err.no Git - linux-2.6/blob - mm/vmstat.c

   1 /*
   2  *  linux/mm/vmstat.c
   3  *
   4  *  Manages VM statistics
   5  *  Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
   6  *
   7  *  zoned VM statistics
   8  *  Copyright (C) 2006 Silicon Graphics, Inc.,
   9  *              Christoph Lameter <christoph@lameter.com>
  10  */
  11
  12 #include <linux/mm.h>
  13 #include <linux/err.h>
  14 #include <linux/module.h>
  15 #include <linux/cpu.h>
  16 #include <linux/sched.h>
  17
  18 #ifdef CONFIG_VM_EVENT_COUNTERS
  19 DEFINE_PER_CPU(struct vm_event_state, vm_event_states) = {{0}};
  20 EXPORT_PER_CPU_SYMBOL(vm_event_states);
  21
  22 static void sum_vm_events(unsigned long *ret, cpumask_t *cpumask)
  23 {
  24         int cpu;
  25         int i;
  26
  27         memset(ret, 0, NR_VM_EVENT_ITEMS * sizeof(unsigned long));
  28
  29         for_each_cpu_mask(cpu, *cpumask) {
  30                 struct vm_event_state *this = &per_cpu(vm_event_states, cpu);
  31
  32                 for (i = 0; i < NR_VM_EVENT_ITEMS; i++)
  33                         ret[i] += this->event[i];
  34         }
  35 }
  36
  37 /*
  38  * Accumulate the vm event counters across all CPUs.
  39  * The result is unavoidably approximate - it can change
  40  * during and after execution of this function.
  41 */
  42 void all_vm_events(unsigned long *ret)
  43 {
  44         get_online_cpus();
  45         sum_vm_events(ret, &cpu_online_map);
  46         put_online_cpus();
  47 }
  48 EXPORT_SYMBOL_GPL(all_vm_events);
  49
  50 #ifdef CONFIG_HOTPLUG
  51 /*
  52  * Fold the foreign cpu events into our own.
  53  *
  54  * This is adding to the events on one processor
  55  * but keeps the global counts constant.
  56  */
  57 void vm_events_fold_cpu(int cpu)
  58 {
  59         struct vm_event_state *fold_state = &per_cpu(vm_event_states, cpu);
  60         int i;
  61
  62         for (i = 0; i < NR_VM_EVENT_ITEMS; i++) {
  63                 count_vm_events(i, fold_state->event[i]);
  64                 fold_state->event[i] = 0;
  65         }
  66 }
  67 #endif /* CONFIG_HOTPLUG */
  68
  69 #endif /* CONFIG_VM_EVENT_COUNTERS */
  70
  71 /*
  72  * Manage combined zone based / global counters
  73  *
  74  * vm_stat contains the global counters
  75  */
  76 atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS];
  77 EXPORT_SYMBOL(vm_stat);
  78
  79 #ifdef CONFIG_SMP
  80
  81 static int calculate_threshold(struct zone *zone)
  82 {
  83         int threshold;
  84         int mem;        /* memory in 128 MB units */
  85
  86         /*
  87          * The threshold scales with the number of processors and the amount
  88          * of memory per zone. More memory means that we can defer updates for
  89          * longer, more processors could lead to more contention.
  90          * fls() is used to have a cheap way of logarithmic scaling.
  91          *
  92          * Some sample thresholds:
  93          *
  94          * Threshold    Processors      (fls)   Zonesize        fls(mem+1)
  95          * ------------------------------------------------------------------
  96          * 8            1               1       0.9-1 GB        4
  97          * 16           2               2       0.9-1 GB        4
  98          * 20           2               2       1-2 GB          5
  99          * 24           2               2       2-4 GB          6
 100          * 28           2               2       4-8 GB          7
 101          * 32           2               2       8-16 GB         8
 102          * 4            2               2       <128M           1
 103          * 30           4               3       2-4 GB          5
 104          * 48           4               3       8-16 GB         8
 105          * 32           8               4       1-2 GB          4
 106          * 32           8               4       0.9-1GB         4
 107          * 10           16              5       <128M           1
 108          * 40           16              5       900M            4
 109          * 70           64              7       2-4 GB          5
 110          * 84           64              7       4-8 GB          6
 111          * 108          512             9       4-8 GB          6
 112          * 125          1024            10      8-16 GB         8
 113          * 125          1024            10      16-32 GB        9
 114          */
 115
 116         mem = zone->present_pages >> (27 - PAGE_SHIFT);
 117
 118         threshold = 2 * fls(num_online_cpus()) * (1 + fls(mem));
 119
 120         /*
 121          * Maximum threshold is 125
 122          */
 123         threshold = min(125, threshold);
 124
 125         return threshold;
 126 }
 127
 128 /*
 129  * Refresh the thresholds for each zone.
 130  */
 131 static void refresh_zone_stat_thresholds(void)
 132 {
 133         struct zone *zone;
 134         int cpu;
 135         int threshold;
 136
 137         for_each_zone(zone) {
 138
 139                 if (!zone->present_pages)
 140                         continue;
 141
 142                 threshold = calculate_threshold(zone);
 143
 144                 for_each_online_cpu(cpu)
 145                         zone_pcp(zone, cpu)->stat_threshold = threshold;
 146         }
 147 }
 148
 149 /*
 150  * For use when we know that interrupts are disabled.
 151  */
 152 void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 153                                 int delta)
 154 {
 155         struct per_cpu_pageset *pcp = zone_pcp(zone, smp_processor_id());
 156         s8 *p = pcp->vm_stat_diff + item;
 157         long x;
 158
 159         x = delta + *p;
 160
 161         if (unlikely(x > pcp->stat_threshold || x < -pcp->stat_threshold)) {
 162                 zone_page_state_add(x, zone, item);
 163                 x = 0;
 164         }
 165         *p = x;
 166 }
 167 EXPORT_SYMBOL(__mod_zone_page_state);
 168
 169 /*
 170  * For an unknown interrupt state
 171  */
 172 void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 173                                         int delta)
 174 {
 175         unsigned long flags;
 176
 177         local_irq_save(flags);
 178         __mod_zone_page_state(zone, item, delta);
 179         local_irq_restore(flags);
 180 }
 181 EXPORT_SYMBOL(mod_zone_page_state);
 182
 183 /*
 184  * Optimized increment and decrement functions.
 185  *
 186  * These are only for a single page and therefore can take a struct page *
 187  * argument instead of struct zone *. This allows the inclusion of the code
 188  * generated for page_zone(page) into the optimized functions.
 189  *
 190  * No overflow check is necessary and therefore the differential can be
 191  * incremented or decremented in place which may allow the compilers to
 192  * generate better code.
 193  * The increment or decrement is known and therefore one boundary check can
 194  * be omitted.
 195  *
 196  * NOTE: These functions are very performance sensitive. Change only
 197  * with care.
 198  *
 199  * Some processors have inc/dec instructions that are atomic vs an interrupt.
 200  * However, the code must first determine the differential location in a zone
 201  * based on the processor number and then inc/dec the counter. There is no
 202  * guarantee without disabling preemption that the processor will not change
 203  * in between and therefore the atomicity vs. interrupt cannot be exploited
 204  * in a useful way here.
 205  */
 206 void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
 207 {
 208         struct per_cpu_pageset *pcp = zone_pcp(zone, smp_processor_id());
 209         s8 *p = pcp->vm_stat_diff + item;
 210
 211         (*p)++;
 212
 213         if (unlikely(*p > pcp->stat_threshold)) {
 214                 int overstep = pcp->stat_threshold / 2;
 215
 216                 zone_page_state_add(*p + overstep, zone, item);
 217                 *p = -overstep;
 218         }
 219 }
 220
 221 void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
 222 {
 223         __inc_zone_state(page_zone(page), item);
 224 }
 225 EXPORT_SYMBOL(__inc_zone_page_state);
 226
 227 void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
 228 {
 229         struct per_cpu_pageset *pcp = zone_pcp(zone, smp_processor_id());
 230         s8 *p = pcp->vm_stat_diff + item;
 231
 232         (*p)--;
 233
 234         if (unlikely(*p < - pcp->stat_threshold)) {
 235                 int overstep = pcp->stat_threshold / 2;
 236
 237                 zone_page_state_add(*p - overstep, zone, item);
 238                 *p = overstep;
 239         }
 240 }
 241
 242 void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
 243 {
 244         __dec_zone_state(page_zone(page), item);
 245 }
 246 EXPORT_SYMBOL(__dec_zone_page_state);
 247
 248 void inc_zone_state(struct zone *zone, enum zone_stat_item item)
 249 {
 250         unsigned long flags;
 251
 252         local_irq_save(flags);
 253         __inc_zone_state(zone, item);
 254         local_irq_restore(flags);
 255 }
 256
 257 void inc_zone_page_state(struct page *page, enum zone_stat_item item)
 258 {
 259         unsigned long flags;
 260         struct zone *zone;
 261
 262         zone = page_zone(page);
 263         local_irq_save(flags);
 264         __inc_zone_state(zone, item);
 265         local_irq_restore(flags);
 266 }
 267 EXPORT_SYMBOL(inc_zone_page_state);
 268
 269 void dec_zone_page_state(struct page *page, enum zone_stat_item item)
 270 {
 271         unsigned long flags;
 272
 273         local_irq_save(flags);
 274         __dec_zone_page_state(page, item);
 275         local_irq_restore(flags);
 276 }
 277 EXPORT_SYMBOL(dec_zone_page_state);
 278
 279 /*
 280  * Update the zone counters for one cpu.
 281  *
 282  * The cpu specified must be either the current cpu or a processor that
 283  * is not online. If it is the current cpu then the execution thread must
 284  * be pinned to the current cpu.
 285  *
 286  * Note that refresh_cpu_vm_stats strives to only access
 287  * node local memory. The per cpu pagesets on remote zones are placed
 288  * in the memory local to the processor using that pageset. So the
 289  * loop over all zones will access a series of cachelines local to
 290  * the processor.
 291  *
 292  * The call to zone_page_state_add updates the cachelines with the
 293  * statistics in the remote zone struct as well as the global cachelines
 294  * with the global counters. These could cause remote node cache line
 295  * bouncing and will have to be only done when necessary.
 296  */
 297 void refresh_cpu_vm_stats(int cpu)
 298 {
 299         struct zone *zone;
 300         int i;
 301         int global_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
 302
 303         for_each_zone(zone) {
 304                 struct per_cpu_pageset *p;
 305
 306                 if (!populated_zone(zone))
 307                         continue;
 308
 309                 p = zone_pcp(zone, cpu);
 310
 311                 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 312                         if (p->vm_stat_diff[i]) {
 313                                 unsigned long flags;
 314                                 int v;
 315
 316                                 local_irq_save(flags);
 317                                 v = p->vm_stat_diff[i];
 318                                 p->vm_stat_diff[i] = 0;
 319                                 local_irq_restore(flags);
 320                                 atomic_long_add(v, &zone->vm_stat[i]);
 321                                 global_diff[i] += v;
 322 #ifdef CONFIG_NUMA
 323                                 /* 3 seconds idle till flush */
 324                                 p->expire = 3;
 325 #endif
 326                         }
 327                 cond_resched();
 328 #ifdef CONFIG_NUMA
 329                 /*
 330                  * Deal with draining the remote pageset of this
 331                  * processor
 332                  *
 333                  * Check if there are pages remaining in this pageset
 334                  * if not then there is nothing to expire.
 335                  */
 336                 if (!p->expire || !p->pcp.count)
 337                         continue;
 338
 339                 /*
 340                  * We never drain zones local to this processor.
 341                  */
 342                 if (zone_to_nid(zone) == numa_node_id()) {
 343                         p->expire = 0;
 344                         continue;
 345                 }
 346
 347                 p->expire--;
 348                 if (p->expire)
 349                         continue;
 350
 351                 if (p->pcp.count)
 352                         drain_zone_pages(zone, &p->pcp);
 353 #endif
 354         }
 355
 356         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 357                 if (global_diff[i])
 358                         atomic_long_add(global_diff[i], &vm_stat[i]);
 359 }
 360
 361 #endif
 362
 363 #ifdef CONFIG_NUMA
 364 /*
 365  * zonelist = the list of zones passed to the allocator
 366  * z        = the zone from which the allocation occurred.
 367  *
 368  * Must be called with interrupts disabled.
 369  */
 370 void zone_statistics(struct zone *preferred_zone, struct zone *z)
 371 {
 372         if (z->zone_pgdat == preferred_zone->zone_pgdat) {
 373                 __inc_zone_state(z, NUMA_HIT);
 374         } else {
 375                 __inc_zone_state(z, NUMA_MISS);
 376                 __inc_zone_state(preferred_zone, NUMA_FOREIGN);
 377         }
 378         if (z->node == numa_node_id())
 379                 __inc_zone_state(z, NUMA_LOCAL);
 380         else
 381                 __inc_zone_state(z, NUMA_OTHER);
 382 }
 383 #endif
 384
 385 #ifdef CONFIG_PROC_FS
 386
 387 #include <linux/seq_file.h>
 388
 389 static char * const migratetype_names[MIGRATE_TYPES] = {
 390         "Unmovable",
 391         "Reclaimable",
 392         "Movable",
 393         "Reserve",
 394         "Isolate",
 395 };
 396
 397 static void *frag_start(struct seq_file *m, loff_t *pos)
 398 {
 399         pg_data_t *pgdat;
 400         loff_t node = *pos;
 401         for (pgdat = first_online_pgdat();
 402              pgdat && node;
 403              pgdat = next_online_pgdat(pgdat))
 404                 --node;
 405
 406         return pgdat;
 407 }
 408
 409 static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
 410 {
 411         pg_data_t *pgdat = (pg_data_t *)arg;
 412
 413         (*pos)++;
 414         return next_online_pgdat(pgdat);
 415 }
 416
 417 static void frag_stop(struct seq_file *m, void *arg)
 418 {
 419 }
 420
 421 /* Walk all the zones in a node and print using a callback */
 422 static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat,
 423                 void (*print)(struct seq_file *m, pg_data_t *, struct zone *))
 424 {
 425         struct zone *zone;
 426         struct zone *node_zones = pgdat->node_zones;
 427         unsigned long flags;
 428
 429         for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
 430                 if (!populated_zone(zone))
 431                         continue;
 432
 433                 spin_lock_irqsave(&zone->lock, flags);
 434                 print(m, pgdat, zone);
 435                 spin_unlock_irqrestore(&zone->lock, flags);
 436         }
 437 }
 438
 439 static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,
 440                                                 struct zone *zone)
 441 {
 442         int order;
 443
 444         seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
 445         for (order = 0; order < MAX_ORDER; ++order)
 446                 seq_printf(m, "%6lu ", zone->free_area[order].nr_free);
 447         seq_putc(m, '\n');
 448 }
 449
 450 /*
 451  * This walks the free areas for each zone.
 452  */
 453 static int frag_show(struct seq_file *m, void *arg)
 454 {
 455         pg_data_t *pgdat = (pg_data_t *)arg;
 456         walk_zones_in_node(m, pgdat, frag_show_print);
 457         return 0;
 458 }
 459
 460 static void pagetypeinfo_showfree_print(struct seq_file *m,
 461                                         pg_data_t *pgdat, struct zone *zone)
 462 {
 463         int order, mtype;
 464
 465         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++) {
 466                 seq_printf(m, "Node %4d, zone %8s, type %12s ",
 467                                         pgdat->node_id,
 468                                         zone->name,
 469                                         migratetype_names[mtype]);
 470                 for (order = 0; order < MAX_ORDER; ++order) {
 471                         unsigned long freecount = 0;
 472                         struct free_area *area;
 473                         struct list_head *curr;
 474
 475                         area = &(zone->free_area[order]);
 476
 477                         list_for_each(curr, &area->free_list[mtype])
 478                                 freecount++;
 479                         seq_printf(m, "%6lu ", freecount);
 480                 }
 481                 seq_putc(m, '\n');
 482         }
 483 }
 484
 485 /* Print out the free pages at each order for each migatetype */
 486 static int pagetypeinfo_showfree(struct seq_file *m, void *arg)
 487 {
 488         int order;
 489         pg_data_t *pgdat = (pg_data_t *)arg;
 490
 491         /* Print header */
 492         seq_printf(m, "%-43s ", "Free pages count per migrate type at order");
 493         for (order = 0; order < MAX_ORDER; ++order)
 494                 seq_printf(m, "%6d ", order);
 495         seq_putc(m, '\n');
 496
 497         walk_zones_in_node(m, pgdat, pagetypeinfo_showfree_print);
 498
 499         return 0;
 500 }
 501
 502 static void pagetypeinfo_showblockcount_print(struct seq_file *m,
 503                                         pg_data_t *pgdat, struct zone *zone)
 504 {
 505         int mtype;
 506         unsigned long pfn;
 507         unsigned long start_pfn = zone->zone_start_pfn;
 508         unsigned long end_pfn = start_pfn + zone->spanned_pages;
 509         unsigned long count[MIGRATE_TYPES] = { 0, };
 510
 511         for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
 512                 struct page *page;
 513
 514                 if (!pfn_valid(pfn))
 515                         continue;
 516
 517                 page = pfn_to_page(pfn);
 518                 mtype = get_pageblock_migratetype(page);
 519
 520                 count[mtype]++;
 521         }
 522
 523         /* Print counts */
 524         seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
 525         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
 526                 seq_printf(m, "%12lu ", count[mtype]);
 527         seq_putc(m, '\n');
 528 }
 529
 530 /* Print out the free pages at each order for each migratetype */
 531 static int pagetypeinfo_showblockcount(struct seq_file *m, void *arg)
 532 {
 533         int mtype;
 534         pg_data_t *pgdat = (pg_data_t *)arg;
 535
 536         seq_printf(m, "\n%-23s", "Number of blocks type ");
 537         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
 538                 seq_printf(m, "%12s ", migratetype_names[mtype]);
 539         seq_putc(m, '\n');
 540         walk_zones_in_node(m, pgdat, pagetypeinfo_showblockcount_print);
 541
 542         return 0;
 543 }
 544
 545 /*
 546  * This prints out statistics in relation to grouping pages by mobility.
 547  * It is expensive to collect so do not constantly read the file.
 548  */
 549 static int pagetypeinfo_show(struct seq_file *m, void *arg)
 550 {
 551         pg_data_t *pgdat = (pg_data_t *)arg;
 552
 553         /* check memoryless node */
 554         if (!node_state(pgdat->node_id, N_HIGH_MEMORY))
 555                 return 0;
 556
 557         seq_printf(m, "Page block order: %d\n", pageblock_order);
 558         seq_printf(m, "Pages per block:  %lu\n", pageblock_nr_pages);
 559         seq_putc(m, '\n');
 560         pagetypeinfo_showfree(m, pgdat);
 561         pagetypeinfo_showblockcount(m, pgdat);
 562
 563         return 0;
 564 }
 565
 566 const struct seq_operations fragmentation_op = {
 567         .start  = frag_start,
 568         .next   = frag_next,
 569         .stop   = frag_stop,
 570         .show   = frag_show,
 571 };
 572
 573 const struct seq_operations pagetypeinfo_op = {
 574         .start  = frag_start,
 575         .next   = frag_next,
 576         .stop   = frag_stop,
 577         .show   = pagetypeinfo_show,
 578 };
 579
 580 #ifdef CONFIG_ZONE_DMA
 581 #define TEXT_FOR_DMA(xx) xx "_dma",
 582 #else
 583 #define TEXT_FOR_DMA(xx)
 584 #endif
 585
 586 #ifdef CONFIG_ZONE_DMA32
 587 #define TEXT_FOR_DMA32(xx) xx "_dma32",
 588 #else
 589 #define TEXT_FOR_DMA32(xx)
 590 #endif
 591
 592 #ifdef CONFIG_HIGHMEM
 593 #define TEXT_FOR_HIGHMEM(xx) xx "_high",
 594 #else
 595 #define TEXT_FOR_HIGHMEM(xx)
 596 #endif
 597
 598 #define TEXTS_FOR_ZONES(xx) TEXT_FOR_DMA(xx) TEXT_FOR_DMA32(xx) xx "_normal", \
 599                                         TEXT_FOR_HIGHMEM(xx) xx "_movable",
 600
 601 static const char * const vmstat_text[] = {
 602         /* Zoned VM counters */
 603         "nr_free_pages",
 604         "nr_inactive",
 605         "nr_active",
 606         "nr_anon_pages",
 607         "nr_mapped",
 608         "nr_file_pages",
 609         "nr_dirty",
 610         "nr_writeback",
 611         "nr_slab_reclaimable",
 612         "nr_slab_unreclaimable",
 613         "nr_page_table_pages",
 614         "nr_unstable",
 615         "nr_bounce",
 616         "nr_vmscan_write",
 617         "nr_writeback_temp",
 618
 619 #ifdef CONFIG_NUMA
 620         "numa_hit",
 621         "numa_miss",
 622         "numa_foreign",
 623         "numa_interleave",
 624         "numa_local",
 625         "numa_other",
 626 #endif
 627
 628 #ifdef CONFIG_VM_EVENT_COUNTERS
 629         "pgpgin",
 630         "pgpgout",
 631         "pswpin",
 632         "pswpout",
 633
 634         TEXTS_FOR_ZONES("pgalloc")
 635
 636         "pgfree",
 637         "pgactivate",
 638         "pgdeactivate",
 639
 640         "pgfault",
 641         "pgmajfault",
 642
 643         TEXTS_FOR_ZONES("pgrefill")
 644         TEXTS_FOR_ZONES("pgsteal")
 645         TEXTS_FOR_ZONES("pgscan_kswapd")
 646         TEXTS_FOR_ZONES("pgscan_direct")
 647
 648         "pginodesteal",
 649         "slabs_scanned",
 650         "kswapd_steal",
 651         "kswapd_inodesteal",
 652         "pageoutrun",
 653         "allocstall",
 654
 655         "pgrotated",
 656 #ifdef CONFIG_HUGETLB_PAGE
 657         "htlb_buddy_alloc_success",
 658         "htlb_buddy_alloc_fail",
 659 #endif
 660 #endif
 661 };
 662
 663 static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
 664                                                         struct zone *zone)
 665 {
 666         int i;
 667         seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name);
 668         seq_printf(m,
 669                    "\n  pages free     %lu"
 670                    "\n        min      %lu"
 671                    "\n        low      %lu"
 672                    "\n        high     %lu"
 673                    "\n        scanned  %lu (a: %lu i: %lu)"
 674                    "\n        spanned  %lu"
 675                    "\n        present  %lu",
 676                    zone_page_state(zone, NR_FREE_PAGES),
 677                    zone->pages_min,
 678                    zone->pages_low,
 679                    zone->pages_high,
 680                    zone->pages_scanned,
 681                    zone->nr_scan_active, zone->nr_scan_inactive,
 682                    zone->spanned_pages,
 683                    zone->present_pages);
 684
 685         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 686                 seq_printf(m, "\n    %-12s %lu", vmstat_text[i],
 687                                 zone_page_state(zone, i));
 688
 689         seq_printf(m,
 690                    "\n        protection: (%lu",
 691                    zone->lowmem_reserve[0]);
 692         for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++)
 693                 seq_printf(m, ", %lu", zone->lowmem_reserve[i]);
 694         seq_printf(m,
 695                    ")"
 696                    "\n  pagesets");
 697         for_each_online_cpu(i) {
 698                 struct per_cpu_pageset *pageset;
 699
 700                 pageset = zone_pcp(zone, i);
 701                 seq_printf(m,
 702                            "\n    cpu: %i"
 703                            "\n              count: %i"
 704                            "\n              high:  %i"
 705                            "\n              batch: %i",
 706                            i,
 707                            pageset->pcp.count,
 708                            pageset->pcp.high,
 709                            pageset->pcp.batch);
 710 #ifdef CONFIG_SMP
 711                 seq_printf(m, "\n  vm stats threshold: %d",
 712                                 pageset->stat_threshold);
 713 #endif
 714         }
 715         seq_printf(m,
 716                    "\n  all_unreclaimable: %u"
 717                    "\n  prev_priority:     %i"
 718                    "\n  start_pfn:         %lu",
 719                            zone_is_all_unreclaimable(zone),
 720                    zone->prev_priority,
 721                    zone->zone_start_pfn);
 722         seq_putc(m, '\n');
 723 }
 724
 725 /*
 726  * Output information about zones in @pgdat.
 727  */
 728 static int zoneinfo_show(struct seq_file *m, void *arg)
 729 {
 730         pg_data_t *pgdat = (pg_data_t *)arg;
 731         walk_zones_in_node(m, pgdat, zoneinfo_show_print);
 732         return 0;
 733 }
 734
 735 const struct seq_operations zoneinfo_op = {
 736         .start  = frag_start, /* iterate over all zones. The same as in
 737                                * fragmentation. */
 738         .next   = frag_next,
 739         .stop   = frag_stop,
 740         .show   = zoneinfo_show,
 741 };
 742
 743 static void *vmstat_start(struct seq_file *m, loff_t *pos)
 744 {
 745         unsigned long *v;
 746 #ifdef CONFIG_VM_EVENT_COUNTERS
 747         unsigned long *e;
 748 #endif
 749         int i;
 750
 751         if (*pos >= ARRAY_SIZE(vmstat_text))
 752                 return NULL;
 753
 754 #ifdef CONFIG_VM_EVENT_COUNTERS
 755         v = kmalloc(NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long)
 756                         + sizeof(struct vm_event_state), GFP_KERNEL);
 757 #else
 758         v = kmalloc(NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long),
 759                         GFP_KERNEL);
 760 #endif
 761         m->private = v;
 762         if (!v)
 763                 return ERR_PTR(-ENOMEM);
 764         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 765                 v[i] = global_page_state(i);
 766 #ifdef CONFIG_VM_EVENT_COUNTERS
 767         e = v + NR_VM_ZONE_STAT_ITEMS;
 768         all_vm_events(e);
 769         e[PGPGIN] /= 2;         /* sectors -> kbytes */
 770         e[PGPGOUT] /= 2;
 771 #endif
 772         return v + *pos;
 773 }
 774
 775 static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)
 776 {
 777         (*pos)++;
 778         if (*pos >= ARRAY_SIZE(vmstat_text))
 779                 return NULL;
 780         return (unsigned long *)m->private + *pos;
 781 }
 782
 783 static int vmstat_show(struct seq_file *m, void *arg)
 784 {
 785         unsigned long *l = arg;
 786         unsigned long off = l - (unsigned long *)m->private;
 787
 788         seq_printf(m, "%s %lu\n", vmstat_text[off], *l);
 789         return 0;
 790 }
 791
 792 static void vmstat_stop(struct seq_file *m, void *arg)
 793 {
 794         kfree(m->private);
 795         m->private = NULL;
 796 }
 797
 798 const struct seq_operations vmstat_op = {
 799         .start  = vmstat_start,
 800         .next   = vmstat_next,
 801         .stop   = vmstat_stop,
 802         .show   = vmstat_show,
 803 };
 804
 805 #endif /* CONFIG_PROC_FS */
 806
 807 #ifdef CONFIG_SMP
 808 static DEFINE_PER_CPU(struct delayed_work, vmstat_work);
 809 int sysctl_stat_interval __read_mostly = HZ;
 810
 811 static void vmstat_update(struct work_struct *w)
 812 {
 813         refresh_cpu_vm_stats(smp_processor_id());
 814         schedule_delayed_work(&__get_cpu_var(vmstat_work),
 815                 sysctl_stat_interval);
 816 }
 817
 818 static void __cpuinit start_cpu_timer(int cpu)
 819 {
 820         struct delayed_work *vmstat_work = &per_cpu(vmstat_work, cpu);
 821
 822         INIT_DELAYED_WORK_DEFERRABLE(vmstat_work, vmstat_update);
 823         schedule_delayed_work_on(cpu, vmstat_work, HZ + cpu);
 824 }
 825
 826 /*
 827  * Use the cpu notifier to insure that the thresholds are recalculated
 828  * when necessary.
 829  */
 830 static int __cpuinit vmstat_cpuup_callback(struct notifier_block *nfb,
 831                 unsigned long action,
 832                 void *hcpu)
 833 {
 834         long cpu = (long)hcpu;
 835
 836         switch (action) {
 837         case CPU_ONLINE:
 838         case CPU_ONLINE_FROZEN:
 839                 start_cpu_timer(cpu);
 840                 break;
 841         case CPU_DOWN_PREPARE:
 842         case CPU_DOWN_PREPARE_FROZEN:
 843                 cancel_rearming_delayed_work(&per_cpu(vmstat_work, cpu));
 844                 per_cpu(vmstat_work, cpu).work.func = NULL;
 845                 break;
 846         case CPU_DOWN_FAILED:
 847         case CPU_DOWN_FAILED_FROZEN:
 848                 start_cpu_timer(cpu);
 849                 break;
 850         case CPU_DEAD:
 851         case CPU_DEAD_FROZEN:
 852                 refresh_zone_stat_thresholds();
 853                 break;
 854         default:
 855                 break;
 856         }
 857         return NOTIFY_OK;
 858 }
 859
 860 static struct notifier_block __cpuinitdata vmstat_notifier =
 861         { &vmstat_cpuup_callback, NULL, 0 };
 862
 863 static int __init setup_vmstat(void)
 864 {
 865         int cpu;
 866
 867         refresh_zone_stat_thresholds();
 868         register_cpu_notifier(&vmstat_notifier);
 869
 870         for_each_online_cpu(cpu)
 871                 start_cpu_timer(cpu);
 872         return 0;
 873 }
 874 module_init(setup_vmstat)
 875 #endif