mm: workingset: tell cache transitions from workingset thrashing
[muen/linux.git] / 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  *  Copyright (C) 2008-2014 Christoph Lameter
11  */
12 #include <linux/fs.h>
13 #include <linux/mm.h>
14 #include <linux/err.h>
15 #include <linux/module.h>
16 #include <linux/slab.h>
17 #include <linux/cpu.h>
18 #include <linux/cpumask.h>
19 #include <linux/vmstat.h>
20 #include <linux/proc_fs.h>
21 #include <linux/seq_file.h>
22 #include <linux/debugfs.h>
23 #include <linux/sched.h>
24 #include <linux/math64.h>
25 #include <linux/writeback.h>
26 #include <linux/compaction.h>
27 #include <linux/mm_inline.h>
28 #include <linux/page_ext.h>
29 #include <linux/page_owner.h>
30
31 #include "internal.h"
32
33 #define NUMA_STATS_THRESHOLD (U16_MAX - 2)
34
35 #ifdef CONFIG_NUMA
36 int sysctl_vm_numa_stat = ENABLE_NUMA_STAT;
37
38 /* zero numa counters within a zone */
39 static void zero_zone_numa_counters(struct zone *zone)
40 {
41         int item, cpu;
42
43         for (item = 0; item < NR_VM_NUMA_STAT_ITEMS; item++) {
44                 atomic_long_set(&zone->vm_numa_stat[item], 0);
45                 for_each_online_cpu(cpu)
46                         per_cpu_ptr(zone->pageset, cpu)->vm_numa_stat_diff[item]
47                                                 = 0;
48         }
49 }
50
51 /* zero numa counters of all the populated zones */
52 static void zero_zones_numa_counters(void)
53 {
54         struct zone *zone;
55
56         for_each_populated_zone(zone)
57                 zero_zone_numa_counters(zone);
58 }
59
60 /* zero global numa counters */
61 static void zero_global_numa_counters(void)
62 {
63         int item;
64
65         for (item = 0; item < NR_VM_NUMA_STAT_ITEMS; item++)
66                 atomic_long_set(&vm_numa_stat[item], 0);
67 }
68
69 static void invalid_numa_statistics(void)
70 {
71         zero_zones_numa_counters();
72         zero_global_numa_counters();
73 }
74
75 static DEFINE_MUTEX(vm_numa_stat_lock);
76
77 int sysctl_vm_numa_stat_handler(struct ctl_table *table, int write,
78                 void __user *buffer, size_t *length, loff_t *ppos)
79 {
80         int ret, oldval;
81
82         mutex_lock(&vm_numa_stat_lock);
83         if (write)
84                 oldval = sysctl_vm_numa_stat;
85         ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
86         if (ret || !write)
87                 goto out;
88
89         if (oldval == sysctl_vm_numa_stat)
90                 goto out;
91         else if (sysctl_vm_numa_stat == ENABLE_NUMA_STAT) {
92                 static_branch_enable(&vm_numa_stat_key);
93                 pr_info("enable numa statistics\n");
94         } else {
95                 static_branch_disable(&vm_numa_stat_key);
96                 invalid_numa_statistics();
97                 pr_info("disable numa statistics, and clear numa counters\n");
98         }
99
100 out:
101         mutex_unlock(&vm_numa_stat_lock);
102         return ret;
103 }
104 #endif
105
106 #ifdef CONFIG_VM_EVENT_COUNTERS
107 DEFINE_PER_CPU(struct vm_event_state, vm_event_states) = {{0}};
108 EXPORT_PER_CPU_SYMBOL(vm_event_states);
109
110 static void sum_vm_events(unsigned long *ret)
111 {
112         int cpu;
113         int i;
114
115         memset(ret, 0, NR_VM_EVENT_ITEMS * sizeof(unsigned long));
116
117         for_each_online_cpu(cpu) {
118                 struct vm_event_state *this = &per_cpu(vm_event_states, cpu);
119
120                 for (i = 0; i < NR_VM_EVENT_ITEMS; i++)
121                         ret[i] += this->event[i];
122         }
123 }
124
125 /*
126  * Accumulate the vm event counters across all CPUs.
127  * The result is unavoidably approximate - it can change
128  * during and after execution of this function.
129 */
130 void all_vm_events(unsigned long *ret)
131 {
132         get_online_cpus();
133         sum_vm_events(ret);
134         put_online_cpus();
135 }
136 EXPORT_SYMBOL_GPL(all_vm_events);
137
138 /*
139  * Fold the foreign cpu events into our own.
140  *
141  * This is adding to the events on one processor
142  * but keeps the global counts constant.
143  */
144 void vm_events_fold_cpu(int cpu)
145 {
146         struct vm_event_state *fold_state = &per_cpu(vm_event_states, cpu);
147         int i;
148
149         for (i = 0; i < NR_VM_EVENT_ITEMS; i++) {
150                 count_vm_events(i, fold_state->event[i]);
151                 fold_state->event[i] = 0;
152         }
153 }
154
155 #endif /* CONFIG_VM_EVENT_COUNTERS */
156
157 /*
158  * Manage combined zone based / global counters
159  *
160  * vm_stat contains the global counters
161  */
162 atomic_long_t vm_zone_stat[NR_VM_ZONE_STAT_ITEMS] __cacheline_aligned_in_smp;
163 atomic_long_t vm_numa_stat[NR_VM_NUMA_STAT_ITEMS] __cacheline_aligned_in_smp;
164 atomic_long_t vm_node_stat[NR_VM_NODE_STAT_ITEMS] __cacheline_aligned_in_smp;
165 EXPORT_SYMBOL(vm_zone_stat);
166 EXPORT_SYMBOL(vm_numa_stat);
167 EXPORT_SYMBOL(vm_node_stat);
168
169 #ifdef CONFIG_SMP
170
171 int calculate_pressure_threshold(struct zone *zone)
172 {
173         int threshold;
174         int watermark_distance;
175
176         /*
177          * As vmstats are not up to date, there is drift between the estimated
178          * and real values. For high thresholds and a high number of CPUs, it
179          * is possible for the min watermark to be breached while the estimated
180          * value looks fine. The pressure threshold is a reduced value such
181          * that even the maximum amount of drift will not accidentally breach
182          * the min watermark
183          */
184         watermark_distance = low_wmark_pages(zone) - min_wmark_pages(zone);
185         threshold = max(1, (int)(watermark_distance / num_online_cpus()));
186
187         /*
188          * Maximum threshold is 125
189          */
190         threshold = min(125, threshold);
191
192         return threshold;
193 }
194
195 int calculate_normal_threshold(struct zone *zone)
196 {
197         int threshold;
198         int mem;        /* memory in 128 MB units */
199
200         /*
201          * The threshold scales with the number of processors and the amount
202          * of memory per zone. More memory means that we can defer updates for
203          * longer, more processors could lead to more contention.
204          * fls() is used to have a cheap way of logarithmic scaling.
205          *
206          * Some sample thresholds:
207          *
208          * Threshold    Processors      (fls)   Zonesize        fls(mem+1)
209          * ------------------------------------------------------------------
210          * 8            1               1       0.9-1 GB        4
211          * 16           2               2       0.9-1 GB        4
212          * 20           2               2       1-2 GB          5
213          * 24           2               2       2-4 GB          6
214          * 28           2               2       4-8 GB          7
215          * 32           2               2       8-16 GB         8
216          * 4            2               2       <128M           1
217          * 30           4               3       2-4 GB          5
218          * 48           4               3       8-16 GB         8
219          * 32           8               4       1-2 GB          4
220          * 32           8               4       0.9-1GB         4
221          * 10           16              5       <128M           1
222          * 40           16              5       900M            4
223          * 70           64              7       2-4 GB          5
224          * 84           64              7       4-8 GB          6
225          * 108          512             9       4-8 GB          6
226          * 125          1024            10      8-16 GB         8
227          * 125          1024            10      16-32 GB        9
228          */
229
230         mem = zone->managed_pages >> (27 - PAGE_SHIFT);
231
232         threshold = 2 * fls(num_online_cpus()) * (1 + fls(mem));
233
234         /*
235          * Maximum threshold is 125
236          */
237         threshold = min(125, threshold);
238
239         return threshold;
240 }
241
242 /*
243  * Refresh the thresholds for each zone.
244  */
245 void refresh_zone_stat_thresholds(void)
246 {
247         struct pglist_data *pgdat;
248         struct zone *zone;
249         int cpu;
250         int threshold;
251
252         /* Zero current pgdat thresholds */
253         for_each_online_pgdat(pgdat) {
254                 for_each_online_cpu(cpu) {
255                         per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold = 0;
256                 }
257         }
258
259         for_each_populated_zone(zone) {
260                 struct pglist_data *pgdat = zone->zone_pgdat;
261                 unsigned long max_drift, tolerate_drift;
262
263                 threshold = calculate_normal_threshold(zone);
264
265                 for_each_online_cpu(cpu) {
266                         int pgdat_threshold;
267
268                         per_cpu_ptr(zone->pageset, cpu)->stat_threshold
269                                                         = threshold;
270
271                         /* Base nodestat threshold on the largest populated zone. */
272                         pgdat_threshold = per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold;
273                         per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold
274                                 = max(threshold, pgdat_threshold);
275                 }
276
277                 /*
278                  * Only set percpu_drift_mark if there is a danger that
279                  * NR_FREE_PAGES reports the low watermark is ok when in fact
280                  * the min watermark could be breached by an allocation
281                  */
282                 tolerate_drift = low_wmark_pages(zone) - min_wmark_pages(zone);
283                 max_drift = num_online_cpus() * threshold;
284                 if (max_drift > tolerate_drift)
285                         zone->percpu_drift_mark = high_wmark_pages(zone) +
286                                         max_drift;
287         }
288 }
289
290 void set_pgdat_percpu_threshold(pg_data_t *pgdat,
291                                 int (*calculate_pressure)(struct zone *))
292 {
293         struct zone *zone;
294         int cpu;
295         int threshold;
296         int i;
297
298         for (i = 0; i < pgdat->nr_zones; i++) {
299                 zone = &pgdat->node_zones[i];
300                 if (!zone->percpu_drift_mark)
301                         continue;
302
303                 threshold = (*calculate_pressure)(zone);
304                 for_each_online_cpu(cpu)
305                         per_cpu_ptr(zone->pageset, cpu)->stat_threshold
306                                                         = threshold;
307         }
308 }
309
310 /*
311  * For use when we know that interrupts are disabled,
312  * or when we know that preemption is disabled and that
313  * particular counter cannot be updated from interrupt context.
314  */
315 void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
316                            long delta)
317 {
318         struct per_cpu_pageset __percpu *pcp = zone->pageset;
319         s8 __percpu *p = pcp->vm_stat_diff + item;
320         long x;
321         long t;
322
323         x = delta + __this_cpu_read(*p);
324
325         t = __this_cpu_read(pcp->stat_threshold);
326
327         if (unlikely(x > t || x < -t)) {
328                 zone_page_state_add(x, zone, item);
329                 x = 0;
330         }
331         __this_cpu_write(*p, x);
332 }
333 EXPORT_SYMBOL(__mod_zone_page_state);
334
335 void __mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
336                                 long delta)
337 {
338         struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
339         s8 __percpu *p = pcp->vm_node_stat_diff + item;
340         long x;
341         long t;
342
343         x = delta + __this_cpu_read(*p);
344
345         t = __this_cpu_read(pcp->stat_threshold);
346
347         if (unlikely(x > t || x < -t)) {
348                 node_page_state_add(x, pgdat, item);
349                 x = 0;
350         }
351         __this_cpu_write(*p, x);
352 }
353 EXPORT_SYMBOL(__mod_node_page_state);
354
355 /*
356  * Optimized increment and decrement functions.
357  *
358  * These are only for a single page and therefore can take a struct page *
359  * argument instead of struct zone *. This allows the inclusion of the code
360  * generated for page_zone(page) into the optimized functions.
361  *
362  * No overflow check is necessary and therefore the differential can be
363  * incremented or decremented in place which may allow the compilers to
364  * generate better code.
365  * The increment or decrement is known and therefore one boundary check can
366  * be omitted.
367  *
368  * NOTE: These functions are very performance sensitive. Change only
369  * with care.
370  *
371  * Some processors have inc/dec instructions that are atomic vs an interrupt.
372  * However, the code must first determine the differential location in a zone
373  * based on the processor number and then inc/dec the counter. There is no
374  * guarantee without disabling preemption that the processor will not change
375  * in between and therefore the atomicity vs. interrupt cannot be exploited
376  * in a useful way here.
377  */
378 void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
379 {
380         struct per_cpu_pageset __percpu *pcp = zone->pageset;
381         s8 __percpu *p = pcp->vm_stat_diff + item;
382         s8 v, t;
383
384         v = __this_cpu_inc_return(*p);
385         t = __this_cpu_read(pcp->stat_threshold);
386         if (unlikely(v > t)) {
387                 s8 overstep = t >> 1;
388
389                 zone_page_state_add(v + overstep, zone, item);
390                 __this_cpu_write(*p, -overstep);
391         }
392 }
393
394 void __inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
395 {
396         struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
397         s8 __percpu *p = pcp->vm_node_stat_diff + item;
398         s8 v, t;
399
400         v = __this_cpu_inc_return(*p);
401         t = __this_cpu_read(pcp->stat_threshold);
402         if (unlikely(v > t)) {
403                 s8 overstep = t >> 1;
404
405                 node_page_state_add(v + overstep, pgdat, item);
406                 __this_cpu_write(*p, -overstep);
407         }
408 }
409
410 void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
411 {
412         __inc_zone_state(page_zone(page), item);
413 }
414 EXPORT_SYMBOL(__inc_zone_page_state);
415
416 void __inc_node_page_state(struct page *page, enum node_stat_item item)
417 {
418         __inc_node_state(page_pgdat(page), item);
419 }
420 EXPORT_SYMBOL(__inc_node_page_state);
421
422 void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
423 {
424         struct per_cpu_pageset __percpu *pcp = zone->pageset;
425         s8 __percpu *p = pcp->vm_stat_diff + item;
426         s8 v, t;
427
428         v = __this_cpu_dec_return(*p);
429         t = __this_cpu_read(pcp->stat_threshold);
430         if (unlikely(v < - t)) {
431                 s8 overstep = t >> 1;
432
433                 zone_page_state_add(v - overstep, zone, item);
434                 __this_cpu_write(*p, overstep);
435         }
436 }
437
438 void __dec_node_state(struct pglist_data *pgdat, enum node_stat_item item)
439 {
440         struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
441         s8 __percpu *p = pcp->vm_node_stat_diff + item;
442         s8 v, t;
443
444         v = __this_cpu_dec_return(*p);
445         t = __this_cpu_read(pcp->stat_threshold);
446         if (unlikely(v < - t)) {
447                 s8 overstep = t >> 1;
448
449                 node_page_state_add(v - overstep, pgdat, item);
450                 __this_cpu_write(*p, overstep);
451         }
452 }
453
454 void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
455 {
456         __dec_zone_state(page_zone(page), item);
457 }
458 EXPORT_SYMBOL(__dec_zone_page_state);
459
460 void __dec_node_page_state(struct page *page, enum node_stat_item item)
461 {
462         __dec_node_state(page_pgdat(page), item);
463 }
464 EXPORT_SYMBOL(__dec_node_page_state);
465
466 #ifdef CONFIG_HAVE_CMPXCHG_LOCAL
467 /*
468  * If we have cmpxchg_local support then we do not need to incur the overhead
469  * that comes with local_irq_save/restore if we use this_cpu_cmpxchg.
470  *
471  * mod_state() modifies the zone counter state through atomic per cpu
472  * operations.
473  *
474  * Overstep mode specifies how overstep should handled:
475  *     0       No overstepping
476  *     1       Overstepping half of threshold
477  *     -1      Overstepping minus half of threshold
478 */
479 static inline void mod_zone_state(struct zone *zone,
480        enum zone_stat_item item, long delta, int overstep_mode)
481 {
482         struct per_cpu_pageset __percpu *pcp = zone->pageset;
483         s8 __percpu *p = pcp->vm_stat_diff + item;
484         long o, n, t, z;
485
486         do {
487                 z = 0;  /* overflow to zone counters */
488
489                 /*
490                  * The fetching of the stat_threshold is racy. We may apply
491                  * a counter threshold to the wrong the cpu if we get
492                  * rescheduled while executing here. However, the next
493                  * counter update will apply the threshold again and
494                  * therefore bring the counter under the threshold again.
495                  *
496                  * Most of the time the thresholds are the same anyways
497                  * for all cpus in a zone.
498                  */
499                 t = this_cpu_read(pcp->stat_threshold);
500
501                 o = this_cpu_read(*p);
502                 n = delta + o;
503
504                 if (n > t || n < -t) {
505                         int os = overstep_mode * (t >> 1) ;
506
507                         /* Overflow must be added to zone counters */
508                         z = n + os;
509                         n = -os;
510                 }
511         } while (this_cpu_cmpxchg(*p, o, n) != o);
512
513         if (z)
514                 zone_page_state_add(z, zone, item);
515 }
516
517 void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
518                          long delta)
519 {
520         mod_zone_state(zone, item, delta, 0);
521 }
522 EXPORT_SYMBOL(mod_zone_page_state);
523
524 void inc_zone_page_state(struct page *page, enum zone_stat_item item)
525 {
526         mod_zone_state(page_zone(page), item, 1, 1);
527 }
528 EXPORT_SYMBOL(inc_zone_page_state);
529
530 void dec_zone_page_state(struct page *page, enum zone_stat_item item)
531 {
532         mod_zone_state(page_zone(page), item, -1, -1);
533 }
534 EXPORT_SYMBOL(dec_zone_page_state);
535
536 static inline void mod_node_state(struct pglist_data *pgdat,
537        enum node_stat_item item, int delta, int overstep_mode)
538 {
539         struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
540         s8 __percpu *p = pcp->vm_node_stat_diff + item;
541         long o, n, t, z;
542
543         do {
544                 z = 0;  /* overflow to node counters */
545
546                 /*
547                  * The fetching of the stat_threshold is racy. We may apply
548                  * a counter threshold to the wrong the cpu if we get
549                  * rescheduled while executing here. However, the next
550                  * counter update will apply the threshold again and
551                  * therefore bring the counter under the threshold again.
552                  *
553                  * Most of the time the thresholds are the same anyways
554                  * for all cpus in a node.
555                  */
556                 t = this_cpu_read(pcp->stat_threshold);
557
558                 o = this_cpu_read(*p);
559                 n = delta + o;
560
561                 if (n > t || n < -t) {
562                         int os = overstep_mode * (t >> 1) ;
563
564                         /* Overflow must be added to node counters */
565                         z = n + os;
566                         n = -os;
567                 }
568         } while (this_cpu_cmpxchg(*p, o, n) != o);
569
570         if (z)
571                 node_page_state_add(z, pgdat, item);
572 }
573
574 void mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
575                                         long delta)
576 {
577         mod_node_state(pgdat, item, delta, 0);
578 }
579 EXPORT_SYMBOL(mod_node_page_state);
580
581 void inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
582 {
583         mod_node_state(pgdat, item, 1, 1);
584 }
585
586 void inc_node_page_state(struct page *page, enum node_stat_item item)
587 {
588         mod_node_state(page_pgdat(page), item, 1, 1);
589 }
590 EXPORT_SYMBOL(inc_node_page_state);
591
592 void dec_node_page_state(struct page *page, enum node_stat_item item)
593 {
594         mod_node_state(page_pgdat(page), item, -1, -1);
595 }
596 EXPORT_SYMBOL(dec_node_page_state);
597 #else
598 /*
599  * Use interrupt disable to serialize counter updates
600  */
601 void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
602                          long delta)
603 {
604         unsigned long flags;
605
606         local_irq_save(flags);
607         __mod_zone_page_state(zone, item, delta);
608         local_irq_restore(flags);
609 }
610 EXPORT_SYMBOL(mod_zone_page_state);
611
612 void inc_zone_page_state(struct page *page, enum zone_stat_item item)
613 {
614         unsigned long flags;
615         struct zone *zone;
616
617         zone = page_zone(page);
618         local_irq_save(flags);
619         __inc_zone_state(zone, item);
620         local_irq_restore(flags);
621 }
622 EXPORT_SYMBOL(inc_zone_page_state);
623
624 void dec_zone_page_state(struct page *page, enum zone_stat_item item)
625 {
626         unsigned long flags;
627
628         local_irq_save(flags);
629         __dec_zone_page_state(page, item);
630         local_irq_restore(flags);
631 }
632 EXPORT_SYMBOL(dec_zone_page_state);
633
634 void inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
635 {
636         unsigned long flags;
637
638         local_irq_save(flags);
639         __inc_node_state(pgdat, item);
640         local_irq_restore(flags);
641 }
642 EXPORT_SYMBOL(inc_node_state);
643
644 void mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
645                                         long delta)
646 {
647         unsigned long flags;
648
649         local_irq_save(flags);
650         __mod_node_page_state(pgdat, item, delta);
651         local_irq_restore(flags);
652 }
653 EXPORT_SYMBOL(mod_node_page_state);
654
655 void inc_node_page_state(struct page *page, enum node_stat_item item)
656 {
657         unsigned long flags;
658         struct pglist_data *pgdat;
659
660         pgdat = page_pgdat(page);
661         local_irq_save(flags);
662         __inc_node_state(pgdat, item);
663         local_irq_restore(flags);
664 }
665 EXPORT_SYMBOL(inc_node_page_state);
666
667 void dec_node_page_state(struct page *page, enum node_stat_item item)
668 {
669         unsigned long flags;
670
671         local_irq_save(flags);
672         __dec_node_page_state(page, item);
673         local_irq_restore(flags);
674 }
675 EXPORT_SYMBOL(dec_node_page_state);
676 #endif
677
678 /*
679  * Fold a differential into the global counters.
680  * Returns the number of counters updated.
681  */
682 #ifdef CONFIG_NUMA
683 static int fold_diff(int *zone_diff, int *numa_diff, int *node_diff)
684 {
685         int i;
686         int changes = 0;
687
688         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
689                 if (zone_diff[i]) {
690                         atomic_long_add(zone_diff[i], &vm_zone_stat[i]);
691                         changes++;
692         }
693
694         for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
695                 if (numa_diff[i]) {
696                         atomic_long_add(numa_diff[i], &vm_numa_stat[i]);
697                         changes++;
698         }
699
700         for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
701                 if (node_diff[i]) {
702                         atomic_long_add(node_diff[i], &vm_node_stat[i]);
703                         changes++;
704         }
705         return changes;
706 }
707 #else
708 static int fold_diff(int *zone_diff, int *node_diff)
709 {
710         int i;
711         int changes = 0;
712
713         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
714                 if (zone_diff[i]) {
715                         atomic_long_add(zone_diff[i], &vm_zone_stat[i]);
716                         changes++;
717         }
718
719         for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
720                 if (node_diff[i]) {
721                         atomic_long_add(node_diff[i], &vm_node_stat[i]);
722                         changes++;
723         }
724         return changes;
725 }
726 #endif /* CONFIG_NUMA */
727
728 /*
729  * Update the zone counters for the current cpu.
730  *
731  * Note that refresh_cpu_vm_stats strives to only access
732  * node local memory. The per cpu pagesets on remote zones are placed
733  * in the memory local to the processor using that pageset. So the
734  * loop over all zones will access a series of cachelines local to
735  * the processor.
736  *
737  * The call to zone_page_state_add updates the cachelines with the
738  * statistics in the remote zone struct as well as the global cachelines
739  * with the global counters. These could cause remote node cache line
740  * bouncing and will have to be only done when necessary.
741  *
742  * The function returns the number of global counters updated.
743  */
744 static int refresh_cpu_vm_stats(bool do_pagesets)
745 {
746         struct pglist_data *pgdat;
747         struct zone *zone;
748         int i;
749         int global_zone_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
750 #ifdef CONFIG_NUMA
751         int global_numa_diff[NR_VM_NUMA_STAT_ITEMS] = { 0, };
752 #endif
753         int global_node_diff[NR_VM_NODE_STAT_ITEMS] = { 0, };
754         int changes = 0;
755
756         for_each_populated_zone(zone) {
757                 struct per_cpu_pageset __percpu *p = zone->pageset;
758
759                 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
760                         int v;
761
762                         v = this_cpu_xchg(p->vm_stat_diff[i], 0);
763                         if (v) {
764
765                                 atomic_long_add(v, &zone->vm_stat[i]);
766                                 global_zone_diff[i] += v;
767 #ifdef CONFIG_NUMA
768                                 /* 3 seconds idle till flush */
769                                 __this_cpu_write(p->expire, 3);
770 #endif
771                         }
772                 }
773 #ifdef CONFIG_NUMA
774                 for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++) {
775                         int v;
776
777                         v = this_cpu_xchg(p->vm_numa_stat_diff[i], 0);
778                         if (v) {
779
780                                 atomic_long_add(v, &zone->vm_numa_stat[i]);
781                                 global_numa_diff[i] += v;
782                                 __this_cpu_write(p->expire, 3);
783                         }
784                 }
785
786                 if (do_pagesets) {
787                         cond_resched();
788                         /*
789                          * Deal with draining the remote pageset of this
790                          * processor
791                          *
792                          * Check if there are pages remaining in this pageset
793                          * if not then there is nothing to expire.
794                          */
795                         if (!__this_cpu_read(p->expire) ||
796                                !__this_cpu_read(p->pcp.count))
797                                 continue;
798
799                         /*
800                          * We never drain zones local to this processor.
801                          */
802                         if (zone_to_nid(zone) == numa_node_id()) {
803                                 __this_cpu_write(p->expire, 0);
804                                 continue;
805                         }
806
807                         if (__this_cpu_dec_return(p->expire))
808                                 continue;
809
810                         if (__this_cpu_read(p->pcp.count)) {
811                                 drain_zone_pages(zone, this_cpu_ptr(&p->pcp));
812                                 changes++;
813                         }
814                 }
815 #endif
816         }
817
818         for_each_online_pgdat(pgdat) {
819                 struct per_cpu_nodestat __percpu *p = pgdat->per_cpu_nodestats;
820
821                 for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
822                         int v;
823
824                         v = this_cpu_xchg(p->vm_node_stat_diff[i], 0);
825                         if (v) {
826                                 atomic_long_add(v, &pgdat->vm_stat[i]);
827                                 global_node_diff[i] += v;
828                         }
829                 }
830         }
831
832 #ifdef CONFIG_NUMA
833         changes += fold_diff(global_zone_diff, global_numa_diff,
834                              global_node_diff);
835 #else
836         changes += fold_diff(global_zone_diff, global_node_diff);
837 #endif
838         return changes;
839 }
840
841 /*
842  * Fold the data for an offline cpu into the global array.
843  * There cannot be any access by the offline cpu and therefore
844  * synchronization is simplified.
845  */
846 void cpu_vm_stats_fold(int cpu)
847 {
848         struct pglist_data *pgdat;
849         struct zone *zone;
850         int i;
851         int global_zone_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
852 #ifdef CONFIG_NUMA
853         int global_numa_diff[NR_VM_NUMA_STAT_ITEMS] = { 0, };
854 #endif
855         int global_node_diff[NR_VM_NODE_STAT_ITEMS] = { 0, };
856
857         for_each_populated_zone(zone) {
858                 struct per_cpu_pageset *p;
859
860                 p = per_cpu_ptr(zone->pageset, cpu);
861
862                 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
863                         if (p->vm_stat_diff[i]) {
864                                 int v;
865
866                                 v = p->vm_stat_diff[i];
867                                 p->vm_stat_diff[i] = 0;
868                                 atomic_long_add(v, &zone->vm_stat[i]);
869                                 global_zone_diff[i] += v;
870                         }
871
872 #ifdef CONFIG_NUMA
873                 for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
874                         if (p->vm_numa_stat_diff[i]) {
875                                 int v;
876
877                                 v = p->vm_numa_stat_diff[i];
878                                 p->vm_numa_stat_diff[i] = 0;
879                                 atomic_long_add(v, &zone->vm_numa_stat[i]);
880                                 global_numa_diff[i] += v;
881                         }
882 #endif
883         }
884
885         for_each_online_pgdat(pgdat) {
886                 struct per_cpu_nodestat *p;
887
888                 p = per_cpu_ptr(pgdat->per_cpu_nodestats, cpu);
889
890                 for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
891                         if (p->vm_node_stat_diff[i]) {
892                                 int v;
893
894                                 v = p->vm_node_stat_diff[i];
895                                 p->vm_node_stat_diff[i] = 0;
896                                 atomic_long_add(v, &pgdat->vm_stat[i]);
897                                 global_node_diff[i] += v;
898                         }
899         }
900
901 #ifdef CONFIG_NUMA
902         fold_diff(global_zone_diff, global_numa_diff, global_node_diff);
903 #else
904         fold_diff(global_zone_diff, global_node_diff);
905 #endif
906 }
907
908 /*
909  * this is only called if !populated_zone(zone), which implies no other users of
910  * pset->vm_stat_diff[] exsist.
911  */
912 void drain_zonestat(struct zone *zone, struct per_cpu_pageset *pset)
913 {
914         int i;
915
916         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
917                 if (pset->vm_stat_diff[i]) {
918                         int v = pset->vm_stat_diff[i];
919                         pset->vm_stat_diff[i] = 0;
920                         atomic_long_add(v, &zone->vm_stat[i]);
921                         atomic_long_add(v, &vm_zone_stat[i]);
922                 }
923
924 #ifdef CONFIG_NUMA
925         for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
926                 if (pset->vm_numa_stat_diff[i]) {
927                         int v = pset->vm_numa_stat_diff[i];
928
929                         pset->vm_numa_stat_diff[i] = 0;
930                         atomic_long_add(v, &zone->vm_numa_stat[i]);
931                         atomic_long_add(v, &vm_numa_stat[i]);
932                 }
933 #endif
934 }
935 #endif
936
937 #ifdef CONFIG_NUMA
938 void __inc_numa_state(struct zone *zone,
939                                  enum numa_stat_item item)
940 {
941         struct per_cpu_pageset __percpu *pcp = zone->pageset;
942         u16 __percpu *p = pcp->vm_numa_stat_diff + item;
943         u16 v;
944
945         v = __this_cpu_inc_return(*p);
946
947         if (unlikely(v > NUMA_STATS_THRESHOLD)) {
948                 zone_numa_state_add(v, zone, item);
949                 __this_cpu_write(*p, 0);
950         }
951 }
952
953 /*
954  * Determine the per node value of a stat item. This function
955  * is called frequently in a NUMA machine, so try to be as
956  * frugal as possible.
957  */
958 unsigned long sum_zone_node_page_state(int node,
959                                  enum zone_stat_item item)
960 {
961         struct zone *zones = NODE_DATA(node)->node_zones;
962         int i;
963         unsigned long count = 0;
964
965         for (i = 0; i < MAX_NR_ZONES; i++)
966                 count += zone_page_state(zones + i, item);
967
968         return count;
969 }
970
971 /*
972  * Determine the per node value of a numa stat item. To avoid deviation,
973  * the per cpu stat number in vm_numa_stat_diff[] is also included.
974  */
975 unsigned long sum_zone_numa_state(int node,
976                                  enum numa_stat_item item)
977 {
978         struct zone *zones = NODE_DATA(node)->node_zones;
979         int i;
980         unsigned long count = 0;
981
982         for (i = 0; i < MAX_NR_ZONES; i++)
983                 count += zone_numa_state_snapshot(zones + i, item);
984
985         return count;
986 }
987
988 /*
989  * Determine the per node value of a stat item.
990  */
991 unsigned long node_page_state(struct pglist_data *pgdat,
992                                 enum node_stat_item item)
993 {
994         long x = atomic_long_read(&pgdat->vm_stat[item]);
995 #ifdef CONFIG_SMP
996         if (x < 0)
997                 x = 0;
998 #endif
999         return x;
1000 }
1001 #endif
1002
1003 #ifdef CONFIG_COMPACTION
1004
1005 struct contig_page_info {
1006         unsigned long free_pages;
1007         unsigned long free_blocks_total;
1008         unsigned long free_blocks_suitable;
1009 };
1010
1011 /*
1012  * Calculate the number of free pages in a zone, how many contiguous
1013  * pages are free and how many are large enough to satisfy an allocation of
1014  * the target size. Note that this function makes no attempt to estimate
1015  * how many suitable free blocks there *might* be if MOVABLE pages were
1016  * migrated. Calculating that is possible, but expensive and can be
1017  * figured out from userspace
1018  */
1019 static void fill_contig_page_info(struct zone *zone,
1020                                 unsigned int suitable_order,
1021                                 struct contig_page_info *info)
1022 {
1023         unsigned int order;
1024
1025         info->free_pages = 0;
1026         info->free_blocks_total = 0;
1027         info->free_blocks_suitable = 0;
1028
1029         for (order = 0; order < MAX_ORDER; order++) {
1030                 unsigned long blocks;
1031
1032                 /* Count number of free blocks */
1033                 blocks = zone->free_area[order].nr_free;
1034                 info->free_blocks_total += blocks;
1035
1036                 /* Count free base pages */
1037                 info->free_pages += blocks << order;
1038
1039                 /* Count the suitable free blocks */
1040                 if (order >= suitable_order)
1041                         info->free_blocks_suitable += blocks <<
1042                                                 (order - suitable_order);
1043         }
1044 }
1045
1046 /*
1047  * A fragmentation index only makes sense if an allocation of a requested
1048  * size would fail. If that is true, the fragmentation index indicates
1049  * whether external fragmentation or a lack of memory was the problem.
1050  * The value can be used to determine if page reclaim or compaction
1051  * should be used
1052  */
1053 static int __fragmentation_index(unsigned int order, struct contig_page_info *info)
1054 {
1055         unsigned long requested = 1UL << order;
1056
1057         if (WARN_ON_ONCE(order >= MAX_ORDER))
1058                 return 0;
1059
1060         if (!info->free_blocks_total)
1061                 return 0;
1062
1063         /* Fragmentation index only makes sense when a request would fail */
1064         if (info->free_blocks_suitable)
1065                 return -1000;
1066
1067         /*
1068          * Index is between 0 and 1 so return within 3 decimal places
1069          *
1070          * 0 => allocation would fail due to lack of memory
1071          * 1 => allocation would fail due to fragmentation
1072          */
1073         return 1000 - div_u64( (1000+(div_u64(info->free_pages * 1000ULL, requested))), info->free_blocks_total);
1074 }
1075
1076 /* Same as __fragmentation index but allocs contig_page_info on stack */
1077 int fragmentation_index(struct zone *zone, unsigned int order)
1078 {
1079         struct contig_page_info info;
1080
1081         fill_contig_page_info(zone, order, &info);
1082         return __fragmentation_index(order, &info);
1083 }
1084 #endif
1085
1086 #if defined(CONFIG_PROC_FS) || defined(CONFIG_SYSFS) || defined(CONFIG_NUMA)
1087 #ifdef CONFIG_ZONE_DMA
1088 #define TEXT_FOR_DMA(xx) xx "_dma",
1089 #else
1090 #define TEXT_FOR_DMA(xx)
1091 #endif
1092
1093 #ifdef CONFIG_ZONE_DMA32
1094 #define TEXT_FOR_DMA32(xx) xx "_dma32",
1095 #else
1096 #define TEXT_FOR_DMA32(xx)
1097 #endif
1098
1099 #ifdef CONFIG_HIGHMEM
1100 #define TEXT_FOR_HIGHMEM(xx) xx "_high",
1101 #else
1102 #define TEXT_FOR_HIGHMEM(xx)
1103 #endif
1104
1105 #define TEXTS_FOR_ZONES(xx) TEXT_FOR_DMA(xx) TEXT_FOR_DMA32(xx) xx "_normal", \
1106                                         TEXT_FOR_HIGHMEM(xx) xx "_movable",
1107
1108 const char * const vmstat_text[] = {
1109         /* enum zone_stat_item countes */
1110         "nr_free_pages",
1111         "nr_zone_inactive_anon",
1112         "nr_zone_active_anon",
1113         "nr_zone_inactive_file",
1114         "nr_zone_active_file",
1115         "nr_zone_unevictable",
1116         "nr_zone_write_pending",
1117         "nr_mlock",
1118         "nr_page_table_pages",
1119         "nr_kernel_stack",
1120         "nr_bounce",
1121 #if IS_ENABLED(CONFIG_ZSMALLOC)
1122         "nr_zspages",
1123 #endif
1124         "nr_free_cma",
1125
1126         /* enum numa_stat_item counters */
1127 #ifdef CONFIG_NUMA
1128         "numa_hit",
1129         "numa_miss",
1130         "numa_foreign",
1131         "numa_interleave",
1132         "numa_local",
1133         "numa_other",
1134 #endif
1135
1136         /* Node-based counters */
1137         "nr_inactive_anon",
1138         "nr_active_anon",
1139         "nr_inactive_file",
1140         "nr_active_file",
1141         "nr_unevictable",
1142         "nr_slab_reclaimable",
1143         "nr_slab_unreclaimable",
1144         "nr_isolated_anon",
1145         "nr_isolated_file",
1146         "workingset_refault",
1147         "workingset_activate",
1148         "workingset_restore",
1149         "workingset_nodereclaim",
1150         "nr_anon_pages",
1151         "nr_mapped",
1152         "nr_file_pages",
1153         "nr_dirty",
1154         "nr_writeback",
1155         "nr_writeback_temp",
1156         "nr_shmem",
1157         "nr_shmem_hugepages",
1158         "nr_shmem_pmdmapped",
1159         "nr_anon_transparent_hugepages",
1160         "nr_unstable",
1161         "nr_vmscan_write",
1162         "nr_vmscan_immediate_reclaim",
1163         "nr_dirtied",
1164         "nr_written",
1165         "nr_kernel_misc_reclaimable",
1166
1167         /* enum writeback_stat_item counters */
1168         "nr_dirty_threshold",
1169         "nr_dirty_background_threshold",
1170
1171 #ifdef CONFIG_VM_EVENT_COUNTERS
1172         /* enum vm_event_item counters */
1173         "pgpgin",
1174         "pgpgout",
1175         "pswpin",
1176         "pswpout",
1177
1178         TEXTS_FOR_ZONES("pgalloc")
1179         TEXTS_FOR_ZONES("allocstall")
1180         TEXTS_FOR_ZONES("pgskip")
1181
1182         "pgfree",
1183         "pgactivate",
1184         "pgdeactivate",
1185         "pglazyfree",
1186
1187         "pgfault",
1188         "pgmajfault",
1189         "pglazyfreed",
1190
1191         "pgrefill",
1192         "pgsteal_kswapd",
1193         "pgsteal_direct",
1194         "pgscan_kswapd",
1195         "pgscan_direct",
1196         "pgscan_direct_throttle",
1197
1198 #ifdef CONFIG_NUMA
1199         "zone_reclaim_failed",
1200 #endif
1201         "pginodesteal",
1202         "slabs_scanned",
1203         "kswapd_inodesteal",
1204         "kswapd_low_wmark_hit_quickly",
1205         "kswapd_high_wmark_hit_quickly",
1206         "pageoutrun",
1207
1208         "pgrotated",
1209
1210         "drop_pagecache",
1211         "drop_slab",
1212         "oom_kill",
1213
1214 #ifdef CONFIG_NUMA_BALANCING
1215         "numa_pte_updates",
1216         "numa_huge_pte_updates",
1217         "numa_hint_faults",
1218         "numa_hint_faults_local",
1219         "numa_pages_migrated",
1220 #endif
1221 #ifdef CONFIG_MIGRATION
1222         "pgmigrate_success",
1223         "pgmigrate_fail",
1224 #endif
1225 #ifdef CONFIG_COMPACTION
1226         "compact_migrate_scanned",
1227         "compact_free_scanned",
1228         "compact_isolated",
1229         "compact_stall",
1230         "compact_fail",
1231         "compact_success",
1232         "compact_daemon_wake",
1233         "compact_daemon_migrate_scanned",
1234         "compact_daemon_free_scanned",
1235 #endif
1236
1237 #ifdef CONFIG_HUGETLB_PAGE
1238         "htlb_buddy_alloc_success",
1239         "htlb_buddy_alloc_fail",
1240 #endif
1241         "unevictable_pgs_culled",
1242         "unevictable_pgs_scanned",
1243         "unevictable_pgs_rescued",
1244         "unevictable_pgs_mlocked",
1245         "unevictable_pgs_munlocked",
1246         "unevictable_pgs_cleared",
1247         "unevictable_pgs_stranded",
1248
1249 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1250         "thp_fault_alloc",
1251         "thp_fault_fallback",
1252         "thp_collapse_alloc",
1253         "thp_collapse_alloc_failed",
1254         "thp_file_alloc",
1255         "thp_file_mapped",
1256         "thp_split_page",
1257         "thp_split_page_failed",
1258         "thp_deferred_split_page",
1259         "thp_split_pmd",
1260 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
1261         "thp_split_pud",
1262 #endif
1263         "thp_zero_page_alloc",
1264         "thp_zero_page_alloc_failed",
1265         "thp_swpout",
1266         "thp_swpout_fallback",
1267 #endif
1268 #ifdef CONFIG_MEMORY_BALLOON
1269         "balloon_inflate",
1270         "balloon_deflate",
1271 #ifdef CONFIG_BALLOON_COMPACTION
1272         "balloon_migrate",
1273 #endif
1274 #endif /* CONFIG_MEMORY_BALLOON */
1275 #ifdef CONFIG_DEBUG_TLBFLUSH
1276 #ifdef CONFIG_SMP
1277         "nr_tlb_remote_flush",
1278         "nr_tlb_remote_flush_received",
1279 #else
1280         "", /* nr_tlb_remote_flush */
1281         "", /* nr_tlb_remote_flush_received */
1282 #endif /* CONFIG_SMP */
1283         "nr_tlb_local_flush_all",
1284         "nr_tlb_local_flush_one",
1285 #endif /* CONFIG_DEBUG_TLBFLUSH */
1286
1287 #ifdef CONFIG_DEBUG_VM_VMACACHE
1288         "vmacache_find_calls",
1289         "vmacache_find_hits",
1290 #endif
1291 #ifdef CONFIG_SWAP
1292         "swap_ra",
1293         "swap_ra_hit",
1294 #endif
1295 #endif /* CONFIG_VM_EVENTS_COUNTERS */
1296 };
1297 #endif /* CONFIG_PROC_FS || CONFIG_SYSFS || CONFIG_NUMA */
1298
1299 #if (defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)) || \
1300      defined(CONFIG_PROC_FS)
1301 static void *frag_start(struct seq_file *m, loff_t *pos)
1302 {
1303         pg_data_t *pgdat;
1304         loff_t node = *pos;
1305
1306         for (pgdat = first_online_pgdat();
1307              pgdat && node;
1308              pgdat = next_online_pgdat(pgdat))
1309                 --node;
1310
1311         return pgdat;
1312 }
1313
1314 static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
1315 {
1316         pg_data_t *pgdat = (pg_data_t *)arg;
1317
1318         (*pos)++;
1319         return next_online_pgdat(pgdat);
1320 }
1321
1322 static void frag_stop(struct seq_file *m, void *arg)
1323 {
1324 }
1325
1326 /*
1327  * Walk zones in a node and print using a callback.
1328  * If @assert_populated is true, only use callback for zones that are populated.
1329  */
1330 static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat,
1331                 bool assert_populated, bool nolock,
1332                 void (*print)(struct seq_file *m, pg_data_t *, struct zone *))
1333 {
1334         struct zone *zone;
1335         struct zone *node_zones = pgdat->node_zones;
1336         unsigned long flags;
1337
1338         for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
1339                 if (assert_populated && !populated_zone(zone))
1340                         continue;
1341
1342                 if (!nolock)
1343                         spin_lock_irqsave(&zone->lock, flags);
1344                 print(m, pgdat, zone);
1345                 if (!nolock)
1346                         spin_unlock_irqrestore(&zone->lock, flags);
1347         }
1348 }
1349 #endif
1350
1351 #ifdef CONFIG_PROC_FS
1352 static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,
1353                                                 struct zone *zone)
1354 {
1355         int order;
1356
1357         seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
1358         for (order = 0; order < MAX_ORDER; ++order)
1359                 seq_printf(m, "%6lu ", zone->free_area[order].nr_free);
1360         seq_putc(m, '\n');
1361 }
1362
1363 /*
1364  * This walks the free areas for each zone.
1365  */
1366 static int frag_show(struct seq_file *m, void *arg)
1367 {
1368         pg_data_t *pgdat = (pg_data_t *)arg;
1369         walk_zones_in_node(m, pgdat, true, false, frag_show_print);
1370         return 0;
1371 }
1372
1373 static void pagetypeinfo_showfree_print(struct seq_file *m,
1374                                         pg_data_t *pgdat, struct zone *zone)
1375 {
1376         int order, mtype;
1377
1378         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++) {
1379                 seq_printf(m, "Node %4d, zone %8s, type %12s ",
1380                                         pgdat->node_id,
1381                                         zone->name,
1382                                         migratetype_names[mtype]);
1383                 for (order = 0; order < MAX_ORDER; ++order) {
1384                         unsigned long freecount = 0;
1385                         struct free_area *area;
1386                         struct list_head *curr;
1387
1388                         area = &(zone->free_area[order]);
1389
1390                         list_for_each(curr, &area->free_list[mtype])
1391                                 freecount++;
1392                         seq_printf(m, "%6lu ", freecount);
1393                 }
1394                 seq_putc(m, '\n');
1395         }
1396 }
1397
1398 /* Print out the free pages at each order for each migatetype */
1399 static int pagetypeinfo_showfree(struct seq_file *m, void *arg)
1400 {
1401         int order;
1402         pg_data_t *pgdat = (pg_data_t *)arg;
1403
1404         /* Print header */
1405         seq_printf(m, "%-43s ", "Free pages count per migrate type at order");
1406         for (order = 0; order < MAX_ORDER; ++order)
1407                 seq_printf(m, "%6d ", order);
1408         seq_putc(m, '\n');
1409
1410         walk_zones_in_node(m, pgdat, true, false, pagetypeinfo_showfree_print);
1411
1412         return 0;
1413 }
1414
1415 static void pagetypeinfo_showblockcount_print(struct seq_file *m,
1416                                         pg_data_t *pgdat, struct zone *zone)
1417 {
1418         int mtype;
1419         unsigned long pfn;
1420         unsigned long start_pfn = zone->zone_start_pfn;
1421         unsigned long end_pfn = zone_end_pfn(zone);
1422         unsigned long count[MIGRATE_TYPES] = { 0, };
1423
1424         for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
1425                 struct page *page;
1426
1427                 page = pfn_to_online_page(pfn);
1428                 if (!page)
1429                         continue;
1430
1431                 /* Watch for unexpected holes punched in the memmap */
1432                 if (!memmap_valid_within(pfn, page, zone))
1433                         continue;
1434
1435                 if (page_zone(page) != zone)
1436                         continue;
1437
1438                 mtype = get_pageblock_migratetype(page);
1439
1440                 if (mtype < MIGRATE_TYPES)
1441                         count[mtype]++;
1442         }
1443
1444         /* Print counts */
1445         seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
1446         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
1447                 seq_printf(m, "%12lu ", count[mtype]);
1448         seq_putc(m, '\n');
1449 }
1450
1451 /* Print out the number of pageblocks for each migratetype */
1452 static int pagetypeinfo_showblockcount(struct seq_file *m, void *arg)
1453 {
1454         int mtype;
1455         pg_data_t *pgdat = (pg_data_t *)arg;
1456
1457         seq_printf(m, "\n%-23s", "Number of blocks type ");
1458         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
1459                 seq_printf(m, "%12s ", migratetype_names[mtype]);
1460         seq_putc(m, '\n');
1461         walk_zones_in_node(m, pgdat, true, false,
1462                 pagetypeinfo_showblockcount_print);
1463
1464         return 0;
1465 }
1466
1467 /*
1468  * Print out the number of pageblocks for each migratetype that contain pages
1469  * of other types. This gives an indication of how well fallbacks are being
1470  * contained by rmqueue_fallback(). It requires information from PAGE_OWNER
1471  * to determine what is going on
1472  */
1473 static void pagetypeinfo_showmixedcount(struct seq_file *m, pg_data_t *pgdat)
1474 {
1475 #ifdef CONFIG_PAGE_OWNER
1476         int mtype;
1477
1478         if (!static_branch_unlikely(&page_owner_inited))
1479                 return;
1480
1481         drain_all_pages(NULL);
1482
1483         seq_printf(m, "\n%-23s", "Number of mixed blocks ");
1484         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
1485                 seq_printf(m, "%12s ", migratetype_names[mtype]);
1486         seq_putc(m, '\n');
1487
1488         walk_zones_in_node(m, pgdat, true, true,
1489                 pagetypeinfo_showmixedcount_print);
1490 #endif /* CONFIG_PAGE_OWNER */
1491 }
1492
1493 /*
1494  * This prints out statistics in relation to grouping pages by mobility.
1495  * It is expensive to collect so do not constantly read the file.
1496  */
1497 static int pagetypeinfo_show(struct seq_file *m, void *arg)
1498 {
1499         pg_data_t *pgdat = (pg_data_t *)arg;
1500
1501         /* check memoryless node */
1502         if (!node_state(pgdat->node_id, N_MEMORY))
1503                 return 0;
1504
1505         seq_printf(m, "Page block order: %d\n", pageblock_order);
1506         seq_printf(m, "Pages per block:  %lu\n", pageblock_nr_pages);
1507         seq_putc(m, '\n');
1508         pagetypeinfo_showfree(m, pgdat);
1509         pagetypeinfo_showblockcount(m, pgdat);
1510         pagetypeinfo_showmixedcount(m, pgdat);
1511
1512         return 0;
1513 }
1514
1515 static const struct seq_operations fragmentation_op = {
1516         .start  = frag_start,
1517         .next   = frag_next,
1518         .stop   = frag_stop,
1519         .show   = frag_show,
1520 };
1521
1522 static const struct seq_operations pagetypeinfo_op = {
1523         .start  = frag_start,
1524         .next   = frag_next,
1525         .stop   = frag_stop,
1526         .show   = pagetypeinfo_show,
1527 };
1528
1529 static bool is_zone_first_populated(pg_data_t *pgdat, struct zone *zone)
1530 {
1531         int zid;
1532
1533         for (zid = 0; zid < MAX_NR_ZONES; zid++) {
1534                 struct zone *compare = &pgdat->node_zones[zid];
1535
1536                 if (populated_zone(compare))
1537                         return zone == compare;
1538         }
1539
1540         return false;
1541 }
1542
1543 static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
1544                                                         struct zone *zone)
1545 {
1546         int i;
1547         seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name);
1548         if (is_zone_first_populated(pgdat, zone)) {
1549                 seq_printf(m, "\n  per-node stats");
1550                 for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
1551                         seq_printf(m, "\n      %-12s %lu",
1552                                 vmstat_text[i + NR_VM_ZONE_STAT_ITEMS +
1553                                 NR_VM_NUMA_STAT_ITEMS],
1554                                 node_page_state(pgdat, i));
1555                 }
1556         }
1557         seq_printf(m,
1558                    "\n  pages free     %lu"
1559                    "\n        min      %lu"
1560                    "\n        low      %lu"
1561                    "\n        high     %lu"
1562                    "\n        spanned  %lu"
1563                    "\n        present  %lu"
1564                    "\n        managed  %lu",
1565                    zone_page_state(zone, NR_FREE_PAGES),
1566                    min_wmark_pages(zone),
1567                    low_wmark_pages(zone),
1568                    high_wmark_pages(zone),
1569                    zone->spanned_pages,
1570                    zone->present_pages,
1571                    zone->managed_pages);
1572
1573         seq_printf(m,
1574                    "\n        protection: (%ld",
1575                    zone->lowmem_reserve[0]);
1576         for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++)
1577                 seq_printf(m, ", %ld", zone->lowmem_reserve[i]);
1578         seq_putc(m, ')');
1579
1580         /* If unpopulated, no other information is useful */
1581         if (!populated_zone(zone)) {
1582                 seq_putc(m, '\n');
1583                 return;
1584         }
1585
1586         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
1587                 seq_printf(m, "\n      %-12s %lu", vmstat_text[i],
1588                                 zone_page_state(zone, i));
1589
1590 #ifdef CONFIG_NUMA
1591         for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
1592                 seq_printf(m, "\n      %-12s %lu",
1593                                 vmstat_text[i + NR_VM_ZONE_STAT_ITEMS],
1594                                 zone_numa_state_snapshot(zone, i));
1595 #endif
1596
1597         seq_printf(m, "\n  pagesets");
1598         for_each_online_cpu(i) {
1599                 struct per_cpu_pageset *pageset;
1600
1601                 pageset = per_cpu_ptr(zone->pageset, i);
1602                 seq_printf(m,
1603                            "\n    cpu: %i"
1604                            "\n              count: %i"
1605                            "\n              high:  %i"
1606                            "\n              batch: %i",
1607                            i,
1608                            pageset->pcp.count,
1609                            pageset->pcp.high,
1610                            pageset->pcp.batch);
1611 #ifdef CONFIG_SMP
1612                 seq_printf(m, "\n  vm stats threshold: %d",
1613                                 pageset->stat_threshold);
1614 #endif
1615         }
1616         seq_printf(m,
1617                    "\n  node_unreclaimable:  %u"
1618                    "\n  start_pfn:           %lu",
1619                    pgdat->kswapd_failures >= MAX_RECLAIM_RETRIES,
1620                    zone->zone_start_pfn);
1621         seq_putc(m, '\n');
1622 }
1623
1624 /*
1625  * Output information about zones in @pgdat.  All zones are printed regardless
1626  * of whether they are populated or not: lowmem_reserve_ratio operates on the
1627  * set of all zones and userspace would not be aware of such zones if they are
1628  * suppressed here (zoneinfo displays the effect of lowmem_reserve_ratio).
1629  */
1630 static int zoneinfo_show(struct seq_file *m, void *arg)
1631 {
1632         pg_data_t *pgdat = (pg_data_t *)arg;
1633         walk_zones_in_node(m, pgdat, false, false, zoneinfo_show_print);
1634         return 0;
1635 }
1636
1637 static const struct seq_operations zoneinfo_op = {
1638         .start  = frag_start, /* iterate over all zones. The same as in
1639                                * fragmentation. */
1640         .next   = frag_next,
1641         .stop   = frag_stop,
1642         .show   = zoneinfo_show,
1643 };
1644
1645 enum writeback_stat_item {
1646         NR_DIRTY_THRESHOLD,
1647         NR_DIRTY_BG_THRESHOLD,
1648         NR_VM_WRITEBACK_STAT_ITEMS,
1649 };
1650
1651 static void *vmstat_start(struct seq_file *m, loff_t *pos)
1652 {
1653         unsigned long *v;
1654         int i, stat_items_size;
1655
1656         if (*pos >= ARRAY_SIZE(vmstat_text))
1657                 return NULL;
1658         stat_items_size = NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long) +
1659                           NR_VM_NUMA_STAT_ITEMS * sizeof(unsigned long) +
1660                           NR_VM_NODE_STAT_ITEMS * sizeof(unsigned long) +
1661                           NR_VM_WRITEBACK_STAT_ITEMS * sizeof(unsigned long);
1662
1663 #ifdef CONFIG_VM_EVENT_COUNTERS
1664         stat_items_size += sizeof(struct vm_event_state);
1665 #endif
1666
1667         v = kmalloc(stat_items_size, GFP_KERNEL);
1668         m->private = v;
1669         if (!v)
1670                 return ERR_PTR(-ENOMEM);
1671         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
1672                 v[i] = global_zone_page_state(i);
1673         v += NR_VM_ZONE_STAT_ITEMS;
1674
1675 #ifdef CONFIG_NUMA
1676         for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
1677                 v[i] = global_numa_state(i);
1678         v += NR_VM_NUMA_STAT_ITEMS;
1679 #endif
1680
1681         for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
1682                 v[i] = global_node_page_state(i);
1683         v += NR_VM_NODE_STAT_ITEMS;
1684
1685         global_dirty_limits(v + NR_DIRTY_BG_THRESHOLD,
1686                             v + NR_DIRTY_THRESHOLD);
1687         v += NR_VM_WRITEBACK_STAT_ITEMS;
1688
1689 #ifdef CONFIG_VM_EVENT_COUNTERS
1690         all_vm_events(v);
1691         v[PGPGIN] /= 2;         /* sectors -> kbytes */
1692         v[PGPGOUT] /= 2;
1693 #endif
1694         return (unsigned long *)m->private + *pos;
1695 }
1696
1697 static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)
1698 {
1699         (*pos)++;
1700         if (*pos >= ARRAY_SIZE(vmstat_text))
1701                 return NULL;
1702         return (unsigned long *)m->private + *pos;
1703 }
1704
1705 static int vmstat_show(struct seq_file *m, void *arg)
1706 {
1707         unsigned long *l = arg;
1708         unsigned long off = l - (unsigned long *)m->private;
1709
1710         seq_puts(m, vmstat_text[off]);
1711         seq_put_decimal_ull(m, " ", *l);
1712         seq_putc(m, '\n');
1713         return 0;
1714 }
1715
1716 static void vmstat_stop(struct seq_file *m, void *arg)
1717 {
1718         kfree(m->private);
1719         m->private = NULL;
1720 }
1721
1722 static const struct seq_operations vmstat_op = {
1723         .start  = vmstat_start,
1724         .next   = vmstat_next,
1725         .stop   = vmstat_stop,
1726         .show   = vmstat_show,
1727 };
1728 #endif /* CONFIG_PROC_FS */
1729
1730 #ifdef CONFIG_SMP
1731 static DEFINE_PER_CPU(struct delayed_work, vmstat_work);
1732 int sysctl_stat_interval __read_mostly = HZ;
1733
1734 #ifdef CONFIG_PROC_FS
1735 static void refresh_vm_stats(struct work_struct *work)
1736 {
1737         refresh_cpu_vm_stats(true);
1738 }
1739
1740 int vmstat_refresh(struct ctl_table *table, int write,
1741                    void __user *buffer, size_t *lenp, loff_t *ppos)
1742 {
1743         long val;
1744         int err;
1745         int i;
1746
1747         /*
1748          * The regular update, every sysctl_stat_interval, may come later
1749          * than expected: leaving a significant amount in per_cpu buckets.
1750          * This is particularly misleading when checking a quantity of HUGE
1751          * pages, immediately after running a test.  /proc/sys/vm/stat_refresh,
1752          * which can equally be echo'ed to or cat'ted from (by root),
1753          * can be used to update the stats just before reading them.
1754          *
1755          * Oh, and since global_zone_page_state() etc. are so careful to hide
1756          * transiently negative values, report an error here if any of
1757          * the stats is negative, so we know to go looking for imbalance.
1758          */
1759         err = schedule_on_each_cpu(refresh_vm_stats);
1760         if (err)
1761                 return err;
1762         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
1763                 val = atomic_long_read(&vm_zone_stat[i]);
1764                 if (val < 0) {
1765                         pr_warn("%s: %s %ld\n",
1766                                 __func__, vmstat_text[i], val);
1767                         err = -EINVAL;
1768                 }
1769         }
1770 #ifdef CONFIG_NUMA
1771         for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++) {
1772                 val = atomic_long_read(&vm_numa_stat[i]);
1773                 if (val < 0) {
1774                         pr_warn("%s: %s %ld\n",
1775                                 __func__, vmstat_text[i + NR_VM_ZONE_STAT_ITEMS], val);
1776                         err = -EINVAL;
1777                 }
1778         }
1779 #endif
1780         if (err)
1781                 return err;
1782         if (write)
1783                 *ppos += *lenp;
1784         else
1785                 *lenp = 0;
1786         return 0;
1787 }
1788 #endif /* CONFIG_PROC_FS */
1789
1790 static void vmstat_update(struct work_struct *w)
1791 {
1792         if (refresh_cpu_vm_stats(true)) {
1793                 /*
1794                  * Counters were updated so we expect more updates
1795                  * to occur in the future. Keep on running the
1796                  * update worker thread.
1797                  */
1798                 queue_delayed_work_on(smp_processor_id(), mm_percpu_wq,
1799                                 this_cpu_ptr(&vmstat_work),
1800                                 round_jiffies_relative(sysctl_stat_interval));
1801         }
1802 }
1803
1804 /*
1805  * Switch off vmstat processing and then fold all the remaining differentials
1806  * until the diffs stay at zero. The function is used by NOHZ and can only be
1807  * invoked when tick processing is not active.
1808  */
1809 /*
1810  * Check if the diffs for a certain cpu indicate that
1811  * an update is needed.
1812  */
1813 static bool need_update(int cpu)
1814 {
1815         struct zone *zone;
1816
1817         for_each_populated_zone(zone) {
1818                 struct per_cpu_pageset *p = per_cpu_ptr(zone->pageset, cpu);
1819
1820                 BUILD_BUG_ON(sizeof(p->vm_stat_diff[0]) != 1);
1821 #ifdef CONFIG_NUMA
1822                 BUILD_BUG_ON(sizeof(p->vm_numa_stat_diff[0]) != 2);
1823 #endif
1824
1825                 /*
1826                  * The fast way of checking if there are any vmstat diffs.
1827                  * This works because the diffs are byte sized items.
1828                  */
1829                 if (memchr_inv(p->vm_stat_diff, 0, NR_VM_ZONE_STAT_ITEMS))
1830                         return true;
1831 #ifdef CONFIG_NUMA
1832                 if (memchr_inv(p->vm_numa_stat_diff, 0, NR_VM_NUMA_STAT_ITEMS))
1833                         return true;
1834 #endif
1835         }
1836         return false;
1837 }
1838
1839 /*
1840  * Switch off vmstat processing and then fold all the remaining differentials
1841  * until the diffs stay at zero. The function is used by NOHZ and can only be
1842  * invoked when tick processing is not active.
1843  */
1844 void quiet_vmstat(void)
1845 {
1846         if (system_state != SYSTEM_RUNNING)
1847                 return;
1848
1849         if (!delayed_work_pending(this_cpu_ptr(&vmstat_work)))
1850                 return;
1851
1852         if (!need_update(smp_processor_id()))
1853                 return;
1854
1855         /*
1856          * Just refresh counters and do not care about the pending delayed
1857          * vmstat_update. It doesn't fire that often to matter and canceling
1858          * it would be too expensive from this path.
1859          * vmstat_shepherd will take care about that for us.
1860          */
1861         refresh_cpu_vm_stats(false);
1862 }
1863
1864 /*
1865  * Shepherd worker thread that checks the
1866  * differentials of processors that have their worker
1867  * threads for vm statistics updates disabled because of
1868  * inactivity.
1869  */
1870 static void vmstat_shepherd(struct work_struct *w);
1871
1872 static DECLARE_DEFERRABLE_WORK(shepherd, vmstat_shepherd);
1873
1874 static void vmstat_shepherd(struct work_struct *w)
1875 {
1876         int cpu;
1877
1878         get_online_cpus();
1879         /* Check processors whose vmstat worker threads have been disabled */
1880         for_each_online_cpu(cpu) {
1881                 struct delayed_work *dw = &per_cpu(vmstat_work, cpu);
1882
1883                 if (!delayed_work_pending(dw) && need_update(cpu))
1884                         queue_delayed_work_on(cpu, mm_percpu_wq, dw, 0);
1885         }
1886         put_online_cpus();
1887
1888         schedule_delayed_work(&shepherd,
1889                 round_jiffies_relative(sysctl_stat_interval));
1890 }
1891
1892 static void __init start_shepherd_timer(void)
1893 {
1894         int cpu;
1895
1896         for_each_possible_cpu(cpu)
1897                 INIT_DEFERRABLE_WORK(per_cpu_ptr(&vmstat_work, cpu),
1898                         vmstat_update);
1899
1900         schedule_delayed_work(&shepherd,
1901                 round_jiffies_relative(sysctl_stat_interval));
1902 }
1903
1904 static void __init init_cpu_node_state(void)
1905 {
1906         int node;
1907
1908         for_each_online_node(node) {
1909                 if (cpumask_weight(cpumask_of_node(node)) > 0)
1910                         node_set_state(node, N_CPU);
1911         }
1912 }
1913
1914 static int vmstat_cpu_online(unsigned int cpu)
1915 {
1916         refresh_zone_stat_thresholds();
1917         node_set_state(cpu_to_node(cpu), N_CPU);
1918         return 0;
1919 }
1920
1921 static int vmstat_cpu_down_prep(unsigned int cpu)
1922 {
1923         cancel_delayed_work_sync(&per_cpu(vmstat_work, cpu));
1924         return 0;
1925 }
1926
1927 static int vmstat_cpu_dead(unsigned int cpu)
1928 {
1929         const struct cpumask *node_cpus;
1930         int node;
1931
1932         node = cpu_to_node(cpu);
1933
1934         refresh_zone_stat_thresholds();
1935         node_cpus = cpumask_of_node(node);
1936         if (cpumask_weight(node_cpus) > 0)
1937                 return 0;
1938
1939         node_clear_state(node, N_CPU);
1940         return 0;
1941 }
1942
1943 #endif
1944
1945 struct workqueue_struct *mm_percpu_wq;
1946
1947 void __init init_mm_internals(void)
1948 {
1949         int ret __maybe_unused;
1950
1951         mm_percpu_wq = alloc_workqueue("mm_percpu_wq", WQ_MEM_RECLAIM, 0);
1952
1953 #ifdef CONFIG_SMP
1954         ret = cpuhp_setup_state_nocalls(CPUHP_MM_VMSTAT_DEAD, "mm/vmstat:dead",
1955                                         NULL, vmstat_cpu_dead);
1956         if (ret < 0)
1957                 pr_err("vmstat: failed to register 'dead' hotplug state\n");
1958
1959         ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "mm/vmstat:online",
1960                                         vmstat_cpu_online,
1961                                         vmstat_cpu_down_prep);
1962         if (ret < 0)
1963                 pr_err("vmstat: failed to register 'online' hotplug state\n");
1964
1965         get_online_cpus();
1966         init_cpu_node_state();
1967         put_online_cpus();
1968
1969         start_shepherd_timer();
1970 #endif
1971 #ifdef CONFIG_PROC_FS
1972         proc_create_seq("buddyinfo", 0444, NULL, &fragmentation_op);
1973         proc_create_seq("pagetypeinfo", 0444, NULL, &pagetypeinfo_op);
1974         proc_create_seq("vmstat", 0444, NULL, &vmstat_op);
1975         proc_create_seq("zoneinfo", 0444, NULL, &zoneinfo_op);
1976 #endif
1977 }
1978
1979 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)
1980
1981 /*
1982  * Return an index indicating how much of the available free memory is
1983  * unusable for an allocation of the requested size.
1984  */
1985 static int unusable_free_index(unsigned int order,
1986                                 struct contig_page_info *info)
1987 {
1988         /* No free memory is interpreted as all free memory is unusable */
1989         if (info->free_pages == 0)
1990                 return 1000;
1991
1992         /*
1993          * Index should be a value between 0 and 1. Return a value to 3
1994          * decimal places.
1995          *
1996          * 0 => no fragmentation
1997          * 1 => high fragmentation
1998          */
1999         return div_u64((info->free_pages - (info->free_blocks_suitable << order)) * 1000ULL, info->free_pages);
2000
2001 }
2002
2003 static void unusable_show_print(struct seq_file *m,
2004                                         pg_data_t *pgdat, struct zone *zone)
2005 {
2006         unsigned int order;
2007         int index;
2008         struct contig_page_info info;
2009
2010         seq_printf(m, "Node %d, zone %8s ",
2011                                 pgdat->node_id,
2012                                 zone->name);
2013         for (order = 0; order < MAX_ORDER; ++order) {
2014                 fill_contig_page_info(zone, order, &info);
2015                 index = unusable_free_index(order, &info);
2016                 seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
2017         }
2018
2019         seq_putc(m, '\n');
2020 }
2021
2022 /*
2023  * Display unusable free space index
2024  *
2025  * The unusable free space index measures how much of the available free
2026  * memory cannot be used to satisfy an allocation of a given size and is a
2027  * value between 0 and 1. The higher the value, the more of free memory is
2028  * unusable and by implication, the worse the external fragmentation is. This
2029  * can be expressed as a percentage by multiplying by 100.
2030  */
2031 static int unusable_show(struct seq_file *m, void *arg)
2032 {
2033         pg_data_t *pgdat = (pg_data_t *)arg;
2034
2035         /* check memoryless node */
2036         if (!node_state(pgdat->node_id, N_MEMORY))
2037                 return 0;
2038
2039         walk_zones_in_node(m, pgdat, true, false, unusable_show_print);
2040
2041         return 0;
2042 }
2043
2044 static const struct seq_operations unusable_op = {
2045         .start  = frag_start,
2046         .next   = frag_next,
2047         .stop   = frag_stop,
2048         .show   = unusable_show,
2049 };
2050
2051 static int unusable_open(struct inode *inode, struct file *file)
2052 {
2053         return seq_open(file, &unusable_op);
2054 }
2055
2056 static const struct file_operations unusable_file_ops = {
2057         .open           = unusable_open,
2058         .read           = seq_read,
2059         .llseek         = seq_lseek,
2060         .release        = seq_release,
2061 };
2062
2063 static void extfrag_show_print(struct seq_file *m,
2064                                         pg_data_t *pgdat, struct zone *zone)
2065 {
2066         unsigned int order;
2067         int index;
2068
2069         /* Alloc on stack as interrupts are disabled for zone walk */
2070         struct contig_page_info info;
2071
2072         seq_printf(m, "Node %d, zone %8s ",
2073                                 pgdat->node_id,
2074                                 zone->name);
2075         for (order = 0; order < MAX_ORDER; ++order) {
2076                 fill_contig_page_info(zone, order, &info);
2077                 index = __fragmentation_index(order, &info);
2078                 seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
2079         }
2080
2081         seq_putc(m, '\n');
2082 }
2083
2084 /*
2085  * Display fragmentation index for orders that allocations would fail for
2086  */
2087 static int extfrag_show(struct seq_file *m, void *arg)
2088 {
2089         pg_data_t *pgdat = (pg_data_t *)arg;
2090
2091         walk_zones_in_node(m, pgdat, true, false, extfrag_show_print);
2092
2093         return 0;
2094 }
2095
2096 static const struct seq_operations extfrag_op = {
2097         .start  = frag_start,
2098         .next   = frag_next,
2099         .stop   = frag_stop,
2100         .show   = extfrag_show,
2101 };
2102
2103 static int extfrag_open(struct inode *inode, struct file *file)
2104 {
2105         return seq_open(file, &extfrag_op);
2106 }
2107
2108 static const struct file_operations extfrag_file_ops = {
2109         .open           = extfrag_open,
2110         .read           = seq_read,
2111         .llseek         = seq_lseek,
2112         .release        = seq_release,
2113 };
2114
2115 static int __init extfrag_debug_init(void)
2116 {
2117         struct dentry *extfrag_debug_root;
2118
2119         extfrag_debug_root = debugfs_create_dir("extfrag", NULL);
2120         if (!extfrag_debug_root)
2121                 return -ENOMEM;
2122
2123         if (!debugfs_create_file("unusable_index", 0444,
2124                         extfrag_debug_root, NULL, &unusable_file_ops))
2125                 goto fail;
2126
2127         if (!debugfs_create_file("extfrag_index", 0444,
2128                         extfrag_debug_root, NULL, &extfrag_file_ops))
2129                 goto fail;
2130
2131         return 0;
2132 fail:
2133         debugfs_remove_recursive(extfrag_debug_root);
2134         return -ENOMEM;
2135 }
2136
2137 module_init(extfrag_debug_init);
2138 #endif