Root/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#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)
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 */
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

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