linux/mm/vmstat.c
<<
>>
Prefs
   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#include <linux/fs.h>
  12#include <linux/mm.h>
  13#include <linux/err.h>
  14#include <linux/module.h>
  15#include <linux/slab.h>
  16#include <linux/cpu.h>
  17#include <linux/vmstat.h>
  18#include <linux/sched.h>
  19#include <linux/math64.h>
  20#include <linux/writeback.h>
  21#include <linux/compaction.h>
  22
  23#ifdef CONFIG_VM_EVENT_COUNTERS
  24DEFINE_PER_CPU(struct vm_event_state, vm_event_states) = {{0}};
  25EXPORT_PER_CPU_SYMBOL(vm_event_states);
  26
  27static void sum_vm_events(unsigned long *ret)
  28{
  29        int cpu;
  30        int i;
  31
  32        memset(ret, 0, NR_VM_EVENT_ITEMS * sizeof(unsigned long));
  33
  34        for_each_online_cpu(cpu) {
  35                struct vm_event_state *this = &per_cpu(vm_event_states, cpu);
  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*/
  47void all_vm_events(unsigned long *ret)
  48{
  49        get_online_cpus();
  50        sum_vm_events(ret);
  51        put_online_cpus();
  52}
  53EXPORT_SYMBOL_GPL(all_vm_events);
  54
  55#ifdef CONFIG_HOTPLUG
  56/*
  57 * Fold the foreign cpu events into our own.
  58 *
  59 * This is adding to the events on one processor
  60 * but keeps the global counts constant.
  61 */
  62void vm_events_fold_cpu(int cpu)
  63{
  64        struct vm_event_state *fold_state = &per_cpu(vm_event_states, cpu);
  65        int i;
  66
  67        for (i = 0; i < NR_VM_EVENT_ITEMS; i++) {
  68                count_vm_events(i, fold_state->event[i]);
  69                fold_state->event[i] = 0;
  70        }
  71}
  72#endif /* CONFIG_HOTPLUG */
  73
  74#endif /* CONFIG_VM_EVENT_COUNTERS */
  75
  76/*
  77 * Manage combined zone based / global counters
  78 *
  79 * vm_stat contains the global counters
  80 */
  81atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS];
  82EXPORT_SYMBOL(vm_stat);
  83
  84#ifdef CONFIG_SMP
  85
  86int calculate_pressure_threshold(struct zone *zone)
  87{
  88        int threshold;
  89        int watermark_distance;
  90
  91        /*
  92         * As vmstats are not up to date, there is drift between the estimated
  93         * and real values. For high thresholds and a high number of CPUs, it
  94         * is possible for the min watermark to be breached while the estimated
  95         * value looks fine. The pressure threshold is a reduced value such
  96         * that even the maximum amount of drift will not accidentally breach
  97         * the min watermark
  98         */
  99        watermark_distance = low_wmark_pages(zone) - min_wmark_pages(zone);
 100        threshold = max(1, (int)(watermark_distance / num_online_cpus()));
 101
 102        /*
 103         * Maximum threshold is 125
 104         */
 105        threshold = min(125, threshold);
 106
 107        return threshold;
 108}
 109
 110int calculate_normal_threshold(struct zone *zone)
 111{
 112        int threshold;
 113        int mem;        /* memory in 128 MB units */
 114
 115        /*
 116         * The threshold scales with the number of processors and the amount
 117         * of memory per zone. More memory means that we can defer updates for
 118         * longer, more processors could lead to more contention.
 119         * fls() is used to have a cheap way of logarithmic scaling.
 120         *
 121         * Some sample thresholds:
 122         *
 123         * Threshold    Processors      (fls)   Zonesize        fls(mem+1)
 124         * ------------------------------------------------------------------
 125         * 8            1               1       0.9-1 GB        4
 126         * 16           2               2       0.9-1 GB        4
 127         * 20           2               2       1-2 GB          5
 128         * 24           2               2       2-4 GB          6
 129         * 28           2               2       4-8 GB          7
 130         * 32           2               2       8-16 GB         8
 131         * 4            2               2       <128M           1
 132         * 30           4               3       2-4 GB          5
 133         * 48           4               3       8-16 GB         8
 134         * 32           8               4       1-2 GB          4
 135         * 32           8               4       0.9-1GB         4
 136         * 10           16              5       <128M           1
 137         * 40           16              5       900M            4
 138         * 70           64              7       2-4 GB          5
 139         * 84           64              7       4-8 GB          6
 140         * 108          512             9       4-8 GB          6
 141         * 125          1024            10      8-16 GB         8
 142         * 125          1024            10      16-32 GB        9
 143         */
 144
 145        mem = zone->present_pages >> (27 - PAGE_SHIFT);
 146
 147        threshold = 2 * fls(num_online_cpus()) * (1 + fls(mem));
 148
 149        /*
 150         * Maximum threshold is 125
 151         */
 152        threshold = min(125, threshold);
 153
 154        return threshold;
 155}
 156
 157/*
 158 * Refresh the thresholds for each zone.
 159 */
 160void refresh_zone_stat_thresholds(void)
 161{
 162        struct zone *zone;
 163        int cpu;
 164        int threshold;
 165
 166        for_each_populated_zone(zone) {
 167                unsigned long max_drift, tolerate_drift;
 168
 169                threshold = calculate_normal_threshold(zone);
 170
 171                for_each_online_cpu(cpu)
 172                        per_cpu_ptr(zone->pageset, cpu)->stat_threshold
 173                                                        = threshold;
 174
 175                /*
 176                 * Only set percpu_drift_mark if there is a danger that
 177                 * NR_FREE_PAGES reports the low watermark is ok when in fact
 178                 * the min watermark could be breached by an allocation
 179                 */
 180                tolerate_drift = low_wmark_pages(zone) - min_wmark_pages(zone);
 181                max_drift = num_online_cpus() * threshold;
 182                if (max_drift > tolerate_drift)
 183                        zone->percpu_drift_mark = high_wmark_pages(zone) +
 184                                        max_drift;
 185        }
 186}
 187
 188void set_pgdat_percpu_threshold(pg_data_t *pgdat,
 189                                int (*calculate_pressure)(struct zone *))
 190{
 191        struct zone *zone;
 192        int cpu;
 193        int threshold;
 194        int i;
 195
 196        for (i = 0; i < pgdat->nr_zones; i++) {
 197                zone = &pgdat->node_zones[i];
 198                if (!zone->percpu_drift_mark)
 199                        continue;
 200
 201                threshold = (*calculate_pressure)(zone);
 202                for_each_possible_cpu(cpu)
 203                        per_cpu_ptr(zone->pageset, cpu)->stat_threshold
 204                                                        = threshold;
 205        }
 206}
 207
 208/*
 209 * For use when we know that interrupts are disabled.
 210 */
 211void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 212                                int delta)
 213{
 214        struct per_cpu_pageset __percpu *pcp = zone->pageset;
 215        s8 __percpu *p = pcp->vm_stat_diff + item;
 216        long x;
 217        long t;
 218
 219        x = delta + __this_cpu_read(*p);
 220
 221        t = __this_cpu_read(pcp->stat_threshold);
 222
 223        if (unlikely(x > t || x < -t)) {
 224                zone_page_state_add(x, zone, item);
 225                x = 0;
 226        }
 227        __this_cpu_write(*p, x);
 228}
 229EXPORT_SYMBOL(__mod_zone_page_state);
 230
 231/*
 232 * Optimized increment and decrement functions.
 233 *
 234 * These are only for a single page and therefore can take a struct page *
 235 * argument instead of struct zone *. This allows the inclusion of the code
 236 * generated for page_zone(page) into the optimized functions.
 237 *
 238 * No overflow check is necessary and therefore the differential can be
 239 * incremented or decremented in place which may allow the compilers to
 240 * generate better code.
 241 * The increment or decrement is known and therefore one boundary check can
 242 * be omitted.
 243 *
 244 * NOTE: These functions are very performance sensitive. Change only
 245 * with care.
 246 *
 247 * Some processors have inc/dec instructions that are atomic vs an interrupt.
 248 * However, the code must first determine the differential location in a zone
 249 * based on the processor number and then inc/dec the counter. There is no
 250 * guarantee without disabling preemption that the processor will not change
 251 * in between and therefore the atomicity vs. interrupt cannot be exploited
 252 * in a useful way here.
 253 */
 254void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
 255{
 256        struct per_cpu_pageset __percpu *pcp = zone->pageset;
 257        s8 __percpu *p = pcp->vm_stat_diff + item;
 258        s8 v, t;
 259
 260        v = __this_cpu_inc_return(*p);
 261        t = __this_cpu_read(pcp->stat_threshold);
 262        if (unlikely(v > t)) {
 263                s8 overstep = t >> 1;
 264
 265                zone_page_state_add(v + overstep, zone, item);
 266                __this_cpu_write(*p, -overstep);
 267        }
 268}
 269
 270void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
 271{
 272        __inc_zone_state(page_zone(page), item);
 273}
 274EXPORT_SYMBOL(__inc_zone_page_state);
 275
 276void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
 277{
 278        struct per_cpu_pageset __percpu *pcp = zone->pageset;
 279        s8 __percpu *p = pcp->vm_stat_diff + item;
 280        s8 v, t;
 281
 282        v = __this_cpu_dec_return(*p);
 283        t = __this_cpu_read(pcp->stat_threshold);
 284        if (unlikely(v < - t)) {
 285                s8 overstep = t >> 1;
 286
 287                zone_page_state_add(v - overstep, zone, item);
 288                __this_cpu_write(*p, overstep);
 289        }
 290}
 291
 292void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
 293{
 294        __dec_zone_state(page_zone(page), item);
 295}
 296EXPORT_SYMBOL(__dec_zone_page_state);
 297
 298#ifdef CONFIG_CMPXCHG_LOCAL
 299/*
 300 * If we have cmpxchg_local support then we do not need to incur the overhead
 301 * that comes with local_irq_save/restore if we use this_cpu_cmpxchg.
 302 *
 303 * mod_state() modifies the zone counter state through atomic per cpu
 304 * operations.
 305 *
 306 * Overstep mode specifies how overstep should handled:
 307 *     0       No overstepping
 308 *     1       Overstepping half of threshold
 309 *     -1      Overstepping minus half of threshold
 310*/
 311static inline void mod_state(struct zone *zone,
 312       enum zone_stat_item item, int delta, int overstep_mode)
 313{
 314        struct per_cpu_pageset __percpu *pcp = zone->pageset;
 315        s8 __percpu *p = pcp->vm_stat_diff + item;
 316        long o, n, t, z;
 317
 318        do {
 319                z = 0;  /* overflow to zone counters */
 320
 321                /*
 322                 * The fetching of the stat_threshold is racy. We may apply
 323                 * a counter threshold to the wrong the cpu if we get
 324                 * rescheduled while executing here. However, the next
 325                 * counter update will apply the threshold again and
 326                 * therefore bring the counter under the threshold again.
 327                 *
 328                 * Most of the time the thresholds are the same anyways
 329                 * for all cpus in a zone.
 330                 */
 331                t = this_cpu_read(pcp->stat_threshold);
 332
 333                o = this_cpu_read(*p);
 334                n = delta + o;
 335
 336                if (n > t || n < -t) {
 337                        int os = overstep_mode * (t >> 1) ;
 338
 339                        /* Overflow must be added to zone counters */
 340                        z = n + os;
 341                        n = -os;
 342                }
 343        } while (this_cpu_cmpxchg(*p, o, n) != o);
 344
 345        if (z)
 346                zone_page_state_add(z, zone, item);
 347}
 348
 349void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 350                                        int delta)
 351{
 352        mod_state(zone, item, delta, 0);
 353}
 354EXPORT_SYMBOL(mod_zone_page_state);
 355
 356void inc_zone_state(struct zone *zone, enum zone_stat_item item)
 357{
 358        mod_state(zone, item, 1, 1);
 359}
 360
 361void inc_zone_page_state(struct page *page, enum zone_stat_item item)
 362{
 363        mod_state(page_zone(page), item, 1, 1);
 364}
 365EXPORT_SYMBOL(inc_zone_page_state);
 366
 367void dec_zone_page_state(struct page *page, enum zone_stat_item item)
 368{
 369        mod_state(page_zone(page), item, -1, -1);
 370}
 371EXPORT_SYMBOL(dec_zone_page_state);
 372#else
 373/*
 374 * Use interrupt disable to serialize counter updates
 375 */
 376void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
 377                                        int delta)
 378{
 379        unsigned long flags;
 380
 381        local_irq_save(flags);
 382        __mod_zone_page_state(zone, item, delta);
 383        local_irq_restore(flags);
 384}
 385EXPORT_SYMBOL(mod_zone_page_state);
 386
 387void inc_zone_state(struct zone *zone, enum zone_stat_item item)
 388{
 389        unsigned long flags;
 390
 391        local_irq_save(flags);
 392        __inc_zone_state(zone, item);
 393        local_irq_restore(flags);
 394}
 395
 396void inc_zone_page_state(struct page *page, enum zone_stat_item item)
 397{
 398        unsigned long flags;
 399        struct zone *zone;
 400
 401        zone = page_zone(page);
 402        local_irq_save(flags);
 403        __inc_zone_state(zone, item);
 404        local_irq_restore(flags);
 405}
 406EXPORT_SYMBOL(inc_zone_page_state);
 407
 408void dec_zone_page_state(struct page *page, enum zone_stat_item item)
 409{
 410        unsigned long flags;
 411
 412        local_irq_save(flags);
 413        __dec_zone_page_state(page, item);
 414        local_irq_restore(flags);
 415}
 416EXPORT_SYMBOL(dec_zone_page_state);
 417#endif
 418
 419/*
 420 * Update the zone counters for one cpu.
 421 *
 422 * The cpu specified must be either the current cpu or a processor that
 423 * is not online. If it is the current cpu then the execution thread must
 424 * be pinned to the current cpu.
 425 *
 426 * Note that refresh_cpu_vm_stats strives to only access
 427 * node local memory. The per cpu pagesets on remote zones are placed
 428 * in the memory local to the processor using that pageset. So the
 429 * loop over all zones will access a series of cachelines local to
 430 * the processor.
 431 *
 432 * The call to zone_page_state_add updates the cachelines with the
 433 * statistics in the remote zone struct as well as the global cachelines
 434 * with the global counters. These could cause remote node cache line
 435 * bouncing and will have to be only done when necessary.
 436 */
 437void refresh_cpu_vm_stats(int cpu)
 438{
 439        struct zone *zone;
 440        int i;
 441        int global_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
 442
 443        for_each_populated_zone(zone) {
 444                struct per_cpu_pageset *p;
 445
 446                p = per_cpu_ptr(zone->pageset, cpu);
 447
 448                for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 449                        if (p->vm_stat_diff[i]) {
 450                                unsigned long flags;
 451                                int v;
 452
 453                                local_irq_save(flags);
 454                                v = p->vm_stat_diff[i];
 455                                p->vm_stat_diff[i] = 0;
 456                                local_irq_restore(flags);
 457                                atomic_long_add(v, &zone->vm_stat[i]);
 458                                global_diff[i] += v;
 459#ifdef CONFIG_NUMA
 460                                /* 3 seconds idle till flush */
 461                                p->expire = 3;
 462#endif
 463                        }
 464                cond_resched();
 465#ifdef CONFIG_NUMA
 466                /*
 467                 * Deal with draining the remote pageset of this
 468                 * processor
 469                 *
 470                 * Check if there are pages remaining in this pageset
 471                 * if not then there is nothing to expire.
 472                 */
 473                if (!p->expire || !p->pcp.count)
 474                        continue;
 475
 476                /*
 477                 * We never drain zones local to this processor.
 478                 */
 479                if (zone_to_nid(zone) == numa_node_id()) {
 480                        p->expire = 0;
 481                        continue;
 482                }
 483
 484                p->expire--;
 485                if (p->expire)
 486                        continue;
 487
 488                if (p->pcp.count)
 489                        drain_zone_pages(zone, &p->pcp);
 490#endif
 491        }
 492
 493        for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 494                if (global_diff[i])
 495                        atomic_long_add(global_diff[i], &vm_stat[i]);
 496}
 497
 498#endif
 499
 500#ifdef CONFIG_NUMA
 501/*
 502 * zonelist = the list of zones passed to the allocator
 503 * z        = the zone from which the allocation occurred.
 504 *
 505 * Must be called with interrupts disabled.
 506 *
 507 * When __GFP_OTHER_NODE is set assume the node of the preferred
 508 * zone is the local node. This is useful for daemons who allocate
 509 * memory on behalf of other processes.
 510 */
 511void zone_statistics(struct zone *preferred_zone, struct zone *z, gfp_t flags)
 512{
 513        if (z->zone_pgdat == preferred_zone->zone_pgdat) {
 514                __inc_zone_state(z, NUMA_HIT);
 515        } else {
 516                __inc_zone_state(z, NUMA_MISS);
 517                __inc_zone_state(preferred_zone, NUMA_FOREIGN);
 518        }
 519        if (z->node == ((flags & __GFP_OTHER_NODE) ?
 520                        preferred_zone->node : numa_node_id()))
 521                __inc_zone_state(z, NUMA_LOCAL);
 522        else
 523                __inc_zone_state(z, NUMA_OTHER);
 524}
 525#endif
 526
 527#ifdef CONFIG_COMPACTION
 528
 529struct contig_page_info {
 530        unsigned long free_pages;
 531        unsigned long free_blocks_total;
 532        unsigned long free_blocks_suitable;
 533};
 534
 535/*
 536 * Calculate the number of free pages in a zone, how many contiguous
 537 * pages are free and how many are large enough to satisfy an allocation of
 538 * the target size. Note that this function makes no attempt to estimate
 539 * how many suitable free blocks there *might* be if MOVABLE pages were
 540 * migrated. Calculating that is possible, but expensive and can be
 541 * figured out from userspace
 542 */
 543static void fill_contig_page_info(struct zone *zone,
 544                                unsigned int suitable_order,
 545                                struct contig_page_info *info)
 546{
 547        unsigned int order;
 548
 549        info->free_pages = 0;
 550        info->free_blocks_total = 0;
 551        info->free_blocks_suitable = 0;
 552
 553        for (order = 0; order < MAX_ORDER; order++) {
 554                unsigned long blocks;
 555
 556                /* Count number of free blocks */
 557                blocks = zone->free_area[order].nr_free;
 558                info->free_blocks_total += blocks;
 559
 560                /* Count free base pages */
 561                info->free_pages += blocks << order;
 562
 563                /* Count the suitable free blocks */
 564                if (order >= suitable_order)
 565                        info->free_blocks_suitable += blocks <<
 566                                                (order - suitable_order);
 567        }
 568}
 569
 570/*
 571 * A fragmentation index only makes sense if an allocation of a requested
 572 * size would fail. If that is true, the fragmentation index indicates
 573 * whether external fragmentation or a lack of memory was the problem.
 574 * The value can be used to determine if page reclaim or compaction
 575 * should be used
 576 */
 577static int __fragmentation_index(unsigned int order, struct contig_page_info *info)
 578{
 579        unsigned long requested = 1UL << order;
 580
 581        if (!info->free_blocks_total)
 582                return 0;
 583
 584        /* Fragmentation index only makes sense when a request would fail */
 585        if (info->free_blocks_suitable)
 586                return -1000;
 587
 588        /*
 589         * Index is between 0 and 1 so return within 3 decimal places
 590         *
 591         * 0 => allocation would fail due to lack of memory
 592         * 1 => allocation would fail due to fragmentation
 593         */
 594        return 1000 - div_u64( (1000+(div_u64(info->free_pages * 1000ULL, requested))), info->free_blocks_total);
 595}
 596
 597/* Same as __fragmentation index but allocs contig_page_info on stack */
 598int fragmentation_index(struct zone *zone, unsigned int order)
 599{
 600        struct contig_page_info info;
 601
 602        fill_contig_page_info(zone, order, &info);
 603        return __fragmentation_index(order, &info);
 604}
 605#endif
 606
 607#if defined(CONFIG_PROC_FS) || defined(CONFIG_COMPACTION)
 608#include <linux/proc_fs.h>
 609#include <linux/seq_file.h>
 610
 611static char * const migratetype_names[MIGRATE_TYPES] = {
 612        "Unmovable",
 613        "Reclaimable",
 614        "Movable",
 615        "Reserve",
 616        "Isolate",
 617};
 618
 619static void *frag_start(struct seq_file *m, loff_t *pos)
 620{
 621        pg_data_t *pgdat;
 622        loff_t node = *pos;
 623        for (pgdat = first_online_pgdat();
 624             pgdat && node;
 625             pgdat = next_online_pgdat(pgdat))
 626                --node;
 627
 628        return pgdat;
 629}
 630
 631static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
 632{
 633        pg_data_t *pgdat = (pg_data_t *)arg;
 634
 635        (*pos)++;
 636        return next_online_pgdat(pgdat);
 637}
 638
 639static void frag_stop(struct seq_file *m, void *arg)
 640{
 641}
 642
 643/* Walk all the zones in a node and print using a callback */
 644static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat,
 645                void (*print)(struct seq_file *m, pg_data_t *, struct zone *))
 646{
 647        struct zone *zone;
 648        struct zone *node_zones = pgdat->node_zones;
 649        unsigned long flags;
 650
 651        for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
 652                if (!populated_zone(zone))
 653                        continue;
 654
 655                spin_lock_irqsave(&zone->lock, flags);
 656                print(m, pgdat, zone);
 657                spin_unlock_irqrestore(&zone->lock, flags);
 658        }
 659}
 660#endif
 661
 662#if defined(CONFIG_PROC_FS) || defined(CONFIG_SYSFS) || defined(CONFIG_NUMA)
 663#ifdef CONFIG_ZONE_DMA
 664#define TEXT_FOR_DMA(xx) xx "_dma",
 665#else
 666#define TEXT_FOR_DMA(xx)
 667#endif
 668
 669#ifdef CONFIG_ZONE_DMA32
 670#define TEXT_FOR_DMA32(xx) xx "_dma32",
 671#else
 672#define TEXT_FOR_DMA32(xx)
 673#endif
 674
 675#ifdef CONFIG_HIGHMEM
 676#define TEXT_FOR_HIGHMEM(xx) xx "_high",
 677#else
 678#define TEXT_FOR_HIGHMEM(xx)
 679#endif
 680
 681#define TEXTS_FOR_ZONES(xx) TEXT_FOR_DMA(xx) TEXT_FOR_DMA32(xx) xx "_normal", \
 682                                        TEXT_FOR_HIGHMEM(xx) xx "_movable",
 683
 684const char * const vmstat_text[] = {
 685        /* Zoned VM counters */
 686        "nr_free_pages",
 687        "nr_inactive_anon",
 688        "nr_active_anon",
 689        "nr_inactive_file",
 690        "nr_active_file",
 691        "nr_unevictable",
 692        "nr_mlock",
 693        "nr_anon_pages",
 694        "nr_mapped",
 695        "nr_file_pages",
 696        "nr_dirty",
 697        "nr_writeback",
 698        "nr_slab_reclaimable",
 699        "nr_slab_unreclaimable",
 700        "nr_page_table_pages",
 701        "nr_kernel_stack",
 702        "nr_unstable",
 703        "nr_bounce",
 704        "nr_vmscan_write",
 705        "nr_writeback_temp",
 706        "nr_isolated_anon",
 707        "nr_isolated_file",
 708        "nr_shmem",
 709        "nr_dirtied",
 710        "nr_written",
 711
 712#ifdef CONFIG_NUMA
 713        "numa_hit",
 714        "numa_miss",
 715        "numa_foreign",
 716        "numa_interleave",
 717        "numa_local",
 718        "numa_other",
 719#endif
 720        "nr_anon_transparent_hugepages",
 721        "nr_dirty_threshold",
 722        "nr_dirty_background_threshold",
 723
 724#ifdef CONFIG_VM_EVENT_COUNTERS
 725        "pgpgin",
 726        "pgpgout",
 727        "pswpin",
 728        "pswpout",
 729
 730        TEXTS_FOR_ZONES("pgalloc")
 731
 732        "pgfree",
 733        "pgactivate",
 734        "pgdeactivate",
 735
 736        "pgfault",
 737        "pgmajfault",
 738
 739        TEXTS_FOR_ZONES("pgrefill")
 740        TEXTS_FOR_ZONES("pgsteal")
 741        TEXTS_FOR_ZONES("pgscan_kswapd")
 742        TEXTS_FOR_ZONES("pgscan_direct")
 743
 744#ifdef CONFIG_NUMA
 745        "zone_reclaim_failed",
 746#endif
 747        "pginodesteal",
 748        "slabs_scanned",
 749        "kswapd_steal",
 750        "kswapd_inodesteal",
 751        "kswapd_low_wmark_hit_quickly",
 752        "kswapd_high_wmark_hit_quickly",
 753        "kswapd_skip_congestion_wait",
 754        "pageoutrun",
 755        "allocstall",
 756
 757        "pgrotated",
 758
 759#ifdef CONFIG_COMPACTION
 760        "compact_blocks_moved",
 761        "compact_pages_moved",
 762        "compact_pagemigrate_failed",
 763        "compact_stall",
 764        "compact_fail",
 765        "compact_success",
 766#endif
 767
 768#ifdef CONFIG_HUGETLB_PAGE
 769        "htlb_buddy_alloc_success",
 770        "htlb_buddy_alloc_fail",
 771#endif
 772        "unevictable_pgs_culled",
 773        "unevictable_pgs_scanned",
 774        "unevictable_pgs_rescued",
 775        "unevictable_pgs_mlocked",
 776        "unevictable_pgs_munlocked",
 777        "unevictable_pgs_cleared",
 778        "unevictable_pgs_stranded",
 779        "unevictable_pgs_mlockfreed",
 780
 781#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 782        "thp_fault_alloc",
 783        "thp_fault_fallback",
 784        "thp_collapse_alloc",
 785        "thp_collapse_alloc_failed",
 786        "thp_split",
 787#endif
 788
 789#endif /* CONFIG_VM_EVENTS_COUNTERS */
 790};
 791#endif /* CONFIG_PROC_FS || CONFIG_SYSFS || CONFIG_NUMA */
 792
 793
 794#ifdef CONFIG_PROC_FS
 795static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,
 796                                                struct zone *zone)
 797{
 798        int order;
 799
 800        seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
 801        for (order = 0; order < MAX_ORDER; ++order)
 802                seq_printf(m, "%6lu ", zone->free_area[order].nr_free);
 803        seq_putc(m, '\n');
 804}
 805
 806/*
 807 * This walks the free areas for each zone.
 808 */
 809static int frag_show(struct seq_file *m, void *arg)
 810{
 811        pg_data_t *pgdat = (pg_data_t *)arg;
 812        walk_zones_in_node(m, pgdat, frag_show_print);
 813        return 0;
 814}
 815
 816static void pagetypeinfo_showfree_print(struct seq_file *m,
 817                                        pg_data_t *pgdat, struct zone *zone)
 818{
 819        int order, mtype;
 820
 821        for (mtype = 0; mtype < MIGRATE_TYPES; mtype++) {
 822                seq_printf(m, "Node %4d, zone %8s, type %12s ",
 823                                        pgdat->node_id,
 824                                        zone->name,
 825                                        migratetype_names[mtype]);
 826                for (order = 0; order < MAX_ORDER; ++order) {
 827                        unsigned long freecount = 0;
 828                        struct free_area *area;
 829                        struct list_head *curr;
 830
 831                        area = &(zone->free_area[order]);
 832
 833                        list_for_each(curr, &area->free_list[mtype])
 834                                freecount++;
 835                        seq_printf(m, "%6lu ", freecount);
 836                }
 837                seq_putc(m, '\n');
 838        }
 839}
 840
 841/* Print out the free pages at each order for each migatetype */
 842static int pagetypeinfo_showfree(struct seq_file *m, void *arg)
 843{
 844        int order;
 845        pg_data_t *pgdat = (pg_data_t *)arg;
 846
 847        /* Print header */
 848        seq_printf(m, "%-43s ", "Free pages count per migrate type at order");
 849        for (order = 0; order < MAX_ORDER; ++order)
 850                seq_printf(m, "%6d ", order);
 851        seq_putc(m, '\n');
 852
 853        walk_zones_in_node(m, pgdat, pagetypeinfo_showfree_print);
 854
 855        return 0;
 856}
 857
 858static void pagetypeinfo_showblockcount_print(struct seq_file *m,
 859                                        pg_data_t *pgdat, struct zone *zone)
 860{
 861        int mtype;
 862        unsigned long pfn;
 863        unsigned long start_pfn = zone->zone_start_pfn;
 864        unsigned long end_pfn = start_pfn + zone->spanned_pages;
 865        unsigned long count[MIGRATE_TYPES] = { 0, };
 866
 867        for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
 868                struct page *page;
 869
 870                if (!pfn_valid(pfn))
 871                        continue;
 872
 873                page = pfn_to_page(pfn);
 874
 875                /* Watch for unexpected holes punched in the memmap */
 876                if (!memmap_valid_within(pfn, page, zone))
 877                        continue;
 878
 879                mtype = get_pageblock_migratetype(page);
 880
 881                if (mtype < MIGRATE_TYPES)
 882                        count[mtype]++;
 883        }
 884
 885        /* Print counts */
 886        seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
 887        for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
 888                seq_printf(m, "%12lu ", count[mtype]);
 889        seq_putc(m, '\n');
 890}
 891
 892/* Print out the free pages at each order for each migratetype */
 893static int pagetypeinfo_showblockcount(struct seq_file *m, void *arg)
 894{
 895        int mtype;
 896        pg_data_t *pgdat = (pg_data_t *)arg;
 897
 898        seq_printf(m, "\n%-23s", "Number of blocks type ");
 899        for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
 900                seq_printf(m, "%12s ", migratetype_names[mtype]);
 901        seq_putc(m, '\n');
 902        walk_zones_in_node(m, pgdat, pagetypeinfo_showblockcount_print);
 903
 904        return 0;
 905}
 906
 907/*
 908 * This prints out statistics in relation to grouping pages by mobility.
 909 * It is expensive to collect so do not constantly read the file.
 910 */
 911static int pagetypeinfo_show(struct seq_file *m, void *arg)
 912{
 913        pg_data_t *pgdat = (pg_data_t *)arg;
 914
 915        /* check memoryless node */
 916        if (!node_state(pgdat->node_id, N_HIGH_MEMORY))
 917                return 0;
 918
 919        seq_printf(m, "Page block order: %d\n", pageblock_order);
 920        seq_printf(m, "Pages per block:  %lu\n", pageblock_nr_pages);
 921        seq_putc(m, '\n');
 922        pagetypeinfo_showfree(m, pgdat);
 923        pagetypeinfo_showblockcount(m, pgdat);
 924
 925        return 0;
 926}
 927
 928static const struct seq_operations fragmentation_op = {
 929        .start  = frag_start,
 930        .next   = frag_next,
 931        .stop   = frag_stop,
 932        .show   = frag_show,
 933};
 934
 935static int fragmentation_open(struct inode *inode, struct file *file)
 936{
 937        return seq_open(file, &fragmentation_op);
 938}
 939
 940static const struct file_operations fragmentation_file_operations = {
 941        .open           = fragmentation_open,
 942        .read           = seq_read,
 943        .llseek         = seq_lseek,
 944        .release        = seq_release,
 945};
 946
 947static const struct seq_operations pagetypeinfo_op = {
 948        .start  = frag_start,
 949        .next   = frag_next,
 950        .stop   = frag_stop,
 951        .show   = pagetypeinfo_show,
 952};
 953
 954static int pagetypeinfo_open(struct inode *inode, struct file *file)
 955{
 956        return seq_open(file, &pagetypeinfo_op);
 957}
 958
 959static const struct file_operations pagetypeinfo_file_ops = {
 960        .open           = pagetypeinfo_open,
 961        .read           = seq_read,
 962        .llseek         = seq_lseek,
 963        .release        = seq_release,
 964};
 965
 966static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
 967                                                        struct zone *zone)
 968{
 969        int i;
 970        seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name);
 971        seq_printf(m,
 972                   "\n  pages free     %lu"
 973                   "\n        min      %lu"
 974                   "\n        low      %lu"
 975                   "\n        high     %lu"
 976                   "\n        scanned  %lu"
 977                   "\n        spanned  %lu"
 978                   "\n        present  %lu",
 979                   zone_page_state(zone, NR_FREE_PAGES),
 980                   min_wmark_pages(zone),
 981                   low_wmark_pages(zone),
 982                   high_wmark_pages(zone),
 983                   zone->pages_scanned,
 984                   zone->spanned_pages,
 985                   zone->present_pages);
 986
 987        for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
 988                seq_printf(m, "\n    %-12s %lu", vmstat_text[i],
 989                                zone_page_state(zone, i));
 990
 991        seq_printf(m,
 992                   "\n        protection: (%lu",
 993                   zone->lowmem_reserve[0]);
 994        for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++)
 995                seq_printf(m, ", %lu", zone->lowmem_reserve[i]);
 996        seq_printf(m,
 997                   ")"
 998                   "\n  pagesets");
 999        for_each_online_cpu(i) {
1000                struct per_cpu_pageset *pageset;
1001
1002                pageset = per_cpu_ptr(zone->pageset, i);
1003                seq_printf(m,
1004                           "\n    cpu: %i"
1005                           "\n              count: %i"
1006                           "\n              high:  %i"
1007                           "\n              batch: %i",
1008                           i,
1009                           pageset->pcp.count,
1010                           pageset->pcp.high,
1011                           pageset->pcp.batch);
1012#ifdef CONFIG_SMP
1013                seq_printf(m, "\n  vm stats threshold: %d",
1014                                pageset->stat_threshold);
1015#endif
1016        }
1017        seq_printf(m,
1018                   "\n  all_unreclaimable: %u"
1019                   "\n  start_pfn:         %lu"
1020                   "\n  inactive_ratio:    %u",
1021                   zone->all_unreclaimable,
1022                   zone->zone_start_pfn,
1023                   zone->inactive_ratio);
1024        seq_putc(m, '\n');
1025}
1026
1027/*
1028 * Output information about zones in @pgdat.
1029 */
1030static int zoneinfo_show(struct seq_file *m, void *arg)
1031{
1032        pg_data_t *pgdat = (pg_data_t *)arg;
1033        walk_zones_in_node(m, pgdat, zoneinfo_show_print);
1034        return 0;
1035}
1036
1037static const struct seq_operations zoneinfo_op = {
1038        .start  = frag_start, /* iterate over all zones. The same as in
1039                               * fragmentation. */
1040        .next   = frag_next,
1041        .stop   = frag_stop,
1042        .show   = zoneinfo_show,
1043};
1044
1045static int zoneinfo_open(struct inode *inode, struct file *file)
1046{
1047        return seq_open(file, &zoneinfo_op);
1048}
1049
1050static const struct file_operations proc_zoneinfo_file_operations = {
1051        .open           = zoneinfo_open,
1052        .read           = seq_read,
1053        .llseek         = seq_lseek,
1054        .release        = seq_release,
1055};
1056
1057enum writeback_stat_item {
1058        NR_DIRTY_THRESHOLD,
1059        NR_DIRTY_BG_THRESHOLD,
1060        NR_VM_WRITEBACK_STAT_ITEMS,
1061};
1062
1063static void *vmstat_start(struct seq_file *m, loff_t *pos)
1064{
1065        unsigned long *v;
1066        int i, stat_items_size;
1067
1068        if (*pos >= ARRAY_SIZE(vmstat_text))
1069                return NULL;
1070        stat_items_size = NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long) +
1071                          NR_VM_WRITEBACK_STAT_ITEMS * sizeof(unsigned long);
1072
1073#ifdef CONFIG_VM_EVENT_COUNTERS
1074        stat_items_size += sizeof(struct vm_event_state);
1075#endif
1076
1077        v = kmalloc(stat_items_size, GFP_KERNEL);
1078        m->private = v;
1079        if (!v)
1080                return ERR_PTR(-ENOMEM);
1081        for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
1082                v[i] = global_page_state(i);
1083        v += NR_VM_ZONE_STAT_ITEMS;
1084
1085        global_dirty_limits(v + NR_DIRTY_BG_THRESHOLD,
1086                            v + NR_DIRTY_THRESHOLD);
1087        v += NR_VM_WRITEBACK_STAT_ITEMS;
1088
1089#ifdef CONFIG_VM_EVENT_COUNTERS
1090        all_vm_events(v);
1091        v[PGPGIN] /= 2;         /* sectors -> kbytes */
1092        v[PGPGOUT] /= 2;
1093#endif
1094        return (unsigned long *)m->private + *pos;
1095}
1096
1097static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)
1098{
1099        (*pos)++;
1100        if (*pos >= ARRAY_SIZE(vmstat_text))
1101                return NULL;
1102        return (unsigned long *)m->private + *pos;
1103}
1104
1105static int vmstat_show(struct seq_file *m, void *arg)
1106{
1107        unsigned long *l = arg;
1108        unsigned long off = l - (unsigned long *)m->private;
1109
1110        seq_printf(m, "%s %lu\n", vmstat_text[off], *l);
1111        return 0;
1112}
1113
1114static void vmstat_stop(struct seq_file *m, void *arg)
1115{
1116        kfree(m->private);
1117        m->private = NULL;
1118}
1119
1120static const struct seq_operations vmstat_op = {
1121        .start  = vmstat_start,
1122        .next   = vmstat_next,
1123        .stop   = vmstat_stop,
1124        .show   = vmstat_show,
1125};
1126
1127static int vmstat_open(struct inode *inode, struct file *file)
1128{
1129        return seq_open(file, &vmstat_op);
1130}
1131
1132static const struct file_operations proc_vmstat_file_operations = {
1133        .open           = vmstat_open,
1134        .read           = seq_read,
1135        .llseek         = seq_lseek,
1136        .release        = seq_release,
1137};
1138#endif /* CONFIG_PROC_FS */
1139
1140#ifdef CONFIG_SMP
1141static DEFINE_PER_CPU(struct delayed_work, vmstat_work);
1142int sysctl_stat_interval __read_mostly = HZ;
1143
1144static void vmstat_update(struct work_struct *w)
1145{
1146        refresh_cpu_vm_stats(smp_processor_id());
1147        schedule_delayed_work(&__get_cpu_var(vmstat_work),
1148                round_jiffies_relative(sysctl_stat_interval));
1149}
1150
1151static void __cpuinit start_cpu_timer(int cpu)
1152{
1153        struct delayed_work *work = &per_cpu(vmstat_work, cpu);
1154
1155        INIT_DELAYED_WORK_DEFERRABLE(work, vmstat_update);
1156        schedule_delayed_work_on(cpu, work, __round_jiffies_relative(HZ, cpu));
1157}
1158
1159/*
1160 * Use the cpu notifier to insure that the thresholds are recalculated
1161 * when necessary.
1162 */
1163static int __cpuinit vmstat_cpuup_callback(struct notifier_block *nfb,
1164                unsigned long action,
1165                void *hcpu)
1166{
1167        long cpu = (long)hcpu;
1168
1169        switch (action) {
1170        case CPU_ONLINE:
1171        case CPU_ONLINE_FROZEN:
1172                refresh_zone_stat_thresholds();
1173                start_cpu_timer(cpu);
1174                node_set_state(cpu_to_node(cpu), N_CPU);
1175                break;
1176        case CPU_DOWN_PREPARE:
1177        case CPU_DOWN_PREPARE_FROZEN:
1178                cancel_delayed_work_sync(&per_cpu(vmstat_work, cpu));
1179                per_cpu(vmstat_work, cpu).work.func = NULL;
1180                break;
1181        case CPU_DOWN_FAILED:
1182        case CPU_DOWN_FAILED_FROZEN:
1183                start_cpu_timer(cpu);
1184                break;
1185        case CPU_DEAD:
1186        case CPU_DEAD_FROZEN:
1187                refresh_zone_stat_thresholds();
1188                break;
1189        default:
1190                break;
1191        }
1192        return NOTIFY_OK;
1193}
1194
1195static struct notifier_block __cpuinitdata vmstat_notifier =
1196        { &vmstat_cpuup_callback, NULL, 0 };
1197#endif
1198
1199static int __init setup_vmstat(void)
1200{
1201#ifdef CONFIG_SMP
1202        int cpu;
1203
1204        register_cpu_notifier(&vmstat_notifier);
1205
1206        for_each_online_cpu(cpu)
1207                start_cpu_timer(cpu);
1208#endif
1209#ifdef CONFIG_PROC_FS
1210        proc_create("buddyinfo", S_IRUGO, NULL, &fragmentation_file_operations);
1211        proc_create("pagetypeinfo", S_IRUGO, NULL, &pagetypeinfo_file_ops);
1212        proc_create("vmstat", S_IRUGO, NULL, &proc_vmstat_file_operations);
1213        proc_create("zoneinfo", S_IRUGO, NULL, &proc_zoneinfo_file_operations);
1214#endif
1215        return 0;
1216}
1217module_init(setup_vmstat)
1218
1219#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)
1220#include <linux/debugfs.h>
1221
1222static struct dentry *extfrag_debug_root;
1223
1224/*
1225 * Return an index indicating how much of the available free memory is
1226 * unusable for an allocation of the requested size.
1227 */
1228static int unusable_free_index(unsigned int order,
1229                                struct contig_page_info *info)
1230{
1231        /* No free memory is interpreted as all free memory is unusable */
1232        if (info->free_pages == 0)
1233                return 1000;
1234
1235        /*
1236         * Index should be a value between 0 and 1. Return a value to 3
1237         * decimal places.
1238         *
1239         * 0 => no fragmentation
1240         * 1 => high fragmentation
1241         */
1242        return div_u64((info->free_pages - (info->free_blocks_suitable << order)) * 1000ULL, info->free_pages);
1243
1244}
1245
1246static void unusable_show_print(struct seq_file *m,
1247                                        pg_data_t *pgdat, struct zone *zone)
1248{
1249        unsigned int order;
1250        int index;
1251        struct contig_page_info info;
1252
1253        seq_printf(m, "Node %d, zone %8s ",
1254                                pgdat->node_id,
1255                                zone->name);
1256        for (order = 0; order < MAX_ORDER; ++order) {
1257                fill_contig_page_info(zone, order, &info);
1258                index = unusable_free_index(order, &info);
1259                seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
1260        }
1261
1262        seq_putc(m, '\n');
1263}
1264
1265/*
1266 * Display unusable free space index
1267 *
1268 * The unusable free space index measures how much of the available free
1269 * memory cannot be used to satisfy an allocation of a given size and is a
1270 * value between 0 and 1. The higher the value, the more of free memory is
1271 * unusable and by implication, the worse the external fragmentation is. This
1272 * can be expressed as a percentage by multiplying by 100.
1273 */
1274static int unusable_show(struct seq_file *m, void *arg)
1275{
1276        pg_data_t *pgdat = (pg_data_t *)arg;
1277
1278        /* check memoryless node */
1279        if (!node_state(pgdat->node_id, N_HIGH_MEMORY))
1280                return 0;
1281
1282        walk_zones_in_node(m, pgdat, unusable_show_print);
1283
1284        return 0;
1285}
1286
1287static const struct seq_operations unusable_op = {
1288        .start  = frag_start,
1289        .next   = frag_next,
1290        .stop   = frag_stop,
1291        .show   = unusable_show,
1292};
1293
1294static int unusable_open(struct inode *inode, struct file *file)
1295{
1296        return seq_open(file, &unusable_op);
1297}
1298
1299static const struct file_operations unusable_file_ops = {
1300        .open           = unusable_open,
1301        .read           = seq_read,
1302        .llseek         = seq_lseek,
1303        .release        = seq_release,
1304};
1305
1306static void extfrag_show_print(struct seq_file *m,
1307                                        pg_data_t *pgdat, struct zone *zone)
1308{
1309        unsigned int order;
1310        int index;
1311
1312        /* Alloc on stack as interrupts are disabled for zone walk */
1313        struct contig_page_info info;
1314
1315        seq_printf(m, "Node %d, zone %8s ",
1316                                pgdat->node_id,
1317                                zone->name);
1318        for (order = 0; order < MAX_ORDER; ++order) {
1319                fill_contig_page_info(zone, order, &info);
1320                index = __fragmentation_index(order, &info);
1321                seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
1322        }
1323
1324        seq_putc(m, '\n');
1325}
1326
1327/*
1328 * Display fragmentation index for orders that allocations would fail for
1329 */
1330static int extfrag_show(struct seq_file *m, void *arg)
1331{
1332        pg_data_t *pgdat = (pg_data_t *)arg;
1333
1334        walk_zones_in_node(m, pgdat, extfrag_show_print);
1335
1336        return 0;
1337}
1338
1339static const struct seq_operations extfrag_op = {
1340        .start  = frag_start,
1341        .next   = frag_next,
1342        .stop   = frag_stop,
1343        .show   = extfrag_show,
1344};
1345
1346static int extfrag_open(struct inode *inode, struct file *file)
1347{
1348        return seq_open(file, &extfrag_op);
1349}
1350
1351static const struct file_operations extfrag_file_ops = {
1352        .open           = extfrag_open,
1353        .read           = seq_read,
1354        .llseek         = seq_lseek,
1355        .release        = seq_release,
1356};
1357
1358static int __init extfrag_debug_init(void)
1359{
1360        extfrag_debug_root = debugfs_create_dir("extfrag", NULL);
1361        if (!extfrag_debug_root)
1362                return -ENOMEM;
1363
1364        if (!debugfs_create_file("unusable_index", 0444,
1365                        extfrag_debug_root, NULL, &unusable_file_ops))
1366                return -ENOMEM;
1367
1368        if (!debugfs_create_file("extfrag_index", 0444,
1369                        extfrag_debug_root, NULL, &extfrag_file_ops))
1370                return -ENOMEM;
1371
1372        return 0;
1373}
1374
1375module_init(extfrag_debug_init);
1376#endif
1377
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.