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