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