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/cpumask.h>
  18 #include <linux/vmstat.h>
  19 #include <linux/sched.h>
  20 #include <linux/math64.h>
  21 #include <linux/writeback.h>
  22 #include <linux/compaction.h>
  23
  24 #ifdef CONFIG_VM_EVENT_COUNTERS
  25 DEFINE_PER_CPU(struct vm_event_state, vm_event_states) = {{0}};
  26 EXPORT_PER_CPU_SYMBOL(vm_event_states);
  27
  28 static void sum_vm_events(unsigned long *ret)
  29 {
  30         int cpu;
  31         int i;
  32
  33         memset(ret, 0, NR_VM_EVENT_ITEMS * sizeof(unsigned long));
  34
  35         for_each_online_cpu(cpu) {
  36                 struct vm_event_state *this = &per_cpu(vm_event_states, cpu);
  37
  38                 for (i = 0; i < NR_VM_EVENT_ITEMS; i++)
  39                         ret[i] += this->event[i];
  40         }
  41 }
  42
  43 /*
  44  * Accumulate the vm event counters across all CPUs.
  45  * The result is unavoidably approximate - it can change
  46  * during and after execution of this function.
  47 */
  48 void all_vm_events(unsigned long *ret)
  49 {
  50         get_online_cpus();
  51         sum_vm_events(ret);
  52         put_online_cpus();
  53 }
  54 EXPORT_SYMBOL_GPL(all_vm_events);
  55
  56 /*
  57  * Fold the foreign cpu events into our own.
  58  *
  59  * This is adding to the events on one processor
  60  * but keeps the global counts constant.
  61  */
  62 void vm_events_fold_cpu(int cpu)
  63 {
  64         struct vm_event_state *fold_state = &per_cpu(vm_event_states, cpu);
  65         int i;
  66
  67         for (i = 0; i < NR_VM_EVENT_ITEMS; i++) {
  68                 count_vm_events(i, fold_state->event[i]);
  69                 fold_state->event[i] = 0;
  70         }
  71 }
  72
  73 #endif /* CONFIG_VM_EVENT_COUNTERS */
  74
  75 /*
  76  * Manage combined zone based / global counters
  77  *
  78  * vm_stat contains the global counters
  79  */
  80 atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS] __cacheline_aligned_in_smp;
  81 EXPORT_SYMBOL(vm_stat);
  82
  83 #ifdef CONFIG_SMP
  84
  85 int calculate_pressure_threshold(struct zone *zone)
  86 {
  87         int threshold;
  88         int watermark_distance;
  89
  90         /*
  91          * As vmstats are not up to date, there is drift between the estimated
  92          * and real values. For high thresholds and a high number of CPUs, it
  93          * is possible for the min watermark to be breached while the estimated
  94          * value looks fine. The pressure threshold is a reduced value such
  95          * that even the maximum amount of drift will not accidentally breach
  96          * the min watermark
  97          */
  98         watermark_distance = low_wmark_pages(zone) - min_wmark_pages(zone);
  99         threshold = max(1, (int)(watermark_distance / num_online_cpus()));
 100
 101         /*
 102          * Maximum threshold is 125
 103          */
 104         threshold = min(125, threshold);
 105
 106         return threshold;
 107 }
 108
 109 int calculate_normal_threshold(struct zone *zone)
 110 {
 111         int threshold;
 112         int mem;        /* memory in 128 MB units */
 113
 114         /*
 115          * The threshold scales with the number of processors and the amount
 116          * of memory per zone. More memory means that we can defer updates for
 117          * longer, more processors could lead to more contention.
 118          * fls() is used to have a cheap way of logarithmic scaling.
 119          *
 120          * Some sample thresholds:
 121          *
 122          * Threshold    Processors      (fls)   Zonesize        fls(mem+1)
 123          * ------------------------------------------------------------------
 124          * 8            1               1       0.9-1 GB        4
 125          * 16           2               2       0.9-1 GB        4
 126          * 20           2               2       1-2 GB          5
 127          * 24           2               2       2-4 GB          6
 128          * 28           2               2       4-8 GB          7
 129          * 32           2               2       8-16 GB         8
 130          * 4            2               2       <128M           1
 131          * 30           4               3       2-4 GB          5
 132          * 48           4               3       8-16 GB         8
 133          * 32           8               4       1-2 GB          4
 134          * 32           8               4       0.9-1GB         4
 135          * 10           16              5       <128M           1
 136          * 40           16              5       900M            4
 137          * 70           64              7       2-4 GB          5
 138          * 84           64              7       4-8 GB          6
 139          * 108          512             9       4-8 GB          6
 140          * 125          1024            10      8-16 GB         8
 141          * 125          1024            10      16-32 GB        9
 142          */
 143
 144         mem = zone->managed_pages >> (27 - PAGE_SHIFT);
 145
 146         threshold = 2 * fls(num_online_cpus()) * (1 + fls(mem));
 147
 148         /*
 149          * Maximum threshold is 125
 150          */
 151         threshold = min(125, threshold);
 152
 153         return threshold;
 154 }
 155
 156 /*
 157  * Refresh the thresholds for each zone.
 158  */
 159 void refresh_zone_stat_thresholds(void)
 160 {
 161         struct zone *zone;
 162         int cpu;
 163         int threshold;
 164
 165         for_each_populated_zone(zone) {
 166                 unsigned long max_drift, tolerate_drift;
 167
 168                 threshold = calculate_normal_threshold(zone);
 169
 170                 for_each_online_cpu(cpu)
 171                         per_cpu_ptr(zone->pageset, cpu)->stat_threshold
 172                                                         = threshold;
 173
 174                 /*
 175                  * Only set percpu_drift_mark if there is a danger that
 176                  * NR_FREE_PAGES reports the low watermark is ok when in fact
 177                  * the min watermark could be breached by an allocation
 178                  */
 179                 tolerate_drift = low_wmark_pages(zone) - min_wmark_pages(zone);
 180                 max_drift = num_online_cpus() * threshold;
 181                 if (max_drift > tolerate_drift)
 182                         zone->percpu_drift_mark = high_wmark_pages(zone) +
 183                                         max_drift;
 184         }
 185 }
 186
 187 void set_pgdat_percpu_threshold(pg_data_t *pgdat,
 188                                 int (*calculate_pressure)(struct zone *))
 189 {
 190         struct zone *zone;
 191         int cpu;
 192         int threshold;
 193         int i;
 194
 195         for (i = 0; i < pgdat->nr_zones; i++) {
 196                 zone = &pgdat->node_zones[i];
 197                 if (!zone->percpu_drift_mark)
 198                         continue;
 199
 200                 threshold = (*calculate_pressure)(zone);
 201                 for_each_possible_cpu(cpu)
 202                         per_cpu_ptr(zone->pageset, cpu)->stat_threshold
 203                                                         = threshold;
 204         }
 205 }
 206
 207 /*
 208  * For use when we know that interrupts are disabled.
 209  */
 210 void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 211                                 int delta)
 212 {
 213         struct per_cpu_pageset __percpu *pcp = zone->pageset;
 214         s8 __percpu *p = pcp->vm_stat_diff + item;
 215         long x;
 216         long t;
 217
 218         x = delta + __this_cpu_read(*p);
 219
 220         t = __this_cpu_read(pcp->stat_threshold);
 221
 222         if (unlikely(x > t || x < -t)) {
 223                 zone_page_state_add(x, zone, item);
 224                 x = 0;
 225         }
 226         __this_cpu_write(*p, x);
 227 }
 228 EXPORT_SYMBOL(__mod_zone_page_state);
 229
 230 /*
 231  * Optimized increment and decrement functions.
 232  *
 233  * These are only for a single page and therefore can take a struct page *
 234  * argument instead of struct zone *. This allows the inclusion of the code
 235  * generated for page_zone(page) into the optimized functions.
 236  *
 237  * No overflow check is necessary and therefore the differential can be
 238  * incremented or decremented in place which may allow the compilers to
 239  * generate better code.
 240  * The increment or decrement is known and therefore one boundary check can
 241  * be omitted.
 242  *
 243  * NOTE: These functions are very performance sensitive. Change only
 244  * with care.
 245  *
 246  * Some processors have inc/dec instructions that are atomic vs an interrupt.
 247  * However, the code must first determine the differential location in a zone
 248  * based on the processor number and then inc/dec the counter. There is no
 249  * guarantee without disabling preemption that the processor will not change
 250  * in between and therefore the atomicity vs. interrupt cannot be exploited
 251  * in a useful way here.
 252  */
 253 void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
 254 {
 255         struct per_cpu_pageset __percpu *pcp = zone->pageset;
 256         s8 __percpu *p = pcp->vm_stat_diff + item;
 257         s8 v, t;
 258
 259         v = __this_cpu_inc_return(*p);
 260         t = __this_cpu_read(pcp->stat_threshold);
 261         if (unlikely(v > t)) {
 262                 s8 overstep = t >> 1;
 263
 264                 zone_page_state_add(v + overstep, zone, item);
 265                 __this_cpu_write(*p, -overstep);
 266         }
 267 }
 268
 269 void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
 270 {
 271         __inc_zone_state(page_zone(page), item);
 272 }
 273 EXPORT_SYMBOL(__inc_zone_page_state);
 274
 275 void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
 276 {
 277         struct per_cpu_pageset __percpu *pcp = zone->pageset;
 278         s8 __percpu *p = pcp->vm_stat_diff + item;
 279         s8 v, t;
 280
 281         v = __this_cpu_dec_return(*p);
 282         t = __this_cpu_read(pcp->stat_threshold);
 283         if (unlikely(v < - t)) {
 284                 s8 overstep = t >> 1;
 285
 286                 zone_page_state_add(v - overstep, zone, item);
 287                 __this_cpu_write(*p, overstep);
 288         }
 289 }
 290
 291 void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
 292 {
 293         __dec_zone_state(page_zone(page), item);
 294 }
 295 EXPORT_SYMBOL(__dec_zone_page_state);
 296
 297 #ifdef CONFIG_HAVE_CMPXCHG_LOCAL
 298 /*
 299  * If we have cmpxchg_local support then we do not need to incur the overhead
 300  * that comes with local_irq_save/restore if we use this_cpu_cmpxchg.
 301  *
 302  * mod_state() modifies the zone counter state through atomic per cpu
 303  * operations.
 304  *
 305  * Overstep mode specifies how overstep should handled:
 306  *     0       No overstepping
 307  *     1       Overstepping half of threshold
 308  *     -1      Overstepping minus half of threshold
 309 */
 310 static inline void mod_state(struct zone *zone,
 311        enum zone_stat_item item, int delta, int overstep_mode)
 312 {
 313         struct per_cpu_pageset __percpu *pcp = zone->pageset;
 314         s8 __percpu *p = pcp->vm_stat_diff + item;
 315         long o, n, t, z;
 316
 317         do {
 318                 z = 0;  /* overflow to zone counters */
 319
 320                 /*
 321                  * The fetching of the stat_threshold is racy. We may apply
 322                  * a counter threshold to the wrong the cpu if we get
 323                  * rescheduled while executing here. However, the next
 324                  * counter update will apply the threshold again and
 325                  * therefore bring the counter under the threshold again.
 326                  *
 327                  * Most of the time the thresholds are the same anyways
 328                  * for all cpus in a zone.
 329                  */
 330                 t = this_cpu_read(pcp->stat_threshold);
 331
 332                 o = this_cpu_read(*p);
 333                 n = delta + o;
 334
 335                 if (n > t || n < -t) {
 336                         int os = overstep_mode * (t >> 1) ;
 337
 338                         /* Overflow must be added to zone counters */
 339                         z = n + os;
 340                         n = -os;
 341                 }
 342         } while (this_cpu_cmpxchg(*p, o, n) != o);
 343
 344         if (z)
 345                 zone_page_state_add(z, zone, item);
 346 }
 347
 348 void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 349                                         int delta)
 350 {
 351         mod_state(zone, item, delta, 0);
 352 }
 353 EXPORT_SYMBOL(mod_zone_page_state);
 354
 355 void inc_zone_state(struct zone *zone, enum zone_stat_item item)
 356 {
 357         mod_state(zone, item, 1, 1);
 358 }
 359
 360 void inc_zone_page_state(struct page *page, enum zone_stat_item item)
 361 {
 362         mod_state(page_zone(page), item, 1, 1);
 363 }
 364 EXPORT_SYMBOL(inc_zone_page_state);
 365
 366 void dec_zone_page_state(struct page *page, enum zone_stat_item item)
 367 {
 368         mod_state(page_zone(page), item, -1, -1);
 369 }
 370 EXPORT_SYMBOL(dec_zone_page_state);
 371 #else
 372 /*
 373  * Use interrupt disable to serialize counter updates
 374  */
 375 void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 376                                         int delta)
 377 {
 378         unsigned long flags;
 379
 380         local_irq_save(flags);
 381         __mod_zone_page_state(zone, item, delta);
 382         local_irq_restore(flags);
 383 }
 384 EXPORT_SYMBOL(mod_zone_page_state);
 385
 386 void inc_zone_state(struct zone *zone, enum zone_stat_item item)
 387 {
 388         unsigned long flags;
 389
 390         local_irq_save(flags);
 391         __inc_zone_state(zone, item);
 392         local_irq_restore(flags);
 393 }
 394
 395 void inc_zone_page_state(struct page *page, enum zone_stat_item item)
 396 {
 397         unsigned long flags;
 398         struct zone *zone;
 399
 400         zone = page_zone(page);
 401         local_irq_save(flags);
 402         __inc_zone_state(zone, item);
 403         local_irq_restore(flags);
 404 }
 405 EXPORT_SYMBOL(inc_zone_page_state);
 406
 407 void dec_zone_page_state(struct page *page, enum zone_stat_item item)
 408 {
 409         unsigned long flags;
 410
 411         local_irq_save(flags);
 412         __dec_zone_page_state(page, item);
 413         local_irq_restore(flags);
 414 }
 415 EXPORT_SYMBOL(dec_zone_page_state);
 416 #endif
 417
 418 /*
 419  * Update the zone counters for one cpu.
 420  *
 421  * The cpu specified must be either the current cpu or a processor that
 422  * is not online. If it is the current cpu then the execution thread must
 423  * be pinned to the current cpu.
 424  *
 425  * Note that refresh_cpu_vm_stats strives to only access
 426  * node local memory. The per cpu pagesets on remote zones are placed
 427  * in the memory local to the processor using that pageset. So the
 428  * loop over all zones will access a series of cachelines local to
 429  * the processor.
 430  *
 431  * The call to zone_page_state_add updates the cachelines with the
 432  * statistics in the remote zone struct as well as the global cachelines
 433  * with the global counters. These could cause remote node cache line
 434  * bouncing and will have to be only done when necessary.
 435  */
 436 bool refresh_cpu_vm_stats(int cpu)
 437 {
 438         struct zone *zone;
 439         int i;
 440         int global_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
 441         bool vm_activity = false;
 442
 443         for_each_populated_zone(zone) {
 444                 struct per_cpu_pageset *p;
 445
 446                 p = per_cpu_ptr(zone->pageset, cpu);
 447
 448                 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 449                         if (p->vm_stat_diff[i]) {
 450                                 unsigned long flags;
 451                                 int v;
 452
 453                                 local_irq_save(flags);
 454                                 v = p->vm_stat_diff[i];
 455                                 p->vm_stat_diff[i] = 0;
 456                                 local_irq_restore(flags);
 457                                 atomic_long_add(v, &zone->vm_stat[i]);
 458                                 global_diff[i] += v;
 459 #ifdef CONFIG_NUMA
 460                                 /* 3 seconds idle till flush */
 461                                 p->expire = 3;
 462 #endif
 463                         }
 464                 cond_resched();
 465 #ifdef CONFIG_NUMA
 466                 /*
 467                  * Deal with draining the remote pageset of this
 468                  * processor
 469                  *
 470                  * Check if there are pages remaining in this pageset
 471                  * if not then there is nothing to expire.
 472                  */
 473                 if (!p->expire || !p->pcp.count)
 474                         continue;
 475
 476                 /*
 477                  * We never drain zones local to this processor.
 478                  */
 479                 if (zone_to_nid(zone) == numa_node_id()) {
 480                         p->expire = 0;
 481                         continue;
 482                 }
 483
 484                 p->expire--;
 485                 if (p->expire)
 486                         continue;
 487
 488                 if (p->pcp.count) {
 489                         vm_activity = true;
 490                         drain_zone_pages(zone, &p->pcp);
 491                 }
 492 #endif
 493         }
 494
 495         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 496                 if (global_diff[i]) {
 497                         atomic_long_add(global_diff[i], &vm_stat[i]);
 498                         vm_activity = true;
 499                 }
 500
 501         return vm_activity;
 502
 503 }
 504
 505 /*
 506  * this is only called if !populated_zone(zone), which implies no other users of
 507  * pset->vm_stat_diff[] exsist.
 508  */
 509 void drain_zonestat(struct zone *zone, struct per_cpu_pageset *pset)
 510 {
 511         int i;
 512
 513         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 514                 if (pset->vm_stat_diff[i]) {
 515                         int v = pset->vm_stat_diff[i];
 516                         pset->vm_stat_diff[i] = 0;
 517                         atomic_long_add(v, &zone->vm_stat[i]);
 518                         atomic_long_add(v, &vm_stat[i]);
 519                 }
 520 }
 521 #endif
 522
 523 #ifdef CONFIG_NUMA
 524 /*
 525  * zonelist = the list of zones passed to the allocator
 526  * z        = the zone from which the allocation occurred.
 527  *
 528  * Must be called with interrupts disabled.
 529  *
 530  * When __GFP_OTHER_NODE is set assume the node of the preferred
 531  * zone is the local node. This is useful for daemons who allocate
 532  * memory on behalf of other processes.
 533  */
 534 void zone_statistics(struct zone *preferred_zone, struct zone *z, gfp_t flags)
 535 {
 536         if (z->zone_pgdat == preferred_zone->zone_pgdat) {
 537                 __inc_zone_state(z, NUMA_HIT);
 538         } else {
 539                 __inc_zone_state(z, NUMA_MISS);
 540                 __inc_zone_state(preferred_zone, NUMA_FOREIGN);
 541         }
 542         if (z->node == ((flags & __GFP_OTHER_NODE) ?
 543                         preferred_zone->node : numa_node_id()))
 544                 __inc_zone_state(z, NUMA_LOCAL);
 545         else
 546                 __inc_zone_state(z, NUMA_OTHER);
 547 }
 548 #endif
 549
 550 #ifdef CONFIG_COMPACTION
 551
 552 struct contig_page_info {
 553         unsigned long free_pages;
 554         unsigned long free_blocks_total;
 555         unsigned long free_blocks_suitable;
 556 };
 557
 558 /*
 559  * Calculate the number of free pages in a zone, how many contiguous
 560  * pages are free and how many are large enough to satisfy an allocation of
 561  * the target size. Note that this function makes no attempt to estimate
 562  * how many suitable free blocks there *might* be if MOVABLE pages were
 563  * migrated. Calculating that is possible, but expensive and can be
 564  * figured out from userspace
 565  */
 566 static void fill_contig_page_info(struct zone *zone,
 567                                 unsigned int suitable_order,
 568                                 struct contig_page_info *info)
 569 {
 570         unsigned int order;
 571
 572         info->free_pages = 0;
 573         info->free_blocks_total = 0;
 574         info->free_blocks_suitable = 0;
 575
 576         for (order = 0; order < MAX_ORDER; order++) {
 577                 unsigned long blocks;
 578
 579                 /* Count number of free blocks */
 580                 blocks = zone->free_area[order].nr_free;
 581                 info->free_blocks_total += blocks;
 582
 583                 /* Count free base pages */
 584                 info->free_pages += blocks << order;
 585
 586                 /* Count the suitable free blocks */
 587                 if (order >= suitable_order)
 588                         info->free_blocks_suitable += blocks <<
 589                                                 (order - suitable_order);
 590         }
 591 }
 592
 593 /*
 594  * A fragmentation index only makes sense if an allocation of a requested
 595  * size would fail. If that is true, the fragmentation index indicates
 596  * whether external fragmentation or a lack of memory was the problem.
 597  * The value can be used to determine if page reclaim or compaction
 598  * should be used
 599  */
 600 static int __fragmentation_index(unsigned int order, struct contig_page_info *info)
 601 {
 602         unsigned long requested = 1UL << order;
 603
 604         if (!info->free_blocks_total)
 605                 return 0;
 606
 607         /* Fragmentation index only makes sense when a request would fail */
 608         if (info->free_blocks_suitable)
 609                 return -1000;
 610
 611         /*
 612          * Index is between 0 and 1 so return within 3 decimal places
 613          *
 614          * 0 => allocation would fail due to lack of memory
 615          * 1 => allocation would fail due to fragmentation
 616          */
 617         return 1000 - div_u64( (1000+(div_u64(info->free_pages * 1000ULL, requested))), info->free_blocks_total);
 618 }
 619
 620 /* Same as __fragmentation index but allocs contig_page_info on stack */
 621 int fragmentation_index(struct zone *zone, unsigned int order)
 622 {
 623         struct contig_page_info info;
 624
 625         fill_contig_page_info(zone, order, &info);
 626         return __fragmentation_index(order, &info);
 627 }
 628 #endif
 629
 630 #if defined(CONFIG_PROC_FS) || defined(CONFIG_COMPACTION)
 631 #include <linux/proc_fs.h>
 632 #include <linux/seq_file.h>
 633
 634 static char * const migratetype_names[MIGRATE_TYPES] = {
 635         "Unmovable",
 636         "Reclaimable",
 637         "Movable",
 638         "Reserve",
 639 #ifdef CONFIG_CMA
 640         "CMA",
 641 #endif
 642 #ifdef CONFIG_MEMORY_ISOLATION
 643         "Isolate",
 644 #endif
 645 };
 646
 647 static void *frag_start(struct seq_file *m, loff_t *pos)
 648 {
 649         pg_data_t *pgdat;
 650         loff_t node = *pos;
 651         for (pgdat = first_online_pgdat();
 652              pgdat && node;
 653              pgdat = next_online_pgdat(pgdat))
 654                 --node;
 655
 656         return pgdat;
 657 }
 658
 659 static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
 660 {
 661         pg_data_t *pgdat = (pg_data_t *)arg;
 662
 663         (*pos)++;
 664         return next_online_pgdat(pgdat);
 665 }
 666
 667 static void frag_stop(struct seq_file *m, void *arg)
 668 {
 669 }
 670
 671 /* Walk all the zones in a node and print using a callback */
 672 static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat,
 673                 void (*print)(struct seq_file *m, pg_data_t *, struct zone *))
 674 {
 675         struct zone *zone;
 676         struct zone *node_zones = pgdat->node_zones;
 677         unsigned long flags;
 678
 679         for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
 680                 if (!populated_zone(zone))
 681                         continue;
 682
 683                 spin_lock_irqsave(&zone->lock, flags);
 684                 print(m, pgdat, zone);
 685                 spin_unlock_irqrestore(&zone->lock, flags);
 686         }
 687 }
 688 #endif
 689
 690 #if defined(CONFIG_PROC_FS) || defined(CONFIG_SYSFS) || defined(CONFIG_NUMA)
 691 #ifdef CONFIG_ZONE_DMA
 692 #define TEXT_FOR_DMA(xx) xx "_dma",
 693 #else
 694 #define TEXT_FOR_DMA(xx)
 695 #endif
 696
 697 #ifdef CONFIG_ZONE_DMA32
 698 #define TEXT_FOR_DMA32(xx) xx "_dma32",
 699 #else
 700 #define TEXT_FOR_DMA32(xx)
 701 #endif
 702
 703 #ifdef CONFIG_HIGHMEM
 704 #define TEXT_FOR_HIGHMEM(xx) xx "_high",
 705 #else
 706 #define TEXT_FOR_HIGHMEM(xx)
 707 #endif
 708
 709 #define TEXTS_FOR_ZONES(xx) TEXT_FOR_DMA(xx) TEXT_FOR_DMA32(xx) xx "_normal", \
 710                                         TEXT_FOR_HIGHMEM(xx) xx "_movable",
 711
 712 const char * const vmstat_text[] = {
 713         /* Zoned VM counters */
 714         "nr_free_pages",
 715         "nr_inactive_anon",
 716         "nr_active_anon",
 717         "nr_inactive_file",
 718         "nr_active_file",
 719         "nr_unevictable",
 720         "nr_mlock",
 721         "nr_anon_pages",
 722         "nr_mapped",
 723         "nr_file_pages",
 724         "nr_dirty",
 725         "nr_writeback",
 726         "nr_slab_reclaimable",
 727         "nr_slab_unreclaimable",
 728         "nr_page_table_pages",
 729         "nr_kernel_stack",
 730         "nr_unstable",
 731         "nr_bounce",
 732         "nr_vmscan_write",
 733         "nr_vmscan_immediate_reclaim",
 734         "nr_writeback_temp",
 735         "nr_isolated_anon",
 736         "nr_isolated_file",
 737         "nr_shmem",
 738         "nr_dirtied",
 739         "nr_written",
 740
 741 #ifdef CONFIG_NUMA
 742         "numa_hit",
 743         "numa_miss",
 744         "numa_foreign",
 745         "numa_interleave",
 746         "numa_local",
 747         "numa_other",
 748 #endif
 749         "nr_anon_transparent_hugepages",
 750         "nr_free_cma",
 751         "nr_dirty_threshold",
 752         "nr_dirty_background_threshold",
 753
 754 #ifdef CONFIG_VM_EVENT_COUNTERS
 755         "pgpgin",
 756         "pgpgout",
 757         "pswpin",
 758         "pswpout",
 759
 760         TEXTS_FOR_ZONES("pgalloc")
 761
 762         "pgfree",
 763         "pgactivate",
 764         "pgdeactivate",
 765
 766         "pgfault",
 767         "pgmajfault",
 768
 769         TEXTS_FOR_ZONES("pgrefill")
 770         TEXTS_FOR_ZONES("pgsteal_kswapd")
 771         TEXTS_FOR_ZONES("pgsteal_direct")
 772         TEXTS_FOR_ZONES("pgscan_kswapd")
 773         TEXTS_FOR_ZONES("pgscan_direct")
 774         "pgscan_direct_throttle",
 775
 776 #ifdef CONFIG_NUMA
 777         "zone_reclaim_failed",
 778 #endif
 779         "pginodesteal",
 780         "slabs_scanned",
 781         "kswapd_inodesteal",
 782         "kswapd_low_wmark_hit_quickly",
 783         "kswapd_high_wmark_hit_quickly",
 784         "pageoutrun",
 785         "allocstall",
 786
 787         "pgrotated",
 788
 789 #ifdef CONFIG_NUMA_BALANCING
 790         "numa_pte_updates",
 791         "numa_hint_faults",
 792         "numa_hint_faults_local",
 793         "numa_pages_migrated",
 794 #endif
 795 #ifdef CONFIG_MIGRATION
 796         "pgmigrate_success",
 797         "pgmigrate_fail",
 798 #endif
 799 #ifdef CONFIG_COMPACTION
 800         "compact_migrate_scanned",
 801         "compact_free_scanned",
 802         "compact_isolated",
 803         "compact_stall",
 804         "compact_fail",
 805         "compact_success",
 806 #endif
 807
 808 #ifdef CONFIG_HUGETLB_PAGE
 809         "htlb_buddy_alloc_success",
 810         "htlb_buddy_alloc_fail",
 811 #endif
 812         "unevictable_pgs_culled",
 813         "unevictable_pgs_scanned",
 814         "unevictable_pgs_rescued",
 815         "unevictable_pgs_mlocked",
 816         "unevictable_pgs_munlocked",
 817         "unevictable_pgs_cleared",
 818         "unevictable_pgs_stranded",
 819
 820 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 821         "thp_fault_alloc",
 822         "thp_fault_fallback",
 823         "thp_collapse_alloc",
 824         "thp_collapse_alloc_failed",
 825         "thp_split",
 826         "thp_zero_page_alloc",
 827         "thp_zero_page_alloc_failed",
 828 #endif
 829
 830 #endif /* CONFIG_VM_EVENTS_COUNTERS */
 831 };
 832 #endif /* CONFIG_PROC_FS || CONFIG_SYSFS || CONFIG_NUMA */
 833
 834
 835 #ifdef CONFIG_PROC_FS
 836 static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,
 837                                                 struct zone *zone)
 838 {
 839         int order;
 840
 841         seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
 842         for (order = 0; order < MAX_ORDER; ++order)
 843                 seq_printf(m, "%6lu ", zone->free_area[order].nr_free);
 844         seq_putc(m, '\n');
 845 }
 846
 847 /*
 848  * This walks the free areas for each zone.
 849  */
 850 static int frag_show(struct seq_file *m, void *arg)
 851 {
 852         pg_data_t *pgdat = (pg_data_t *)arg;
 853         walk_zones_in_node(m, pgdat, frag_show_print);
 854         return 0;
 855 }
 856
 857 static void pagetypeinfo_showfree_print(struct seq_file *m,
 858                                         pg_data_t *pgdat, struct zone *zone)
 859 {
 860         int order, mtype;
 861
 862         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++) {
 863                 seq_printf(m, "Node %4d, zone %8s, type %12s ",
 864                                         pgdat->node_id,
 865                                         zone->name,
 866                                         migratetype_names[mtype]);
 867                 for (order = 0; order < MAX_ORDER; ++order) {
 868                         unsigned long freecount = 0;
 869                         struct free_area *area;
 870                         struct list_head *curr;
 871
 872                         area = &(zone->free_area[order]);
 873
 874                         list_for_each(curr, &area->free_list[mtype])
 875                                 freecount++;
 876                         seq_printf(m, "%6lu ", freecount);
 877                 }
 878                 seq_putc(m, '\n');
 879         }
 880 }
 881
 882 /* Print out the free pages at each order for each migatetype */
 883 static int pagetypeinfo_showfree(struct seq_file *m, void *arg)
 884 {
 885         int order;
 886         pg_data_t *pgdat = (pg_data_t *)arg;
 887
 888         /* Print header */
 889         seq_printf(m, "%-43s ", "Free pages count per migrate type at order");
 890         for (order = 0; order < MAX_ORDER; ++order)
 891                 seq_printf(m, "%6d ", order);
 892         seq_putc(m, '\n');
 893
 894         walk_zones_in_node(m, pgdat, pagetypeinfo_showfree_print);
 895
 896         return 0;
 897 }
 898
 899 static void pagetypeinfo_showblockcount_print(struct seq_file *m,
 900                                         pg_data_t *pgdat, struct zone *zone)
 901 {
 902         int mtype;
 903         unsigned long pfn;
 904         unsigned long start_pfn = zone->zone_start_pfn;
 905         unsigned long end_pfn = zone_end_pfn(zone);
 906         unsigned long count[MIGRATE_TYPES] = { 0, };
 907
 908         for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
 909                 struct page *page;
 910
 911                 if (!pfn_valid(pfn))
 912                         continue;
 913
 914                 page = pfn_to_page(pfn);
 915
 916                 /* Watch for unexpected holes punched in the memmap */
 917                 if (!memmap_valid_within(pfn, page, zone))
 918                         continue;
 919
 920                 mtype = get_pageblock_migratetype(page);
 921
 922                 if (mtype < MIGRATE_TYPES)
 923                         count[mtype]++;
 924         }
 925
 926         /* Print counts */
 927         seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
 928         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
 929                 seq_printf(m, "%12lu ", count[mtype]);
 930         seq_putc(m, '\n');
 931 }
 932
 933 /* Print out the free pages at each order for each migratetype */
 934 static int pagetypeinfo_showblockcount(struct seq_file *m, void *arg)
 935 {
 936         int mtype;
 937         pg_data_t *pgdat = (pg_data_t *)arg;
 938
 939         seq_printf(m, "\n%-23s", "Number of blocks type ");
 940         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
 941                 seq_printf(m, "%12s ", migratetype_names[mtype]);
 942         seq_putc(m, '\n');
 943         walk_zones_in_node(m, pgdat, pagetypeinfo_showblockcount_print);
 944
 945         return 0;
 946 }
 947
 948 /*
 949  * This prints out statistics in relation to grouping pages by mobility.
 950  * It is expensive to collect so do not constantly read the file.
 951  */
 952 static int pagetypeinfo_show(struct seq_file *m, void *arg)
 953 {
 954         pg_data_t *pgdat = (pg_data_t *)arg;
 955
 956         /* check memoryless node */
 957         if (!node_state(pgdat->node_id, N_MEMORY))
 958                 return 0;
 959
 960         seq_printf(m, "Page block order: %d\n", pageblock_order);
 961         seq_printf(m, "Pages per block:  %lu\n", pageblock_nr_pages);
 962         seq_putc(m, '\n');
 963         pagetypeinfo_showfree(m, pgdat);
 964         pagetypeinfo_showblockcount(m, pgdat);
 965
 966         return 0;
 967 }
 968
 969 static const struct seq_operations fragmentation_op = {
 970         .start  = frag_start,
 971         .next   = frag_next,
 972         .stop   = frag_stop,
 973         .show   = frag_show,
 974 };
 975
 976 static int fragmentation_open(struct inode *inode, struct file *file)
 977 {
 978         return seq_open(file, &fragmentation_op);
 979 }
 980
 981 static const struct file_operations fragmentation_file_operations = {
 982         .open           = fragmentation_open,
 983         .read           = seq_read,
 984         .llseek         = seq_lseek,
 985         .release        = seq_release,
 986 };
 987
 988 static const struct seq_operations pagetypeinfo_op = {
 989         .start  = frag_start,
 990         .next   = frag_next,
 991         .stop   = frag_stop,
 992         .show   = pagetypeinfo_show,
 993 };
 994
 995 static int pagetypeinfo_open(struct inode *inode, struct file *file)
 996 {
 997         return seq_open(file, &pagetypeinfo_op);
 998 }
 999
1000 static const struct file_operations pagetypeinfo_file_ops = {
1001         .open           = pagetypeinfo_open,
1002         .read           = seq_read,
1003         .llseek         = seq_lseek,
1004         .release        = seq_release,
1005 };
1006
1007 static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
1008                                                         struct zone *zone)
1009 {
1010         int i;
1011         seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name);
1012         seq_printf(m,
1013                    "\n  pages free     %lu"
1014                    "\n        min      %lu"
1015                    "\n        low      %lu"
1016                    "\n        high     %lu"
1017                    "\n        scanned  %lu"
1018                    "\n        spanned  %lu"
1019                    "\n        present  %lu"
1020                    "\n        managed  %lu",
1021                    zone_page_state(zone, NR_FREE_PAGES),
1022                    min_wmark_pages(zone),
1023                    low_wmark_pages(zone),
1024                    high_wmark_pages(zone),
1025                    zone->pages_scanned,
1026                    zone->spanned_pages,
1027                    zone->present_pages,
1028                    zone->managed_pages);
1029
1030         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
1031                 seq_printf(m, "\n    %-12s %lu", vmstat_text[i],
1032                                 zone_page_state(zone, i));
1033
1034         seq_printf(m,
1035                    "\n        protection: (%lu",
1036                    zone->lowmem_reserve[0]);
1037         for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++)
1038                 seq_printf(m, ", %lu", zone->lowmem_reserve[i]);
1039         seq_printf(m,
1040                    ")"
1041                    "\n  pagesets");
1042         for_each_online_cpu(i) {
1043                 struct per_cpu_pageset *pageset;
1044
1045                 pageset = per_cpu_ptr(zone->pageset, i);
1046                 seq_printf(m,
1047                            "\n    cpu: %i"
1048                            "\n              count: %i"
1049                            "\n              high:  %i"
1050                            "\n              batch: %i",
1051                            i,
1052                            pageset->pcp.count,
1053                            pageset->pcp.high,
1054                            pageset->pcp.batch);
1055 #ifdef CONFIG_SMP
1056                 seq_printf(m, "\n  vm stats threshold: %d",
1057                                 pageset->stat_threshold);
1058 #endif
1059         }
1060         seq_printf(m,
1061                    "\n  all_unreclaimable: %u"
1062                    "\n  start_pfn:         %lu"
1063                    "\n  inactive_ratio:    %u",
1064                    zone->all_unreclaimable,
1065                    zone->zone_start_pfn,
1066                    zone->inactive_ratio);
1067         seq_putc(m, '\n');
1068 }
1069
1070 /*
1071  * Output information about zones in @pgdat.
1072  */
1073 static int zoneinfo_show(struct seq_file *m, void *arg)
1074 {
1075         pg_data_t *pgdat = (pg_data_t *)arg;
1076         walk_zones_in_node(m, pgdat, zoneinfo_show_print);
1077         return 0;
1078 }
1079
1080 static const struct seq_operations zoneinfo_op = {
1081         .start  = frag_start, /* iterate over all zones. The same as in
1082                                * fragmentation. */
1083         .next   = frag_next,
1084         .stop   = frag_stop,
1085         .show   = zoneinfo_show,
1086 };
1087
1088 static int zoneinfo_open(struct inode *inode, struct file *file)
1089 {
1090         return seq_open(file, &zoneinfo_op);
1091 }
1092
1093 static const struct file_operations proc_zoneinfo_file_operations = {
1094         .open           = zoneinfo_open,
1095         .read           = seq_read,
1096         .llseek         = seq_lseek,
1097         .release        = seq_release,
1098 };
1099
1100 enum writeback_stat_item {
1101         NR_DIRTY_THRESHOLD,
1102         NR_DIRTY_BG_THRESHOLD,
1103         NR_VM_WRITEBACK_STAT_ITEMS,
1104 };
1105
1106 static void *vmstat_start(struct seq_file *m, loff_t *pos)
1107 {
1108         unsigned long *v;
1109         int i, stat_items_size;
1110
1111         if (*pos >= ARRAY_SIZE(vmstat_text))
1112                 return NULL;
1113         stat_items_size = NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long) +
1114                           NR_VM_WRITEBACK_STAT_ITEMS * sizeof(unsigned long);
1115
1116 #ifdef CONFIG_VM_EVENT_COUNTERS
1117         stat_items_size += sizeof(struct vm_event_state);
1118 #endif
1119
1120         v = kmalloc(stat_items_size, GFP_KERNEL);
1121         m->private = v;
1122         if (!v)
1123                 return ERR_PTR(-ENOMEM);
1124         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
1125                 v[i] = global_page_state(i);
1126         v += NR_VM_ZONE_STAT_ITEMS;
1127
1128         global_dirty_limits(v + NR_DIRTY_BG_THRESHOLD,
1129                             v + NR_DIRTY_THRESHOLD);
1130         v += NR_VM_WRITEBACK_STAT_ITEMS;
1131
1132 #ifdef CONFIG_VM_EVENT_COUNTERS
1133         all_vm_events(v);
1134         v[PGPGIN] /= 2;         /* sectors -> kbytes */
1135         v[PGPGOUT] /= 2;
1136 #endif
1137         return (unsigned long *)m->private + *pos;
1138 }
1139
1140 static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)
1141 {
1142         (*pos)++;
1143         if (*pos >= ARRAY_SIZE(vmstat_text))
1144                 return NULL;
1145         return (unsigned long *)m->private + *pos;
1146 }
1147
1148 static int vmstat_show(struct seq_file *m, void *arg)
1149 {
1150         unsigned long *l = arg;
1151         unsigned long off = l - (unsigned long *)m->private;
1152
1153         seq_printf(m, "%s %lu\n", vmstat_text[off], *l);
1154         return 0;
1155 }
1156
1157 static void vmstat_stop(struct seq_file *m, void *arg)
1158 {
1159         kfree(m->private);
1160         m->private = NULL;
1161 }
1162
1163 static const struct seq_operations vmstat_op = {
1164         .start  = vmstat_start,
1165         .next   = vmstat_next,
1166         .stop   = vmstat_stop,
1167         .show   = vmstat_show,
1168 };
1169
1170 static int vmstat_open(struct inode *inode, struct file *file)
1171 {
1172         return seq_open(file, &vmstat_op);
1173 }
1174
1175 static const struct file_operations proc_vmstat_file_operations = {
1176         .open           = vmstat_open,
1177         .read           = seq_read,
1178         .llseek         = seq_lseek,
1179         .release        = seq_release,
1180 };
1181 #endif /* CONFIG_PROC_FS */
1182
1183 #ifdef CONFIG_SMP
1184 static DEFINE_PER_CPU(struct delayed_work, vmstat_work);
1185 int sysctl_stat_interval __read_mostly = HZ;
1186 static struct cpumask vmstat_off_cpus;
1187 struct delayed_work vmstat_monitor_work;
1188
1189 static inline bool need_vmstat(int cpu)
1190 {
1191         struct zone *zone;
1192         int i;
1193
1194         for_each_populated_zone(zone) {
1195                 struct per_cpu_pageset *p;
1196
1197                 p = per_cpu_ptr(zone->pageset, cpu);
1198
1199                 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
1200                         if (p->vm_stat_diff[i])
1201                                 return true;
1202
1203                 if (zone_to_nid(zone) != numa_node_id() && p->pcp.count)
1204                         return true;
1205         }
1206
1207         return false;
1208 }
1209
1210 static void vmstat_update(struct work_struct *w);
1211
1212 static void start_cpu_timer(int cpu)
1213 {
1214         struct delayed_work *work = &per_cpu(vmstat_work, cpu);
1215
1216         cpumask_clear_cpu(cpu, &vmstat_off_cpus);
1217         schedule_delayed_work_on(cpu, work, __round_jiffies_relative(HZ, cpu));
1218 }
1219
1220 static void __cpuinit setup_cpu_timer(int cpu)
1221 {
1222         struct delayed_work *work = &per_cpu(vmstat_work, cpu);
1223
1224         INIT_DEFERRABLE_WORK(work, vmstat_update);
1225         start_cpu_timer(cpu);
1226 }
1227
1228 static void vmstat_update_monitor(struct work_struct *w)
1229 {
1230         int cpu;
1231
1232         for_each_cpu_and(cpu, &vmstat_off_cpus, cpu_online_mask)
1233                 if (need_vmstat(cpu))
1234                         start_cpu_timer(cpu);
1235
1236         queue_delayed_work(system_unbound_wq, &vmstat_monitor_work,
1237                 round_jiffies_relative(sysctl_stat_interval));
1238 }
1239
1240
1241 static void vmstat_update(struct work_struct *w)
1242 {
1243         int cpu = smp_processor_id();
1244
1245         if (likely(refresh_cpu_vm_stats(cpu)))
1246                 schedule_delayed_work(&__get_cpu_var(vmstat_work),
1247                                 round_jiffies_relative(sysctl_stat_interval));
1248         else
1249                 cpumask_set_cpu(cpu, &vmstat_off_cpus);
1250 }
1251
1252 /*
1253  * Use the cpu notifier to insure that the thresholds are recalculated
1254  * when necessary.
1255  */
1256 static int __cpuinit vmstat_cpuup_callback(struct notifier_block *nfb,
1257                 unsigned long action,
1258                 void *hcpu)
1259 {
1260         long cpu = (long)hcpu;
1261
1262         switch (action) {
1263         case CPU_ONLINE:
1264         case CPU_ONLINE_FROZEN:
1265                 refresh_zone_stat_thresholds();
1266                 setup_cpu_timer(cpu);
1267                 node_set_state(cpu_to_node(cpu), N_CPU);
1268                 break;
1269         case CPU_DOWN_PREPARE:
1270         case CPU_DOWN_PREPARE_FROZEN:
1271                 if (!cpumask_test_cpu(cpu, &vmstat_off_cpus)) {
1272                         cancel_delayed_work_sync(&per_cpu(vmstat_work, cpu));
1273                         per_cpu(vmstat_work, cpu).work.func = NULL;
1274                 }
1275                 break;
1276         case CPU_DOWN_FAILED:
1277         case CPU_DOWN_FAILED_FROZEN:
1278                 setup_cpu_timer(cpu);
1279                 break;
1280         case CPU_DEAD:
1281         case CPU_DEAD_FROZEN:
1282                 refresh_zone_stat_thresholds();
1283                 break;
1284         default:
1285                 break;
1286         }
1287         return NOTIFY_OK;
1288 }
1289
1290 static struct notifier_block __cpuinitdata vmstat_notifier =
1291         { &vmstat_cpuup_callback, NULL, 0 };
1292 #endif
1293
1294 static int __init setup_vmstat(void)
1295 {
1296 #ifdef CONFIG_SMP
1297         int cpu;
1298
1299         register_cpu_notifier(&vmstat_notifier);
1300
1301         INIT_DEFERRABLE_WORK(&vmstat_monitor_work,
1302                                 vmstat_update_monitor);
1303         queue_delayed_work(system_unbound_wq,
1304                                 &vmstat_monitor_work,
1305                                 round_jiffies_relative(HZ));
1306
1307         for_each_online_cpu(cpu)
1308                 setup_cpu_timer(cpu);
1309 #endif
1310 #ifdef CONFIG_PROC_FS
1311         proc_create("buddyinfo", S_IRUGO, NULL, &fragmentation_file_operations);
1312         proc_create("pagetypeinfo", S_IRUGO, NULL, &pagetypeinfo_file_ops);
1313         proc_create("vmstat", S_IRUGO, NULL, &proc_vmstat_file_operations);
1314         proc_create("zoneinfo", S_IRUGO, NULL, &proc_zoneinfo_file_operations);
1315 #endif
1316         return 0;
1317 }
1318 module_init(setup_vmstat)
1319
1320 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)
1321 #include <linux/debugfs.h>
1322
1323
1324 /*
1325  * Return an index indicating how much of the available free memory is
1326  * unusable for an allocation of the requested size.
1327  */
1328 static int unusable_free_index(unsigned int order,
1329                                 struct contig_page_info *info)
1330 {
1331         /* No free memory is interpreted as all free memory is unusable */
1332         if (info->free_pages == 0)
1333                 return 1000;
1334
1335         /*
1336          * Index should be a value between 0 and 1. Return a value to 3
1337          * decimal places.
1338          *
1339          * 0 => no fragmentation
1340          * 1 => high fragmentation
1341          */
1342         return div_u64((info->free_pages - (info->free_blocks_suitable << order)) * 1000ULL, info->free_pages);
1343
1344 }
1345
1346 static void unusable_show_print(struct seq_file *m,
1347                                         pg_data_t *pgdat, struct zone *zone)
1348 {
1349         unsigned int order;
1350         int index;
1351         struct contig_page_info info;
1352
1353         seq_printf(m, "Node %d, zone %8s ",
1354                                 pgdat->node_id,
1355                                 zone->name);
1356         for (order = 0; order < MAX_ORDER; ++order) {
1357                 fill_contig_page_info(zone, order, &info);
1358                 index = unusable_free_index(order, &info);
1359                 seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
1360         }
1361
1362         seq_putc(m, '\n');
1363 }
1364
1365 /*
1366  * Display unusable free space index
1367  *
1368  * The unusable free space index measures how much of the available free
1369  * memory cannot be used to satisfy an allocation of a given size and is a
1370  * value between 0 and 1. The higher the value, the more of free memory is
1371  * unusable and by implication, the worse the external fragmentation is. This
1372  * can be expressed as a percentage by multiplying by 100.
1373  */
1374 static int unusable_show(struct seq_file *m, void *arg)
1375 {
1376         pg_data_t *pgdat = (pg_data_t *)arg;
1377
1378         /* check memoryless node */
1379         if (!node_state(pgdat->node_id, N_MEMORY))
1380                 return 0;
1381
1382         walk_zones_in_node(m, pgdat, unusable_show_print);
1383
1384         return 0;
1385 }
1386
1387 static const struct seq_operations unusable_op = {
1388         .start  = frag_start,
1389         .next   = frag_next,
1390         .stop   = frag_stop,
1391         .show   = unusable_show,
1392 };
1393
1394 static int unusable_open(struct inode *inode, struct file *file)
1395 {
1396         return seq_open(file, &unusable_op);
1397 }
1398
1399 static const struct file_operations unusable_file_ops = {
1400         .open           = unusable_open,
1401         .read           = seq_read,
1402         .llseek         = seq_lseek,
1403         .release        = seq_release,
1404 };
1405
1406 static void extfrag_show_print(struct seq_file *m,
1407                                         pg_data_t *pgdat, struct zone *zone)
1408 {
1409         unsigned int order;
1410         int index;
1411
1412         /* Alloc on stack as interrupts are disabled for zone walk */
1413         struct contig_page_info info;
1414
1415         seq_printf(m, "Node %d, zone %8s ",
1416                                 pgdat->node_id,
1417                                 zone->name);
1418         for (order = 0; order < MAX_ORDER; ++order) {
1419                 fill_contig_page_info(zone, order, &info);
1420                 index = __fragmentation_index(order, &info);
1421                 seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
1422         }
1423
1424         seq_putc(m, '\n');
1425 }
1426
1427 /*
1428  * Display fragmentation index for orders that allocations would fail for
1429  */
1430 static int extfrag_show(struct seq_file *m, void *arg)
1431 {
1432         pg_data_t *pgdat = (pg_data_t *)arg;
1433
1434         walk_zones_in_node(m, pgdat, extfrag_show_print);
1435
1436         return 0;
1437 }
1438
1439 static const struct seq_operations extfrag_op = {
1440         .start  = frag_start,
1441         .next   = frag_next,
1442         .stop   = frag_stop,
1443         .show   = extfrag_show,
1444 };
1445
1446 static int extfrag_open(struct inode *inode, struct file *file)
1447 {
1448         return seq_open(file, &extfrag_op);
1449 }
1450
1451 static const struct file_operations extfrag_file_ops = {
1452         .open           = extfrag_open,
1453         .read           = seq_read,
1454         .llseek         = seq_lseek,
1455         .release        = seq_release,
1456 };
1457
1458 static int __init extfrag_debug_init(void)
1459 {
1460         struct dentry *extfrag_debug_root;
1461
1462         extfrag_debug_root = debugfs_create_dir("extfrag", NULL);
1463         if (!extfrag_debug_root)
1464                 return -ENOMEM;
1465
1466         if (!debugfs_create_file("unusable_index", 0444,
1467                         extfrag_debug_root, NULL, &unusable_file_ops))
1468                 goto fail;
1469
1470         if (!debugfs_create_file("extfrag_index", 0444,
1471                         extfrag_debug_root, NULL, &extfrag_file_ops))
1472                 goto fail;
1473
1474         return 0;
1475 fail:
1476         debugfs_remove_recursive(extfrag_debug_root);
1477         return -ENOMEM;
1478 }
1479
1480 module_init(extfrag_debug_init);
1481 #endif