mm/vmstat.c

   1 /*
   2  *  linux/mm/vmstat.c
   3  *
   4  *  Manages VM statistics
   5  *  Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
   6  *
   7  *  zoned VM statistics
   8  *  Copyright (C) 2006 Silicon Graphics, Inc.,
   9  *              Christoph Lameter <christoph@lameter.com>
  10  */
  11 #include <linux/fs.h>
  12 #include <linux/mm.h>
  13 #include <linux/err.h>
  14 #include <linux/module.h>
  15 #include <linux/slab.h>
  16 #include <linux/cpu.h>
  17 #include <linux/vmstat.h>
  18 #include <linux/sched.h>
  19 #include <linux/math64.h>
  20 #include <linux/writeback.h>
  21 #include <linux/compaction.h>
  22
  23 #ifdef CONFIG_VM_EVENT_COUNTERS
  24 DEFINE_PER_CPU(struct vm_event_state, vm_event_states) = {{0}};
  25 EXPORT_PER_CPU_SYMBOL(vm_event_states);
  26
  27 static void sum_vm_events(unsigned long *ret)
  28 {
  29         int cpu;
  30         int i;
  31
  32         memset(ret, 0, NR_VM_EVENT_ITEMS * sizeof(unsigned long));
  33
  34         for_each_online_cpu(cpu) {
  35                 struct vm_event_state *this = &per_cpu(vm_event_states, cpu);
  36
  37                 for (i = 0; i < NR_VM_EVENT_ITEMS; i++)
  38                         ret[i] += this->event[i];
  39         }
  40 }
  41
  42 /*
  43  * Accumulate the vm event counters across all CPUs.
  44  * The result is unavoidably approximate - it can change
  45  * during and after execution of this function.
  46 */
  47 void all_vm_events(unsigned long *ret)
  48 {
  49         get_online_cpus();
  50         sum_vm_events(ret);
  51         put_online_cpus();
  52 }
  53 EXPORT_SYMBOL_GPL(all_vm_events);
  54
  55 /*
  56  * Fold the foreign cpu events into our own.
  57  *
  58  * This is adding to the events on one processor
  59  * but keeps the global counts constant.
  60  */
  61 void vm_events_fold_cpu(int cpu)
  62 {
  63         struct vm_event_state *fold_state = &per_cpu(vm_event_states, cpu);
  64         int i;
  65
  66         for (i = 0; i < NR_VM_EVENT_ITEMS; i++) {
  67                 count_vm_events(i, fold_state->event[i]);
  68                 fold_state->event[i] = 0;
  69         }
  70 }
  71
  72 #endif /* CONFIG_VM_EVENT_COUNTERS */
  73
  74 /*
  75  * Manage combined zone based / global counters
  76  *
  77  * vm_stat contains the global counters
  78  */
  79 atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS] __cacheline_aligned_in_smp;
  80 EXPORT_SYMBOL(vm_stat);
  81
  82 #ifdef CONFIG_SMP
  83
  84 int calculate_pressure_threshold(struct zone *zone)
  85 {
  86         int threshold;
  87         int watermark_distance;
  88
  89         /*
  90          * As vmstats are not up to date, there is drift between the estimated
  91          * and real values. For high thresholds and a high number of CPUs, it
  92          * is possible for the min watermark to be breached while the estimated
  93          * value looks fine. The pressure threshold is a reduced value such
  94          * that even the maximum amount of drift will not accidentally breach
  95          * the min watermark
  96          */
  97         watermark_distance = low_wmark_pages(zone) - min_wmark_pages(zone);
  98         threshold = max(1, (int)(watermark_distance / num_online_cpus()));
  99
 100         /*
 101          * Maximum threshold is 125
 102          */
 103         threshold = min(125, threshold);
 104
 105         return threshold;
 106 }
 107
 108 int calculate_normal_threshold(struct zone *zone)
 109 {
 110         int threshold;
 111         int mem;        /* memory in 128 MB units */
 112
 113         /*
 114          * The threshold scales with the number of processors and the amount
 115          * of memory per zone. More memory means that we can defer updates for
 116          * longer, more processors could lead to more contention.
 117          * fls() is used to have a cheap way of logarithmic scaling.
 118          *
 119          * Some sample thresholds:
 120          *
 121          * Threshold    Processors      (fls)   Zonesize        fls(mem+1)
 122          * ------------------------------------------------------------------
 123          * 8            1               1       0.9-1 GB        4
 124          * 16           2               2       0.9-1 GB        4
 125          * 20           2               2       1-2 GB          5
 126          * 24           2               2       2-4 GB          6
 127          * 28           2               2       4-8 GB          7
 128          * 32           2               2       8-16 GB         8
 129          * 4            2               2       <128M           1
 130          * 30           4               3       2-4 GB          5
 131          * 48           4               3       8-16 GB         8
 132          * 32           8               4       1-2 GB          4
 133          * 32           8               4       0.9-1GB         4
 134          * 10           16              5       <128M           1
 135          * 40           16              5       900M            4
 136          * 70           64              7       2-4 GB          5
 137          * 84           64              7       4-8 GB          6
 138          * 108          512             9       4-8 GB          6
 139          * 125          1024            10      8-16 GB         8
 140          * 125          1024            10      16-32 GB        9
 141          */
 142
 143         mem = zone->managed_pages >> (27 - PAGE_SHIFT);
 144
 145         threshold = 2 * fls(num_online_cpus()) * (1 + fls(mem));
 146
 147         /*
 148          * Maximum threshold is 125
 149          */
 150         threshold = min(125, threshold);
 151
 152         return threshold;
 153 }
 154
 155 /*
 156  * Refresh the thresholds for each zone.
 157  */
 158 void refresh_zone_stat_thresholds(void)
 159 {
 160         struct zone *zone;
 161         int cpu;
 162         int threshold;
 163
 164         for_each_populated_zone(zone) {
 165                 unsigned long max_drift, tolerate_drift;
 166
 167                 threshold = calculate_normal_threshold(zone);
 168
 169                 for_each_online_cpu(cpu)
 170                         per_cpu_ptr(zone->pageset, cpu)->stat_threshold
 171                                                         = threshold;
 172
 173                 /*
 174                  * Only set percpu_drift_mark if there is a danger that
 175                  * NR_FREE_PAGES reports the low watermark is ok when in fact
 176                  * the min watermark could be breached by an allocation
 177                  */
 178                 tolerate_drift = low_wmark_pages(zone) - min_wmark_pages(zone);
 179                 max_drift = num_online_cpus() * threshold;
 180                 if (max_drift > tolerate_drift)
 181                         zone->percpu_drift_mark = high_wmark_pages(zone) +
 182                                         max_drift;
 183         }
 184 }
 185
 186 void set_pgdat_percpu_threshold(pg_data_t *pgdat,
 187                                 int (*calculate_pressure)(struct zone *))
 188 {
 189         struct zone *zone;
 190         int cpu;
 191         int threshold;
 192         int i;
 193
 194         for (i = 0; i < pgdat->nr_zones; i++) {
 195                 zone = &pgdat->node_zones[i];
 196                 if (!zone->percpu_drift_mark)
 197                         continue;
 198
 199                 threshold = (*calculate_pressure)(zone);
 200                 for_each_possible_cpu(cpu)
 201                         per_cpu_ptr(zone->pageset, cpu)->stat_threshold
 202                                                         = threshold;
 203         }
 204 }
 205
 206 /*
 207  * For use when we know that interrupts are disabled.
 208  */
 209 void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 210                                 int delta)
 211 {
 212         struct per_cpu_pageset __percpu *pcp = zone->pageset;
 213         s8 __percpu *p = pcp->vm_stat_diff + item;
 214         long x;
 215         long t;
 216
 217         x = delta + __this_cpu_read(*p);
 218
 219         t = __this_cpu_read(pcp->stat_threshold);
 220
 221         if (unlikely(x > t || x < -t)) {
 222                 zone_page_state_add(x, zone, item);
 223                 x = 0;
 224         }
 225         __this_cpu_write(*p, x);
 226 }
 227 EXPORT_SYMBOL(__mod_zone_page_state);
 228
 229 /*
 230  * Optimized increment and decrement functions.
 231  *
 232  * These are only for a single page and therefore can take a struct page *
 233  * argument instead of struct zone *. This allows the inclusion of the code
 234  * generated for page_zone(page) into the optimized functions.
 235  *
 236  * No overflow check is necessary and therefore the differential can be
 237  * incremented or decremented in place which may allow the compilers to
 238  * generate better code.
 239  * The increment or decrement is known and therefore one boundary check can
 240  * be omitted.
 241  *
 242  * NOTE: These functions are very performance sensitive. Change only
 243  * with care.
 244  *
 245  * Some processors have inc/dec instructions that are atomic vs an interrupt.
 246  * However, the code must first determine the differential location in a zone
 247  * based on the processor number and then inc/dec the counter. There is no
 248  * guarantee without disabling preemption that the processor will not change
 249  * in between and therefore the atomicity vs. interrupt cannot be exploited
 250  * in a useful way here.
 251  */
 252 void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
 253 {
 254         struct per_cpu_pageset __percpu *pcp = zone->pageset;
 255         s8 __percpu *p = pcp->vm_stat_diff + item;
 256         s8 v, t;
 257
 258         v = __this_cpu_inc_return(*p);
 259         t = __this_cpu_read(pcp->stat_threshold);
 260         if (unlikely(v > t)) {
 261                 s8 overstep = t >> 1;
 262
 263                 zone_page_state_add(v + overstep, zone, item);
 264                 __this_cpu_write(*p, -overstep);
 265         }
 266 }
 267
 268 void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
 269 {
 270         __inc_zone_state(page_zone(page), item);
 271 }
 272 EXPORT_SYMBOL(__inc_zone_page_state);
 273
 274 void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
 275 {
 276         struct per_cpu_pageset __percpu *pcp = zone->pageset;
 277         s8 __percpu *p = pcp->vm_stat_diff + item;
 278         s8 v, t;
 279
 280         v = __this_cpu_dec_return(*p);
 281         t = __this_cpu_read(pcp->stat_threshold);
 282         if (unlikely(v < - t)) {
 283                 s8 overstep = t >> 1;
 284
 285                 zone_page_state_add(v - overstep, zone, item);
 286                 __this_cpu_write(*p, overstep);
 287         }
 288 }
 289
 290 void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
 291 {
 292         __dec_zone_state(page_zone(page), item);
 293 }
 294 EXPORT_SYMBOL(__dec_zone_page_state);
 295
 296 #ifdef CONFIG_HAVE_CMPXCHG_LOCAL
 297 /*
 298  * If we have cmpxchg_local support then we do not need to incur the overhead
 299  * that comes with local_irq_save/restore if we use this_cpu_cmpxchg.
 300  *
 301  * mod_state() modifies the zone counter state through atomic per cpu
 302  * operations.
 303  *
 304  * Overstep mode specifies how overstep should handled:
 305  *     0       No overstepping
 306  *     1       Overstepping half of threshold
 307  *     -1      Overstepping minus half of threshold
 308 */
 309 static inline void mod_state(struct zone *zone,
 310        enum zone_stat_item item, int delta, int overstep_mode)
 311 {
 312         struct per_cpu_pageset __percpu *pcp = zone->pageset;
 313         s8 __percpu *p = pcp->vm_stat_diff + item;
 314         long o, n, t, z;
 315
 316         do {
 317                 z = 0;  /* overflow to zone counters */
 318
 319                 /*
 320                  * The fetching of the stat_threshold is racy. We may apply
 321                  * a counter threshold to the wrong the cpu if we get
 322                  * rescheduled while executing here. However, the next
 323                  * counter update will apply the threshold again and
 324                  * therefore bring the counter under the threshold again.
 325                  *
 326                  * Most of the time the thresholds are the same anyways
 327                  * for all cpus in a zone.
 328                  */
 329                 t = this_cpu_read(pcp->stat_threshold);
 330
 331                 o = this_cpu_read(*p);
 332                 n = delta + o;
 333
 334                 if (n > t || n < -t) {
 335                         int os = overstep_mode * (t >> 1) ;
 336
 337                         /* Overflow must be added to zone counters */
 338                         z = n + os;
 339                         n = -os;
 340                 }
 341         } while (this_cpu_cmpxchg(*p, o, n) != o);
 342
 343         if (z)
 344                 zone_page_state_add(z, zone, item);
 345 }
 346
 347 void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 348                                         int delta)
 349 {
 350         mod_state(zone, item, delta, 0);
 351 }
 352 EXPORT_SYMBOL(mod_zone_page_state);
 353
 354 void inc_zone_state(struct zone *zone, enum zone_stat_item item)
 355 {
 356         mod_state(zone, item, 1, 1);
 357 }
 358
 359 void inc_zone_page_state(struct page *page, enum zone_stat_item item)
 360 {
 361         mod_state(page_zone(page), item, 1, 1);
 362 }
 363 EXPORT_SYMBOL(inc_zone_page_state);
 364
 365 void dec_zone_page_state(struct page *page, enum zone_stat_item item)
 366 {
 367         mod_state(page_zone(page), item, -1, -1);
 368 }
 369 EXPORT_SYMBOL(dec_zone_page_state);
 370 #else
 371 /*
 372  * Use interrupt disable to serialize counter updates
 373  */
 374 void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 375                                         int delta)
 376 {
 377         unsigned long flags;
 378
 379         local_irq_save(flags);
 380         __mod_zone_page_state(zone, item, delta);
 381         local_irq_restore(flags);
 382 }
 383 EXPORT_SYMBOL(mod_zone_page_state);
 384
 385 void inc_zone_state(struct zone *zone, enum zone_stat_item item)
 386 {
 387         unsigned long flags;
 388
 389         local_irq_save(flags);
 390         __inc_zone_state(zone, item);
 391         local_irq_restore(flags);
 392 }
 393
 394 void inc_zone_page_state(struct page *page, enum zone_stat_item item)
 395 {
 396         unsigned long flags;
 397         struct zone *zone;
 398
 399         zone = page_zone(page);
 400         local_irq_save(flags);
 401         __inc_zone_state(zone, item);
 402         local_irq_restore(flags);
 403 }
 404 EXPORT_SYMBOL(inc_zone_page_state);
 405
 406 void dec_zone_page_state(struct page *page, enum zone_stat_item item)
 407 {
 408         unsigned long flags;
 409
 410         local_irq_save(flags);
 411         __dec_zone_page_state(page, item);
 412         local_irq_restore(flags);
 413 }
 414 EXPORT_SYMBOL(dec_zone_page_state);
 415 #endif
 416
 417 /*
 418  * Update the zone counters for the current cpu.
 419  *
 420  * Note that refresh_cpu_vm_stats strives to only access
 421  * node local memory. The per cpu pagesets on remote zones are placed
 422  * in the memory local to the processor using that pageset. So the
 423  * loop over all zones will access a series of cachelines local to
 424  * the processor.
 425  *
 426  * The call to zone_page_state_add updates the cachelines with the
 427  * statistics in the remote zone struct as well as the global cachelines
 428  * with the global counters. These could cause remote node cache line
 429  * bouncing and will have to be only done when necessary.
 430  */
 431 static void refresh_cpu_vm_stats(int cpu)
 432 {
 433         struct zone *zone;
 434         int i;
 435         int global_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
 436
 437         for_each_populated_zone(zone) {
 438                 struct per_cpu_pageset *p;
 439
 440                 p = per_cpu_ptr(zone->pageset, cpu);
 441
 442                 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 443                         if (p->vm_stat_diff[i]) {
 444                                 unsigned long flags;
 445                                 int v;
 446
 447                                 local_irq_save(flags);
 448                                 v = p->vm_stat_diff[i];
 449                                 p->vm_stat_diff[i] = 0;
 450                                 local_irq_restore(flags);
 451                                 atomic_long_add(v, &zone->vm_stat[i]);
 452                                 global_diff[i] += v;
 453 #ifdef CONFIG_NUMA
 454                                 /* 3 seconds idle till flush */
 455                                 p->expire = 3;
 456 #endif
 457                         }
 458                 cond_resched();
 459 #ifdef CONFIG_NUMA
 460                 /*
 461                  * Deal with draining the remote pageset of this
 462                  * processor
 463                  *
 464                  * Check if there are pages remaining in this pageset
 465                  * if not then there is nothing to expire.
 466                  */
 467                 if (!p->expire || !p->pcp.count)
 468                         continue;
 469
 470                 /*
 471                  * We never drain zones local to this processor.
 472                  */
 473                 if (zone_to_nid(zone) == numa_node_id()) {
 474                         p->expire = 0;
 475                         continue;
 476                 }
 477
 478                 p->expire--;
 479                 if (p->expire)
 480                         continue;
 481
 482                 if (p->pcp.count)
 483                         drain_zone_pages(zone, &p->pcp);
 484 #endif
 485         }
 486
 487         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 488                 if (global_diff[i])
 489                         atomic_long_add(global_diff[i], &vm_stat[i]);
 490 }
 491
 492 /*
 493  * Fold the data for an offline cpu into the global array.
 494  * There cannot be any access by the offline cpu and therefore
 495  * synchronization is simplified.
 496  */
 497 void cpu_vm_stats_fold(int cpu)
 498 {
 499         struct zone *zone;
 500         int i;
 501         int global_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
 502
 503         for_each_populated_zone(zone) {
 504                 struct per_cpu_pageset *p;
 505
 506                 p = per_cpu_ptr(zone->pageset, cpu);
 507
 508                 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 509                         if (p->vm_stat_diff[i]) {
 510                                 int v;
 511
 512                                 v = p->vm_stat_diff[i];
 513                                 p->vm_stat_diff[i] = 0;
 514                                 atomic_long_add(v, &zone->vm_stat[i]);
 515                                 global_diff[i] += v;
 516                         }
 517         }
 518
 519         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 520                 if (global_diff[i])
 521                         atomic_long_add(global_diff[i], &vm_stat[i]);
 522 }
 523
 524 /*
 525  * this is only called if !populated_zone(zone), which implies no other users of
 526  * pset->vm_stat_diff[] exsist.
 527  */
 528 void drain_zonestat(struct zone *zone, struct per_cpu_pageset *pset)
 529 {
 530         int i;
 531
 532         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 533                 if (pset->vm_stat_diff[i]) {
 534                         int v = pset->vm_stat_diff[i];
 535                         pset->vm_stat_diff[i] = 0;
 536                         atomic_long_add(v, &zone->vm_stat[i]);
 537                         atomic_long_add(v, &vm_stat[i]);
 538                 }
 539 }
 540 #endif
 541
 542 #ifdef CONFIG_NUMA
 543 /*
 544  * zonelist = the list of zones passed to the allocator
 545  * z        = the zone from which the allocation occurred.
 546  *
 547  * Must be called with interrupts disabled.
 548  *
 549  * When __GFP_OTHER_NODE is set assume the node of the preferred
 550  * zone is the local node. This is useful for daemons who allocate
 551  * memory on behalf of other processes.
 552  */
 553 void zone_statistics(struct zone *preferred_zone, struct zone *z, gfp_t flags)
 554 {
 555         if (z->zone_pgdat == preferred_zone->zone_pgdat) {
 556                 __inc_zone_state(z, NUMA_HIT);
 557         } else {
 558                 __inc_zone_state(z, NUMA_MISS);
 559                 __inc_zone_state(preferred_zone, NUMA_FOREIGN);
 560         }
 561         if (z->node == ((flags & __GFP_OTHER_NODE) ?
 562                         preferred_zone->node : numa_node_id()))
 563                 __inc_zone_state(z, NUMA_LOCAL);
 564         else
 565                 __inc_zone_state(z, NUMA_OTHER);
 566 }
 567 #endif
 568
 569 #ifdef CONFIG_COMPACTION
 570
 571 struct contig_page_info {
 572         unsigned long free_pages;
 573         unsigned long free_blocks_total;
 574         unsigned long free_blocks_suitable;
 575 };
 576
 577 /*
 578  * Calculate the number of free pages in a zone, how many contiguous
 579  * pages are free and how many are large enough to satisfy an allocation of
 580  * the target size. Note that this function makes no attempt to estimate
 581  * how many suitable free blocks there *might* be if MOVABLE pages were
 582  * migrated. Calculating that is possible, but expensive and can be
 583  * figured out from userspace
 584  */
 585 static void fill_contig_page_info(struct zone *zone,
 586                                 unsigned int suitable_order,
 587                                 struct contig_page_info *info)
 588 {
 589         unsigned int order;
 590
 591         info->free_pages = 0;
 592         info->free_blocks_total = 0;
 593         info->free_blocks_suitable = 0;
 594
 595         for (order = 0; order < MAX_ORDER; order++) {
 596                 unsigned long blocks;
 597
 598                 /* Count number of free blocks */
 599                 blocks = zone->free_area[order].nr_free;
 600                 info->free_blocks_total += blocks;
 601
 602                 /* Count free base pages */
 603                 info->free_pages += blocks << order;
 604
 605                 /* Count the suitable free blocks */
 606                 if (order >= suitable_order)
 607                         info->free_blocks_suitable += blocks <<
 608                                                 (order - suitable_order);
 609         }
 610 }
 611
 612 /*
 613  * A fragmentation index only makes sense if an allocation of a requested
 614  * size would fail. If that is true, the fragmentation index indicates
 615  * whether external fragmentation or a lack of memory was the problem.
 616  * The value can be used to determine if page reclaim or compaction
 617  * should be used
 618  */
 619 static int __fragmentation_index(unsigned int order, struct contig_page_info *info)
 620 {
 621         unsigned long requested = 1UL << order;
 622
 623         if (!info->free_blocks_total)
 624                 return 0;
 625
 626         /* Fragmentation index only makes sense when a request would fail */
 627         if (info->free_blocks_suitable)
 628                 return -1000;
 629
 630         /*
 631          * Index is between 0 and 1 so return within 3 decimal places
 632          *
 633          * 0 => allocation would fail due to lack of memory
 634          * 1 => allocation would fail due to fragmentation
 635          */
 636         return 1000 - div_u64( (1000+(div_u64(info->free_pages * 1000ULL, requested))), info->free_blocks_total);
 637 }
 638
 639 /* Same as __fragmentation index but allocs contig_page_info on stack */
 640 int fragmentation_index(struct zone *zone, unsigned int order)
 641 {
 642         struct contig_page_info info;
 643
 644         fill_contig_page_info(zone, order, &info);
 645         return __fragmentation_index(order, &info);
 646 }
 647 #endif
 648
 649 #if defined(CONFIG_PROC_FS) || defined(CONFIG_COMPACTION)
 650 #include <linux/proc_fs.h>
 651 #include <linux/seq_file.h>
 652
 653 static char * const migratetype_names[MIGRATE_TYPES] = {
 654         "Unmovable",
 655         "Reclaimable",
 656         "Movable",
 657         "Reserve",
 658 #ifdef CONFIG_CMA
 659         "CMA",
 660 #endif
 661 #ifdef CONFIG_MEMORY_ISOLATION
 662         "Isolate",
 663 #endif
 664 };
 665
 666 static void *frag_start(struct seq_file *m, loff_t *pos)
 667 {
 668         pg_data_t *pgdat;
 669         loff_t node = *pos;
 670         for (pgdat = first_online_pgdat();
 671              pgdat && node;
 672              pgdat = next_online_pgdat(pgdat))
 673                 --node;
 674
 675         return pgdat;
 676 }
 677
 678 static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
 679 {
 680         pg_data_t *pgdat = (pg_data_t *)arg;
 681
 682         (*pos)++;
 683         return next_online_pgdat(pgdat);
 684 }
 685
 686 static void frag_stop(struct seq_file *m, void *arg)
 687 {
 688 }
 689
 690 /* Walk all the zones in a node and print using a callback */
 691 static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat,
 692                 void (*print)(struct seq_file *m, pg_data_t *, struct zone *))
 693 {
 694         struct zone *zone;
 695         struct zone *node_zones = pgdat->node_zones;
 696         unsigned long flags;
 697
 698         for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
 699                 if (!populated_zone(zone))
 700                         continue;
 701
 702                 spin_lock_irqsave(&zone->lock, flags);
 703                 print(m, pgdat, zone);
 704                 spin_unlock_irqrestore(&zone->lock, flags);
 705         }
 706 }
 707 #endif
 708
 709 #if defined(CONFIG_PROC_FS) || defined(CONFIG_SYSFS) || defined(CONFIG_NUMA)
 710 #ifdef CONFIG_ZONE_DMA
 711 #define TEXT_FOR_DMA(xx) xx "_dma",
 712 #else
 713 #define TEXT_FOR_DMA(xx)
 714 #endif
 715
 716 #ifdef CONFIG_ZONE_DMA32
 717 #define TEXT_FOR_DMA32(xx) xx "_dma32",
 718 #else
 719 #define TEXT_FOR_DMA32(xx)
 720 #endif
 721
 722 #ifdef CONFIG_HIGHMEM
 723 #define TEXT_FOR_HIGHMEM(xx) xx "_high",
 724 #else
 725 #define TEXT_FOR_HIGHMEM(xx)
 726 #endif
 727
 728 #define TEXTS_FOR_ZONES(xx) TEXT_FOR_DMA(xx) TEXT_FOR_DMA32(xx) xx "_normal", \
 729                                         TEXT_FOR_HIGHMEM(xx) xx "_movable",
 730
 731 const char * const vmstat_text[] = {
 732         /* Zoned VM counters */
 733         "nr_free_pages",
 734         "nr_alloc_batch",
 735         "nr_inactive_anon",
 736         "nr_active_anon",
 737         "nr_inactive_file",
 738         "nr_active_file",
 739         "nr_unevictable",
 740         "nr_mlock",
 741         "nr_anon_pages",
 742         "nr_mapped",
 743         "nr_file_pages",
 744         "nr_dirty",
 745         "nr_writeback",
 746         "nr_slab_reclaimable",
 747         "nr_slab_unreclaimable",
 748         "nr_page_table_pages",
 749         "nr_kernel_stack",
 750         "nr_unstable",
 751         "nr_bounce",
 752         "nr_vmscan_write",
 753         "nr_vmscan_immediate_reclaim",
 754         "nr_writeback_temp",
 755         "nr_isolated_anon",
 756         "nr_isolated_file",
 757         "nr_shmem",
 758         "nr_dirtied",
 759         "nr_written",
 760
 761 #ifdef CONFIG_NUMA
 762         "numa_hit",
 763         "numa_miss",
 764         "numa_foreign",
 765         "numa_interleave",
 766         "numa_local",
 767         "numa_other",
 768 #endif
 769         "nr_anon_transparent_hugepages",
 770         "nr_free_cma",
 771         "nr_dirty_threshold",
 772         "nr_dirty_background_threshold",
 773
 774 #ifdef CONFIG_VM_EVENT_COUNTERS
 775         "pgpgin",
 776         "pgpgout",
 777         "pswpin",
 778         "pswpout",
 779
 780         TEXTS_FOR_ZONES("pgalloc")
 781
 782         "pgfree",
 783         "pgactivate",
 784         "pgdeactivate",
 785
 786         "pgfault",
 787         "pgmajfault",
 788
 789         TEXTS_FOR_ZONES("pgrefill")
 790         TEXTS_FOR_ZONES("pgsteal_kswapd")
 791         TEXTS_FOR_ZONES("pgsteal_direct")
 792         TEXTS_FOR_ZONES("pgscan_kswapd")
 793         TEXTS_FOR_ZONES("pgscan_direct")
 794         "pgscan_direct_throttle",
 795
 796 #ifdef CONFIG_NUMA
 797         "zone_reclaim_failed",
 798 #endif
 799         "pginodesteal",
 800         "slabs_scanned",
 801         "kswapd_inodesteal",
 802         "kswapd_low_wmark_hit_quickly",
 803         "kswapd_high_wmark_hit_quickly",
 804         "pageoutrun",
 805         "allocstall",
 806
 807         "pgrotated",
 808
 809 #ifdef CONFIG_NUMA_BALANCING
 810         "numa_pte_updates",
 811         "numa_hint_faults",
 812         "numa_hint_faults_local",
 813         "numa_pages_migrated",
 814 #endif
 815 #ifdef CONFIG_MIGRATION
 816         "pgmigrate_success",
 817         "pgmigrate_fail",
 818 #endif
 819 #ifdef CONFIG_COMPACTION
 820         "compact_migrate_scanned",
 821         "compact_free_scanned",
 822         "compact_isolated",
 823         "compact_stall",
 824         "compact_fail",
 825         "compact_success",
 826 #endif
 827
 828 #ifdef CONFIG_HUGETLB_PAGE
 829         "htlb_buddy_alloc_success",
 830         "htlb_buddy_alloc_fail",
 831 #endif
 832         "unevictable_pgs_culled",
 833         "unevictable_pgs_scanned",
 834         "unevictable_pgs_rescued",
 835         "unevictable_pgs_mlocked",
 836         "unevictable_pgs_munlocked",
 837         "unevictable_pgs_cleared",
 838         "unevictable_pgs_stranded",
 839
 840 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 841         "thp_fault_alloc",
 842         "thp_fault_fallback",
 843         "thp_collapse_alloc",
 844         "thp_collapse_alloc_failed",
 845         "thp_split",
 846         "thp_zero_page_alloc",
 847         "thp_zero_page_alloc_failed",
 848 #endif
 849 #ifdef CONFIG_SMP
 850         "nr_tlb_remote_flush",
 851         "nr_tlb_remote_flush_received",
 852 #endif
 853         "nr_tlb_local_flush_all",
 854         "nr_tlb_local_flush_one",
 855
 856 #endif /* CONFIG_VM_EVENTS_COUNTERS */
 857 };
 858 #endif /* CONFIG_PROC_FS || CONFIG_SYSFS || CONFIG_NUMA */
 859
 860
 861 #ifdef CONFIG_PROC_FS
 862 static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,
 863                                                 struct zone *zone)
 864 {
 865         int order;
 866
 867         seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
 868         for (order = 0; order < MAX_ORDER; ++order)
 869                 seq_printf(m, "%6lu ", zone->free_area[order].nr_free);
 870         seq_putc(m, '\n');
 871 }
 872
 873 /*
 874  * This walks the free areas for each zone.
 875  */
 876 static int frag_show(struct seq_file *m, void *arg)
 877 {
 878         pg_data_t *pgdat = (pg_data_t *)arg;
 879         walk_zones_in_node(m, pgdat, frag_show_print);
 880         return 0;
 881 }
 882
 883 static void pagetypeinfo_showfree_print(struct seq_file *m,
 884                                         pg_data_t *pgdat, struct zone *zone)
 885 {
 886         int order, mtype;
 887
 888         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++) {
 889                 seq_printf(m, "Node %4d, zone %8s, type %12s ",
 890                                         pgdat->node_id,
 891                                         zone->name,
 892                                         migratetype_names[mtype]);
 893                 for (order = 0; order < MAX_ORDER; ++order) {
 894                         unsigned long freecount = 0;
 895                         struct free_area *area;
 896                         struct list_head *curr;
 897
 898                         area = &(zone->free_area[order]);
 899
 900                         list_for_each(curr, &area->free_list[mtype])
 901                                 freecount++;
 902                         seq_printf(m, "%6lu ", freecount);
 903                 }
 904                 seq_putc(m, '\n');
 905         }
 906 }
 907
 908 /* Print out the free pages at each order for each migatetype */
 909 static int pagetypeinfo_showfree(struct seq_file *m, void *arg)
 910 {
 911         int order;
 912         pg_data_t *pgdat = (pg_data_t *)arg;
 913
 914         /* Print header */
 915         seq_printf(m, "%-43s ", "Free pages count per migrate type at order");
 916         for (order = 0; order < MAX_ORDER; ++order)
 917                 seq_printf(m, "%6d ", order);
 918         seq_putc(m, '\n');
 919
 920         walk_zones_in_node(m, pgdat, pagetypeinfo_showfree_print);
 921
 922         return 0;
 923 }
 924
 925 static void pagetypeinfo_showblockcount_print(struct seq_file *m,
 926                                         pg_data_t *pgdat, struct zone *zone)
 927 {
 928         int mtype;
 929         unsigned long pfn;
 930         unsigned long start_pfn = zone->zone_start_pfn;
 931         unsigned long end_pfn = zone_end_pfn(zone);
 932         unsigned long count[MIGRATE_TYPES] = { 0, };
 933
 934         for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
 935                 struct page *page;
 936
 937                 if (!pfn_valid(pfn))
 938                         continue;
 939
 940                 page = pfn_to_page(pfn);
 941
 942                 /* Watch for unexpected holes punched in the memmap */
 943                 if (!memmap_valid_within(pfn, page, zone))
 944                         continue;
 945
 946                 mtype = get_pageblock_migratetype(page);
 947
 948                 if (mtype < MIGRATE_TYPES)
 949                         count[mtype]++;
 950         }
 951
 952         /* Print counts */
 953         seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
 954         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
 955                 seq_printf(m, "%12lu ", count[mtype]);
 956         seq_putc(m, '\n');
 957 }
 958
 959 /* Print out the free pages at each order for each migratetype */
 960 static int pagetypeinfo_showblockcount(struct seq_file *m, void *arg)
 961 {
 962         int mtype;
 963         pg_data_t *pgdat = (pg_data_t *)arg;
 964
 965         seq_printf(m, "\n%-23s", "Number of blocks type ");
 966         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
 967                 seq_printf(m, "%12s ", migratetype_names[mtype]);
 968         seq_putc(m, '\n');
 969         walk_zones_in_node(m, pgdat, pagetypeinfo_showblockcount_print);
 970
 971         return 0;
 972 }
 973
 974 /*
 975  * This prints out statistics in relation to grouping pages by mobility.
 976  * It is expensive to collect so do not constantly read the file.
 977  */
 978 static int pagetypeinfo_show(struct seq_file *m, void *arg)
 979 {
 980         pg_data_t *pgdat = (pg_data_t *)arg;
 981
 982         /* check memoryless node */
 983         if (!node_state(pgdat->node_id, N_MEMORY))
 984                 return 0;
 985
 986         seq_printf(m, "Page block order: %d\n", pageblock_order);
 987         seq_printf(m, "Pages per block:  %lu\n", pageblock_nr_pages);
 988         seq_putc(m, '\n');
 989         pagetypeinfo_showfree(m, pgdat);
 990         pagetypeinfo_showblockcount(m, pgdat);
 991
 992         return 0;
 993 }
 994
 995 static const struct seq_operations fragmentation_op = {
 996         .start  = frag_start,
 997         .next   = frag_next,
 998         .stop   = frag_stop,
 999         .show   = frag_show,
1000 };
1001
1002 static int fragmentation_open(struct inode *inode, struct file *file)
1003 {
1004         return seq_open(file, &fragmentation_op);
1005 }
1006
1007 static const struct file_operations fragmentation_file_operations = {
1008         .open           = fragmentation_open,
1009         .read           = seq_read,
1010         .llseek         = seq_lseek,
1011         .release        = seq_release,
1012 };
1013
1014 static const struct seq_operations pagetypeinfo_op = {
1015         .start  = frag_start,
1016         .next   = frag_next,
1017         .stop   = frag_stop,
1018         .show   = pagetypeinfo_show,
1019 };
1020
1021 static int pagetypeinfo_open(struct inode *inode, struct file *file)
1022 {
1023         return seq_open(file, &pagetypeinfo_op);
1024 }
1025
1026 static const struct file_operations pagetypeinfo_file_ops = {
1027         .open           = pagetypeinfo_open,
1028         .read           = seq_read,
1029         .llseek         = seq_lseek,
1030         .release        = seq_release,
1031 };
1032
1033 static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
1034                                                         struct zone *zone)
1035 {
1036         int i;
1037         seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name);
1038         seq_printf(m,
1039                    "\n  pages free     %lu"
1040                    "\n        min      %lu"
1041                    "\n        low      %lu"
1042                    "\n        high     %lu"
1043                    "\n        scanned  %lu"
1044                    "\n        spanned  %lu"
1045                    "\n        present  %lu"
1046                    "\n        managed  %lu",
1047                    zone_page_state(zone, NR_FREE_PAGES),
1048                    min_wmark_pages(zone),
1049                    low_wmark_pages(zone),
1050                    high_wmark_pages(zone),
1051                    zone->pages_scanned,
1052                    zone->spanned_pages,
1053                    zone->present_pages,
1054                    zone->managed_pages);
1055
1056         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
1057                 seq_printf(m, "\n    %-12s %lu", vmstat_text[i],
1058                                 zone_page_state(zone, i));
1059
1060         seq_printf(m,
1061                    "\n        protection: (%lu",
1062                    zone->lowmem_reserve[0]);
1063         for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++)
1064                 seq_printf(m, ", %lu", zone->lowmem_reserve[i]);
1065         seq_printf(m,
1066                    ")"
1067                    "\n  pagesets");
1068         for_each_online_cpu(i) {
1069                 struct per_cpu_pageset *pageset;
1070
1071                 pageset = per_cpu_ptr(zone->pageset, i);
1072                 seq_printf(m,
1073                            "\n    cpu: %i"
1074                            "\n              count: %i"
1075                            "\n              high:  %i"
1076                            "\n              batch: %i",
1077                            i,
1078                            pageset->pcp.count,
1079                            pageset->pcp.high,
1080                            pageset->pcp.batch);
1081 #ifdef CONFIG_SMP
1082                 seq_printf(m, "\n  vm stats threshold: %d",
1083                                 pageset->stat_threshold);
1084 #endif
1085         }
1086         seq_printf(m,
1087                    "\n  all_unreclaimable: %u"
1088                    "\n  start_pfn:         %lu"
1089                    "\n  inactive_ratio:    %u",
1090                    zone->all_unreclaimable,
1091                    zone->zone_start_pfn,
1092                    zone->inactive_ratio);
1093         seq_putc(m, '\n');
1094 }
1095
1096 /*
1097  * Output information about zones in @pgdat.
1098  */
1099 static int zoneinfo_show(struct seq_file *m, void *arg)
1100 {
1101         pg_data_t *pgdat = (pg_data_t *)arg;
1102         walk_zones_in_node(m, pgdat, zoneinfo_show_print);
1103         return 0;
1104 }
1105
1106 static const struct seq_operations zoneinfo_op = {
1107         .start  = frag_start, /* iterate over all zones. The same as in
1108                                * fragmentation. */
1109         .next   = frag_next,
1110         .stop   = frag_stop,
1111         .show   = zoneinfo_show,
1112 };
1113
1114 static int zoneinfo_open(struct inode *inode, struct file *file)
1115 {
1116         return seq_open(file, &zoneinfo_op);
1117 }
1118
1119 static const struct file_operations proc_zoneinfo_file_operations = {
1120         .open           = zoneinfo_open,
1121         .read           = seq_read,
1122         .llseek         = seq_lseek,
1123         .release        = seq_release,
1124 };
1125
1126 enum writeback_stat_item {
1127         NR_DIRTY_THRESHOLD,
1128         NR_DIRTY_BG_THRESHOLD,
1129         NR_VM_WRITEBACK_STAT_ITEMS,
1130 };
1131
1132 static void *vmstat_start(struct seq_file *m, loff_t *pos)
1133 {
1134         unsigned long *v;
1135         int i, stat_items_size;
1136
1137         if (*pos >= ARRAY_SIZE(vmstat_text))
1138                 return NULL;
1139         stat_items_size = NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long) +
1140                           NR_VM_WRITEBACK_STAT_ITEMS * sizeof(unsigned long);
1141
1142 #ifdef CONFIG_VM_EVENT_COUNTERS
1143         stat_items_size += sizeof(struct vm_event_state);
1144 #endif
1145
1146         v = kmalloc(stat_items_size, GFP_KERNEL);
1147         m->private = v;
1148         if (!v)
1149                 return ERR_PTR(-ENOMEM);
1150         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
1151                 v[i] = global_page_state(i);
1152         v += NR_VM_ZONE_STAT_ITEMS;
1153
1154         global_dirty_limits(v + NR_DIRTY_BG_THRESHOLD,
1155                             v + NR_DIRTY_THRESHOLD);
1156         v += NR_VM_WRITEBACK_STAT_ITEMS;
1157
1158 #ifdef CONFIG_VM_EVENT_COUNTERS
1159         all_vm_events(v);
1160         v[PGPGIN] /= 2;         /* sectors -> kbytes */
1161         v[PGPGOUT] /= 2;
1162 #endif
1163         return (unsigned long *)m->private + *pos;
1164 }
1165
1166 static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)
1167 {
1168         (*pos)++;
1169         if (*pos >= ARRAY_SIZE(vmstat_text))
1170                 return NULL;
1171         return (unsigned long *)m->private + *pos;
1172 }
1173
1174 static int vmstat_show(struct seq_file *m, void *arg)
1175 {
1176         unsigned long *l = arg;
1177         unsigned long off = l - (unsigned long *)m->private;
1178
1179         seq_printf(m, "%s %lu\n", vmstat_text[off], *l);
1180         return 0;
1181 }
1182
1183 static void vmstat_stop(struct seq_file *m, void *arg)
1184 {
1185         kfree(m->private);
1186         m->private = NULL;
1187 }
1188
1189 static const struct seq_operations vmstat_op = {
1190         .start  = vmstat_start,
1191         .next   = vmstat_next,
1192         .stop   = vmstat_stop,
1193         .show   = vmstat_show,
1194 };
1195
1196 static int vmstat_open(struct inode *inode, struct file *file)
1197 {
1198         return seq_open(file, &vmstat_op);
1199 }
1200
1201 static const struct file_operations proc_vmstat_file_operations = {
1202         .open           = vmstat_open,
1203         .read           = seq_read,
1204         .llseek         = seq_lseek,
1205         .release        = seq_release,
1206 };
1207 #endif /* CONFIG_PROC_FS */
1208
1209 #ifdef CONFIG_SMP
1210 static DEFINE_PER_CPU(struct delayed_work, vmstat_work);
1211 int sysctl_stat_interval __read_mostly = HZ;
1212
1213 static void vmstat_update(struct work_struct *w)
1214 {
1215         refresh_cpu_vm_stats(smp_processor_id());
1216         schedule_delayed_work(&__get_cpu_var(vmstat_work),
1217                 round_jiffies_relative(sysctl_stat_interval));
1218 }
1219
1220 static void start_cpu_timer(int cpu)
1221 {
1222         struct delayed_work *work = &per_cpu(vmstat_work, cpu);
1223
1224         INIT_DEFERRABLE_WORK(work, vmstat_update);
1225         schedule_delayed_work_on(cpu, work, __round_jiffies_relative(HZ, cpu));
1226 }
1227
1228 /*
1229  * Use the cpu notifier to insure that the thresholds are recalculated
1230  * when necessary.
1231  */
1232 static int vmstat_cpuup_callback(struct notifier_block *nfb,
1233                 unsigned long action,
1234                 void *hcpu)
1235 {
1236         long cpu = (long)hcpu;
1237
1238         switch (action) {
1239         case CPU_ONLINE:
1240         case CPU_ONLINE_FROZEN:
1241                 refresh_zone_stat_thresholds();
1242                 start_cpu_timer(cpu);
1243                 node_set_state(cpu_to_node(cpu), N_CPU);
1244                 break;
1245         case CPU_DOWN_PREPARE:
1246         case CPU_DOWN_PREPARE_FROZEN:
1247                 cancel_delayed_work_sync(&per_cpu(vmstat_work, cpu));
1248                 per_cpu(vmstat_work, cpu).work.func = NULL;
1249                 break;
1250         case CPU_DOWN_FAILED:
1251         case CPU_DOWN_FAILED_FROZEN:
1252                 start_cpu_timer(cpu);
1253                 break;
1254         case CPU_DEAD:
1255         case CPU_DEAD_FROZEN:
1256                 refresh_zone_stat_thresholds();
1257                 break;
1258         default:
1259                 break;
1260         }
1261         return NOTIFY_OK;
1262 }
1263
1264 static struct notifier_block vmstat_notifier =
1265         { &vmstat_cpuup_callback, NULL, 0 };
1266 #endif
1267
1268 static int __init setup_vmstat(void)
1269 {
1270 #ifdef CONFIG_SMP
1271         int cpu;
1272
1273         register_cpu_notifier(&vmstat_notifier);
1274
1275         for_each_online_cpu(cpu)
1276                 start_cpu_timer(cpu);
1277 #endif
1278 #ifdef CONFIG_PROC_FS
1279         proc_create("buddyinfo", S_IRUGO, NULL, &fragmentation_file_operations);
1280         proc_create("pagetypeinfo", S_IRUGO, NULL, &pagetypeinfo_file_ops);
1281         proc_create("vmstat", S_IRUGO, NULL, &proc_vmstat_file_operations);
1282         proc_create("zoneinfo", S_IRUGO, NULL, &proc_zoneinfo_file_operations);
1283 #endif
1284         return 0;
1285 }
1286 module_init(setup_vmstat)
1287
1288 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)
1289 #include <linux/debugfs.h>
1290
1291
1292 /*
1293  * Return an index indicating how much of the available free memory is
1294  * unusable for an allocation of the requested size.
1295  */
1296 static int unusable_free_index(unsigned int order,
1297                                 struct contig_page_info *info)
1298 {
1299         /* No free memory is interpreted as all free memory is unusable */
1300         if (info->free_pages == 0)
1301                 return 1000;
1302
1303         /*
1304          * Index should be a value between 0 and 1. Return a value to 3
1305          * decimal places.
1306          *
1307          * 0 => no fragmentation
1308          * 1 => high fragmentation
1309          */
1310         return div_u64((info->free_pages - (info->free_blocks_suitable << order)) * 1000ULL, info->free_pages);
1311
1312 }
1313
1314 static void unusable_show_print(struct seq_file *m,
1315                                         pg_data_t *pgdat, struct zone *zone)
1316 {
1317         unsigned int order;
1318         int index;
1319         struct contig_page_info info;
1320
1321         seq_printf(m, "Node %d, zone %8s ",
1322                                 pgdat->node_id,
1323                                 zone->name);
1324         for (order = 0; order < MAX_ORDER; ++order) {
1325                 fill_contig_page_info(zone, order, &info);
1326                 index = unusable_free_index(order, &info);
1327                 seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
1328         }
1329
1330         seq_putc(m, '\n');
1331 }
1332
1333 /*
1334  * Display unusable free space index
1335  *
1336  * The unusable free space index measures how much of the available free
1337  * memory cannot be used to satisfy an allocation of a given size and is a
1338  * value between 0 and 1. The higher the value, the more of free memory is
1339  * unusable and by implication, the worse the external fragmentation is. This
1340  * can be expressed as a percentage by multiplying by 100.
1341  */
1342 static int unusable_show(struct seq_file *m, void *arg)
1343 {
1344         pg_data_t *pgdat = (pg_data_t *)arg;
1345
1346         /* check memoryless node */
1347         if (!node_state(pgdat->node_id, N_MEMORY))
1348                 return 0;
1349
1350         walk_zones_in_node(m, pgdat, unusable_show_print);
1351
1352         return 0;
1353 }
1354
1355 static const struct seq_operations unusable_op = {
1356         .start  = frag_start,
1357         .next   = frag_next,
1358         .stop   = frag_stop,
1359         .show   = unusable_show,
1360 };
1361
1362 static int unusable_open(struct inode *inode, struct file *file)
1363 {
1364         return seq_open(file, &unusable_op);
1365 }
1366
1367 static const struct file_operations unusable_file_ops = {
1368         .open           = unusable_open,
1369         .read           = seq_read,
1370         .llseek         = seq_lseek,
1371         .release        = seq_release,
1372 };
1373
1374 static void extfrag_show_print(struct seq_file *m,
1375                                         pg_data_t *pgdat, struct zone *zone)
1376 {
1377         unsigned int order;
1378         int index;
1379
1380         /* Alloc on stack as interrupts are disabled for zone walk */
1381         struct contig_page_info info;
1382
1383         seq_printf(m, "Node %d, zone %8s ",
1384                                 pgdat->node_id,
1385                                 zone->name);
1386         for (order = 0; order < MAX_ORDER; ++order) {
1387                 fill_contig_page_info(zone, order, &info);
1388                 index = __fragmentation_index(order, &info);
1389                 seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
1390         }
1391
1392         seq_putc(m, '\n');
1393 }
1394
1395 /*
1396  * Display fragmentation index for orders that allocations would fail for
1397  */
1398 static int extfrag_show(struct seq_file *m, void *arg)
1399 {
1400         pg_data_t *pgdat = (pg_data_t *)arg;
1401
1402         walk_zones_in_node(m, pgdat, extfrag_show_print);
1403
1404         return 0;
1405 }
1406
1407 static const struct seq_operations extfrag_op = {
1408         .start  = frag_start,
1409         .next   = frag_next,
1410         .stop   = frag_stop,
1411         .show   = extfrag_show,
1412 };
1413
1414 static int extfrag_open(struct inode *inode, struct file *file)
1415 {
1416         return seq_open(file, &extfrag_op);
1417 }
1418
1419 static const struct file_operations extfrag_file_ops = {
1420         .open           = extfrag_open,
1421         .read           = seq_read,
1422         .llseek         = seq_lseek,
1423         .release        = seq_release,
1424 };
1425
1426 static int __init extfrag_debug_init(void)
1427 {
1428         struct dentry *extfrag_debug_root;
1429
1430         extfrag_debug_root = debugfs_create_dir("extfrag", NULL);
1431         if (!extfrag_debug_root)
1432                 return -ENOMEM;
1433
1434         if (!debugfs_create_file("unusable_index", 0444,
1435                         extfrag_debug_root, NULL, &unusable_file_ops))
1436                 goto fail;
1437
1438         if (!debugfs_create_file("extfrag_index", 0444,
1439                         extfrag_debug_root, NULL, &extfrag_file_ops))
1440                 goto fail;
1441
1442         return 0;
1443 fail:
1444         debugfs_remove_recursive(extfrag_debug_root);
1445         return -ENOMEM;
1446 }
1447
1448 module_init(extfrag_debug_init);
1449 #endif