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