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/module.h> 14 #include <linux/cpu.h> 15 16 void __get_zone_counts(unsigned long *active, unsigned long *inactive, 17 unsigned long *free, struct pglist_data *pgdat) 18 { 19 struct zone *zones = pgdat->node_zones; 20 int i; 21 22 *active = 0; 23 *inactive = 0; 24 *free = 0; 25 for (i = 0; i < MAX_NR_ZONES; i++) { 26 *active += zones[i].nr_active; 27 *inactive += zones[i].nr_inactive; 28 *free += zones[i].free_pages; 29 } 30 } 31 32 void get_zone_counts(unsigned long *active, 33 unsigned long *inactive, unsigned long *free) 34 { 35 struct pglist_data *pgdat; 36 37 *active = 0; 38 *inactive = 0; 39 *free = 0; 40 for_each_online_pgdat(pgdat) { 41 unsigned long l, m, n; 42 __get_zone_counts(&l, &m, &n, pgdat); 43 *active += l; 44 *inactive += m; 45 *free += n; 46 } 47 } 48 49 #ifdef CONFIG_VM_EVENT_COUNTERS 50 DEFINE_PER_CPU(struct vm_event_state, vm_event_states) = {{0}}; 51 EXPORT_PER_CPU_SYMBOL(vm_event_states); 52 53 static void sum_vm_events(unsigned long *ret, cpumask_t *cpumask) 54 { 55 int cpu = 0; 56 int i; 57 58 memset(ret, 0, NR_VM_EVENT_ITEMS * sizeof(unsigned long)); 59 60 cpu = first_cpu(*cpumask); 61 while (cpu < NR_CPUS) { 62 struct vm_event_state *this = &per_cpu(vm_event_states, cpu); 63 64 cpu = next_cpu(cpu, *cpumask); 65 66 if (cpu < NR_CPUS) 67 prefetch(&per_cpu(vm_event_states, cpu)); 68 69 70 for (i = 0; i < NR_VM_EVENT_ITEMS; i++) 71 ret[i] += this->event[i]; 72 } 73 } 74 75 /* 76 * Accumulate the vm event counters across all CPUs. 77 * The result is unavoidably approximate - it can change 78 * during and after execution of this function. 79 */ 80 void all_vm_events(unsigned long *ret) 81 { 82 sum_vm_events(ret, &cpu_online_map); 83 } 84 EXPORT_SYMBOL_GPL(all_vm_events); 85 86 #ifdef CONFIG_HOTPLUG 87 /* 88 * Fold the foreign cpu events into our own. 89 * 90 * This is adding to the events on one processor 91 * but keeps the global counts constant. 92 */ 93 void vm_events_fold_cpu(int cpu) 94 { 95 struct vm_event_state *fold_state = &per_cpu(vm_event_states, cpu); 96 int i; 97 98 for (i = 0; i < NR_VM_EVENT_ITEMS; i++) { 99 count_vm_events(i, fold_state->event[i]); 100 fold_state->event[i] = 0; 101 } 102 } 103 #endif /* CONFIG_HOTPLUG */ 104 105 #endif /* CONFIG_VM_EVENT_COUNTERS */ 106 107 /* 108 * Manage combined zone based / global counters 109 * 110 * vm_stat contains the global counters 111 */ 112 atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS]; 113 EXPORT_SYMBOL(vm_stat); 114 115 #ifdef CONFIG_SMP 116 117 static int calculate_threshold(struct zone *zone) 118 { 119 int threshold; 120 int mem; /* memory in 128 MB units */ 121 122 /* 123 * The threshold scales with the number of processors and the amount 124 * of memory per zone. More memory means that we can defer updates for 125 * longer, more processors could lead to more contention. 126 * fls() is used to have a cheap way of logarithmic scaling. 127 * 128 * Some sample thresholds: 129 * 130 * Threshold Processors (fls) Zonesize fls(mem+1) 131 * ------------------------------------------------------------------ 132 * 8 1 1 0.9-1 GB 4 133 * 16 2 2 0.9-1 GB 4 134 * 20 2 2 1-2 GB 5 135 * 24 2 2 2-4 GB 6 136 * 28 2 2 4-8 GB 7 137 * 32 2 2 8-16 GB 8 138 * 4 2 2 <128M 1 139 * 30 4 3 2-4 GB 5 140 * 48 4 3 8-16 GB 8 141 * 32 8 4 1-2 GB 4 142 * 32 8 4 0.9-1GB 4 143 * 10 16 5 <128M 1 144 * 40 16 5 900M 4 145 * 70 64 7 2-4 GB 5 146 * 84 64 7 4-8 GB 6 147 * 108 512 9 4-8 GB 6 148 * 125 1024 10 8-16 GB 8 149 * 125 1024 10 16-32 GB 9 150 */ 151 152 mem = zone->present_pages >> (27 - PAGE_SHIFT); 153 154 threshold = 2 * fls(num_online_cpus()) * (1 + fls(mem)); 155 156 /* 157 * Maximum threshold is 125 158 */ 159 threshold = min(125, threshold); 160 161 return threshold; 162 } 163 164 /* 165 * Refresh the thresholds for each zone. 166 */ 167 static void refresh_zone_stat_thresholds(void) 168 { 169 struct zone *zone; 170 int cpu; 171 int threshold; 172 173 for_each_zone(zone) { 174 175 if (!zone->present_pages) 176 continue; 177 178 threshold = calculate_threshold(zone); 179 180 for_each_online_cpu(cpu) 181 zone_pcp(zone, cpu)->stat_threshold = threshold; 182 } 183 } 184 185 /* 186 * For use when we know that interrupts are disabled. 187 */ 188 void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item, 189 int delta) 190 { 191 struct per_cpu_pageset *pcp = zone_pcp(zone, smp_processor_id()); 192 s8 *p = pcp->vm_stat_diff + item; 193 long x; 194 195 x = delta + *p; 196 197 if (unlikely(x > pcp->stat_threshold || x < -pcp->stat_threshold)) { 198 zone_page_state_add(x, zone, item); 199 x = 0; 200 } 201 *p = x; 202 } 203 EXPORT_SYMBOL(__mod_zone_page_state); 204 205 /* 206 * For an unknown interrupt state 207 */ 208 void mod_zone_page_state(struct zone *zone, enum zone_stat_item item, 209 int delta) 210 { 211 unsigned long flags; 212 213 local_irq_save(flags); 214 __mod_zone_page_state(zone, item, delta); 215 local_irq_restore(flags); 216 } 217 EXPORT_SYMBOL(mod_zone_page_state); 218 219 /* 220 * Optimized increment and decrement functions. 221 * 222 * These are only for a single page and therefore can take a struct page * 223 * argument instead of struct zone *. This allows the inclusion of the code 224 * generated for page_zone(page) into the optimized functions. 225 * 226 * No overflow check is necessary and therefore the differential can be 227 * incremented or decremented in place which may allow the compilers to 228 * generate better code. 229 * The increment or decrement is known and therefore one boundary check can 230 * be omitted. 231 * 232 * NOTE: These functions are very performance sensitive. Change only 233 * with care. 234 * 235 * Some processors have inc/dec instructions that are atomic vs an interrupt. 236 * However, the code must first determine the differential location in a zone 237 * based on the processor number and then inc/dec the counter. There is no 238 * guarantee without disabling preemption that the processor will not change 239 * in between and therefore the atomicity vs. interrupt cannot be exploited 240 * in a useful way here. 241 */ 242 static void __inc_zone_state(struct zone *zone, enum zone_stat_item item) 243 { 244 struct per_cpu_pageset *pcp = zone_pcp(zone, smp_processor_id()); 245 s8 *p = pcp->vm_stat_diff + item; 246 247 (*p)++; 248 249 if (unlikely(*p > pcp->stat_threshold)) { 250 int overstep = pcp->stat_threshold / 2; 251 252 zone_page_state_add(*p + overstep, zone, item); 253 *p = -overstep; 254 } 255 } 256 257 void __inc_zone_page_state(struct page *page, enum zone_stat_item item) 258 { 259 __inc_zone_state(page_zone(page), item); 260 } 261 EXPORT_SYMBOL(__inc_zone_page_state); 262 263 void __dec_zone_page_state(struct page *page, enum zone_stat_item item) 264 { 265 struct zone *zone = page_zone(page); 266 struct per_cpu_pageset *pcp = zone_pcp(zone, smp_processor_id()); 267 s8 *p = pcp->vm_stat_diff + item; 268 269 (*p)--; 270 271 if (unlikely(*p < - pcp->stat_threshold)) { 272 int overstep = pcp->stat_threshold / 2; 273 274 zone_page_state_add(*p - overstep, zone, item); 275 *p = overstep; 276 } 277 } 278 EXPORT_SYMBOL(__dec_zone_page_state); 279 280 void inc_zone_state(struct zone *zone, enum zone_stat_item item) 281 { 282 unsigned long flags; 283 284 local_irq_save(flags); 285 __inc_zone_state(zone, item); 286 local_irq_restore(flags); 287 } 288 289 void inc_zone_page_state(struct page *page, enum zone_stat_item item) 290 { 291 unsigned long flags; 292 struct zone *zone; 293 294 zone = page_zone(page); 295 local_irq_save(flags); 296 __inc_zone_state(zone, item); 297 local_irq_restore(flags); 298 } 299 EXPORT_SYMBOL(inc_zone_page_state); 300 301 void dec_zone_page_state(struct page *page, enum zone_stat_item item) 302 { 303 unsigned long flags; 304 305 local_irq_save(flags); 306 __dec_zone_page_state(page, item); 307 local_irq_restore(flags); 308 } 309 EXPORT_SYMBOL(dec_zone_page_state); 310 311 /* 312 * Update the zone counters for one cpu. 313 */ 314 void refresh_cpu_vm_stats(int cpu) 315 { 316 struct zone *zone; 317 int i; 318 unsigned long flags; 319 320 for_each_zone(zone) { 321 struct per_cpu_pageset *pcp; 322 323 if (!populated_zone(zone)) 324 continue; 325 326 pcp = zone_pcp(zone, cpu); 327 328 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) 329 if (pcp->vm_stat_diff[i]) { 330 local_irq_save(flags); 331 zone_page_state_add(pcp->vm_stat_diff[i], 332 zone, i); 333 pcp->vm_stat_diff[i] = 0; 334 local_irq_restore(flags); 335 } 336 } 337 } 338 339 static void __refresh_cpu_vm_stats(void *dummy) 340 { 341 refresh_cpu_vm_stats(smp_processor_id()); 342 } 343 344 /* 345 * Consolidate all counters. 346 * 347 * Note that the result is less inaccurate but still inaccurate 348 * if concurrent processes are allowed to run. 349 */ 350 void refresh_vm_stats(void) 351 { 352 on_each_cpu(__refresh_cpu_vm_stats, NULL, 0, 1); 353 } 354 EXPORT_SYMBOL(refresh_vm_stats); 355 356 #endif 357 358 #ifdef CONFIG_NUMA 359 /* 360 * zonelist = the list of zones passed to the allocator 361 * z = the zone from which the allocation occurred. 362 * 363 * Must be called with interrupts disabled. 364 */ 365 void zone_statistics(struct zonelist *zonelist, struct zone *z) 366 { 367 if (z->zone_pgdat == zonelist->zones[0]->zone_pgdat) { 368 __inc_zone_state(z, NUMA_HIT); 369 } else { 370 __inc_zone_state(z, NUMA_MISS); 371 __inc_zone_state(zonelist->zones[0], NUMA_FOREIGN); 372 } 373 if (z->node == numa_node_id()) 374 __inc_zone_state(z, NUMA_LOCAL); 375 else 376 __inc_zone_state(z, NUMA_OTHER); 377 } 378 #endif 379 380 #ifdef CONFIG_PROC_FS 381 382 #include <linux/seq_file.h> 383 384 static void *frag_start(struct seq_file *m, loff_t *pos) 385 { 386 pg_data_t *pgdat; 387 loff_t node = *pos; 388 for (pgdat = first_online_pgdat(); 389 pgdat && node; 390 pgdat = next_online_pgdat(pgdat)) 391 --node; 392 393 return pgdat; 394 } 395 396 static void *frag_next(struct seq_file *m, void *arg, loff_t *pos) 397 { 398 pg_data_t *pgdat = (pg_data_t *)arg; 399 400 (*pos)++; 401 return next_online_pgdat(pgdat); 402 } 403 404 static void frag_stop(struct seq_file *m, void *arg) 405 { 406 } 407 408 /* 409 * This walks the free areas for each zone. 410 */ 411 static int frag_show(struct seq_file *m, void *arg) 412 { 413 pg_data_t *pgdat = (pg_data_t *)arg; 414 struct zone *zone; 415 struct zone *node_zones = pgdat->node_zones; 416 unsigned long flags; 417 int order; 418 419 for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) { 420 if (!populated_zone(zone)) 421 continue; 422 423 spin_lock_irqsave(&zone->lock, flags); 424 seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name); 425 for (order = 0; order < MAX_ORDER; ++order) 426 seq_printf(m, "%6lu ", zone->free_area[order].nr_free); 427 spin_unlock_irqrestore(&zone->lock, flags); 428 seq_putc(m, '\n'); 429 } 430 return 0; 431 } 432 433 const struct seq_operations fragmentation_op = { 434 .start = frag_start, 435 .next = frag_next, 436 .stop = frag_stop, 437 .show = frag_show, 438 }; 439 440 #ifdef CONFIG_ZONE_DMA32 441 #define TEXT_FOR_DMA32(xx) xx "_dma32", 442 #else 443 #define TEXT_FOR_DMA32(xx) 444 #endif 445 446 #ifdef CONFIG_HIGHMEM 447 #define TEXT_FOR_HIGHMEM(xx) xx "_high", 448 #else 449 #define TEXT_FOR_HIGHMEM(xx) 450 #endif 451 452 #define TEXTS_FOR_ZONES(xx) xx "_dma", TEXT_FOR_DMA32(xx) xx "_normal", \ 453 TEXT_FOR_HIGHMEM(xx) 454 455 static const char * const vmstat_text[] = { 456 /* Zoned VM counters */ 457 "nr_anon_pages", 458 "nr_mapped", 459 "nr_file_pages", 460 "nr_slab_reclaimable", 461 "nr_slab_unreclaimable", 462 "nr_page_table_pages", 463 "nr_dirty", 464 "nr_writeback", 465 "nr_unstable", 466 "nr_bounce", 467 "nr_vmscan_write", 468 469 #ifdef CONFIG_NUMA 470 "numa_hit", 471 "numa_miss", 472 "numa_foreign", 473 "numa_interleave", 474 "numa_local", 475 "numa_other", 476 #endif 477 478 #ifdef CONFIG_VM_EVENT_COUNTERS 479 "pgpgin", 480 "pgpgout", 481 "pswpin", 482 "pswpout", 483 484 TEXTS_FOR_ZONES("pgalloc") 485 486 "pgfree", 487 "pgactivate", 488 "pgdeactivate", 489 490 "pgfault", 491 "pgmajfault", 492 493 TEXTS_FOR_ZONES("pgrefill") 494 TEXTS_FOR_ZONES("pgsteal") 495 TEXTS_FOR_ZONES("pgscan_kswapd") 496 TEXTS_FOR_ZONES("pgscan_direct") 497 498 "pginodesteal", 499 "slabs_scanned", 500 "kswapd_steal", 501 "kswapd_inodesteal", 502 "pageoutrun", 503 "allocstall", 504 505 "pgrotated", 506 #endif 507 }; 508 509 /* 510 * Output information about zones in @pgdat. 511 */ 512 static int zoneinfo_show(struct seq_file *m, void *arg) 513 { 514 pg_data_t *pgdat = arg; 515 struct zone *zone; 516 struct zone *node_zones = pgdat->node_zones; 517 unsigned long flags; 518 519 for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; zone++) { 520 int i; 521 522 if (!populated_zone(zone)) 523 continue; 524 525 spin_lock_irqsave(&zone->lock, flags); 526 seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name); 527 seq_printf(m, 528 "\n pages free %lu" 529 "\n min %lu" 530 "\n low %lu" 531 "\n high %lu" 532 "\n active %lu" 533 "\n inactive %lu" 534 "\n scanned %lu (a: %lu i: %lu)" 535 "\n spanned %lu" 536 "\n present %lu", 537 zone->free_pages, 538 zone->pages_min, 539 zone->pages_low, 540 zone->pages_high, 541 zone->nr_active, 542 zone->nr_inactive, 543 zone->pages_scanned, 544 zone->nr_scan_active, zone->nr_scan_inactive, 545 zone->spanned_pages, 546 zone->present_pages); 547 548 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) 549 seq_printf(m, "\n %-12s %lu", vmstat_text[i], 550 zone_page_state(zone, i)); 551 552 seq_printf(m, 553 "\n protection: (%lu", 554 zone->lowmem_reserve[0]); 555 for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++) 556 seq_printf(m, ", %lu", zone->lowmem_reserve[i]); 557 seq_printf(m, 558 ")" 559 "\n pagesets"); 560 for_each_online_cpu(i) { 561 struct per_cpu_pageset *pageset; 562 int j; 563 564 pageset = zone_pcp(zone, i); 565 for (j = 0; j < ARRAY_SIZE(pageset->pcp); j++) { 566 if (pageset->pcp[j].count) 567 break; 568 } 569 if (j == ARRAY_SIZE(pageset->pcp)) 570 continue; 571 for (j = 0; j < ARRAY_SIZE(pageset->pcp); j++) { 572 seq_printf(m, 573 "\n cpu: %i pcp: %i" 574 "\n count: %i" 575 "\n high: %i" 576 "\n batch: %i", 577 i, j, 578 pageset->pcp[j].count, 579 pageset->pcp[j].high, 580 pageset->pcp[j].batch); 581 } 582 #ifdef CONFIG_SMP 583 seq_printf(m, "\n vm stats threshold: %d", 584 pageset->stat_threshold); 585 #endif 586 } 587 seq_printf(m, 588 "\n all_unreclaimable: %u" 589 "\n prev_priority: %i" 590 "\n start_pfn: %lu", 591 zone->all_unreclaimable, 592 zone->prev_priority, 593 zone->zone_start_pfn); 594 spin_unlock_irqrestore(&zone->lock, flags); 595 seq_putc(m, '\n'); 596 } 597 return 0; 598 } 599 600 const struct seq_operations zoneinfo_op = { 601 .start = frag_start, /* iterate over all zones. The same as in 602 * fragmentation. */ 603 .next = frag_next, 604 .stop = frag_stop, 605 .show = zoneinfo_show, 606 }; 607 608 static void *vmstat_start(struct seq_file *m, loff_t *pos) 609 { 610 unsigned long *v; 611 #ifdef CONFIG_VM_EVENT_COUNTERS 612 unsigned long *e; 613 #endif 614 int i; 615 616 if (*pos >= ARRAY_SIZE(vmstat_text)) 617 return NULL; 618 619 #ifdef CONFIG_VM_EVENT_COUNTERS 620 v = kmalloc(NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long) 621 + sizeof(struct vm_event_state), GFP_KERNEL); 622 #else 623 v = kmalloc(NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long), 624 GFP_KERNEL); 625 #endif 626 m->private = v; 627 if (!v) 628 return ERR_PTR(-ENOMEM); 629 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) 630 v[i] = global_page_state(i); 631 #ifdef CONFIG_VM_EVENT_COUNTERS 632 e = v + NR_VM_ZONE_STAT_ITEMS; 633 all_vm_events(e); 634 e[PGPGIN] /= 2; /* sectors -> kbytes */ 635 e[PGPGOUT] /= 2; 636 #endif 637 return v + *pos; 638 } 639 640 static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos) 641 { 642 (*pos)++; 643 if (*pos >= ARRAY_SIZE(vmstat_text)) 644 return NULL; 645 return (unsigned long *)m->private + *pos; 646 } 647 648 static int vmstat_show(struct seq_file *m, void *arg) 649 { 650 unsigned long *l = arg; 651 unsigned long off = l - (unsigned long *)m->private; 652 653 seq_printf(m, "%s %lu\n", vmstat_text[off], *l); 654 return 0; 655 } 656 657 static void vmstat_stop(struct seq_file *m, void *arg) 658 { 659 kfree(m->private); 660 m->private = NULL; 661 } 662 663 const struct seq_operations vmstat_op = { 664 .start = vmstat_start, 665 .next = vmstat_next, 666 .stop = vmstat_stop, 667 .show = vmstat_show, 668 }; 669 670 #endif /* CONFIG_PROC_FS */ 671 672 #ifdef CONFIG_SMP 673 /* 674 * Use the cpu notifier to insure that the thresholds are recalculated 675 * when necessary. 676 */ 677 static int __cpuinit vmstat_cpuup_callback(struct notifier_block *nfb, 678 unsigned long action, 679 void *hcpu) 680 { 681 switch (action) { 682 case CPU_UP_PREPARE: 683 case CPU_UP_CANCELED: 684 case CPU_DEAD: 685 refresh_zone_stat_thresholds(); 686 break; 687 default: 688 break; 689 } 690 return NOTIFY_OK; 691 } 692 693 static struct notifier_block __cpuinitdata vmstat_notifier = 694 { &vmstat_cpuup_callback, NULL, 0 }; 695 696 int __init setup_vmstat(void) 697 { 698 refresh_zone_stat_thresholds(); 699 register_cpu_notifier(&vmstat_notifier); 700 return 0; 701 } 702 module_init(setup_vmstat) 703 #endif 704