Merge tag 'timers-core-2022-08-01' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux-2.6-microblaze.git] / mm / vmstat.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  linux/mm/vmstat.c
4  *
5  *  Manages VM statistics
6  *  Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
7  *
8  *  zoned VM statistics
9  *  Copyright (C) 2006 Silicon Graphics, Inc.,
10  *              Christoph Lameter <christoph@lameter.com>
11  *  Copyright (C) 2008-2014 Christoph Lameter
12  */
13 #include <linux/fs.h>
14 #include <linux/mm.h>
15 #include <linux/err.h>
16 #include <linux/module.h>
17 #include <linux/slab.h>
18 #include <linux/cpu.h>
19 #include <linux/cpumask.h>
20 #include <linux/vmstat.h>
21 #include <linux/proc_fs.h>
22 #include <linux/seq_file.h>
23 #include <linux/debugfs.h>
24 #include <linux/sched.h>
25 #include <linux/math64.h>
26 #include <linux/writeback.h>
27 #include <linux/compaction.h>
28 #include <linux/mm_inline.h>
29 #include <linux/page_ext.h>
30 #include <linux/page_owner.h>
31 #include <linux/migrate.h>
32
33 #include "internal.h"
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_EVENT_ITEMS; item++) {
44                 atomic_long_set(&zone->vm_numa_event[item], 0);
45                 for_each_online_cpu(cpu) {
46                         per_cpu_ptr(zone->per_cpu_zonestats, cpu)->vm_numa_event[item]
47                                                 = 0;
48                 }
49         }
50 }
51
52 /* zero numa counters of all the populated zones */
53 static void zero_zones_numa_counters(void)
54 {
55         struct zone *zone;
56
57         for_each_populated_zone(zone)
58                 zero_zone_numa_counters(zone);
59 }
60
61 /* zero global numa counters */
62 static void zero_global_numa_counters(void)
63 {
64         int item;
65
66         for (item = 0; item < NR_VM_NUMA_EVENT_ITEMS; item++)
67                 atomic_long_set(&vm_numa_event[item], 0);
68 }
69
70 static void invalid_numa_statistics(void)
71 {
72         zero_zones_numa_counters();
73         zero_global_numa_counters();
74 }
75
76 static DEFINE_MUTEX(vm_numa_stat_lock);
77
78 int sysctl_vm_numa_stat_handler(struct ctl_table *table, int write,
79                 void *buffer, size_t *length, loff_t *ppos)
80 {
81         int ret, oldval;
82
83         mutex_lock(&vm_numa_stat_lock);
84         if (write)
85                 oldval = sysctl_vm_numa_stat;
86         ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
87         if (ret || !write)
88                 goto out;
89
90         if (oldval == sysctl_vm_numa_stat)
91                 goto out;
92         else if (sysctl_vm_numa_stat == ENABLE_NUMA_STAT) {
93                 static_branch_enable(&vm_numa_stat_key);
94                 pr_info("enable numa statistics\n");
95         } else {
96                 static_branch_disable(&vm_numa_stat_key);
97                 invalid_numa_statistics();
98                 pr_info("disable numa statistics, and clear numa counters\n");
99         }
100
101 out:
102         mutex_unlock(&vm_numa_stat_lock);
103         return ret;
104 }
105 #endif
106
107 #ifdef CONFIG_VM_EVENT_COUNTERS
108 DEFINE_PER_CPU(struct vm_event_state, vm_event_states) = {{0}};
109 EXPORT_PER_CPU_SYMBOL(vm_event_states);
110
111 static void sum_vm_events(unsigned long *ret)
112 {
113         int cpu;
114         int i;
115
116         memset(ret, 0, NR_VM_EVENT_ITEMS * sizeof(unsigned long));
117
118         for_each_online_cpu(cpu) {
119                 struct vm_event_state *this = &per_cpu(vm_event_states, cpu);
120
121                 for (i = 0; i < NR_VM_EVENT_ITEMS; i++)
122                         ret[i] += this->event[i];
123         }
124 }
125
126 /*
127  * Accumulate the vm event counters across all CPUs.
128  * The result is unavoidably approximate - it can change
129  * during and after execution of this function.
130 */
131 void all_vm_events(unsigned long *ret)
132 {
133         cpus_read_lock();
134         sum_vm_events(ret);
135         cpus_read_unlock();
136 }
137 EXPORT_SYMBOL_GPL(all_vm_events);
138
139 /*
140  * Fold the foreign cpu events into our own.
141  *
142  * This is adding to the events on one processor
143  * but keeps the global counts constant.
144  */
145 void vm_events_fold_cpu(int cpu)
146 {
147         struct vm_event_state *fold_state = &per_cpu(vm_event_states, cpu);
148         int i;
149
150         for (i = 0; i < NR_VM_EVENT_ITEMS; i++) {
151                 count_vm_events(i, fold_state->event[i]);
152                 fold_state->event[i] = 0;
153         }
154 }
155
156 #endif /* CONFIG_VM_EVENT_COUNTERS */
157
158 /*
159  * Manage combined zone based / global counters
160  *
161  * vm_stat contains the global counters
162  */
163 atomic_long_t vm_zone_stat[NR_VM_ZONE_STAT_ITEMS] __cacheline_aligned_in_smp;
164 atomic_long_t vm_node_stat[NR_VM_NODE_STAT_ITEMS] __cacheline_aligned_in_smp;
165 atomic_long_t vm_numa_event[NR_VM_NUMA_EVENT_ITEMS] __cacheline_aligned_in_smp;
166 EXPORT_SYMBOL(vm_zone_stat);
167 EXPORT_SYMBOL(vm_node_stat);
168
169 #ifdef CONFIG_NUMA
170 static void fold_vm_zone_numa_events(struct zone *zone)
171 {
172         unsigned long zone_numa_events[NR_VM_NUMA_EVENT_ITEMS] = { 0, };
173         int cpu;
174         enum numa_stat_item item;
175
176         for_each_online_cpu(cpu) {
177                 struct per_cpu_zonestat *pzstats;
178
179                 pzstats = per_cpu_ptr(zone->per_cpu_zonestats, cpu);
180                 for (item = 0; item < NR_VM_NUMA_EVENT_ITEMS; item++)
181                         zone_numa_events[item] += xchg(&pzstats->vm_numa_event[item], 0);
182         }
183
184         for (item = 0; item < NR_VM_NUMA_EVENT_ITEMS; item++)
185                 zone_numa_event_add(zone_numa_events[item], zone, item);
186 }
187
188 void fold_vm_numa_events(void)
189 {
190         struct zone *zone;
191
192         for_each_populated_zone(zone)
193                 fold_vm_zone_numa_events(zone);
194 }
195 #endif
196
197 #ifdef CONFIG_SMP
198
199 int calculate_pressure_threshold(struct zone *zone)
200 {
201         int threshold;
202         int watermark_distance;
203
204         /*
205          * As vmstats are not up to date, there is drift between the estimated
206          * and real values. For high thresholds and a high number of CPUs, it
207          * is possible for the min watermark to be breached while the estimated
208          * value looks fine. The pressure threshold is a reduced value such
209          * that even the maximum amount of drift will not accidentally breach
210          * the min watermark
211          */
212         watermark_distance = low_wmark_pages(zone) - min_wmark_pages(zone);
213         threshold = max(1, (int)(watermark_distance / num_online_cpus()));
214
215         /*
216          * Maximum threshold is 125
217          */
218         threshold = min(125, threshold);
219
220         return threshold;
221 }
222
223 int calculate_normal_threshold(struct zone *zone)
224 {
225         int threshold;
226         int mem;        /* memory in 128 MB units */
227
228         /*
229          * The threshold scales with the number of processors and the amount
230          * of memory per zone. More memory means that we can defer updates for
231          * longer, more processors could lead to more contention.
232          * fls() is used to have a cheap way of logarithmic scaling.
233          *
234          * Some sample thresholds:
235          *
236          * Threshold    Processors      (fls)   Zonesize        fls(mem)+1
237          * ------------------------------------------------------------------
238          * 8            1               1       0.9-1 GB        4
239          * 16           2               2       0.9-1 GB        4
240          * 20           2               2       1-2 GB          5
241          * 24           2               2       2-4 GB          6
242          * 28           2               2       4-8 GB          7
243          * 32           2               2       8-16 GB         8
244          * 4            2               2       <128M           1
245          * 30           4               3       2-4 GB          5
246          * 48           4               3       8-16 GB         8
247          * 32           8               4       1-2 GB          4
248          * 32           8               4       0.9-1GB         4
249          * 10           16              5       <128M           1
250          * 40           16              5       900M            4
251          * 70           64              7       2-4 GB          5
252          * 84           64              7       4-8 GB          6
253          * 108          512             9       4-8 GB          6
254          * 125          1024            10      8-16 GB         8
255          * 125          1024            10      16-32 GB        9
256          */
257
258         mem = zone_managed_pages(zone) >> (27 - PAGE_SHIFT);
259
260         threshold = 2 * fls(num_online_cpus()) * (1 + fls(mem));
261
262         /*
263          * Maximum threshold is 125
264          */
265         threshold = min(125, threshold);
266
267         return threshold;
268 }
269
270 /*
271  * Refresh the thresholds for each zone.
272  */
273 void refresh_zone_stat_thresholds(void)
274 {
275         struct pglist_data *pgdat;
276         struct zone *zone;
277         int cpu;
278         int threshold;
279
280         /* Zero current pgdat thresholds */
281         for_each_online_pgdat(pgdat) {
282                 for_each_online_cpu(cpu) {
283                         per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold = 0;
284                 }
285         }
286
287         for_each_populated_zone(zone) {
288                 struct pglist_data *pgdat = zone->zone_pgdat;
289                 unsigned long max_drift, tolerate_drift;
290
291                 threshold = calculate_normal_threshold(zone);
292
293                 for_each_online_cpu(cpu) {
294                         int pgdat_threshold;
295
296                         per_cpu_ptr(zone->per_cpu_zonestats, cpu)->stat_threshold
297                                                         = threshold;
298
299                         /* Base nodestat threshold on the largest populated zone. */
300                         pgdat_threshold = per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold;
301                         per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold
302                                 = max(threshold, pgdat_threshold);
303                 }
304
305                 /*
306                  * Only set percpu_drift_mark if there is a danger that
307                  * NR_FREE_PAGES reports the low watermark is ok when in fact
308                  * the min watermark could be breached by an allocation
309                  */
310                 tolerate_drift = low_wmark_pages(zone) - min_wmark_pages(zone);
311                 max_drift = num_online_cpus() * threshold;
312                 if (max_drift > tolerate_drift)
313                         zone->percpu_drift_mark = high_wmark_pages(zone) +
314                                         max_drift;
315         }
316 }
317
318 void set_pgdat_percpu_threshold(pg_data_t *pgdat,
319                                 int (*calculate_pressure)(struct zone *))
320 {
321         struct zone *zone;
322         int cpu;
323         int threshold;
324         int i;
325
326         for (i = 0; i < pgdat->nr_zones; i++) {
327                 zone = &pgdat->node_zones[i];
328                 if (!zone->percpu_drift_mark)
329                         continue;
330
331                 threshold = (*calculate_pressure)(zone);
332                 for_each_online_cpu(cpu)
333                         per_cpu_ptr(zone->per_cpu_zonestats, cpu)->stat_threshold
334                                                         = threshold;
335         }
336 }
337
338 /*
339  * For use when we know that interrupts are disabled,
340  * or when we know that preemption is disabled and that
341  * particular counter cannot be updated from interrupt context.
342  */
343 void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
344                            long delta)
345 {
346         struct per_cpu_zonestat __percpu *pcp = zone->per_cpu_zonestats;
347         s8 __percpu *p = pcp->vm_stat_diff + item;
348         long x;
349         long t;
350
351         /*
352          * Accurate vmstat updates require a RMW. On !PREEMPT_RT kernels,
353          * atomicity is provided by IRQs being disabled -- either explicitly
354          * or via local_lock_irq. On PREEMPT_RT, local_lock_irq only disables
355          * CPU migrations and preemption potentially corrupts a counter so
356          * disable preemption.
357          */
358         if (IS_ENABLED(CONFIG_PREEMPT_RT))
359                 preempt_disable();
360
361         x = delta + __this_cpu_read(*p);
362
363         t = __this_cpu_read(pcp->stat_threshold);
364
365         if (unlikely(abs(x) > t)) {
366                 zone_page_state_add(x, zone, item);
367                 x = 0;
368         }
369         __this_cpu_write(*p, x);
370
371         if (IS_ENABLED(CONFIG_PREEMPT_RT))
372                 preempt_enable();
373 }
374 EXPORT_SYMBOL(__mod_zone_page_state);
375
376 void __mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
377                                 long delta)
378 {
379         struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
380         s8 __percpu *p = pcp->vm_node_stat_diff + item;
381         long x;
382         long t;
383
384         if (vmstat_item_in_bytes(item)) {
385                 /*
386                  * Only cgroups use subpage accounting right now; at
387                  * the global level, these items still change in
388                  * multiples of whole pages. Store them as pages
389                  * internally to keep the per-cpu counters compact.
390                  */
391                 VM_WARN_ON_ONCE(delta & (PAGE_SIZE - 1));
392                 delta >>= PAGE_SHIFT;
393         }
394
395         /* See __mod_node_page_state */
396         if (IS_ENABLED(CONFIG_PREEMPT_RT))
397                 preempt_disable();
398
399         x = delta + __this_cpu_read(*p);
400
401         t = __this_cpu_read(pcp->stat_threshold);
402
403         if (unlikely(abs(x) > t)) {
404                 node_page_state_add(x, pgdat, item);
405                 x = 0;
406         }
407         __this_cpu_write(*p, x);
408
409         if (IS_ENABLED(CONFIG_PREEMPT_RT))
410                 preempt_enable();
411 }
412 EXPORT_SYMBOL(__mod_node_page_state);
413
414 /*
415  * Optimized increment and decrement functions.
416  *
417  * These are only for a single page and therefore can take a struct page *
418  * argument instead of struct zone *. This allows the inclusion of the code
419  * generated for page_zone(page) into the optimized functions.
420  *
421  * No overflow check is necessary and therefore the differential can be
422  * incremented or decremented in place which may allow the compilers to
423  * generate better code.
424  * The increment or decrement is known and therefore one boundary check can
425  * be omitted.
426  *
427  * NOTE: These functions are very performance sensitive. Change only
428  * with care.
429  *
430  * Some processors have inc/dec instructions that are atomic vs an interrupt.
431  * However, the code must first determine the differential location in a zone
432  * based on the processor number and then inc/dec the counter. There is no
433  * guarantee without disabling preemption that the processor will not change
434  * in between and therefore the atomicity vs. interrupt cannot be exploited
435  * in a useful way here.
436  */
437 void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
438 {
439         struct per_cpu_zonestat __percpu *pcp = zone->per_cpu_zonestats;
440         s8 __percpu *p = pcp->vm_stat_diff + item;
441         s8 v, t;
442
443         /* See __mod_node_page_state */
444         if (IS_ENABLED(CONFIG_PREEMPT_RT))
445                 preempt_disable();
446
447         v = __this_cpu_inc_return(*p);
448         t = __this_cpu_read(pcp->stat_threshold);
449         if (unlikely(v > t)) {
450                 s8 overstep = t >> 1;
451
452                 zone_page_state_add(v + overstep, zone, item);
453                 __this_cpu_write(*p, -overstep);
454         }
455
456         if (IS_ENABLED(CONFIG_PREEMPT_RT))
457                 preempt_enable();
458 }
459
460 void __inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
461 {
462         struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
463         s8 __percpu *p = pcp->vm_node_stat_diff + item;
464         s8 v, t;
465
466         VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
467
468         /* See __mod_node_page_state */
469         if (IS_ENABLED(CONFIG_PREEMPT_RT))
470                 preempt_disable();
471
472         v = __this_cpu_inc_return(*p);
473         t = __this_cpu_read(pcp->stat_threshold);
474         if (unlikely(v > t)) {
475                 s8 overstep = t >> 1;
476
477                 node_page_state_add(v + overstep, pgdat, item);
478                 __this_cpu_write(*p, -overstep);
479         }
480
481         if (IS_ENABLED(CONFIG_PREEMPT_RT))
482                 preempt_enable();
483 }
484
485 void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
486 {
487         __inc_zone_state(page_zone(page), item);
488 }
489 EXPORT_SYMBOL(__inc_zone_page_state);
490
491 void __inc_node_page_state(struct page *page, enum node_stat_item item)
492 {
493         __inc_node_state(page_pgdat(page), item);
494 }
495 EXPORT_SYMBOL(__inc_node_page_state);
496
497 void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
498 {
499         struct per_cpu_zonestat __percpu *pcp = zone->per_cpu_zonestats;
500         s8 __percpu *p = pcp->vm_stat_diff + item;
501         s8 v, t;
502
503         /* See __mod_node_page_state */
504         if (IS_ENABLED(CONFIG_PREEMPT_RT))
505                 preempt_disable();
506
507         v = __this_cpu_dec_return(*p);
508         t = __this_cpu_read(pcp->stat_threshold);
509         if (unlikely(v < - t)) {
510                 s8 overstep = t >> 1;
511
512                 zone_page_state_add(v - overstep, zone, item);
513                 __this_cpu_write(*p, overstep);
514         }
515
516         if (IS_ENABLED(CONFIG_PREEMPT_RT))
517                 preempt_enable();
518 }
519
520 void __dec_node_state(struct pglist_data *pgdat, enum node_stat_item item)
521 {
522         struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
523         s8 __percpu *p = pcp->vm_node_stat_diff + item;
524         s8 v, t;
525
526         VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
527
528         /* See __mod_node_page_state */
529         if (IS_ENABLED(CONFIG_PREEMPT_RT))
530                 preempt_disable();
531
532         v = __this_cpu_dec_return(*p);
533         t = __this_cpu_read(pcp->stat_threshold);
534         if (unlikely(v < - t)) {
535                 s8 overstep = t >> 1;
536
537                 node_page_state_add(v - overstep, pgdat, item);
538                 __this_cpu_write(*p, overstep);
539         }
540
541         if (IS_ENABLED(CONFIG_PREEMPT_RT))
542                 preempt_enable();
543 }
544
545 void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
546 {
547         __dec_zone_state(page_zone(page), item);
548 }
549 EXPORT_SYMBOL(__dec_zone_page_state);
550
551 void __dec_node_page_state(struct page *page, enum node_stat_item item)
552 {
553         __dec_node_state(page_pgdat(page), item);
554 }
555 EXPORT_SYMBOL(__dec_node_page_state);
556
557 #ifdef CONFIG_HAVE_CMPXCHG_LOCAL
558 /*
559  * If we have cmpxchg_local support then we do not need to incur the overhead
560  * that comes with local_irq_save/restore if we use this_cpu_cmpxchg.
561  *
562  * mod_state() modifies the zone counter state through atomic per cpu
563  * operations.
564  *
565  * Overstep mode specifies how overstep should handled:
566  *     0       No overstepping
567  *     1       Overstepping half of threshold
568  *     -1      Overstepping minus half of threshold
569 */
570 static inline void mod_zone_state(struct zone *zone,
571        enum zone_stat_item item, long delta, int overstep_mode)
572 {
573         struct per_cpu_zonestat __percpu *pcp = zone->per_cpu_zonestats;
574         s8 __percpu *p = pcp->vm_stat_diff + item;
575         long o, n, t, z;
576
577         do {
578                 z = 0;  /* overflow to zone counters */
579
580                 /*
581                  * The fetching of the stat_threshold is racy. We may apply
582                  * a counter threshold to the wrong the cpu if we get
583                  * rescheduled while executing here. However, the next
584                  * counter update will apply the threshold again and
585                  * therefore bring the counter under the threshold again.
586                  *
587                  * Most of the time the thresholds are the same anyways
588                  * for all cpus in a zone.
589                  */
590                 t = this_cpu_read(pcp->stat_threshold);
591
592                 o = this_cpu_read(*p);
593                 n = delta + o;
594
595                 if (abs(n) > t) {
596                         int os = overstep_mode * (t >> 1) ;
597
598                         /* Overflow must be added to zone counters */
599                         z = n + os;
600                         n = -os;
601                 }
602         } while (this_cpu_cmpxchg(*p, o, n) != o);
603
604         if (z)
605                 zone_page_state_add(z, zone, item);
606 }
607
608 void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
609                          long delta)
610 {
611         mod_zone_state(zone, item, delta, 0);
612 }
613 EXPORT_SYMBOL(mod_zone_page_state);
614
615 void inc_zone_page_state(struct page *page, enum zone_stat_item item)
616 {
617         mod_zone_state(page_zone(page), item, 1, 1);
618 }
619 EXPORT_SYMBOL(inc_zone_page_state);
620
621 void dec_zone_page_state(struct page *page, enum zone_stat_item item)
622 {
623         mod_zone_state(page_zone(page), item, -1, -1);
624 }
625 EXPORT_SYMBOL(dec_zone_page_state);
626
627 static inline void mod_node_state(struct pglist_data *pgdat,
628        enum node_stat_item item, int delta, int overstep_mode)
629 {
630         struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
631         s8 __percpu *p = pcp->vm_node_stat_diff + item;
632         long o, n, t, z;
633
634         if (vmstat_item_in_bytes(item)) {
635                 /*
636                  * Only cgroups use subpage accounting right now; at
637                  * the global level, these items still change in
638                  * multiples of whole pages. Store them as pages
639                  * internally to keep the per-cpu counters compact.
640                  */
641                 VM_WARN_ON_ONCE(delta & (PAGE_SIZE - 1));
642                 delta >>= PAGE_SHIFT;
643         }
644
645         do {
646                 z = 0;  /* overflow to node counters */
647
648                 /*
649                  * The fetching of the stat_threshold is racy. We may apply
650                  * a counter threshold to the wrong the cpu if we get
651                  * rescheduled while executing here. However, the next
652                  * counter update will apply the threshold again and
653                  * therefore bring the counter under the threshold again.
654                  *
655                  * Most of the time the thresholds are the same anyways
656                  * for all cpus in a node.
657                  */
658                 t = this_cpu_read(pcp->stat_threshold);
659
660                 o = this_cpu_read(*p);
661                 n = delta + o;
662
663                 if (abs(n) > t) {
664                         int os = overstep_mode * (t >> 1) ;
665
666                         /* Overflow must be added to node counters */
667                         z = n + os;
668                         n = -os;
669                 }
670         } while (this_cpu_cmpxchg(*p, o, n) != o);
671
672         if (z)
673                 node_page_state_add(z, pgdat, item);
674 }
675
676 void mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
677                                         long delta)
678 {
679         mod_node_state(pgdat, item, delta, 0);
680 }
681 EXPORT_SYMBOL(mod_node_page_state);
682
683 void inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
684 {
685         mod_node_state(pgdat, item, 1, 1);
686 }
687
688 void inc_node_page_state(struct page *page, enum node_stat_item item)
689 {
690         mod_node_state(page_pgdat(page), item, 1, 1);
691 }
692 EXPORT_SYMBOL(inc_node_page_state);
693
694 void dec_node_page_state(struct page *page, enum node_stat_item item)
695 {
696         mod_node_state(page_pgdat(page), item, -1, -1);
697 }
698 EXPORT_SYMBOL(dec_node_page_state);
699 #else
700 /*
701  * Use interrupt disable to serialize counter updates
702  */
703 void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
704                          long delta)
705 {
706         unsigned long flags;
707
708         local_irq_save(flags);
709         __mod_zone_page_state(zone, item, delta);
710         local_irq_restore(flags);
711 }
712 EXPORT_SYMBOL(mod_zone_page_state);
713
714 void inc_zone_page_state(struct page *page, enum zone_stat_item item)
715 {
716         unsigned long flags;
717         struct zone *zone;
718
719         zone = page_zone(page);
720         local_irq_save(flags);
721         __inc_zone_state(zone, item);
722         local_irq_restore(flags);
723 }
724 EXPORT_SYMBOL(inc_zone_page_state);
725
726 void dec_zone_page_state(struct page *page, enum zone_stat_item item)
727 {
728         unsigned long flags;
729
730         local_irq_save(flags);
731         __dec_zone_page_state(page, item);
732         local_irq_restore(flags);
733 }
734 EXPORT_SYMBOL(dec_zone_page_state);
735
736 void inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
737 {
738         unsigned long flags;
739
740         local_irq_save(flags);
741         __inc_node_state(pgdat, item);
742         local_irq_restore(flags);
743 }
744 EXPORT_SYMBOL(inc_node_state);
745
746 void mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
747                                         long delta)
748 {
749         unsigned long flags;
750
751         local_irq_save(flags);
752         __mod_node_page_state(pgdat, item, delta);
753         local_irq_restore(flags);
754 }
755 EXPORT_SYMBOL(mod_node_page_state);
756
757 void inc_node_page_state(struct page *page, enum node_stat_item item)
758 {
759         unsigned long flags;
760         struct pglist_data *pgdat;
761
762         pgdat = page_pgdat(page);
763         local_irq_save(flags);
764         __inc_node_state(pgdat, item);
765         local_irq_restore(flags);
766 }
767 EXPORT_SYMBOL(inc_node_page_state);
768
769 void dec_node_page_state(struct page *page, enum node_stat_item item)
770 {
771         unsigned long flags;
772
773         local_irq_save(flags);
774         __dec_node_page_state(page, item);
775         local_irq_restore(flags);
776 }
777 EXPORT_SYMBOL(dec_node_page_state);
778 #endif
779
780 /*
781  * Fold a differential into the global counters.
782  * Returns the number of counters updated.
783  */
784 static int fold_diff(int *zone_diff, int *node_diff)
785 {
786         int i;
787         int changes = 0;
788
789         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
790                 if (zone_diff[i]) {
791                         atomic_long_add(zone_diff[i], &vm_zone_stat[i]);
792                         changes++;
793         }
794
795         for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
796                 if (node_diff[i]) {
797                         atomic_long_add(node_diff[i], &vm_node_stat[i]);
798                         changes++;
799         }
800         return changes;
801 }
802
803 /*
804  * Update the zone counters for the current cpu.
805  *
806  * Note that refresh_cpu_vm_stats strives to only access
807  * node local memory. The per cpu pagesets on remote zones are placed
808  * in the memory local to the processor using that pageset. So the
809  * loop over all zones will access a series of cachelines local to
810  * the processor.
811  *
812  * The call to zone_page_state_add updates the cachelines with the
813  * statistics in the remote zone struct as well as the global cachelines
814  * with the global counters. These could cause remote node cache line
815  * bouncing and will have to be only done when necessary.
816  *
817  * The function returns the number of global counters updated.
818  */
819 static int refresh_cpu_vm_stats(bool do_pagesets)
820 {
821         struct pglist_data *pgdat;
822         struct zone *zone;
823         int i;
824         int global_zone_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
825         int global_node_diff[NR_VM_NODE_STAT_ITEMS] = { 0, };
826         int changes = 0;
827
828         for_each_populated_zone(zone) {
829                 struct per_cpu_zonestat __percpu *pzstats = zone->per_cpu_zonestats;
830 #ifdef CONFIG_NUMA
831                 struct per_cpu_pages __percpu *pcp = zone->per_cpu_pageset;
832 #endif
833
834                 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
835                         int v;
836
837                         v = this_cpu_xchg(pzstats->vm_stat_diff[i], 0);
838                         if (v) {
839
840                                 atomic_long_add(v, &zone->vm_stat[i]);
841                                 global_zone_diff[i] += v;
842 #ifdef CONFIG_NUMA
843                                 /* 3 seconds idle till flush */
844                                 __this_cpu_write(pcp->expire, 3);
845 #endif
846                         }
847                 }
848 #ifdef CONFIG_NUMA
849
850                 if (do_pagesets) {
851                         cond_resched();
852                         /*
853                          * Deal with draining the remote pageset of this
854                          * processor
855                          *
856                          * Check if there are pages remaining in this pageset
857                          * if not then there is nothing to expire.
858                          */
859                         if (!__this_cpu_read(pcp->expire) ||
860                                !__this_cpu_read(pcp->count))
861                                 continue;
862
863                         /*
864                          * We never drain zones local to this processor.
865                          */
866                         if (zone_to_nid(zone) == numa_node_id()) {
867                                 __this_cpu_write(pcp->expire, 0);
868                                 continue;
869                         }
870
871                         if (__this_cpu_dec_return(pcp->expire))
872                                 continue;
873
874                         if (__this_cpu_read(pcp->count)) {
875                                 drain_zone_pages(zone, this_cpu_ptr(pcp));
876                                 changes++;
877                         }
878                 }
879 #endif
880         }
881
882         for_each_online_pgdat(pgdat) {
883                 struct per_cpu_nodestat __percpu *p = pgdat->per_cpu_nodestats;
884
885                 for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
886                         int v;
887
888                         v = this_cpu_xchg(p->vm_node_stat_diff[i], 0);
889                         if (v) {
890                                 atomic_long_add(v, &pgdat->vm_stat[i]);
891                                 global_node_diff[i] += v;
892                         }
893                 }
894         }
895
896         changes += fold_diff(global_zone_diff, global_node_diff);
897         return changes;
898 }
899
900 /*
901  * Fold the data for an offline cpu into the global array.
902  * There cannot be any access by the offline cpu and therefore
903  * synchronization is simplified.
904  */
905 void cpu_vm_stats_fold(int cpu)
906 {
907         struct pglist_data *pgdat;
908         struct zone *zone;
909         int i;
910         int global_zone_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
911         int global_node_diff[NR_VM_NODE_STAT_ITEMS] = { 0, };
912
913         for_each_populated_zone(zone) {
914                 struct per_cpu_zonestat *pzstats;
915
916                 pzstats = per_cpu_ptr(zone->per_cpu_zonestats, cpu);
917
918                 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
919                         if (pzstats->vm_stat_diff[i]) {
920                                 int v;
921
922                                 v = pzstats->vm_stat_diff[i];
923                                 pzstats->vm_stat_diff[i] = 0;
924                                 atomic_long_add(v, &zone->vm_stat[i]);
925                                 global_zone_diff[i] += v;
926                         }
927                 }
928 #ifdef CONFIG_NUMA
929                 for (i = 0; i < NR_VM_NUMA_EVENT_ITEMS; i++) {
930                         if (pzstats->vm_numa_event[i]) {
931                                 unsigned long v;
932
933                                 v = pzstats->vm_numa_event[i];
934                                 pzstats->vm_numa_event[i] = 0;
935                                 zone_numa_event_add(v, zone, i);
936                         }
937                 }
938 #endif
939         }
940
941         for_each_online_pgdat(pgdat) {
942                 struct per_cpu_nodestat *p;
943
944                 p = per_cpu_ptr(pgdat->per_cpu_nodestats, cpu);
945
946                 for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
947                         if (p->vm_node_stat_diff[i]) {
948                                 int v;
949
950                                 v = p->vm_node_stat_diff[i];
951                                 p->vm_node_stat_diff[i] = 0;
952                                 atomic_long_add(v, &pgdat->vm_stat[i]);
953                                 global_node_diff[i] += v;
954                         }
955         }
956
957         fold_diff(global_zone_diff, global_node_diff);
958 }
959
960 /*
961  * this is only called if !populated_zone(zone), which implies no other users of
962  * pset->vm_stat_diff[] exist.
963  */
964 void drain_zonestat(struct zone *zone, struct per_cpu_zonestat *pzstats)
965 {
966         unsigned long v;
967         int i;
968
969         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
970                 if (pzstats->vm_stat_diff[i]) {
971                         v = pzstats->vm_stat_diff[i];
972                         pzstats->vm_stat_diff[i] = 0;
973                         zone_page_state_add(v, zone, i);
974                 }
975         }
976
977 #ifdef CONFIG_NUMA
978         for (i = 0; i < NR_VM_NUMA_EVENT_ITEMS; i++) {
979                 if (pzstats->vm_numa_event[i]) {
980                         v = pzstats->vm_numa_event[i];
981                         pzstats->vm_numa_event[i] = 0;
982                         zone_numa_event_add(v, zone, i);
983                 }
984         }
985 #endif
986 }
987 #endif
988
989 #ifdef CONFIG_NUMA
990 /*
991  * Determine the per node value of a stat item. This function
992  * is called frequently in a NUMA machine, so try to be as
993  * frugal as possible.
994  */
995 unsigned long sum_zone_node_page_state(int node,
996                                  enum zone_stat_item item)
997 {
998         struct zone *zones = NODE_DATA(node)->node_zones;
999         int i;
1000         unsigned long count = 0;
1001
1002         for (i = 0; i < MAX_NR_ZONES; i++)
1003                 count += zone_page_state(zones + i, item);
1004
1005         return count;
1006 }
1007
1008 /* Determine the per node value of a numa stat item. */
1009 unsigned long sum_zone_numa_event_state(int node,
1010                                  enum numa_stat_item item)
1011 {
1012         struct zone *zones = NODE_DATA(node)->node_zones;
1013         unsigned long count = 0;
1014         int i;
1015
1016         for (i = 0; i < MAX_NR_ZONES; i++)
1017                 count += zone_numa_event_state(zones + i, item);
1018
1019         return count;
1020 }
1021
1022 /*
1023  * Determine the per node value of a stat item.
1024  */
1025 unsigned long node_page_state_pages(struct pglist_data *pgdat,
1026                                     enum node_stat_item item)
1027 {
1028         long x = atomic_long_read(&pgdat->vm_stat[item]);
1029 #ifdef CONFIG_SMP
1030         if (x < 0)
1031                 x = 0;
1032 #endif
1033         return x;
1034 }
1035
1036 unsigned long node_page_state(struct pglist_data *pgdat,
1037                               enum node_stat_item item)
1038 {
1039         VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
1040
1041         return node_page_state_pages(pgdat, item);
1042 }
1043 #endif
1044
1045 #ifdef CONFIG_COMPACTION
1046
1047 struct contig_page_info {
1048         unsigned long free_pages;
1049         unsigned long free_blocks_total;
1050         unsigned long free_blocks_suitable;
1051 };
1052
1053 /*
1054  * Calculate the number of free pages in a zone, how many contiguous
1055  * pages are free and how many are large enough to satisfy an allocation of
1056  * the target size. Note that this function makes no attempt to estimate
1057  * how many suitable free blocks there *might* be if MOVABLE pages were
1058  * migrated. Calculating that is possible, but expensive and can be
1059  * figured out from userspace
1060  */
1061 static void fill_contig_page_info(struct zone *zone,
1062                                 unsigned int suitable_order,
1063                                 struct contig_page_info *info)
1064 {
1065         unsigned int order;
1066
1067         info->free_pages = 0;
1068         info->free_blocks_total = 0;
1069         info->free_blocks_suitable = 0;
1070
1071         for (order = 0; order < MAX_ORDER; order++) {
1072                 unsigned long blocks;
1073
1074                 /*
1075                  * Count number of free blocks.
1076                  *
1077                  * Access to nr_free is lockless as nr_free is used only for
1078                  * diagnostic purposes. Use data_race to avoid KCSAN warning.
1079                  */
1080                 blocks = data_race(zone->free_area[order].nr_free);
1081                 info->free_blocks_total += blocks;
1082
1083                 /* Count free base pages */
1084                 info->free_pages += blocks << order;
1085
1086                 /* Count the suitable free blocks */
1087                 if (order >= suitable_order)
1088                         info->free_blocks_suitable += blocks <<
1089                                                 (order - suitable_order);
1090         }
1091 }
1092
1093 /*
1094  * A fragmentation index only makes sense if an allocation of a requested
1095  * size would fail. If that is true, the fragmentation index indicates
1096  * whether external fragmentation or a lack of memory was the problem.
1097  * The value can be used to determine if page reclaim or compaction
1098  * should be used
1099  */
1100 static int __fragmentation_index(unsigned int order, struct contig_page_info *info)
1101 {
1102         unsigned long requested = 1UL << order;
1103
1104         if (WARN_ON_ONCE(order >= MAX_ORDER))
1105                 return 0;
1106
1107         if (!info->free_blocks_total)
1108                 return 0;
1109
1110         /* Fragmentation index only makes sense when a request would fail */
1111         if (info->free_blocks_suitable)
1112                 return -1000;
1113
1114         /*
1115          * Index is between 0 and 1 so return within 3 decimal places
1116          *
1117          * 0 => allocation would fail due to lack of memory
1118          * 1 => allocation would fail due to fragmentation
1119          */
1120         return 1000 - div_u64( (1000+(div_u64(info->free_pages * 1000ULL, requested))), info->free_blocks_total);
1121 }
1122
1123 /*
1124  * Calculates external fragmentation within a zone wrt the given order.
1125  * It is defined as the percentage of pages found in blocks of size
1126  * less than 1 << order. It returns values in range [0, 100].
1127  */
1128 unsigned int extfrag_for_order(struct zone *zone, unsigned int order)
1129 {
1130         struct contig_page_info info;
1131
1132         fill_contig_page_info(zone, order, &info);
1133         if (info.free_pages == 0)
1134                 return 0;
1135
1136         return div_u64((info.free_pages -
1137                         (info.free_blocks_suitable << order)) * 100,
1138                         info.free_pages);
1139 }
1140
1141 /* Same as __fragmentation index but allocs contig_page_info on stack */
1142 int fragmentation_index(struct zone *zone, unsigned int order)
1143 {
1144         struct contig_page_info info;
1145
1146         fill_contig_page_info(zone, order, &info);
1147         return __fragmentation_index(order, &info);
1148 }
1149 #endif
1150
1151 #if defined(CONFIG_PROC_FS) || defined(CONFIG_SYSFS) || \
1152     defined(CONFIG_NUMA) || defined(CONFIG_MEMCG)
1153 #ifdef CONFIG_ZONE_DMA
1154 #define TEXT_FOR_DMA(xx) xx "_dma",
1155 #else
1156 #define TEXT_FOR_DMA(xx)
1157 #endif
1158
1159 #ifdef CONFIG_ZONE_DMA32
1160 #define TEXT_FOR_DMA32(xx) xx "_dma32",
1161 #else
1162 #define TEXT_FOR_DMA32(xx)
1163 #endif
1164
1165 #ifdef CONFIG_HIGHMEM
1166 #define TEXT_FOR_HIGHMEM(xx) xx "_high",
1167 #else
1168 #define TEXT_FOR_HIGHMEM(xx)
1169 #endif
1170
1171 #define TEXTS_FOR_ZONES(xx) TEXT_FOR_DMA(xx) TEXT_FOR_DMA32(xx) xx "_normal", \
1172                                         TEXT_FOR_HIGHMEM(xx) xx "_movable",
1173
1174 const char * const vmstat_text[] = {
1175         /* enum zone_stat_item counters */
1176         "nr_free_pages",
1177         "nr_zone_inactive_anon",
1178         "nr_zone_active_anon",
1179         "nr_zone_inactive_file",
1180         "nr_zone_active_file",
1181         "nr_zone_unevictable",
1182         "nr_zone_write_pending",
1183         "nr_mlock",
1184         "nr_bounce",
1185 #if IS_ENABLED(CONFIG_ZSMALLOC)
1186         "nr_zspages",
1187 #endif
1188         "nr_free_cma",
1189
1190         /* enum numa_stat_item counters */
1191 #ifdef CONFIG_NUMA
1192         "numa_hit",
1193         "numa_miss",
1194         "numa_foreign",
1195         "numa_interleave",
1196         "numa_local",
1197         "numa_other",
1198 #endif
1199
1200         /* enum node_stat_item counters */
1201         "nr_inactive_anon",
1202         "nr_active_anon",
1203         "nr_inactive_file",
1204         "nr_active_file",
1205         "nr_unevictable",
1206         "nr_slab_reclaimable",
1207         "nr_slab_unreclaimable",
1208         "nr_isolated_anon",
1209         "nr_isolated_file",
1210         "workingset_nodes",
1211         "workingset_refault_anon",
1212         "workingset_refault_file",
1213         "workingset_activate_anon",
1214         "workingset_activate_file",
1215         "workingset_restore_anon",
1216         "workingset_restore_file",
1217         "workingset_nodereclaim",
1218         "nr_anon_pages",
1219         "nr_mapped",
1220         "nr_file_pages",
1221         "nr_dirty",
1222         "nr_writeback",
1223         "nr_writeback_temp",
1224         "nr_shmem",
1225         "nr_shmem_hugepages",
1226         "nr_shmem_pmdmapped",
1227         "nr_file_hugepages",
1228         "nr_file_pmdmapped",
1229         "nr_anon_transparent_hugepages",
1230         "nr_vmscan_write",
1231         "nr_vmscan_immediate_reclaim",
1232         "nr_dirtied",
1233         "nr_written",
1234         "nr_throttled_written",
1235         "nr_kernel_misc_reclaimable",
1236         "nr_foll_pin_acquired",
1237         "nr_foll_pin_released",
1238         "nr_kernel_stack",
1239 #if IS_ENABLED(CONFIG_SHADOW_CALL_STACK)
1240         "nr_shadow_call_stack",
1241 #endif
1242         "nr_page_table_pages",
1243 #ifdef CONFIG_SWAP
1244         "nr_swapcached",
1245 #endif
1246 #ifdef CONFIG_NUMA_BALANCING
1247         "pgpromote_success",
1248 #endif
1249
1250         /* enum writeback_stat_item counters */
1251         "nr_dirty_threshold",
1252         "nr_dirty_background_threshold",
1253
1254 #if defined(CONFIG_VM_EVENT_COUNTERS) || defined(CONFIG_MEMCG)
1255         /* enum vm_event_item counters */
1256         "pgpgin",
1257         "pgpgout",
1258         "pswpin",
1259         "pswpout",
1260
1261         TEXTS_FOR_ZONES("pgalloc")
1262         TEXTS_FOR_ZONES("allocstall")
1263         TEXTS_FOR_ZONES("pgskip")
1264
1265         "pgfree",
1266         "pgactivate",
1267         "pgdeactivate",
1268         "pglazyfree",
1269
1270         "pgfault",
1271         "pgmajfault",
1272         "pglazyfreed",
1273
1274         "pgrefill",
1275         "pgreuse",
1276         "pgsteal_kswapd",
1277         "pgsteal_direct",
1278         "pgdemote_kswapd",
1279         "pgdemote_direct",
1280         "pgscan_kswapd",
1281         "pgscan_direct",
1282         "pgscan_direct_throttle",
1283         "pgscan_anon",
1284         "pgscan_file",
1285         "pgsteal_anon",
1286         "pgsteal_file",
1287
1288 #ifdef CONFIG_NUMA
1289         "zone_reclaim_failed",
1290 #endif
1291         "pginodesteal",
1292         "slabs_scanned",
1293         "kswapd_inodesteal",
1294         "kswapd_low_wmark_hit_quickly",
1295         "kswapd_high_wmark_hit_quickly",
1296         "pageoutrun",
1297
1298         "pgrotated",
1299
1300         "drop_pagecache",
1301         "drop_slab",
1302         "oom_kill",
1303
1304 #ifdef CONFIG_NUMA_BALANCING
1305         "numa_pte_updates",
1306         "numa_huge_pte_updates",
1307         "numa_hint_faults",
1308         "numa_hint_faults_local",
1309         "numa_pages_migrated",
1310 #endif
1311 #ifdef CONFIG_MIGRATION
1312         "pgmigrate_success",
1313         "pgmigrate_fail",
1314         "thp_migration_success",
1315         "thp_migration_fail",
1316         "thp_migration_split",
1317 #endif
1318 #ifdef CONFIG_COMPACTION
1319         "compact_migrate_scanned",
1320         "compact_free_scanned",
1321         "compact_isolated",
1322         "compact_stall",
1323         "compact_fail",
1324         "compact_success",
1325         "compact_daemon_wake",
1326         "compact_daemon_migrate_scanned",
1327         "compact_daemon_free_scanned",
1328 #endif
1329
1330 #ifdef CONFIG_HUGETLB_PAGE
1331         "htlb_buddy_alloc_success",
1332         "htlb_buddy_alloc_fail",
1333 #endif
1334 #ifdef CONFIG_CMA
1335         "cma_alloc_success",
1336         "cma_alloc_fail",
1337 #endif
1338         "unevictable_pgs_culled",
1339         "unevictable_pgs_scanned",
1340         "unevictable_pgs_rescued",
1341         "unevictable_pgs_mlocked",
1342         "unevictable_pgs_munlocked",
1343         "unevictable_pgs_cleared",
1344         "unevictable_pgs_stranded",
1345
1346 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1347         "thp_fault_alloc",
1348         "thp_fault_fallback",
1349         "thp_fault_fallback_charge",
1350         "thp_collapse_alloc",
1351         "thp_collapse_alloc_failed",
1352         "thp_file_alloc",
1353         "thp_file_fallback",
1354         "thp_file_fallback_charge",
1355         "thp_file_mapped",
1356         "thp_split_page",
1357         "thp_split_page_failed",
1358         "thp_deferred_split_page",
1359         "thp_split_pmd",
1360         "thp_scan_exceed_none_pte",
1361         "thp_scan_exceed_swap_pte",
1362         "thp_scan_exceed_share_pte",
1363 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
1364         "thp_split_pud",
1365 #endif
1366         "thp_zero_page_alloc",
1367         "thp_zero_page_alloc_failed",
1368         "thp_swpout",
1369         "thp_swpout_fallback",
1370 #endif
1371 #ifdef CONFIG_MEMORY_BALLOON
1372         "balloon_inflate",
1373         "balloon_deflate",
1374 #ifdef CONFIG_BALLOON_COMPACTION
1375         "balloon_migrate",
1376 #endif
1377 #endif /* CONFIG_MEMORY_BALLOON */
1378 #ifdef CONFIG_DEBUG_TLBFLUSH
1379         "nr_tlb_remote_flush",
1380         "nr_tlb_remote_flush_received",
1381         "nr_tlb_local_flush_all",
1382         "nr_tlb_local_flush_one",
1383 #endif /* CONFIG_DEBUG_TLBFLUSH */
1384
1385 #ifdef CONFIG_DEBUG_VM_VMACACHE
1386         "vmacache_find_calls",
1387         "vmacache_find_hits",
1388 #endif
1389 #ifdef CONFIG_SWAP
1390         "swap_ra",
1391         "swap_ra_hit",
1392 #ifdef CONFIG_KSM
1393         "ksm_swpin_copy",
1394 #endif
1395 #endif
1396 #ifdef CONFIG_KSM
1397         "cow_ksm",
1398 #endif
1399 #ifdef CONFIG_ZSWAP
1400         "zswpin",
1401         "zswpout",
1402 #endif
1403 #ifdef CONFIG_X86
1404         "direct_map_level2_splits",
1405         "direct_map_level3_splits",
1406 #endif
1407 #endif /* CONFIG_VM_EVENT_COUNTERS || CONFIG_MEMCG */
1408 };
1409 #endif /* CONFIG_PROC_FS || CONFIG_SYSFS || CONFIG_NUMA || CONFIG_MEMCG */
1410
1411 #if (defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)) || \
1412      defined(CONFIG_PROC_FS)
1413 static void *frag_start(struct seq_file *m, loff_t *pos)
1414 {
1415         pg_data_t *pgdat;
1416         loff_t node = *pos;
1417
1418         for (pgdat = first_online_pgdat();
1419              pgdat && node;
1420              pgdat = next_online_pgdat(pgdat))
1421                 --node;
1422
1423         return pgdat;
1424 }
1425
1426 static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
1427 {
1428         pg_data_t *pgdat = (pg_data_t *)arg;
1429
1430         (*pos)++;
1431         return next_online_pgdat(pgdat);
1432 }
1433
1434 static void frag_stop(struct seq_file *m, void *arg)
1435 {
1436 }
1437
1438 /*
1439  * Walk zones in a node and print using a callback.
1440  * If @assert_populated is true, only use callback for zones that are populated.
1441  */
1442 static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat,
1443                 bool assert_populated, bool nolock,
1444                 void (*print)(struct seq_file *m, pg_data_t *, struct zone *))
1445 {
1446         struct zone *zone;
1447         struct zone *node_zones = pgdat->node_zones;
1448         unsigned long flags;
1449
1450         for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
1451                 if (assert_populated && !populated_zone(zone))
1452                         continue;
1453
1454                 if (!nolock)
1455                         spin_lock_irqsave(&zone->lock, flags);
1456                 print(m, pgdat, zone);
1457                 if (!nolock)
1458                         spin_unlock_irqrestore(&zone->lock, flags);
1459         }
1460 }
1461 #endif
1462
1463 #ifdef CONFIG_PROC_FS
1464 static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,
1465                                                 struct zone *zone)
1466 {
1467         int order;
1468
1469         seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
1470         for (order = 0; order < MAX_ORDER; ++order)
1471                 /*
1472                  * Access to nr_free is lockless as nr_free is used only for
1473                  * printing purposes. Use data_race to avoid KCSAN warning.
1474                  */
1475                 seq_printf(m, "%6lu ", data_race(zone->free_area[order].nr_free));
1476         seq_putc(m, '\n');
1477 }
1478
1479 /*
1480  * This walks the free areas for each zone.
1481  */
1482 static int frag_show(struct seq_file *m, void *arg)
1483 {
1484         pg_data_t *pgdat = (pg_data_t *)arg;
1485         walk_zones_in_node(m, pgdat, true, false, frag_show_print);
1486         return 0;
1487 }
1488
1489 static void pagetypeinfo_showfree_print(struct seq_file *m,
1490                                         pg_data_t *pgdat, struct zone *zone)
1491 {
1492         int order, mtype;
1493
1494         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++) {
1495                 seq_printf(m, "Node %4d, zone %8s, type %12s ",
1496                                         pgdat->node_id,
1497                                         zone->name,
1498                                         migratetype_names[mtype]);
1499                 for (order = 0; order < MAX_ORDER; ++order) {
1500                         unsigned long freecount = 0;
1501                         struct free_area *area;
1502                         struct list_head *curr;
1503                         bool overflow = false;
1504
1505                         area = &(zone->free_area[order]);
1506
1507                         list_for_each(curr, &area->free_list[mtype]) {
1508                                 /*
1509                                  * Cap the free_list iteration because it might
1510                                  * be really large and we are under a spinlock
1511                                  * so a long time spent here could trigger a
1512                                  * hard lockup detector. Anyway this is a
1513                                  * debugging tool so knowing there is a handful
1514                                  * of pages of this order should be more than
1515                                  * sufficient.
1516                                  */
1517                                 if (++freecount >= 100000) {
1518                                         overflow = true;
1519                                         break;
1520                                 }
1521                         }
1522                         seq_printf(m, "%s%6lu ", overflow ? ">" : "", freecount);
1523                         spin_unlock_irq(&zone->lock);
1524                         cond_resched();
1525                         spin_lock_irq(&zone->lock);
1526                 }
1527                 seq_putc(m, '\n');
1528         }
1529 }
1530
1531 /* Print out the free pages at each order for each migatetype */
1532 static void pagetypeinfo_showfree(struct seq_file *m, void *arg)
1533 {
1534         int order;
1535         pg_data_t *pgdat = (pg_data_t *)arg;
1536
1537         /* Print header */
1538         seq_printf(m, "%-43s ", "Free pages count per migrate type at order");
1539         for (order = 0; order < MAX_ORDER; ++order)
1540                 seq_printf(m, "%6d ", order);
1541         seq_putc(m, '\n');
1542
1543         walk_zones_in_node(m, pgdat, true, false, pagetypeinfo_showfree_print);
1544 }
1545
1546 static void pagetypeinfo_showblockcount_print(struct seq_file *m,
1547                                         pg_data_t *pgdat, struct zone *zone)
1548 {
1549         int mtype;
1550         unsigned long pfn;
1551         unsigned long start_pfn = zone->zone_start_pfn;
1552         unsigned long end_pfn = zone_end_pfn(zone);
1553         unsigned long count[MIGRATE_TYPES] = { 0, };
1554
1555         for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
1556                 struct page *page;
1557
1558                 page = pfn_to_online_page(pfn);
1559                 if (!page)
1560                         continue;
1561
1562                 if (page_zone(page) != zone)
1563                         continue;
1564
1565                 mtype = get_pageblock_migratetype(page);
1566
1567                 if (mtype < MIGRATE_TYPES)
1568                         count[mtype]++;
1569         }
1570
1571         /* Print counts */
1572         seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
1573         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
1574                 seq_printf(m, "%12lu ", count[mtype]);
1575         seq_putc(m, '\n');
1576 }
1577
1578 /* Print out the number of pageblocks for each migratetype */
1579 static void pagetypeinfo_showblockcount(struct seq_file *m, void *arg)
1580 {
1581         int mtype;
1582         pg_data_t *pgdat = (pg_data_t *)arg;
1583
1584         seq_printf(m, "\n%-23s", "Number of blocks type ");
1585         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
1586                 seq_printf(m, "%12s ", migratetype_names[mtype]);
1587         seq_putc(m, '\n');
1588         walk_zones_in_node(m, pgdat, true, false,
1589                 pagetypeinfo_showblockcount_print);
1590 }
1591
1592 /*
1593  * Print out the number of pageblocks for each migratetype that contain pages
1594  * of other types. This gives an indication of how well fallbacks are being
1595  * contained by rmqueue_fallback(). It requires information from PAGE_OWNER
1596  * to determine what is going on
1597  */
1598 static void pagetypeinfo_showmixedcount(struct seq_file *m, pg_data_t *pgdat)
1599 {
1600 #ifdef CONFIG_PAGE_OWNER
1601         int mtype;
1602
1603         if (!static_branch_unlikely(&page_owner_inited))
1604                 return;
1605
1606         drain_all_pages(NULL);
1607
1608         seq_printf(m, "\n%-23s", "Number of mixed blocks ");
1609         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
1610                 seq_printf(m, "%12s ", migratetype_names[mtype]);
1611         seq_putc(m, '\n');
1612
1613         walk_zones_in_node(m, pgdat, true, true,
1614                 pagetypeinfo_showmixedcount_print);
1615 #endif /* CONFIG_PAGE_OWNER */
1616 }
1617
1618 /*
1619  * This prints out statistics in relation to grouping pages by mobility.
1620  * It is expensive to collect so do not constantly read the file.
1621  */
1622 static int pagetypeinfo_show(struct seq_file *m, void *arg)
1623 {
1624         pg_data_t *pgdat = (pg_data_t *)arg;
1625
1626         /* check memoryless node */
1627         if (!node_state(pgdat->node_id, N_MEMORY))
1628                 return 0;
1629
1630         seq_printf(m, "Page block order: %d\n", pageblock_order);
1631         seq_printf(m, "Pages per block:  %lu\n", pageblock_nr_pages);
1632         seq_putc(m, '\n');
1633         pagetypeinfo_showfree(m, pgdat);
1634         pagetypeinfo_showblockcount(m, pgdat);
1635         pagetypeinfo_showmixedcount(m, pgdat);
1636
1637         return 0;
1638 }
1639
1640 static const struct seq_operations fragmentation_op = {
1641         .start  = frag_start,
1642         .next   = frag_next,
1643         .stop   = frag_stop,
1644         .show   = frag_show,
1645 };
1646
1647 static const struct seq_operations pagetypeinfo_op = {
1648         .start  = frag_start,
1649         .next   = frag_next,
1650         .stop   = frag_stop,
1651         .show   = pagetypeinfo_show,
1652 };
1653
1654 static bool is_zone_first_populated(pg_data_t *pgdat, struct zone *zone)
1655 {
1656         int zid;
1657
1658         for (zid = 0; zid < MAX_NR_ZONES; zid++) {
1659                 struct zone *compare = &pgdat->node_zones[zid];
1660
1661                 if (populated_zone(compare))
1662                         return zone == compare;
1663         }
1664
1665         return false;
1666 }
1667
1668 static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
1669                                                         struct zone *zone)
1670 {
1671         int i;
1672         seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name);
1673         if (is_zone_first_populated(pgdat, zone)) {
1674                 seq_printf(m, "\n  per-node stats");
1675                 for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
1676                         unsigned long pages = node_page_state_pages(pgdat, i);
1677
1678                         if (vmstat_item_print_in_thp(i))
1679                                 pages /= HPAGE_PMD_NR;
1680                         seq_printf(m, "\n      %-12s %lu", node_stat_name(i),
1681                                    pages);
1682                 }
1683         }
1684         seq_printf(m,
1685                    "\n  pages free     %lu"
1686                    "\n        boost    %lu"
1687                    "\n        min      %lu"
1688                    "\n        low      %lu"
1689                    "\n        high     %lu"
1690                    "\n        spanned  %lu"
1691                    "\n        present  %lu"
1692                    "\n        managed  %lu"
1693                    "\n        cma      %lu",
1694                    zone_page_state(zone, NR_FREE_PAGES),
1695                    zone->watermark_boost,
1696                    min_wmark_pages(zone),
1697                    low_wmark_pages(zone),
1698                    high_wmark_pages(zone),
1699                    zone->spanned_pages,
1700                    zone->present_pages,
1701                    zone_managed_pages(zone),
1702                    zone_cma_pages(zone));
1703
1704         seq_printf(m,
1705                    "\n        protection: (%ld",
1706                    zone->lowmem_reserve[0]);
1707         for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++)
1708                 seq_printf(m, ", %ld", zone->lowmem_reserve[i]);
1709         seq_putc(m, ')');
1710
1711         /* If unpopulated, no other information is useful */
1712         if (!populated_zone(zone)) {
1713                 seq_putc(m, '\n');
1714                 return;
1715         }
1716
1717         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
1718                 seq_printf(m, "\n      %-12s %lu", zone_stat_name(i),
1719                            zone_page_state(zone, i));
1720
1721 #ifdef CONFIG_NUMA
1722         for (i = 0; i < NR_VM_NUMA_EVENT_ITEMS; i++)
1723                 seq_printf(m, "\n      %-12s %lu", numa_stat_name(i),
1724                            zone_numa_event_state(zone, i));
1725 #endif
1726
1727         seq_printf(m, "\n  pagesets");
1728         for_each_online_cpu(i) {
1729                 struct per_cpu_pages *pcp;
1730                 struct per_cpu_zonestat __maybe_unused *pzstats;
1731
1732                 pcp = per_cpu_ptr(zone->per_cpu_pageset, i);
1733                 seq_printf(m,
1734                            "\n    cpu: %i"
1735                            "\n              count: %i"
1736                            "\n              high:  %i"
1737                            "\n              batch: %i",
1738                            i,
1739                            pcp->count,
1740                            pcp->high,
1741                            pcp->batch);
1742 #ifdef CONFIG_SMP
1743                 pzstats = per_cpu_ptr(zone->per_cpu_zonestats, i);
1744                 seq_printf(m, "\n  vm stats threshold: %d",
1745                                 pzstats->stat_threshold);
1746 #endif
1747         }
1748         seq_printf(m,
1749                    "\n  node_unreclaimable:  %u"
1750                    "\n  start_pfn:           %lu",
1751                    pgdat->kswapd_failures >= MAX_RECLAIM_RETRIES,
1752                    zone->zone_start_pfn);
1753         seq_putc(m, '\n');
1754 }
1755
1756 /*
1757  * Output information about zones in @pgdat.  All zones are printed regardless
1758  * of whether they are populated or not: lowmem_reserve_ratio operates on the
1759  * set of all zones and userspace would not be aware of such zones if they are
1760  * suppressed here (zoneinfo displays the effect of lowmem_reserve_ratio).
1761  */
1762 static int zoneinfo_show(struct seq_file *m, void *arg)
1763 {
1764         pg_data_t *pgdat = (pg_data_t *)arg;
1765         walk_zones_in_node(m, pgdat, false, false, zoneinfo_show_print);
1766         return 0;
1767 }
1768
1769 static const struct seq_operations zoneinfo_op = {
1770         .start  = frag_start, /* iterate over all zones. The same as in
1771                                * fragmentation. */
1772         .next   = frag_next,
1773         .stop   = frag_stop,
1774         .show   = zoneinfo_show,
1775 };
1776
1777 #define NR_VMSTAT_ITEMS (NR_VM_ZONE_STAT_ITEMS + \
1778                          NR_VM_NUMA_EVENT_ITEMS + \
1779                          NR_VM_NODE_STAT_ITEMS + \
1780                          NR_VM_WRITEBACK_STAT_ITEMS + \
1781                          (IS_ENABLED(CONFIG_VM_EVENT_COUNTERS) ? \
1782                           NR_VM_EVENT_ITEMS : 0))
1783
1784 static void *vmstat_start(struct seq_file *m, loff_t *pos)
1785 {
1786         unsigned long *v;
1787         int i;
1788
1789         if (*pos >= NR_VMSTAT_ITEMS)
1790                 return NULL;
1791
1792         BUILD_BUG_ON(ARRAY_SIZE(vmstat_text) < NR_VMSTAT_ITEMS);
1793         fold_vm_numa_events();
1794         v = kmalloc_array(NR_VMSTAT_ITEMS, sizeof(unsigned long), GFP_KERNEL);
1795         m->private = v;
1796         if (!v)
1797                 return ERR_PTR(-ENOMEM);
1798         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
1799                 v[i] = global_zone_page_state(i);
1800         v += NR_VM_ZONE_STAT_ITEMS;
1801
1802 #ifdef CONFIG_NUMA
1803         for (i = 0; i < NR_VM_NUMA_EVENT_ITEMS; i++)
1804                 v[i] = global_numa_event_state(i);
1805         v += NR_VM_NUMA_EVENT_ITEMS;
1806 #endif
1807
1808         for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
1809                 v[i] = global_node_page_state_pages(i);
1810                 if (vmstat_item_print_in_thp(i))
1811                         v[i] /= HPAGE_PMD_NR;
1812         }
1813         v += NR_VM_NODE_STAT_ITEMS;
1814
1815         global_dirty_limits(v + NR_DIRTY_BG_THRESHOLD,
1816                             v + NR_DIRTY_THRESHOLD);
1817         v += NR_VM_WRITEBACK_STAT_ITEMS;
1818
1819 #ifdef CONFIG_VM_EVENT_COUNTERS
1820         all_vm_events(v);
1821         v[PGPGIN] /= 2;         /* sectors -> kbytes */
1822         v[PGPGOUT] /= 2;
1823 #endif
1824         return (unsigned long *)m->private + *pos;
1825 }
1826
1827 static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)
1828 {
1829         (*pos)++;
1830         if (*pos >= NR_VMSTAT_ITEMS)
1831                 return NULL;
1832         return (unsigned long *)m->private + *pos;
1833 }
1834
1835 static int vmstat_show(struct seq_file *m, void *arg)
1836 {
1837         unsigned long *l = arg;
1838         unsigned long off = l - (unsigned long *)m->private;
1839
1840         seq_puts(m, vmstat_text[off]);
1841         seq_put_decimal_ull(m, " ", *l);
1842         seq_putc(m, '\n');
1843
1844         if (off == NR_VMSTAT_ITEMS - 1) {
1845                 /*
1846                  * We've come to the end - add any deprecated counters to avoid
1847                  * breaking userspace which might depend on them being present.
1848                  */
1849                 seq_puts(m, "nr_unstable 0\n");
1850         }
1851         return 0;
1852 }
1853
1854 static void vmstat_stop(struct seq_file *m, void *arg)
1855 {
1856         kfree(m->private);
1857         m->private = NULL;
1858 }
1859
1860 static const struct seq_operations vmstat_op = {
1861         .start  = vmstat_start,
1862         .next   = vmstat_next,
1863         .stop   = vmstat_stop,
1864         .show   = vmstat_show,
1865 };
1866 #endif /* CONFIG_PROC_FS */
1867
1868 #ifdef CONFIG_SMP
1869 static DEFINE_PER_CPU(struct delayed_work, vmstat_work);
1870 int sysctl_stat_interval __read_mostly = HZ;
1871
1872 #ifdef CONFIG_PROC_FS
1873 static void refresh_vm_stats(struct work_struct *work)
1874 {
1875         refresh_cpu_vm_stats(true);
1876 }
1877
1878 int vmstat_refresh(struct ctl_table *table, int write,
1879                    void *buffer, size_t *lenp, loff_t *ppos)
1880 {
1881         long val;
1882         int err;
1883         int i;
1884
1885         /*
1886          * The regular update, every sysctl_stat_interval, may come later
1887          * than expected: leaving a significant amount in per_cpu buckets.
1888          * This is particularly misleading when checking a quantity of HUGE
1889          * pages, immediately after running a test.  /proc/sys/vm/stat_refresh,
1890          * which can equally be echo'ed to or cat'ted from (by root),
1891          * can be used to update the stats just before reading them.
1892          *
1893          * Oh, and since global_zone_page_state() etc. are so careful to hide
1894          * transiently negative values, report an error here if any of
1895          * the stats is negative, so we know to go looking for imbalance.
1896          */
1897         err = schedule_on_each_cpu(refresh_vm_stats);
1898         if (err)
1899                 return err;
1900         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
1901                 /*
1902                  * Skip checking stats known to go negative occasionally.
1903                  */
1904                 switch (i) {
1905                 case NR_ZONE_WRITE_PENDING:
1906                 case NR_FREE_CMA_PAGES:
1907                         continue;
1908                 }
1909                 val = atomic_long_read(&vm_zone_stat[i]);
1910                 if (val < 0) {
1911                         pr_warn("%s: %s %ld\n",
1912                                 __func__, zone_stat_name(i), val);
1913                 }
1914         }
1915         for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
1916                 /*
1917                  * Skip checking stats known to go negative occasionally.
1918                  */
1919                 switch (i) {
1920                 case NR_WRITEBACK:
1921                         continue;
1922                 }
1923                 val = atomic_long_read(&vm_node_stat[i]);
1924                 if (val < 0) {
1925                         pr_warn("%s: %s %ld\n",
1926                                 __func__, node_stat_name(i), val);
1927                 }
1928         }
1929         if (write)
1930                 *ppos += *lenp;
1931         else
1932                 *lenp = 0;
1933         return 0;
1934 }
1935 #endif /* CONFIG_PROC_FS */
1936
1937 static void vmstat_update(struct work_struct *w)
1938 {
1939         if (refresh_cpu_vm_stats(true)) {
1940                 /*
1941                  * Counters were updated so we expect more updates
1942                  * to occur in the future. Keep on running the
1943                  * update worker thread.
1944                  */
1945                 queue_delayed_work_on(smp_processor_id(), mm_percpu_wq,
1946                                 this_cpu_ptr(&vmstat_work),
1947                                 round_jiffies_relative(sysctl_stat_interval));
1948         }
1949 }
1950
1951 /*
1952  * Check if the diffs for a certain cpu indicate that
1953  * an update is needed.
1954  */
1955 static bool need_update(int cpu)
1956 {
1957         pg_data_t *last_pgdat = NULL;
1958         struct zone *zone;
1959
1960         for_each_populated_zone(zone) {
1961                 struct per_cpu_zonestat *pzstats = per_cpu_ptr(zone->per_cpu_zonestats, cpu);
1962                 struct per_cpu_nodestat *n;
1963
1964                 /*
1965                  * The fast way of checking if there are any vmstat diffs.
1966                  */
1967                 if (memchr_inv(pzstats->vm_stat_diff, 0, sizeof(pzstats->vm_stat_diff)))
1968                         return true;
1969
1970                 if (last_pgdat == zone->zone_pgdat)
1971                         continue;
1972                 last_pgdat = zone->zone_pgdat;
1973                 n = per_cpu_ptr(zone->zone_pgdat->per_cpu_nodestats, cpu);
1974                 if (memchr_inv(n->vm_node_stat_diff, 0, sizeof(n->vm_node_stat_diff)))
1975                         return true;
1976         }
1977         return false;
1978 }
1979
1980 /*
1981  * Switch off vmstat processing and then fold all the remaining differentials
1982  * until the diffs stay at zero. The function is used by NOHZ and can only be
1983  * invoked when tick processing is not active.
1984  */
1985 void quiet_vmstat(void)
1986 {
1987         if (system_state != SYSTEM_RUNNING)
1988                 return;
1989
1990         if (!delayed_work_pending(this_cpu_ptr(&vmstat_work)))
1991                 return;
1992
1993         if (!need_update(smp_processor_id()))
1994                 return;
1995
1996         /*
1997          * Just refresh counters and do not care about the pending delayed
1998          * vmstat_update. It doesn't fire that often to matter and canceling
1999          * it would be too expensive from this path.
2000          * vmstat_shepherd will take care about that for us.
2001          */
2002         refresh_cpu_vm_stats(false);
2003 }
2004
2005 /*
2006  * Shepherd worker thread that checks the
2007  * differentials of processors that have their worker
2008  * threads for vm statistics updates disabled because of
2009  * inactivity.
2010  */
2011 static void vmstat_shepherd(struct work_struct *w);
2012
2013 static DECLARE_DEFERRABLE_WORK(shepherd, vmstat_shepherd);
2014
2015 static void vmstat_shepherd(struct work_struct *w)
2016 {
2017         int cpu;
2018
2019         cpus_read_lock();
2020         /* Check processors whose vmstat worker threads have been disabled */
2021         for_each_online_cpu(cpu) {
2022                 struct delayed_work *dw = &per_cpu(vmstat_work, cpu);
2023
2024                 if (!delayed_work_pending(dw) && need_update(cpu))
2025                         queue_delayed_work_on(cpu, mm_percpu_wq, dw, 0);
2026
2027                 cond_resched();
2028         }
2029         cpus_read_unlock();
2030
2031         schedule_delayed_work(&shepherd,
2032                 round_jiffies_relative(sysctl_stat_interval));
2033 }
2034
2035 static void __init start_shepherd_timer(void)
2036 {
2037         int cpu;
2038
2039         for_each_possible_cpu(cpu)
2040                 INIT_DEFERRABLE_WORK(per_cpu_ptr(&vmstat_work, cpu),
2041                         vmstat_update);
2042
2043         schedule_delayed_work(&shepherd,
2044                 round_jiffies_relative(sysctl_stat_interval));
2045 }
2046
2047 static void __init init_cpu_node_state(void)
2048 {
2049         int node;
2050
2051         for_each_online_node(node) {
2052                 if (!cpumask_empty(cpumask_of_node(node)))
2053                         node_set_state(node, N_CPU);
2054         }
2055 }
2056
2057 static int vmstat_cpu_online(unsigned int cpu)
2058 {
2059         refresh_zone_stat_thresholds();
2060
2061         if (!node_state(cpu_to_node(cpu), N_CPU)) {
2062                 node_set_state(cpu_to_node(cpu), N_CPU);
2063                 set_migration_target_nodes();
2064         }
2065
2066         return 0;
2067 }
2068
2069 static int vmstat_cpu_down_prep(unsigned int cpu)
2070 {
2071         cancel_delayed_work_sync(&per_cpu(vmstat_work, cpu));
2072         return 0;
2073 }
2074
2075 static int vmstat_cpu_dead(unsigned int cpu)
2076 {
2077         const struct cpumask *node_cpus;
2078         int node;
2079
2080         node = cpu_to_node(cpu);
2081
2082         refresh_zone_stat_thresholds();
2083         node_cpus = cpumask_of_node(node);
2084         if (!cpumask_empty(node_cpus))
2085                 return 0;
2086
2087         node_clear_state(node, N_CPU);
2088         set_migration_target_nodes();
2089
2090         return 0;
2091 }
2092
2093 #endif
2094
2095 struct workqueue_struct *mm_percpu_wq;
2096
2097 void __init init_mm_internals(void)
2098 {
2099         int ret __maybe_unused;
2100
2101         mm_percpu_wq = alloc_workqueue("mm_percpu_wq", WQ_MEM_RECLAIM, 0);
2102
2103 #ifdef CONFIG_SMP
2104         ret = cpuhp_setup_state_nocalls(CPUHP_MM_VMSTAT_DEAD, "mm/vmstat:dead",
2105                                         NULL, vmstat_cpu_dead);
2106         if (ret < 0)
2107                 pr_err("vmstat: failed to register 'dead' hotplug state\n");
2108
2109         ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "mm/vmstat:online",
2110                                         vmstat_cpu_online,
2111                                         vmstat_cpu_down_prep);
2112         if (ret < 0)
2113                 pr_err("vmstat: failed to register 'online' hotplug state\n");
2114
2115         cpus_read_lock();
2116         init_cpu_node_state();
2117         cpus_read_unlock();
2118
2119         start_shepherd_timer();
2120 #endif
2121         migrate_on_reclaim_init();
2122 #ifdef CONFIG_PROC_FS
2123         proc_create_seq("buddyinfo", 0444, NULL, &fragmentation_op);
2124         proc_create_seq("pagetypeinfo", 0400, NULL, &pagetypeinfo_op);
2125         proc_create_seq("vmstat", 0444, NULL, &vmstat_op);
2126         proc_create_seq("zoneinfo", 0444, NULL, &zoneinfo_op);
2127 #endif
2128 }
2129
2130 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)
2131
2132 /*
2133  * Return an index indicating how much of the available free memory is
2134  * unusable for an allocation of the requested size.
2135  */
2136 static int unusable_free_index(unsigned int order,
2137                                 struct contig_page_info *info)
2138 {
2139         /* No free memory is interpreted as all free memory is unusable */
2140         if (info->free_pages == 0)
2141                 return 1000;
2142
2143         /*
2144          * Index should be a value between 0 and 1. Return a value to 3
2145          * decimal places.
2146          *
2147          * 0 => no fragmentation
2148          * 1 => high fragmentation
2149          */
2150         return div_u64((info->free_pages - (info->free_blocks_suitable << order)) * 1000ULL, info->free_pages);
2151
2152 }
2153
2154 static void unusable_show_print(struct seq_file *m,
2155                                         pg_data_t *pgdat, struct zone *zone)
2156 {
2157         unsigned int order;
2158         int index;
2159         struct contig_page_info info;
2160
2161         seq_printf(m, "Node %d, zone %8s ",
2162                                 pgdat->node_id,
2163                                 zone->name);
2164         for (order = 0; order < MAX_ORDER; ++order) {
2165                 fill_contig_page_info(zone, order, &info);
2166                 index = unusable_free_index(order, &info);
2167                 seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
2168         }
2169
2170         seq_putc(m, '\n');
2171 }
2172
2173 /*
2174  * Display unusable free space index
2175  *
2176  * The unusable free space index measures how much of the available free
2177  * memory cannot be used to satisfy an allocation of a given size and is a
2178  * value between 0 and 1. The higher the value, the more of free memory is
2179  * unusable and by implication, the worse the external fragmentation is. This
2180  * can be expressed as a percentage by multiplying by 100.
2181  */
2182 static int unusable_show(struct seq_file *m, void *arg)
2183 {
2184         pg_data_t *pgdat = (pg_data_t *)arg;
2185
2186         /* check memoryless node */
2187         if (!node_state(pgdat->node_id, N_MEMORY))
2188                 return 0;
2189
2190         walk_zones_in_node(m, pgdat, true, false, unusable_show_print);
2191
2192         return 0;
2193 }
2194
2195 static const struct seq_operations unusable_sops = {
2196         .start  = frag_start,
2197         .next   = frag_next,
2198         .stop   = frag_stop,
2199         .show   = unusable_show,
2200 };
2201
2202 DEFINE_SEQ_ATTRIBUTE(unusable);
2203
2204 static void extfrag_show_print(struct seq_file *m,
2205                                         pg_data_t *pgdat, struct zone *zone)
2206 {
2207         unsigned int order;
2208         int index;
2209
2210         /* Alloc on stack as interrupts are disabled for zone walk */
2211         struct contig_page_info info;
2212
2213         seq_printf(m, "Node %d, zone %8s ",
2214                                 pgdat->node_id,
2215                                 zone->name);
2216         for (order = 0; order < MAX_ORDER; ++order) {
2217                 fill_contig_page_info(zone, order, &info);
2218                 index = __fragmentation_index(order, &info);
2219                 seq_printf(m, "%2d.%03d ", index / 1000, index % 1000);
2220         }
2221
2222         seq_putc(m, '\n');
2223 }
2224
2225 /*
2226  * Display fragmentation index for orders that allocations would fail for
2227  */
2228 static int extfrag_show(struct seq_file *m, void *arg)
2229 {
2230         pg_data_t *pgdat = (pg_data_t *)arg;
2231
2232         walk_zones_in_node(m, pgdat, true, false, extfrag_show_print);
2233
2234         return 0;
2235 }
2236
2237 static const struct seq_operations extfrag_sops = {
2238         .start  = frag_start,
2239         .next   = frag_next,
2240         .stop   = frag_stop,
2241         .show   = extfrag_show,
2242 };
2243
2244 DEFINE_SEQ_ATTRIBUTE(extfrag);
2245
2246 static int __init extfrag_debug_init(void)
2247 {
2248         struct dentry *extfrag_debug_root;
2249
2250         extfrag_debug_root = debugfs_create_dir("extfrag", NULL);
2251
2252         debugfs_create_file("unusable_index", 0444, extfrag_debug_root, NULL,
2253                             &unusable_fops);
2254
2255         debugfs_create_file("extfrag_index", 0444, extfrag_debug_root, NULL,
2256                             &extfrag_fops);
2257
2258         return 0;
2259 }
2260
2261 module_init(extfrag_debug_init);
2262 #endif