>> 36 config DISCONTIGMEM_MANUAL
>> 37 bool "Discontiguous Memory"
>> 38 depends on ARCH_DISCONTIGMEM_ENABLE
>> 39 help
>> 40 This option provides enhanced support for discontiguous
>> 41 memory systems, over FLATMEM. These systems have holes
>> 42 in their physical address spaces, and this option provides
>> 43 more efficient handling of these holes.
>> 44
>> 45 Although "Discontiguous Memory" is still used by several
>> 46 architectures, it is considered deprecated in favor of
>> 47 "Sparse Memory".
>> 48
>> 49 If unsure, choose "Sparse Memory" over this option.
>> 50
436 config SPARSEMEM_MANUAL 51 config SPARSEMEM_MANUAL
437 bool "Sparse Memory" 52 bool "Sparse Memory"
438 depends on ARCH_SPARSEMEM_ENABLE 53 depends on ARCH_SPARSEMEM_ENABLE
439 help 54 help
440 This will be the only option for som 55 This will be the only option for some systems, including
441 memory hot-plug systems. This is no 56 memory hot-plug systems. This is normal.
442 57
443 This option provides efficient suppo 58 This option provides efficient support for systems with
444 holes is their physical address spac 59 holes is their physical address space and allows memory
445 hot-plug and hot-remove. 60 hot-plug and hot-remove.
446 61
447 If unsure, choose "Flat Memory" over 62 If unsure, choose "Flat Memory" over this option.
448 63
449 endchoice 64 endchoice
450 65
>> 66 config DISCONTIGMEM
>> 67 def_bool y
>> 68 depends on (!SELECT_MEMORY_MODEL && ARCH_DISCONTIGMEM_ENABLE) || DISCONTIGMEM_MANUAL
>> 69
451 config SPARSEMEM 70 config SPARSEMEM
452 def_bool y 71 def_bool y
453 depends on (!SELECT_MEMORY_MODEL && AR 72 depends on (!SELECT_MEMORY_MODEL && ARCH_SPARSEMEM_ENABLE) || SPARSEMEM_MANUAL
454 73
455 config FLATMEM 74 config FLATMEM
456 def_bool y 75 def_bool y
457 depends on !SPARSEMEM || FLATMEM_MANUA !! 76 depends on (!DISCONTIGMEM && !SPARSEMEM) || FLATMEM_MANUAL
>> 77
>> 78 config FLAT_NODE_MEM_MAP
>> 79 def_bool y
>> 80 depends on !SPARSEMEM
>> 81
>> 82 #
>> 83 # Both the NUMA code and DISCONTIGMEM use arrays of pg_data_t's
>> 84 # to represent different areas of memory. This variable allows
>> 85 # those dependencies to exist individually.
>> 86 #
>> 87 config NEED_MULTIPLE_NODES
>> 88 def_bool y
>> 89 depends on DISCONTIGMEM || NUMA
458 90
459 # 91 #
460 # SPARSEMEM_EXTREME (which is the default) doe 92 # SPARSEMEM_EXTREME (which is the default) does some bootmem
461 # allocations when sparse_init() is called. I 93 # allocations when sparse_init() is called. If this cannot
462 # be done on your architecture, select this op 94 # be done on your architecture, select this option. However,
463 # statically allocating the mem_section[] arra 95 # statically allocating the mem_section[] array can potentially
464 # consume vast quantities of .bss, so be caref 96 # consume vast quantities of .bss, so be careful.
465 # 97 #
466 # This option will also potentially produce sm 98 # This option will also potentially produce smaller runtime code
467 # with gcc 3.4 and later. 99 # with gcc 3.4 and later.
468 # 100 #
469 config SPARSEMEM_STATIC 101 config SPARSEMEM_STATIC
470 bool 102 bool
471 103
472 # 104 #
473 # Architecture platforms which require a two l 105 # Architecture platforms which require a two level mem_section in SPARSEMEM
474 # must select this option. This is usually for 106 # must select this option. This is usually for architecture platforms with
475 # an extremely sparse physical address space. 107 # an extremely sparse physical address space.
476 # 108 #
477 config SPARSEMEM_EXTREME 109 config SPARSEMEM_EXTREME
478 def_bool y 110 def_bool y
479 depends on SPARSEMEM && !SPARSEMEM_STA 111 depends on SPARSEMEM && !SPARSEMEM_STATIC
480 112
481 config SPARSEMEM_VMEMMAP_ENABLE 113 config SPARSEMEM_VMEMMAP_ENABLE
482 bool 114 bool
483 115
484 config SPARSEMEM_VMEMMAP 116 config SPARSEMEM_VMEMMAP
485 bool "Sparse Memory virtual memmap" 117 bool "Sparse Memory virtual memmap"
486 depends on SPARSEMEM && SPARSEMEM_VMEM 118 depends on SPARSEMEM && SPARSEMEM_VMEMMAP_ENABLE
487 default y 119 default y
488 help 120 help
489 SPARSEMEM_VMEMMAP uses a virtually m 121 SPARSEMEM_VMEMMAP uses a virtually mapped memmap to optimise
490 pfn_to_page and page_to_pfn operatio 122 pfn_to_page and page_to_pfn operations. This is the most
491 efficient option when sufficient ker 123 efficient option when sufficient kernel resources are available.
492 # <<
493 # Select this config option from the architect <<
494 # to enable the feature of HugeTLB/dev_dax vme <<
495 # <<
496 config ARCH_WANT_OPTIMIZE_DAX_VMEMMAP <<
497 bool <<
498 <<
499 config ARCH_WANT_OPTIMIZE_HUGETLB_VMEMMAP <<
500 bool <<
501 124
502 config HAVE_MEMBLOCK_PHYS_MAP 125 config HAVE_MEMBLOCK_PHYS_MAP
503 bool 126 bool
504 127
505 config HAVE_GUP_FAST !! 128 config HAVE_FAST_GUP
506 depends on MMU 129 depends on MMU
507 bool 130 bool
508 131
509 # Don't discard allocated memory used to track 132 # Don't discard allocated memory used to track "memory" and "reserved" memblocks
510 # after early boot, so it can still be used to 133 # after early boot, so it can still be used to test for validity of memory.
511 # Also, memblocks are updated with memory hot( 134 # Also, memblocks are updated with memory hot(un)plug.
512 config ARCH_KEEP_MEMBLOCK 135 config ARCH_KEEP_MEMBLOCK
513 bool 136 bool
514 137
515 # Keep arch NUMA mapping infrastructure post-i 138 # Keep arch NUMA mapping infrastructure post-init.
516 config NUMA_KEEP_MEMINFO 139 config NUMA_KEEP_MEMINFO
517 bool 140 bool
518 141
519 config MEMORY_ISOLATION 142 config MEMORY_ISOLATION
520 bool 143 bool
521 144
522 # IORESOURCE_SYSTEM_RAM regions in the kernel <<
523 # IORESOURCE_EXCLUSIVE cannot be mapped to use <<
524 # /dev/mem. <<
525 config EXCLUSIVE_SYSTEM_RAM <<
526 def_bool y <<
527 depends on !DEVMEM || STRICT_DEVMEM <<
528 <<
529 # 145 #
530 # Only be set on architectures that have compl 146 # Only be set on architectures that have completely implemented memory hotplug
531 # feature. If you are not sure, don't touch it 147 # feature. If you are not sure, don't touch it.
532 # 148 #
533 config HAVE_BOOTMEM_INFO_NODE 149 config HAVE_BOOTMEM_INFO_NODE
534 def_bool n 150 def_bool n
535 151
536 config ARCH_ENABLE_MEMORY_HOTPLUG <<
537 bool <<
538 <<
539 config ARCH_ENABLE_MEMORY_HOTREMOVE <<
540 bool <<
541 <<
542 # eventually, we can have this option just 'se 152 # eventually, we can have this option just 'select SPARSEMEM'
543 menuconfig MEMORY_HOTPLUG !! 153 config MEMORY_HOTPLUG
544 bool "Memory hotplug" !! 154 bool "Allow for memory hot-add"
545 select MEMORY_ISOLATION 155 select MEMORY_ISOLATION
546 depends on SPARSEMEM !! 156 depends on SPARSEMEM || X86_64_ACPI_NUMA
547 depends on ARCH_ENABLE_MEMORY_HOTPLUG 157 depends on ARCH_ENABLE_MEMORY_HOTPLUG
548 depends on 64BIT !! 158 depends on 64BIT || BROKEN
549 select NUMA_KEEP_MEMINFO if NUMA 159 select NUMA_KEEP_MEMINFO if NUMA
550 160
551 if MEMORY_HOTPLUG !! 161 config MEMORY_HOTPLUG_SPARSE
>> 162 def_bool y
>> 163 depends on SPARSEMEM && MEMORY_HOTPLUG
552 164
553 config MEMORY_HOTPLUG_DEFAULT_ONLINE 165 config MEMORY_HOTPLUG_DEFAULT_ONLINE
554 bool "Online the newly added memory bl 166 bool "Online the newly added memory blocks by default"
555 depends on MEMORY_HOTPLUG 167 depends on MEMORY_HOTPLUG
556 help 168 help
557 This option sets the default policy 169 This option sets the default policy setting for memory hotplug
558 onlining policy (/sys/devices/system 170 onlining policy (/sys/devices/system/memory/auto_online_blocks) which
559 determines what happens to newly add 171 determines what happens to newly added memory regions. Policy setting
560 can always be changed at runtime. 172 can always be changed at runtime.
561 See Documentation/admin-guide/mm/mem 173 See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
562 174
563 Say Y here if you want all hot-plugg 175 Say Y here if you want all hot-plugged memory blocks to appear in
564 'online' state by default. 176 'online' state by default.
565 Say N here if you want the default p 177 Say N here if you want the default policy to keep all hot-plugged
566 memory blocks in 'offline' state. 178 memory blocks in 'offline' state.
567 179
568 config MEMORY_HOTREMOVE 180 config MEMORY_HOTREMOVE
569 bool "Allow for memory hot remove" 181 bool "Allow for memory hot remove"
570 select HAVE_BOOTMEM_INFO_NODE if (X86_ 182 select HAVE_BOOTMEM_INFO_NODE if (X86_64 || PPC64)
571 depends on MEMORY_HOTPLUG && ARCH_ENAB 183 depends on MEMORY_HOTPLUG && ARCH_ENABLE_MEMORY_HOTREMOVE
572 depends on MIGRATION 184 depends on MIGRATION
573 185
574 config MHP_MEMMAP_ON_MEMORY <<
575 def_bool y <<
576 depends on MEMORY_HOTPLUG && SPARSEMEM <<
577 depends on ARCH_MHP_MEMMAP_ON_MEMORY_E <<
578 <<
579 endif # MEMORY_HOTPLUG <<
580 <<
581 config ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE <<
582 bool <<
583 <<
584 # Heavily threaded applications may benefit fr 186 # Heavily threaded applications may benefit from splitting the mm-wide
585 # page_table_lock, so that faults on different 187 # page_table_lock, so that faults on different parts of the user address
586 # space can be handled with less contention: s 188 # space can be handled with less contention: split it at this NR_CPUS.
587 # Default to 4 for wider testing, though 8 mig 189 # Default to 4 for wider testing, though 8 might be more appropriate.
588 # ARM's adjust_pte (unused if VIPT) depends on 190 # ARM's adjust_pte (unused if VIPT) depends on mm-wide page_table_lock.
589 # PA-RISC 7xxx's spinlock_t would enlarge stru 191 # PA-RISC 7xxx's spinlock_t would enlarge struct page from 32 to 44 bytes.
590 # SPARC32 allocates multiple pte tables within 192 # SPARC32 allocates multiple pte tables within a single page, and therefore
591 # a per-page lock leads to problems when multi 193 # a per-page lock leads to problems when multiple tables need to be locked
592 # at the same time (e.g. copy_page_range()). 194 # at the same time (e.g. copy_page_range()).
593 # DEBUG_SPINLOCK and DEBUG_LOCK_ALLOC spinlock 195 # DEBUG_SPINLOCK and DEBUG_LOCK_ALLOC spinlock_t also enlarge struct page.
594 # 196 #
595 config SPLIT_PTE_PTLOCKS !! 197 config SPLIT_PTLOCK_CPUS
596 def_bool y !! 198 int
597 depends on MMU !! 199 default "999999" if !MMU
598 depends on SMP !! 200 default "999999" if ARM && !CPU_CACHE_VIPT
599 depends on NR_CPUS >= 4 !! 201 default "999999" if PARISC && !PA20
600 depends on !ARM || CPU_CACHE_VIPT !! 202 default "999999" if SPARC32
601 depends on !PARISC || PA20 !! 203 default "4"
602 depends on !SPARC32 <<
603 204
604 config ARCH_ENABLE_SPLIT_PMD_PTLOCK 205 config ARCH_ENABLE_SPLIT_PMD_PTLOCK
605 bool 206 bool
606 207
607 config SPLIT_PMD_PTLOCKS <<
608 def_bool y <<
609 depends on SPLIT_PTE_PTLOCKS && ARCH_E <<
610 <<
611 # 208 #
612 # support for memory balloon 209 # support for memory balloon
613 config MEMORY_BALLOON 210 config MEMORY_BALLOON
614 bool 211 bool
615 212
616 # 213 #
617 # support for memory balloon compaction 214 # support for memory balloon compaction
618 config BALLOON_COMPACTION 215 config BALLOON_COMPACTION
619 bool "Allow for balloon memory compact 216 bool "Allow for balloon memory compaction/migration"
620 default y !! 217 def_bool y
621 depends on COMPACTION && MEMORY_BALLOO 218 depends on COMPACTION && MEMORY_BALLOON
622 help 219 help
623 Memory fragmentation introduced by b 220 Memory fragmentation introduced by ballooning might reduce
624 significantly the number of 2MB cont 221 significantly the number of 2MB contiguous memory blocks that can be
625 used within a guest, thus imposing p 222 used within a guest, thus imposing performance penalties associated
626 with the reduced number of transpare 223 with the reduced number of transparent huge pages that could be used
627 by the guest workload. Allowing the 224 by the guest workload. Allowing the compaction & migration for memory
628 pages enlisted as being part of memo 225 pages enlisted as being part of memory balloon devices avoids the
629 scenario aforementioned and helps im 226 scenario aforementioned and helps improving memory defragmentation.
630 227
631 # 228 #
632 # support for memory compaction 229 # support for memory compaction
633 config COMPACTION 230 config COMPACTION
634 bool "Allow for memory compaction" 231 bool "Allow for memory compaction"
635 default y !! 232 def_bool y
636 select MIGRATION 233 select MIGRATION
637 depends on MMU 234 depends on MMU
638 help 235 help
639 Compaction is the only memory manage 236 Compaction is the only memory management component to form
640 high order (larger physically contig 237 high order (larger physically contiguous) memory blocks
641 reliably. The page allocator relies 238 reliably. The page allocator relies on compaction heavily and
642 the lack of the feature can lead to 239 the lack of the feature can lead to unexpected OOM killer
643 invocations for high order memory re 240 invocations for high order memory requests. You shouldn't
644 disable this option unless there rea 241 disable this option unless there really is a strong reason for
645 it and then we would be really inter 242 it and then we would be really interested to hear about that at
646 linux-mm@kvack.org. 243 linux-mm@kvack.org.
647 244
648 config COMPACT_UNEVICTABLE_DEFAULT <<
649 int <<
650 depends on COMPACTION <<
651 default 0 if PREEMPT_RT <<
652 default 1 <<
653 <<
654 # 245 #
655 # support for free page reporting 246 # support for free page reporting
656 config PAGE_REPORTING 247 config PAGE_REPORTING
657 bool "Free page reporting" 248 bool "Free page reporting"
>> 249 def_bool n
658 help 250 help
659 Free page reporting allows for the i 251 Free page reporting allows for the incremental acquisition of
660 free pages from the buddy allocator 252 free pages from the buddy allocator for the purpose of reporting
661 those pages to another entity, such 253 those pages to another entity, such as a hypervisor, so that the
662 memory can be freed within the host 254 memory can be freed within the host for other uses.
663 255
664 # 256 #
665 # support for page migration 257 # support for page migration
666 # 258 #
667 config MIGRATION 259 config MIGRATION
668 bool "Page migration" 260 bool "Page migration"
669 default y !! 261 def_bool y
670 depends on (NUMA || ARCH_ENABLE_MEMORY 262 depends on (NUMA || ARCH_ENABLE_MEMORY_HOTREMOVE || COMPACTION || CMA) && MMU
671 help 263 help
672 Allows the migration of the physical 264 Allows the migration of the physical location of pages of processes
673 while the virtual addresses are not 265 while the virtual addresses are not changed. This is useful in
674 two situations. The first is on NUMA 266 two situations. The first is on NUMA systems to put pages nearer
675 to the processors accessing. The sec 267 to the processors accessing. The second is when allocating huge
676 pages as migration can relocate page 268 pages as migration can relocate pages to satisfy a huge page
677 allocation instead of reclaiming. 269 allocation instead of reclaiming.
678 270
679 config DEVICE_MIGRATION <<
680 def_bool MIGRATION && ZONE_DEVICE <<
681 <<
682 config ARCH_ENABLE_HUGEPAGE_MIGRATION 271 config ARCH_ENABLE_HUGEPAGE_MIGRATION
683 bool 272 bool
684 273
685 config ARCH_ENABLE_THP_MIGRATION 274 config ARCH_ENABLE_THP_MIGRATION
686 bool 275 bool
687 276
688 config HUGETLB_PAGE_SIZE_VARIABLE <<
689 def_bool n <<
690 help <<
691 Allows the pageblock_order value to <<
692 HUGETLB_PAGE_ORDER when there are mu <<
693 on a platform. <<
694 <<
695 Note that the pageblock_order cannot <<
696 clamped down to MAX_PAGE_ORDER. <<
697 <<
698 config CONTIG_ALLOC 277 config CONTIG_ALLOC
699 def_bool (MEMORY_ISOLATION && COMPACTI 278 def_bool (MEMORY_ISOLATION && COMPACTION) || CMA
700 279
701 config PCP_BATCH_SCALE_MAX <<
702 int "Maximum scale factor of PCP (Per- <<
703 default 5 <<
704 range 0 6 <<
705 help <<
706 In page allocator, PCP (Per-CPU page <<
707 batches. The batch number is scaled <<
708 allocation/free throughput. But too <<
709 latency. This option sets the upper <<
710 the maximum latency. <<
711 <<
712 config PHYS_ADDR_T_64BIT 280 config PHYS_ADDR_T_64BIT
713 def_bool 64BIT 281 def_bool 64BIT
714 282
715 config BOUNCE 283 config BOUNCE
716 bool "Enable bounce buffers" 284 bool "Enable bounce buffers"
717 default y 285 default y
718 depends on BLOCK && MMU && HIGHMEM !! 286 depends on BLOCK && MMU && (ZONE_DMA || HIGHMEM)
719 help 287 help
720 Enable bounce buffers for devices th !! 288 Enable bounce buffers for devices that cannot access
721 memory available to the CPU. Enabled !! 289 the full range of memory available to the CPU. Enabled
722 selected, but you may say n to overr !! 290 by default when ZONE_DMA or HIGHMEM is selected, but you
>> 291 may say n to override this.
>> 292
>> 293 config VIRT_TO_BUS
>> 294 bool
>> 295 help
>> 296 An architecture should select this if it implements the
>> 297 deprecated interface virt_to_bus(). All new architectures
>> 298 should probably not select this.
>> 299
723 300
724 config MMU_NOTIFIER 301 config MMU_NOTIFIER
725 bool 302 bool
>> 303 select SRCU
726 select INTERVAL_TREE 304 select INTERVAL_TREE
727 305
728 config KSM 306 config KSM
729 bool "Enable KSM for page merging" 307 bool "Enable KSM for page merging"
730 depends on MMU 308 depends on MMU
731 select XXHASH 309 select XXHASH
732 help 310 help
733 Enable Kernel Samepage Merging: KSM 311 Enable Kernel Samepage Merging: KSM periodically scans those areas
734 of an application's address space th 312 of an application's address space that an app has advised may be
735 mergeable. When it finds pages of i 313 mergeable. When it finds pages of identical content, it replaces
736 the many instances by a single page 314 the many instances by a single page with that content, so
737 saving memory until one or another a 315 saving memory until one or another app needs to modify the content.
738 Recommended for use with KVM, or wit 316 Recommended for use with KVM, or with other duplicative applications.
739 See Documentation/mm/ksm.rst for mor !! 317 See Documentation/vm/ksm.rst for more information: KSM is inactive
740 until a program has madvised that an 318 until a program has madvised that an area is MADV_MERGEABLE, and
741 root has set /sys/kernel/mm/ksm/run 319 root has set /sys/kernel/mm/ksm/run to 1 (if CONFIG_SYSFS is set).
742 320
743 config DEFAULT_MMAP_MIN_ADDR 321 config DEFAULT_MMAP_MIN_ADDR
744 int "Low address space to protect from 322 int "Low address space to protect from user allocation"
745 depends on MMU 323 depends on MMU
746 default 4096 324 default 4096
747 help 325 help
748 This is the portion of low virtual m 326 This is the portion of low virtual memory which should be protected
749 from userspace allocation. Keeping 327 from userspace allocation. Keeping a user from writing to low pages
750 can help reduce the impact of kernel 328 can help reduce the impact of kernel NULL pointer bugs.
751 329
752 For most arm64, ppc64 and x86 users !! 330 For most ia64, ppc64 and x86 users with lots of address space
753 a value of 65536 is reasonable and s 331 a value of 65536 is reasonable and should cause no problems.
754 On arm and other archs it should not 332 On arm and other archs it should not be higher than 32768.
755 Programs which use vm86 functionalit 333 Programs which use vm86 functionality or have some need to map
756 this low address space will need CAP 334 this low address space will need CAP_SYS_RAWIO or disable this
757 protection by setting the value to 0 335 protection by setting the value to 0.
758 336
759 This value can be changed after boot 337 This value can be changed after boot using the
760 /proc/sys/vm/mmap_min_addr tunable. 338 /proc/sys/vm/mmap_min_addr tunable.
761 339
762 config ARCH_SUPPORTS_MEMORY_FAILURE 340 config ARCH_SUPPORTS_MEMORY_FAILURE
763 bool 341 bool
764 342
765 config MEMORY_FAILURE 343 config MEMORY_FAILURE
766 depends on MMU 344 depends on MMU
767 depends on ARCH_SUPPORTS_MEMORY_FAILUR 345 depends on ARCH_SUPPORTS_MEMORY_FAILURE
768 bool "Enable recovery from hardware me 346 bool "Enable recovery from hardware memory errors"
769 select MEMORY_ISOLATION 347 select MEMORY_ISOLATION
770 select RAS 348 select RAS
771 help 349 help
772 Enables code to recover from some me 350 Enables code to recover from some memory failures on systems
773 with MCA recovery. This allows a sys 351 with MCA recovery. This allows a system to continue running
774 even when some of its memory has unc 352 even when some of its memory has uncorrected errors. This requires
775 special hardware support and typical 353 special hardware support and typically ECC memory.
776 354
777 config HWPOISON_INJECT 355 config HWPOISON_INJECT
778 tristate "HWPoison pages injector" 356 tristate "HWPoison pages injector"
779 depends on MEMORY_FAILURE && DEBUG_KER 357 depends on MEMORY_FAILURE && DEBUG_KERNEL && PROC_FS
780 select PROC_PAGE_MONITOR 358 select PROC_PAGE_MONITOR
781 359
782 config NOMMU_INITIAL_TRIM_EXCESS 360 config NOMMU_INITIAL_TRIM_EXCESS
783 int "Turn on mmap() excess space trimm 361 int "Turn on mmap() excess space trimming before booting"
784 depends on !MMU 362 depends on !MMU
785 default 1 363 default 1
786 help 364 help
787 The NOMMU mmap() frequently needs to 365 The NOMMU mmap() frequently needs to allocate large contiguous chunks
788 of memory on which to store mappings 366 of memory on which to store mappings, but it can only ask the system
789 allocator for chunks in 2^N*PAGE_SIZ 367 allocator for chunks in 2^N*PAGE_SIZE amounts - which is frequently
790 more than it requires. To deal with 368 more than it requires. To deal with this, mmap() is able to trim off
791 the excess and return it to the allo 369 the excess and return it to the allocator.
792 370
793 If trimming is enabled, the excess i 371 If trimming is enabled, the excess is trimmed off and returned to the
794 system allocator, which can cause ex 372 system allocator, which can cause extra fragmentation, particularly
795 if there are a lot of transient proc 373 if there are a lot of transient processes.
796 374
797 If trimming is disabled, the excess 375 If trimming is disabled, the excess is kept, but not used, which for
798 long-term mappings means that the sp 376 long-term mappings means that the space is wasted.
799 377
800 Trimming can be dynamically controll 378 Trimming can be dynamically controlled through a sysctl option
801 (/proc/sys/vm/nr_trim_pages) which s 379 (/proc/sys/vm/nr_trim_pages) which specifies the minimum number of
802 excess pages there must be before tr 380 excess pages there must be before trimming should occur, or zero if
803 no trimming is to occur. 381 no trimming is to occur.
804 382
805 This option specifies the initial va 383 This option specifies the initial value of this option. The default
806 of 1 says that all excess pages shou 384 of 1 says that all excess pages should be trimmed.
807 385
808 See Documentation/admin-guide/mm/nom 386 See Documentation/admin-guide/mm/nommu-mmap.rst for more information.
809 387
810 config ARCH_WANT_GENERAL_HUGETLB !! 388 config TRANSPARENT_HUGEPAGE
811 bool <<
812 <<
813 config ARCH_WANTS_THP_SWAP <<
814 def_bool n <<
815 <<
816 menuconfig TRANSPARENT_HUGEPAGE <<
817 bool "Transparent Hugepage Support" 389 bool "Transparent Hugepage Support"
818 depends on HAVE_ARCH_TRANSPARENT_HUGEP !! 390 depends on HAVE_ARCH_TRANSPARENT_HUGEPAGE
819 select COMPACTION 391 select COMPACTION
820 select XARRAY_MULTI 392 select XARRAY_MULTI
821 help 393 help
822 Transparent Hugepages allows the ker 394 Transparent Hugepages allows the kernel to use huge pages and
823 huge tlb transparently to the applic 395 huge tlb transparently to the applications whenever possible.
824 This feature can improve computing p 396 This feature can improve computing performance to certain
825 applications by speeding up page fau 397 applications by speeding up page faults during memory
826 allocation, by reducing the number o 398 allocation, by reducing the number of tlb misses and by speeding
827 up the pagetable walking. 399 up the pagetable walking.
828 400
829 If memory constrained on embedded, y 401 If memory constrained on embedded, you may want to say N.
830 402
831 if TRANSPARENT_HUGEPAGE <<
832 <<
833 choice 403 choice
834 prompt "Transparent Hugepage Support s 404 prompt "Transparent Hugepage Support sysfs defaults"
835 depends on TRANSPARENT_HUGEPAGE 405 depends on TRANSPARENT_HUGEPAGE
836 default TRANSPARENT_HUGEPAGE_ALWAYS 406 default TRANSPARENT_HUGEPAGE_ALWAYS
837 help 407 help
838 Selects the sysfs defaults for Trans 408 Selects the sysfs defaults for Transparent Hugepage Support.
839 409
840 config TRANSPARENT_HUGEPAGE_ALWAYS 410 config TRANSPARENT_HUGEPAGE_ALWAYS
841 bool "always" 411 bool "always"
842 help 412 help
843 Enabling Transparent Hugepage always 413 Enabling Transparent Hugepage always, can increase the
844 memory footprint of applications wit 414 memory footprint of applications without a guaranteed
845 benefit but it will work automatical 415 benefit but it will work automatically for all applications.
846 416
847 config TRANSPARENT_HUGEPAGE_MADVISE 417 config TRANSPARENT_HUGEPAGE_MADVISE
848 bool "madvise" 418 bool "madvise"
849 help 419 help
850 Enabling Transparent Hugepage madvis 420 Enabling Transparent Hugepage madvise, will only provide a
851 performance improvement benefit to t 421 performance improvement benefit to the applications using
852 madvise(MADV_HUGEPAGE) but it won't 422 madvise(MADV_HUGEPAGE) but it won't risk to increase the
853 memory footprint of applications wit 423 memory footprint of applications without a guaranteed
854 benefit. 424 benefit.
855 <<
856 config TRANSPARENT_HUGEPAGE_NEVER <<
857 bool "never" <<
858 help <<
859 Disable Transparent Hugepage by defa <<
860 enabled at runtime via sysfs. <<
861 endchoice 425 endchoice
862 426
>> 427 config ARCH_WANTS_THP_SWAP
>> 428 def_bool n
>> 429
863 config THP_SWAP 430 config THP_SWAP
864 def_bool y 431 def_bool y
865 depends on TRANSPARENT_HUGEPAGE && ARC !! 432 depends on TRANSPARENT_HUGEPAGE && ARCH_WANTS_THP_SWAP && SWAP
866 help 433 help
867 Swap transparent huge pages in one p 434 Swap transparent huge pages in one piece, without splitting.
868 XXX: For now, swap cluster backing t 435 XXX: For now, swap cluster backing transparent huge page
869 will be split after swapout. 436 will be split after swapout.
870 437
871 For selection by architectures with 438 For selection by architectures with reasonable THP sizes.
872 439
873 config READ_ONLY_THP_FOR_FS <<
874 bool "Read-only THP for filesystems (E <<
875 depends on TRANSPARENT_HUGEPAGE && SHM <<
876 <<
877 help <<
878 Allow khugepaged to put read-only fi <<
879 <<
880 This is marked experimental because <<
881 support of file THPs will be develop <<
882 cycles. <<
883 <<
884 endif # TRANSPARENT_HUGEPAGE <<
885 <<
886 # <<
887 # The architecture supports pgtable leaves tha <<
888 # <<
889 config PGTABLE_HAS_HUGE_LEAVES <<
890 def_bool TRANSPARENT_HUGEPAGE || HUGET <<
891 <<
892 # TODO: Allow to be enabled without THP <<
893 config ARCH_SUPPORTS_HUGE_PFNMAP <<
894 def_bool n <<
895 depends on TRANSPARENT_HUGEPAGE <<
896 <<
897 config ARCH_SUPPORTS_PMD_PFNMAP <<
898 def_bool y <<
899 depends on ARCH_SUPPORTS_HUGE_PFNMAP & <<
900 <<
901 config ARCH_SUPPORTS_PUD_PFNMAP <<
902 def_bool y <<
903 depends on ARCH_SUPPORTS_HUGE_PFNMAP & <<
904 <<
905 # 440 #
906 # UP and nommu archs use km based percpu alloc 441 # UP and nommu archs use km based percpu allocator
907 # 442 #
908 config NEED_PER_CPU_KM 443 config NEED_PER_CPU_KM
909 depends on !SMP || !MMU !! 444 depends on !SMP
910 bool 445 bool
911 default y 446 default y
912 447
913 config NEED_PER_CPU_EMBED_FIRST_CHUNK !! 448 config CLEANCACHE
914 bool !! 449 bool "Enable cleancache driver to cache clean pages if tmem is present"
>> 450 help
>> 451 Cleancache can be thought of as a page-granularity victim cache
>> 452 for clean pages that the kernel's pageframe replacement algorithm
>> 453 (PFRA) would like to keep around, but can't since there isn't enough
>> 454 memory. So when the PFRA "evicts" a page, it first attempts to use
>> 455 cleancache code to put the data contained in that page into
>> 456 "transcendent memory", memory that is not directly accessible or
>> 457 addressable by the kernel and is of unknown and possibly
>> 458 time-varying size. And when a cleancache-enabled
>> 459 filesystem wishes to access a page in a file on disk, it first
>> 460 checks cleancache to see if it already contains it; if it does,
>> 461 the page is copied into the kernel and a disk access is avoided.
>> 462 When a transcendent memory driver is available (such as zcache or
>> 463 Xen transcendent memory), a significant I/O reduction
>> 464 may be achieved. When none is available, all cleancache calls
>> 465 are reduced to a single pointer-compare-against-NULL resulting
>> 466 in a negligible performance hit.
915 467
916 config NEED_PER_CPU_PAGE_FIRST_CHUNK !! 468 If unsure, say Y to enable cleancache
917 bool <<
918 469
919 config USE_PERCPU_NUMA_NODE_ID !! 470 config FRONTSWAP
920 bool !! 471 bool "Enable frontswap to cache swap pages if tmem is present"
>> 472 depends on SWAP
>> 473 help
>> 474 Frontswap is so named because it can be thought of as the opposite
>> 475 of a "backing" store for a swap device. The data is stored into
>> 476 "transcendent memory", memory that is not directly accessible or
>> 477 addressable by the kernel and is of unknown and possibly
>> 478 time-varying size. When space in transcendent memory is available,
>> 479 a significant swap I/O reduction may be achieved. When none is
>> 480 available, all frontswap calls are reduced to a single pointer-
>> 481 compare-against-NULL resulting in a negligible performance hit
>> 482 and swap data is stored as normal on the matching swap device.
921 483
922 config HAVE_SETUP_PER_CPU_AREA !! 484 If unsure, say Y to enable frontswap.
923 bool <<
924 485
925 config CMA 486 config CMA
926 bool "Contiguous Memory Allocator" 487 bool "Contiguous Memory Allocator"
927 depends on MMU 488 depends on MMU
928 select MIGRATION 489 select MIGRATION
929 select MEMORY_ISOLATION 490 select MEMORY_ISOLATION
930 help 491 help
931 This enables the Contiguous Memory A 492 This enables the Contiguous Memory Allocator which allows other
932 subsystems to allocate big physicall 493 subsystems to allocate big physically-contiguous blocks of memory.
933 CMA reserves a region of memory and 494 CMA reserves a region of memory and allows only movable pages to
934 be allocated from it. This way, the 495 be allocated from it. This way, the kernel can use the memory for
935 pagecache and when a subsystem reque 496 pagecache and when a subsystem requests for contiguous area, the
936 allocated pages are migrated away to 497 allocated pages are migrated away to serve the contiguous request.
937 498
938 If unsure, say "n". 499 If unsure, say "n".
939 500
>> 501 config CMA_DEBUG
>> 502 bool "CMA debug messages (DEVELOPMENT)"
>> 503 depends on DEBUG_KERNEL && CMA
>> 504 help
>> 505 Turns on debug messages in CMA. This produces KERN_DEBUG
>> 506 messages for every CMA call as well as various messages while
>> 507 processing calls such as dma_alloc_from_contiguous().
>> 508 This option does not affect warning and error messages.
>> 509
940 config CMA_DEBUGFS 510 config CMA_DEBUGFS
941 bool "CMA debugfs interface" 511 bool "CMA debugfs interface"
942 depends on CMA && DEBUG_FS 512 depends on CMA && DEBUG_FS
943 help 513 help
944 Turns on the DebugFS interface for C 514 Turns on the DebugFS interface for CMA.
945 515
946 config CMA_SYSFS <<
947 bool "CMA information through sysfs in <<
948 depends on CMA && SYSFS <<
949 help <<
950 This option exposes some sysfs attri <<
951 from CMA. <<
952 <<
953 config CMA_AREAS 516 config CMA_AREAS
954 int "Maximum count of the CMA areas" 517 int "Maximum count of the CMA areas"
955 depends on CMA 518 depends on CMA
956 default 20 if NUMA !! 519 default 19 if NUMA
957 default 8 !! 520 default 7
958 help 521 help
959 CMA allows to create CMA areas for p 522 CMA allows to create CMA areas for particular purpose, mainly,
960 used as device private area. This pa 523 used as device private area. This parameter sets the maximum
961 number of CMA area in the system. 524 number of CMA area in the system.
962 525
963 If unsure, leave the default value " !! 526 If unsure, leave the default value "7" in UMA and "19" in NUMA.
964 527
965 config MEM_SOFT_DIRTY 528 config MEM_SOFT_DIRTY
966 bool "Track memory changes" 529 bool "Track memory changes"
967 depends on CHECKPOINT_RESTORE && HAVE_ 530 depends on CHECKPOINT_RESTORE && HAVE_ARCH_SOFT_DIRTY && PROC_FS
968 select PROC_PAGE_MONITOR 531 select PROC_PAGE_MONITOR
969 help 532 help
970 This option enables memory changes t 533 This option enables memory changes tracking by introducing a
971 soft-dirty bit on pte-s. This bit it 534 soft-dirty bit on pte-s. This bit it set when someone writes
972 into a page just as regular dirty bi 535 into a page just as regular dirty bit, but unlike the latter
973 it can be cleared by hands. 536 it can be cleared by hands.
974 537
975 See Documentation/admin-guide/mm/sof 538 See Documentation/admin-guide/mm/soft-dirty.rst for more details.
976 539
>> 540 config ZSWAP
>> 541 bool "Compressed cache for swap pages (EXPERIMENTAL)"
>> 542 depends on FRONTSWAP && CRYPTO=y
>> 543 select ZPOOL
>> 544 help
>> 545 A lightweight compressed cache for swap pages. It takes
>> 546 pages that are in the process of being swapped out and attempts to
>> 547 compress them into a dynamically allocated RAM-based memory pool.
>> 548 This can result in a significant I/O reduction on swap device and,
>> 549 in the case where decompressing from RAM is faster that swap device
>> 550 reads, can also improve workload performance.
>> 551
>> 552 This is marked experimental because it is a new feature (as of
>> 553 v3.11) that interacts heavily with memory reclaim. While these
>> 554 interactions don't cause any known issues on simple memory setups,
>> 555 they have not be fully explored on the large set of potential
>> 556 configurations and workloads that exist.
>> 557
>> 558 choice
>> 559 prompt "Compressed cache for swap pages default compressor"
>> 560 depends on ZSWAP
>> 561 default ZSWAP_COMPRESSOR_DEFAULT_LZO
>> 562 help
>> 563 Selects the default compression algorithm for the compressed cache
>> 564 for swap pages.
>> 565
>> 566 For an overview what kind of performance can be expected from
>> 567 a particular compression algorithm please refer to the benchmarks
>> 568 available at the following LWN page:
>> 569 https://lwn.net/Articles/751795/
>> 570
>> 571 If in doubt, select 'LZO'.
>> 572
>> 573 The selection made here can be overridden by using the kernel
>> 574 command line 'zswap.compressor=' option.
>> 575
>> 576 config ZSWAP_COMPRESSOR_DEFAULT_DEFLATE
>> 577 bool "Deflate"
>> 578 select CRYPTO_DEFLATE
>> 579 help
>> 580 Use the Deflate algorithm as the default compression algorithm.
>> 581
>> 582 config ZSWAP_COMPRESSOR_DEFAULT_LZO
>> 583 bool "LZO"
>> 584 select CRYPTO_LZO
>> 585 help
>> 586 Use the LZO algorithm as the default compression algorithm.
>> 587
>> 588 config ZSWAP_COMPRESSOR_DEFAULT_842
>> 589 bool "842"
>> 590 select CRYPTO_842
>> 591 help
>> 592 Use the 842 algorithm as the default compression algorithm.
>> 593
>> 594 config ZSWAP_COMPRESSOR_DEFAULT_LZ4
>> 595 bool "LZ4"
>> 596 select CRYPTO_LZ4
>> 597 help
>> 598 Use the LZ4 algorithm as the default compression algorithm.
>> 599
>> 600 config ZSWAP_COMPRESSOR_DEFAULT_LZ4HC
>> 601 bool "LZ4HC"
>> 602 select CRYPTO_LZ4HC
>> 603 help
>> 604 Use the LZ4HC algorithm as the default compression algorithm.
>> 605
>> 606 config ZSWAP_COMPRESSOR_DEFAULT_ZSTD
>> 607 bool "zstd"
>> 608 select CRYPTO_ZSTD
>> 609 help
>> 610 Use the zstd algorithm as the default compression algorithm.
>> 611 endchoice
>> 612
>> 613 config ZSWAP_COMPRESSOR_DEFAULT
>> 614 string
>> 615 depends on ZSWAP
>> 616 default "deflate" if ZSWAP_COMPRESSOR_DEFAULT_DEFLATE
>> 617 default "lzo" if ZSWAP_COMPRESSOR_DEFAULT_LZO
>> 618 default "842" if ZSWAP_COMPRESSOR_DEFAULT_842
>> 619 default "lz4" if ZSWAP_COMPRESSOR_DEFAULT_LZ4
>> 620 default "lz4hc" if ZSWAP_COMPRESSOR_DEFAULT_LZ4HC
>> 621 default "zstd" if ZSWAP_COMPRESSOR_DEFAULT_ZSTD
>> 622 default ""
>> 623
>> 624 choice
>> 625 prompt "Compressed cache for swap pages default allocator"
>> 626 depends on ZSWAP
>> 627 default ZSWAP_ZPOOL_DEFAULT_ZBUD
>> 628 help
>> 629 Selects the default allocator for the compressed cache for
>> 630 swap pages.
>> 631 The default is 'zbud' for compatibility, however please do
>> 632 read the description of each of the allocators below before
>> 633 making a right choice.
>> 634
>> 635 The selection made here can be overridden by using the kernel
>> 636 command line 'zswap.zpool=' option.
>> 637
>> 638 config ZSWAP_ZPOOL_DEFAULT_ZBUD
>> 639 bool "zbud"
>> 640 select ZBUD
>> 641 help
>> 642 Use the zbud allocator as the default allocator.
>> 643
>> 644 config ZSWAP_ZPOOL_DEFAULT_Z3FOLD
>> 645 bool "z3fold"
>> 646 select Z3FOLD
>> 647 help
>> 648 Use the z3fold allocator as the default allocator.
>> 649
>> 650 config ZSWAP_ZPOOL_DEFAULT_ZSMALLOC
>> 651 bool "zsmalloc"
>> 652 select ZSMALLOC
>> 653 help
>> 654 Use the zsmalloc allocator as the default allocator.
>> 655 endchoice
>> 656
>> 657 config ZSWAP_ZPOOL_DEFAULT
>> 658 string
>> 659 depends on ZSWAP
>> 660 default "zbud" if ZSWAP_ZPOOL_DEFAULT_ZBUD
>> 661 default "z3fold" if ZSWAP_ZPOOL_DEFAULT_Z3FOLD
>> 662 default "zsmalloc" if ZSWAP_ZPOOL_DEFAULT_ZSMALLOC
>> 663 default ""
>> 664
>> 665 config ZSWAP_DEFAULT_ON
>> 666 bool "Enable the compressed cache for swap pages by default"
>> 667 depends on ZSWAP
>> 668 help
>> 669 If selected, the compressed cache for swap pages will be enabled
>> 670 at boot, otherwise it will be disabled.
>> 671
>> 672 The selection made here can be overridden by using the kernel
>> 673 command line 'zswap.enabled=' option.
>> 674
>> 675 config ZPOOL
>> 676 tristate "Common API for compressed memory storage"
>> 677 help
>> 678 Compressed memory storage API. This allows using either zbud or
>> 679 zsmalloc.
>> 680
>> 681 config ZBUD
>> 682 tristate "Low (Up to 2x) density storage for compressed pages"
>> 683 help
>> 684 A special purpose allocator for storing compressed pages.
>> 685 It is designed to store up to two compressed pages per physical
>> 686 page. While this design limits storage density, it has simple and
>> 687 deterministic reclaim properties that make it preferable to a higher
>> 688 density approach when reclaim will be used.
>> 689
>> 690 config Z3FOLD
>> 691 tristate "Up to 3x density storage for compressed pages"
>> 692 depends on ZPOOL
>> 693 help
>> 694 A special purpose allocator for storing compressed pages.
>> 695 It is designed to store up to three compressed pages per physical
>> 696 page. It is a ZBUD derivative so the simplicity and determinism are
>> 697 still there.
>> 698
>> 699 config ZSMALLOC
>> 700 tristate "Memory allocator for compressed pages"
>> 701 depends on MMU
>> 702 help
>> 703 zsmalloc is a slab-based memory allocator designed to store
>> 704 compressed RAM pages. zsmalloc uses virtual memory mapping
>> 705 in order to reduce fragmentation. However, this results in a
>> 706 non-standard allocator interface where a handle, not a pointer, is
>> 707 returned by an alloc(). This handle must be mapped in order to
>> 708 access the allocated space.
>> 709
>> 710 config ZSMALLOC_STAT
>> 711 bool "Export zsmalloc statistics"
>> 712 depends on ZSMALLOC
>> 713 select DEBUG_FS
>> 714 help
>> 715 This option enables code in the zsmalloc to collect various
>> 716 statistics about whats happening in zsmalloc and exports that
>> 717 information to userspace via debugfs.
>> 718 If unsure, say N.
>> 719
977 config GENERIC_EARLY_IOREMAP 720 config GENERIC_EARLY_IOREMAP
978 bool 721 bool
979 722
980 config STACK_MAX_DEFAULT_SIZE_MB !! 723 config MAX_STACK_SIZE_MB
981 int "Default maximum user stack size f !! 724 int "Maximum user stack size for 32-bit processes (MB)"
982 default 100 !! 725 default 80
983 range 8 2048 726 range 8 2048
984 depends on STACK_GROWSUP && (!64BIT || 727 depends on STACK_GROWSUP && (!64BIT || COMPAT)
985 help 728 help
986 This is the maximum stack size in Me 729 This is the maximum stack size in Megabytes in the VM layout of 32-bit
987 user processes when the stack grows 730 user processes when the stack grows upwards (currently only on parisc
988 arch) when the RLIMIT_STACK hard lim !! 731 arch). The stack will be located at the highest memory address minus
>> 732 the given value, unless the RLIMIT_STACK hard limit is changed to a
>> 733 smaller value in which case that is used.
989 734
990 A sane initial value is 100 MB. !! 735 A sane initial value is 80 MB.
991 736
992 config DEFERRED_STRUCT_PAGE_INIT 737 config DEFERRED_STRUCT_PAGE_INIT
993 bool "Defer initialisation of struct p 738 bool "Defer initialisation of struct pages to kthreads"
994 depends on SPARSEMEM 739 depends on SPARSEMEM
995 depends on !NEED_PER_CPU_KM 740 depends on !NEED_PER_CPU_KM
996 depends on 64BIT 741 depends on 64BIT
997 depends on !KMSAN <<
998 select PADATA 742 select PADATA
999 help 743 help
1000 Ordinarily all struct pages are ini 744 Ordinarily all struct pages are initialised during early boot in a
1001 single thread. On very large machin 745 single thread. On very large machines this can take a considerable
1002 amount of time. If this option is s 746 amount of time. If this option is set, large machines will bring up
1003 a subset of memmap at boot and then 747 a subset of memmap at boot and then initialise the rest in parallel.
1004 This has a potential performance im 748 This has a potential performance impact on tasks running early in the
1005 lifetime of the system until these 749 lifetime of the system until these kthreads finish the
1006 initialisation. 750 initialisation.
1007 751
1008 config PAGE_IDLE_FLAG <<
1009 bool <<
1010 select PAGE_EXTENSION if !64BIT <<
1011 help <<
1012 This adds PG_idle and PG_young flag <<
1013 bit writers can set the state of th <<
1014 Accessed bit readers may avoid dist <<
1015 <<
1016 config IDLE_PAGE_TRACKING 752 config IDLE_PAGE_TRACKING
1017 bool "Enable idle page tracking" 753 bool "Enable idle page tracking"
1018 depends on SYSFS && MMU 754 depends on SYSFS && MMU
1019 select PAGE_IDLE_FLAG !! 755 select PAGE_EXTENSION if !64BIT
1020 help 756 help
1021 This feature allows to estimate the 757 This feature allows to estimate the amount of user pages that have
1022 not been touched during a given per 758 not been touched during a given period of time. This information can
1023 be useful to tune memory cgroup lim 759 be useful to tune memory cgroup limits and/or for job placement
1024 within a compute cluster. 760 within a compute cluster.
1025 761
1026 See Documentation/admin-guide/mm/id 762 See Documentation/admin-guide/mm/idle_page_tracking.rst for
1027 more details. 763 more details.
1028 764
1029 # Architectures which implement cpu_dcache_is <<
1030 # whether the data caches are aliased (VIVT o <<
1031 # aliasing) need to select this. <<
1032 config ARCH_HAS_CPU_CACHE_ALIASING <<
1033 bool <<
1034 <<
1035 config ARCH_HAS_CACHE_LINE_SIZE <<
1036 bool <<
1037 <<
1038 config ARCH_HAS_CURRENT_STACK_POINTER <<
1039 bool <<
1040 help <<
1041 In support of HARDENED_USERCOPY per <<
1042 checking, an architecture-agnostic <<
1043 is needed. Once an architecture def <<
1044 register alias named "current_stack <<
1045 selected. <<
1046 <<
1047 config ARCH_HAS_PTE_DEVMAP 765 config ARCH_HAS_PTE_DEVMAP
1048 bool 766 bool
1049 767
1050 config ARCH_HAS_ZONE_DMA_SET <<
1051 bool <<
1052 <<
1053 config ZONE_DMA <<
1054 bool "Support DMA zone" if ARCH_HAS_Z <<
1055 default y if ARM64 || X86 <<
1056 <<
1057 config ZONE_DMA32 <<
1058 bool "Support DMA32 zone" if ARCH_HAS <<
1059 depends on !X86_32 <<
1060 default y if ARM64 <<
1061 <<
1062 config ZONE_DEVICE 768 config ZONE_DEVICE
1063 bool "Device memory (pmem, HMM, etc.. 769 bool "Device memory (pmem, HMM, etc...) hotplug support"
1064 depends on MEMORY_HOTPLUG 770 depends on MEMORY_HOTPLUG
1065 depends on MEMORY_HOTREMOVE 771 depends on MEMORY_HOTREMOVE
1066 depends on SPARSEMEM_VMEMMAP 772 depends on SPARSEMEM_VMEMMAP
1067 depends on ARCH_HAS_PTE_DEVMAP 773 depends on ARCH_HAS_PTE_DEVMAP
1068 select XARRAY_MULTI 774 select XARRAY_MULTI
1069 775
1070 help 776 help
1071 Device memory hotplug support allow 777 Device memory hotplug support allows for establishing pmem,
1072 or other device driver discovered m 778 or other device driver discovered memory regions, in the
1073 memmap. This allows pfn_to_page() l 779 memmap. This allows pfn_to_page() lookups of otherwise
1074 "device-physical" addresses which i 780 "device-physical" addresses which is needed for using a DAX
1075 mapping in an O_DIRECT operation, a 781 mapping in an O_DIRECT operation, among other things.
1076 782
1077 If FS_DAX is enabled, then say Y. 783 If FS_DAX is enabled, then say Y.
1078 784
>> 785 config DEV_PAGEMAP_OPS
>> 786 bool
>> 787
1079 # 788 #
1080 # Helpers to mirror range of the CPU page tab 789 # Helpers to mirror range of the CPU page tables of a process into device page
1081 # tables. 790 # tables.
1082 # 791 #
1083 config HMM_MIRROR 792 config HMM_MIRROR
1084 bool 793 bool
1085 depends on MMU 794 depends on MMU
1086 795
1087 config GET_FREE_REGION <<
1088 bool <<
1089 <<
1090 config DEVICE_PRIVATE 796 config DEVICE_PRIVATE
1091 bool "Unaddressable device memory (GP 797 bool "Unaddressable device memory (GPU memory, ...)"
1092 depends on ZONE_DEVICE 798 depends on ZONE_DEVICE
1093 select GET_FREE_REGION !! 799 select DEV_PAGEMAP_OPS
1094 800
1095 help 801 help
1096 Allows creation of struct pages to 802 Allows creation of struct pages to represent unaddressable device
1097 memory; i.e., memory that is only a 803 memory; i.e., memory that is only accessible from the device (or
1098 group of devices). You likely also 804 group of devices). You likely also want to select HMM_MIRROR.
1099 805
1100 config VMAP_PFN 806 config VMAP_PFN
1101 bool 807 bool
1102 808
1103 config ARCH_USES_HIGH_VMA_FLAGS !! 809 config FRAME_VECTOR
1104 bool <<
1105 config ARCH_HAS_PKEYS <<
1106 bool 810 bool
1107 811
1108 config ARCH_USES_PG_ARCH_2 !! 812 config ARCH_USES_HIGH_VMA_FLAGS
1109 bool 813 bool
1110 config ARCH_USES_PG_ARCH_3 !! 814 config ARCH_HAS_PKEYS
1111 bool 815 bool
1112 816
1113 config VM_EVENT_COUNTERS <<
1114 default y <<
1115 bool "Enable VM event counters for /p <<
1116 help <<
1117 VM event counters are needed for ev <<
1118 This option allows the disabling of <<
1119 on EXPERT systems. /proc/vmstat wi <<
1120 if VM event counters are disabled. <<
1121 <<
1122 config PERCPU_STATS 817 config PERCPU_STATS
1123 bool "Collect percpu memory statistic 818 bool "Collect percpu memory statistics"
1124 help 819 help
1125 This feature collects and exposes s 820 This feature collects and exposes statistics via debugfs. The
1126 information includes global and per 821 information includes global and per chunk statistics, which can
1127 be used to help understand percpu m 822 be used to help understand percpu memory usage.
1128 823
1129 config GUP_TEST !! 824 config GUP_BENCHMARK
1130 bool "Enable infrastructure for get_u !! 825 bool "Enable infrastructure for get_user_pages() and related calls benchmarking"
1131 depends on DEBUG_FS <<
1132 help 826 help
1133 Provides /sys/kernel/debug/gup_test !! 827 Provides /sys/kernel/debug/gup_benchmark that helps with testing
1134 to make ioctl calls that can launch !! 828 performance of get_user_pages() and related calls.
1135 the get_user_pages*() and pin_user_ <<
1136 <<
1137 These tests include benchmark testi <<
1138 get_user_pages*() and pin_user_page <<
1139 the non-_fast variants. <<
1140 829
1141 There is also a sub-test that allow !! 830 See tools/testing/selftests/vm/gup_benchmark.c
1142 of up to eight pages (selected by c <<
1143 range of user-space addresses. Thes <<
1144 pin_user_pages*(), or pinned via ge <<
1145 by other command line arguments. <<
1146 831
1147 See tools/testing/selftests/mm/gup_ !! 832 config GUP_GET_PTE_LOW_HIGH
1148 <<
1149 comment "GUP_TEST needs to have DEBUG_FS enab <<
1150 depends on !GUP_TEST && !DEBUG_FS <<
1151 <<
1152 config GUP_GET_PXX_LOW_HIGH <<
1153 bool 833 bool
1154 834
1155 config DMAPOOL_TEST !! 835 config READ_ONLY_THP_FOR_FS
1156 tristate "Enable a module to run time !! 836 bool "Read-only THP for filesystems (EXPERIMENTAL)"
1157 depends on HAS_DMA !! 837 depends on TRANSPARENT_HUGEPAGE && SHMEM
1158 help <<
1159 Provides a test module that will al <<
1160 various sizes and report how long i <<
1161 provide a consistent way to measure <<
1162 dma_pool_alloc/free routines affect <<
1163 <<
1164 config ARCH_HAS_PTE_SPECIAL <<
1165 bool <<
1166 <<
1167 config MAPPING_DIRTY_HELPERS <<
1168 bool <<
1169 <<
1170 config KMAP_LOCAL <<
1171 bool <<
1172 <<
1173 config KMAP_LOCAL_NON_LINEAR_PTE_ARRAY <<
1174 bool <<
1175 <<
1176 # struct io_mapping based helper. Selected b <<
1177 config IO_MAPPING <<
1178 bool <<
1179 <<
1180 config MEMFD_CREATE <<
1181 bool "Enable memfd_create() system ca <<
1182 <<
1183 config SECRETMEM <<
1184 default y <<
1185 bool "Enable memfd_secret() system ca <<
1186 depends on ARCH_HAS_SET_DIRECT_MAP <<
1187 help <<
1188 Enable the memfd_secret() system ca <<
1189 memory areas visible only in the co <<
1190 not mapped to other processes and o <<
1191 <<
1192 config ANON_VMA_NAME <<
1193 bool "Anonymous VMA name support" <<
1194 depends on PROC_FS && ADVISE_SYSCALLS <<
1195 <<
1196 help <<
1197 Allow naming anonymous virtual memo <<
1198 <<
1199 This feature allows assigning names <<
1200 names can be later retrieved from / <<
1201 and help identifying individual ano <<
1202 Assigning a name to anonymous virtu <<
1203 area from being merged with adjacen <<
1204 difference in their name. <<
1205 <<
1206 config HAVE_ARCH_USERFAULTFD_WP <<
1207 bool <<
1208 help <<
1209 Arch has userfaultfd write protecti <<
1210 <<
1211 config HAVE_ARCH_USERFAULTFD_MINOR <<
1212 bool <<
1213 help <<
1214 Arch has userfaultfd minor fault su <<
1215 <<
1216 menuconfig USERFAULTFD <<
1217 bool "Enable userfaultfd() system cal <<
1218 depends on MMU <<
1219 help <<
1220 Enable the userfaultfd() system cal <<
1221 handle page faults in userland. <<
1222 <<
1223 if USERFAULTFD <<
1224 config PTE_MARKER_UFFD_WP <<
1225 bool "Userfaultfd write protection su <<
1226 default y <<
1227 depends on HAVE_ARCH_USERFAULTFD_WP <<
1228 <<
1229 help <<
1230 Allows to create marker PTEs for us <<
1231 purposes. It is required to enable <<
1232 file-backed memory types like shmem <<
1233 endif # USERFAULTFD <<
1234 <<
1235 # multi-gen LRU { <<
1236 config LRU_GEN <<
1237 bool "Multi-Gen LRU" <<
1238 depends on MMU <<
1239 # make sure folio->flags has enough s <<
1240 depends on 64BIT || !SPARSEMEM || SPA <<
1241 help <<
1242 A high performance LRU implementati <<
1243 Documentation/admin-guide/mm/multig <<
1244 <<
1245 config LRU_GEN_ENABLED <<
1246 bool "Enable by default" <<
1247 depends on LRU_GEN <<
1248 help <<
1249 This option enables the multi-gen L <<
1250 838
1251 config LRU_GEN_STATS <<
1252 bool "Full stats for debugging" <<
1253 depends on LRU_GEN <<
1254 help 839 help
1255 Do not enable this option unless yo !! 840 Allow khugepaged to put read-only file-backed pages in THP.
1256 from evicted generations for debugg <<
1257 <<
1258 This option has a per-memcg and per <<
1259 <<
1260 config LRU_GEN_WALKS_MMU <<
1261 def_bool y <<
1262 depends on LRU_GEN && ARCH_HAS_HW_PTE <<
1263 # } <<
1264 <<
1265 config ARCH_SUPPORTS_PER_VMA_LOCK <<
1266 def_bool n <<
1267 <<
1268 config PER_VMA_LOCK <<
1269 def_bool y <<
1270 depends on ARCH_SUPPORTS_PER_VMA_LOCK <<
1271 help <<
1272 Allow per-vma locking during page f <<
1273 <<
1274 This feature allows locking each vi <<
1275 handling page faults instead of tak <<
1276 <<
1277 config LOCK_MM_AND_FIND_VMA <<
1278 bool <<
1279 depends on !STACK_GROWSUP <<
1280 841
1281 config IOMMU_MM_DATA !! 842 This is marked experimental because it is a new feature. Write
1282 bool !! 843 support of file THPs will be developed in the next few release
>> 844 cycles.
1283 845
1284 config EXECMEM !! 846 config ARCH_HAS_PTE_SPECIAL
1285 bool 847 bool
1286 848
1287 config NUMA_MEMBLKS !! 849 #
>> 850 # Some architectures require a special hugepage directory format that is
>> 851 # required to support multiple hugepage sizes. For example a4fe3ce76
>> 852 # "powerpc/mm: Allow more flexible layouts for hugepage pagetables"
>> 853 # introduced it on powerpc. This allows for a more flexible hugepage
>> 854 # pagetable layouts.
>> 855 #
>> 856 config ARCH_HAS_HUGEPD
1288 bool 857 bool
1289 858
1290 config NUMA_EMU !! 859 config MAPPING_DIRTY_HELPERS
1291 bool "NUMA emulation" !! 860 bool
1292 depends on NUMA_MEMBLKS <<
1293 help <<
1294 Enable NUMA emulation. A flat machi <<
1295 into virtual nodes when booted with <<
1296 number of nodes. This is only usefu <<
1297 <<
1298 source "mm/damon/Kconfig" <<
1299 861
1300 endmenu 862 endmenu
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