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 one cpu.
 419  *
 420  * The cpu specified must be either the current cpu or a processor that
 421  * is not online. If it is the current cpu then the execution thread must
 422  * be pinned to the current cpu.
 423  *
 424  * Note that refresh_cpu_vm_stats strives to only access
 425  * node local memory. The per cpu pagesets on remote zones are placed
 426  * in the memory local to the processor using that pageset. So the
 427  * loop over all zones will access a series of cachelines local to
 428  * the processor.
 429  *
 430  * The call to zone_page_state_add updates the cachelines with the
 431  * statistics in the remote zone struct as well as the global cachelines
 432  * with the global counters. These could cause remote node cache line
 433  * bouncing and will have to be only done when necessary.
 434  */
 435 void refresh_cpu_vm_stats(int cpu)
 436 {
 437         struct zone *zone;
 438         int i;
 439         int global_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
 440
 441         for_each_populated_zone(zone) {
 442                 struct per_cpu_pageset *p;
 443
 444                 p = per_cpu_ptr(zone->pageset, cpu);
 445
 446                 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 447                         if (p->vm_stat_diff[i]) {
 448                                 unsigned long flags;
 449                                 int v;
 450
 451                                 local_irq_save(flags);
 452                                 v = p->vm_stat_diff[i];
 453                                 p->vm_stat_diff[i] = 0;
 454                                 local_irq_restore(flags);
 455                                 atomic_long_add(v, &zone->vm_stat[i]);
 456                                 global_diff[i] += v;
 457 #ifdef CONFIG_NUMA
 458                                 /* 3 seconds idle till flush */
 459                                 p->expire = 3;
 460 #endif
 461                         }
 462                 cond_resched();
 463 #ifdef CONFIG_NUMA
 464                 /*
 465                  * Deal with draining the remote pageset of this
 466                  * processor
 467                  *
 468                  * Check if there are pages remaining in this pageset
 469                  * if not then there is nothing to expire.
 470                  */
 471                 if (!p->expire || !p->pcp.count)
 472                         continue;
 473
 474                 /*
 475                  * We never drain zones local to this processor.
 476                  */
 477                 if (zone_to_nid(zone) == numa_node_id()) {
 478                         p->expire = 0;
 479                         continue;
 480                 }
 481
 482                 p->expire--;
 483                 if (p->expire)
 484                         continue;
 485
 486                 if (p->pcp.count)
 487                         drain_zone_pages(zone, &p->pcp);
 488 #endif
 489         }
 490
 491         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 492                 if (global_diff[i])
 493                         atomic_long_add(global_diff[i], &vm_stat[i]);
 494 }
 495
 496 /*
 497  * this is only called if !populated_zone(zone), which implies no other users of
 498  * pset->vm_stat_diff[] exsist.
 499  */
 500 void drain_zonestat(struct zone *zone, struct per_cpu_pageset *pset)
 501 {
 502         int i;
 503
 504         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 505                 if (pset->vm_stat_diff[i]) {
 506                         int v = pset->vm_stat_diff[i];
 507                         pset->vm_stat_diff[i] = 0;
 508                         atomic_long_add(v, &zone->vm_stat[i]);
 509                         atomic_long_add(v, &vm_stat[i]);
 510                 }
 511 }
 512 #endif
 513
 514 #ifdef CONFIG_NUMA
 515 /*
 516  * zonelist = the list of zones passed to the allocator
 517  * z        = the zone from which the allocation occurred.
 518  *
 519  * Must be called with interrupts disabled.
 520  *
 521  * When __GFP_OTHER_NODE is set assume the node of the preferred
 522  * zone is the local node. This is useful for daemons who allocate
 523  * memory on behalf of other processes.
 524  */
 525 void zone_statistics(struct zone *preferred_zone, struct zone *z, gfp_t flags)
 526 {
 527         if (z->zone_pgdat == preferred_zone->zone_pgdat) {
 528                 __inc_zone_state(z, NUMA_HIT);
 529         } else {
 530                 __inc_zone_state(z, NUMA_MISS);
 531                 __inc_zone_state(preferred_zone, NUMA_FOREIGN);
 532         }
 533         if (z->node == ((flags & __GFP_OTHER_NODE) ?
 534                         preferred_zone->node : numa_node_id()))
 535                 __inc_zone_state(z, NUMA_LOCAL);
 536         else
 537                 __inc_zone_state(z, NUMA_OTHER);
 538 }
 539 #endif
 540
 541 #ifdef CONFIG_COMPACTION
 542
 543 struct contig_page_info {
 544         unsigned long free_pages;
 545         unsigned long free_blocks_total;
 546         unsigned long free_blocks_suitable;
 547 };
 548
 549 /*
 550  * Calculate the number of free pages in a zone, how many contiguous
 551  * pages are free and how many are large enough to satisfy an allocation of
 552  * the target size. Note that this function makes no attempt to estimate
 553  * how many suitable free blocks there *might* be if MOVABLE pages were
 554  * migrated. Calculating that is possible, but expensive and can be
 555  * figured out from userspace
 556  */
 557 static void fill_contig_page_info(struct zone *zone,
 558                                 unsigned int suitable_order,
 559                                 struct contig_page_info *info)
 560 {
 561         unsigned int order;
 562
 563         info->free_pages = 0;
 564         info->free_blocks_total = 0;
 565         info->free_blocks_suitable = 0;
 566
 567         for (order = 0; order < MAX_ORDER; order++) {
 568                 unsigned long blocks;
 569
 570                 /* Count number of free blocks */
 571                 blocks = zone->free_area[order].nr_free;
 572                 info->free_blocks_total += blocks;
 573
 574                 /* Count free base pages */
 575                 info->free_pages += blocks << order;
 576
 577                 /* Count the suitable free blocks */
 578                 if (order >= suitable_order)
 579                         info->free_blocks_suitable += blocks <<
 580                                                 (order - suitable_order);
 581         }
 582 }
 583
 584 /*
 585  * A fragmentation index only makes sense if an allocation of a requested
 586  * size would fail. If that is true, the fragmentation index indicates
 587  * whether external fragmentation or a lack of memory was the problem.
 588  * The value can be used to determine if page reclaim or compaction
 589  * should be used
 590  */
 591 static int __fragmentation_index(unsigned int order, struct contig_page_info *info)
 592 {
 593         unsigned long requested = 1UL << order;
 594
 595         if (!info->free_blocks_total)
 596                 return 0;
 597
 598         /* Fragmentation index only makes sense when a request would fail */
 599         if (info->free_blocks_suitable)
 600                 return -1000;
 601
 602         /*
 603          * Index is between 0 and 1 so return within 3 decimal places
 604          *
 605          * 0 => allocation would fail due to lack of memory
 606          * 1 => allocation would fail due to fragmentation
 607          */
 608         return 1000 - div_u64( (1000+(div_u64(info->free_pages * 1000ULL, requested))), info->free_blocks_total);
 609 }
 610
 611 /* Same as __fragmentation index but allocs contig_page_info on stack */
 612 int fragmentation_index(struct zone *zone, unsigned int order)
 613 {
 614         struct contig_page_info info;
 615
 616         fill_contig_page_info(zone, order, &info);
 617         return __fragmentation_index(order, &info);
 618 }
 619 #endif
 620
 621 #if defined(CONFIG_PROC_FS) || defined(CONFIG_COMPACTION)
 622 #include <linux/proc_fs.h>
 623 #include <linux/seq_file.h>
 624
 625 static char * const migratetype_names[MIGRATE_TYPES] = {
 626         "Unmovable",
 627         "Reclaimable",
 628         "Movable",
 629         "Reserve",
 630 #ifdef CONFIG_CMA
 631         "CMA",
 632 #endif
 633 #ifdef CONFIG_MEMORY_ISOLATION
 634         "Isolate",
 635 #endif
 636 };
 637
 638 static void *frag_start(struct seq_file *m, loff_t *pos)
 639 {
 640         pg_data_t *pgdat;
 641         loff_t node = *pos;
 642         for (pgdat = first_online_pgdat();
 643              pgdat && node;
 644              pgdat = next_online_pgdat(pgdat))
 645                 --node;
 646
 647         return pgdat;
 648 }
 649
 650 static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
 651 {
 652         pg_data_t *pgdat = (pg_data_t *)arg;
 653
 654         (*pos)++;
 655         return next_online_pgdat(pgdat);
 656 }
 657
 658 static void frag_stop(struct seq_file *m, void *arg)
 659 {
 660 }
 661
 662 /* Walk all the zones in a node and print using a callback */
 663 static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat,
 664                 void (*print)(struct seq_file *m, pg_data_t *, struct zone *))
 665 {
 666         struct zone *zone;
 667         struct zone *node_zones = pgdat->node_zones;
 668         unsigned long flags;
 669
 670         for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
 671                 if (!populated_zone(zone))
 672                         continue;
 673
 674                 spin_lock_irqsave(&zone->lock, flags);
 675                 print(m, pgdat, zone);
 676                 spin_unlock_irqrestore(&zone->lock, flags);
 677         }
 678 }
 679 #endif
 680
 681 #if defined(CONFIG_PROC_FS) || defined(CONFIG_SYSFS) || defined(CONFIG_NUMA)
 682 #ifdef CONFIG_ZONE_DMA
 683 #define TEXT_FOR_DMA(xx) xx "_dma",
 684 #else
 685 #define TEXT_FOR_DMA(xx)
 686 #endif
 687
 688 #ifdef CONFIG_ZONE_DMA32
 689 #define TEXT_FOR_DMA32(xx) xx "_dma32",
 690 #else
 691 #define TEXT_FOR_DMA32(xx)
 692 #endif
 693
 694 #ifdef CONFIG_HIGHMEM
 695 #define TEXT_FOR_HIGHMEM(xx) xx "_high",
 696 #else
 697 #define TEXT_FOR_HIGHMEM(xx)
 698 #endif
 699
 700 #define TEXTS_FOR_ZONES(xx) TEXT_FOR_DMA(xx) TEXT_FOR_DMA32(xx) xx "_normal", \
 701                                         TEXT_FOR_HIGHMEM(xx) xx "_movable",
 702
 703 const char * const vmstat_text[] = {
 704         /* Zoned VM counters */
 705         "nr_free_pages",
 706         "nr_inactive_anon",
 707         "nr_active_anon",
 708         "nr_inactive_file",
 709         "nr_active_file",
 710         "nr_unevictable",
 711         "nr_mlock",
 712         "nr_anon_pages",
 713         "nr_mapped",
 714         "nr_file_pages",
 715         "nr_dirty",
 716         "nr_writeback",
 717         "nr_slab_reclaimable",
 718         "nr_slab_unreclaimable",
 719         "nr_page_table_pages",
 720         "nr_kernel_stack",
 721         "nr_unstable",
 722         "nr_bounce",
 723         "nr_vmscan_write",
 724         "nr_vmscan_immediate_reclaim",
 725         "nr_writeback_temp",
 726         "nr_isolated_anon",
 727         "nr_isolated_file",
 728         "nr_shmem",
 729         "nr_dirtied",
 730         "nr_written",
 731
 732 #ifdef CONFIG_NUMA
 733         "numa_hit",
 734         "numa_miss",
 735         "numa_foreign",
 736         "numa_interleave",
 737         "numa_local",
 738         "numa_other",
 739 #endif
 740         "nr_anon_transparent_hugepages",
 741         "nr_free_cma",
 742         "nr_dirty_threshold",
 743         "nr_dirty_background_threshold",
 744
 745 #ifdef CONFIG_VM_EVENT_COUNTERS
 746         "pgpgin",
 747         "pgpgout",
 748         "pswpin",
 749         "pswpout",
 750
 751         TEXTS_FOR_ZONES("pgalloc")
 752
 753         "pgfree",
 754         "pgactivate",
 755         "pgdeactivate",
 756
 757         "pgfault",
 758         "pgmajfault",
 759
 760         TEXTS_FOR_ZONES("pgrefill")
 761         TEXTS_FOR_ZONES("pgsteal_kswapd")
 762         TEXTS_FOR_ZONES("pgsteal_direct")
 763         TEXTS_FOR_ZONES("pgscan_kswapd")
 764         TEXTS_FOR_ZONES("pgscan_direct")
 765         "pgscan_direct_throttle",
 766
 767 #ifdef CONFIG_NUMA
 768         "zone_reclaim_failed",
 769 #endif
 770         "pginodesteal",
 771         "slabs_scanned",
 772         "kswapd_inodesteal",
 773         "kswapd_low_wmark_hit_quickly",
 774         "kswapd_high_wmark_hit_quickly",
 775         "pageoutrun",
 776         "allocstall",
 777
 778         "pgrotated",
 779
 780 #ifdef CONFIG_NUMA_BALANCING
 781         "numa_pte_updates",
 782         "numa_huge_pte_updates",
 783         "numa_hint_faults",
 784         "numa_hint_faults_local",
 785         "numa_pages_migrated",
 786 #endif
 787 #ifdef CONFIG_MIGRATION
 788         "pgmigrate_success",
 789         "pgmigrate_fail",
 790 #endif
 791 #ifdef CONFIG_COMPACTION
 792         "compact_migrate_scanned",
 793         "compact_free_scanned",
 794         "compact_isolated",
 795         "compact_stall",
 796         "compact_fail",
 797         "compact_success",
 798 #endif
 799
 800 #ifdef CONFIG_HUGETLB_PAGE
 801         "htlb_buddy_alloc_success",
 802         "htlb_buddy_alloc_fail",
 803 #endif
 804         "unevictable_pgs_culled",
 805         "unevictable_pgs_scanned",
 806         "unevictable_pgs_rescued",
 807         "unevictable_pgs_mlocked",
 808         "unevictable_pgs_munlocked",
 809         "unevictable_pgs_cleared",
 810         "unevictable_pgs_stranded",
 811
 812 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 813         "thp_fault_alloc",
 814         "thp_fault_fallback",
 815         "thp_collapse_alloc",
 816         "thp_collapse_alloc_failed",
 817         "thp_split",
 818         "thp_zero_page_alloc",
 819         "thp_zero_page_alloc_failed",
 820 #endif
 821
 822 #endif /* CONFIG_VM_EVENTS_COUNTERS */
 823 };
 824 #endif /* CONFIG_PROC_FS || CONFIG_SYSFS || CONFIG_NUMA */
 825
 826
 827 #ifdef CONFIG_PROC_FS
 828 static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,
 829                                                 struct zone *zone)
 830 {
 831         int order;
 832
 833         seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
 834         for (order = 0; order < MAX_ORDER; ++order)
 835                 seq_printf(m, "%6lu ", zone->free_area[order].nr_free);
 836         seq_putc(m, '\n');
 837 }
 838
 839 /*
 840  * This walks the free areas for each zone.
 841  */
 842 static int frag_show(struct seq_file *m, void *arg)
 843 {
 844         pg_data_t *pgdat = (pg_data_t *)arg;
 845         walk_zones_in_node(m, pgdat, frag_show_print);
 846         return 0;
 847 }
 848
 849 static void pagetypeinfo_showfree_print(struct seq_file *m,
 850                                         pg_data_t *pgdat, struct zone *zone)
 851 {
 852         int order, mtype;
 853
 854         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++) {
 855                 seq_printf(m, "Node %4d, zone %8s, type %12s ",
 856                                         pgdat->node_id,
 857                                         zone->name,
 858                                         migratetype_names[mtype]);
 859                 for (order = 0; order < MAX_ORDER; ++order) {
 860                         unsigned long freecount = 0;
 861                         struct free_area *area;
 862                         struct list_head *curr;
 863
 864                         area = &(zone->free_area[order]);
 865
 866                         list_for_each(curr, &area->free_list[mtype])
 867                                 freecount++;
 868                         seq_printf(m, "%6lu ", freecount);
 869                 }
 870                 seq_putc(m, '\n');
 871         }
 872 }
 873
 874 /* Print out the free pages at each order for each migatetype */
 875 static int pagetypeinfo_showfree(struct seq_file *m, void *arg)
 876 {
 877         int order;
 878         pg_data_t *pgdat = (pg_data_t *)arg;
 879
 880         /* Print header */
 881         seq_printf(m, "%-43s ", "Free pages count per migrate type at order");
 882         for (order = 0; order < MAX_ORDER; ++order)
 883                 seq_printf(m, "%6d ", order);
 884         seq_putc(m, '\n');
 885
 886         walk_zones_in_node(m, pgdat, pagetypeinfo_showfree_print);
 887
 888         return 0;
 889 }
 890
 891 static void pagetypeinfo_showblockcount_print(struct seq_file *m,
 892                                         pg_data_t *pgdat, struct zone *zone)
 893 {
 894         int mtype;
 895         unsigned long pfn;
 896         unsigned long start_pfn = zone->zone_start_pfn;
 897         unsigned long end_pfn = zone_end_pfn(zone);
 898         unsigned long count[MIGRATE_TYPES] = { 0, };
 899
 900         for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
 901                 struct page *page;
 902
 903                 if (!pfn_valid(pfn))
 904                         continue;
 905
 906                 page = pfn_to_page(pfn);
 907
 908                 /* Watch for unexpected holes punched in the memmap */
 909                 if (!memmap_valid_within(pfn, page, zone))
 910                         continue;
 911
 912                 mtype = get_pageblock_migratetype(page);
 913
 914                 if (mtype < MIGRATE_TYPES)
 915                         count[mtype]++;
 916         }
 917
 918         /* Print counts */
 919         seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
 920         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
 921                 seq_printf(m, "%12lu ", count[mtype]);
 922         seq_putc(m, '\n');
 923 }
 924
 925 /* Print out the free pages at each order for each migratetype */
 926 static int pagetypeinfo_showblockcount(struct seq_file *m, void *arg)
 927 {
 928         int mtype;
 929         pg_data_t *pgdat = (pg_data_t *)arg;
 930
 931         seq_printf(m, "\n%-23s", "Number of blocks type ");
 932         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
 933                 seq_printf(m, "%12s ", migratetype_names[mtype]);
 934         seq_putc(m, '\n');
 935         walk_zones_in_node(m, pgdat, pagetypeinfo_showblockcount_print);
 936
 937         return 0;
 938 }
 939
 940 /*
 941  * This prints out statistics in relation to grouping pages by mobility.
 942  * It is expensive to collect so do not constantly read the file.
 943  */
 944 static int pagetypeinfo_show(struct seq_file *m, void *arg)
 945 {
 946         pg_data_t *pgdat = (pg_data_t *)arg;
 947
 948         /* check memoryless node */
 949         if (!node_state(pgdat->node_id, N_MEMORY))
 950                 return 0;
 951
 952         seq_printf(m, "Page block order: %d\n", pageblock_order);
 953         seq_printf(m, "Pages per block:  %lu\n", pageblock_nr_pages);
 954         seq_putc(m, '\n');
 955         pagetypeinfo_showfree(m, pgdat);
 956         pagetypeinfo_showblockcount(m, pgdat);
 957
 958         return 0;
 959 }
 960
 961 static const struct seq_operations fragmentation_op = {
 962         .start  = frag_start,
 963         .next   = frag_next,
 964         .stop   = frag_stop,
 965         .show   = frag_show,
 966 };
 967
 968 static int fragmentation_open(struct inode *inode, struct file *file)
 969 {
 970         return seq_open(file, &fragmentation_op);
 971 }
 972
 973 static const struct file_operations fragmentation_file_operations = {
 974         .open           = fragmentation_open,
 975         .read           = seq_read,
 976         .llseek         = seq_lseek,
 977         .release        = seq_release,
 978 };
 979
 980 static const struct seq_operations pagetypeinfo_op = {
 981         .start  = frag_start,
 982         .next   = frag_next,
 983         .stop   = frag_stop,
 984         .show   = pagetypeinfo_show,
 985 };
 986
 987 static int pagetypeinfo_open(struct inode *inode, struct file *file)
 988 {
 989         return seq_open(file, &pagetypeinfo_op);
 990 }
 991
 992 static const struct file_operations pagetypeinfo_file_ops = {
 993         .open           = pagetypeinfo_open,
 994         .read           = seq_read,
 995         .llseek         = seq_lseek,
 996         .release        = seq_release,
 997 };
 998
 999 static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
1000                                                         struct zone *zone)
1001 {
1002         int i;
1003         seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name);
1004         seq_printf(m,
1005                    "\n  pages free     %lu"
1006                    "\n        min      %lu"
1007                    "\n        low      %lu"
1008                    "\n        high     %lu"
1009                    "\n        scanned  %lu"
1010                    "\n        spanned  %lu"
1011                    "\n        present  %lu"
1012                    "\n        managed  %lu",
1013                    zone_page_state(zone, NR_FREE_PAGES),
1014                    min_wmark_pages(zone),
1015                    low_wmark_pages(zone),
1016                    high_wmark_pages(zone),
1017                    zone->pages_scanned,
1018                    zone->spanned_pages,
1019                    zone->present_pages,
1020                    zone->managed_pages);
1021
1022         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
1023                 seq_printf(m, "\n    %-12s %lu", vmstat_text[i],
1024                                 zone_page_state(zone, i));
1025
1026         seq_printf(m,
1027                    "\n        protection: (%lu",
1028                    zone->lowmem_reserve[0]);
1029         for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++)
1030                 seq_printf(m, ", %lu", zone->lowmem_reserve[i]);
1031         seq_printf(m,
1032                    ")"
1033                    "\n  pagesets");
1034         for_each_online_cpu(i) {
1035                 struct per_cpu_pageset *pageset;
1036
1037                 pageset = per_cpu_ptr(zone->pageset, i);
1038                 seq_printf(m,
1039                            "\n    cpu: %i"
1040                            "\n              count: %i"
1041                            "\n              high:  %i"
1042                            "\n              batch: %i",
1043                            i,
1044                            pageset->pcp.count,
1045                            pageset->pcp.high,
1046                            pageset->pcp.batch);
1047 #ifdef CONFIG_SMP
1048                 seq_printf(m, "\n  vm stats threshold: %d",
1049                                 pageset->stat_threshold);
1050 #endif
1051         }
1052         seq_printf(m,
1053                    "\n  all_unreclaimable: %u"
1054                    "\n  start_pfn:         %lu"
1055                    "\n  inactive_ratio:    %u",
1056                    zone->all_unreclaimable,
1057                    zone->zone_start_pfn,
1058                    zone->inactive_ratio);
1059         seq_putc(m, '\n');
1060 }
1061
1062 /*
1063  * Output information about zones in @pgdat.
1064  */
1065 static int zoneinfo_show(struct seq_file *m, void *arg)
1066 {
1067         pg_data_t *pgdat = (pg_data_t *)arg;
1068         walk_zones_in_node(m, pgdat, zoneinfo_show_print);
1069         return 0;
1070 }
1071
1072 static const struct seq_operations zoneinfo_op = {
1073         .start  = frag_start, /* iterate over all zones. The same as in
1074                                * fragmentation. */
1075         .next   = frag_next,
1076         .stop   = frag_stop,
1077         .show   = zoneinfo_show,
1078 };
1079
1080 static int zoneinfo_open(struct inode *inode, struct file *file)
1081 {
1082         return seq_open(file, &zoneinfo_op);
1083 }
1084
1085 static const struct file_operations proc_zoneinfo_file_operations = {
1086         .open           = zoneinfo_open,
1087         .read           = seq_read,
1088         .llseek         = seq_lseek,
1089         .release        = seq_release,
1090 };
1091
1092 enum writeback_stat_item {
1093         NR_DIRTY_THRESHOLD,
1094         NR_DIRTY_BG_THRESHOLD,
1095         NR_VM_WRITEBACK_STAT_ITEMS,
1096 };
1097
1098 static void *vmstat_start(struct seq_file *m, loff_t *pos)
1099 {
1100         unsigned long *v;
1101         int i, stat_items_size;
1102
1103         if (*pos >= ARRAY_SIZE(vmstat_text))
1104                 return NULL;
1105         stat_items_size = NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long) +
1106                           NR_VM_WRITEBACK_STAT_ITEMS * sizeof(unsigned long);
1107
1108 #ifdef CONFIG_VM_EVENT_COUNTERS
1109         stat_items_size += sizeof(struct vm_event_state);
1110 #endif
1111
1112         v = kmalloc(stat_items_size, GFP_KERNEL);
1113         m->private = v;
1114         if (!v)
1115                 return ERR_PTR(-ENOMEM);
1116         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
1117                 v[i] = global_page_state(i);
1118         v += NR_VM_ZONE_STAT_ITEMS;
1119
1120         global_dirty_limits(v + NR_DIRTY_BG_THRESHOLD,
1121                             v + NR_DIRTY_THRESHOLD);
1122         v += NR_VM_WRITEBACK_STAT_ITEMS;
1123
1124 #ifdef CONFIG_VM_EVENT_COUNTERS
1125         all_vm_events(v);
1126         v[PGPGIN] /= 2;         /* sectors -> kbytes */
1127         v[PGPGOUT] /= 2;
1128 #endif
1129         return (unsigned long *)m->private + *pos;
1130 }
1131
1132 static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)
1133 {
1134         (*pos)++;
1135         if (*pos >= ARRAY_SIZE(vmstat_text))
1136                 return NULL;
1137         return (unsigned long *)m->private + *pos;
1138 }
1139
1140 static int vmstat_show(struct seq_file *m, void *arg)
1141 {
1142         unsigned long *l = arg;
1143         unsigned long off = l - (unsigned long *)m->private;
1144
1145         seq_printf(m, "%s %lu\n", vmstat_text[off], *l);
1146         return 0;
1147 }
1148
1149 static void vmstat_stop(struct seq_file *m, void *arg)
1150 {
1151         kfree(m->private);
1152         m->private = NULL;
1153 }
1154
1155 static const struct seq_operations vmstat_op = {
1156         .start  = vmstat_start,
1157         .next   = vmstat_next,
1158         .stop   = vmstat_stop,
1159         .show   = vmstat_show,
1160 };
1161
1162 static int vmstat_open(struct inode *inode, struct file *file)
1163 {
1164         return seq_open(file, &vmstat_op);
1165 }
1166
1167 static const struct file_operations proc_vmstat_file_operations = {
1168         .open           = vmstat_open,
1169         .read           = seq_read,
1170         .llseek         = seq_lseek,
1171         .release        = seq_release,
1172 };
1173 #endif /* CONFIG_PROC_FS */
1174
1175 #ifdef CONFIG_SMP
1176 static DEFINE_PER_CPU(struct delayed_work, vmstat_work);
1177 int sysctl_stat_interval __read_mostly = HZ;
1178
1179 static void vmstat_update(struct work_struct *w)
1180 {
1181         refresh_cpu_vm_stats(smp_processor_id());
1182         schedule_delayed_work(&__get_cpu_var(vmstat_work),
1183                 round_jiffies_relative(sysctl_stat_interval));
1184 }
1185
1186 static void __cpuinit start_cpu_timer(int cpu)
1187 {
1188         struct delayed_work *work = &per_cpu(vmstat_work, cpu);
1189
1190         INIT_DEFERRABLE_WORK(work, vmstat_update);
1191         schedule_delayed_work_on(cpu, work, __round_jiffies_relative(HZ, cpu));
1192 }
1193
1194 /*
1195  * Use the cpu notifier to insure that the thresholds are recalculated
1196  * when necessary.
1197  */
1198 static int __cpuinit vmstat_cpuup_callback(struct notifier_block *nfb,
1199                 unsigned long action,
1200                 void *hcpu)
1201 {
1202         long cpu = (long)hcpu;
1203
1204         switch (action) {
1205         case CPU_ONLINE:
1206         case CPU_ONLINE_FROZEN:
1207                 refresh_zone_stat_thresholds();
1208                 start_cpu_timer(cpu);
1209                 node_set_state(cpu_to_node(cpu), N_CPU);
1210                 break;
1211         case CPU_DOWN_PREPARE:
1212         case CPU_DOWN_PREPARE_FROZEN:
1213                 cancel_delayed_work_sync(&per_cpu(vmstat_work, cpu));
1214                 per_cpu(vmstat_work, cpu).work.func = NULL;
1215                 break;
1216         case CPU_DOWN_FAILED:
1217         case CPU_DOWN_FAILED_FROZEN:
1218                 start_cpu_timer(cpu);
1219                 break;
1220         case CPU_DEAD:
1221         case CPU_DEAD_FROZEN:
1222                 refresh_zone_stat_thresholds();
1223                 break;
1224         default:
1225                 break;
1226         }
1227         return NOTIFY_OK;
1228 }
1229
1230 static struct notifier_block __cpuinitdata vmstat_notifier =
1231         { &vmstat_cpuup_callback, NULL, 0 };
1232 #endif
1233
1234 static int __init setup_vmstat(void)
1235 {
1236 #ifdef CONFIG_SMP
1237         int cpu;
1238
1239         register_cpu_notifier(&vmstat_notifier);
1240
1241         for_each_online_cpu(cpu)
1242                 start_cpu_timer(cpu);
1243 #endif
1244 #ifdef CONFIG_PROC_FS
1245         proc_create("buddyinfo", S_IRUGO, NULL, &fragmentation_file_operations);
1246         proc_create("pagetypeinfo", S_IRUGO, NULL, &pagetypeinfo_file_ops);
1247         proc_create("vmstat", S_IRUGO, NULL, &proc_vmstat_file_operations);
1248         proc_create("zoneinfo", S_IRUGO, NULL, &proc_zoneinfo_file_operations);
1249 #endif
1250         return 0;
1251 }
1252 module_init(setup_vmstat)
1253
1254 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)
1255 #include <linux/debugfs.h>
1256
1257
1258 /*
1259  * Return an index indicating how much of the available free memory is
1260  * unusable for an allocation of the requested size.
1261  */
1262 static int unusable_free_index(unsigned int order,
1263                                 struct contig_page_info *info)
1264 {
1265         /* No free memory is interpreted as all free memory is unusable */
1266         if (info->free_pages == 0)
1267                 return 1000;
1268
1269         /*
1270          * Index should be a value between 0 and 1. Return a value to 3
1271          * decimal places.
1272          *
1273          * 0 => no fragmentation
1274          * 1 => high fragmentation
1275          */
1276         return div_u64((info->free_pages - (info->free_blocks_suitable << order)) * 1000ULL, info->free_pages);
1277
1278 }
1279
1280 static void unusable_show_print(struct seq_file *m,
1281                                         pg_data_t *pgdat, struct zone *zone)
1282 {
1283         unsigned int order;
1284         int index;
1285         struct contig_page_info info;
1286
1287         seq_printf(m, "Node %d, zone %8s ",
1288                                 pgdat->node_id,
1289                                 zone->name);
1290         for (order = 0; order < MAX_ORDER; ++order) {
1291                 fill_contig_page_info(zone, order, &info);
1292                 index = unusable_free_index(order, &info);
1293                 seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
1294         }
1295
1296         seq_putc(m, '\n');
1297 }
1298
1299 /*
1300  * Display unusable free space index
1301  *
1302  * The unusable free space index measures how much of the available free
1303  * memory cannot be used to satisfy an allocation of a given size and is a
1304  * value between 0 and 1. The higher the value, the more of free memory is
1305  * unusable and by implication, the worse the external fragmentation is. This
1306  * can be expressed as a percentage by multiplying by 100.
1307  */
1308 static int unusable_show(struct seq_file *m, void *arg)
1309 {
1310         pg_data_t *pgdat = (pg_data_t *)arg;
1311
1312         /* check memoryless node */
1313         if (!node_state(pgdat->node_id, N_MEMORY))
1314                 return 0;
1315
1316         walk_zones_in_node(m, pgdat, unusable_show_print);
1317
1318         return 0;
1319 }
1320
1321 static const struct seq_operations unusable_op = {
1322         .start  = frag_start,
1323         .next   = frag_next,
1324         .stop   = frag_stop,
1325         .show   = unusable_show,
1326 };
1327
1328 static int unusable_open(struct inode *inode, struct file *file)
1329 {
1330         return seq_open(file, &unusable_op);
1331 }
1332
1333 static const struct file_operations unusable_file_ops = {
1334         .open           = unusable_open,
1335         .read           = seq_read,
1336         .llseek         = seq_lseek,
1337         .release        = seq_release,
1338 };
1339
1340 static void extfrag_show_print(struct seq_file *m,
1341                                         pg_data_t *pgdat, struct zone *zone)
1342 {
1343         unsigned int order;
1344         int index;
1345
1346         /* Alloc on stack as interrupts are disabled for zone walk */
1347         struct contig_page_info info;
1348
1349         seq_printf(m, "Node %d, zone %8s ",
1350                                 pgdat->node_id,
1351                                 zone->name);
1352         for (order = 0; order < MAX_ORDER; ++order) {
1353                 fill_contig_page_info(zone, order, &info);
1354                 index = __fragmentation_index(order, &info);
1355                 seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
1356         }
1357
1358         seq_putc(m, '\n');
1359 }
1360
1361 /*
1362  * Display fragmentation index for orders that allocations would fail for
1363  */
1364 static int extfrag_show(struct seq_file *m, void *arg)
1365 {
1366         pg_data_t *pgdat = (pg_data_t *)arg;
1367
1368         walk_zones_in_node(m, pgdat, extfrag_show_print);
1369
1370         return 0;
1371 }
1372
1373 static const struct seq_operations extfrag_op = {
1374         .start  = frag_start,
1375         .next   = frag_next,
1376         .stop   = frag_stop,
1377         .show   = extfrag_show,
1378 };
1379
1380 static int extfrag_open(struct inode *inode, struct file *file)
1381 {
1382         return seq_open(file, &extfrag_op);
1383 }
1384
1385 static const struct file_operations extfrag_file_ops = {
1386         .open           = extfrag_open,
1387         .read           = seq_read,
1388         .llseek         = seq_lseek,
1389         .release        = seq_release,
1390 };
1391
1392 static int __init extfrag_debug_init(void)
1393 {
1394         struct dentry *extfrag_debug_root;
1395
1396         extfrag_debug_root = debugfs_create_dir("extfrag", NULL);
1397         if (!extfrag_debug_root)
1398                 return -ENOMEM;
1399
1400         if (!debugfs_create_file("unusable_index", 0444,
1401                         extfrag_debug_root, NULL, &unusable_file_ops))
1402                 goto fail;
1403
1404         if (!debugfs_create_file("extfrag_index", 0444,
1405                         extfrag_debug_root, NULL, &extfrag_file_ops))
1406                 goto fail;
1407
1408         return 0;
1409 fail:
1410         debugfs_remove_recursive(extfrag_debug_root);
1411         return -ENOMEM;
1412 }
1413
1414 module_init(extfrag_debug_init);
1415 #endif