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Linux/mm/Kconfig

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Diff markup

Differences between /mm/Kconfig (Version linux-6.12-rc7) and /mm/Kconfig (Version linux-5.9.16)


  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         depends on SPARSEMEM || X86_64_ACPI_NUMA
546         depends on SPARSEMEM                   << 
547         depends on ARCH_ENABLE_MEMORY_HOTPLUG     156         depends on ARCH_ENABLE_MEMORY_HOTPLUG
548         depends on 64BIT                       !! 157         depends on 64BIT || BROKEN
549         select NUMA_KEEP_MEMINFO if NUMA          158         select NUMA_KEEP_MEMINFO if NUMA
550                                                   159 
551 if MEMORY_HOTPLUG                              !! 160 config MEMORY_HOTPLUG_SPARSE
                                                   >> 161         def_bool y
                                                   >> 162         depends on SPARSEMEM && MEMORY_HOTPLUG
552                                                   163 
553 config MEMORY_HOTPLUG_DEFAULT_ONLINE              164 config MEMORY_HOTPLUG_DEFAULT_ONLINE
554         bool "Online the newly added memory bl    165         bool "Online the newly added memory blocks by default"
555         depends on MEMORY_HOTPLUG                 166         depends on MEMORY_HOTPLUG
556         help                                      167         help
557           This option sets the default policy     168           This option sets the default policy setting for memory hotplug
558           onlining policy (/sys/devices/system    169           onlining policy (/sys/devices/system/memory/auto_online_blocks) which
559           determines what happens to newly add    170           determines what happens to newly added memory regions. Policy setting
560           can always be changed at runtime.       171           can always be changed at runtime.
561           See Documentation/admin-guide/mm/mem    172           See Documentation/admin-guide/mm/memory-hotplug.rst for more information.
562                                                   173 
563           Say Y here if you want all hot-plugg    174           Say Y here if you want all hot-plugged memory blocks to appear in
564           'online' state by default.              175           'online' state by default.
565           Say N here if you want the default p    176           Say N here if you want the default policy to keep all hot-plugged
566           memory blocks in 'offline' state.       177           memory blocks in 'offline' state.
567                                                   178 
568 config MEMORY_HOTREMOVE                           179 config MEMORY_HOTREMOVE
569         bool "Allow for memory hot remove"        180         bool "Allow for memory hot remove"
                                                   >> 181         select MEMORY_ISOLATION
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)
                                                   >> 287         help
                                                   >> 288           Enable bounce buffers for devices that cannot access
                                                   >> 289           the full range of memory available to the CPU. Enabled
                                                   >> 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
719         help                                      295         help
720           Enable bounce buffers for devices th !! 296           An architecture should select this if it implements the
721           memory available to the CPU. Enabled !! 297           deprecated interface virt_to_bus().  All new architectures
722           selected, but you may say n to overr !! 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/mm/nommu-mmap.rst for more information.
809                                                << 
810 config ARCH_WANT_GENERAL_HUGETLB               << 
811         bool                                   << 
812                                                << 
813 config ARCH_WANTS_THP_SWAP                     << 
814         def_bool n                             << 
815                                                   387 
816 menuconfig TRANSPARENT_HUGEPAGE                !! 388 config 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 7
957         default 8                              << 
958         help                                      520         help
959           CMA allows to create CMA areas for p    521           CMA allows to create CMA areas for particular purpose, mainly,
960           used as device private area. This pa    522           used as device private area. This parameter sets the maximum
961           number of CMA area in the system.       523           number of CMA area in the system.
962                                                   524 
963           If unsure, leave the default value " !! 525           If unsure, leave the default value "7".
964                                                   526 
965 config MEM_SOFT_DIRTY                             527 config MEM_SOFT_DIRTY
966         bool "Track memory changes"               528         bool "Track memory changes"
967         depends on CHECKPOINT_RESTORE && HAVE_    529         depends on CHECKPOINT_RESTORE && HAVE_ARCH_SOFT_DIRTY && PROC_FS
968         select PROC_PAGE_MONITOR                  530         select PROC_PAGE_MONITOR
969         help                                      531         help
970           This option enables memory changes t    532           This option enables memory changes tracking by introducing a
971           soft-dirty bit on pte-s. This bit it    533           soft-dirty bit on pte-s. This bit it set when someone writes
972           into a page just as regular dirty bi    534           into a page just as regular dirty bit, but unlike the latter
973           it can be cleared by hands.             535           it can be cleared by hands.
974                                                   536 
975           See Documentation/admin-guide/mm/sof    537           See Documentation/admin-guide/mm/soft-dirty.rst for more details.
976                                                   538 
                                                   >> 539 config ZSWAP
                                                   >> 540         bool "Compressed cache for swap pages (EXPERIMENTAL)"
                                                   >> 541         depends on FRONTSWAP && CRYPTO=y
                                                   >> 542         select ZPOOL
                                                   >> 543         help
                                                   >> 544           A lightweight compressed cache for swap pages.  It takes
                                                   >> 545           pages that are in the process of being swapped out and attempts to
                                                   >> 546           compress them into a dynamically allocated RAM-based memory pool.
                                                   >> 547           This can result in a significant I/O reduction on swap device and,
                                                   >> 548           in the case where decompressing from RAM is faster that swap device
                                                   >> 549           reads, can also improve workload performance.
                                                   >> 550 
                                                   >> 551           This is marked experimental because it is a new feature (as of
                                                   >> 552           v3.11) that interacts heavily with memory reclaim.  While these
                                                   >> 553           interactions don't cause any known issues on simple memory setups,
                                                   >> 554           they have not be fully explored on the large set of potential
                                                   >> 555           configurations and workloads that exist.
                                                   >> 556 
                                                   >> 557 choice
                                                   >> 558         prompt "Compressed cache for swap pages default compressor"
                                                   >> 559         depends on ZSWAP
                                                   >> 560         default ZSWAP_COMPRESSOR_DEFAULT_LZO
                                                   >> 561         help
                                                   >> 562           Selects the default compression algorithm for the compressed cache
                                                   >> 563           for swap pages.
                                                   >> 564 
                                                   >> 565           For an overview what kind of performance can be expected from
                                                   >> 566           a particular compression algorithm please refer to the benchmarks
                                                   >> 567           available at the following LWN page:
                                                   >> 568           https://lwn.net/Articles/751795/
                                                   >> 569 
                                                   >> 570           If in doubt, select 'LZO'.
                                                   >> 571 
                                                   >> 572           The selection made here can be overridden by using the kernel
                                                   >> 573           command line 'zswap.compressor=' option.
                                                   >> 574 
                                                   >> 575 config ZSWAP_COMPRESSOR_DEFAULT_DEFLATE
                                                   >> 576         bool "Deflate"
                                                   >> 577         select CRYPTO_DEFLATE
                                                   >> 578         help
                                                   >> 579           Use the Deflate algorithm as the default compression algorithm.
                                                   >> 580 
                                                   >> 581 config ZSWAP_COMPRESSOR_DEFAULT_LZO
                                                   >> 582         bool "LZO"
                                                   >> 583         select CRYPTO_LZO
                                                   >> 584         help
                                                   >> 585           Use the LZO algorithm as the default compression algorithm.
                                                   >> 586 
                                                   >> 587 config ZSWAP_COMPRESSOR_DEFAULT_842
                                                   >> 588         bool "842"
                                                   >> 589         select CRYPTO_842
                                                   >> 590         help
                                                   >> 591           Use the 842 algorithm as the default compression algorithm.
                                                   >> 592 
                                                   >> 593 config ZSWAP_COMPRESSOR_DEFAULT_LZ4
                                                   >> 594         bool "LZ4"
                                                   >> 595         select CRYPTO_LZ4
                                                   >> 596         help
                                                   >> 597           Use the LZ4 algorithm as the default compression algorithm.
                                                   >> 598 
                                                   >> 599 config ZSWAP_COMPRESSOR_DEFAULT_LZ4HC
                                                   >> 600         bool "LZ4HC"
                                                   >> 601         select CRYPTO_LZ4HC
                                                   >> 602         help
                                                   >> 603           Use the LZ4HC algorithm as the default compression algorithm.
                                                   >> 604 
                                                   >> 605 config ZSWAP_COMPRESSOR_DEFAULT_ZSTD
                                                   >> 606         bool "zstd"
                                                   >> 607         select CRYPTO_ZSTD
                                                   >> 608         help
                                                   >> 609           Use the zstd algorithm as the default compression algorithm.
                                                   >> 610 endchoice
                                                   >> 611 
                                                   >> 612 config ZSWAP_COMPRESSOR_DEFAULT
                                                   >> 613        string
                                                   >> 614        depends on ZSWAP
                                                   >> 615        default "deflate" if ZSWAP_COMPRESSOR_DEFAULT_DEFLATE
                                                   >> 616        default "lzo" if ZSWAP_COMPRESSOR_DEFAULT_LZO
                                                   >> 617        default "842" if ZSWAP_COMPRESSOR_DEFAULT_842
                                                   >> 618        default "lz4" if ZSWAP_COMPRESSOR_DEFAULT_LZ4
                                                   >> 619        default "lz4hc" if ZSWAP_COMPRESSOR_DEFAULT_LZ4HC
                                                   >> 620        default "zstd" if ZSWAP_COMPRESSOR_DEFAULT_ZSTD
                                                   >> 621        default ""
                                                   >> 622 
                                                   >> 623 choice
                                                   >> 624         prompt "Compressed cache for swap pages default allocator"
                                                   >> 625         depends on ZSWAP
                                                   >> 626         default ZSWAP_ZPOOL_DEFAULT_ZBUD
                                                   >> 627         help
                                                   >> 628           Selects the default allocator for the compressed cache for
                                                   >> 629           swap pages.
                                                   >> 630           The default is 'zbud' for compatibility, however please do
                                                   >> 631           read the description of each of the allocators below before
                                                   >> 632           making a right choice.
                                                   >> 633 
                                                   >> 634           The selection made here can be overridden by using the kernel
                                                   >> 635           command line 'zswap.zpool=' option.
                                                   >> 636 
                                                   >> 637 config ZSWAP_ZPOOL_DEFAULT_ZBUD
                                                   >> 638         bool "zbud"
                                                   >> 639         select ZBUD
                                                   >> 640         help
                                                   >> 641           Use the zbud allocator as the default allocator.
                                                   >> 642 
                                                   >> 643 config ZSWAP_ZPOOL_DEFAULT_Z3FOLD
                                                   >> 644         bool "z3fold"
                                                   >> 645         select Z3FOLD
                                                   >> 646         help
                                                   >> 647           Use the z3fold allocator as the default allocator.
                                                   >> 648 
                                                   >> 649 config ZSWAP_ZPOOL_DEFAULT_ZSMALLOC
                                                   >> 650         bool "zsmalloc"
                                                   >> 651         select ZSMALLOC
                                                   >> 652         help
                                                   >> 653           Use the zsmalloc allocator as the default allocator.
                                                   >> 654 endchoice
                                                   >> 655 
                                                   >> 656 config ZSWAP_ZPOOL_DEFAULT
                                                   >> 657        string
                                                   >> 658        depends on ZSWAP
                                                   >> 659        default "zbud" if ZSWAP_ZPOOL_DEFAULT_ZBUD
                                                   >> 660        default "z3fold" if ZSWAP_ZPOOL_DEFAULT_Z3FOLD
                                                   >> 661        default "zsmalloc" if ZSWAP_ZPOOL_DEFAULT_ZSMALLOC
                                                   >> 662        default ""
                                                   >> 663 
                                                   >> 664 config ZSWAP_DEFAULT_ON
                                                   >> 665         bool "Enable the compressed cache for swap pages by default"
                                                   >> 666         depends on ZSWAP
                                                   >> 667         help
                                                   >> 668           If selected, the compressed cache for swap pages will be enabled
                                                   >> 669           at boot, otherwise it will be disabled.
                                                   >> 670 
                                                   >> 671           The selection made here can be overridden by using the kernel
                                                   >> 672           command line 'zswap.enabled=' option.
                                                   >> 673 
                                                   >> 674 config ZPOOL
                                                   >> 675         tristate "Common API for compressed memory storage"
                                                   >> 676         help
                                                   >> 677           Compressed memory storage API.  This allows using either zbud or
                                                   >> 678           zsmalloc.
                                                   >> 679 
                                                   >> 680 config ZBUD
                                                   >> 681         tristate "Low (Up to 2x) density storage for compressed pages"
                                                   >> 682         help
                                                   >> 683           A special purpose allocator for storing compressed pages.
                                                   >> 684           It is designed to store up to two compressed pages per physical
                                                   >> 685           page.  While this design limits storage density, it has simple and
                                                   >> 686           deterministic reclaim properties that make it preferable to a higher
                                                   >> 687           density approach when reclaim will be used.
                                                   >> 688 
                                                   >> 689 config Z3FOLD
                                                   >> 690         tristate "Up to 3x density storage for compressed pages"
                                                   >> 691         depends on ZPOOL
                                                   >> 692         help
                                                   >> 693           A special purpose allocator for storing compressed pages.
                                                   >> 694           It is designed to store up to three compressed pages per physical
                                                   >> 695           page. It is a ZBUD derivative so the simplicity and determinism are
                                                   >> 696           still there.
                                                   >> 697 
                                                   >> 698 config ZSMALLOC
                                                   >> 699         tristate "Memory allocator for compressed pages"
                                                   >> 700         depends on MMU
                                                   >> 701         help
                                                   >> 702           zsmalloc is a slab-based memory allocator designed to store
                                                   >> 703           compressed RAM pages.  zsmalloc uses virtual memory mapping
                                                   >> 704           in order to reduce fragmentation.  However, this results in a
                                                   >> 705           non-standard allocator interface where a handle, not a pointer, is
                                                   >> 706           returned by an alloc().  This handle must be mapped in order to
                                                   >> 707           access the allocated space.
                                                   >> 708 
                                                   >> 709 config ZSMALLOC_STAT
                                                   >> 710         bool "Export zsmalloc statistics"
                                                   >> 711         depends on ZSMALLOC
                                                   >> 712         select DEBUG_FS
                                                   >> 713         help
                                                   >> 714           This option enables code in the zsmalloc to collect various
                                                   >> 715           statistics about whats happening in zsmalloc and exports that
                                                   >> 716           information to userspace via debugfs.
                                                   >> 717           If unsure, say N.
                                                   >> 718 
977 config GENERIC_EARLY_IOREMAP                      719 config GENERIC_EARLY_IOREMAP
978         bool                                      720         bool
979                                                   721 
980 config STACK_MAX_DEFAULT_SIZE_MB               !! 722 config MAX_STACK_SIZE_MB
981         int "Default maximum user stack size f !! 723         int "Maximum user stack size for 32-bit processes (MB)"
982         default 100                            !! 724         default 80
983         range 8 2048                              725         range 8 2048
984         depends on STACK_GROWSUP && (!64BIT ||    726         depends on STACK_GROWSUP && (!64BIT || COMPAT)
985         help                                      727         help
986           This is the maximum stack size in Me    728           This is the maximum stack size in Megabytes in the VM layout of 32-bit
987           user processes when the stack grows     729           user processes when the stack grows upwards (currently only on parisc
988           arch) when the RLIMIT_STACK hard lim !! 730           arch). The stack will be located at the highest memory address minus
                                                   >> 731           the given value, unless the RLIMIT_STACK hard limit is changed to a
                                                   >> 732           smaller value in which case that is used.
989                                                   733 
990           A sane initial value is 100 MB.      !! 734           A sane initial value is 80 MB.
991                                                   735 
992 config DEFERRED_STRUCT_PAGE_INIT                  736 config DEFERRED_STRUCT_PAGE_INIT
993         bool "Defer initialisation of struct p    737         bool "Defer initialisation of struct pages to kthreads"
994         depends on SPARSEMEM                      738         depends on SPARSEMEM
995         depends on !NEED_PER_CPU_KM               739         depends on !NEED_PER_CPU_KM
996         depends on 64BIT                          740         depends on 64BIT
997         depends on !KMSAN                      << 
998         select PADATA                             741         select PADATA
999         help                                      742         help
1000           Ordinarily all struct pages are ini    743           Ordinarily all struct pages are initialised during early boot in a
1001           single thread. On very large machin    744           single thread. On very large machines this can take a considerable
1002           amount of time. If this option is s    745           amount of time. If this option is set, large machines will bring up
1003           a subset of memmap at boot and then    746           a subset of memmap at boot and then initialise the rest in parallel.
1004           This has a potential performance im    747           This has a potential performance impact on tasks running early in the
1005           lifetime of the system until these     748           lifetime of the system until these kthreads finish the
1006           initialisation.                        749           initialisation.
1007                                                  750 
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                        751 config IDLE_PAGE_TRACKING
1017         bool "Enable idle page tracking"         752         bool "Enable idle page tracking"
1018         depends on SYSFS && MMU                  753         depends on SYSFS && MMU
1019         select PAGE_IDLE_FLAG                 !! 754         select PAGE_EXTENSION if !64BIT
1020         help                                     755         help
1021           This feature allows to estimate the    756           This feature allows to estimate the amount of user pages that have
1022           not been touched during a given per    757           not been touched during a given period of time. This information can
1023           be useful to tune memory cgroup lim    758           be useful to tune memory cgroup limits and/or for job placement
1024           within a compute cluster.              759           within a compute cluster.
1025                                                  760 
1026           See Documentation/admin-guide/mm/id    761           See Documentation/admin-guide/mm/idle_page_tracking.rst for
1027           more details.                          762           more details.
1028                                                  763 
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                       764 config ARCH_HAS_PTE_DEVMAP
1048         bool                                     765         bool
1049                                                  766 
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                               767 config ZONE_DEVICE
1063         bool "Device memory (pmem, HMM, etc..    768         bool "Device memory (pmem, HMM, etc...) hotplug support"
1064         depends on MEMORY_HOTPLUG                769         depends on MEMORY_HOTPLUG
1065         depends on MEMORY_HOTREMOVE              770         depends on MEMORY_HOTREMOVE
1066         depends on SPARSEMEM_VMEMMAP             771         depends on SPARSEMEM_VMEMMAP
1067         depends on ARCH_HAS_PTE_DEVMAP           772         depends on ARCH_HAS_PTE_DEVMAP
1068         select XARRAY_MULTI                      773         select XARRAY_MULTI
1069                                                  774 
1070         help                                     775         help
1071           Device memory hotplug support allow    776           Device memory hotplug support allows for establishing pmem,
1072           or other device driver discovered m    777           or other device driver discovered memory regions, in the
1073           memmap. This allows pfn_to_page() l    778           memmap. This allows pfn_to_page() lookups of otherwise
1074           "device-physical" addresses which i    779           "device-physical" addresses which is needed for using a DAX
1075           mapping in an O_DIRECT operation, a    780           mapping in an O_DIRECT operation, among other things.
1076                                                  781 
1077           If FS_DAX is enabled, then say Y.      782           If FS_DAX is enabled, then say Y.
1078                                                  783 
                                                   >> 784 config DEV_PAGEMAP_OPS
                                                   >> 785         bool
                                                   >> 786 
1079 #                                                787 #
1080 # Helpers to mirror range of the CPU page tab    788 # Helpers to mirror range of the CPU page tables of a process into device page
1081 # tables.                                        789 # tables.
1082 #                                                790 #
1083 config HMM_MIRROR                                791 config HMM_MIRROR
1084         bool                                     792         bool
1085         depends on MMU                           793         depends on MMU
1086                                                  794 
1087 config GET_FREE_REGION                        << 
1088         bool                                  << 
1089                                               << 
1090 config DEVICE_PRIVATE                            795 config DEVICE_PRIVATE
1091         bool "Unaddressable device memory (GP    796         bool "Unaddressable device memory (GPU memory, ...)"
1092         depends on ZONE_DEVICE                   797         depends on ZONE_DEVICE
1093         select GET_FREE_REGION                !! 798         select DEV_PAGEMAP_OPS
1094                                                  799 
1095         help                                     800         help
1096           Allows creation of struct pages to     801           Allows creation of struct pages to represent unaddressable device
1097           memory; i.e., memory that is only a    802           memory; i.e., memory that is only accessible from the device (or
1098           group of devices). You likely also     803           group of devices). You likely also want to select HMM_MIRROR.
1099                                                  804 
1100 config VMAP_PFN                               !! 805 config FRAME_VECTOR
1101         bool                                     806         bool
1102                                                  807 
1103 config ARCH_USES_HIGH_VMA_FLAGS                  808 config ARCH_USES_HIGH_VMA_FLAGS
1104         bool                                     809         bool
1105 config ARCH_HAS_PKEYS                            810 config ARCH_HAS_PKEYS
1106         bool                                     811         bool
1107                                                  812 
1108 config ARCH_USES_PG_ARCH_2                    << 
1109         bool                                  << 
1110 config ARCH_USES_PG_ARCH_3                    << 
1111         bool                                  << 
1112                                               << 
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                              813 config PERCPU_STATS
1123         bool "Collect percpu memory statistic    814         bool "Collect percpu memory statistics"
1124         help                                     815         help
1125           This feature collects and exposes s    816           This feature collects and exposes statistics via debugfs. The
1126           information includes global and per    817           information includes global and per chunk statistics, which can
1127           be used to help understand percpu m    818           be used to help understand percpu memory usage.
1128                                                  819 
1129 config GUP_TEST                               !! 820 config GUP_BENCHMARK
1130         bool "Enable infrastructure for get_u !! 821         bool "Enable infrastructure for get_user_pages_fast() benchmarking"
1131         depends on DEBUG_FS                   << 
1132         help                                     822         help
1133           Provides /sys/kernel/debug/gup_test !! 823           Provides /sys/kernel/debug/gup_benchmark that helps with testing
1134           to make ioctl calls that can launch !! 824           performance of get_user_pages_fast().
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                                                  825 
1141           There is also a sub-test that allow !! 826           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                                                  827 
1147           See tools/testing/selftests/mm/gup_ !! 828 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                                     829         bool
1154                                                  830 
1155 config DMAPOOL_TEST                           !! 831 config READ_ONLY_THP_FOR_FS
1156         tristate "Enable a module to run time !! 832         bool "Read-only THP for filesystems (EXPERIMENTAL)"
1157         depends on HAS_DMA                    !! 833         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                                                  834 
1251 config LRU_GEN_STATS                          << 
1252         bool "Full stats for debugging"       << 
1253         depends on LRU_GEN                    << 
1254         help                                     835         help
1255           Do not enable this option unless yo !! 836           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                                                  837 
1281 config IOMMU_MM_DATA                          !! 838           This is marked experimental because it is a new feature. Write
1282         bool                                  !! 839           support of file THPs will be developed in the next few release
                                                   >> 840           cycles.
1283                                                  841 
1284 config EXECMEM                                !! 842 config ARCH_HAS_PTE_SPECIAL
1285         bool                                     843         bool
1286                                                  844 
1287 config NUMA_MEMBLKS                           !! 845 #
                                                   >> 846 # Some architectures require a special hugepage directory format that is
                                                   >> 847 # required to support multiple hugepage sizes. For example a4fe3ce76
                                                   >> 848 # "powerpc/mm: Allow more flexible layouts for hugepage pagetables"
                                                   >> 849 # introduced it on powerpc.  This allows for a more flexible hugepage
                                                   >> 850 # pagetable layouts.
                                                   >> 851 #
                                                   >> 852 config ARCH_HAS_HUGEPD
1288         bool                                     853         bool
1289                                                  854 
1290 config NUMA_EMU                               !! 855 config MAPPING_DIRTY_HELPERS
1291         bool "NUMA emulation"                 !! 856         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                                                  857 
1300 endmenu                                          858 endmenu
                                                      

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