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