mm/vmstat.c

   1 /*
   2  *  linux/mm/vmstat.c
   3  *
   4  *  Manages VM statistics
   5  *  Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
   6  *
   7  *  zoned VM statistics
   8  *  Copyright (C) 2006 Silicon Graphics, Inc.,
   9  *              Christoph Lameter <christoph@lameter.com>
  10  */
  11 #include <linux/fs.h>
  12 #include <linux/mm.h>
  13 #include <linux/err.h>
  14 #include <linux/module.h>
  15 #include <linux/slab.h>
  16 #include <linux/cpu.h>
  17 #include <linux/vmstat.h>
  18 #include <linux/sched.h>
  19 #include <linux/math64.h>
  20 #include <linux/writeback.h>
  21 #include <linux/compaction.h>
  22
  23 #ifdef CONFIG_VM_EVENT_COUNTERS
  24 DEFINE_PER_CPU(struct vm_event_state, vm_event_states) = {{0}};
  25 EXPORT_PER_CPU_SYMBOL(vm_event_states);
  26
  27 static void sum_vm_events(unsigned long *ret)
  28 {
  29         int cpu;
  30         int i;
  31
  32         memset(ret, 0, NR_VM_EVENT_ITEMS * sizeof(unsigned long));
  33
  34         for_each_online_cpu(cpu) {
  35                 struct vm_event_state *this = &per_cpu(vm_event_states, cpu);
  36
  37                 for (i = 0; i < NR_VM_EVENT_ITEMS; i++)
  38                         ret[i] += this->event[i];
  39         }
  40 }
  41
  42 /*
  43  * Accumulate the vm event counters across all CPUs.
  44  * The result is unavoidably approximate - it can change
  45  * during and after execution of this function.
  46 */
  47 void all_vm_events(unsigned long *ret)
  48 {
  49         get_online_cpus();
  50         sum_vm_events(ret);
  51         put_online_cpus();
  52 }
  53 EXPORT_SYMBOL_GPL(all_vm_events);
  54
  55 #ifdef CONFIG_HOTPLUG
  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 #endif /* CONFIG_HOTPLUG */
  73
  74 #endif /* CONFIG_VM_EVENT_COUNTERS */
  75
  76 /*
  77  * Manage combined zone based / global counters
  78  *
  79  * vm_stat contains the global counters
  80  */
  81 atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS];
  82 EXPORT_SYMBOL(vm_stat);
  83
  84 #ifdef CONFIG_SMP
  85
  86 static int calculate_threshold(struct zone *zone)
  87 {
  88         int threshold;
  89         int mem;        /* memory in 128 MB units */
  90
  91         /*
  92          * The threshold scales with the number of processors and the amount
  93          * of memory per zone. More memory means that we can defer updates for
  94          * longer, more processors could lead to more contention.
  95          * fls() is used to have a cheap way of logarithmic scaling.
  96          *
  97          * Some sample thresholds:
  98          *
  99          * Threshold    Processors      (fls)   Zonesize        fls(mem+1)
 100          * ------------------------------------------------------------------
 101          * 8            1               1       0.9-1 GB        4
 102          * 16           2               2       0.9-1 GB        4
 103          * 20           2               2       1-2 GB          5
 104          * 24           2               2       2-4 GB          6
 105          * 28           2               2       4-8 GB          7
 106          * 32           2               2       8-16 GB         8
 107          * 4            2               2       <128M           1
 108          * 30           4               3       2-4 GB          5
 109          * 48           4               3       8-16 GB         8
 110          * 32           8               4       1-2 GB          4
 111          * 32           8               4       0.9-1GB         4
 112          * 10           16              5       <128M           1
 113          * 40           16              5       900M            4
 114          * 70           64              7       2-4 GB          5
 115          * 84           64              7       4-8 GB          6
 116          * 108          512             9       4-8 GB          6
 117          * 125          1024            10      8-16 GB         8
 118          * 125          1024            10      16-32 GB        9
 119          */
 120
 121         mem = zone->present_pages >> (27 - PAGE_SHIFT);
 122
 123         threshold = 2 * fls(num_online_cpus()) * (1 + fls(mem));
 124
 125         /*
 126          * Maximum threshold is 125
 127          */
 128         threshold = min(125, threshold);
 129
 130         return threshold;
 131 }
 132
 133 /*
 134  * Refresh the thresholds for each zone.
 135  */
 136 static void refresh_zone_stat_thresholds(void)
 137 {
 138         struct zone *zone;
 139         int cpu;
 140         int threshold;
 141
 142         for_each_populated_zone(zone) {
 143                 unsigned long max_drift, tolerate_drift;
 144
 145                 threshold = calculate_threshold(zone);
 146
 147                 for_each_online_cpu(cpu)
 148                         per_cpu_ptr(zone->pageset, cpu)->stat_threshold
 149                                                         = threshold;
 150
 151                 /*
 152                  * Only set percpu_drift_mark if there is a danger that
 153                  * NR_FREE_PAGES reports the low watermark is ok when in fact
 154                  * the min watermark could be breached by an allocation
 155                  */
 156                 tolerate_drift = low_wmark_pages(zone) - min_wmark_pages(zone);
 157                 max_drift = num_online_cpus() * threshold;
 158                 if (max_drift > tolerate_drift)
 159                         zone->percpu_drift_mark = high_wmark_pages(zone) +
 160                                         max_drift;
 161         }
 162 }
 163
 164 /*
 165  * For use when we know that interrupts are disabled.
 166  */
 167 void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 168                                 int delta)
 169 {
 170         struct per_cpu_pageset *pcp = this_cpu_ptr(zone->pageset);
 171
 172         s8 *p = pcp->vm_stat_diff + item;
 173         long x;
 174
 175         x = delta + *p;
 176
 177         if (unlikely(x > pcp->stat_threshold || x < -pcp->stat_threshold)) {
 178                 zone_page_state_add(x, zone, item);
 179                 x = 0;
 180         }
 181         *p = x;
 182 }
 183 EXPORT_SYMBOL(__mod_zone_page_state);
 184
 185 /*
 186  * For an unknown interrupt state
 187  */
 188 void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 189                                         int delta)
 190 {
 191         unsigned long flags;
 192
 193         local_irq_save(flags);
 194         __mod_zone_page_state(zone, item, delta);
 195         local_irq_restore(flags);
 196 }
 197 EXPORT_SYMBOL(mod_zone_page_state);
 198
 199 /*
 200  * Optimized increment and decrement functions.
 201  *
 202  * These are only for a single page and therefore can take a struct page *
 203  * argument instead of struct zone *. This allows the inclusion of the code
 204  * generated for page_zone(page) into the optimized functions.
 205  *
 206  * No overflow check is necessary and therefore the differential can be
 207  * incremented or decremented in place which may allow the compilers to
 208  * generate better code.
 209  * The increment or decrement is known and therefore one boundary check can
 210  * be omitted.
 211  *
 212  * NOTE: These functions are very performance sensitive. Change only
 213  * with care.
 214  *
 215  * Some processors have inc/dec instructions that are atomic vs an interrupt.
 216  * However, the code must first determine the differential location in a zone
 217  * based on the processor number and then inc/dec the counter. There is no
 218  * guarantee without disabling preemption that the processor will not change
 219  * in between and therefore the atomicity vs. interrupt cannot be exploited
 220  * in a useful way here.
 221  */
 222 void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
 223 {
 224         struct per_cpu_pageset *pcp = this_cpu_ptr(zone->pageset);
 225         s8 *p = pcp->vm_stat_diff + item;
 226
 227         (*p)++;
 228
 229         if (unlikely(*p > pcp->stat_threshold)) {
 230                 int overstep = pcp->stat_threshold / 2;
 231
 232                 zone_page_state_add(*p + overstep, zone, item);
 233                 *p = -overstep;
 234         }
 235 }
 236
 237 void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
 238 {
 239         __inc_zone_state(page_zone(page), item);
 240 }
 241 EXPORT_SYMBOL(__inc_zone_page_state);
 242
 243 void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
 244 {
 245         struct per_cpu_pageset *pcp = this_cpu_ptr(zone->pageset);
 246         s8 *p = pcp->vm_stat_diff + item;
 247
 248         (*p)--;
 249
 250         if (unlikely(*p < - pcp->stat_threshold)) {
 251                 int overstep = pcp->stat_threshold / 2;
 252
 253                 zone_page_state_add(*p - overstep, zone, item);
 254                 *p = overstep;
 255         }
 256 }
 257
 258 void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
 259 {
 260         __dec_zone_state(page_zone(page), item);
 261 }
 262 EXPORT_SYMBOL(__dec_zone_page_state);
 263
 264 void inc_zone_state(struct zone *zone, enum zone_stat_item item)
 265 {
 266         unsigned long flags;
 267
 268         local_irq_save(flags);
 269         __inc_zone_state(zone, item);
 270         local_irq_restore(flags);
 271 }
 272
 273 void inc_zone_page_state(struct page *page, enum zone_stat_item item)
 274 {
 275         unsigned long flags;
 276         struct zone *zone;
 277
 278         zone = page_zone(page);
 279         local_irq_save(flags);
 280         __inc_zone_state(zone, item);
 281         local_irq_restore(flags);
 282 }
 283 EXPORT_SYMBOL(inc_zone_page_state);
 284
 285 void dec_zone_page_state(struct page *page, enum zone_stat_item item)
 286 {
 287         unsigned long flags;
 288
 289         local_irq_save(flags);
 290         __dec_zone_page_state(page, item);
 291         local_irq_restore(flags);
 292 }
 293 EXPORT_SYMBOL(dec_zone_page_state);
 294
 295 /*
 296  * Update the zone counters for one cpu.
 297  *
 298  * The cpu specified must be either the current cpu or a processor that
 299  * is not online. If it is the current cpu then the execution thread must
 300  * be pinned to the current cpu.
 301  *
 302  * Note that refresh_cpu_vm_stats strives to only access
 303  * node local memory. The per cpu pagesets on remote zones are placed
 304  * in the memory local to the processor using that pageset. So the
 305  * loop over all zones will access a series of cachelines local to
 306  * the processor.
 307  *
 308  * The call to zone_page_state_add updates the cachelines with the
 309  * statistics in the remote zone struct as well as the global cachelines
 310  * with the global counters. These could cause remote node cache line
 311  * bouncing and will have to be only done when necessary.
 312  */
 313 void refresh_cpu_vm_stats(int cpu)
 314 {
 315         struct zone *zone;
 316         int i;
 317         int global_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
 318
 319         for_each_populated_zone(zone) {
 320                 struct per_cpu_pageset *p;
 321
 322                 p = per_cpu_ptr(zone->pageset, cpu);
 323
 324                 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 325                         if (p->vm_stat_diff[i]) {
 326                                 unsigned long flags;
 327                                 int v;
 328
 329                                 local_irq_save(flags);
 330                                 v = p->vm_stat_diff[i];
 331                                 p->vm_stat_diff[i] = 0;
 332                                 local_irq_restore(flags);
 333                                 atomic_long_add(v, &zone->vm_stat[i]);
 334                                 global_diff[i] += v;
 335 #ifdef CONFIG_NUMA
 336                                 /* 3 seconds idle till flush */
 337                                 p->expire = 3;
 338 #endif
 339                         }
 340                 cond_resched();
 341 #ifdef CONFIG_NUMA
 342                 /*
 343                  * Deal with draining the remote pageset of this
 344                  * processor
 345                  *
 346                  * Check if there are pages remaining in this pageset
 347                  * if not then there is nothing to expire.
 348                  */
 349                 if (!p->expire || !p->pcp.count)
 350                         continue;
 351
 352                 /*
 353                  * We never drain zones local to this processor.
 354                  */
 355                 if (zone_to_nid(zone) == numa_node_id()) {
 356                         p->expire = 0;
 357                         continue;
 358                 }
 359
 360                 p->expire--;
 361                 if (p->expire)
 362                         continue;
 363
 364                 if (p->pcp.count)
 365                         drain_zone_pages(zone, &p->pcp);
 366 #endif
 367         }
 368
 369         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 370                 if (global_diff[i])
 371                         atomic_long_add(global_diff[i], &vm_stat[i]);
 372 }
 373
 374 #endif
 375
 376 #ifdef CONFIG_NUMA
 377 /*
 378  * zonelist = the list of zones passed to the allocator
 379  * z        = the zone from which the allocation occurred.
 380  *
 381  * Must be called with interrupts disabled.
 382  */
 383 void zone_statistics(struct zone *preferred_zone, struct zone *z)
 384 {
 385         if (z->zone_pgdat == preferred_zone->zone_pgdat) {
 386                 __inc_zone_state(z, NUMA_HIT);
 387         } else {
 388                 __inc_zone_state(z, NUMA_MISS);
 389                 __inc_zone_state(preferred_zone, NUMA_FOREIGN);
 390         }
 391         if (z->node == numa_node_id())
 392                 __inc_zone_state(z, NUMA_LOCAL);
 393         else
 394                 __inc_zone_state(z, NUMA_OTHER);
 395 }
 396 #endif
 397
 398 #ifdef CONFIG_COMPACTION
 399
 400 struct contig_page_info {
 401         unsigned long free_pages;
 402         unsigned long free_blocks_total;
 403         unsigned long free_blocks_suitable;
 404 };
 405
 406 /*
 407  * Calculate the number of free pages in a zone, how many contiguous
 408  * pages are free and how many are large enough to satisfy an allocation of
 409  * the target size. Note that this function makes no attempt to estimate
 410  * how many suitable free blocks there *might* be if MOVABLE pages were
 411  * migrated. Calculating that is possible, but expensive and can be
 412  * figured out from userspace
 413  */
 414 static void fill_contig_page_info(struct zone *zone,
 415                                 unsigned int suitable_order,
 416                                 struct contig_page_info *info)
 417 {
 418         unsigned int order;
 419
 420         info->free_pages = 0;
 421         info->free_blocks_total = 0;
 422         info->free_blocks_suitable = 0;
 423
 424         for (order = 0; order < MAX_ORDER; order++) {
 425                 unsigned long blocks;
 426
 427                 /* Count number of free blocks */
 428                 blocks = zone->free_area[order].nr_free;
 429                 info->free_blocks_total += blocks;
 430
 431                 /* Count free base pages */
 432                 info->free_pages += blocks << order;
 433
 434                 /* Count the suitable free blocks */
 435                 if (order >= suitable_order)
 436                         info->free_blocks_suitable += blocks <<
 437                                                 (order - suitable_order);
 438         }
 439 }
 440
 441 /*
 442  * A fragmentation index only makes sense if an allocation of a requested
 443  * size would fail. If that is true, the fragmentation index indicates
 444  * whether external fragmentation or a lack of memory was the problem.
 445  * The value can be used to determine if page reclaim or compaction
 446  * should be used
 447  */
 448 static int __fragmentation_index(unsigned int order, struct contig_page_info *info)
 449 {
 450         unsigned long requested = 1UL << order;
 451
 452         if (!info->free_blocks_total)
 453                 return 0;
 454
 455         /* Fragmentation index only makes sense when a request would fail */
 456         if (info->free_blocks_suitable)
 457                 return -1000;
 458
 459         /*
 460          * Index is between 0 and 1 so return within 3 decimal places
 461          *
 462          * 0 => allocation would fail due to lack of memory
 463          * 1 => allocation would fail due to fragmentation
 464          */
 465         return 1000 - div_u64( (1000+(div_u64(info->free_pages * 1000ULL, requested))), info->free_blocks_total);
 466 }
 467
 468 /* Same as __fragmentation index but allocs contig_page_info on stack */
 469 int fragmentation_index(struct zone *zone, unsigned int order)
 470 {
 471         struct contig_page_info info;
 472
 473         fill_contig_page_info(zone, order, &info);
 474         return __fragmentation_index(order, &info);
 475 }
 476 #endif
 477
 478 #if defined(CONFIG_PROC_FS) || defined(CONFIG_COMPACTION)
 479 #include <linux/proc_fs.h>
 480 #include <linux/seq_file.h>
 481
 482 static char * const migratetype_names[MIGRATE_TYPES] = {
 483         "Unmovable",
 484         "Reclaimable",
 485         "Movable",
 486         "Reserve",
 487         "Isolate",
 488 };
 489
 490 static void *frag_start(struct seq_file *m, loff_t *pos)
 491 {
 492         pg_data_t *pgdat;
 493         loff_t node = *pos;
 494         for (pgdat = first_online_pgdat();
 495              pgdat && node;
 496              pgdat = next_online_pgdat(pgdat))
 497                 --node;
 498
 499         return pgdat;
 500 }
 501
 502 static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
 503 {
 504         pg_data_t *pgdat = (pg_data_t *)arg;
 505
 506         (*pos)++;
 507         return next_online_pgdat(pgdat);
 508 }
 509
 510 static void frag_stop(struct seq_file *m, void *arg)
 511 {
 512 }
 513
 514 /* Walk all the zones in a node and print using a callback */
 515 static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat,
 516                 void (*print)(struct seq_file *m, pg_data_t *, struct zone *))
 517 {
 518         struct zone *zone;
 519         struct zone *node_zones = pgdat->node_zones;
 520         unsigned long flags;
 521
 522         for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
 523                 if (!populated_zone(zone))
 524                         continue;
 525
 526                 spin_lock_irqsave(&zone->lock, flags);
 527                 print(m, pgdat, zone);
 528                 spin_unlock_irqrestore(&zone->lock, flags);
 529         }
 530 }
 531 #endif
 532
 533 #ifdef CONFIG_PROC_FS
 534 static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,
 535                                                 struct zone *zone)
 536 {
 537         int order;
 538
 539         seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
 540         for (order = 0; order < MAX_ORDER; ++order)
 541                 seq_printf(m, "%6lu ", zone->free_area[order].nr_free);
 542         seq_putc(m, '\n');
 543 }
 544
 545 /*
 546  * This walks the free areas for each zone.
 547  */
 548 static int frag_show(struct seq_file *m, void *arg)
 549 {
 550         pg_data_t *pgdat = (pg_data_t *)arg;
 551         walk_zones_in_node(m, pgdat, frag_show_print);
 552         return 0;
 553 }
 554
 555 static void pagetypeinfo_showfree_print(struct seq_file *m,
 556                                         pg_data_t *pgdat, struct zone *zone)
 557 {
 558         int order, mtype;
 559
 560         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++) {
 561                 seq_printf(m, "Node %4d, zone %8s, type %12s ",
 562                                         pgdat->node_id,
 563                                         zone->name,
 564                                         migratetype_names[mtype]);
 565                 for (order = 0; order < MAX_ORDER; ++order) {
 566                         unsigned long freecount = 0;
 567                         struct free_area *area;
 568                         struct list_head *curr;
 569
 570                         area = &(zone->free_area[order]);
 571
 572                         list_for_each(curr, &area->free_list[mtype])
 573                                 freecount++;
 574                         seq_printf(m, "%6lu ", freecount);
 575                 }
 576                 seq_putc(m, '\n');
 577         }
 578 }
 579
 580 /* Print out the free pages at each order for each migatetype */
 581 static int pagetypeinfo_showfree(struct seq_file *m, void *arg)
 582 {
 583         int order;
 584         pg_data_t *pgdat = (pg_data_t *)arg;
 585
 586         /* Print header */
 587         seq_printf(m, "%-43s ", "Free pages count per migrate type at order");
 588         for (order = 0; order < MAX_ORDER; ++order)
 589                 seq_printf(m, "%6d ", order);
 590         seq_putc(m, '\n');
 591
 592         walk_zones_in_node(m, pgdat, pagetypeinfo_showfree_print);
 593
 594         return 0;
 595 }
 596
 597 static void pagetypeinfo_showblockcount_print(struct seq_file *m,
 598                                         pg_data_t *pgdat, struct zone *zone)
 599 {
 600         int mtype;
 601         unsigned long pfn;
 602         unsigned long start_pfn = zone->zone_start_pfn;
 603         unsigned long end_pfn = start_pfn + zone->spanned_pages;
 604         unsigned long count[MIGRATE_TYPES] = { 0, };
 605
 606         for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
 607                 struct page *page;
 608
 609                 if (!pfn_valid(pfn))
 610                         continue;
 611
 612                 page = pfn_to_page(pfn);
 613
 614                 /* Watch for unexpected holes punched in the memmap */
 615                 if (!memmap_valid_within(pfn, page, zone))
 616                         continue;
 617
 618                 mtype = get_pageblock_migratetype(page);
 619
 620                 if (mtype < MIGRATE_TYPES)
 621                         count[mtype]++;
 622         }
 623
 624         /* Print counts */
 625         seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
 626         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
 627                 seq_printf(m, "%12lu ", count[mtype]);
 628         seq_putc(m, '\n');
 629 }
 630
 631 /* Print out the free pages at each order for each migratetype */
 632 static int pagetypeinfo_showblockcount(struct seq_file *m, void *arg)
 633 {
 634         int mtype;
 635         pg_data_t *pgdat = (pg_data_t *)arg;
 636
 637         seq_printf(m, "\n%-23s", "Number of blocks type ");
 638         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
 639                 seq_printf(m, "%12s ", migratetype_names[mtype]);
 640         seq_putc(m, '\n');
 641         walk_zones_in_node(m, pgdat, pagetypeinfo_showblockcount_print);
 642
 643         return 0;
 644 }
 645
 646 /*
 647  * This prints out statistics in relation to grouping pages by mobility.
 648  * It is expensive to collect so do not constantly read the file.
 649  */
 650 static int pagetypeinfo_show(struct seq_file *m, void *arg)
 651 {
 652         pg_data_t *pgdat = (pg_data_t *)arg;
 653
 654         /* check memoryless node */
 655         if (!node_state(pgdat->node_id, N_HIGH_MEMORY))
 656                 return 0;
 657
 658         seq_printf(m, "Page block order: %d\n", pageblock_order);
 659         seq_printf(m, "Pages per block:  %lu\n", pageblock_nr_pages);
 660         seq_putc(m, '\n');
 661         pagetypeinfo_showfree(m, pgdat);
 662         pagetypeinfo_showblockcount(m, pgdat);
 663
 664         return 0;
 665 }
 666
 667 static const struct seq_operations fragmentation_op = {
 668         .start  = frag_start,
 669         .next   = frag_next,
 670         .stop   = frag_stop,
 671         .show   = frag_show,
 672 };
 673
 674 static int fragmentation_open(struct inode *inode, struct file *file)
 675 {
 676         return seq_open(file, &fragmentation_op);
 677 }
 678
 679 static const struct file_operations fragmentation_file_operations = {
 680         .open           = fragmentation_open,
 681         .read           = seq_read,
 682         .llseek         = seq_lseek,
 683         .release        = seq_release,
 684 };
 685
 686 static const struct seq_operations pagetypeinfo_op = {
 687         .start  = frag_start,
 688         .next   = frag_next,
 689         .stop   = frag_stop,
 690         .show   = pagetypeinfo_show,
 691 };
 692
 693 static int pagetypeinfo_open(struct inode *inode, struct file *file)
 694 {
 695         return seq_open(file, &pagetypeinfo_op);
 696 }
 697
 698 static const struct file_operations pagetypeinfo_file_ops = {
 699         .open           = pagetypeinfo_open,
 700         .read           = seq_read,
 701         .llseek         = seq_lseek,
 702         .release        = seq_release,
 703 };
 704
 705 #ifdef CONFIG_ZONE_DMA
 706 #define TEXT_FOR_DMA(xx) xx "_dma",
 707 #else
 708 #define TEXT_FOR_DMA(xx)
 709 #endif
 710
 711 #ifdef CONFIG_ZONE_DMA32
 712 #define TEXT_FOR_DMA32(xx) xx "_dma32",
 713 #else
 714 #define TEXT_FOR_DMA32(xx)
 715 #endif
 716
 717 #ifdef CONFIG_HIGHMEM
 718 #define TEXT_FOR_HIGHMEM(xx) xx "_high",
 719 #else
 720 #define TEXT_FOR_HIGHMEM(xx)
 721 #endif
 722
 723 #define TEXTS_FOR_ZONES(xx) TEXT_FOR_DMA(xx) TEXT_FOR_DMA32(xx) xx "_normal", \
 724                                         TEXT_FOR_HIGHMEM(xx) xx "_movable",
 725
 726 static const char * const vmstat_text[] = {
 727         /* Zoned VM counters */
 728         "nr_free_pages",
 729         "nr_inactive_anon",
 730         "nr_active_anon",
 731         "nr_inactive_file",
 732         "nr_active_file",
 733         "nr_unevictable",
 734         "nr_mlock",
 735         "nr_anon_pages",
 736         "nr_mapped",
 737         "nr_file_pages",
 738         "nr_dirty",
 739         "nr_writeback",
 740         "nr_slab_reclaimable",
 741         "nr_slab_unreclaimable",
 742         "nr_page_table_pages",
 743         "nr_kernel_stack",
 744         "nr_unstable",
 745         "nr_bounce",
 746         "nr_vmscan_write",
 747         "nr_writeback_temp",
 748         "nr_isolated_anon",
 749         "nr_isolated_file",
 750         "nr_shmem",
 751         "nr_dirtied",
 752         "nr_written",
 753         "nr_dirty_threshold",
 754         "nr_dirty_background_threshold",
 755
 756 #ifdef CONFIG_NUMA
 757         "numa_hit",
 758         "numa_miss",
 759         "numa_foreign",
 760         "numa_interleave",
 761         "numa_local",
 762         "numa_other",
 763 #endif
 764
 765 #ifdef CONFIG_VM_EVENT_COUNTERS
 766         "pgpgin",
 767         "pgpgout",
 768         "pswpin",
 769         "pswpout",
 770
 771         TEXTS_FOR_ZONES("pgalloc")
 772
 773         "pgfree",
 774         "pgactivate",
 775         "pgdeactivate",
 776
 777         "pgfault",
 778         "pgmajfault",
 779
 780         TEXTS_FOR_ZONES("pgrefill")
 781         TEXTS_FOR_ZONES("pgsteal")
 782         TEXTS_FOR_ZONES("pgscan_kswapd")
 783         TEXTS_FOR_ZONES("pgscan_direct")
 784
 785 #ifdef CONFIG_NUMA
 786         "zone_reclaim_failed",
 787 #endif
 788         "pginodesteal",
 789         "slabs_scanned",
 790         "kswapd_steal",
 791         "kswapd_inodesteal",
 792         "kswapd_low_wmark_hit_quickly",
 793         "kswapd_high_wmark_hit_quickly",
 794         "kswapd_skip_congestion_wait",
 795         "pageoutrun",
 796         "allocstall",
 797
 798         "pgrotated",
 799
 800 #ifdef CONFIG_COMPACTION
 801         "compact_blocks_moved",
 802         "compact_pages_moved",
 803         "compact_pagemigrate_failed",
 804         "compact_stall",
 805         "compact_fail",
 806         "compact_success",
 807 #endif
 808
 809 #ifdef CONFIG_HUGETLB_PAGE
 810         "htlb_buddy_alloc_success",
 811         "htlb_buddy_alloc_fail",
 812 #endif
 813         "unevictable_pgs_culled",
 814         "unevictable_pgs_scanned",
 815         "unevictable_pgs_rescued",
 816         "unevictable_pgs_mlocked",
 817         "unevictable_pgs_munlocked",
 818         "unevictable_pgs_cleared",
 819         "unevictable_pgs_stranded",
 820         "unevictable_pgs_mlockfreed",
 821 #endif
 822 };
 823
 824 static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
 825                                                         struct zone *zone)
 826 {
 827         int i;
 828         seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name);
 829         seq_printf(m,
 830                    "\n  pages free     %lu"
 831                    "\n        min      %lu"
 832                    "\n        low      %lu"
 833                    "\n        high     %lu"
 834                    "\n        scanned  %lu"
 835                    "\n        spanned  %lu"
 836                    "\n        present  %lu",
 837                    zone_nr_free_pages(zone),
 838                    min_wmark_pages(zone),
 839                    low_wmark_pages(zone),
 840                    high_wmark_pages(zone),
 841                    zone->pages_scanned,
 842                    zone->spanned_pages,
 843                    zone->present_pages);
 844
 845         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 846                 seq_printf(m, "\n    %-12s %lu", vmstat_text[i],
 847                                 zone_page_state(zone, i));
 848
 849         seq_printf(m,
 850                    "\n        protection: (%lu",
 851                    zone->lowmem_reserve[0]);
 852         for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++)
 853                 seq_printf(m, ", %lu", zone->lowmem_reserve[i]);
 854         seq_printf(m,
 855                    ")"
 856                    "\n  pagesets");
 857         for_each_online_cpu(i) {
 858                 struct per_cpu_pageset *pageset;
 859
 860                 pageset = per_cpu_ptr(zone->pageset, i);
 861                 seq_printf(m,
 862                            "\n    cpu: %i"
 863                            "\n              count: %i"
 864                            "\n              high:  %i"
 865                            "\n              batch: %i",
 866                            i,
 867                            pageset->pcp.count,
 868                            pageset->pcp.high,
 869                            pageset->pcp.batch);
 870 #ifdef CONFIG_SMP
 871                 seq_printf(m, "\n  vm stats threshold: %d",
 872                                 pageset->stat_threshold);
 873 #endif
 874         }
 875         seq_printf(m,
 876                    "\n  all_unreclaimable: %u"
 877                    "\n  start_pfn:         %lu"
 878                    "\n  inactive_ratio:    %u",
 879                    zone->all_unreclaimable,
 880                    zone->zone_start_pfn,
 881                    zone->inactive_ratio);
 882         seq_putc(m, '\n');
 883 }
 884
 885 /*
 886  * Output information about zones in @pgdat.
 887  */
 888 static int zoneinfo_show(struct seq_file *m, void *arg)
 889 {
 890         pg_data_t *pgdat = (pg_data_t *)arg;
 891         walk_zones_in_node(m, pgdat, zoneinfo_show_print);
 892         return 0;
 893 }
 894
 895 static const struct seq_operations zoneinfo_op = {
 896         .start  = frag_start, /* iterate over all zones. The same as in
 897                                * fragmentation. */
 898         .next   = frag_next,
 899         .stop   = frag_stop,
 900         .show   = zoneinfo_show,
 901 };
 902
 903 static int zoneinfo_open(struct inode *inode, struct file *file)
 904 {
 905         return seq_open(file, &zoneinfo_op);
 906 }
 907
 908 static const struct file_operations proc_zoneinfo_file_operations = {
 909         .open           = zoneinfo_open,
 910         .read           = seq_read,
 911         .llseek         = seq_lseek,
 912         .release        = seq_release,
 913 };
 914
 915 enum writeback_stat_item {
 916         NR_DIRTY_THRESHOLD,
 917         NR_DIRTY_BG_THRESHOLD,
 918         NR_VM_WRITEBACK_STAT_ITEMS,
 919 };
 920
 921 static void *vmstat_start(struct seq_file *m, loff_t *pos)
 922 {
 923         unsigned long *v;
 924         int i, stat_items_size;
 925
 926         if (*pos >= ARRAY_SIZE(vmstat_text))
 927                 return NULL;
 928         stat_items_size = NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long) +
 929                           NR_VM_WRITEBACK_STAT_ITEMS * sizeof(unsigned long);
 930
 931 #ifdef CONFIG_VM_EVENT_COUNTERS
 932         stat_items_size += sizeof(struct vm_event_state);
 933 #endif
 934
 935         v = kmalloc(stat_items_size, GFP_KERNEL);
 936         m->private = v;
 937         if (!v)
 938                 return ERR_PTR(-ENOMEM);
 939         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 940                 v[i] = global_page_state(i);
 941         v += NR_VM_ZONE_STAT_ITEMS;
 942
 943         global_dirty_limits(v + NR_DIRTY_BG_THRESHOLD,
 944                             v + NR_DIRTY_THRESHOLD);
 945         v += NR_VM_WRITEBACK_STAT_ITEMS;
 946
 947 #ifdef CONFIG_VM_EVENT_COUNTERS
 948         all_vm_events(v);
 949         v[PGPGIN] /= 2;         /* sectors -> kbytes */
 950         v[PGPGOUT] /= 2;
 951 #endif
 952         return m->private + *pos;
 953 }
 954
 955 static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)
 956 {
 957         (*pos)++;
 958         if (*pos >= ARRAY_SIZE(vmstat_text))
 959                 return NULL;
 960         return (unsigned long *)m->private + *pos;
 961 }
 962
 963 static int vmstat_show(struct seq_file *m, void *arg)
 964 {
 965         unsigned long *l = arg;
 966         unsigned long off = l - (unsigned long *)m->private;
 967
 968         seq_printf(m, "%s %lu\n", vmstat_text[off], *l);
 969         return 0;
 970 }
 971
 972 static void vmstat_stop(struct seq_file *m, void *arg)
 973 {
 974         kfree(m->private);
 975         m->private = NULL;
 976 }
 977
 978 static const struct seq_operations vmstat_op = {
 979         .start  = vmstat_start,
 980         .next   = vmstat_next,
 981         .stop   = vmstat_stop,
 982         .show   = vmstat_show,
 983 };
 984
 985 static int vmstat_open(struct inode *inode, struct file *file)
 986 {
 987         return seq_open(file, &vmstat_op);
 988 }
 989
 990 static const struct file_operations proc_vmstat_file_operations = {
 991         .open           = vmstat_open,
 992         .read           = seq_read,
 993         .llseek         = seq_lseek,
 994         .release        = seq_release,
 995 };
 996 #endif /* CONFIG_PROC_FS */
 997
 998 #ifdef CONFIG_SMP
 999 static DEFINE_PER_CPU(struct delayed_work, vmstat_work);
1000 int sysctl_stat_interval __read_mostly = HZ;
1001
1002 static void vmstat_update(struct work_struct *w)
1003 {
1004         refresh_cpu_vm_stats(smp_processor_id());
1005         schedule_delayed_work(&__get_cpu_var(vmstat_work),
1006                 round_jiffies_relative(sysctl_stat_interval));
1007 }
1008
1009 static void __cpuinit start_cpu_timer(int cpu)
1010 {
1011         struct delayed_work *work = &per_cpu(vmstat_work, cpu);
1012
1013         INIT_DELAYED_WORK_DEFERRABLE(work, vmstat_update);
1014         schedule_delayed_work_on(cpu, work, __round_jiffies_relative(HZ, cpu));
1015 }
1016
1017 /*
1018  * Use the cpu notifier to insure that the thresholds are recalculated
1019  * when necessary.
1020  */
1021 static int __cpuinit vmstat_cpuup_callback(struct notifier_block *nfb,
1022                 unsigned long action,
1023                 void *hcpu)
1024 {
1025         long cpu = (long)hcpu;
1026
1027         switch (action) {
1028         case CPU_ONLINE:
1029         case CPU_ONLINE_FROZEN:
1030                 refresh_zone_stat_thresholds();
1031                 start_cpu_timer(cpu);
1032                 node_set_state(cpu_to_node(cpu), N_CPU);
1033                 break;
1034         case CPU_DOWN_PREPARE:
1035         case CPU_DOWN_PREPARE_FROZEN:
1036                 cancel_rearming_delayed_work(&per_cpu(vmstat_work, cpu));
1037                 per_cpu(vmstat_work, cpu).work.func = NULL;
1038                 break;
1039         case CPU_DOWN_FAILED:
1040         case CPU_DOWN_FAILED_FROZEN:
1041                 start_cpu_timer(cpu);
1042                 break;
1043         case CPU_DEAD:
1044         case CPU_DEAD_FROZEN:
1045                 refresh_zone_stat_thresholds();
1046                 break;
1047         default:
1048                 break;
1049         }
1050         return NOTIFY_OK;
1051 }
1052
1053 static struct notifier_block __cpuinitdata vmstat_notifier =
1054         { &vmstat_cpuup_callback, NULL, 0 };
1055 #endif
1056
1057 static int __init setup_vmstat(void)
1058 {
1059 #ifdef CONFIG_SMP
1060         int cpu;
1061
1062         refresh_zone_stat_thresholds();
1063         register_cpu_notifier(&vmstat_notifier);
1064
1065         for_each_online_cpu(cpu)
1066                 start_cpu_timer(cpu);
1067 #endif
1068 #ifdef CONFIG_PROC_FS
1069         proc_create("buddyinfo", S_IRUGO, NULL, &fragmentation_file_operations);
1070         proc_create("pagetypeinfo", S_IRUGO, NULL, &pagetypeinfo_file_ops);
1071         proc_create("vmstat", S_IRUGO, NULL, &proc_vmstat_file_operations);
1072         proc_create("zoneinfo", S_IRUGO, NULL, &proc_zoneinfo_file_operations);
1073 #endif
1074         return 0;
1075 }
1076 module_init(setup_vmstat)
1077
1078 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)
1079 #include <linux/debugfs.h>
1080
1081 static struct dentry *extfrag_debug_root;
1082
1083 /*
1084  * Return an index indicating how much of the available free memory is
1085  * unusable for an allocation of the requested size.
1086  */
1087 static int unusable_free_index(unsigned int order,
1088                                 struct contig_page_info *info)
1089 {
1090         /* No free memory is interpreted as all free memory is unusable */
1091         if (info->free_pages == 0)
1092                 return 1000;
1093
1094         /*
1095          * Index should be a value between 0 and 1. Return a value to 3
1096          * decimal places.
1097          *
1098          * 0 => no fragmentation
1099          * 1 => high fragmentation
1100          */
1101         return div_u64((info->free_pages - (info->free_blocks_suitable << order)) * 1000ULL, info->free_pages);
1102
1103 }
1104
1105 static void unusable_show_print(struct seq_file *m,
1106                                         pg_data_t *pgdat, struct zone *zone)
1107 {
1108         unsigned int order;
1109         int index;
1110         struct contig_page_info info;
1111
1112         seq_printf(m, "Node %d, zone %8s ",
1113                                 pgdat->node_id,
1114                                 zone->name);
1115         for (order = 0; order < MAX_ORDER; ++order) {
1116                 fill_contig_page_info(zone, order, &info);
1117                 index = unusable_free_index(order, &info);
1118                 seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
1119         }
1120
1121         seq_putc(m, '\n');
1122 }
1123
1124 /*
1125  * Display unusable free space index
1126  *
1127  * The unusable free space index measures how much of the available free
1128  * memory cannot be used to satisfy an allocation of a given size and is a
1129  * value between 0 and 1. The higher the value, the more of free memory is
1130  * unusable and by implication, the worse the external fragmentation is. This
1131  * can be expressed as a percentage by multiplying by 100.
1132  */
1133 static int unusable_show(struct seq_file *m, void *arg)
1134 {
1135         pg_data_t *pgdat = (pg_data_t *)arg;
1136
1137         /* check memoryless node */
1138         if (!node_state(pgdat->node_id, N_HIGH_MEMORY))
1139                 return 0;
1140
1141         walk_zones_in_node(m, pgdat, unusable_show_print);
1142
1143         return 0;
1144 }
1145
1146 static const struct seq_operations unusable_op = {
1147         .start  = frag_start,
1148         .next   = frag_next,
1149         .stop   = frag_stop,
1150         .show   = unusable_show,
1151 };
1152
1153 static int unusable_open(struct inode *inode, struct file *file)
1154 {
1155         return seq_open(file, &unusable_op);
1156 }
1157
1158 static const struct file_operations unusable_file_ops = {
1159         .open           = unusable_open,
1160         .read           = seq_read,
1161         .llseek         = seq_lseek,
1162         .release        = seq_release,
1163 };
1164
1165 static void extfrag_show_print(struct seq_file *m,
1166                                         pg_data_t *pgdat, struct zone *zone)
1167 {
1168         unsigned int order;
1169         int index;
1170
1171         /* Alloc on stack as interrupts are disabled for zone walk */
1172         struct contig_page_info info;
1173
1174         seq_printf(m, "Node %d, zone %8s ",
1175                                 pgdat->node_id,
1176                                 zone->name);
1177         for (order = 0; order < MAX_ORDER; ++order) {
1178                 fill_contig_page_info(zone, order, &info);
1179                 index = __fragmentation_index(order, &info);
1180                 seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
1181         }
1182
1183         seq_putc(m, '\n');
1184 }
1185
1186 /*
1187  * Display fragmentation index for orders that allocations would fail for
1188  */
1189 static int extfrag_show(struct seq_file *m, void *arg)
1190 {
1191         pg_data_t *pgdat = (pg_data_t *)arg;
1192
1193         walk_zones_in_node(m, pgdat, extfrag_show_print);
1194
1195         return 0;
1196 }
1197
1198 static const struct seq_operations extfrag_op = {
1199         .start  = frag_start,
1200         .next   = frag_next,
1201         .stop   = frag_stop,
1202         .show   = extfrag_show,
1203 };
1204
1205 static int extfrag_open(struct inode *inode, struct file *file)
1206 {
1207         return seq_open(file, &extfrag_op);
1208 }
1209
1210 static const struct file_operations extfrag_file_ops = {
1211         .open           = extfrag_open,
1212         .read           = seq_read,
1213         .llseek         = seq_lseek,
1214         .release        = seq_release,
1215 };
1216
1217 static int __init extfrag_debug_init(void)
1218 {
1219         extfrag_debug_root = debugfs_create_dir("extfrag", NULL);
1220         if (!extfrag_debug_root)
1221                 return -ENOMEM;
1222
1223         if (!debugfs_create_file("unusable_index", 0444,
1224                         extfrag_debug_root, NULL, &unusable_file_ops))
1225                 return -ENOMEM;
1226
1227         if (!debugfs_create_file("extfrag_index", 0444,
1228                         extfrag_debug_root, NULL, &extfrag_file_ops))
1229                 return -ENOMEM;
1230
1231         return 0;
1232 }
1233
1234 module_init(extfrag_debug_init);
1235 #endif