Pileus Git - ~andy/linux/blob - 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 static inline void fold_diff(int *diff)
 421 {
 422         int i;
 423
 424         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 425                 if (diff[i])
 426                         atomic_long_add(diff[i], &vm_stat[i]);
 427 }
 428
 429 /*
 430  * Update the zone counters for the current cpu.
 431  *
 432  * Note that refresh_cpu_vm_stats strives to only access
 433  * node local memory. The per cpu pagesets on remote zones are placed
 434  * in the memory local to the processor using that pageset. So the
 435  * loop over all zones will access a series of cachelines local to
 436  * the processor.
 437  *
 438  * The call to zone_page_state_add updates the cachelines with the
 439  * statistics in the remote zone struct as well as the global cachelines
 440  * with the global counters. These could cause remote node cache line
 441  * bouncing and will have to be only done when necessary.
 442  */
 443 static void refresh_cpu_vm_stats(void)
 444 {
 445         struct zone *zone;
 446         int i;
 447         int global_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
 448
 449         for_each_populated_zone(zone) {
 450                 struct per_cpu_pageset __percpu *p = zone->pageset;
 451
 452                 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
 453                         int v;
 454
 455                         v = this_cpu_xchg(p->vm_stat_diff[i], 0);
 456                         if (v) {
 457
 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                                 __this_cpu_write(p->expire, 3);
 463 #endif
 464                         }
 465                 }
 466                 cond_resched();
 467 #ifdef CONFIG_NUMA
 468                 /*
 469                  * Deal with draining the remote pageset of this
 470                  * processor
 471                  *
 472                  * Check if there are pages remaining in this pageset
 473                  * if not then there is nothing to expire.
 474                  */
 475                 if (!__this_cpu_read(p->expire) ||
 476                                !__this_cpu_read(p->pcp.count))
 477                         continue;
 478
 479                 /*
 480                  * We never drain zones local to this processor.
 481                  */
 482                 if (zone_to_nid(zone) == numa_node_id()) {
 483                         __this_cpu_write(p->expire, 0);
 484                         continue;
 485                 }
 486
 487
 488                 if (__this_cpu_dec_return(p->expire))
 489                         continue;
 490
 491                 if (__this_cpu_read(p->pcp.count))
 492                         drain_zone_pages(zone, __this_cpu_ptr(&p->pcp));
 493 #endif
 494         }
 495         fold_diff(global_diff);
 496 }
 497
 498 /*
 499  * Fold the data for an offline cpu into the global array.
 500  * There cannot be any access by the offline cpu and therefore
 501  * synchronization is simplified.
 502  */
 503 void cpu_vm_stats_fold(int cpu)
 504 {
 505         struct zone *zone;
 506         int i;
 507         int global_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
 508
 509         for_each_populated_zone(zone) {
 510                 struct per_cpu_pageset *p;
 511
 512                 p = per_cpu_ptr(zone->pageset, cpu);
 513
 514                 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 515                         if (p->vm_stat_diff[i]) {
 516                                 int v;
 517
 518                                 v = p->vm_stat_diff[i];
 519                                 p->vm_stat_diff[i] = 0;
 520                                 atomic_long_add(v, &zone->vm_stat[i]);
 521                                 global_diff[i] += v;
 522                         }
 523         }
 524
 525         fold_diff(global_diff);
 526 }
 527
 528 /*
 529  * this is only called if !populated_zone(zone), which implies no other users of
 530  * pset->vm_stat_diff[] exsist.
 531  */
 532 void drain_zonestat(struct zone *zone, struct per_cpu_pageset *pset)
 533 {
 534         int i;
 535
 536         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 537                 if (pset->vm_stat_diff[i]) {
 538                         int v = pset->vm_stat_diff[i];
 539                         pset->vm_stat_diff[i] = 0;
 540                         atomic_long_add(v, &zone->vm_stat[i]);
 541                         atomic_long_add(v, &vm_stat[i]);
 542                 }
 543 }
 544 #endif
 545
 546 #ifdef CONFIG_NUMA
 547 /*
 548  * zonelist = the list of zones passed to the allocator
 549  * z        = the zone from which the allocation occurred.
 550  *
 551  * Must be called with interrupts disabled.
 552  *
 553  * When __GFP_OTHER_NODE is set assume the node of the preferred
 554  * zone is the local node. This is useful for daemons who allocate
 555  * memory on behalf of other processes.
 556  */
 557 void zone_statistics(struct zone *preferred_zone, struct zone *z, gfp_t flags)
 558 {
 559         if (z->zone_pgdat == preferred_zone->zone_pgdat) {
 560                 __inc_zone_state(z, NUMA_HIT);
 561         } else {
 562                 __inc_zone_state(z, NUMA_MISS);
 563                 __inc_zone_state(preferred_zone, NUMA_FOREIGN);
 564         }
 565         if (z->node == ((flags & __GFP_OTHER_NODE) ?
 566                         preferred_zone->node : numa_node_id()))
 567                 __inc_zone_state(z, NUMA_LOCAL);
 568         else
 569                 __inc_zone_state(z, NUMA_OTHER);
 570 }
 571 #endif
 572
 573 #ifdef CONFIG_COMPACTION
 574
 575 struct contig_page_info {
 576         unsigned long free_pages;
 577         unsigned long free_blocks_total;
 578         unsigned long free_blocks_suitable;
 579 };
 580
 581 /*
 582  * Calculate the number of free pages in a zone, how many contiguous
 583  * pages are free and how many are large enough to satisfy an allocation of
 584  * the target size. Note that this function makes no attempt to estimate
 585  * how many suitable free blocks there *might* be if MOVABLE pages were
 586  * migrated. Calculating that is possible, but expensive and can be
 587  * figured out from userspace
 588  */
 589 static void fill_contig_page_info(struct zone *zone,
 590                                 unsigned int suitable_order,
 591                                 struct contig_page_info *info)
 592 {
 593         unsigned int order;
 594
 595         info->free_pages = 0;
 596         info->free_blocks_total = 0;
 597         info->free_blocks_suitable = 0;
 598
 599         for (order = 0; order < MAX_ORDER; order++) {
 600                 unsigned long blocks;
 601
 602                 /* Count number of free blocks */
 603                 blocks = zone->free_area[order].nr_free;
 604                 info->free_blocks_total += blocks;
 605
 606                 /* Count free base pages */
 607                 info->free_pages += blocks << order;
 608
 609                 /* Count the suitable free blocks */
 610                 if (order >= suitable_order)
 611                         info->free_blocks_suitable += blocks <<
 612                                                 (order - suitable_order);
 613         }
 614 }
 615
 616 /*
 617  * A fragmentation index only makes sense if an allocation of a requested
 618  * size would fail. If that is true, the fragmentation index indicates
 619  * whether external fragmentation or a lack of memory was the problem.
 620  * The value can be used to determine if page reclaim or compaction
 621  * should be used
 622  */
 623 static int __fragmentation_index(unsigned int order, struct contig_page_info *info)
 624 {
 625         unsigned long requested = 1UL << order;
 626
 627         if (!info->free_blocks_total)
 628                 return 0;
 629
 630         /* Fragmentation index only makes sense when a request would fail */
 631         if (info->free_blocks_suitable)
 632                 return -1000;
 633
 634         /*
 635          * Index is between 0 and 1 so return within 3 decimal places
 636          *
 637          * 0 => allocation would fail due to lack of memory
 638          * 1 => allocation would fail due to fragmentation
 639          */
 640         return 1000 - div_u64( (1000+(div_u64(info->free_pages * 1000ULL, requested))), info->free_blocks_total);
 641 }
 642
 643 /* Same as __fragmentation index but allocs contig_page_info on stack */
 644 int fragmentation_index(struct zone *zone, unsigned int order)
 645 {
 646         struct contig_page_info info;
 647
 648         fill_contig_page_info(zone, order, &info);
 649         return __fragmentation_index(order, &info);
 650 }
 651 #endif
 652
 653 #if defined(CONFIG_PROC_FS) || defined(CONFIG_COMPACTION)
 654 #include <linux/proc_fs.h>
 655 #include <linux/seq_file.h>
 656
 657 static char * const migratetype_names[MIGRATE_TYPES] = {
 658         "Unmovable",
 659         "Reclaimable",
 660         "Movable",
 661         "Reserve",
 662 #ifdef CONFIG_CMA
 663         "CMA",
 664 #endif
 665 #ifdef CONFIG_MEMORY_ISOLATION
 666         "Isolate",
 667 #endif
 668 };
 669
 670 static void *frag_start(struct seq_file *m, loff_t *pos)
 671 {
 672         pg_data_t *pgdat;
 673         loff_t node = *pos;
 674         for (pgdat = first_online_pgdat();
 675              pgdat && node;
 676              pgdat = next_online_pgdat(pgdat))
 677                 --node;
 678
 679         return pgdat;
 680 }
 681
 682 static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
 683 {
 684         pg_data_t *pgdat = (pg_data_t *)arg;
 685
 686         (*pos)++;
 687         return next_online_pgdat(pgdat);
 688 }
 689
 690 static void frag_stop(struct seq_file *m, void *arg)
 691 {
 692 }
 693
 694 /* Walk all the zones in a node and print using a callback */
 695 static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat,
 696                 void (*print)(struct seq_file *m, pg_data_t *, struct zone *))
 697 {
 698         struct zone *zone;
 699         struct zone *node_zones = pgdat->node_zones;
 700         unsigned long flags;
 701
 702         for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
 703                 if (!populated_zone(zone))
 704                         continue;
 705
 706                 spin_lock_irqsave(&zone->lock, flags);
 707                 print(m, pgdat, zone);
 708                 spin_unlock_irqrestore(&zone->lock, flags);
 709         }
 710 }
 711 #endif
 712
 713 #if defined(CONFIG_PROC_FS) || defined(CONFIG_SYSFS) || defined(CONFIG_NUMA)
 714 #ifdef CONFIG_ZONE_DMA
 715 #define TEXT_FOR_DMA(xx) xx "_dma",
 716 #else
 717 #define TEXT_FOR_DMA(xx)
 718 #endif
 719
 720 #ifdef CONFIG_ZONE_DMA32
 721 #define TEXT_FOR_DMA32(xx) xx "_dma32",
 722 #else
 723 #define TEXT_FOR_DMA32(xx)
 724 #endif
 725
 726 #ifdef CONFIG_HIGHMEM
 727 #define TEXT_FOR_HIGHMEM(xx) xx "_high",
 728 #else
 729 #define TEXT_FOR_HIGHMEM(xx)
 730 #endif
 731
 732 #define TEXTS_FOR_ZONES(xx) TEXT_FOR_DMA(xx) TEXT_FOR_DMA32(xx) xx "_normal", \
 733                                         TEXT_FOR_HIGHMEM(xx) xx "_movable",
 734
 735 const char * const vmstat_text[] = {
 736         /* Zoned VM counters */
 737         "nr_free_pages",
 738         "nr_alloc_batch",
 739         "nr_inactive_anon",
 740         "nr_active_anon",
 741         "nr_inactive_file",
 742         "nr_active_file",
 743         "nr_unevictable",
 744         "nr_mlock",
 745         "nr_anon_pages",
 746         "nr_mapped",
 747         "nr_file_pages",
 748         "nr_dirty",
 749         "nr_writeback",
 750         "nr_slab_reclaimable",
 751         "nr_slab_unreclaimable",
 752         "nr_page_table_pages",
 753         "nr_kernel_stack",
 754         "nr_unstable",
 755         "nr_bounce",
 756         "nr_vmscan_write",
 757         "nr_vmscan_immediate_reclaim",
 758         "nr_writeback_temp",
 759         "nr_isolated_anon",
 760         "nr_isolated_file",
 761         "nr_shmem",
 762         "nr_dirtied",
 763         "nr_written",
 764
 765 #ifdef CONFIG_NUMA
 766         "numa_hit",
 767         "numa_miss",
 768         "numa_foreign",
 769         "numa_interleave",
 770         "numa_local",
 771         "numa_other",
 772 #endif
 773         "nr_anon_transparent_hugepages",
 774         "nr_free_cma",
 775         "nr_dirty_threshold",
 776         "nr_dirty_background_threshold",
 777
 778 #ifdef CONFIG_VM_EVENT_COUNTERS
 779         "pgpgin",
 780         "pgpgout",
 781         "pswpin",
 782         "pswpout",
 783
 784         TEXTS_FOR_ZONES("pgalloc")
 785
 786         "pgfree",
 787         "pgactivate",
 788         "pgdeactivate",
 789
 790         "pgfault",
 791         "pgmajfault",
 792
 793         TEXTS_FOR_ZONES("pgrefill")
 794         TEXTS_FOR_ZONES("pgsteal_kswapd")
 795         TEXTS_FOR_ZONES("pgsteal_direct")
 796         TEXTS_FOR_ZONES("pgscan_kswapd")
 797         TEXTS_FOR_ZONES("pgscan_direct")
 798         "pgscan_direct_throttle",
 799
 800 #ifdef CONFIG_NUMA
 801         "zone_reclaim_failed",
 802 #endif
 803         "pginodesteal",
 804         "slabs_scanned",
 805         "kswapd_inodesteal",
 806         "kswapd_low_wmark_hit_quickly",
 807         "kswapd_high_wmark_hit_quickly",
 808         "pageoutrun",
 809         "allocstall",
 810
 811         "pgrotated",
 812
 813 #ifdef CONFIG_NUMA_BALANCING
 814         "numa_pte_updates",
 815         "numa_huge_pte_updates",
 816         "numa_hint_faults",
 817         "numa_hint_faults_local",
 818         "numa_pages_migrated",
 819 #endif
 820 #ifdef CONFIG_MIGRATION
 821         "pgmigrate_success",
 822         "pgmigrate_fail",
 823 #endif
 824 #ifdef CONFIG_COMPACTION
 825         "compact_migrate_scanned",
 826         "compact_free_scanned",
 827         "compact_isolated",
 828         "compact_stall",
 829         "compact_fail",
 830         "compact_success",
 831 #endif
 832
 833 #ifdef CONFIG_HUGETLB_PAGE
 834         "htlb_buddy_alloc_success",
 835         "htlb_buddy_alloc_fail",
 836 #endif
 837         "unevictable_pgs_culled",
 838         "unevictable_pgs_scanned",
 839         "unevictable_pgs_rescued",
 840         "unevictable_pgs_mlocked",
 841         "unevictable_pgs_munlocked",
 842         "unevictable_pgs_cleared",
 843         "unevictable_pgs_stranded",
 844
 845 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 846         "thp_fault_alloc",
 847         "thp_fault_fallback",
 848         "thp_collapse_alloc",
 849         "thp_collapse_alloc_failed",
 850         "thp_split",
 851         "thp_zero_page_alloc",
 852         "thp_zero_page_alloc_failed",
 853 #endif
 854 #ifdef CONFIG_DEBUG_TLBFLUSH
 855 #ifdef CONFIG_SMP
 856         "nr_tlb_remote_flush",
 857         "nr_tlb_remote_flush_received",
 858 #endif /* CONFIG_SMP */
 859         "nr_tlb_local_flush_all",
 860         "nr_tlb_local_flush_one",
 861 #endif /* CONFIG_DEBUG_TLBFLUSH */
 862
 863 #endif /* CONFIG_VM_EVENTS_COUNTERS */
 864 };
 865 #endif /* CONFIG_PROC_FS || CONFIG_SYSFS || CONFIG_NUMA */
 866
 867
 868 #ifdef CONFIG_PROC_FS
 869 static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,
 870                                                 struct zone *zone)
 871 {
 872         int order;
 873
 874         seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
 875         for (order = 0; order < MAX_ORDER; ++order)
 876                 seq_printf(m, "%6lu ", zone->free_area[order].nr_free);
 877         seq_putc(m, '\n');
 878 }
 879
 880 /*
 881  * This walks the free areas for each zone.
 882  */
 883 static int frag_show(struct seq_file *m, void *arg)
 884 {
 885         pg_data_t *pgdat = (pg_data_t *)arg;
 886         walk_zones_in_node(m, pgdat, frag_show_print);
 887         return 0;
 888 }
 889
 890 static void pagetypeinfo_showfree_print(struct seq_file *m,
 891                                         pg_data_t *pgdat, struct zone *zone)
 892 {
 893         int order, mtype;
 894
 895         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++) {
 896                 seq_printf(m, "Node %4d, zone %8s, type %12s ",
 897                                         pgdat->node_id,
 898                                         zone->name,
 899                                         migratetype_names[mtype]);
 900                 for (order = 0; order < MAX_ORDER; ++order) {
 901                         unsigned long freecount = 0;
 902                         struct free_area *area;
 903                         struct list_head *curr;
 904
 905                         area = &(zone->free_area[order]);
 906
 907                         list_for_each(curr, &area->free_list[mtype])
 908                                 freecount++;
 909                         seq_printf(m, "%6lu ", freecount);
 910                 }
 911                 seq_putc(m, '\n');
 912         }
 913 }
 914
 915 /* Print out the free pages at each order for each migatetype */
 916 static int pagetypeinfo_showfree(struct seq_file *m, void *arg)
 917 {
 918         int order;
 919         pg_data_t *pgdat = (pg_data_t *)arg;
 920
 921         /* Print header */
 922         seq_printf(m, "%-43s ", "Free pages count per migrate type at order");
 923         for (order = 0; order < MAX_ORDER; ++order)
 924                 seq_printf(m, "%6d ", order);
 925         seq_putc(m, '\n');
 926
 927         walk_zones_in_node(m, pgdat, pagetypeinfo_showfree_print);
 928
 929         return 0;
 930 }
 931
 932 static void pagetypeinfo_showblockcount_print(struct seq_file *m,
 933                                         pg_data_t *pgdat, struct zone *zone)
 934 {
 935         int mtype;
 936         unsigned long pfn;
 937         unsigned long start_pfn = zone->zone_start_pfn;
 938         unsigned long end_pfn = zone_end_pfn(zone);
 939         unsigned long count[MIGRATE_TYPES] = { 0, };
 940
 941         for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
 942                 struct page *page;
 943
 944                 if (!pfn_valid(pfn))
 945                         continue;
 946
 947                 page = pfn_to_page(pfn);
 948
 949                 /* Watch for unexpected holes punched in the memmap */
 950                 if (!memmap_valid_within(pfn, page, zone))
 951                         continue;
 952
 953                 mtype = get_pageblock_migratetype(page);
 954
 955                 if (mtype < MIGRATE_TYPES)
 956                         count[mtype]++;
 957         }
 958
 959         /* Print counts */
 960         seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
 961         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
 962                 seq_printf(m, "%12lu ", count[mtype]);
 963         seq_putc(m, '\n');
 964 }
 965
 966 /* Print out the free pages at each order for each migratetype */
 967 static int pagetypeinfo_showblockcount(struct seq_file *m, void *arg)
 968 {
 969         int mtype;
 970         pg_data_t *pgdat = (pg_data_t *)arg;
 971
 972         seq_printf(m, "\n%-23s", "Number of blocks type ");
 973         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
 974                 seq_printf(m, "%12s ", migratetype_names[mtype]);
 975         seq_putc(m, '\n');
 976         walk_zones_in_node(m, pgdat, pagetypeinfo_showblockcount_print);
 977
 978         return 0;
 979 }
 980
 981 /*
 982  * This prints out statistics in relation to grouping pages by mobility.
 983  * It is expensive to collect so do not constantly read the file.
 984  */
 985 static int pagetypeinfo_show(struct seq_file *m, void *arg)
 986 {
 987         pg_data_t *pgdat = (pg_data_t *)arg;
 988
 989         /* check memoryless node */
 990         if (!node_state(pgdat->node_id, N_MEMORY))
 991                 return 0;
 992
 993         seq_printf(m, "Page block order: %d\n", pageblock_order);
 994         seq_printf(m, "Pages per block:  %lu\n", pageblock_nr_pages);
 995         seq_putc(m, '\n');
 996         pagetypeinfo_showfree(m, pgdat);
 997         pagetypeinfo_showblockcount(m, pgdat);
 998
 999         return 0;
1000 }
1001
1002 static const struct seq_operations fragmentation_op = {
1003         .start  = frag_start,
1004         .next   = frag_next,
1005         .stop   = frag_stop,
1006         .show   = frag_show,
1007 };
1008
1009 static int fragmentation_open(struct inode *inode, struct file *file)
1010 {
1011         return seq_open(file, &fragmentation_op);
1012 }
1013
1014 static const struct file_operations fragmentation_file_operations = {
1015         .open           = fragmentation_open,
1016         .read           = seq_read,
1017         .llseek         = seq_lseek,
1018         .release        = seq_release,
1019 };
1020
1021 static const struct seq_operations pagetypeinfo_op = {
1022         .start  = frag_start,
1023         .next   = frag_next,
1024         .stop   = frag_stop,
1025         .show   = pagetypeinfo_show,
1026 };
1027
1028 static int pagetypeinfo_open(struct inode *inode, struct file *file)
1029 {
1030         return seq_open(file, &pagetypeinfo_op);
1031 }
1032
1033 static const struct file_operations pagetypeinfo_file_ops = {
1034         .open           = pagetypeinfo_open,
1035         .read           = seq_read,
1036         .llseek         = seq_lseek,
1037         .release        = seq_release,
1038 };
1039
1040 static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
1041                                                         struct zone *zone)
1042 {
1043         int i;
1044         seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name);
1045         seq_printf(m,
1046                    "\n  pages free     %lu"
1047                    "\n        min      %lu"
1048                    "\n        low      %lu"
1049                    "\n        high     %lu"
1050                    "\n        scanned  %lu"
1051                    "\n        spanned  %lu"
1052                    "\n        present  %lu"
1053                    "\n        managed  %lu",
1054                    zone_page_state(zone, NR_FREE_PAGES),
1055                    min_wmark_pages(zone),
1056                    low_wmark_pages(zone),
1057                    high_wmark_pages(zone),
1058                    zone->pages_scanned,
1059                    zone->spanned_pages,
1060                    zone->present_pages,
1061                    zone->managed_pages);
1062
1063         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
1064                 seq_printf(m, "\n    %-12s %lu", vmstat_text[i],
1065                                 zone_page_state(zone, i));
1066
1067         seq_printf(m,
1068                    "\n        protection: (%lu",
1069                    zone->lowmem_reserve[0]);
1070         for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++)
1071                 seq_printf(m, ", %lu", zone->lowmem_reserve[i]);
1072         seq_printf(m,
1073                    ")"
1074                    "\n  pagesets");
1075         for_each_online_cpu(i) {
1076                 struct per_cpu_pageset *pageset;
1077
1078                 pageset = per_cpu_ptr(zone->pageset, i);
1079                 seq_printf(m,
1080                            "\n    cpu: %i"
1081                            "\n              count: %i"
1082                            "\n              high:  %i"
1083                            "\n              batch: %i",
1084                            i,
1085                            pageset->pcp.count,
1086                            pageset->pcp.high,
1087                            pageset->pcp.batch);
1088 #ifdef CONFIG_SMP
1089                 seq_printf(m, "\n  vm stats threshold: %d",
1090                                 pageset->stat_threshold);
1091 #endif
1092         }
1093         seq_printf(m,
1094                    "\n  all_unreclaimable: %u"
1095                    "\n  start_pfn:         %lu"
1096                    "\n  inactive_ratio:    %u",
1097                    !zone_reclaimable(zone),
1098                    zone->zone_start_pfn,
1099                    zone->inactive_ratio);
1100         seq_putc(m, '\n');
1101 }
1102
1103 /*
1104  * Output information about zones in @pgdat.
1105  */
1106 static int zoneinfo_show(struct seq_file *m, void *arg)
1107 {
1108         pg_data_t *pgdat = (pg_data_t *)arg;
1109         walk_zones_in_node(m, pgdat, zoneinfo_show_print);
1110         return 0;
1111 }
1112
1113 static const struct seq_operations zoneinfo_op = {
1114         .start  = frag_start, /* iterate over all zones. The same as in
1115                                * fragmentation. */
1116         .next   = frag_next,
1117         .stop   = frag_stop,
1118         .show   = zoneinfo_show,
1119 };
1120
1121 static int zoneinfo_open(struct inode *inode, struct file *file)
1122 {
1123         return seq_open(file, &zoneinfo_op);
1124 }
1125
1126 static const struct file_operations proc_zoneinfo_file_operations = {
1127         .open           = zoneinfo_open,
1128         .read           = seq_read,
1129         .llseek         = seq_lseek,
1130         .release        = seq_release,
1131 };
1132
1133 enum writeback_stat_item {
1134         NR_DIRTY_THRESHOLD,
1135         NR_DIRTY_BG_THRESHOLD,
1136         NR_VM_WRITEBACK_STAT_ITEMS,
1137 };
1138
1139 static void *vmstat_start(struct seq_file *m, loff_t *pos)
1140 {
1141         unsigned long *v;
1142         int i, stat_items_size;
1143
1144         if (*pos >= ARRAY_SIZE(vmstat_text))
1145                 return NULL;
1146         stat_items_size = NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long) +
1147                           NR_VM_WRITEBACK_STAT_ITEMS * sizeof(unsigned long);
1148
1149 #ifdef CONFIG_VM_EVENT_COUNTERS
1150         stat_items_size += sizeof(struct vm_event_state);
1151 #endif
1152
1153         v = kmalloc(stat_items_size, GFP_KERNEL);
1154         m->private = v;
1155         if (!v)
1156                 return ERR_PTR(-ENOMEM);
1157         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
1158                 v[i] = global_page_state(i);
1159         v += NR_VM_ZONE_STAT_ITEMS;
1160
1161         global_dirty_limits(v + NR_DIRTY_BG_THRESHOLD,
1162                             v + NR_DIRTY_THRESHOLD);
1163         v += NR_VM_WRITEBACK_STAT_ITEMS;
1164
1165 #ifdef CONFIG_VM_EVENT_COUNTERS
1166         all_vm_events(v);
1167         v[PGPGIN] /= 2;         /* sectors -> kbytes */
1168         v[PGPGOUT] /= 2;
1169 #endif
1170         return (unsigned long *)m->private + *pos;
1171 }
1172
1173 static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)
1174 {
1175         (*pos)++;
1176         if (*pos >= ARRAY_SIZE(vmstat_text))
1177                 return NULL;
1178         return (unsigned long *)m->private + *pos;
1179 }
1180
1181 static int vmstat_show(struct seq_file *m, void *arg)
1182 {
1183         unsigned long *l = arg;
1184         unsigned long off = l - (unsigned long *)m->private;
1185
1186         seq_printf(m, "%s %lu\n", vmstat_text[off], *l);
1187         return 0;
1188 }
1189
1190 static void vmstat_stop(struct seq_file *m, void *arg)
1191 {
1192         kfree(m->private);
1193         m->private = NULL;
1194 }
1195
1196 static const struct seq_operations vmstat_op = {
1197         .start  = vmstat_start,
1198         .next   = vmstat_next,
1199         .stop   = vmstat_stop,
1200         .show   = vmstat_show,
1201 };
1202
1203 static int vmstat_open(struct inode *inode, struct file *file)
1204 {
1205         return seq_open(file, &vmstat_op);
1206 }
1207
1208 static const struct file_operations proc_vmstat_file_operations = {
1209         .open           = vmstat_open,
1210         .read           = seq_read,
1211         .llseek         = seq_lseek,
1212         .release        = seq_release,
1213 };
1214 #endif /* CONFIG_PROC_FS */
1215
1216 #ifdef CONFIG_SMP
1217 static DEFINE_PER_CPU(struct delayed_work, vmstat_work);
1218 int sysctl_stat_interval __read_mostly = HZ;
1219
1220 static void vmstat_update(struct work_struct *w)
1221 {
1222         refresh_cpu_vm_stats();
1223         schedule_delayed_work(&__get_cpu_var(vmstat_work),
1224                 round_jiffies_relative(sysctl_stat_interval));
1225 }
1226
1227 static void start_cpu_timer(int cpu)
1228 {
1229         struct delayed_work *work = &per_cpu(vmstat_work, cpu);
1230
1231         INIT_DEFERRABLE_WORK(work, vmstat_update);
1232         schedule_delayed_work_on(cpu, work, __round_jiffies_relative(HZ, cpu));
1233 }
1234
1235 static void vmstat_cpu_dead(int node)
1236 {
1237         int cpu;
1238
1239         get_online_cpus();
1240         for_each_online_cpu(cpu)
1241                 if (cpu_to_node(cpu) == node)
1242                         goto end;
1243
1244         node_clear_state(node, N_CPU);
1245 end:
1246         put_online_cpus();
1247 }
1248
1249 /*
1250  * Use the cpu notifier to insure that the thresholds are recalculated
1251  * when necessary.
1252  */
1253 static int vmstat_cpuup_callback(struct notifier_block *nfb,
1254                 unsigned long action,
1255                 void *hcpu)
1256 {
1257         long cpu = (long)hcpu;
1258
1259         switch (action) {
1260         case CPU_ONLINE:
1261         case CPU_ONLINE_FROZEN:
1262                 refresh_zone_stat_thresholds();
1263                 start_cpu_timer(cpu);
1264                 node_set_state(cpu_to_node(cpu), N_CPU);
1265                 break;
1266         case CPU_DOWN_PREPARE:
1267         case CPU_DOWN_PREPARE_FROZEN:
1268                 cancel_delayed_work_sync(&per_cpu(vmstat_work, cpu));
1269                 per_cpu(vmstat_work, cpu).work.func = NULL;
1270                 break;
1271         case CPU_DOWN_FAILED:
1272         case CPU_DOWN_FAILED_FROZEN:
1273                 start_cpu_timer(cpu);
1274                 break;
1275         case CPU_DEAD:
1276         case CPU_DEAD_FROZEN:
1277                 refresh_zone_stat_thresholds();
1278                 vmstat_cpu_dead(cpu_to_node(cpu));
1279                 break;
1280         default:
1281                 break;
1282         }
1283         return NOTIFY_OK;
1284 }
1285
1286 static struct notifier_block vmstat_notifier =
1287         { &vmstat_cpuup_callback, NULL, 0 };
1288 #endif
1289
1290 static int __init setup_vmstat(void)
1291 {
1292 #ifdef CONFIG_SMP
1293         int cpu;
1294
1295         register_cpu_notifier(&vmstat_notifier);
1296
1297         get_online_cpus();
1298         for_each_online_cpu(cpu) {
1299                 start_cpu_timer(cpu);
1300                 node_set_state(cpu_to_node(cpu), N_CPU);
1301         }
1302         put_online_cpus();
1303 #endif
1304 #ifdef CONFIG_PROC_FS
1305         proc_create("buddyinfo", S_IRUGO, NULL, &fragmentation_file_operations);
1306         proc_create("pagetypeinfo", S_IRUGO, NULL, &pagetypeinfo_file_ops);
1307         proc_create("vmstat", S_IRUGO, NULL, &proc_vmstat_file_operations);
1308         proc_create("zoneinfo", S_IRUGO, NULL, &proc_zoneinfo_file_operations);
1309 #endif
1310         return 0;
1311 }
1312 module_init(setup_vmstat)
1313
1314 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)
1315 #include <linux/debugfs.h>
1316
1317
1318 /*
1319  * Return an index indicating how much of the available free memory is
1320  * unusable for an allocation of the requested size.
1321  */
1322 static int unusable_free_index(unsigned int order,
1323                                 struct contig_page_info *info)
1324 {
1325         /* No free memory is interpreted as all free memory is unusable */
1326         if (info->free_pages == 0)
1327                 return 1000;
1328
1329         /*
1330          * Index should be a value between 0 and 1. Return a value to 3
1331          * decimal places.
1332          *
1333          * 0 => no fragmentation
1334          * 1 => high fragmentation
1335          */
1336         return div_u64((info->free_pages - (info->free_blocks_suitable << order)) * 1000ULL, info->free_pages);
1337
1338 }
1339
1340 static void unusable_show_print(struct seq_file *m,
1341                                         pg_data_t *pgdat, struct zone *zone)
1342 {
1343         unsigned int order;
1344         int index;
1345         struct contig_page_info info;
1346
1347         seq_printf(m, "Node %d, zone %8s ",
1348                                 pgdat->node_id,
1349                                 zone->name);
1350         for (order = 0; order < MAX_ORDER; ++order) {
1351                 fill_contig_page_info(zone, order, &info);
1352                 index = unusable_free_index(order, &info);
1353                 seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
1354         }
1355
1356         seq_putc(m, '\n');
1357 }
1358
1359 /*
1360  * Display unusable free space index
1361  *
1362  * The unusable free space index measures how much of the available free
1363  * memory cannot be used to satisfy an allocation of a given size and is a
1364  * value between 0 and 1. The higher the value, the more of free memory is
1365  * unusable and by implication, the worse the external fragmentation is. This
1366  * can be expressed as a percentage by multiplying by 100.
1367  */
1368 static int unusable_show(struct seq_file *m, void *arg)
1369 {
1370         pg_data_t *pgdat = (pg_data_t *)arg;
1371
1372         /* check memoryless node */
1373         if (!node_state(pgdat->node_id, N_MEMORY))
1374                 return 0;
1375
1376         walk_zones_in_node(m, pgdat, unusable_show_print);
1377
1378         return 0;
1379 }
1380
1381 static const struct seq_operations unusable_op = {
1382         .start  = frag_start,
1383         .next   = frag_next,
1384         .stop   = frag_stop,
1385         .show   = unusable_show,
1386 };
1387
1388 static int unusable_open(struct inode *inode, struct file *file)
1389 {
1390         return seq_open(file, &unusable_op);
1391 }
1392
1393 static const struct file_operations unusable_file_ops = {
1394         .open           = unusable_open,
1395         .read           = seq_read,
1396         .llseek         = seq_lseek,
1397         .release        = seq_release,
1398 };
1399
1400 static void extfrag_show_print(struct seq_file *m,
1401                                         pg_data_t *pgdat, struct zone *zone)
1402 {
1403         unsigned int order;
1404         int index;
1405
1406         /* Alloc on stack as interrupts are disabled for zone walk */
1407         struct contig_page_info info;
1408
1409         seq_printf(m, "Node %d, zone %8s ",
1410                                 pgdat->node_id,
1411                                 zone->name);
1412         for (order = 0; order < MAX_ORDER; ++order) {
1413                 fill_contig_page_info(zone, order, &info);
1414                 index = __fragmentation_index(order, &info);
1415                 seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
1416         }
1417
1418         seq_putc(m, '\n');
1419 }
1420
1421 /*
1422  * Display fragmentation index for orders that allocations would fail for
1423  */
1424 static int extfrag_show(struct seq_file *m, void *arg)
1425 {
1426         pg_data_t *pgdat = (pg_data_t *)arg;
1427
1428         walk_zones_in_node(m, pgdat, extfrag_show_print);
1429
1430         return 0;
1431 }
1432
1433 static const struct seq_operations extfrag_op = {
1434         .start  = frag_start,
1435         .next   = frag_next,
1436         .stop   = frag_stop,
1437         .show   = extfrag_show,
1438 };
1439
1440 static int extfrag_open(struct inode *inode, struct file *file)
1441 {
1442         return seq_open(file, &extfrag_op);
1443 }
1444
1445 static const struct file_operations extfrag_file_ops = {
1446         .open           = extfrag_open,
1447         .read           = seq_read,
1448         .llseek         = seq_lseek,
1449         .release        = seq_release,
1450 };
1451
1452 static int __init extfrag_debug_init(void)
1453 {
1454         struct dentry *extfrag_debug_root;
1455
1456         extfrag_debug_root = debugfs_create_dir("extfrag", NULL);
1457         if (!extfrag_debug_root)
1458                 return -ENOMEM;
1459
1460         if (!debugfs_create_file("unusable_index", 0444,
1461                         extfrag_debug_root, NULL, &unusable_file_ops))
1462                 goto fail;
1463
1464         if (!debugfs_create_file("extfrag_index", 0444,
1465                         extfrag_debug_root, NULL, &extfrag_file_ops))
1466                 goto fail;
1467
1468         return 0;
1469 fail:
1470         debugfs_remove_recursive(extfrag_debug_root);
1471         return -ENOMEM;
1472 }
1473
1474 module_init(extfrag_debug_init);
1475 #endif