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  *  Copyright (C) 2008-2014 Christoph Lameter
  11  */
  12 #include <linux/fs.h>
  13 #include <linux/mm.h>
  14 #include <linux/err.h>
  15 #include <linux/module.h>
  16 #include <linux/slab.h>
  17 #include <linux/cpu.h>
  18 #include <linux/cpumask.h>
  19 #include <linux/vmstat.h>
  20 #include <linux/proc_fs.h>
  21 #include <linux/seq_file.h>
  22 #include <linux/debugfs.h>
  23 #include <linux/sched.h>
  24 #include <linux/math64.h>
  25 #include <linux/writeback.h>
  26 #include <linux/compaction.h>
  27 #include <linux/mm_inline.h>
  28 #include <linux/page_ext.h>
  29 #include <linux/page_owner.h>
  30
  31 #include "internal.h"
  32
  33 #ifdef CONFIG_VM_EVENT_COUNTERS
  34 DEFINE_PER_CPU(struct vm_event_state, vm_event_states) = {{0}};
  35 EXPORT_PER_CPU_SYMBOL(vm_event_states);
  36
  37 static void sum_vm_events(unsigned long *ret)
  38 {
  39         int cpu;
  40         int i;
  41
  42         memset(ret, 0, NR_VM_EVENT_ITEMS * sizeof(unsigned long));
  43
  44         for_each_online_cpu(cpu) {
  45                 struct vm_event_state *this = &per_cpu(vm_event_states, cpu);
  46
  47                 for (i = 0; i < NR_VM_EVENT_ITEMS; i++)
  48                         ret[i] += this->event[i];
  49         }
  50 }
  51
  52 /*
  53  * Accumulate the vm event counters across all CPUs.
  54  * The result is unavoidably approximate - it can change
  55  * during and after execution of this function.
  56 */
  57 void all_vm_events(unsigned long *ret)
  58 {
  59         get_online_cpus();
  60         sum_vm_events(ret);
  61         put_online_cpus();
  62 }
  63 EXPORT_SYMBOL_GPL(all_vm_events);
  64
  65 /*
  66  * Fold the foreign cpu events into our own.
  67  *
  68  * This is adding to the events on one processor
  69  * but keeps the global counts constant.
  70  */
  71 void vm_events_fold_cpu(int cpu)
  72 {
  73         struct vm_event_state *fold_state = &per_cpu(vm_event_states, cpu);
  74         int i;
  75
  76         for (i = 0; i < NR_VM_EVENT_ITEMS; i++) {
  77                 count_vm_events(i, fold_state->event[i]);
  78                 fold_state->event[i] = 0;
  79         }
  80 }
  81
  82 #endif /* CONFIG_VM_EVENT_COUNTERS */
  83
  84 /*
  85  * Manage combined zone based / global counters
  86  *
  87  * vm_stat contains the global counters
  88  */
  89 atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS] __cacheline_aligned_in_smp;
  90 EXPORT_SYMBOL(vm_stat);
  91
  92 #ifdef CONFIG_SMP
  93
  94 int calculate_pressure_threshold(struct zone *zone)
  95 {
  96         int threshold;
  97         int watermark_distance;
  98
  99         /*
 100          * As vmstats are not up to date, there is drift between the estimated
 101          * and real values. For high thresholds and a high number of CPUs, it
 102          * is possible for the min watermark to be breached while the estimated
 103          * value looks fine. The pressure threshold is a reduced value such
 104          * that even the maximum amount of drift will not accidentally breach
 105          * the min watermark
 106          */
 107         watermark_distance = low_wmark_pages(zone) - min_wmark_pages(zone);
 108         threshold = max(1, (int)(watermark_distance / num_online_cpus()));
 109
 110         /*
 111          * Maximum threshold is 125
 112          */
 113         threshold = min(125, threshold);
 114
 115         return threshold;
 116 }
 117
 118 int calculate_normal_threshold(struct zone *zone)
 119 {
 120         int threshold;
 121         int mem;        /* memory in 128 MB units */
 122
 123         /*
 124          * The threshold scales with the number of processors and the amount
 125          * of memory per zone. More memory means that we can defer updates for
 126          * longer, more processors could lead to more contention.
 127          * fls() is used to have a cheap way of logarithmic scaling.
 128          *
 129          * Some sample thresholds:
 130          *
 131          * Threshold    Processors      (fls)   Zonesize        fls(mem+1)
 132          * ------------------------------------------------------------------
 133          * 8            1               1       0.9-1 GB        4
 134          * 16           2               2       0.9-1 GB        4
 135          * 20           2               2       1-2 GB          5
 136          * 24           2               2       2-4 GB          6
 137          * 28           2               2       4-8 GB          7
 138          * 32           2               2       8-16 GB         8
 139          * 4            2               2       <128M           1
 140          * 30           4               3       2-4 GB          5
 141          * 48           4               3       8-16 GB         8
 142          * 32           8               4       1-2 GB          4
 143          * 32           8               4       0.9-1GB         4
 144          * 10           16              5       <128M           1
 145          * 40           16              5       900M            4
 146          * 70           64              7       2-4 GB          5
 147          * 84           64              7       4-8 GB          6
 148          * 108          512             9       4-8 GB          6
 149          * 125          1024            10      8-16 GB         8
 150          * 125          1024            10      16-32 GB        9
 151          */
 152
 153         mem = zone->managed_pages >> (27 - PAGE_SHIFT);
 154
 155         threshold = 2 * fls(num_online_cpus()) * (1 + fls(mem));
 156
 157         /*
 158          * Maximum threshold is 125
 159          */
 160         threshold = min(125, threshold);
 161
 162         return threshold;
 163 }
 164
 165 /*
 166  * Refresh the thresholds for each zone.
 167  */
 168 void refresh_zone_stat_thresholds(void)
 169 {
 170         struct zone *zone;
 171         int cpu;
 172         int threshold;
 173
 174         for_each_populated_zone(zone) {
 175                 unsigned long max_drift, tolerate_drift;
 176
 177                 threshold = calculate_normal_threshold(zone);
 178
 179                 for_each_online_cpu(cpu)
 180                         per_cpu_ptr(zone->pageset, cpu)->stat_threshold
 181                                                         = threshold;
 182
 183                 /*
 184                  * Only set percpu_drift_mark if there is a danger that
 185                  * NR_FREE_PAGES reports the low watermark is ok when in fact
 186                  * the min watermark could be breached by an allocation
 187                  */
 188                 tolerate_drift = low_wmark_pages(zone) - min_wmark_pages(zone);
 189                 max_drift = num_online_cpus() * threshold;
 190                 if (max_drift > tolerate_drift)
 191                         zone->percpu_drift_mark = high_wmark_pages(zone) +
 192                                         max_drift;
 193         }
 194 }
 195
 196 void set_pgdat_percpu_threshold(pg_data_t *pgdat,
 197                                 int (*calculate_pressure)(struct zone *))
 198 {
 199         struct zone *zone;
 200         int cpu;
 201         int threshold;
 202         int i;
 203
 204         for (i = 0; i < pgdat->nr_zones; i++) {
 205                 zone = &pgdat->node_zones[i];
 206                 if (!zone->percpu_drift_mark)
 207                         continue;
 208
 209                 threshold = (*calculate_pressure)(zone);
 210                 for_each_online_cpu(cpu)
 211                         per_cpu_ptr(zone->pageset, cpu)->stat_threshold
 212                                                         = threshold;
 213         }
 214 }
 215
 216 /*
 217  * For use when we know that interrupts are disabled,
 218  * or when we know that preemption is disabled and that
 219  * particular counter cannot be updated from interrupt context.
 220  */
 221 void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 222                                 int delta)
 223 {
 224         struct per_cpu_pageset __percpu *pcp = zone->pageset;
 225         s8 __percpu *p = pcp->vm_stat_diff + item;
 226         long x;
 227         long t;
 228
 229         x = delta + __this_cpu_read(*p);
 230
 231         t = __this_cpu_read(pcp->stat_threshold);
 232
 233         if (unlikely(x > t || x < -t)) {
 234                 zone_page_state_add(x, zone, item);
 235                 x = 0;
 236         }
 237         __this_cpu_write(*p, x);
 238 }
 239 EXPORT_SYMBOL(__mod_zone_page_state);
 240
 241 /*
 242  * Optimized increment and decrement functions.
 243  *
 244  * These are only for a single page and therefore can take a struct page *
 245  * argument instead of struct zone *. This allows the inclusion of the code
 246  * generated for page_zone(page) into the optimized functions.
 247  *
 248  * No overflow check is necessary and therefore the differential can be
 249  * incremented or decremented in place which may allow the compilers to
 250  * generate better code.
 251  * The increment or decrement is known and therefore one boundary check can
 252  * be omitted.
 253  *
 254  * NOTE: These functions are very performance sensitive. Change only
 255  * with care.
 256  *
 257  * Some processors have inc/dec instructions that are atomic vs an interrupt.
 258  * However, the code must first determine the differential location in a zone
 259  * based on the processor number and then inc/dec the counter. There is no
 260  * guarantee without disabling preemption that the processor will not change
 261  * in between and therefore the atomicity vs. interrupt cannot be exploited
 262  * in a useful way here.
 263  */
 264 void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
 265 {
 266         struct per_cpu_pageset __percpu *pcp = zone->pageset;
 267         s8 __percpu *p = pcp->vm_stat_diff + item;
 268         s8 v, t;
 269
 270         v = __this_cpu_inc_return(*p);
 271         t = __this_cpu_read(pcp->stat_threshold);
 272         if (unlikely(v > t)) {
 273                 s8 overstep = t >> 1;
 274
 275                 zone_page_state_add(v + overstep, zone, item);
 276                 __this_cpu_write(*p, -overstep);
 277         }
 278 }
 279
 280 void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
 281 {
 282         __inc_zone_state(page_zone(page), item);
 283 }
 284 EXPORT_SYMBOL(__inc_zone_page_state);
 285
 286 void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
 287 {
 288         struct per_cpu_pageset __percpu *pcp = zone->pageset;
 289         s8 __percpu *p = pcp->vm_stat_diff + item;
 290         s8 v, t;
 291
 292         v = __this_cpu_dec_return(*p);
 293         t = __this_cpu_read(pcp->stat_threshold);
 294         if (unlikely(v < - t)) {
 295                 s8 overstep = t >> 1;
 296
 297                 zone_page_state_add(v - overstep, zone, item);
 298                 __this_cpu_write(*p, overstep);
 299         }
 300 }
 301
 302 void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
 303 {
 304         __dec_zone_state(page_zone(page), item);
 305 }
 306 EXPORT_SYMBOL(__dec_zone_page_state);
 307
 308 #ifdef CONFIG_HAVE_CMPXCHG_LOCAL
 309 /*
 310  * If we have cmpxchg_local support then we do not need to incur the overhead
 311  * that comes with local_irq_save/restore if we use this_cpu_cmpxchg.
 312  *
 313  * mod_state() modifies the zone counter state through atomic per cpu
 314  * operations.
 315  *
 316  * Overstep mode specifies how overstep should handled:
 317  *     0       No overstepping
 318  *     1       Overstepping half of threshold
 319  *     -1      Overstepping minus half of threshold
 320 */
 321 static inline void mod_state(struct zone *zone,
 322        enum zone_stat_item item, int delta, int overstep_mode)
 323 {
 324         struct per_cpu_pageset __percpu *pcp = zone->pageset;
 325         s8 __percpu *p = pcp->vm_stat_diff + item;
 326         long o, n, t, z;
 327
 328         do {
 329                 z = 0;  /* overflow to zone counters */
 330
 331                 /*
 332                  * The fetching of the stat_threshold is racy. We may apply
 333                  * a counter threshold to the wrong the cpu if we get
 334                  * rescheduled while executing here. However, the next
 335                  * counter update will apply the threshold again and
 336                  * therefore bring the counter under the threshold again.
 337                  *
 338                  * Most of the time the thresholds are the same anyways
 339                  * for all cpus in a zone.
 340                  */
 341                 t = this_cpu_read(pcp->stat_threshold);
 342
 343                 o = this_cpu_read(*p);
 344                 n = delta + o;
 345
 346                 if (n > t || n < -t) {
 347                         int os = overstep_mode * (t >> 1) ;
 348
 349                         /* Overflow must be added to zone counters */
 350                         z = n + os;
 351                         n = -os;
 352                 }
 353         } while (this_cpu_cmpxchg(*p, o, n) != o);
 354
 355         if (z)
 356                 zone_page_state_add(z, zone, item);
 357 }
 358
 359 void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 360                                         int delta)
 361 {
 362         mod_state(zone, item, delta, 0);
 363 }
 364 EXPORT_SYMBOL(mod_zone_page_state);
 365
 366 void inc_zone_state(struct zone *zone, enum zone_stat_item item)
 367 {
 368         mod_state(zone, item, 1, 1);
 369 }
 370
 371 void inc_zone_page_state(struct page *page, enum zone_stat_item item)
 372 {
 373         mod_state(page_zone(page), item, 1, 1);
 374 }
 375 EXPORT_SYMBOL(inc_zone_page_state);
 376
 377 void dec_zone_page_state(struct page *page, enum zone_stat_item item)
 378 {
 379         mod_state(page_zone(page), item, -1, -1);
 380 }
 381 EXPORT_SYMBOL(dec_zone_page_state);
 382 #else
 383 /*
 384  * Use interrupt disable to serialize counter updates
 385  */
 386 void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 387                                         int delta)
 388 {
 389         unsigned long flags;
 390
 391         local_irq_save(flags);
 392         __mod_zone_page_state(zone, item, delta);
 393         local_irq_restore(flags);
 394 }
 395 EXPORT_SYMBOL(mod_zone_page_state);
 396
 397 void inc_zone_state(struct zone *zone, enum zone_stat_item item)
 398 {
 399         unsigned long flags;
 400
 401         local_irq_save(flags);
 402         __inc_zone_state(zone, item);
 403         local_irq_restore(flags);
 404 }
 405
 406 void inc_zone_page_state(struct page *page, enum zone_stat_item item)
 407 {
 408         unsigned long flags;
 409         struct zone *zone;
 410
 411         zone = page_zone(page);
 412         local_irq_save(flags);
 413         __inc_zone_state(zone, item);
 414         local_irq_restore(flags);
 415 }
 416 EXPORT_SYMBOL(inc_zone_page_state);
 417
 418 void dec_zone_page_state(struct page *page, enum zone_stat_item item)
 419 {
 420         unsigned long flags;
 421
 422         local_irq_save(flags);
 423         __dec_zone_page_state(page, item);
 424         local_irq_restore(flags);
 425 }
 426 EXPORT_SYMBOL(dec_zone_page_state);
 427 #endif
 428
 429
 430 /*
 431  * Fold a differential into the global counters.
 432  * Returns the number of counters updated.
 433  */
 434 static int fold_diff(int *diff)
 435 {
 436         int i;
 437         int changes = 0;
 438
 439         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 440                 if (diff[i]) {
 441                         atomic_long_add(diff[i], &vm_stat[i]);
 442                         changes++;
 443         }
 444         return changes;
 445 }
 446
 447 /*
 448  * Update the zone counters for the current cpu.
 449  *
 450  * Note that refresh_cpu_vm_stats strives to only access
 451  * node local memory. The per cpu pagesets on remote zones are placed
 452  * in the memory local to the processor using that pageset. So the
 453  * loop over all zones will access a series of cachelines local to
 454  * the processor.
 455  *
 456  * The call to zone_page_state_add updates the cachelines with the
 457  * statistics in the remote zone struct as well as the global cachelines
 458  * with the global counters. These could cause remote node cache line
 459  * bouncing and will have to be only done when necessary.
 460  *
 461  * The function returns the number of global counters updated.
 462  */
 463 static int refresh_cpu_vm_stats(void)
 464 {
 465         struct zone *zone;
 466         int i;
 467         int global_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
 468         int changes = 0;
 469
 470         for_each_populated_zone(zone) {
 471                 struct per_cpu_pageset __percpu *p = zone->pageset;
 472
 473                 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
 474                         int v;
 475
 476                         v = this_cpu_xchg(p->vm_stat_diff[i], 0);
 477                         if (v) {
 478
 479                                 atomic_long_add(v, &zone->vm_stat[i]);
 480                                 global_diff[i] += v;
 481 #ifdef CONFIG_NUMA
 482                                 /* 3 seconds idle till flush */
 483                                 __this_cpu_write(p->expire, 3);
 484 #endif
 485                         }
 486                 }
 487                 cond_resched();
 488 #ifdef CONFIG_NUMA
 489                 /*
 490                  * Deal with draining the remote pageset of this
 491                  * processor
 492                  *
 493                  * Check if there are pages remaining in this pageset
 494                  * if not then there is nothing to expire.
 495                  */
 496                 if (!__this_cpu_read(p->expire) ||
 497                                !__this_cpu_read(p->pcp.count))
 498                         continue;
 499
 500                 /*
 501                  * We never drain zones local to this processor.
 502                  */
 503                 if (zone_to_nid(zone) == numa_node_id()) {
 504                         __this_cpu_write(p->expire, 0);
 505                         continue;
 506                 }
 507
 508                 if (__this_cpu_dec_return(p->expire))
 509                         continue;
 510
 511                 if (__this_cpu_read(p->pcp.count)) {
 512                         drain_zone_pages(zone, this_cpu_ptr(&p->pcp));
 513                         changes++;
 514                 }
 515 #endif
 516         }
 517         changes += fold_diff(global_diff);
 518         return changes;
 519 }
 520
 521 /*
 522  * Fold the data for an offline cpu into the global array.
 523  * There cannot be any access by the offline cpu and therefore
 524  * synchronization is simplified.
 525  */
 526 void cpu_vm_stats_fold(int cpu)
 527 {
 528         struct zone *zone;
 529         int i;
 530         int global_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
 531
 532         for_each_populated_zone(zone) {
 533                 struct per_cpu_pageset *p;
 534
 535                 p = per_cpu_ptr(zone->pageset, cpu);
 536
 537                 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 538                         if (p->vm_stat_diff[i]) {
 539                                 int v;
 540
 541                                 v = p->vm_stat_diff[i];
 542                                 p->vm_stat_diff[i] = 0;
 543                                 atomic_long_add(v, &zone->vm_stat[i]);
 544                                 global_diff[i] += v;
 545                         }
 546         }
 547
 548         fold_diff(global_diff);
 549 }
 550
 551 /*
 552  * this is only called if !populated_zone(zone), which implies no other users of
 553  * pset->vm_stat_diff[] exsist.
 554  */
 555 void drain_zonestat(struct zone *zone, struct per_cpu_pageset *pset)
 556 {
 557         int i;
 558
 559         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 560                 if (pset->vm_stat_diff[i]) {
 561                         int v = pset->vm_stat_diff[i];
 562                         pset->vm_stat_diff[i] = 0;
 563                         atomic_long_add(v, &zone->vm_stat[i]);
 564                         atomic_long_add(v, &vm_stat[i]);
 565                 }
 566 }
 567 #endif
 568
 569 #ifdef CONFIG_NUMA
 570 /*
 571  * zonelist = the list of zones passed to the allocator
 572  * z        = the zone from which the allocation occurred.
 573  *
 574  * Must be called with interrupts disabled.
 575  *
 576  * When __GFP_OTHER_NODE is set assume the node of the preferred
 577  * zone is the local node. This is useful for daemons who allocate
 578  * memory on behalf of other processes.
 579  */
 580 void zone_statistics(struct zone *preferred_zone, struct zone *z, gfp_t flags)
 581 {
 582         if (z->zone_pgdat == preferred_zone->zone_pgdat) {
 583                 __inc_zone_state(z, NUMA_HIT);
 584         } else {
 585                 __inc_zone_state(z, NUMA_MISS);
 586                 __inc_zone_state(preferred_zone, NUMA_FOREIGN);
 587         }
 588         if (z->node == ((flags & __GFP_OTHER_NODE) ?
 589                         preferred_zone->node : numa_node_id()))
 590                 __inc_zone_state(z, NUMA_LOCAL);
 591         else
 592                 __inc_zone_state(z, NUMA_OTHER);
 593 }
 594 #endif
 595
 596 #ifdef CONFIG_COMPACTION
 597
 598 struct contig_page_info {
 599         unsigned long free_pages;
 600         unsigned long free_blocks_total;
 601         unsigned long free_blocks_suitable;
 602 };
 603
 604 /*
 605  * Calculate the number of free pages in a zone, how many contiguous
 606  * pages are free and how many are large enough to satisfy an allocation of
 607  * the target size. Note that this function makes no attempt to estimate
 608  * how many suitable free blocks there *might* be if MOVABLE pages were
 609  * migrated. Calculating that is possible, but expensive and can be
 610  * figured out from userspace
 611  */
 612 static void fill_contig_page_info(struct zone *zone,
 613                                 unsigned int suitable_order,
 614                                 struct contig_page_info *info)
 615 {
 616         unsigned int order;
 617
 618         info->free_pages = 0;
 619         info->free_blocks_total = 0;
 620         info->free_blocks_suitable = 0;
 621
 622         for (order = 0; order < MAX_ORDER; order++) {
 623                 unsigned long blocks;
 624
 625                 /* Count number of free blocks */
 626                 blocks = zone->free_area[order].nr_free;
 627                 info->free_blocks_total += blocks;
 628
 629                 /* Count free base pages */
 630                 info->free_pages += blocks << order;
 631
 632                 /* Count the suitable free blocks */
 633                 if (order >= suitable_order)
 634                         info->free_blocks_suitable += blocks <<
 635                                                 (order - suitable_order);
 636         }
 637 }
 638
 639 /*
 640  * A fragmentation index only makes sense if an allocation of a requested
 641  * size would fail. If that is true, the fragmentation index indicates
 642  * whether external fragmentation or a lack of memory was the problem.
 643  * The value can be used to determine if page reclaim or compaction
 644  * should be used
 645  */
 646 static int __fragmentation_index(unsigned int order, struct contig_page_info *info)
 647 {
 648         unsigned long requested = 1UL << order;
 649
 650         if (!info->free_blocks_total)
 651                 return 0;
 652
 653         /* Fragmentation index only makes sense when a request would fail */
 654         if (info->free_blocks_suitable)
 655                 return -1000;
 656
 657         /*
 658          * Index is between 0 and 1 so return within 3 decimal places
 659          *
 660          * 0 => allocation would fail due to lack of memory
 661          * 1 => allocation would fail due to fragmentation
 662          */
 663         return 1000 - div_u64( (1000+(div_u64(info->free_pages * 1000ULL, requested))), info->free_blocks_total);
 664 }
 665
 666 /* Same as __fragmentation index but allocs contig_page_info on stack */
 667 int fragmentation_index(struct zone *zone, unsigned int order)
 668 {
 669         struct contig_page_info info;
 670
 671         fill_contig_page_info(zone, order, &info);
 672         return __fragmentation_index(order, &info);
 673 }
 674 #endif
 675
 676 #if defined(CONFIG_PROC_FS) || defined(CONFIG_SYSFS) || defined(CONFIG_NUMA)
 677 #ifdef CONFIG_ZONE_DMA
 678 #define TEXT_FOR_DMA(xx) xx "_dma",
 679 #else
 680 #define TEXT_FOR_DMA(xx)
 681 #endif
 682
 683 #ifdef CONFIG_ZONE_DMA32
 684 #define TEXT_FOR_DMA32(xx) xx "_dma32",
 685 #else
 686 #define TEXT_FOR_DMA32(xx)
 687 #endif
 688
 689 #ifdef CONFIG_HIGHMEM
 690 #define TEXT_FOR_HIGHMEM(xx) xx "_high",
 691 #else
 692 #define TEXT_FOR_HIGHMEM(xx)
 693 #endif
 694
 695 #define TEXTS_FOR_ZONES(xx) TEXT_FOR_DMA(xx) TEXT_FOR_DMA32(xx) xx "_normal", \
 696                                         TEXT_FOR_HIGHMEM(xx) xx "_movable",
 697
 698 const char * const vmstat_text[] = {
 699         /* enum zone_stat_item countes */
 700         "nr_free_pages",
 701         "nr_alloc_batch",
 702         "nr_inactive_anon",
 703         "nr_active_anon",
 704         "nr_inactive_file",
 705         "nr_active_file",
 706         "nr_unevictable",
 707         "nr_mlock",
 708         "nr_anon_pages",
 709         "nr_mapped",
 710         "nr_file_pages",
 711         "nr_dirty",
 712         "nr_writeback",
 713         "nr_slab_reclaimable",
 714         "nr_slab_unreclaimable",
 715         "nr_page_table_pages",
 716         "nr_kernel_stack",
 717         "nr_unstable",
 718         "nr_bounce",
 719         "nr_vmscan_write",
 720         "nr_vmscan_immediate_reclaim",
 721         "nr_writeback_temp",
 722         "nr_isolated_anon",
 723         "nr_isolated_file",
 724         "nr_shmem",
 725         "nr_dirtied",
 726         "nr_written",
 727         "nr_pages_scanned",
 728
 729 #ifdef CONFIG_NUMA
 730         "numa_hit",
 731         "numa_miss",
 732         "numa_foreign",
 733         "numa_interleave",
 734         "numa_local",
 735         "numa_other",
 736 #endif
 737         "workingset_refault",
 738         "workingset_activate",
 739         "workingset_nodereclaim",
 740         "nr_anon_transparent_hugepages",
 741         "nr_free_cma",
 742
 743         /* enum writeback_stat_item counters */
 744         "nr_dirty_threshold",
 745         "nr_dirty_background_threshold",
 746
 747 #ifdef CONFIG_VM_EVENT_COUNTERS
 748         /* enum vm_event_item counters */
 749         "pgpgin",
 750         "pgpgout",
 751         "pswpin",
 752         "pswpout",
 753
 754         TEXTS_FOR_ZONES("pgalloc")
 755
 756         "pgfree",
 757         "pgactivate",
 758         "pgdeactivate",
 759
 760         "pgfault",
 761         "pgmajfault",
 762
 763         TEXTS_FOR_ZONES("pgrefill")
 764         TEXTS_FOR_ZONES("pgsteal_kswapd")
 765         TEXTS_FOR_ZONES("pgsteal_direct")
 766         TEXTS_FOR_ZONES("pgscan_kswapd")
 767         TEXTS_FOR_ZONES("pgscan_direct")
 768         "pgscan_direct_throttle",
 769
 770 #ifdef CONFIG_NUMA
 771         "zone_reclaim_failed",
 772 #endif
 773         "pginodesteal",
 774         "slabs_scanned",
 775         "kswapd_inodesteal",
 776         "kswapd_low_wmark_hit_quickly",
 777         "kswapd_high_wmark_hit_quickly",
 778         "pageoutrun",
 779         "allocstall",
 780
 781         "pgrotated",
 782
 783         "drop_pagecache",
 784         "drop_slab",
 785
 786 #ifdef CONFIG_NUMA_BALANCING
 787         "numa_pte_updates",
 788         "numa_huge_pte_updates",
 789         "numa_hint_faults",
 790         "numa_hint_faults_local",
 791         "numa_pages_migrated",
 792 #endif
 793 #ifdef CONFIG_MIGRATION
 794         "pgmigrate_success",
 795         "pgmigrate_fail",
 796 #endif
 797 #ifdef CONFIG_COMPACTION
 798         "compact_migrate_scanned",
 799         "compact_free_scanned",
 800         "compact_isolated",
 801         "compact_stall",
 802         "compact_fail",
 803         "compact_success",
 804 #endif
 805
 806 #ifdef CONFIG_HUGETLB_PAGE
 807         "htlb_buddy_alloc_success",
 808         "htlb_buddy_alloc_fail",
 809 #endif
 810         "unevictable_pgs_culled",
 811         "unevictable_pgs_scanned",
 812         "unevictable_pgs_rescued",
 813         "unevictable_pgs_mlocked",
 814         "unevictable_pgs_munlocked",
 815         "unevictable_pgs_cleared",
 816         "unevictable_pgs_stranded",
 817
 818 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 819         "thp_fault_alloc",
 820         "thp_fault_fallback",
 821         "thp_collapse_alloc",
 822         "thp_collapse_alloc_failed",
 823         "thp_split",
 824         "thp_zero_page_alloc",
 825         "thp_zero_page_alloc_failed",
 826 #endif
 827 #ifdef CONFIG_MEMORY_BALLOON
 828         "balloon_inflate",
 829         "balloon_deflate",
 830 #ifdef CONFIG_BALLOON_COMPACTION
 831         "balloon_migrate",
 832 #endif
 833 #endif /* CONFIG_MEMORY_BALLOON */
 834 #ifdef CONFIG_DEBUG_TLBFLUSH
 835 #ifdef CONFIG_SMP
 836         "nr_tlb_remote_flush",
 837         "nr_tlb_remote_flush_received",
 838 #endif /* CONFIG_SMP */
 839         "nr_tlb_local_flush_all",
 840         "nr_tlb_local_flush_one",
 841 #endif /* CONFIG_DEBUG_TLBFLUSH */
 842
 843 #ifdef CONFIG_DEBUG_VM_VMACACHE
 844         "vmacache_find_calls",
 845         "vmacache_find_hits",
 846         "vmacache_full_flushes",
 847 #endif
 848 #endif /* CONFIG_VM_EVENTS_COUNTERS */
 849 };
 850 #endif /* CONFIG_PROC_FS || CONFIG_SYSFS || CONFIG_NUMA */
 851
 852
 853 #if (defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)) || \
 854      defined(CONFIG_PROC_FS)
 855 static void *frag_start(struct seq_file *m, loff_t *pos)
 856 {
 857         pg_data_t *pgdat;
 858         loff_t node = *pos;
 859
 860         for (pgdat = first_online_pgdat();
 861              pgdat && node;
 862              pgdat = next_online_pgdat(pgdat))
 863                 --node;
 864
 865         return pgdat;
 866 }
 867
 868 static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
 869 {
 870         pg_data_t *pgdat = (pg_data_t *)arg;
 871
 872         (*pos)++;
 873         return next_online_pgdat(pgdat);
 874 }
 875
 876 static void frag_stop(struct seq_file *m, void *arg)
 877 {
 878 }
 879
 880 /* Walk all the zones in a node and print using a callback */
 881 static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat,
 882                 void (*print)(struct seq_file *m, pg_data_t *, struct zone *))
 883 {
 884         struct zone *zone;
 885         struct zone *node_zones = pgdat->node_zones;
 886         unsigned long flags;
 887
 888         for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
 889                 if (!populated_zone(zone))
 890                         continue;
 891
 892                 spin_lock_irqsave(&zone->lock, flags);
 893                 print(m, pgdat, zone);
 894                 spin_unlock_irqrestore(&zone->lock, flags);
 895         }
 896 }
 897 #endif
 898
 899 #ifdef CONFIG_PROC_FS
 900 static char * const migratetype_names[MIGRATE_TYPES] = {
 901         "Unmovable",
 902         "Reclaimable",
 903         "Movable",
 904         "Reserve",
 905 #ifdef CONFIG_CMA
 906         "CMA",
 907 #endif
 908 #ifdef CONFIG_MEMORY_ISOLATION
 909         "Isolate",
 910 #endif
 911 };
 912
 913 static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,
 914                                                 struct zone *zone)
 915 {
 916         int order;
 917
 918         seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
 919         for (order = 0; order < MAX_ORDER; ++order)
 920                 seq_printf(m, "%6lu ", zone->free_area[order].nr_free);
 921         seq_putc(m, '\n');
 922 }
 923
 924 /*
 925  * This walks the free areas for each zone.
 926  */
 927 static int frag_show(struct seq_file *m, void *arg)
 928 {
 929         pg_data_t *pgdat = (pg_data_t *)arg;
 930         walk_zones_in_node(m, pgdat, frag_show_print);
 931         return 0;
 932 }
 933
 934 static void pagetypeinfo_showfree_print(struct seq_file *m,
 935                                         pg_data_t *pgdat, struct zone *zone)
 936 {
 937         int order, mtype;
 938
 939         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++) {
 940                 seq_printf(m, "Node %4d, zone %8s, type %12s ",
 941                                         pgdat->node_id,
 942                                         zone->name,
 943                                         migratetype_names[mtype]);
 944                 for (order = 0; order < MAX_ORDER; ++order) {
 945                         unsigned long freecount = 0;
 946                         struct free_area *area;
 947                         struct list_head *curr;
 948
 949                         area = &(zone->free_area[order]);
 950
 951                         list_for_each(curr, &area->free_list[mtype])
 952                                 freecount++;
 953                         seq_printf(m, "%6lu ", freecount);
 954                 }
 955                 seq_putc(m, '\n');
 956         }
 957 }
 958
 959 /* Print out the free pages at each order for each migatetype */
 960 static int pagetypeinfo_showfree(struct seq_file *m, void *arg)
 961 {
 962         int order;
 963         pg_data_t *pgdat = (pg_data_t *)arg;
 964
 965         /* Print header */
 966         seq_printf(m, "%-43s ", "Free pages count per migrate type at order");
 967         for (order = 0; order < MAX_ORDER; ++order)
 968                 seq_printf(m, "%6d ", order);
 969         seq_putc(m, '\n');
 970
 971         walk_zones_in_node(m, pgdat, pagetypeinfo_showfree_print);
 972
 973         return 0;
 974 }
 975
 976 static void pagetypeinfo_showblockcount_print(struct seq_file *m,
 977                                         pg_data_t *pgdat, struct zone *zone)
 978 {
 979         int mtype;
 980         unsigned long pfn;
 981         unsigned long start_pfn = zone->zone_start_pfn;
 982         unsigned long end_pfn = zone_end_pfn(zone);
 983         unsigned long count[MIGRATE_TYPES] = { 0, };
 984
 985         for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
 986                 struct page *page;
 987
 988                 if (!pfn_valid(pfn))
 989                         continue;
 990
 991                 page = pfn_to_page(pfn);
 992
 993                 /* Watch for unexpected holes punched in the memmap */
 994                 if (!memmap_valid_within(pfn, page, zone))
 995                         continue;
 996
 997                 mtype = get_pageblock_migratetype(page);
 998
 999                 if (mtype < MIGRATE_TYPES)
1000                         count[mtype]++;
1001         }
1002
1003         /* Print counts */
1004         seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
1005         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
1006                 seq_printf(m, "%12lu ", count[mtype]);
1007         seq_putc(m, '\n');
1008 }
1009
1010 /* Print out the free pages at each order for each migratetype */
1011 static int pagetypeinfo_showblockcount(struct seq_file *m, void *arg)
1012 {
1013         int mtype;
1014         pg_data_t *pgdat = (pg_data_t *)arg;
1015
1016         seq_printf(m, "\n%-23s", "Number of blocks type ");
1017         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
1018                 seq_printf(m, "%12s ", migratetype_names[mtype]);
1019         seq_putc(m, '\n');
1020         walk_zones_in_node(m, pgdat, pagetypeinfo_showblockcount_print);
1021
1022         return 0;
1023 }
1024
1025 #ifdef CONFIG_PAGE_OWNER
1026 static void pagetypeinfo_showmixedcount_print(struct seq_file *m,
1027                                                         pg_data_t *pgdat,
1028                                                         struct zone *zone)
1029 {
1030         struct page *page;
1031         struct page_ext *page_ext;
1032         unsigned long pfn = zone->zone_start_pfn, block_end_pfn;
1033         unsigned long end_pfn = pfn + zone->spanned_pages;
1034         unsigned long count[MIGRATE_TYPES] = { 0, };
1035         int pageblock_mt, page_mt;
1036         int i;
1037
1038         /* Scan block by block. First and last block may be incomplete */
1039         pfn = zone->zone_start_pfn;
1040
1041         /*
1042          * Walk the zone in pageblock_nr_pages steps. If a page block spans
1043          * a zone boundary, it will be double counted between zones. This does
1044          * not matter as the mixed block count will still be correct
1045          */
1046         for (; pfn < end_pfn; ) {
1047                 if (!pfn_valid(pfn)) {
1048                         pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
1049                         continue;
1050                 }
1051
1052                 block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages);
1053                 block_end_pfn = min(block_end_pfn, end_pfn);
1054
1055                 page = pfn_to_page(pfn);
1056                 pageblock_mt = get_pfnblock_migratetype(page, pfn);
1057
1058                 for (; pfn < block_end_pfn; pfn++) {
1059                         if (!pfn_valid_within(pfn))
1060                                 continue;
1061
1062                         page = pfn_to_page(pfn);
1063                         if (PageBuddy(page)) {
1064                                 pfn += (1UL << page_order(page)) - 1;
1065                                 continue;
1066                         }
1067
1068                         if (PageReserved(page))
1069                                 continue;
1070
1071                         page_ext = lookup_page_ext(page);
1072
1073                         if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags))
1074                                 continue;
1075
1076                         page_mt = gfpflags_to_migratetype(page_ext->gfp_mask);
1077                         if (pageblock_mt != page_mt) {
1078                                 if (is_migrate_cma(pageblock_mt))
1079                                         count[MIGRATE_MOVABLE]++;
1080                                 else
1081                                         count[pageblock_mt]++;
1082
1083                                 pfn = block_end_pfn;
1084                                 break;
1085                         }
1086                         pfn += (1UL << page_ext->order) - 1;
1087                 }
1088         }
1089
1090         /* Print counts */
1091         seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
1092         for (i = 0; i < MIGRATE_TYPES; i++)
1093                 seq_printf(m, "%12lu ", count[i]);
1094         seq_putc(m, '\n');
1095 }
1096 #endif /* CONFIG_PAGE_OWNER */
1097
1098 /*
1099  * Print out the number of pageblocks for each migratetype that contain pages
1100  * of other types. This gives an indication of how well fallbacks are being
1101  * contained by rmqueue_fallback(). It requires information from PAGE_OWNER
1102  * to determine what is going on
1103  */
1104 static void pagetypeinfo_showmixedcount(struct seq_file *m, pg_data_t *pgdat)
1105 {
1106 #ifdef CONFIG_PAGE_OWNER
1107         int mtype;
1108
1109         if (!page_owner_inited)
1110                 return;
1111
1112         drain_all_pages(NULL);
1113
1114         seq_printf(m, "\n%-23s", "Number of mixed blocks ");
1115         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
1116                 seq_printf(m, "%12s ", migratetype_names[mtype]);
1117         seq_putc(m, '\n');
1118
1119         walk_zones_in_node(m, pgdat, pagetypeinfo_showmixedcount_print);
1120 #endif /* CONFIG_PAGE_OWNER */
1121 }
1122
1123 /*
1124  * This prints out statistics in relation to grouping pages by mobility.
1125  * It is expensive to collect so do not constantly read the file.
1126  */
1127 static int pagetypeinfo_show(struct seq_file *m, void *arg)
1128 {
1129         pg_data_t *pgdat = (pg_data_t *)arg;
1130
1131         /* check memoryless node */
1132         if (!node_state(pgdat->node_id, N_MEMORY))
1133                 return 0;
1134
1135         seq_printf(m, "Page block order: %d\n", pageblock_order);
1136         seq_printf(m, "Pages per block:  %lu\n", pageblock_nr_pages);
1137         seq_putc(m, '\n');
1138         pagetypeinfo_showfree(m, pgdat);
1139         pagetypeinfo_showblockcount(m, pgdat);
1140         pagetypeinfo_showmixedcount(m, pgdat);
1141
1142         return 0;
1143 }
1144
1145 static const struct seq_operations fragmentation_op = {
1146         .start  = frag_start,
1147         .next   = frag_next,
1148         .stop   = frag_stop,
1149         .show   = frag_show,
1150 };
1151
1152 static int fragmentation_open(struct inode *inode, struct file *file)
1153 {
1154         return seq_open(file, &fragmentation_op);
1155 }
1156
1157 static const struct file_operations fragmentation_file_operations = {
1158         .open           = fragmentation_open,
1159         .read           = seq_read,
1160         .llseek         = seq_lseek,
1161         .release        = seq_release,
1162 };
1163
1164 static const struct seq_operations pagetypeinfo_op = {
1165         .start  = frag_start,
1166         .next   = frag_next,
1167         .stop   = frag_stop,
1168         .show   = pagetypeinfo_show,
1169 };
1170
1171 static int pagetypeinfo_open(struct inode *inode, struct file *file)
1172 {
1173         return seq_open(file, &pagetypeinfo_op);
1174 }
1175
1176 static const struct file_operations pagetypeinfo_file_ops = {
1177         .open           = pagetypeinfo_open,
1178         .read           = seq_read,
1179         .llseek         = seq_lseek,
1180         .release        = seq_release,
1181 };
1182
1183 static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
1184                                                         struct zone *zone)
1185 {
1186         int i;
1187         seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name);
1188         seq_printf(m,
1189                    "\n  pages free     %lu"
1190                    "\n        min      %lu"
1191                    "\n        low      %lu"
1192                    "\n        high     %lu"
1193                    "\n        scanned  %lu"
1194                    "\n        spanned  %lu"
1195                    "\n        present  %lu"
1196                    "\n        managed  %lu",
1197                    zone_page_state(zone, NR_FREE_PAGES),
1198                    min_wmark_pages(zone),
1199                    low_wmark_pages(zone),
1200                    high_wmark_pages(zone),
1201                    zone_page_state(zone, NR_PAGES_SCANNED),
1202                    zone->spanned_pages,
1203                    zone->present_pages,
1204                    zone->managed_pages);
1205
1206         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
1207                 seq_printf(m, "\n    %-12s %lu", vmstat_text[i],
1208                                 zone_page_state(zone, i));
1209
1210         seq_printf(m,
1211                    "\n        protection: (%ld",
1212                    zone->lowmem_reserve[0]);
1213         for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++)
1214                 seq_printf(m, ", %ld", zone->lowmem_reserve[i]);
1215         seq_printf(m,
1216                    ")"
1217                    "\n  pagesets");
1218         for_each_online_cpu(i) {
1219                 struct per_cpu_pageset *pageset;
1220
1221                 pageset = per_cpu_ptr(zone->pageset, i);
1222                 seq_printf(m,
1223                            "\n    cpu: %i"
1224                            "\n              count: %i"
1225                            "\n              high:  %i"
1226                            "\n              batch: %i",
1227                            i,
1228                            pageset->pcp.count,
1229                            pageset->pcp.high,
1230                            pageset->pcp.batch);
1231 #ifdef CONFIG_SMP
1232                 seq_printf(m, "\n  vm stats threshold: %d",
1233                                 pageset->stat_threshold);
1234 #endif
1235         }
1236         seq_printf(m,
1237                    "\n  all_unreclaimable: %u"
1238                    "\n  start_pfn:         %lu"
1239                    "\n  inactive_ratio:    %u",
1240                    !zone_reclaimable(zone),
1241                    zone->zone_start_pfn,
1242                    zone->inactive_ratio);
1243         seq_putc(m, '\n');
1244 }
1245
1246 /*
1247  * Output information about zones in @pgdat.
1248  */
1249 static int zoneinfo_show(struct seq_file *m, void *arg)
1250 {
1251         pg_data_t *pgdat = (pg_data_t *)arg;
1252         walk_zones_in_node(m, pgdat, zoneinfo_show_print);
1253         return 0;
1254 }
1255
1256 static const struct seq_operations zoneinfo_op = {
1257         .start  = frag_start, /* iterate over all zones. The same as in
1258                                * fragmentation. */
1259         .next   = frag_next,
1260         .stop   = frag_stop,
1261         .show   = zoneinfo_show,
1262 };
1263
1264 static int zoneinfo_open(struct inode *inode, struct file *file)
1265 {
1266         return seq_open(file, &zoneinfo_op);
1267 }
1268
1269 static const struct file_operations proc_zoneinfo_file_operations = {
1270         .open           = zoneinfo_open,
1271         .read           = seq_read,
1272         .llseek         = seq_lseek,
1273         .release        = seq_release,
1274 };
1275
1276 enum writeback_stat_item {
1277         NR_DIRTY_THRESHOLD,
1278         NR_DIRTY_BG_THRESHOLD,
1279         NR_VM_WRITEBACK_STAT_ITEMS,
1280 };
1281
1282 static void *vmstat_start(struct seq_file *m, loff_t *pos)
1283 {
1284         unsigned long *v;
1285         int i, stat_items_size;
1286
1287         if (*pos >= ARRAY_SIZE(vmstat_text))
1288                 return NULL;
1289         stat_items_size = NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long) +
1290                           NR_VM_WRITEBACK_STAT_ITEMS * sizeof(unsigned long);
1291
1292 #ifdef CONFIG_VM_EVENT_COUNTERS
1293         stat_items_size += sizeof(struct vm_event_state);
1294 #endif
1295
1296         v = kmalloc(stat_items_size, GFP_KERNEL);
1297         m->private = v;
1298         if (!v)
1299                 return ERR_PTR(-ENOMEM);
1300         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
1301                 v[i] = global_page_state(i);
1302         v += NR_VM_ZONE_STAT_ITEMS;
1303
1304         global_dirty_limits(v + NR_DIRTY_BG_THRESHOLD,
1305                             v + NR_DIRTY_THRESHOLD);
1306         v += NR_VM_WRITEBACK_STAT_ITEMS;
1307
1308 #ifdef CONFIG_VM_EVENT_COUNTERS
1309         all_vm_events(v);
1310         v[PGPGIN] /= 2;         /* sectors -> kbytes */
1311         v[PGPGOUT] /= 2;
1312 #endif
1313         return (unsigned long *)m->private + *pos;
1314 }
1315
1316 static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)
1317 {
1318         (*pos)++;
1319         if (*pos >= ARRAY_SIZE(vmstat_text))
1320                 return NULL;
1321         return (unsigned long *)m->private + *pos;
1322 }
1323
1324 static int vmstat_show(struct seq_file *m, void *arg)
1325 {
1326         unsigned long *l = arg;
1327         unsigned long off = l - (unsigned long *)m->private;
1328
1329         seq_printf(m, "%s %lu\n", vmstat_text[off], *l);
1330         return 0;
1331 }
1332
1333 static void vmstat_stop(struct seq_file *m, void *arg)
1334 {
1335         kfree(m->private);
1336         m->private = NULL;
1337 }
1338
1339 static const struct seq_operations vmstat_op = {
1340         .start  = vmstat_start,
1341         .next   = vmstat_next,
1342         .stop   = vmstat_stop,
1343         .show   = vmstat_show,
1344 };
1345
1346 static int vmstat_open(struct inode *inode, struct file *file)
1347 {
1348         return seq_open(file, &vmstat_op);
1349 }
1350
1351 static const struct file_operations proc_vmstat_file_operations = {
1352         .open           = vmstat_open,
1353         .read           = seq_read,
1354         .llseek         = seq_lseek,
1355         .release        = seq_release,
1356 };
1357 #endif /* CONFIG_PROC_FS */
1358
1359 #ifdef CONFIG_SMP
1360 static DEFINE_PER_CPU(struct delayed_work, vmstat_work);
1361 int sysctl_stat_interval __read_mostly = HZ;
1362 static cpumask_var_t cpu_stat_off;
1363
1364 static void vmstat_update(struct work_struct *w)
1365 {
1366         if (refresh_cpu_vm_stats()) {
1367                 /*
1368                  * Counters were updated so we expect more updates
1369                  * to occur in the future. Keep on running the
1370                  * update worker thread.
1371                  */
1372                 schedule_delayed_work_on(smp_processor_id(),
1373                         this_cpu_ptr(&vmstat_work),
1374                         round_jiffies_relative(sysctl_stat_interval));
1375         } else {
1376                 /*
1377                  * We did not update any counters so the app may be in
1378                  * a mode where it does not cause counter updates.
1379                  * We may be uselessly running vmstat_update.
1380                  * Defer the checking for differentials to the
1381                  * shepherd thread on a different processor.
1382                  */
1383                 int r;
1384                 /*
1385                  * Shepherd work thread does not race since it never
1386                  * changes the bit if its zero but the cpu
1387                  * online / off line code may race if
1388                  * worker threads are still allowed during
1389                  * shutdown / startup.
1390                  */
1391                 r = cpumask_test_and_set_cpu(smp_processor_id(),
1392                         cpu_stat_off);
1393                 VM_BUG_ON(r);
1394         }
1395 }
1396
1397 /*
1398  * Check if the diffs for a certain cpu indicate that
1399  * an update is needed.
1400  */
1401 static bool need_update(int cpu)
1402 {
1403         struct zone *zone;
1404
1405         for_each_populated_zone(zone) {
1406                 struct per_cpu_pageset *p = per_cpu_ptr(zone->pageset, cpu);
1407
1408                 BUILD_BUG_ON(sizeof(p->vm_stat_diff[0]) != 1);
1409                 /*
1410                  * The fast way of checking if there are any vmstat diffs.
1411                  * This works because the diffs are byte sized items.
1412                  */
1413                 if (memchr_inv(p->vm_stat_diff, 0, NR_VM_ZONE_STAT_ITEMS))
1414                         return true;
1415
1416         }
1417         return false;
1418 }
1419
1420
1421 /*
1422  * Shepherd worker thread that checks the
1423  * differentials of processors that have their worker
1424  * threads for vm statistics updates disabled because of
1425  * inactivity.
1426  */
1427 static void vmstat_shepherd(struct work_struct *w);
1428
1429 static DECLARE_DELAYED_WORK(shepherd, vmstat_shepherd);
1430
1431 static void vmstat_shepherd(struct work_struct *w)
1432 {
1433         int cpu;
1434
1435         get_online_cpus();
1436         /* Check processors whose vmstat worker threads have been disabled */
1437         for_each_cpu(cpu, cpu_stat_off)
1438                 if (need_update(cpu) &&
1439                         cpumask_test_and_clear_cpu(cpu, cpu_stat_off))
1440
1441                         schedule_delayed_work_on(cpu,
1442                                 &per_cpu(vmstat_work, cpu), 0);
1443
1444         put_online_cpus();
1445
1446         schedule_delayed_work(&shepherd,
1447                 round_jiffies_relative(sysctl_stat_interval));
1448
1449 }
1450
1451 static void __init start_shepherd_timer(void)
1452 {
1453         int cpu;
1454
1455         for_each_possible_cpu(cpu)
1456                 INIT_DELAYED_WORK(per_cpu_ptr(&vmstat_work, cpu),
1457                         vmstat_update);
1458
1459         if (!alloc_cpumask_var(&cpu_stat_off, GFP_KERNEL))
1460                 BUG();
1461         cpumask_copy(cpu_stat_off, cpu_online_mask);
1462
1463         schedule_delayed_work(&shepherd,
1464                 round_jiffies_relative(sysctl_stat_interval));
1465 }
1466
1467 static void vmstat_cpu_dead(int node)
1468 {
1469         int cpu;
1470
1471         get_online_cpus();
1472         for_each_online_cpu(cpu)
1473                 if (cpu_to_node(cpu) == node)
1474                         goto end;
1475
1476         node_clear_state(node, N_CPU);
1477 end:
1478         put_online_cpus();
1479 }
1480
1481 /*
1482  * Use the cpu notifier to insure that the thresholds are recalculated
1483  * when necessary.
1484  */
1485 static int vmstat_cpuup_callback(struct notifier_block *nfb,
1486                 unsigned long action,
1487                 void *hcpu)
1488 {
1489         long cpu = (long)hcpu;
1490
1491         switch (action) {
1492         case CPU_ONLINE:
1493         case CPU_ONLINE_FROZEN:
1494                 refresh_zone_stat_thresholds();
1495                 node_set_state(cpu_to_node(cpu), N_CPU);
1496                 cpumask_set_cpu(cpu, cpu_stat_off);
1497                 break;
1498         case CPU_DOWN_PREPARE:
1499         case CPU_DOWN_PREPARE_FROZEN:
1500                 cancel_delayed_work_sync(&per_cpu(vmstat_work, cpu));
1501                 cpumask_clear_cpu(cpu, cpu_stat_off);
1502                 break;
1503         case CPU_DOWN_FAILED:
1504         case CPU_DOWN_FAILED_FROZEN:
1505                 cpumask_set_cpu(cpu, cpu_stat_off);
1506                 break;
1507         case CPU_DEAD:
1508         case CPU_DEAD_FROZEN:
1509                 refresh_zone_stat_thresholds();
1510                 vmstat_cpu_dead(cpu_to_node(cpu));
1511                 break;
1512         default:
1513                 break;
1514         }
1515         return NOTIFY_OK;
1516 }
1517
1518 static struct notifier_block vmstat_notifier =
1519         { &vmstat_cpuup_callback, NULL, 0 };
1520 #endif
1521
1522 static int __init setup_vmstat(void)
1523 {
1524 #ifdef CONFIG_SMP
1525         cpu_notifier_register_begin();
1526         __register_cpu_notifier(&vmstat_notifier);
1527
1528         start_shepherd_timer();
1529         cpu_notifier_register_done();
1530 #endif
1531 #ifdef CONFIG_PROC_FS
1532         proc_create("buddyinfo", S_IRUGO, NULL, &fragmentation_file_operations);
1533         proc_create("pagetypeinfo", S_IRUGO, NULL, &pagetypeinfo_file_ops);
1534         proc_create("vmstat", S_IRUGO, NULL, &proc_vmstat_file_operations);
1535         proc_create("zoneinfo", S_IRUGO, NULL, &proc_zoneinfo_file_operations);
1536 #endif
1537         return 0;
1538 }
1539 module_init(setup_vmstat)
1540
1541 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)
1542
1543 /*
1544  * Return an index indicating how much of the available free memory is
1545  * unusable for an allocation of the requested size.
1546  */
1547 static int unusable_free_index(unsigned int order,
1548                                 struct contig_page_info *info)
1549 {
1550         /* No free memory is interpreted as all free memory is unusable */
1551         if (info->free_pages == 0)
1552                 return 1000;
1553
1554         /*
1555          * Index should be a value between 0 and 1. Return a value to 3
1556          * decimal places.
1557          *
1558          * 0 => no fragmentation
1559          * 1 => high fragmentation
1560          */
1561         return div_u64((info->free_pages - (info->free_blocks_suitable << order)) * 1000ULL, info->free_pages);
1562
1563 }
1564
1565 static void unusable_show_print(struct seq_file *m,
1566                                         pg_data_t *pgdat, struct zone *zone)
1567 {
1568         unsigned int order;
1569         int index;
1570         struct contig_page_info info;
1571
1572         seq_printf(m, "Node %d, zone %8s ",
1573                                 pgdat->node_id,
1574                                 zone->name);
1575         for (order = 0; order < MAX_ORDER; ++order) {
1576                 fill_contig_page_info(zone, order, &info);
1577                 index = unusable_free_index(order, &info);
1578                 seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
1579         }
1580
1581         seq_putc(m, '\n');
1582 }
1583
1584 /*
1585  * Display unusable free space index
1586  *
1587  * The unusable free space index measures how much of the available free
1588  * memory cannot be used to satisfy an allocation of a given size and is a
1589  * value between 0 and 1. The higher the value, the more of free memory is
1590  * unusable and by implication, the worse the external fragmentation is. This
1591  * can be expressed as a percentage by multiplying by 100.
1592  */
1593 static int unusable_show(struct seq_file *m, void *arg)
1594 {
1595         pg_data_t *pgdat = (pg_data_t *)arg;
1596
1597         /* check memoryless node */
1598         if (!node_state(pgdat->node_id, N_MEMORY))
1599                 return 0;
1600
1601         walk_zones_in_node(m, pgdat, unusable_show_print);
1602
1603         return 0;
1604 }
1605
1606 static const struct seq_operations unusable_op = {
1607         .start  = frag_start,
1608         .next   = frag_next,
1609         .stop   = frag_stop,
1610         .show   = unusable_show,
1611 };
1612
1613 static int unusable_open(struct inode *inode, struct file *file)
1614 {
1615         return seq_open(file, &unusable_op);
1616 }
1617
1618 static const struct file_operations unusable_file_ops = {
1619         .open           = unusable_open,
1620         .read           = seq_read,
1621         .llseek         = seq_lseek,
1622         .release        = seq_release,
1623 };
1624
1625 static void extfrag_show_print(struct seq_file *m,
1626                                         pg_data_t *pgdat, struct zone *zone)
1627 {
1628         unsigned int order;
1629         int index;
1630
1631         /* Alloc on stack as interrupts are disabled for zone walk */
1632         struct contig_page_info info;
1633
1634         seq_printf(m, "Node %d, zone %8s ",
1635                                 pgdat->node_id,
1636                                 zone->name);
1637         for (order = 0; order < MAX_ORDER; ++order) {
1638                 fill_contig_page_info(zone, order, &info);
1639                 index = __fragmentation_index(order, &info);
1640                 seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
1641         }
1642
1643         seq_putc(m, '\n');
1644 }
1645
1646 /*
1647  * Display fragmentation index for orders that allocations would fail for
1648  */
1649 static int extfrag_show(struct seq_file *m, void *arg)
1650 {
1651         pg_data_t *pgdat = (pg_data_t *)arg;
1652
1653         walk_zones_in_node(m, pgdat, extfrag_show_print);
1654
1655         return 0;
1656 }
1657
1658 static const struct seq_operations extfrag_op = {
1659         .start  = frag_start,
1660         .next   = frag_next,
1661         .stop   = frag_stop,
1662         .show   = extfrag_show,
1663 };
1664
1665 static int extfrag_open(struct inode *inode, struct file *file)
1666 {
1667         return seq_open(file, &extfrag_op);
1668 }
1669
1670 static const struct file_operations extfrag_file_ops = {
1671         .open           = extfrag_open,
1672         .read           = seq_read,
1673         .llseek         = seq_lseek,
1674         .release        = seq_release,
1675 };
1676
1677 static int __init extfrag_debug_init(void)
1678 {
1679         struct dentry *extfrag_debug_root;
1680
1681         extfrag_debug_root = debugfs_create_dir("extfrag", NULL);
1682         if (!extfrag_debug_root)
1683                 return -ENOMEM;
1684
1685         if (!debugfs_create_file("unusable_index", 0444,
1686                         extfrag_debug_root, NULL, &unusable_file_ops))
1687                 goto fail;
1688
1689         if (!debugfs_create_file("extfrag_index", 0444,
1690                         extfrag_debug_root, NULL, &extfrag_file_ops))
1691                 goto fail;
1692
1693         return 0;
1694 fail:
1695         debugfs_remove_recursive(extfrag_debug_root);
1696         return -ENOMEM;
1697 }
1698
1699 module_init(extfrag_debug_init);
1700 #endif