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/config.h>
  13 #include <linux/mm.h>
  14 #include <linux/module.h>
  15
  16 /*
  17  * Accumulate the page_state information across all CPUs.
  18  * The result is unavoidably approximate - it can change
  19  * during and after execution of this function.
  20  */
  21 DEFINE_PER_CPU(struct page_state, page_states) = {0};
  22
  23 static void __get_page_state(struct page_state *ret, int nr, cpumask_t *cpumask)
  24 {
  25         unsigned cpu;
  26
  27         memset(ret, 0, nr * sizeof(unsigned long));
  28         cpus_and(*cpumask, *cpumask, cpu_online_map);
  29
  30         for_each_cpu_mask(cpu, *cpumask) {
  31                 unsigned long *in;
  32                 unsigned long *out;
  33                 unsigned off;
  34                 unsigned next_cpu;
  35
  36                 in = (unsigned long *)&per_cpu(page_states, cpu);
  37
  38                 next_cpu = next_cpu(cpu, *cpumask);
  39                 if (likely(next_cpu < NR_CPUS))
  40                         prefetch(&per_cpu(page_states, next_cpu));
  41
  42                 out = (unsigned long *)ret;
  43                 for (off = 0; off < nr; off++)
  44                         *out++ += *in++;
  45         }
  46 }
  47
  48 void get_page_state_node(struct page_state *ret, int node)
  49 {
  50         int nr;
  51         cpumask_t mask = node_to_cpumask(node);
  52
  53         nr = offsetof(struct page_state, GET_PAGE_STATE_LAST);
  54         nr /= sizeof(unsigned long);
  55
  56         __get_page_state(ret, nr+1, &mask);
  57 }
  58
  59 void get_page_state(struct page_state *ret)
  60 {
  61         int nr;
  62         cpumask_t mask = CPU_MASK_ALL;
  63
  64         nr = offsetof(struct page_state, GET_PAGE_STATE_LAST);
  65         nr /= sizeof(unsigned long);
  66
  67         __get_page_state(ret, nr + 1, &mask);
  68 }
  69
  70 void get_full_page_state(struct page_state *ret)
  71 {
  72         cpumask_t mask = CPU_MASK_ALL;
  73
  74         __get_page_state(ret, sizeof(*ret) / sizeof(unsigned long), &mask);
  75 }
  76
  77 unsigned long read_page_state_offset(unsigned long offset)
  78 {
  79         unsigned long ret = 0;
  80         int cpu;
  81
  82         for_each_online_cpu(cpu) {
  83                 unsigned long in;
  84
  85                 in = (unsigned long)&per_cpu(page_states, cpu) + offset;
  86                 ret += *((unsigned long *)in);
  87         }
  88         return ret;
  89 }
  90
  91 void __mod_page_state_offset(unsigned long offset, unsigned long delta)
  92 {
  93         void *ptr;
  94
  95         ptr = &__get_cpu_var(page_states);
  96         *(unsigned long *)(ptr + offset) += delta;
  97 }
  98 EXPORT_SYMBOL(__mod_page_state_offset);
  99
 100 void mod_page_state_offset(unsigned long offset, unsigned long delta)
 101 {
 102         unsigned long flags;
 103         void *ptr;
 104
 105         local_irq_save(flags);
 106         ptr = &__get_cpu_var(page_states);
 107         *(unsigned long *)(ptr + offset) += delta;
 108         local_irq_restore(flags);
 109 }
 110 EXPORT_SYMBOL(mod_page_state_offset);
 111
 112 void __get_zone_counts(unsigned long *active, unsigned long *inactive,
 113                         unsigned long *free, struct pglist_data *pgdat)
 114 {
 115         struct zone *zones = pgdat->node_zones;
 116         int i;
 117
 118         *active = 0;
 119         *inactive = 0;
 120         *free = 0;
 121         for (i = 0; i < MAX_NR_ZONES; i++) {
 122                 *active += zones[i].nr_active;
 123                 *inactive += zones[i].nr_inactive;
 124                 *free += zones[i].free_pages;
 125         }
 126 }
 127
 128 void get_zone_counts(unsigned long *active,
 129                 unsigned long *inactive, unsigned long *free)
 130 {
 131         struct pglist_data *pgdat;
 132
 133         *active = 0;
 134         *inactive = 0;
 135         *free = 0;
 136         for_each_online_pgdat(pgdat) {
 137                 unsigned long l, m, n;
 138                 __get_zone_counts(&l, &m, &n, pgdat);
 139                 *active += l;
 140                 *inactive += m;
 141                 *free += n;
 142         }
 143 }
 144
 145 /*
 146  * Manage combined zone based / global counters
 147  *
 148  * vm_stat contains the global counters
 149  */
 150 atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS];
 151 EXPORT_SYMBOL(vm_stat);
 152
 153 #ifdef CONFIG_SMP
 154
 155 #define STAT_THRESHOLD 32
 156
 157 /*
 158  * Determine pointer to currently valid differential byte given a zone and
 159  * the item number.
 160  *
 161  * Preemption must be off
 162  */
 163 static inline s8 *diff_pointer(struct zone *zone, enum zone_stat_item item)
 164 {
 165         return &zone_pcp(zone, smp_processor_id())->vm_stat_diff[item];
 166 }
 167
 168 /*
 169  * For use when we know that interrupts are disabled.
 170  */
 171 void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 172                                 int delta)
 173 {
 174         s8 *p;
 175         long x;
 176
 177         p = diff_pointer(zone, item);
 178         x = delta + *p;
 179
 180         if (unlikely(x > STAT_THRESHOLD || x < -STAT_THRESHOLD)) {
 181                 zone_page_state_add(x, zone, item);
 182                 x = 0;
 183         }
 184
 185         *p = x;
 186 }
 187 EXPORT_SYMBOL(__mod_zone_page_state);
 188
 189 /*
 190  * For an unknown interrupt state
 191  */
 192 void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 193                                         int delta)
 194 {
 195         unsigned long flags;
 196
 197         local_irq_save(flags);
 198         __mod_zone_page_state(zone, item, delta);
 199         local_irq_restore(flags);
 200 }
 201 EXPORT_SYMBOL(mod_zone_page_state);
 202
 203 /*
 204  * Optimized increment and decrement functions.
 205  *
 206  * These are only for a single page and therefore can take a struct page *
 207  * argument instead of struct zone *. This allows the inclusion of the code
 208  * generated for page_zone(page) into the optimized functions.
 209  *
 210  * No overflow check is necessary and therefore the differential can be
 211  * incremented or decremented in place which may allow the compilers to
 212  * generate better code.
 213  *
 214  * The increment or decrement is known and therefore one boundary check can
 215  * be omitted.
 216  *
 217  * Some processors have inc/dec instructions that are atomic vs an interrupt.
 218  * However, the code must first determine the differential location in a zone
 219  * based on the processor number and then inc/dec the counter. There is no
 220  * guarantee without disabling preemption that the processor will not change
 221  * in between and therefore the atomicity vs. interrupt cannot be exploited
 222  * in a useful way here.
 223  */
 224 void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
 225 {
 226         struct zone *zone = page_zone(page);
 227         s8 *p = diff_pointer(zone, item);
 228
 229         (*p)++;
 230
 231         if (unlikely(*p > STAT_THRESHOLD)) {
 232                 zone_page_state_add(*p, zone, item);
 233                 *p = 0;
 234         }
 235 }
 236 EXPORT_SYMBOL(__inc_zone_page_state);
 237
 238 void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
 239 {
 240         struct zone *zone = page_zone(page);
 241         s8 *p = diff_pointer(zone, item);
 242
 243         (*p)--;
 244
 245         if (unlikely(*p < -STAT_THRESHOLD)) {
 246                 zone_page_state_add(*p, zone, item);
 247                 *p = 0;
 248         }
 249 }
 250 EXPORT_SYMBOL(__dec_zone_page_state);
 251
 252 void inc_zone_page_state(struct page *page, enum zone_stat_item item)
 253 {
 254         unsigned long flags;
 255         struct zone *zone;
 256         s8 *p;
 257
 258         zone = page_zone(page);
 259         local_irq_save(flags);
 260         p = diff_pointer(zone, item);
 261
 262         (*p)++;
 263
 264         if (unlikely(*p > STAT_THRESHOLD)) {
 265                 zone_page_state_add(*p, zone, item);
 266                 *p = 0;
 267         }
 268         local_irq_restore(flags);
 269 }
 270 EXPORT_SYMBOL(inc_zone_page_state);
 271
 272 void dec_zone_page_state(struct page *page, enum zone_stat_item item)
 273 {
 274         unsigned long flags;
 275         struct zone *zone;
 276         s8 *p;
 277
 278         zone = page_zone(page);
 279         local_irq_save(flags);
 280         p = diff_pointer(zone, item);
 281
 282         (*p)--;
 283
 284         if (unlikely(*p < -STAT_THRESHOLD)) {
 285                 zone_page_state_add(*p, zone, item);
 286                 *p = 0;
 287         }
 288         local_irq_restore(flags);
 289 }
 290 EXPORT_SYMBOL(dec_zone_page_state);
 291
 292 /*
 293  * Update the zone counters for one cpu.
 294  */
 295 void refresh_cpu_vm_stats(int cpu)
 296 {
 297         struct zone *zone;
 298         int i;
 299         unsigned long flags;
 300
 301         for_each_zone(zone) {
 302                 struct per_cpu_pageset *pcp;
 303
 304                 pcp = zone_pcp(zone, cpu);
 305
 306                 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 307                         if (pcp->vm_stat_diff[i]) {
 308                                 local_irq_save(flags);
 309                                 zone_page_state_add(pcp->vm_stat_diff[i],
 310                                         zone, i);
 311                                 pcp->vm_stat_diff[i] = 0;
 312                                 local_irq_restore(flags);
 313                         }
 314         }
 315 }
 316
 317 static void __refresh_cpu_vm_stats(void *dummy)
 318 {
 319         refresh_cpu_vm_stats(smp_processor_id());
 320 }
 321
 322 /*
 323  * Consolidate all counters.
 324  *
 325  * Note that the result is less inaccurate but still inaccurate
 326  * if concurrent processes are allowed to run.
 327  */
 328 void refresh_vm_stats(void)
 329 {
 330         on_each_cpu(__refresh_cpu_vm_stats, NULL, 0, 1);
 331 }
 332 EXPORT_SYMBOL(refresh_vm_stats);
 333
 334 #endif
 335
 336 #ifdef CONFIG_PROC_FS
 337
 338 #include <linux/seq_file.h>
 339
 340 static void *frag_start(struct seq_file *m, loff_t *pos)
 341 {
 342         pg_data_t *pgdat;
 343         loff_t node = *pos;
 344         for (pgdat = first_online_pgdat();
 345              pgdat && node;
 346              pgdat = next_online_pgdat(pgdat))
 347                 --node;
 348
 349         return pgdat;
 350 }
 351
 352 static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
 353 {
 354         pg_data_t *pgdat = (pg_data_t *)arg;
 355
 356         (*pos)++;
 357         return next_online_pgdat(pgdat);
 358 }
 359
 360 static void frag_stop(struct seq_file *m, void *arg)
 361 {
 362 }
 363
 364 /*
 365  * This walks the free areas for each zone.
 366  */
 367 static int frag_show(struct seq_file *m, void *arg)
 368 {
 369         pg_data_t *pgdat = (pg_data_t *)arg;
 370         struct zone *zone;
 371         struct zone *node_zones = pgdat->node_zones;
 372         unsigned long flags;
 373         int order;
 374
 375         for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
 376                 if (!populated_zone(zone))
 377                         continue;
 378
 379                 spin_lock_irqsave(&zone->lock, flags);
 380                 seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
 381                 for (order = 0; order < MAX_ORDER; ++order)
 382                         seq_printf(m, "%6lu ", zone->free_area[order].nr_free);
 383                 spin_unlock_irqrestore(&zone->lock, flags);
 384                 seq_putc(m, '\n');
 385         }
 386         return 0;
 387 }
 388
 389 struct seq_operations fragmentation_op = {
 390         .start  = frag_start,
 391         .next   = frag_next,
 392         .stop   = frag_stop,
 393         .show   = frag_show,
 394 };
 395
 396 static char *vmstat_text[] = {
 397         /* Zoned VM counters */
 398         "nr_anon_pages",
 399         "nr_mapped",
 400         "nr_file_pages",
 401         "nr_slab",
 402         "nr_page_table_pages",
 403
 404         /* Page state */
 405         "nr_dirty",
 406         "nr_writeback",
 407         "nr_unstable",
 408
 409         "pgpgin",
 410         "pgpgout",
 411         "pswpin",
 412         "pswpout",
 413
 414         "pgalloc_high",
 415         "pgalloc_normal",
 416         "pgalloc_dma32",
 417         "pgalloc_dma",
 418
 419         "pgfree",
 420         "pgactivate",
 421         "pgdeactivate",
 422
 423         "pgfault",
 424         "pgmajfault",
 425
 426         "pgrefill_high",
 427         "pgrefill_normal",
 428         "pgrefill_dma32",
 429         "pgrefill_dma",
 430
 431         "pgsteal_high",
 432         "pgsteal_normal",
 433         "pgsteal_dma32",
 434         "pgsteal_dma",
 435
 436         "pgscan_kswapd_high",
 437         "pgscan_kswapd_normal",
 438         "pgscan_kswapd_dma32",
 439         "pgscan_kswapd_dma",
 440
 441         "pgscan_direct_high",
 442         "pgscan_direct_normal",
 443         "pgscan_direct_dma32",
 444         "pgscan_direct_dma",
 445
 446         "pginodesteal",
 447         "slabs_scanned",
 448         "kswapd_steal",
 449         "kswapd_inodesteal",
 450         "pageoutrun",
 451         "allocstall",
 452
 453         "pgrotated",
 454         "nr_bounce",
 455 };
 456
 457 /*
 458  * Output information about zones in @pgdat.
 459  */
 460 static int zoneinfo_show(struct seq_file *m, void *arg)
 461 {
 462         pg_data_t *pgdat = arg;
 463         struct zone *zone;
 464         struct zone *node_zones = pgdat->node_zones;
 465         unsigned long flags;
 466
 467         for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; zone++) {
 468                 int i;
 469
 470                 if (!populated_zone(zone))
 471                         continue;
 472
 473                 spin_lock_irqsave(&zone->lock, flags);
 474                 seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name);
 475                 seq_printf(m,
 476                            "\n  pages free     %lu"
 477                            "\n        min      %lu"
 478                            "\n        low      %lu"
 479                            "\n        high     %lu"
 480                            "\n        active   %lu"
 481                            "\n        inactive %lu"
 482                            "\n        scanned  %lu (a: %lu i: %lu)"
 483                            "\n        spanned  %lu"
 484                            "\n        present  %lu",
 485                            zone->free_pages,
 486                            zone->pages_min,
 487                            zone->pages_low,
 488                            zone->pages_high,
 489                            zone->nr_active,
 490                            zone->nr_inactive,
 491                            zone->pages_scanned,
 492                            zone->nr_scan_active, zone->nr_scan_inactive,
 493                            zone->spanned_pages,
 494                            zone->present_pages);
 495
 496                 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 497                         seq_printf(m, "\n    %-12s %lu", vmstat_text[i],
 498                                         zone_page_state(zone, i));
 499
 500                 seq_printf(m,
 501                            "\n        protection: (%lu",
 502                            zone->lowmem_reserve[0]);
 503                 for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++)
 504                         seq_printf(m, ", %lu", zone->lowmem_reserve[i]);
 505                 seq_printf(m,
 506                            ")"
 507                            "\n  pagesets");
 508                 for_each_online_cpu(i) {
 509                         struct per_cpu_pageset *pageset;
 510                         int j;
 511
 512                         pageset = zone_pcp(zone, i);
 513                         for (j = 0; j < ARRAY_SIZE(pageset->pcp); j++) {
 514                                 if (pageset->pcp[j].count)
 515                                         break;
 516                         }
 517                         if (j == ARRAY_SIZE(pageset->pcp))
 518                                 continue;
 519                         for (j = 0; j < ARRAY_SIZE(pageset->pcp); j++) {
 520                                 seq_printf(m,
 521                                            "\n    cpu: %i pcp: %i"
 522                                            "\n              count: %i"
 523                                            "\n              high:  %i"
 524                                            "\n              batch: %i",
 525                                            i, j,
 526                                            pageset->pcp[j].count,
 527                                            pageset->pcp[j].high,
 528                                            pageset->pcp[j].batch);
 529                         }
 530 #ifdef CONFIG_NUMA
 531                         seq_printf(m,
 532                                    "\n            numa_hit:       %lu"
 533                                    "\n            numa_miss:      %lu"
 534                                    "\n            numa_foreign:   %lu"
 535                                    "\n            interleave_hit: %lu"
 536                                    "\n            local_node:     %lu"
 537                                    "\n            other_node:     %lu",
 538                                    pageset->numa_hit,
 539                                    pageset->numa_miss,
 540                                    pageset->numa_foreign,
 541                                    pageset->interleave_hit,
 542                                    pageset->local_node,
 543                                    pageset->other_node);
 544 #endif
 545                 }
 546                 seq_printf(m,
 547                            "\n  all_unreclaimable: %u"
 548                            "\n  prev_priority:     %i"
 549                            "\n  temp_priority:     %i"
 550                            "\n  start_pfn:         %lu",
 551                            zone->all_unreclaimable,
 552                            zone->prev_priority,
 553                            zone->temp_priority,
 554                            zone->zone_start_pfn);
 555                 spin_unlock_irqrestore(&zone->lock, flags);
 556                 seq_putc(m, '\n');
 557         }
 558         return 0;
 559 }
 560
 561 struct seq_operations zoneinfo_op = {
 562         .start  = frag_start, /* iterate over all zones. The same as in
 563                                * fragmentation. */
 564         .next   = frag_next,
 565         .stop   = frag_stop,
 566         .show   = zoneinfo_show,
 567 };
 568
 569 static void *vmstat_start(struct seq_file *m, loff_t *pos)
 570 {
 571         unsigned long *v;
 572         struct page_state *ps;
 573         int i;
 574
 575         if (*pos >= ARRAY_SIZE(vmstat_text))
 576                 return NULL;
 577
 578         v = kmalloc(NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long)
 579                         + sizeof(*ps), GFP_KERNEL);
 580         m->private = v;
 581         if (!v)
 582                 return ERR_PTR(-ENOMEM);
 583         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 584                 v[i] = global_page_state(i);
 585         ps = (struct page_state *)(v + NR_VM_ZONE_STAT_ITEMS);
 586         get_full_page_state(ps);
 587         ps->pgpgin /= 2;                /* sectors -> kbytes */
 588         ps->pgpgout /= 2;
 589         return v + *pos;
 590 }
 591
 592 static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)
 593 {
 594         (*pos)++;
 595         if (*pos >= ARRAY_SIZE(vmstat_text))
 596                 return NULL;
 597         return (unsigned long *)m->private + *pos;
 598 }
 599
 600 static int vmstat_show(struct seq_file *m, void *arg)
 601 {
 602         unsigned long *l = arg;
 603         unsigned long off = l - (unsigned long *)m->private;
 604
 605         seq_printf(m, "%s %lu\n", vmstat_text[off], *l);
 606         return 0;
 607 }
 608
 609 static void vmstat_stop(struct seq_file *m, void *arg)
 610 {
 611         kfree(m->private);
 612         m->private = NULL;
 613 }
 614
 615 struct seq_operations vmstat_op = {
 616         .start  = vmstat_start,
 617         .next   = vmstat_next,
 618         .stop   = vmstat_stop,
 619         .show   = vmstat_show,
 620 };
 621
 622 #endif /* CONFIG_PROC_FS */
 623