mm/vmstat.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  linux/mm/vmstat.c
   4  *
   5  *  Manages VM statistics
   6  *  Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
   7  *
   8  *  zoned VM statistics
   9  *  Copyright (C) 2006 Silicon Graphics, Inc.,
  10  *              Christoph Lameter <christoph@lameter.com>
  11  *  Copyright (C) 2008-2014 Christoph Lameter
  12  */
  13 #include <linux/fs.h>
  14 #include <linux/mm.h>
  15 #include <linux/err.h>
  16 #include <linux/module.h>
  17 #include <linux/slab.h>
  18 #include <linux/cpu.h>
  19 #include <linux/cpumask.h>
  20 #include <linux/vmstat.h>
  21 #include <linux/proc_fs.h>
  22 #include <linux/seq_file.h>
  23 #include <linux/debugfs.h>
  24 #include <linux/sched.h>
  25 #include <linux/math64.h>
  26 #include <linux/writeback.h>
  27 #include <linux/compaction.h>
  28 #include <linux/mm_inline.h>
  29 #include <linux/page_ext.h>
  30 #include <linux/page_owner.h>
  31
  32 #include "internal.h"
  33
  34 #define NUMA_STATS_THRESHOLD (U16_MAX - 2)
  35
  36 #ifdef CONFIG_NUMA
  37 int sysctl_vm_numa_stat = ENABLE_NUMA_STAT;
  38
  39 /* zero numa counters within a zone */
  40 static void zero_zone_numa_counters(struct zone *zone)
  41 {
  42         int item, cpu;
  43
  44         for (item = 0; item < NR_VM_NUMA_STAT_ITEMS; item++) {
  45                 atomic_long_set(&zone->vm_numa_stat[item], 0);
  46                 for_each_online_cpu(cpu)
  47                         per_cpu_ptr(zone->per_cpu_zonestats, cpu)->vm_numa_stat_diff[item]
  48                                                 = 0;
  49         }
  50 }
  51
  52 /* zero numa counters of all the populated zones */
  53 static void zero_zones_numa_counters(void)
  54 {
  55         struct zone *zone;
  56
  57         for_each_populated_zone(zone)
  58                 zero_zone_numa_counters(zone);
  59 }
  60
  61 /* zero global numa counters */
  62 static void zero_global_numa_counters(void)
  63 {
  64         int item;
  65
  66         for (item = 0; item < NR_VM_NUMA_STAT_ITEMS; item++)
  67                 atomic_long_set(&vm_numa_stat[item], 0);
  68 }
  69
  70 static void invalid_numa_statistics(void)
  71 {
  72         zero_zones_numa_counters();
  73         zero_global_numa_counters();
  74 }
  75
  76 static DEFINE_MUTEX(vm_numa_stat_lock);
  77
  78 int sysctl_vm_numa_stat_handler(struct ctl_table *table, int write,
  79                 void *buffer, size_t *length, loff_t *ppos)
  80 {
  81         int ret, oldval;
  82
  83         mutex_lock(&vm_numa_stat_lock);
  84         if (write)
  85                 oldval = sysctl_vm_numa_stat;
  86         ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
  87         if (ret || !write)
  88                 goto out;
  89
  90         if (oldval == sysctl_vm_numa_stat)
  91                 goto out;
  92         else if (sysctl_vm_numa_stat == ENABLE_NUMA_STAT) {
  93                 static_branch_enable(&vm_numa_stat_key);
  94                 pr_info("enable numa statistics\n");
  95         } else {
  96                 static_branch_disable(&vm_numa_stat_key);
  97                 invalid_numa_statistics();
  98                 pr_info("disable numa statistics, and clear numa counters\n");
  99         }
 100
 101 out:
 102         mutex_unlock(&vm_numa_stat_lock);
 103         return ret;
 104 }
 105 #endif
 106
 107 #ifdef CONFIG_VM_EVENT_COUNTERS
 108 DEFINE_PER_CPU(struct vm_event_state, vm_event_states) = {{0}};
 109 EXPORT_PER_CPU_SYMBOL(vm_event_states);
 110
 111 static void sum_vm_events(unsigned long *ret)
 112 {
 113         int cpu;
 114         int i;
 115
 116         memset(ret, 0, NR_VM_EVENT_ITEMS * sizeof(unsigned long));
 117
 118         for_each_online_cpu(cpu) {
 119                 struct vm_event_state *this = &per_cpu(vm_event_states, cpu);
 120
 121                 for (i = 0; i < NR_VM_EVENT_ITEMS; i++)
 122                         ret[i] += this->event[i];
 123         }
 124 }
 125
 126 /*
 127  * Accumulate the vm event counters across all CPUs.
 128  * The result is unavoidably approximate - it can change
 129  * during and after execution of this function.
 130 */
 131 void all_vm_events(unsigned long *ret)
 132 {
 133         get_online_cpus();
 134         sum_vm_events(ret);
 135         put_online_cpus();
 136 }
 137 EXPORT_SYMBOL_GPL(all_vm_events);
 138
 139 /*
 140  * Fold the foreign cpu events into our own.
 141  *
 142  * This is adding to the events on one processor
 143  * but keeps the global counts constant.
 144  */
 145 void vm_events_fold_cpu(int cpu)
 146 {
 147         struct vm_event_state *fold_state = &per_cpu(vm_event_states, cpu);
 148         int i;
 149
 150         for (i = 0; i < NR_VM_EVENT_ITEMS; i++) {
 151                 count_vm_events(i, fold_state->event[i]);
 152                 fold_state->event[i] = 0;
 153         }
 154 }
 155
 156 #endif /* CONFIG_VM_EVENT_COUNTERS */
 157
 158 /*
 159  * Manage combined zone based / global counters
 160  *
 161  * vm_stat contains the global counters
 162  */
 163 atomic_long_t vm_zone_stat[NR_VM_ZONE_STAT_ITEMS] __cacheline_aligned_in_smp;
 164 atomic_long_t vm_numa_stat[NR_VM_NUMA_STAT_ITEMS] __cacheline_aligned_in_smp;
 165 atomic_long_t vm_node_stat[NR_VM_NODE_STAT_ITEMS] __cacheline_aligned_in_smp;
 166 EXPORT_SYMBOL(vm_zone_stat);
 167 EXPORT_SYMBOL(vm_numa_stat);
 168 EXPORT_SYMBOL(vm_node_stat);
 169
 170 #ifdef CONFIG_SMP
 171
 172 int calculate_pressure_threshold(struct zone *zone)
 173 {
 174         int threshold;
 175         int watermark_distance;
 176
 177         /*
 178          * As vmstats are not up to date, there is drift between the estimated
 179          * and real values. For high thresholds and a high number of CPUs, it
 180          * is possible for the min watermark to be breached while the estimated
 181          * value looks fine. The pressure threshold is a reduced value such
 182          * that even the maximum amount of drift will not accidentally breach
 183          * the min watermark
 184          */
 185         watermark_distance = low_wmark_pages(zone) - min_wmark_pages(zone);
 186         threshold = max(1, (int)(watermark_distance / num_online_cpus()));
 187
 188         /*
 189          * Maximum threshold is 125
 190          */
 191         threshold = min(125, threshold);
 192
 193         return threshold;
 194 }
 195
 196 int calculate_normal_threshold(struct zone *zone)
 197 {
 198         int threshold;
 199         int mem;        /* memory in 128 MB units */
 200
 201         /*
 202          * The threshold scales with the number of processors and the amount
 203          * of memory per zone. More memory means that we can defer updates for
 204          * longer, more processors could lead to more contention.
 205          * fls() is used to have a cheap way of logarithmic scaling.
 206          *
 207          * Some sample thresholds:
 208          *
 209          * Threshold    Processors      (fls)   Zonesize        fls(mem+1)
 210          * ------------------------------------------------------------------
 211          * 8            1               1       0.9-1 GB        4
 212          * 16           2               2       0.9-1 GB        4
 213          * 20           2               2       1-2 GB          5
 214          * 24           2               2       2-4 GB          6
 215          * 28           2               2       4-8 GB          7
 216          * 32           2               2       8-16 GB         8
 217          * 4            2               2       <128M           1
 218          * 30           4               3       2-4 GB          5
 219          * 48           4               3       8-16 GB         8
 220          * 32           8               4       1-2 GB          4
 221          * 32           8               4       0.9-1GB         4
 222          * 10           16              5       <128M           1
 223          * 40           16              5       900M            4
 224          * 70           64              7       2-4 GB          5
 225          * 84           64              7       4-8 GB          6
 226          * 108          512             9       4-8 GB          6
 227          * 125          1024            10      8-16 GB         8
 228          * 125          1024            10      16-32 GB        9
 229          */
 230
 231         mem = zone_managed_pages(zone) >> (27 - PAGE_SHIFT);
 232
 233         threshold = 2 * fls(num_online_cpus()) * (1 + fls(mem));
 234
 235         /*
 236          * Maximum threshold is 125
 237          */
 238         threshold = min(125, threshold);
 239
 240         return threshold;
 241 }
 242
 243 /*
 244  * Refresh the thresholds for each zone.
 245  */
 246 void refresh_zone_stat_thresholds(void)
 247 {
 248         struct pglist_data *pgdat;
 249         struct zone *zone;
 250         int cpu;
 251         int threshold;
 252
 253         /* Zero current pgdat thresholds */
 254         for_each_online_pgdat(pgdat) {
 255                 for_each_online_cpu(cpu) {
 256                         per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold = 0;
 257                 }
 258         }
 259
 260         for_each_populated_zone(zone) {
 261                 struct pglist_data *pgdat = zone->zone_pgdat;
 262                 unsigned long max_drift, tolerate_drift;
 263
 264                 threshold = calculate_normal_threshold(zone);
 265
 266                 for_each_online_cpu(cpu) {
 267                         int pgdat_threshold;
 268
 269                         per_cpu_ptr(zone->per_cpu_zonestats, cpu)->stat_threshold
 270                                                         = threshold;
 271
 272                         /* Base nodestat threshold on the largest populated zone. */
 273                         pgdat_threshold = per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold;
 274                         per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold
 275                                 = max(threshold, pgdat_threshold);
 276                 }
 277
 278                 /*
 279                  * Only set percpu_drift_mark if there is a danger that
 280                  * NR_FREE_PAGES reports the low watermark is ok when in fact
 281                  * the min watermark could be breached by an allocation
 282                  */
 283                 tolerate_drift = low_wmark_pages(zone) - min_wmark_pages(zone);
 284                 max_drift = num_online_cpus() * threshold;
 285                 if (max_drift > tolerate_drift)
 286                         zone->percpu_drift_mark = high_wmark_pages(zone) +
 287                                         max_drift;
 288         }
 289 }
 290
 291 void set_pgdat_percpu_threshold(pg_data_t *pgdat,
 292                                 int (*calculate_pressure)(struct zone *))
 293 {
 294         struct zone *zone;
 295         int cpu;
 296         int threshold;
 297         int i;
 298
 299         for (i = 0; i < pgdat->nr_zones; i++) {
 300                 zone = &pgdat->node_zones[i];
 301                 if (!zone->percpu_drift_mark)
 302                         continue;
 303
 304                 threshold = (*calculate_pressure)(zone);
 305                 for_each_online_cpu(cpu)
 306                         per_cpu_ptr(zone->per_cpu_zonestats, cpu)->stat_threshold
 307                                                         = threshold;
 308         }
 309 }
 310
 311 /*
 312  * For use when we know that interrupts are disabled,
 313  * or when we know that preemption is disabled and that
 314  * particular counter cannot be updated from interrupt context.
 315  */
 316 void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 317                            long delta)
 318 {
 319         struct per_cpu_zonestat __percpu *pcp = zone->per_cpu_zonestats;
 320         s8 __percpu *p = pcp->vm_stat_diff + item;
 321         long x;
 322         long t;
 323
 324         x = delta + __this_cpu_read(*p);
 325
 326         t = __this_cpu_read(pcp->stat_threshold);
 327
 328         if (unlikely(abs(x) > t)) {
 329                 zone_page_state_add(x, zone, item);
 330                 x = 0;
 331         }
 332         __this_cpu_write(*p, x);
 333 }
 334 EXPORT_SYMBOL(__mod_zone_page_state);
 335
 336 void __mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
 337                                 long delta)
 338 {
 339         struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
 340         s8 __percpu *p = pcp->vm_node_stat_diff + item;
 341         long x;
 342         long t;
 343
 344         if (vmstat_item_in_bytes(item)) {
 345                 /*
 346                  * Only cgroups use subpage accounting right now; at
 347                  * the global level, these items still change in
 348                  * multiples of whole pages. Store them as pages
 349                  * internally to keep the per-cpu counters compact.
 350                  */
 351                 VM_WARN_ON_ONCE(delta & (PAGE_SIZE - 1));
 352                 delta >>= PAGE_SHIFT;
 353         }
 354
 355         x = delta + __this_cpu_read(*p);
 356
 357         t = __this_cpu_read(pcp->stat_threshold);
 358
 359         if (unlikely(abs(x) > t)) {
 360                 node_page_state_add(x, pgdat, item);
 361                 x = 0;
 362         }
 363         __this_cpu_write(*p, x);
 364 }
 365 EXPORT_SYMBOL(__mod_node_page_state);
 366
 367 /*
 368  * Optimized increment and decrement functions.
 369  *
 370  * These are only for a single page and therefore can take a struct page *
 371  * argument instead of struct zone *. This allows the inclusion of the code
 372  * generated for page_zone(page) into the optimized functions.
 373  *
 374  * No overflow check is necessary and therefore the differential can be
 375  * incremented or decremented in place which may allow the compilers to
 376  * generate better code.
 377  * The increment or decrement is known and therefore one boundary check can
 378  * be omitted.
 379  *
 380  * NOTE: These functions are very performance sensitive. Change only
 381  * with care.
 382  *
 383  * Some processors have inc/dec instructions that are atomic vs an interrupt.
 384  * However, the code must first determine the differential location in a zone
 385  * based on the processor number and then inc/dec the counter. There is no
 386  * guarantee without disabling preemption that the processor will not change
 387  * in between and therefore the atomicity vs. interrupt cannot be exploited
 388  * in a useful way here.
 389  */
 390 void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
 391 {
 392         struct per_cpu_zonestat __percpu *pcp = zone->per_cpu_zonestats;
 393         s8 __percpu *p = pcp->vm_stat_diff + item;
 394         s8 v, t;
 395
 396         v = __this_cpu_inc_return(*p);
 397         t = __this_cpu_read(pcp->stat_threshold);
 398         if (unlikely(v > t)) {
 399                 s8 overstep = t >> 1;
 400
 401                 zone_page_state_add(v + overstep, zone, item);
 402                 __this_cpu_write(*p, -overstep);
 403         }
 404 }
 405
 406 void __inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
 407 {
 408         struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
 409         s8 __percpu *p = pcp->vm_node_stat_diff + item;
 410         s8 v, t;
 411
 412         VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
 413
 414         v = __this_cpu_inc_return(*p);
 415         t = __this_cpu_read(pcp->stat_threshold);
 416         if (unlikely(v > t)) {
 417                 s8 overstep = t >> 1;
 418
 419                 node_page_state_add(v + overstep, pgdat, item);
 420                 __this_cpu_write(*p, -overstep);
 421         }
 422 }
 423
 424 void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
 425 {
 426         __inc_zone_state(page_zone(page), item);
 427 }
 428 EXPORT_SYMBOL(__inc_zone_page_state);
 429
 430 void __inc_node_page_state(struct page *page, enum node_stat_item item)
 431 {
 432         __inc_node_state(page_pgdat(page), item);
 433 }
 434 EXPORT_SYMBOL(__inc_node_page_state);
 435
 436 void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
 437 {
 438         struct per_cpu_zonestat __percpu *pcp = zone->per_cpu_zonestats;
 439         s8 __percpu *p = pcp->vm_stat_diff + item;
 440         s8 v, t;
 441
 442         v = __this_cpu_dec_return(*p);
 443         t = __this_cpu_read(pcp->stat_threshold);
 444         if (unlikely(v < - t)) {
 445                 s8 overstep = t >> 1;
 446
 447                 zone_page_state_add(v - overstep, zone, item);
 448                 __this_cpu_write(*p, overstep);
 449         }
 450 }
 451
 452 void __dec_node_state(struct pglist_data *pgdat, enum node_stat_item item)
 453 {
 454         struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
 455         s8 __percpu *p = pcp->vm_node_stat_diff + item;
 456         s8 v, t;
 457
 458         VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
 459
 460         v = __this_cpu_dec_return(*p);
 461         t = __this_cpu_read(pcp->stat_threshold);
 462         if (unlikely(v < - t)) {
 463                 s8 overstep = t >> 1;
 464
 465                 node_page_state_add(v - overstep, pgdat, item);
 466                 __this_cpu_write(*p, overstep);
 467         }
 468 }
 469
 470 void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
 471 {
 472         __dec_zone_state(page_zone(page), item);
 473 }
 474 EXPORT_SYMBOL(__dec_zone_page_state);
 475
 476 void __dec_node_page_state(struct page *page, enum node_stat_item item)
 477 {
 478         __dec_node_state(page_pgdat(page), item);
 479 }
 480 EXPORT_SYMBOL(__dec_node_page_state);
 481
 482 #ifdef CONFIG_HAVE_CMPXCHG_LOCAL
 483 /*
 484  * If we have cmpxchg_local support then we do not need to incur the overhead
 485  * that comes with local_irq_save/restore if we use this_cpu_cmpxchg.
 486  *
 487  * mod_state() modifies the zone counter state through atomic per cpu
 488  * operations.
 489  *
 490  * Overstep mode specifies how overstep should handled:
 491  *     0       No overstepping
 492  *     1       Overstepping half of threshold
 493  *     -1      Overstepping minus half of threshold
 494 */
 495 static inline void mod_zone_state(struct zone *zone,
 496        enum zone_stat_item item, long delta, int overstep_mode)
 497 {
 498         struct per_cpu_zonestat __percpu *pcp = zone->per_cpu_zonestats;
 499         s8 __percpu *p = pcp->vm_stat_diff + item;
 500         long o, n, t, z;
 501
 502         do {
 503                 z = 0;  /* overflow to zone counters */
 504
 505                 /*
 506                  * The fetching of the stat_threshold is racy. We may apply
 507                  * a counter threshold to the wrong the cpu if we get
 508                  * rescheduled while executing here. However, the next
 509                  * counter update will apply the threshold again and
 510                  * therefore bring the counter under the threshold again.
 511                  *
 512                  * Most of the time the thresholds are the same anyways
 513                  * for all cpus in a zone.
 514                  */
 515                 t = this_cpu_read(pcp->stat_threshold);
 516
 517                 o = this_cpu_read(*p);
 518                 n = delta + o;
 519
 520                 if (abs(n) > t) {
 521                         int os = overstep_mode * (t >> 1) ;
 522
 523                         /* Overflow must be added to zone counters */
 524                         z = n + os;
 525                         n = -os;
 526                 }
 527         } while (this_cpu_cmpxchg(*p, o, n) != o);
 528
 529         if (z)
 530                 zone_page_state_add(z, zone, item);
 531 }
 532
 533 void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 534                          long delta)
 535 {
 536         mod_zone_state(zone, item, delta, 0);
 537 }
 538 EXPORT_SYMBOL(mod_zone_page_state);
 539
 540 void inc_zone_page_state(struct page *page, enum zone_stat_item item)
 541 {
 542         mod_zone_state(page_zone(page), item, 1, 1);
 543 }
 544 EXPORT_SYMBOL(inc_zone_page_state);
 545
 546 void dec_zone_page_state(struct page *page, enum zone_stat_item item)
 547 {
 548         mod_zone_state(page_zone(page), item, -1, -1);
 549 }
 550 EXPORT_SYMBOL(dec_zone_page_state);
 551
 552 static inline void mod_node_state(struct pglist_data *pgdat,
 553        enum node_stat_item item, int delta, int overstep_mode)
 554 {
 555         struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
 556         s8 __percpu *p = pcp->vm_node_stat_diff + item;
 557         long o, n, t, z;
 558
 559         if (vmstat_item_in_bytes(item)) {
 560                 /*
 561                  * Only cgroups use subpage accounting right now; at
 562                  * the global level, these items still change in
 563                  * multiples of whole pages. Store them as pages
 564                  * internally to keep the per-cpu counters compact.
 565                  */
 566                 VM_WARN_ON_ONCE(delta & (PAGE_SIZE - 1));
 567                 delta >>= PAGE_SHIFT;
 568         }
 569
 570         do {
 571                 z = 0;  /* overflow to node counters */
 572
 573                 /*
 574                  * The fetching of the stat_threshold is racy. We may apply
 575                  * a counter threshold to the wrong the cpu if we get
 576                  * rescheduled while executing here. However, the next
 577                  * counter update will apply the threshold again and
 578                  * therefore bring the counter under the threshold again.
 579                  *
 580                  * Most of the time the thresholds are the same anyways
 581                  * for all cpus in a node.
 582                  */
 583                 t = this_cpu_read(pcp->stat_threshold);
 584
 585                 o = this_cpu_read(*p);
 586                 n = delta + o;
 587
 588                 if (abs(n) > t) {
 589                         int os = overstep_mode * (t >> 1) ;
 590
 591                         /* Overflow must be added to node counters */
 592                         z = n + os;
 593                         n = -os;
 594                 }
 595         } while (this_cpu_cmpxchg(*p, o, n) != o);
 596
 597         if (z)
 598                 node_page_state_add(z, pgdat, item);
 599 }
 600
 601 void mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
 602                                         long delta)
 603 {
 604         mod_node_state(pgdat, item, delta, 0);
 605 }
 606 EXPORT_SYMBOL(mod_node_page_state);
 607
 608 void inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
 609 {
 610         mod_node_state(pgdat, item, 1, 1);
 611 }
 612
 613 void inc_node_page_state(struct page *page, enum node_stat_item item)
 614 {
 615         mod_node_state(page_pgdat(page), item, 1, 1);
 616 }
 617 EXPORT_SYMBOL(inc_node_page_state);
 618
 619 void dec_node_page_state(struct page *page, enum node_stat_item item)
 620 {
 621         mod_node_state(page_pgdat(page), item, -1, -1);
 622 }
 623 EXPORT_SYMBOL(dec_node_page_state);
 624 #else
 625 /*
 626  * Use interrupt disable to serialize counter updates
 627  */
 628 void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 629                          long delta)
 630 {
 631         unsigned long flags;
 632
 633         local_irq_save(flags);
 634         __mod_zone_page_state(zone, item, delta);
 635         local_irq_restore(flags);
 636 }
 637 EXPORT_SYMBOL(mod_zone_page_state);
 638
 639 void inc_zone_page_state(struct page *page, enum zone_stat_item item)
 640 {
 641         unsigned long flags;
 642         struct zone *zone;
 643
 644         zone = page_zone(page);
 645         local_irq_save(flags);
 646         __inc_zone_state(zone, item);
 647         local_irq_restore(flags);
 648 }
 649 EXPORT_SYMBOL(inc_zone_page_state);
 650
 651 void dec_zone_page_state(struct page *page, enum zone_stat_item item)
 652 {
 653         unsigned long flags;
 654
 655         local_irq_save(flags);
 656         __dec_zone_page_state(page, item);
 657         local_irq_restore(flags);
 658 }
 659 EXPORT_SYMBOL(dec_zone_page_state);
 660
 661 void inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
 662 {
 663         unsigned long flags;
 664
 665         local_irq_save(flags);
 666         __inc_node_state(pgdat, item);
 667         local_irq_restore(flags);
 668 }
 669 EXPORT_SYMBOL(inc_node_state);
 670
 671 void mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
 672                                         long delta)
 673 {
 674         unsigned long flags;
 675
 676         local_irq_save(flags);
 677         __mod_node_page_state(pgdat, item, delta);
 678         local_irq_restore(flags);
 679 }
 680 EXPORT_SYMBOL(mod_node_page_state);
 681
 682 void inc_node_page_state(struct page *page, enum node_stat_item item)
 683 {
 684         unsigned long flags;
 685         struct pglist_data *pgdat;
 686
 687         pgdat = page_pgdat(page);
 688         local_irq_save(flags);
 689         __inc_node_state(pgdat, item);
 690         local_irq_restore(flags);
 691 }
 692 EXPORT_SYMBOL(inc_node_page_state);
 693
 694 void dec_node_page_state(struct page *page, enum node_stat_item item)
 695 {
 696         unsigned long flags;
 697
 698         local_irq_save(flags);
 699         __dec_node_page_state(page, item);
 700         local_irq_restore(flags);
 701 }
 702 EXPORT_SYMBOL(dec_node_page_state);
 703 #endif
 704
 705 /*
 706  * Fold a differential into the global counters.
 707  * Returns the number of counters updated.
 708  */
 709 #ifdef CONFIG_NUMA
 710 static int fold_diff(int *zone_diff, int *numa_diff, int *node_diff)
 711 {
 712         int i;
 713         int changes = 0;
 714
 715         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 716                 if (zone_diff[i]) {
 717                         atomic_long_add(zone_diff[i], &vm_zone_stat[i]);
 718                         changes++;
 719         }
 720
 721         for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
 722                 if (numa_diff[i]) {
 723                         atomic_long_add(numa_diff[i], &vm_numa_stat[i]);
 724                         changes++;
 725         }
 726
 727         for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
 728                 if (node_diff[i]) {
 729                         atomic_long_add(node_diff[i], &vm_node_stat[i]);
 730                         changes++;
 731         }
 732         return changes;
 733 }
 734 #else
 735 static int fold_diff(int *zone_diff, int *node_diff)
 736 {
 737         int i;
 738         int changes = 0;
 739
 740         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 741                 if (zone_diff[i]) {
 742                         atomic_long_add(zone_diff[i], &vm_zone_stat[i]);
 743                         changes++;
 744         }
 745
 746         for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
 747                 if (node_diff[i]) {
 748                         atomic_long_add(node_diff[i], &vm_node_stat[i]);
 749                         changes++;
 750         }
 751         return changes;
 752 }
 753 #endif /* CONFIG_NUMA */
 754
 755 /*
 756  * Update the zone counters for the current cpu.
 757  *
 758  * Note that refresh_cpu_vm_stats strives to only access
 759  * node local memory. The per cpu pagesets on remote zones are placed
 760  * in the memory local to the processor using that pageset. So the
 761  * loop over all zones will access a series of cachelines local to
 762  * the processor.
 763  *
 764  * The call to zone_page_state_add updates the cachelines with the
 765  * statistics in the remote zone struct as well as the global cachelines
 766  * with the global counters. These could cause remote node cache line
 767  * bouncing and will have to be only done when necessary.
 768  *
 769  * The function returns the number of global counters updated.
 770  */
 771 static int refresh_cpu_vm_stats(bool do_pagesets)
 772 {
 773         struct pglist_data *pgdat;
 774         struct zone *zone;
 775         int i;
 776         int global_zone_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
 777 #ifdef CONFIG_NUMA
 778         int global_numa_diff[NR_VM_NUMA_STAT_ITEMS] = { 0, };
 779 #endif
 780         int global_node_diff[NR_VM_NODE_STAT_ITEMS] = { 0, };
 781         int changes = 0;
 782
 783         for_each_populated_zone(zone) {
 784                 struct per_cpu_zonestat __percpu *pzstats = zone->per_cpu_zonestats;
 785 #ifdef CONFIG_NUMA
 786                 struct per_cpu_pages __percpu *pcp = zone->per_cpu_pageset;
 787 #endif
 788
 789                 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
 790                         int v;
 791
 792                         v = this_cpu_xchg(pzstats->vm_stat_diff[i], 0);
 793                         if (v) {
 794
 795                                 atomic_long_add(v, &zone->vm_stat[i]);
 796                                 global_zone_diff[i] += v;
 797 #ifdef CONFIG_NUMA
 798                                 /* 3 seconds idle till flush */
 799                                 __this_cpu_write(pcp->expire, 3);
 800 #endif
 801                         }
 802                 }
 803 #ifdef CONFIG_NUMA
 804                 for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++) {
 805                         int v;
 806
 807                         v = this_cpu_xchg(pzstats->vm_numa_stat_diff[i], 0);
 808                         if (v) {
 809
 810                                 atomic_long_add(v, &zone->vm_numa_stat[i]);
 811                                 global_numa_diff[i] += v;
 812                                 __this_cpu_write(pcp->expire, 3);
 813                         }
 814                 }
 815
 816                 if (do_pagesets) {
 817                         cond_resched();
 818                         /*
 819                          * Deal with draining the remote pageset of this
 820                          * processor
 821                          *
 822                          * Check if there are pages remaining in this pageset
 823                          * if not then there is nothing to expire.
 824                          */
 825                         if (!__this_cpu_read(pcp->expire) ||
 826                                !__this_cpu_read(pcp->count))
 827                                 continue;
 828
 829                         /*
 830                          * We never drain zones local to this processor.
 831                          */
 832                         if (zone_to_nid(zone) == numa_node_id()) {
 833                                 __this_cpu_write(pcp->expire, 0);
 834                                 continue;
 835                         }
 836
 837                         if (__this_cpu_dec_return(pcp->expire))
 838                                 continue;
 839
 840                         if (__this_cpu_read(pcp->count)) {
 841                                 drain_zone_pages(zone, this_cpu_ptr(pcp));
 842                                 changes++;
 843                         }
 844                 }
 845 #endif
 846         }
 847
 848         for_each_online_pgdat(pgdat) {
 849                 struct per_cpu_nodestat __percpu *p = pgdat->per_cpu_nodestats;
 850
 851                 for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
 852                         int v;
 853
 854                         v = this_cpu_xchg(p->vm_node_stat_diff[i], 0);
 855                         if (v) {
 856                                 atomic_long_add(v, &pgdat->vm_stat[i]);
 857                                 global_node_diff[i] += v;
 858                         }
 859                 }
 860         }
 861
 862 #ifdef CONFIG_NUMA
 863         changes += fold_diff(global_zone_diff, global_numa_diff,
 864                              global_node_diff);
 865 #else
 866         changes += fold_diff(global_zone_diff, global_node_diff);
 867 #endif
 868         return changes;
 869 }
 870
 871 /*
 872  * Fold the data for an offline cpu into the global array.
 873  * There cannot be any access by the offline cpu and therefore
 874  * synchronization is simplified.
 875  */
 876 void cpu_vm_stats_fold(int cpu)
 877 {
 878         struct pglist_data *pgdat;
 879         struct zone *zone;
 880         int i;
 881         int global_zone_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
 882 #ifdef CONFIG_NUMA
 883         int global_numa_diff[NR_VM_NUMA_STAT_ITEMS] = { 0, };
 884 #endif
 885         int global_node_diff[NR_VM_NODE_STAT_ITEMS] = { 0, };
 886
 887         for_each_populated_zone(zone) {
 888                 struct per_cpu_zonestat *pzstats;
 889
 890                 pzstats = per_cpu_ptr(zone->per_cpu_zonestats, cpu);
 891
 892                 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 893                         if (pzstats->vm_stat_diff[i]) {
 894                                 int v;
 895
 896                                 v = pzstats->vm_stat_diff[i];
 897                                 pzstats->vm_stat_diff[i] = 0;
 898                                 atomic_long_add(v, &zone->vm_stat[i]);
 899                                 global_zone_diff[i] += v;
 900                         }
 901
 902 #ifdef CONFIG_NUMA
 903                 for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
 904                         if (pzstats->vm_numa_stat_diff[i]) {
 905                                 int v;
 906
 907                                 v = pzstats->vm_numa_stat_diff[i];
 908                                 pzstats->vm_numa_stat_diff[i] = 0;
 909                                 atomic_long_add(v, &zone->vm_numa_stat[i]);
 910                                 global_numa_diff[i] += v;
 911                         }
 912 #endif
 913         }
 914
 915         for_each_online_pgdat(pgdat) {
 916                 struct per_cpu_nodestat *p;
 917
 918                 p = per_cpu_ptr(pgdat->per_cpu_nodestats, cpu);
 919
 920                 for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
 921                         if (p->vm_node_stat_diff[i]) {
 922                                 int v;
 923
 924                                 v = p->vm_node_stat_diff[i];
 925                                 p->vm_node_stat_diff[i] = 0;
 926                                 atomic_long_add(v, &pgdat->vm_stat[i]);
 927                                 global_node_diff[i] += v;
 928                         }
 929         }
 930
 931 #ifdef CONFIG_NUMA
 932         fold_diff(global_zone_diff, global_numa_diff, global_node_diff);
 933 #else
 934         fold_diff(global_zone_diff, global_node_diff);
 935 #endif
 936 }
 937
 938 /*
 939  * this is only called if !populated_zone(zone), which implies no other users of
 940  * pset->vm_stat_diff[] exist.
 941  */
 942 void drain_zonestat(struct zone *zone, struct per_cpu_zonestat *pzstats)
 943 {
 944         int i;
 945
 946         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 947                 if (pzstats->vm_stat_diff[i]) {
 948                         int v = pzstats->vm_stat_diff[i];
 949                         pzstats->vm_stat_diff[i] = 0;
 950                         atomic_long_add(v, &zone->vm_stat[i]);
 951                         atomic_long_add(v, &vm_zone_stat[i]);
 952                 }
 953
 954 #ifdef CONFIG_NUMA
 955         for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
 956                 if (pzstats->vm_numa_stat_diff[i]) {
 957                         int v = pzstats->vm_numa_stat_diff[i];
 958
 959                         pzstats->vm_numa_stat_diff[i] = 0;
 960                         atomic_long_add(v, &zone->vm_numa_stat[i]);
 961                         atomic_long_add(v, &vm_numa_stat[i]);
 962                 }
 963 #endif
 964 }
 965 #endif
 966
 967 #ifdef CONFIG_NUMA
 968 void __inc_numa_state(struct zone *zone,
 969                                  enum numa_stat_item item)
 970 {
 971         struct per_cpu_zonestat __percpu *pzstats = zone->per_cpu_zonestats;
 972         u16 __percpu *p = pzstats->vm_numa_stat_diff + item;
 973         u16 v;
 974
 975         v = __this_cpu_inc_return(*p);
 976
 977         if (unlikely(v > NUMA_STATS_THRESHOLD)) {
 978                 zone_numa_state_add(v, zone, item);
 979                 __this_cpu_write(*p, 0);
 980         }
 981 }
 982
 983 /*
 984  * Determine the per node value of a stat item. This function
 985  * is called frequently in a NUMA machine, so try to be as
 986  * frugal as possible.
 987  */
 988 unsigned long sum_zone_node_page_state(int node,
 989                                  enum zone_stat_item item)
 990 {
 991         struct zone *zones = NODE_DATA(node)->node_zones;
 992         int i;
 993         unsigned long count = 0;
 994
 995         for (i = 0; i < MAX_NR_ZONES; i++)
 996                 count += zone_page_state(zones + i, item);
 997
 998         return count;
 999 }
1000
1001 /*
1002  * Determine the per node value of a numa stat item. To avoid deviation,
1003  * the per cpu stat number in vm_numa_stat_diff[] is also included.
1004  */
1005 unsigned long sum_zone_numa_state(int node,
1006                                  enum numa_stat_item item)
1007 {
1008         struct zone *zones = NODE_DATA(node)->node_zones;
1009         int i;
1010         unsigned long count = 0;
1011
1012         for (i = 0; i < MAX_NR_ZONES; i++)
1013                 count += zone_numa_state_snapshot(zones + i, item);
1014
1015         return count;
1016 }
1017
1018 /*
1019  * Determine the per node value of a stat item.
1020  */
1021 unsigned long node_page_state_pages(struct pglist_data *pgdat,
1022                                     enum node_stat_item item)
1023 {
1024         long x = atomic_long_read(&pgdat->vm_stat[item]);
1025 #ifdef CONFIG_SMP
1026         if (x < 0)
1027                 x = 0;
1028 #endif
1029         return x;
1030 }
1031
1032 unsigned long node_page_state(struct pglist_data *pgdat,
1033                               enum node_stat_item item)
1034 {
1035         VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
1036
1037         return node_page_state_pages(pgdat, item);
1038 }
1039 #endif
1040
1041 #ifdef CONFIG_COMPACTION
1042
1043 struct contig_page_info {
1044         unsigned long free_pages;
1045         unsigned long free_blocks_total;
1046         unsigned long free_blocks_suitable;
1047 };
1048
1049 /*
1050  * Calculate the number of free pages in a zone, how many contiguous
1051  * pages are free and how many are large enough to satisfy an allocation of
1052  * the target size. Note that this function makes no attempt to estimate
1053  * how many suitable free blocks there *might* be if MOVABLE pages were
1054  * migrated. Calculating that is possible, but expensive and can be
1055  * figured out from userspace
1056  */
1057 static void fill_contig_page_info(struct zone *zone,
1058                                 unsigned int suitable_order,
1059                                 struct contig_page_info *info)
1060 {
1061         unsigned int order;
1062
1063         info->free_pages = 0;
1064         info->free_blocks_total = 0;
1065         info->free_blocks_suitable = 0;
1066
1067         for (order = 0; order < MAX_ORDER; order++) {
1068                 unsigned long blocks;
1069
1070                 /* Count number of free blocks */
1071                 blocks = zone->free_area[order].nr_free;
1072                 info->free_blocks_total += blocks;
1073
1074                 /* Count free base pages */
1075                 info->free_pages += blocks << order;
1076
1077                 /* Count the suitable free blocks */
1078                 if (order >= suitable_order)
1079                         info->free_blocks_suitable += blocks <<
1080                                                 (order - suitable_order);
1081         }
1082 }
1083
1084 /*
1085  * A fragmentation index only makes sense if an allocation of a requested
1086  * size would fail. If that is true, the fragmentation index indicates
1087  * whether external fragmentation or a lack of memory was the problem.
1088  * The value can be used to determine if page reclaim or compaction
1089  * should be used
1090  */
1091 static int __fragmentation_index(unsigned int order, struct contig_page_info *info)
1092 {
1093         unsigned long requested = 1UL << order;
1094
1095         if (WARN_ON_ONCE(order >= MAX_ORDER))
1096                 return 0;
1097
1098         if (!info->free_blocks_total)
1099                 return 0;
1100
1101         /* Fragmentation index only makes sense when a request would fail */
1102         if (info->free_blocks_suitable)
1103                 return -1000;
1104
1105         /*
1106          * Index is between 0 and 1 so return within 3 decimal places
1107          *
1108          * 0 => allocation would fail due to lack of memory
1109          * 1 => allocation would fail due to fragmentation
1110          */
1111         return 1000 - div_u64( (1000+(div_u64(info->free_pages * 1000ULL, requested))), info->free_blocks_total);
1112 }
1113
1114 /*
1115  * Calculates external fragmentation within a zone wrt the given order.
1116  * It is defined as the percentage of pages found in blocks of size
1117  * less than 1 << order. It returns values in range [0, 100].
1118  */
1119 unsigned int extfrag_for_order(struct zone *zone, unsigned int order)
1120 {
1121         struct contig_page_info info;
1122
1123         fill_contig_page_info(zone, order, &info);
1124         if (info.free_pages == 0)
1125                 return 0;
1126
1127         return div_u64((info.free_pages -
1128                         (info.free_blocks_suitable << order)) * 100,
1129                         info.free_pages);
1130 }
1131
1132 /* Same as __fragmentation index but allocs contig_page_info on stack */
1133 int fragmentation_index(struct zone *zone, unsigned int order)
1134 {
1135         struct contig_page_info info;
1136
1137         fill_contig_page_info(zone, order, &info);
1138         return __fragmentation_index(order, &info);
1139 }
1140 #endif
1141
1142 #if defined(CONFIG_PROC_FS) || defined(CONFIG_SYSFS) || \
1143     defined(CONFIG_NUMA) || defined(CONFIG_MEMCG)
1144 #ifdef CONFIG_ZONE_DMA
1145 #define TEXT_FOR_DMA(xx) xx "_dma",
1146 #else
1147 #define TEXT_FOR_DMA(xx)
1148 #endif
1149
1150 #ifdef CONFIG_ZONE_DMA32
1151 #define TEXT_FOR_DMA32(xx) xx "_dma32",
1152 #else
1153 #define TEXT_FOR_DMA32(xx)
1154 #endif
1155
1156 #ifdef CONFIG_HIGHMEM
1157 #define TEXT_FOR_HIGHMEM(xx) xx "_high",
1158 #else
1159 #define TEXT_FOR_HIGHMEM(xx)
1160 #endif
1161
1162 #define TEXTS_FOR_ZONES(xx) TEXT_FOR_DMA(xx) TEXT_FOR_DMA32(xx) xx "_normal", \
1163                                         TEXT_FOR_HIGHMEM(xx) xx "_movable",
1164
1165 const char * const vmstat_text[] = {
1166         /* enum zone_stat_item counters */
1167         "nr_free_pages",
1168         "nr_zone_inactive_anon",
1169         "nr_zone_active_anon",
1170         "nr_zone_inactive_file",
1171         "nr_zone_active_file",
1172         "nr_zone_unevictable",
1173         "nr_zone_write_pending",
1174         "nr_mlock",
1175         "nr_bounce",
1176 #if IS_ENABLED(CONFIG_ZSMALLOC)
1177         "nr_zspages",
1178 #endif
1179         "nr_free_cma",
1180
1181         /* enum numa_stat_item counters */
1182 #ifdef CONFIG_NUMA
1183         "numa_hit",
1184         "numa_miss",
1185         "numa_foreign",
1186         "numa_interleave",
1187         "numa_local",
1188         "numa_other",
1189 #endif
1190
1191         /* enum node_stat_item counters */
1192         "nr_inactive_anon",
1193         "nr_active_anon",
1194         "nr_inactive_file",
1195         "nr_active_file",
1196         "nr_unevictable",
1197         "nr_slab_reclaimable",
1198         "nr_slab_unreclaimable",
1199         "nr_isolated_anon",
1200         "nr_isolated_file",
1201         "workingset_nodes",
1202         "workingset_refault_anon",
1203         "workingset_refault_file",
1204         "workingset_activate_anon",
1205         "workingset_activate_file",
1206         "workingset_restore_anon",
1207         "workingset_restore_file",
1208         "workingset_nodereclaim",
1209         "nr_anon_pages",
1210         "nr_mapped",
1211         "nr_file_pages",
1212         "nr_dirty",
1213         "nr_writeback",
1214         "nr_writeback_temp",
1215         "nr_shmem",
1216         "nr_shmem_hugepages",
1217         "nr_shmem_pmdmapped",
1218         "nr_file_hugepages",
1219         "nr_file_pmdmapped",
1220         "nr_anon_transparent_hugepages",
1221         "nr_vmscan_write",
1222         "nr_vmscan_immediate_reclaim",
1223         "nr_dirtied",
1224         "nr_written",
1225         "nr_kernel_misc_reclaimable",
1226         "nr_foll_pin_acquired",
1227         "nr_foll_pin_released",
1228         "nr_kernel_stack",
1229 #if IS_ENABLED(CONFIG_SHADOW_CALL_STACK)
1230         "nr_shadow_call_stack",
1231 #endif
1232         "nr_page_table_pages",
1233 #ifdef CONFIG_SWAP
1234         "nr_swapcached",
1235 #endif
1236
1237         /* enum writeback_stat_item counters */
1238         "nr_dirty_threshold",
1239         "nr_dirty_background_threshold",
1240
1241 #if defined(CONFIG_VM_EVENT_COUNTERS) || defined(CONFIG_MEMCG)
1242         /* enum vm_event_item counters */
1243         "pgpgin",
1244         "pgpgout",
1245         "pswpin",
1246         "pswpout",
1247
1248         TEXTS_FOR_ZONES("pgalloc")
1249         TEXTS_FOR_ZONES("allocstall")
1250         TEXTS_FOR_ZONES("pgskip")
1251
1252         "pgfree",
1253         "pgactivate",
1254         "pgdeactivate",
1255         "pglazyfree",
1256
1257         "pgfault",
1258         "pgmajfault",
1259         "pglazyfreed",
1260
1261         "pgrefill",
1262         "pgreuse",
1263         "pgsteal_kswapd",
1264         "pgsteal_direct",
1265         "pgscan_kswapd",
1266         "pgscan_direct",
1267         "pgscan_direct_throttle",
1268         "pgscan_anon",
1269         "pgscan_file",
1270         "pgsteal_anon",
1271         "pgsteal_file",
1272
1273 #ifdef CONFIG_NUMA
1274         "zone_reclaim_failed",
1275 #endif
1276         "pginodesteal",
1277         "slabs_scanned",
1278         "kswapd_inodesteal",
1279         "kswapd_low_wmark_hit_quickly",
1280         "kswapd_high_wmark_hit_quickly",
1281         "pageoutrun",
1282
1283         "pgrotated",
1284
1285         "drop_pagecache",
1286         "drop_slab",
1287         "oom_kill",
1288
1289 #ifdef CONFIG_NUMA_BALANCING
1290         "numa_pte_updates",
1291         "numa_huge_pte_updates",
1292         "numa_hint_faults",
1293         "numa_hint_faults_local",
1294         "numa_pages_migrated",
1295 #endif
1296 #ifdef CONFIG_MIGRATION
1297         "pgmigrate_success",
1298         "pgmigrate_fail",
1299         "thp_migration_success",
1300         "thp_migration_fail",
1301         "thp_migration_split",
1302 #endif
1303 #ifdef CONFIG_COMPACTION
1304         "compact_migrate_scanned",
1305         "compact_free_scanned",
1306         "compact_isolated",
1307         "compact_stall",
1308         "compact_fail",
1309         "compact_success",
1310         "compact_daemon_wake",
1311         "compact_daemon_migrate_scanned",
1312         "compact_daemon_free_scanned",
1313 #endif
1314
1315 #ifdef CONFIG_HUGETLB_PAGE
1316         "htlb_buddy_alloc_success",
1317         "htlb_buddy_alloc_fail",
1318 #endif
1319 #ifdef CONFIG_CMA
1320         "cma_alloc_success",
1321         "cma_alloc_fail",
1322 #endif
1323         "unevictable_pgs_culled",
1324         "unevictable_pgs_scanned",
1325         "unevictable_pgs_rescued",
1326         "unevictable_pgs_mlocked",
1327         "unevictable_pgs_munlocked",
1328         "unevictable_pgs_cleared",
1329         "unevictable_pgs_stranded",
1330
1331 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1332         "thp_fault_alloc",
1333         "thp_fault_fallback",
1334         "thp_fault_fallback_charge",
1335         "thp_collapse_alloc",
1336         "thp_collapse_alloc_failed",
1337         "thp_file_alloc",
1338         "thp_file_fallback",
1339         "thp_file_fallback_charge",
1340         "thp_file_mapped",
1341         "thp_split_page",
1342         "thp_split_page_failed",
1343         "thp_deferred_split_page",
1344         "thp_split_pmd",
1345 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
1346         "thp_split_pud",
1347 #endif
1348         "thp_zero_page_alloc",
1349         "thp_zero_page_alloc_failed",
1350         "thp_swpout",
1351         "thp_swpout_fallback",
1352 #endif
1353 #ifdef CONFIG_MEMORY_BALLOON
1354         "balloon_inflate",
1355         "balloon_deflate",
1356 #ifdef CONFIG_BALLOON_COMPACTION
1357         "balloon_migrate",
1358 #endif
1359 #endif /* CONFIG_MEMORY_BALLOON */
1360 #ifdef CONFIG_DEBUG_TLBFLUSH
1361         "nr_tlb_remote_flush",
1362         "nr_tlb_remote_flush_received",
1363         "nr_tlb_local_flush_all",
1364         "nr_tlb_local_flush_one",
1365 #endif /* CONFIG_DEBUG_TLBFLUSH */
1366
1367 #ifdef CONFIG_DEBUG_VM_VMACACHE
1368         "vmacache_find_calls",
1369         "vmacache_find_hits",
1370 #endif
1371 #ifdef CONFIG_SWAP
1372         "swap_ra",
1373         "swap_ra_hit",
1374 #endif
1375 #ifdef CONFIG_X86
1376         "direct_map_level2_splits",
1377         "direct_map_level3_splits",
1378 #endif
1379 #endif /* CONFIG_VM_EVENT_COUNTERS || CONFIG_MEMCG */
1380 };
1381 #endif /* CONFIG_PROC_FS || CONFIG_SYSFS || CONFIG_NUMA || CONFIG_MEMCG */
1382
1383 #if (defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)) || \
1384      defined(CONFIG_PROC_FS)
1385 static void *frag_start(struct seq_file *m, loff_t *pos)
1386 {
1387         pg_data_t *pgdat;
1388         loff_t node = *pos;
1389
1390         for (pgdat = first_online_pgdat();
1391              pgdat && node;
1392              pgdat = next_online_pgdat(pgdat))
1393                 --node;
1394
1395         return pgdat;
1396 }
1397
1398 static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
1399 {
1400         pg_data_t *pgdat = (pg_data_t *)arg;
1401
1402         (*pos)++;
1403         return next_online_pgdat(pgdat);
1404 }
1405
1406 static void frag_stop(struct seq_file *m, void *arg)
1407 {
1408 }
1409
1410 /*
1411  * Walk zones in a node and print using a callback.
1412  * If @assert_populated is true, only use callback for zones that are populated.
1413  */
1414 static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat,
1415                 bool assert_populated, bool nolock,
1416                 void (*print)(struct seq_file *m, pg_data_t *, struct zone *))
1417 {
1418         struct zone *zone;
1419         struct zone *node_zones = pgdat->node_zones;
1420         unsigned long flags;
1421
1422         for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
1423                 if (assert_populated && !populated_zone(zone))
1424                         continue;
1425
1426                 if (!nolock)
1427                         spin_lock_irqsave(&zone->lock, flags);
1428                 print(m, pgdat, zone);
1429                 if (!nolock)
1430                         spin_unlock_irqrestore(&zone->lock, flags);
1431         }
1432 }
1433 #endif
1434
1435 #ifdef CONFIG_PROC_FS
1436 static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,
1437                                                 struct zone *zone)
1438 {
1439         int order;
1440
1441         seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
1442         for (order = 0; order < MAX_ORDER; ++order)
1443                 seq_printf(m, "%6lu ", zone->free_area[order].nr_free);
1444         seq_putc(m, '\n');
1445 }
1446
1447 /*
1448  * This walks the free areas for each zone.
1449  */
1450 static int frag_show(struct seq_file *m, void *arg)
1451 {
1452         pg_data_t *pgdat = (pg_data_t *)arg;
1453         walk_zones_in_node(m, pgdat, true, false, frag_show_print);
1454         return 0;
1455 }
1456
1457 static void pagetypeinfo_showfree_print(struct seq_file *m,
1458                                         pg_data_t *pgdat, struct zone *zone)
1459 {
1460         int order, mtype;
1461
1462         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++) {
1463                 seq_printf(m, "Node %4d, zone %8s, type %12s ",
1464                                         pgdat->node_id,
1465                                         zone->name,
1466                                         migratetype_names[mtype]);
1467                 for (order = 0; order < MAX_ORDER; ++order) {
1468                         unsigned long freecount = 0;
1469                         struct free_area *area;
1470                         struct list_head *curr;
1471                         bool overflow = false;
1472
1473                         area = &(zone->free_area[order]);
1474
1475                         list_for_each(curr, &area->free_list[mtype]) {
1476                                 /*
1477                                  * Cap the free_list iteration because it might
1478                                  * be really large and we are under a spinlock
1479                                  * so a long time spent here could trigger a
1480                                  * hard lockup detector. Anyway this is a
1481                                  * debugging tool so knowing there is a handful
1482                                  * of pages of this order should be more than
1483                                  * sufficient.
1484                                  */
1485                                 if (++freecount >= 100000) {
1486                                         overflow = true;
1487                                         break;
1488                                 }
1489                         }
1490                         seq_printf(m, "%s%6lu ", overflow ? ">" : "", freecount);
1491                         spin_unlock_irq(&zone->lock);
1492                         cond_resched();
1493                         spin_lock_irq(&zone->lock);
1494                 }
1495                 seq_putc(m, '\n');
1496         }
1497 }
1498
1499 /* Print out the free pages at each order for each migatetype */
1500 static int pagetypeinfo_showfree(struct seq_file *m, void *arg)
1501 {
1502         int order;
1503         pg_data_t *pgdat = (pg_data_t *)arg;
1504
1505         /* Print header */
1506         seq_printf(m, "%-43s ", "Free pages count per migrate type at order");
1507         for (order = 0; order < MAX_ORDER; ++order)
1508                 seq_printf(m, "%6d ", order);
1509         seq_putc(m, '\n');
1510
1511         walk_zones_in_node(m, pgdat, true, false, pagetypeinfo_showfree_print);
1512
1513         return 0;
1514 }
1515
1516 static void pagetypeinfo_showblockcount_print(struct seq_file *m,
1517                                         pg_data_t *pgdat, struct zone *zone)
1518 {
1519         int mtype;
1520         unsigned long pfn;
1521         unsigned long start_pfn = zone->zone_start_pfn;
1522         unsigned long end_pfn = zone_end_pfn(zone);
1523         unsigned long count[MIGRATE_TYPES] = { 0, };
1524
1525         for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
1526                 struct page *page;
1527
1528                 page = pfn_to_online_page(pfn);
1529                 if (!page)
1530                         continue;
1531
1532                 if (page_zone(page) != zone)
1533                         continue;
1534
1535                 mtype = get_pageblock_migratetype(page);
1536
1537                 if (mtype < MIGRATE_TYPES)
1538                         count[mtype]++;
1539         }
1540
1541         /* Print counts */
1542         seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
1543         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
1544                 seq_printf(m, "%12lu ", count[mtype]);
1545         seq_putc(m, '\n');
1546 }
1547
1548 /* Print out the number of pageblocks for each migratetype */
1549 static int pagetypeinfo_showblockcount(struct seq_file *m, void *arg)
1550 {
1551         int mtype;
1552         pg_data_t *pgdat = (pg_data_t *)arg;
1553
1554         seq_printf(m, "\n%-23s", "Number of blocks type ");
1555         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
1556                 seq_printf(m, "%12s ", migratetype_names[mtype]);
1557         seq_putc(m, '\n');
1558         walk_zones_in_node(m, pgdat, true, false,
1559                 pagetypeinfo_showblockcount_print);
1560
1561         return 0;
1562 }
1563
1564 /*
1565  * Print out the number of pageblocks for each migratetype that contain pages
1566  * of other types. This gives an indication of how well fallbacks are being
1567  * contained by rmqueue_fallback(). It requires information from PAGE_OWNER
1568  * to determine what is going on
1569  */
1570 static void pagetypeinfo_showmixedcount(struct seq_file *m, pg_data_t *pgdat)
1571 {
1572 #ifdef CONFIG_PAGE_OWNER
1573         int mtype;
1574
1575         if (!static_branch_unlikely(&page_owner_inited))
1576                 return;
1577
1578         drain_all_pages(NULL);
1579
1580         seq_printf(m, "\n%-23s", "Number of mixed blocks ");
1581         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
1582                 seq_printf(m, "%12s ", migratetype_names[mtype]);
1583         seq_putc(m, '\n');
1584
1585         walk_zones_in_node(m, pgdat, true, true,
1586                 pagetypeinfo_showmixedcount_print);
1587 #endif /* CONFIG_PAGE_OWNER */
1588 }
1589
1590 /*
1591  * This prints out statistics in relation to grouping pages by mobility.
1592  * It is expensive to collect so do not constantly read the file.
1593  */
1594 static int pagetypeinfo_show(struct seq_file *m, void *arg)
1595 {
1596         pg_data_t *pgdat = (pg_data_t *)arg;
1597
1598         /* check memoryless node */
1599         if (!node_state(pgdat->node_id, N_MEMORY))
1600                 return 0;
1601
1602         seq_printf(m, "Page block order: %d\n", pageblock_order);
1603         seq_printf(m, "Pages per block:  %lu\n", pageblock_nr_pages);
1604         seq_putc(m, '\n');
1605         pagetypeinfo_showfree(m, pgdat);
1606         pagetypeinfo_showblockcount(m, pgdat);
1607         pagetypeinfo_showmixedcount(m, pgdat);
1608
1609         return 0;
1610 }
1611
1612 static const struct seq_operations fragmentation_op = {
1613         .start  = frag_start,
1614         .next   = frag_next,
1615         .stop   = frag_stop,
1616         .show   = frag_show,
1617 };
1618
1619 static const struct seq_operations pagetypeinfo_op = {
1620         .start  = frag_start,
1621         .next   = frag_next,
1622         .stop   = frag_stop,
1623         .show   = pagetypeinfo_show,
1624 };
1625
1626 static bool is_zone_first_populated(pg_data_t *pgdat, struct zone *zone)
1627 {
1628         int zid;
1629
1630         for (zid = 0; zid < MAX_NR_ZONES; zid++) {
1631                 struct zone *compare = &pgdat->node_zones[zid];
1632
1633                 if (populated_zone(compare))
1634                         return zone == compare;
1635         }
1636
1637         return false;
1638 }
1639
1640 static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
1641                                                         struct zone *zone)
1642 {
1643         int i;
1644         seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name);
1645         if (is_zone_first_populated(pgdat, zone)) {
1646                 seq_printf(m, "\n  per-node stats");
1647                 for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
1648                         unsigned long pages = node_page_state_pages(pgdat, i);
1649
1650                         if (vmstat_item_print_in_thp(i))
1651                                 pages /= HPAGE_PMD_NR;
1652                         seq_printf(m, "\n      %-12s %lu", node_stat_name(i),
1653                                    pages);
1654                 }
1655         }
1656         seq_printf(m,
1657                    "\n  pages free     %lu"
1658                    "\n        min      %lu"
1659                    "\n        low      %lu"
1660                    "\n        high     %lu"
1661                    "\n        spanned  %lu"
1662                    "\n        present  %lu"
1663                    "\n        managed  %lu"
1664                    "\n        cma      %lu",
1665                    zone_page_state(zone, NR_FREE_PAGES),
1666                    min_wmark_pages(zone),
1667                    low_wmark_pages(zone),
1668                    high_wmark_pages(zone),
1669                    zone->spanned_pages,
1670                    zone->present_pages,
1671                    zone_managed_pages(zone),
1672                    zone_cma_pages(zone));
1673
1674         seq_printf(m,
1675                    "\n        protection: (%ld",
1676                    zone->lowmem_reserve[0]);
1677         for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++)
1678                 seq_printf(m, ", %ld", zone->lowmem_reserve[i]);
1679         seq_putc(m, ')');
1680
1681         /* If unpopulated, no other information is useful */
1682         if (!populated_zone(zone)) {
1683                 seq_putc(m, '\n');
1684                 return;
1685         }
1686
1687         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
1688                 seq_printf(m, "\n      %-12s %lu", zone_stat_name(i),
1689                            zone_page_state(zone, i));
1690
1691 #ifdef CONFIG_NUMA
1692         for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
1693                 seq_printf(m, "\n      %-12s %lu", numa_stat_name(i),
1694                            zone_numa_state_snapshot(zone, i));
1695 #endif
1696
1697         seq_printf(m, "\n  pagesets");
1698         for_each_online_cpu(i) {
1699                 struct per_cpu_pages *pcp;
1700                 struct per_cpu_zonestat __maybe_unused *pzstats;
1701
1702                 pcp = per_cpu_ptr(zone->per_cpu_pageset, i);
1703                 seq_printf(m,
1704                            "\n    cpu: %i"
1705                            "\n              count: %i"
1706                            "\n              high:  %i"
1707                            "\n              batch: %i",
1708                            i,
1709                            pcp->count,
1710                            pcp->high,
1711                            pcp->batch);
1712 #ifdef CONFIG_SMP
1713                 pzstats = per_cpu_ptr(zone->per_cpu_zonestats, i);
1714                 seq_printf(m, "\n  vm stats threshold: %d",
1715                                 pzstats->stat_threshold);
1716 #endif
1717         }
1718         seq_printf(m,
1719                    "\n  node_unreclaimable:  %u"
1720                    "\n  start_pfn:           %lu",
1721                    pgdat->kswapd_failures >= MAX_RECLAIM_RETRIES,
1722                    zone->zone_start_pfn);
1723         seq_putc(m, '\n');
1724 }
1725
1726 /*
1727  * Output information about zones in @pgdat.  All zones are printed regardless
1728  * of whether they are populated or not: lowmem_reserve_ratio operates on the
1729  * set of all zones and userspace would not be aware of such zones if they are
1730  * suppressed here (zoneinfo displays the effect of lowmem_reserve_ratio).
1731  */
1732 static int zoneinfo_show(struct seq_file *m, void *arg)
1733 {
1734         pg_data_t *pgdat = (pg_data_t *)arg;
1735         walk_zones_in_node(m, pgdat, false, false, zoneinfo_show_print);
1736         return 0;
1737 }
1738
1739 static const struct seq_operations zoneinfo_op = {
1740         .start  = frag_start, /* iterate over all zones. The same as in
1741                                * fragmentation. */
1742         .next   = frag_next,
1743         .stop   = frag_stop,
1744         .show   = zoneinfo_show,
1745 };
1746
1747 #define NR_VMSTAT_ITEMS (NR_VM_ZONE_STAT_ITEMS + \
1748                          NR_VM_NUMA_STAT_ITEMS + \
1749                          NR_VM_NODE_STAT_ITEMS + \
1750                          NR_VM_WRITEBACK_STAT_ITEMS + \
1751                          (IS_ENABLED(CONFIG_VM_EVENT_COUNTERS) ? \
1752                           NR_VM_EVENT_ITEMS : 0))
1753
1754 static void *vmstat_start(struct seq_file *m, loff_t *pos)
1755 {
1756         unsigned long *v;
1757         int i;
1758
1759         if (*pos >= NR_VMSTAT_ITEMS)
1760                 return NULL;
1761
1762         BUILD_BUG_ON(ARRAY_SIZE(vmstat_text) < NR_VMSTAT_ITEMS);
1763         v = kmalloc_array(NR_VMSTAT_ITEMS, sizeof(unsigned long), GFP_KERNEL);
1764         m->private = v;
1765         if (!v)
1766                 return ERR_PTR(-ENOMEM);
1767         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
1768                 v[i] = global_zone_page_state(i);
1769         v += NR_VM_ZONE_STAT_ITEMS;
1770
1771 #ifdef CONFIG_NUMA
1772         for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
1773                 v[i] = global_numa_state(i);
1774         v += NR_VM_NUMA_STAT_ITEMS;
1775 #endif
1776
1777         for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
1778                 v[i] = global_node_page_state_pages(i);
1779                 if (vmstat_item_print_in_thp(i))
1780                         v[i] /= HPAGE_PMD_NR;
1781         }
1782         v += NR_VM_NODE_STAT_ITEMS;
1783
1784         global_dirty_limits(v + NR_DIRTY_BG_THRESHOLD,
1785                             v + NR_DIRTY_THRESHOLD);
1786         v += NR_VM_WRITEBACK_STAT_ITEMS;
1787
1788 #ifdef CONFIG_VM_EVENT_COUNTERS
1789         all_vm_events(v);
1790         v[PGPGIN] /= 2;         /* sectors -> kbytes */
1791         v[PGPGOUT] /= 2;
1792 #endif
1793         return (unsigned long *)m->private + *pos;
1794 }
1795
1796 static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)
1797 {
1798         (*pos)++;
1799         if (*pos >= NR_VMSTAT_ITEMS)
1800                 return NULL;
1801         return (unsigned long *)m->private + *pos;
1802 }
1803
1804 static int vmstat_show(struct seq_file *m, void *arg)
1805 {
1806         unsigned long *l = arg;
1807         unsigned long off = l - (unsigned long *)m->private;
1808
1809         seq_puts(m, vmstat_text[off]);
1810         seq_put_decimal_ull(m, " ", *l);
1811         seq_putc(m, '\n');
1812
1813         if (off == NR_VMSTAT_ITEMS - 1) {
1814                 /*
1815                  * We've come to the end - add any deprecated counters to avoid
1816                  * breaking userspace which might depend on them being present.
1817                  */
1818                 seq_puts(m, "nr_unstable 0\n");
1819         }
1820         return 0;
1821 }
1822
1823 static void vmstat_stop(struct seq_file *m, void *arg)
1824 {
1825         kfree(m->private);
1826         m->private = NULL;
1827 }
1828
1829 static const struct seq_operations vmstat_op = {
1830         .start  = vmstat_start,
1831         .next   = vmstat_next,
1832         .stop   = vmstat_stop,
1833         .show   = vmstat_show,
1834 };
1835 #endif /* CONFIG_PROC_FS */
1836
1837 #ifdef CONFIG_SMP
1838 static DEFINE_PER_CPU(struct delayed_work, vmstat_work);
1839 int sysctl_stat_interval __read_mostly = HZ;
1840
1841 #ifdef CONFIG_PROC_FS
1842 static void refresh_vm_stats(struct work_struct *work)
1843 {
1844         refresh_cpu_vm_stats(true);
1845 }
1846
1847 int vmstat_refresh(struct ctl_table *table, int write,
1848                    void *buffer, size_t *lenp, loff_t *ppos)
1849 {
1850         long val;
1851         int err;
1852         int i;
1853
1854         /*
1855          * The regular update, every sysctl_stat_interval, may come later
1856          * than expected: leaving a significant amount in per_cpu buckets.
1857          * This is particularly misleading when checking a quantity of HUGE
1858          * pages, immediately after running a test.  /proc/sys/vm/stat_refresh,
1859          * which can equally be echo'ed to or cat'ted from (by root),
1860          * can be used to update the stats just before reading them.
1861          *
1862          * Oh, and since global_zone_page_state() etc. are so careful to hide
1863          * transiently negative values, report an error here if any of
1864          * the stats is negative, so we know to go looking for imbalance.
1865          */
1866         err = schedule_on_each_cpu(refresh_vm_stats);
1867         if (err)
1868                 return err;
1869         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
1870                 /*
1871                  * Skip checking stats known to go negative occasionally.
1872                  */
1873                 switch (i) {
1874                 case NR_ZONE_WRITE_PENDING:
1875                 case NR_FREE_CMA_PAGES:
1876                         continue;
1877                 }
1878                 val = atomic_long_read(&vm_zone_stat[i]);
1879                 if (val < 0) {
1880                         pr_warn("%s: %s %ld\n",
1881                                 __func__, zone_stat_name(i), val);
1882                 }
1883         }
1884         for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
1885                 /*
1886                  * Skip checking stats known to go negative occasionally.
1887                  */
1888                 switch (i) {
1889                 case NR_WRITEBACK:
1890                         continue;
1891                 }
1892                 val = atomic_long_read(&vm_node_stat[i]);
1893                 if (val < 0) {
1894                         pr_warn("%s: %s %ld\n",
1895                                 __func__, node_stat_name(i), val);
1896                 }
1897         }
1898         if (write)
1899                 *ppos += *lenp;
1900         else
1901                 *lenp = 0;
1902         return 0;
1903 }
1904 #endif /* CONFIG_PROC_FS */
1905
1906 static void vmstat_update(struct work_struct *w)
1907 {
1908         if (refresh_cpu_vm_stats(true)) {
1909                 /*
1910                  * Counters were updated so we expect more updates
1911                  * to occur in the future. Keep on running the
1912                  * update worker thread.
1913                  */
1914                 queue_delayed_work_on(smp_processor_id(), mm_percpu_wq,
1915                                 this_cpu_ptr(&vmstat_work),
1916                                 round_jiffies_relative(sysctl_stat_interval));
1917         }
1918 }
1919
1920 /*
1921  * Switch off vmstat processing and then fold all the remaining differentials
1922  * until the diffs stay at zero. The function is used by NOHZ and can only be
1923  * invoked when tick processing is not active.
1924  */
1925 /*
1926  * Check if the diffs for a certain cpu indicate that
1927  * an update is needed.
1928  */
1929 static bool need_update(int cpu)
1930 {
1931         pg_data_t *last_pgdat = NULL;
1932         struct zone *zone;
1933
1934         for_each_populated_zone(zone) {
1935                 struct per_cpu_zonestat *pzstats = per_cpu_ptr(zone->per_cpu_zonestats, cpu);
1936                 struct per_cpu_nodestat *n;
1937
1938                 /*
1939                  * The fast way of checking if there are any vmstat diffs.
1940                  */
1941                 if (memchr_inv(pzstats->vm_stat_diff, 0, NR_VM_ZONE_STAT_ITEMS *
1942                                sizeof(pzstats->vm_stat_diff[0])))
1943                         return true;
1944 #ifdef CONFIG_NUMA
1945                 if (memchr_inv(pzstats->vm_numa_stat_diff, 0, NR_VM_NUMA_STAT_ITEMS *
1946                                sizeof(pzstats->vm_numa_stat_diff[0])))
1947                         return true;
1948 #endif
1949                 if (last_pgdat == zone->zone_pgdat)
1950                         continue;
1951                 last_pgdat = zone->zone_pgdat;
1952                 n = per_cpu_ptr(zone->zone_pgdat->per_cpu_nodestats, cpu);
1953                 if (memchr_inv(n->vm_node_stat_diff, 0, NR_VM_NODE_STAT_ITEMS *
1954                                sizeof(n->vm_node_stat_diff[0])))
1955                     return true;
1956         }
1957         return false;
1958 }
1959
1960 /*
1961  * Switch off vmstat processing and then fold all the remaining differentials
1962  * until the diffs stay at zero. The function is used by NOHZ and can only be
1963  * invoked when tick processing is not active.
1964  */
1965 void quiet_vmstat(void)
1966 {
1967         if (system_state != SYSTEM_RUNNING)
1968                 return;
1969
1970         if (!delayed_work_pending(this_cpu_ptr(&vmstat_work)))
1971                 return;
1972
1973         if (!need_update(smp_processor_id()))
1974                 return;
1975
1976         /*
1977          * Just refresh counters and do not care about the pending delayed
1978          * vmstat_update. It doesn't fire that often to matter and canceling
1979          * it would be too expensive from this path.
1980          * vmstat_shepherd will take care about that for us.
1981          */
1982         refresh_cpu_vm_stats(false);
1983 }
1984
1985 /*
1986  * Shepherd worker thread that checks the
1987  * differentials of processors that have their worker
1988  * threads for vm statistics updates disabled because of
1989  * inactivity.
1990  */
1991 static void vmstat_shepherd(struct work_struct *w);
1992
1993 static DECLARE_DEFERRABLE_WORK(shepherd, vmstat_shepherd);
1994
1995 static void vmstat_shepherd(struct work_struct *w)
1996 {
1997         int cpu;
1998
1999         get_online_cpus();
2000         /* Check processors whose vmstat worker threads have been disabled */
2001         for_each_online_cpu(cpu) {
2002                 struct delayed_work *dw = &per_cpu(vmstat_work, cpu);
2003
2004                 if (!delayed_work_pending(dw) && need_update(cpu))
2005                         queue_delayed_work_on(cpu, mm_percpu_wq, dw, 0);
2006
2007                 cond_resched();
2008         }
2009         put_online_cpus();
2010
2011         schedule_delayed_work(&shepherd,
2012                 round_jiffies_relative(sysctl_stat_interval));
2013 }
2014
2015 static void __init start_shepherd_timer(void)
2016 {
2017         int cpu;
2018
2019         for_each_possible_cpu(cpu)
2020                 INIT_DEFERRABLE_WORK(per_cpu_ptr(&vmstat_work, cpu),
2021                         vmstat_update);
2022
2023         schedule_delayed_work(&shepherd,
2024                 round_jiffies_relative(sysctl_stat_interval));
2025 }
2026
2027 static void __init init_cpu_node_state(void)
2028 {
2029         int node;
2030
2031         for_each_online_node(node) {
2032                 if (cpumask_weight(cpumask_of_node(node)) > 0)
2033                         node_set_state(node, N_CPU);
2034         }
2035 }
2036
2037 static int vmstat_cpu_online(unsigned int cpu)
2038 {
2039         refresh_zone_stat_thresholds();
2040         node_set_state(cpu_to_node(cpu), N_CPU);
2041         return 0;
2042 }
2043
2044 static int vmstat_cpu_down_prep(unsigned int cpu)
2045 {
2046         cancel_delayed_work_sync(&per_cpu(vmstat_work, cpu));
2047         return 0;
2048 }
2049
2050 static int vmstat_cpu_dead(unsigned int cpu)
2051 {
2052         const struct cpumask *node_cpus;
2053         int node;
2054
2055         node = cpu_to_node(cpu);
2056
2057         refresh_zone_stat_thresholds();
2058         node_cpus = cpumask_of_node(node);
2059         if (cpumask_weight(node_cpus) > 0)
2060                 return 0;
2061
2062         node_clear_state(node, N_CPU);
2063         return 0;
2064 }
2065
2066 #endif
2067
2068 struct workqueue_struct *mm_percpu_wq;
2069
2070 void __init init_mm_internals(void)
2071 {
2072         int ret __maybe_unused;
2073
2074         mm_percpu_wq = alloc_workqueue("mm_percpu_wq", WQ_MEM_RECLAIM, 0);
2075
2076 #ifdef CONFIG_SMP
2077         ret = cpuhp_setup_state_nocalls(CPUHP_MM_VMSTAT_DEAD, "mm/vmstat:dead",
2078                                         NULL, vmstat_cpu_dead);
2079         if (ret < 0)
2080                 pr_err("vmstat: failed to register 'dead' hotplug state\n");
2081
2082         ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "mm/vmstat:online",
2083                                         vmstat_cpu_online,
2084                                         vmstat_cpu_down_prep);
2085         if (ret < 0)
2086                 pr_err("vmstat: failed to register 'online' hotplug state\n");
2087
2088         get_online_cpus();
2089         init_cpu_node_state();
2090         put_online_cpus();
2091
2092         start_shepherd_timer();
2093 #endif
2094 #ifdef CONFIG_PROC_FS
2095         proc_create_seq("buddyinfo", 0444, NULL, &fragmentation_op);
2096         proc_create_seq("pagetypeinfo", 0400, NULL, &pagetypeinfo_op);
2097         proc_create_seq("vmstat", 0444, NULL, &vmstat_op);
2098         proc_create_seq("zoneinfo", 0444, NULL, &zoneinfo_op);
2099 #endif
2100 }
2101
2102 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)
2103
2104 /*
2105  * Return an index indicating how much of the available free memory is
2106  * unusable for an allocation of the requested size.
2107  */
2108 static int unusable_free_index(unsigned int order,
2109                                 struct contig_page_info *info)
2110 {
2111         /* No free memory is interpreted as all free memory is unusable */
2112         if (info->free_pages == 0)
2113                 return 1000;
2114
2115         /*
2116          * Index should be a value between 0 and 1. Return a value to 3
2117          * decimal places.
2118          *
2119          * 0 => no fragmentation
2120          * 1 => high fragmentation
2121          */
2122         return div_u64((info->free_pages - (info->free_blocks_suitable << order)) * 1000ULL, info->free_pages);
2123
2124 }
2125
2126 static void unusable_show_print(struct seq_file *m,
2127                                         pg_data_t *pgdat, struct zone *zone)
2128 {
2129         unsigned int order;
2130         int index;
2131         struct contig_page_info info;
2132
2133         seq_printf(m, "Node %d, zone %8s ",
2134                                 pgdat->node_id,
2135                                 zone->name);
2136         for (order = 0; order < MAX_ORDER; ++order) {
2137                 fill_contig_page_info(zone, order, &info);
2138                 index = unusable_free_index(order, &info);
2139                 seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
2140         }
2141
2142         seq_putc(m, '\n');
2143 }
2144
2145 /*
2146  * Display unusable free space index
2147  *
2148  * The unusable free space index measures how much of the available free
2149  * memory cannot be used to satisfy an allocation of a given size and is a
2150  * value between 0 and 1. The higher the value, the more of free memory is
2151  * unusable and by implication, the worse the external fragmentation is. This
2152  * can be expressed as a percentage by multiplying by 100.
2153  */
2154 static int unusable_show(struct seq_file *m, void *arg)
2155 {
2156         pg_data_t *pgdat = (pg_data_t *)arg;
2157
2158         /* check memoryless node */
2159         if (!node_state(pgdat->node_id, N_MEMORY))
2160                 return 0;
2161
2162         walk_zones_in_node(m, pgdat, true, false, unusable_show_print);
2163
2164         return 0;
2165 }
2166
2167 static const struct seq_operations unusable_sops = {
2168         .start  = frag_start,
2169         .next   = frag_next,
2170         .stop   = frag_stop,
2171         .show   = unusable_show,
2172 };
2173
2174 DEFINE_SEQ_ATTRIBUTE(unusable);
2175
2176 static void extfrag_show_print(struct seq_file *m,
2177                                         pg_data_t *pgdat, struct zone *zone)
2178 {
2179         unsigned int order;
2180         int index;
2181
2182         /* Alloc on stack as interrupts are disabled for zone walk */
2183         struct contig_page_info info;
2184
2185         seq_printf(m, "Node %d, zone %8s ",
2186                                 pgdat->node_id,
2187                                 zone->name);
2188         for (order = 0; order < MAX_ORDER; ++order) {
2189                 fill_contig_page_info(zone, order, &info);
2190                 index = __fragmentation_index(order, &info);
2191                 seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
2192         }
2193
2194         seq_putc(m, '\n');
2195 }
2196
2197 /*
2198  * Display fragmentation index for orders that allocations would fail for
2199  */
2200 static int extfrag_show(struct seq_file *m, void *arg)
2201 {
2202         pg_data_t *pgdat = (pg_data_t *)arg;
2203
2204         walk_zones_in_node(m, pgdat, true, false, extfrag_show_print);
2205
2206         return 0;
2207 }
2208
2209 static const struct seq_operations extfrag_sops = {
2210         .start  = frag_start,
2211         .next   = frag_next,
2212         .stop   = frag_stop,
2213         .show   = extfrag_show,
2214 };
2215
2216 DEFINE_SEQ_ATTRIBUTE(extfrag);
2217
2218 static int __init extfrag_debug_init(void)
2219 {
2220         struct dentry *extfrag_debug_root;
2221
2222         extfrag_debug_root = debugfs_create_dir("extfrag", NULL);
2223
2224         debugfs_create_file("unusable_index", 0444, extfrag_debug_root, NULL,
2225                             &unusable_fops);
2226
2227         debugfs_create_file("extfrag_index", 0444, extfrag_debug_root, NULL,
2228                             &extfrag_fops);
2229
2230         return 0;
2231 }
2232
2233 module_init(extfrag_debug_init);
2234 #endif