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_owner.h>
30 #include <linux/sched/isolation.h>
31
32 #include "internal.h"
33
34 #ifdef CONFIG_NUMA
35 int sysctl_vm_numa_stat = ENABLE_NUMA_STAT;
36
37 /* zero numa counters within a zone */
38 static void zero_zone_numa_counters(struct zone *zone)
39 {
40 int item, cpu;
41
42 for (item = 0; item < NR_VM_NUMA_EVENT_ITEMS; item++) {
43 atomic_long_set(&zone->vm_numa_event[item], 0);
44 for_each_online_cpu(cpu) {
45 per_cpu_ptr(zone->per_cpu_zonestats, cpu)->vm_numa_event[item]
46 = 0;
47 }
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_EVENT_ITEMS; item++)
66 atomic_long_set(&vm_numa_event[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(const struct ctl_table *table, int write,
78 void *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 cpus_read_lock();
133 sum_vm_events(ret);
134 cpus_read_unlock();
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_node_stat[NR_VM_NODE_STAT_ITEMS] __cacheline_aligned_in_smp;
164 atomic_long_t vm_numa_event[NR_VM_NUMA_EVENT_ITEMS] __cacheline_aligned_in_smp;
165 EXPORT_SYMBOL(vm_zone_stat);
166 EXPORT_SYMBOL(vm_node_stat);
167
168 #ifdef CONFIG_NUMA
169 static void fold_vm_zone_numa_events(struct zone *zone)
170 {
171 unsigned long zone_numa_events[NR_VM_NUMA_EVENT_ITEMS] = { 0, };
172 int cpu;
173 enum numa_stat_item item;
174
175 for_each_online_cpu(cpu) {
176 struct per_cpu_zonestat *pzstats;
177
178 pzstats = per_cpu_ptr(zone->per_cpu_zonestats, cpu);
179 for (item = 0; item < NR_VM_NUMA_EVENT_ITEMS; item++)
180 zone_numa_events[item] += xchg(&pzstats->vm_numa_event[item], 0);
181 }
182
183 for (item = 0; item < NR_VM_NUMA_EVENT_ITEMS; item++)
184 zone_numa_event_add(zone_numa_events[item], zone, item);
185 }
186
187 void fold_vm_numa_events(void)
188 {
189 struct zone *zone;
190
191 for_each_populated_zone(zone)
192 fold_vm_zone_numa_events(zone);
193 }
194 #endif
195
196 #ifdef CONFIG_SMP
197
198 int calculate_pressure_threshold(struct zone *zone)
199 {
200 int threshold;
201 int watermark_distance;
202
203 /*
204 * As vmstats are not up to date, there is drift between the estimated
205 * and real values. For high thresholds and a high number of CPUs, it
206 * is possible for the min watermark to be breached while the estimated
207 * value looks fine. The pressure threshold is a reduced value such
208 * that even the maximum amount of drift will not accidentally breach
209 * the min watermark
210 */
211 watermark_distance = low_wmark_pages(zone) - min_wmark_pages(zone);
212 threshold = max(1, (int)(watermark_distance / num_online_cpus()));
213
214 /*
215 * Maximum threshold is 125
216 */
217 threshold = min(125, threshold);
218
219 return threshold;
220 }
221
222 int calculate_normal_threshold(struct zone *zone)
223 {
224 int threshold;
225 int mem; /* memory in 128 MB units */
226
227 /*
228 * The threshold scales with the number of processors and the amount
229 * of memory per zone. More memory means that we can defer updates for
230 * longer, more processors could lead to more contention.
231 * fls() is used to have a cheap way of logarithmic scaling.
232 *
233 * Some sample thresholds:
234 *
235 * Threshold Processors (fls) Zonesize fls(mem)+1
236 * ------------------------------------------------------------------
237 * 8 1 1 0.9-1 GB 4
238 * 16 2 2 0.9-1 GB 4
239 * 20 2 2 1-2 GB 5
240 * 24 2 2 2-4 GB 6
241 * 28 2 2 4-8 GB 7
242 * 32 2 2 8-16 GB 8
243 * 4 2 2 <128M 1
244 * 30 4 3 2-4 GB 5
245 * 48 4 3 8-16 GB 8
246 * 32 8 4 1-2 GB 4
247 * 32 8 4 0.9-1GB 4
248 * 10 16 5 <128M 1
249 * 40 16 5 900M 4
250 * 70 64 7 2-4 GB 5
251 * 84 64 7 4-8 GB 6
252 * 108 512 9 4-8 GB 6
253 * 125 1024 10 8-16 GB 8
254 * 125 1024 10 16-32 GB 9
255 */
256
257 mem = zone_managed_pages(zone) >> (27 - PAGE_SHIFT);
258
259 threshold = 2 * fls(num_online_cpus()) * (1 + fls(mem));
260
261 /*
262 * Maximum threshold is 125
263 */
264 threshold = min(125, threshold);
265
266 return threshold;
267 }
268
269 /*
270 * Refresh the thresholds for each zone.
271 */
272 void refresh_zone_stat_thresholds(void)
273 {
274 struct pglist_data *pgdat;
275 struct zone *zone;
276 int cpu;
277 int threshold;
278
279 /* Zero current pgdat thresholds */
280 for_each_online_pgdat(pgdat) {
281 for_each_online_cpu(cpu) {
282 per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold = 0;
283 }
284 }
285
286 for_each_populated_zone(zone) {
287 struct pglist_data *pgdat = zone->zone_pgdat;
288 unsigned long max_drift, tolerate_drift;
289
290 threshold = calculate_normal_threshold(zone);
291
292 for_each_online_cpu(cpu) {
293 int pgdat_threshold;
294
295 per_cpu_ptr(zone->per_cpu_zonestats, cpu)->stat_threshold
296 = threshold;
297
298 /* Base nodestat threshold on the largest populated zone. */
299 pgdat_threshold = per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold;
300 per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold
301 = max(threshold, pgdat_threshold);
302 }
303
304 /*
305 * Only set percpu_drift_mark if there is a danger that
306 * NR_FREE_PAGES reports the low watermark is ok when in fact
307 * the min watermark could be breached by an allocation
308 */
309 tolerate_drift = low_wmark_pages(zone) - min_wmark_pages(zone);
310 max_drift = num_online_cpus() * threshold;
311 if (max_drift > tolerate_drift)
312 zone->percpu_drift_mark = high_wmark_pages(zone) +
313 max_drift;
314 }
315 }
316
317 void set_pgdat_percpu_threshold(pg_data_t *pgdat,
318 int (*calculate_pressure)(struct zone *))
319 {
320 struct zone *zone;
321 int cpu;
322 int threshold;
323 int i;
324
325 for (i = 0; i < pgdat->nr_zones; i++) {
326 zone = &pgdat->node_zones[i];
327 if (!zone->percpu_drift_mark)
328 continue;
329
330 threshold = (*calculate_pressure)(zone);
331 for_each_online_cpu(cpu)
332 per_cpu_ptr(zone->per_cpu_zonestats, cpu)->stat_threshold
333 = threshold;
334 }
335 }
336
337 /*
338 * For use when we know that interrupts are disabled,
339 * or when we know that preemption is disabled and that
340 * particular counter cannot be updated from interrupt context.
341 */
342 void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
343 long delta)
344 {
345 struct per_cpu_zonestat __percpu *pcp = zone->per_cpu_zonestats;
346 s8 __percpu *p = pcp->vm_stat_diff + item;
347 long x;
348 long t;
349
350 /*
351 * Accurate vmstat updates require a RMW. On !PREEMPT_RT kernels,
352 * atomicity is provided by IRQs being disabled -- either explicitly
353 * or via local_lock_irq. On PREEMPT_RT, local_lock_irq only disables
354 * CPU migrations and preemption potentially corrupts a counter so
355 * disable preemption.
356 */
357 preempt_disable_nested();
358
359 x = delta + __this_cpu_read(*p);
360
361 t = __this_cpu_read(pcp->stat_threshold);
362
363 if (unlikely(abs(x) > t)) {
364 zone_page_state_add(x, zone, item);
365 x = 0;
366 }
367 __this_cpu_write(*p, x);
368
369 preempt_enable_nested();
370 }
371 EXPORT_SYMBOL(__mod_zone_page_state);
372
373 void __mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
374 long delta)
375 {
376 struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
377 s8 __percpu *p = pcp->vm_node_stat_diff + item;
378 long x;
379 long t;
380
381 if (vmstat_item_in_bytes(item)) {
382 /*
383 * Only cgroups use subpage accounting right now; at
384 * the global level, these items still change in
385 * multiples of whole pages. Store them as pages
386 * internally to keep the per-cpu counters compact.
387 */
388 VM_WARN_ON_ONCE(delta & (PAGE_SIZE - 1));
389 delta >>= PAGE_SHIFT;
390 }
391
392 /* See __mod_node_page_state */
393 preempt_disable_nested();
394
395 x = delta + __this_cpu_read(*p);
396
397 t = __this_cpu_read(pcp->stat_threshold);
398
399 if (unlikely(abs(x) > t)) {
400 node_page_state_add(x, pgdat, item);
401 x = 0;
402 }
403 __this_cpu_write(*p, x);
404
405 preempt_enable_nested();
406 }
407 EXPORT_SYMBOL(__mod_node_page_state);
408
409 /*
410 * Optimized increment and decrement functions.
411 *
412 * These are only for a single page and therefore can take a struct page *
413 * argument instead of struct zone *. This allows the inclusion of the code
414 * generated for page_zone(page) into the optimized functions.
415 *
416 * No overflow check is necessary and therefore the differential can be
417 * incremented or decremented in place which may allow the compilers to
418 * generate better code.
419 * The increment or decrement is known and therefore one boundary check can
420 * be omitted.
421 *
422 * NOTE: These functions are very performance sensitive. Change only
423 * with care.
424 *
425 * Some processors have inc/dec instructions that are atomic vs an interrupt.
426 * However, the code must first determine the differential location in a zone
427 * based on the processor number and then inc/dec the counter. There is no
428 * guarantee without disabling preemption that the processor will not change
429 * in between and therefore the atomicity vs. interrupt cannot be exploited
430 * in a useful way here.
431 */
432 void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
433 {
434 struct per_cpu_zonestat __percpu *pcp = zone->per_cpu_zonestats;
435 s8 __percpu *p = pcp->vm_stat_diff + item;
436 s8 v, t;
437
438 /* See __mod_node_page_state */
439 preempt_disable_nested();
440
441 v = __this_cpu_inc_return(*p);
442 t = __this_cpu_read(pcp->stat_threshold);
443 if (unlikely(v > t)) {
444 s8 overstep = t >> 1;
445
446 zone_page_state_add(v + overstep, zone, item);
447 __this_cpu_write(*p, -overstep);
448 }
449
450 preempt_enable_nested();
451 }
452
453 void __inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
454 {
455 struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
456 s8 __percpu *p = pcp->vm_node_stat_diff + item;
457 s8 v, t;
458
459 VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
460
461 /* See __mod_node_page_state */
462 preempt_disable_nested();
463
464 v = __this_cpu_inc_return(*p);
465 t = __this_cpu_read(pcp->stat_threshold);
466 if (unlikely(v > t)) {
467 s8 overstep = t >> 1;
468
469 node_page_state_add(v + overstep, pgdat, item);
470 __this_cpu_write(*p, -overstep);
471 }
472
473 preempt_enable_nested();
474 }
475
476 void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
477 {
478 __inc_zone_state(page_zone(page), item);
479 }
480 EXPORT_SYMBOL(__inc_zone_page_state);
481
482 void __inc_node_page_state(struct page *page, enum node_stat_item item)
483 {
484 __inc_node_state(page_pgdat(page), item);
485 }
486 EXPORT_SYMBOL(__inc_node_page_state);
487
488 void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
489 {
490 struct per_cpu_zonestat __percpu *pcp = zone->per_cpu_zonestats;
491 s8 __percpu *p = pcp->vm_stat_diff + item;
492 s8 v, t;
493
494 /* See __mod_node_page_state */
495 preempt_disable_nested();
496
497 v = __this_cpu_dec_return(*p);
498 t = __this_cpu_read(pcp->stat_threshold);
499 if (unlikely(v < - t)) {
500 s8 overstep = t >> 1;
501
502 zone_page_state_add(v - overstep, zone, item);
503 __this_cpu_write(*p, overstep);
504 }
505
506 preempt_enable_nested();
507 }
508
509 void __dec_node_state(struct pglist_data *pgdat, enum node_stat_item item)
510 {
511 struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
512 s8 __percpu *p = pcp->vm_node_stat_diff + item;
513 s8 v, t;
514
515 VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
516
517 /* See __mod_node_page_state */
518 preempt_disable_nested();
519
520 v = __this_cpu_dec_return(*p);
521 t = __this_cpu_read(pcp->stat_threshold);
522 if (unlikely(v < - t)) {
523 s8 overstep = t >> 1;
524
525 node_page_state_add(v - overstep, pgdat, item);
526 __this_cpu_write(*p, overstep);
527 }
528
529 preempt_enable_nested();
530 }
531
532 void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
533 {
534 __dec_zone_state(page_zone(page), item);
535 }
536 EXPORT_SYMBOL(__dec_zone_page_state);
537
538 void __dec_node_page_state(struct page *page, enum node_stat_item item)
539 {
540 __dec_node_state(page_pgdat(page), item);
541 }
542 EXPORT_SYMBOL(__dec_node_page_state);
543
544 #ifdef CONFIG_HAVE_CMPXCHG_LOCAL
545 /*
546 * If we have cmpxchg_local support then we do not need to incur the overhead
547 * that comes with local_irq_save/restore if we use this_cpu_cmpxchg.
548 *
549 * mod_state() modifies the zone counter state through atomic per cpu
550 * operations.
551 *
552 * Overstep mode specifies how overstep should handled:
553 * 0 No overstepping
554 * 1 Overstepping half of threshold
555 * -1 Overstepping minus half of threshold
556 */
557 static inline void mod_zone_state(struct zone *zone,
558 enum zone_stat_item item, long delta, int overstep_mode)
559 {
560 struct per_cpu_zonestat __percpu *pcp = zone->per_cpu_zonestats;
561 s8 __percpu *p = pcp->vm_stat_diff + item;
562 long n, t, z;
563 s8 o;
564
565 o = this_cpu_read(*p);
566 do {
567 z = 0; /* overflow to zone counters */
568
569 /*
570 * The fetching of the stat_threshold is racy. We may apply
571 * a counter threshold to the wrong the cpu if we get
572 * rescheduled while executing here. However, the next
573 * counter update will apply the threshold again and
574 * therefore bring the counter under the threshold again.
575 *
576 * Most of the time the thresholds are the same anyways
577 * for all cpus in a zone.
578 */
579 t = this_cpu_read(pcp->stat_threshold);
580
581 n = delta + (long)o;
582
583 if (abs(n) > t) {
584 int os = overstep_mode * (t >> 1) ;
585
586 /* Overflow must be added to zone counters */
587 z = n + os;
588 n = -os;
589 }
590 } while (!this_cpu_try_cmpxchg(*p, &o, n));
591
592 if (z)
593 zone_page_state_add(z, zone, item);
594 }
595
596 void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
597 long delta)
598 {
599 mod_zone_state(zone, item, delta, 0);
600 }
601 EXPORT_SYMBOL(mod_zone_page_state);
602
603 void inc_zone_page_state(struct page *page, enum zone_stat_item item)
604 {
605 mod_zone_state(page_zone(page), item, 1, 1);
606 }
607 EXPORT_SYMBOL(inc_zone_page_state);
608
609 void dec_zone_page_state(struct page *page, enum zone_stat_item item)
610 {
611 mod_zone_state(page_zone(page), item, -1, -1);
612 }
613 EXPORT_SYMBOL(dec_zone_page_state);
614
615 static inline void mod_node_state(struct pglist_data *pgdat,
616 enum node_stat_item item, int delta, int overstep_mode)
617 {
618 struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
619 s8 __percpu *p = pcp->vm_node_stat_diff + item;
620 long n, t, z;
621 s8 o;
622
623 if (vmstat_item_in_bytes(item)) {
624 /*
625 * Only cgroups use subpage accounting right now; at
626 * the global level, these items still change in
627 * multiples of whole pages. Store them as pages
628 * internally to keep the per-cpu counters compact.
629 */
630 VM_WARN_ON_ONCE(delta & (PAGE_SIZE - 1));
631 delta >>= PAGE_SHIFT;
632 }
633
634 o = this_cpu_read(*p);
635 do {
636 z = 0; /* overflow to node counters */
637
638 /*
639 * The fetching of the stat_threshold is racy. We may apply
640 * a counter threshold to the wrong the cpu if we get
641 * rescheduled while executing here. However, the next
642 * counter update will apply the threshold again and
643 * therefore bring the counter under the threshold again.
644 *
645 * Most of the time the thresholds are the same anyways
646 * for all cpus in a node.
647 */
648 t = this_cpu_read(pcp->stat_threshold);
649
650 n = delta + (long)o;
651
652 if (abs(n) > t) {
653 int os = overstep_mode * (t >> 1) ;
654
655 /* Overflow must be added to node counters */
656 z = n + os;
657 n = -os;
658 }
659 } while (!this_cpu_try_cmpxchg(*p, &o, n));
660
661 if (z)
662 node_page_state_add(z, pgdat, item);
663 }
664
665 void mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
666 long delta)
667 {
668 mod_node_state(pgdat, item, delta, 0);
669 }
670 EXPORT_SYMBOL(mod_node_page_state);
671
672 void inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
673 {
674 mod_node_state(pgdat, item, 1, 1);
675 }
676
677 void inc_node_page_state(struct page *page, enum node_stat_item item)
678 {
679 mod_node_state(page_pgdat(page), item, 1, 1);
680 }
681 EXPORT_SYMBOL(inc_node_page_state);
682
683 void dec_node_page_state(struct page *page, enum node_stat_item item)
684 {
685 mod_node_state(page_pgdat(page), item, -1, -1);
686 }
687 EXPORT_SYMBOL(dec_node_page_state);
688 #else
689 /*
690 * Use interrupt disable to serialize counter updates
691 */
692 void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
693 long delta)
694 {
695 unsigned long flags;
696
697 local_irq_save(flags);
698 __mod_zone_page_state(zone, item, delta);
699 local_irq_restore(flags);
700 }
701 EXPORT_SYMBOL(mod_zone_page_state);
702
703 void inc_zone_page_state(struct page *page, enum zone_stat_item item)
704 {
705 unsigned long flags;
706 struct zone *zone;
707
708 zone = page_zone(page);
709 local_irq_save(flags);
710 __inc_zone_state(zone, item);
711 local_irq_restore(flags);
712 }
713 EXPORT_SYMBOL(inc_zone_page_state);
714
715 void dec_zone_page_state(struct page *page, enum zone_stat_item item)
716 {
717 unsigned long flags;
718
719 local_irq_save(flags);
720 __dec_zone_page_state(page, item);
721 local_irq_restore(flags);
722 }
723 EXPORT_SYMBOL(dec_zone_page_state);
724
725 void inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
726 {
727 unsigned long flags;
728
729 local_irq_save(flags);
730 __inc_node_state(pgdat, item);
731 local_irq_restore(flags);
732 }
733 EXPORT_SYMBOL(inc_node_state);
734
735 void mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
736 long delta)
737 {
738 unsigned long flags;
739
740 local_irq_save(flags);
741 __mod_node_page_state(pgdat, item, delta);
742 local_irq_restore(flags);
743 }
744 EXPORT_SYMBOL(mod_node_page_state);
745
746 void inc_node_page_state(struct page *page, enum node_stat_item item)
747 {
748 unsigned long flags;
749 struct pglist_data *pgdat;
750
751 pgdat = page_pgdat(page);
752 local_irq_save(flags);
753 __inc_node_state(pgdat, item);
754 local_irq_restore(flags);
755 }
756 EXPORT_SYMBOL(inc_node_page_state);
757
758 void dec_node_page_state(struct page *page, enum node_stat_item item)
759 {
760 unsigned long flags;
761
762 local_irq_save(flags);
763 __dec_node_page_state(page, item);
764 local_irq_restore(flags);
765 }
766 EXPORT_SYMBOL(dec_node_page_state);
767 #endif
768
769 /*
770 * Fold a differential into the global counters.
771 * Returns the number of counters updated.
772 */
773 static int fold_diff(int *zone_diff, int *node_diff)
774 {
775 int i;
776 int changes = 0;
777
778 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
779 if (zone_diff[i]) {
780 atomic_long_add(zone_diff[i], &vm_zone_stat[i]);
781 changes++;
782 }
783
784 for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
785 if (node_diff[i]) {
786 atomic_long_add(node_diff[i], &vm_node_stat[i]);
787 changes++;
788 }
789 return changes;
790 }
791
792 /*
793 * Update the zone counters for the current cpu.
794 *
795 * Note that refresh_cpu_vm_stats strives to only access
796 * node local memory. The per cpu pagesets on remote zones are placed
797 * in the memory local to the processor using that pageset. So the
798 * loop over all zones will access a series of cachelines local to
799 * the processor.
800 *
801 * The call to zone_page_state_add updates the cachelines with the
802 * statistics in the remote zone struct as well as the global cachelines
803 * with the global counters. These could cause remote node cache line
804 * bouncing and will have to be only done when necessary.
805 *
806 * The function returns the number of global counters updated.
807 */
808 static int refresh_cpu_vm_stats(bool do_pagesets)
809 {
810 struct pglist_data *pgdat;
811 struct zone *zone;
812 int i;
813 int global_zone_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
814 int global_node_diff[NR_VM_NODE_STAT_ITEMS] = { 0, };
815 int changes = 0;
816
817 for_each_populated_zone(zone) {
818 struct per_cpu_zonestat __percpu *pzstats = zone->per_cpu_zonestats;
819 struct per_cpu_pages __percpu *pcp = zone->per_cpu_pageset;
820
821 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
822 int v;
823
824 v = this_cpu_xchg(pzstats->vm_stat_diff[i], 0);
825 if (v) {
826
827 atomic_long_add(v, &zone->vm_stat[i]);
828 global_zone_diff[i] += v;
829 #ifdef CONFIG_NUMA
830 /* 3 seconds idle till flush */
831 __this_cpu_write(pcp->expire, 3);
832 #endif
833 }
834 }
835
836 if (do_pagesets) {
837 cond_resched();
838
839 changes += decay_pcp_high(zone, this_cpu_ptr(pcp));
840 #ifdef CONFIG_NUMA
841 /*
842 * Deal with draining the remote pageset of this
843 * processor
844 *
845 * Check if there are pages remaining in this pageset
846 * if not then there is nothing to expire.
847 */
848 if (!__this_cpu_read(pcp->expire) ||
849 !__this_cpu_read(pcp->count))
850 continue;
851
852 /*
853 * We never drain zones local to this processor.
854 */
855 if (zone_to_nid(zone) == numa_node_id()) {
856 __this_cpu_write(pcp->expire, 0);
857 continue;
858 }
859
860 if (__this_cpu_dec_return(pcp->expire)) {
861 changes++;
862 continue;
863 }
864
865 if (__this_cpu_read(pcp->count)) {
866 drain_zone_pages(zone, this_cpu_ptr(pcp));
867 changes++;
868 }
869 #endif
870 }
871 }
872
873 for_each_online_pgdat(pgdat) {
874 struct per_cpu_nodestat __percpu *p = pgdat->per_cpu_nodestats;
875
876 for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
877 int v;
878
879 v = this_cpu_xchg(p->vm_node_stat_diff[i], 0);
880 if (v) {
881 atomic_long_add(v, &pgdat->vm_stat[i]);
882 global_node_diff[i] += v;
883 }
884 }
885 }
886
887 changes += fold_diff(global_zone_diff, global_node_diff);
888 return changes;
889 }
890
891 /*
892 * Fold the data for an offline cpu into the global array.
893 * There cannot be any access by the offline cpu and therefore
894 * synchronization is simplified.
895 */
896 void cpu_vm_stats_fold(int cpu)
897 {
898 struct pglist_data *pgdat;
899 struct zone *zone;
900 int i;
901 int global_zone_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
902 int global_node_diff[NR_VM_NODE_STAT_ITEMS] = { 0, };
903
904 for_each_populated_zone(zone) {
905 struct per_cpu_zonestat *pzstats;
906
907 pzstats = per_cpu_ptr(zone->per_cpu_zonestats, cpu);
908
909 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
910 if (pzstats->vm_stat_diff[i]) {
911 int v;
912
913 v = pzstats->vm_stat_diff[i];
914 pzstats->vm_stat_diff[i] = 0;
915 atomic_long_add(v, &zone->vm_stat[i]);
916 global_zone_diff[i] += v;
917 }
918 }
919 #ifdef CONFIG_NUMA
920 for (i = 0; i < NR_VM_NUMA_EVENT_ITEMS; i++) {
921 if (pzstats->vm_numa_event[i]) {
922 unsigned long v;
923
924 v = pzstats->vm_numa_event[i];
925 pzstats->vm_numa_event[i] = 0;
926 zone_numa_event_add(v, zone, i);
927 }
928 }
929 #endif
930 }
931
932 for_each_online_pgdat(pgdat) {
933 struct per_cpu_nodestat *p;
934
935 p = per_cpu_ptr(pgdat->per_cpu_nodestats, cpu);
936
937 for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
938 if (p->vm_node_stat_diff[i]) {
939 int v;
940
941 v = p->vm_node_stat_diff[i];
942 p->vm_node_stat_diff[i] = 0;
943 atomic_long_add(v, &pgdat->vm_stat[i]);
944 global_node_diff[i] += v;
945 }
946 }
947
948 fold_diff(global_zone_diff, global_node_diff);
949 }
950
951 /*
952 * this is only called if !populated_zone(zone), which implies no other users of
953 * pset->vm_stat_diff[] exist.
954 */
955 void drain_zonestat(struct zone *zone, struct per_cpu_zonestat *pzstats)
956 {
957 unsigned long v;
958 int i;
959
960 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
961 if (pzstats->vm_stat_diff[i]) {
962 v = pzstats->vm_stat_diff[i];
963 pzstats->vm_stat_diff[i] = 0;
964 zone_page_state_add(v, zone, i);
965 }
966 }
967
968 #ifdef CONFIG_NUMA
969 for (i = 0; i < NR_VM_NUMA_EVENT_ITEMS; i++) {
970 if (pzstats->vm_numa_event[i]) {
971 v = pzstats->vm_numa_event[i];
972 pzstats->vm_numa_event[i] = 0;
973 zone_numa_event_add(v, zone, i);
974 }
975 }
976 #endif
977 }
978 #endif
979
980 #ifdef CONFIG_NUMA
981 /*
982 * Determine the per node value of a stat item. This function
983 * is called frequently in a NUMA machine, so try to be as
984 * frugal as possible.
985 */
986 unsigned long sum_zone_node_page_state(int node,
987 enum zone_stat_item item)
988 {
989 struct zone *zones = NODE_DATA(node)->node_zones;
990 int i;
991 unsigned long count = 0;
992
993 for (i = 0; i < MAX_NR_ZONES; i++)
994 count += zone_page_state(zones + i, item);
995
996 return count;
997 }
998
999 /* Determine the per node value of a numa stat item. */
1000 unsigned long sum_zone_numa_event_state(int node,
1001 enum numa_stat_item item)
1002 {
1003 struct zone *zones = NODE_DATA(node)->node_zones;
1004 unsigned long count = 0;
1005 int i;
1006
1007 for (i = 0; i < MAX_NR_ZONES; i++)
1008 count += zone_numa_event_state(zones + i, item);
1009
1010 return count;
1011 }
1012
1013 /*
1014 * Determine the per node value of a stat item.
1015 */
1016 unsigned long node_page_state_pages(struct pglist_data *pgdat,
1017 enum node_stat_item item)
1018 {
1019 long x = atomic_long_read(&pgdat->vm_stat[item]);
1020 #ifdef CONFIG_SMP
1021 if (x < 0)
1022 x = 0;
1023 #endif
1024 return x;
1025 }
1026
1027 unsigned long node_page_state(struct pglist_data *pgdat,
1028 enum node_stat_item item)
1029 {
1030 VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
1031
1032 return node_page_state_pages(pgdat, item);
1033 }
1034 #endif
1035
1036 #ifdef CONFIG_COMPACTION
1037
1038 struct contig_page_info {
1039 unsigned long free_pages;
1040 unsigned long free_blocks_total;
1041 unsigned long free_blocks_suitable;
1042 };
1043
1044 /*
1045 * Calculate the number of free pages in a zone, how many contiguous
1046 * pages are free and how many are large enough to satisfy an allocation of
1047 * the target size. Note that this function makes no attempt to estimate
1048 * how many suitable free blocks there *might* be if MOVABLE pages were
1049 * migrated. Calculating that is possible, but expensive and can be
1050 * figured out from userspace
1051 */
1052 static void fill_contig_page_info(struct zone *zone,
1053 unsigned int suitable_order,
1054 struct contig_page_info *info)
1055 {
1056 unsigned int order;
1057
1058 info->free_pages = 0;
1059 info->free_blocks_total = 0;
1060 info->free_blocks_suitable = 0;
1061
1062 for (order = 0; order < NR_PAGE_ORDERS; order++) {
1063 unsigned long blocks;
1064
1065 /*
1066 * Count number of free blocks.
1067 *
1068 * Access to nr_free is lockless as nr_free is used only for
1069 * diagnostic purposes. Use data_race to avoid KCSAN warning.
1070 */
1071 blocks = data_race(zone->free_area[order].nr_free);
1072 info->free_blocks_total += blocks;
1073
1074 /* Count free base pages */
1075 info->free_pages += blocks << order;
1076
1077 /* Count the suitable free blocks */
1078 if (order >= suitable_order)
1079 info->free_blocks_suitable += blocks <<
1080 (order - suitable_order);
1081 }
1082 }
1083
1084 /*
1085 * A fragmentation index only makes sense if an allocation of a requested
1086 * size would fail. If that is true, the fragmentation index indicates
1087 * whether external fragmentation or a lack of memory was the problem.
1088 * The value can be used to determine if page reclaim or compaction
1089 * should be used
1090 */
1091 static int __fragmentation_index(unsigned int order, struct contig_page_info *info)
1092 {
1093 unsigned long requested = 1UL << order;
1094
1095 if (WARN_ON_ONCE(order > MAX_PAGE_ORDER))
1096 return 0;
1097
1098 if (!info->free_blocks_total)
1099 return 0;
1100
1101 /* Fragmentation index only makes sense when a request would fail */
1102 if (info->free_blocks_suitable)
1103 return -1000;
1104
1105 /*
1106 * Index is between 0 and 1 so return within 3 decimal places
1107 *
1108 * 0 => allocation would fail due to lack of memory
1109 * 1 => allocation would fail due to fragmentation
1110 */
1111 return 1000 - div_u64( (1000+(div_u64(info->free_pages * 1000ULL, requested))), info->free_blocks_total);
1112 }
1113
1114 /*
1115 * Calculates external fragmentation within a zone wrt the given order.
1116 * It is defined as the percentage of pages found in blocks of size
1117 * less than 1 << order. It returns values in range [0, 100].
1118 */
1119 unsigned int extfrag_for_order(struct zone *zone, unsigned int order)
1120 {
1121 struct contig_page_info info;
1122
1123 fill_contig_page_info(zone, order, &info);
1124 if (info.free_pages == 0)
1125 return 0;
1126
1127 return div_u64((info.free_pages -
1128 (info.free_blocks_suitable << order)) * 100,
1129 info.free_pages);
1130 }
1131
1132 /* Same as __fragmentation index but allocs contig_page_info on stack */
1133 int fragmentation_index(struct zone *zone, unsigned int order)
1134 {
1135 struct contig_page_info info;
1136
1137 fill_contig_page_info(zone, order, &info);
1138 return __fragmentation_index(order, &info);
1139 }
1140 #endif
1141
1142 #if defined(CONFIG_PROC_FS) || defined(CONFIG_SYSFS) || \
1143 defined(CONFIG_NUMA) || defined(CONFIG_MEMCG)
1144 #ifdef CONFIG_ZONE_DMA
1145 #define TEXT_FOR_DMA(xx) xx "_dma",
1146 #else
1147 #define TEXT_FOR_DMA(xx)
1148 #endif
1149
1150 #ifdef CONFIG_ZONE_DMA32
1151 #define TEXT_FOR_DMA32(xx) xx "_dma32",
1152 #else
1153 #define TEXT_FOR_DMA32(xx)
1154 #endif
1155
1156 #ifdef CONFIG_HIGHMEM
1157 #define TEXT_FOR_HIGHMEM(xx) xx "_high",
1158 #else
1159 #define TEXT_FOR_HIGHMEM(xx)
1160 #endif
1161
1162 #ifdef CONFIG_ZONE_DEVICE
1163 #define TEXT_FOR_DEVICE(xx) xx "_device",
1164 #else
1165 #define TEXT_FOR_DEVICE(xx)
1166 #endif
1167
1168 #define TEXTS_FOR_ZONES(xx) TEXT_FOR_DMA(xx) TEXT_FOR_DMA32(xx) xx "_normal", \
1169 TEXT_FOR_HIGHMEM(xx) xx "_movable", \
1170 TEXT_FOR_DEVICE(xx)
1171
1172 const char * const vmstat_text[] = {
1173 /* enum zone_stat_item counters */
1174 "nr_free_pages",
1175 "nr_zone_inactive_anon",
1176 "nr_zone_active_anon",
1177 "nr_zone_inactive_file",
1178 "nr_zone_active_file",
1179 "nr_zone_unevictable",
1180 "nr_zone_write_pending",
1181 "nr_mlock",
1182 "nr_bounce",
1183 #if IS_ENABLED(CONFIG_ZSMALLOC)
1184 "nr_zspages",
1185 #endif
1186 "nr_free_cma",
1187 #ifdef CONFIG_UNACCEPTED_MEMORY
1188 "nr_unaccepted",
1189 #endif
1190
1191 /* enum numa_stat_item counters */
1192 #ifdef CONFIG_NUMA
1193 "numa_hit",
1194 "numa_miss",
1195 "numa_foreign",
1196 "numa_interleave",
1197 "numa_local",
1198 "numa_other",
1199 #endif
1200
1201 /* enum node_stat_item counters */
1202 "nr_inactive_anon",
1203 "nr_active_anon",
1204 "nr_inactive_file",
1205 "nr_active_file",
1206 "nr_unevictable",
1207 "nr_slab_reclaimable",
1208 "nr_slab_unreclaimable",
1209 "nr_isolated_anon",
1210 "nr_isolated_file",
1211 "workingset_nodes",
1212 "workingset_refault_anon",
1213 "workingset_refault_file",
1214 "workingset_activate_anon",
1215 "workingset_activate_file",
1216 "workingset_restore_anon",
1217 "workingset_restore_file",
1218 "workingset_nodereclaim",
1219 "nr_anon_pages",
1220 "nr_mapped",
1221 "nr_file_pages",
1222 "nr_dirty",
1223 "nr_writeback",
1224 "nr_writeback_temp",
1225 "nr_shmem",
1226 "nr_shmem_hugepages",
1227 "nr_shmem_pmdmapped",
1228 "nr_file_hugepages",
1229 "nr_file_pmdmapped",
1230 "nr_anon_transparent_hugepages",
1231 "nr_vmscan_write",
1232 "nr_vmscan_immediate_reclaim",
1233 "nr_dirtied",
1234 "nr_written",
1235 "nr_throttled_written",
1236 "nr_kernel_misc_reclaimable",
1237 "nr_foll_pin_acquired",
1238 "nr_foll_pin_released",
1239 "nr_kernel_stack",
1240 #if IS_ENABLED(CONFIG_SHADOW_CALL_STACK)
1241 "nr_shadow_call_stack",
1242 #endif
1243 "nr_page_table_pages",
1244 "nr_sec_page_table_pages",
1245 #ifdef CONFIG_IOMMU_SUPPORT
1246 "nr_iommu_pages",
1247 #endif
1248 #ifdef CONFIG_SWAP
1249 "nr_swapcached",
1250 #endif
1251 #ifdef CONFIG_NUMA_BALANCING
1252 "pgpromote_success",
1253 "pgpromote_candidate",
1254 #endif
1255 "pgdemote_kswapd",
1256 "pgdemote_direct",
1257 "pgdemote_khugepaged",
1258 "nr_memmap",
1259 "nr_memmap_boot",
1260 /* enum writeback_stat_item counters */
1261 "nr_dirty_threshold",
1262 "nr_dirty_background_threshold",
1263
1264 #if defined(CONFIG_VM_EVENT_COUNTERS) || defined(CONFIG_MEMCG)
1265 /* enum vm_event_item counters */
1266 "pgpgin",
1267 "pgpgout",
1268 "pswpin",
1269 "pswpout",
1270
1271 TEXTS_FOR_ZONES("pgalloc")
1272 TEXTS_FOR_ZONES("allocstall")
1273 TEXTS_FOR_ZONES("pgskip")
1274
1275 "pgfree",
1276 "pgactivate",
1277 "pgdeactivate",
1278 "pglazyfree",
1279
1280 "pgfault",
1281 "pgmajfault",
1282 "pglazyfreed",
1283
1284 "pgrefill",
1285 "pgreuse",
1286 "pgsteal_kswapd",
1287 "pgsteal_direct",
1288 "pgsteal_khugepaged",
1289 "pgscan_kswapd",
1290 "pgscan_direct",
1291 "pgscan_khugepaged",
1292 "pgscan_direct_throttle",
1293 "pgscan_anon",
1294 "pgscan_file",
1295 "pgsteal_anon",
1296 "pgsteal_file",
1297
1298 #ifdef CONFIG_NUMA
1299 "zone_reclaim_failed",
1300 #endif
1301 "pginodesteal",
1302 "slabs_scanned",
1303 "kswapd_inodesteal",
1304 "kswapd_low_wmark_hit_quickly",
1305 "kswapd_high_wmark_hit_quickly",
1306 "pageoutrun",
1307
1308 "pgrotated",
1309
1310 "drop_pagecache",
1311 "drop_slab",
1312 "oom_kill",
1313
1314 #ifdef CONFIG_NUMA_BALANCING
1315 "numa_pte_updates",
1316 "numa_huge_pte_updates",
1317 "numa_hint_faults",
1318 "numa_hint_faults_local",
1319 "numa_pages_migrated",
1320 #endif
1321 #ifdef CONFIG_MIGRATION
1322 "pgmigrate_success",
1323 "pgmigrate_fail",
1324 "thp_migration_success",
1325 "thp_migration_fail",
1326 "thp_migration_split",
1327 #endif
1328 #ifdef CONFIG_COMPACTION
1329 "compact_migrate_scanned",
1330 "compact_free_scanned",
1331 "compact_isolated",
1332 "compact_stall",
1333 "compact_fail",
1334 "compact_success",
1335 "compact_daemon_wake",
1336 "compact_daemon_migrate_scanned",
1337 "compact_daemon_free_scanned",
1338 #endif
1339
1340 #ifdef CONFIG_HUGETLB_PAGE
1341 "htlb_buddy_alloc_success",
1342 "htlb_buddy_alloc_fail",
1343 #endif
1344 #ifdef CONFIG_CMA
1345 "cma_alloc_success",
1346 "cma_alloc_fail",
1347 #endif
1348 "unevictable_pgs_culled",
1349 "unevictable_pgs_scanned",
1350 "unevictable_pgs_rescued",
1351 "unevictable_pgs_mlocked",
1352 "unevictable_pgs_munlocked",
1353 "unevictable_pgs_cleared",
1354 "unevictable_pgs_stranded",
1355
1356 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1357 "thp_fault_alloc",
1358 "thp_fault_fallback",
1359 "thp_fault_fallback_charge",
1360 "thp_collapse_alloc",
1361 "thp_collapse_alloc_failed",
1362 "thp_file_alloc",
1363 "thp_file_fallback",
1364 "thp_file_fallback_charge",
1365 "thp_file_mapped",
1366 "thp_split_page",
1367 "thp_split_page_failed",
1368 "thp_deferred_split_page",
1369 "thp_split_pmd",
1370 "thp_scan_exceed_none_pte",
1371 "thp_scan_exceed_swap_pte",
1372 "thp_scan_exceed_share_pte",
1373 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
1374 "thp_split_pud",
1375 #endif
1376 "thp_zero_page_alloc",
1377 "thp_zero_page_alloc_failed",
1378 "thp_swpout",
1379 "thp_swpout_fallback",
1380 #endif
1381 #ifdef CONFIG_MEMORY_BALLOON
1382 "balloon_inflate",
1383 "balloon_deflate",
1384 #ifdef CONFIG_BALLOON_COMPACTION
1385 "balloon_migrate",
1386 #endif
1387 #endif /* CONFIG_MEMORY_BALLOON */
1388 #ifdef CONFIG_DEBUG_TLBFLUSH
1389 "nr_tlb_remote_flush",
1390 "nr_tlb_remote_flush_received",
1391 "nr_tlb_local_flush_all",
1392 "nr_tlb_local_flush_one",
1393 #endif /* CONFIG_DEBUG_TLBFLUSH */
1394
1395 #ifdef CONFIG_SWAP
1396 "swap_ra",
1397 "swap_ra_hit",
1398 #ifdef CONFIG_KSM
1399 "ksm_swpin_copy",
1400 #endif
1401 #endif
1402 #ifdef CONFIG_KSM
1403 "cow_ksm",
1404 #endif
1405 #ifdef CONFIG_ZSWAP
1406 "zswpin",
1407 "zswpout",
1408 "zswpwb",
1409 #endif
1410 #ifdef CONFIG_X86
1411 "direct_map_level2_splits",
1412 "direct_map_level3_splits",
1413 #endif
1414 #ifdef CONFIG_PER_VMA_LOCK_STATS
1415 "vma_lock_success",
1416 "vma_lock_abort",
1417 "vma_lock_retry",
1418 "vma_lock_miss",
1419 #endif
1420 #endif /* CONFIG_VM_EVENT_COUNTERS || CONFIG_MEMCG */
1421 };
1422 #endif /* CONFIG_PROC_FS || CONFIG_SYSFS || CONFIG_NUMA || CONFIG_MEMCG */
1423
1424 #if (defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)) || \
1425 defined(CONFIG_PROC_FS)
1426 static void *frag_start(struct seq_file *m, loff_t *pos)
1427 {
1428 pg_data_t *pgdat;
1429 loff_t node = *pos;
1430
1431 for (pgdat = first_online_pgdat();
1432 pgdat && node;
1433 pgdat = next_online_pgdat(pgdat))
1434 --node;
1435
1436 return pgdat;
1437 }
1438
1439 static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
1440 {
1441 pg_data_t *pgdat = (pg_data_t *)arg;
1442
1443 (*pos)++;
1444 return next_online_pgdat(pgdat);
1445 }
1446
1447 static void frag_stop(struct seq_file *m, void *arg)
1448 {
1449 }
1450
1451 /*
1452 * Walk zones in a node and print using a callback.
1453 * If @assert_populated is true, only use callback for zones that are populated.
1454 */
1455 static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat,
1456 bool assert_populated, bool nolock,
1457 void (*print)(struct seq_file *m, pg_data_t *, struct zone *))
1458 {
1459 struct zone *zone;
1460 struct zone *node_zones = pgdat->node_zones;
1461 unsigned long flags;
1462
1463 for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
1464 if (assert_populated && !populated_zone(zone))
1465 continue;
1466
1467 if (!nolock)
1468 spin_lock_irqsave(&zone->lock, flags);
1469 print(m, pgdat, zone);
1470 if (!nolock)
1471 spin_unlock_irqrestore(&zone->lock, flags);
1472 }
1473 }
1474 #endif
1475
1476 #ifdef CONFIG_PROC_FS
1477 static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,
1478 struct zone *zone)
1479 {
1480 int order;
1481
1482 seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
1483 for (order = 0; order < NR_PAGE_ORDERS; ++order)
1484 /*
1485 * Access to nr_free is lockless as nr_free is used only for
1486 * printing purposes. Use data_race to avoid KCSAN warning.
1487 */
1488 seq_printf(m, "%6lu ", data_race(zone->free_area[order].nr_free));
1489 seq_putc(m, '\n');
1490 }
1491
1492 /*
1493 * This walks the free areas for each zone.
1494 */
1495 static int frag_show(struct seq_file *m, void *arg)
1496 {
1497 pg_data_t *pgdat = (pg_data_t *)arg;
1498 walk_zones_in_node(m, pgdat, true, false, frag_show_print);
1499 return 0;
1500 }
1501
1502 static void pagetypeinfo_showfree_print(struct seq_file *m,
1503 pg_data_t *pgdat, struct zone *zone)
1504 {
1505 int order, mtype;
1506
1507 for (mtype = 0; mtype < MIGRATE_TYPES; mtype++) {
1508 seq_printf(m, "Node %4d, zone %8s, type %12s ",
1509 pgdat->node_id,
1510 zone->name,
1511 migratetype_names[mtype]);
1512 for (order = 0; order < NR_PAGE_ORDERS; ++order) {
1513 unsigned long freecount = 0;
1514 struct free_area *area;
1515 struct list_head *curr;
1516 bool overflow = false;
1517
1518 area = &(zone->free_area[order]);
1519
1520 list_for_each(curr, &area->free_list[mtype]) {
1521 /*
1522 * Cap the free_list iteration because it might
1523 * be really large and we are under a spinlock
1524 * so a long time spent here could trigger a
1525 * hard lockup detector. Anyway this is a
1526 * debugging tool so knowing there is a handful
1527 * of pages of this order should be more than
1528 * sufficient.
1529 */
1530 if (++freecount >= 100000) {
1531 overflow = true;
1532 break;
1533 }
1534 }
1535 seq_printf(m, "%s%6lu ", overflow ? ">" : "", freecount);
1536 spin_unlock_irq(&zone->lock);
1537 cond_resched();
1538 spin_lock_irq(&zone->lock);
1539 }
1540 seq_putc(m, '\n');
1541 }
1542 }
1543
1544 /* Print out the free pages at each order for each migatetype */
1545 static void pagetypeinfo_showfree(struct seq_file *m, void *arg)
1546 {
1547 int order;
1548 pg_data_t *pgdat = (pg_data_t *)arg;
1549
1550 /* Print header */
1551 seq_printf(m, "%-43s ", "Free pages count per migrate type at order");
1552 for (order = 0; order < NR_PAGE_ORDERS; ++order)
1553 seq_printf(m, "%6d ", order);
1554 seq_putc(m, '\n');
1555
1556 walk_zones_in_node(m, pgdat, true, false, pagetypeinfo_showfree_print);
1557 }
1558
1559 static void pagetypeinfo_showblockcount_print(struct seq_file *m,
1560 pg_data_t *pgdat, struct zone *zone)
1561 {
1562 int mtype;
1563 unsigned long pfn;
1564 unsigned long start_pfn = zone->zone_start_pfn;
1565 unsigned long end_pfn = zone_end_pfn(zone);
1566 unsigned long count[MIGRATE_TYPES] = { 0, };
1567
1568 for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
1569 struct page *page;
1570
1571 page = pfn_to_online_page(pfn);
1572 if (!page)
1573 continue;
1574
1575 if (page_zone(page) != zone)
1576 continue;
1577
1578 mtype = get_pageblock_migratetype(page);
1579
1580 if (mtype < MIGRATE_TYPES)
1581 count[mtype]++;
1582 }
1583
1584 /* Print counts */
1585 seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
1586 for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
1587 seq_printf(m, "%12lu ", count[mtype]);
1588 seq_putc(m, '\n');
1589 }
1590
1591 /* Print out the number of pageblocks for each migratetype */
1592 static void pagetypeinfo_showblockcount(struct seq_file *m, void *arg)
1593 {
1594 int mtype;
1595 pg_data_t *pgdat = (pg_data_t *)arg;
1596
1597 seq_printf(m, "\n%-23s", "Number of blocks type ");
1598 for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
1599 seq_printf(m, "%12s ", migratetype_names[mtype]);
1600 seq_putc(m, '\n');
1601 walk_zones_in_node(m, pgdat, true, false,
1602 pagetypeinfo_showblockcount_print);
1603 }
1604
1605 /*
1606 * Print out the number of pageblocks for each migratetype that contain pages
1607 * of other types. This gives an indication of how well fallbacks are being
1608 * contained by rmqueue_fallback(). It requires information from PAGE_OWNER
1609 * to determine what is going on
1610 */
1611 static void pagetypeinfo_showmixedcount(struct seq_file *m, pg_data_t *pgdat)
1612 {
1613 #ifdef CONFIG_PAGE_OWNER
1614 int mtype;
1615
1616 if (!static_branch_unlikely(&page_owner_inited))
1617 return;
1618
1619 drain_all_pages(NULL);
1620
1621 seq_printf(m, "\n%-23s", "Number of mixed blocks ");
1622 for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
1623 seq_printf(m, "%12s ", migratetype_names[mtype]);
1624 seq_putc(m, '\n');
1625
1626 walk_zones_in_node(m, pgdat, true, true,
1627 pagetypeinfo_showmixedcount_print);
1628 #endif /* CONFIG_PAGE_OWNER */
1629 }
1630
1631 /*
1632 * This prints out statistics in relation to grouping pages by mobility.
1633 * It is expensive to collect so do not constantly read the file.
1634 */
1635 static int pagetypeinfo_show(struct seq_file *m, void *arg)
1636 {
1637 pg_data_t *pgdat = (pg_data_t *)arg;
1638
1639 /* check memoryless node */
1640 if (!node_state(pgdat->node_id, N_MEMORY))
1641 return 0;
1642
1643 seq_printf(m, "Page block order: %d\n", pageblock_order);
1644 seq_printf(m, "Pages per block: %lu\n", pageblock_nr_pages);
1645 seq_putc(m, '\n');
1646 pagetypeinfo_showfree(m, pgdat);
1647 pagetypeinfo_showblockcount(m, pgdat);
1648 pagetypeinfo_showmixedcount(m, pgdat);
1649
1650 return 0;
1651 }
1652
1653 static const struct seq_operations fragmentation_op = {
1654 .start = frag_start,
1655 .next = frag_next,
1656 .stop = frag_stop,
1657 .show = frag_show,
1658 };
1659
1660 static const struct seq_operations pagetypeinfo_op = {
1661 .start = frag_start,
1662 .next = frag_next,
1663 .stop = frag_stop,
1664 .show = pagetypeinfo_show,
1665 };
1666
1667 static bool is_zone_first_populated(pg_data_t *pgdat, struct zone *zone)
1668 {
1669 int zid;
1670
1671 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
1672 struct zone *compare = &pgdat->node_zones[zid];
1673
1674 if (populated_zone(compare))
1675 return zone == compare;
1676 }
1677
1678 return false;
1679 }
1680
1681 static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
1682 struct zone *zone)
1683 {
1684 int i;
1685 seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name);
1686 if (is_zone_first_populated(pgdat, zone)) {
1687 seq_printf(m, "\n per-node stats");
1688 for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
1689 unsigned long pages = node_page_state_pages(pgdat, i);
1690
1691 if (vmstat_item_print_in_thp(i))
1692 pages /= HPAGE_PMD_NR;
1693 seq_printf(m, "\n %-12s %lu", node_stat_name(i),
1694 pages);
1695 }
1696 }
1697 seq_printf(m,
1698 "\n pages free %lu"
1699 "\n boost %lu"
1700 "\n min %lu"
1701 "\n low %lu"
1702 "\n high %lu"
1703 "\n spanned %lu"
1704 "\n present %lu"
1705 "\n managed %lu"
1706 "\n cma %lu",
1707 zone_page_state(zone, NR_FREE_PAGES),
1708 zone->watermark_boost,
1709 min_wmark_pages(zone),
1710 low_wmark_pages(zone),
1711 high_wmark_pages(zone),
1712 zone->spanned_pages,
1713 zone->present_pages,
1714 zone_managed_pages(zone),
1715 zone_cma_pages(zone));
1716
1717 seq_printf(m,
1718 "\n protection: (%ld",
1719 zone->lowmem_reserve[0]);
1720 for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++)
1721 seq_printf(m, ", %ld", zone->lowmem_reserve[i]);
1722 seq_putc(m, ')');
1723
1724 /* If unpopulated, no other information is useful */
1725 if (!populated_zone(zone)) {
1726 seq_putc(m, '\n');
1727 return;
1728 }
1729
1730 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
1731 seq_printf(m, "\n %-12s %lu", zone_stat_name(i),
1732 zone_page_state(zone, i));
1733
1734 #ifdef CONFIG_NUMA
1735 for (i = 0; i < NR_VM_NUMA_EVENT_ITEMS; i++)
1736 seq_printf(m, "\n %-12s %lu", numa_stat_name(i),
1737 zone_numa_event_state(zone, i));
1738 #endif
1739
1740 seq_printf(m, "\n pagesets");
1741 for_each_online_cpu(i) {
1742 struct per_cpu_pages *pcp;
1743 struct per_cpu_zonestat __maybe_unused *pzstats;
1744
1745 pcp = per_cpu_ptr(zone->per_cpu_pageset, i);
1746 seq_printf(m,
1747 "\n cpu: %i"
1748 "\n count: %i"
1749 "\n high: %i"
1750 "\n batch: %i",
1751 i,
1752 pcp->count,
1753 pcp->high,
1754 pcp->batch);
1755 #ifdef CONFIG_SMP
1756 pzstats = per_cpu_ptr(zone->per_cpu_zonestats, i);
1757 seq_printf(m, "\n vm stats threshold: %d",
1758 pzstats->stat_threshold);
1759 #endif
1760 }
1761 seq_printf(m,
1762 "\n node_unreclaimable: %u"
1763 "\n start_pfn: %lu",
1764 pgdat->kswapd_failures >= MAX_RECLAIM_RETRIES,
1765 zone->zone_start_pfn);
1766 seq_putc(m, '\n');
1767 }
1768
1769 /*
1770 * Output information about zones in @pgdat. All zones are printed regardless
1771 * of whether they are populated or not: lowmem_reserve_ratio operates on the
1772 * set of all zones and userspace would not be aware of such zones if they are
1773 * suppressed here (zoneinfo displays the effect of lowmem_reserve_ratio).
1774 */
1775 static int zoneinfo_show(struct seq_file *m, void *arg)
1776 {
1777 pg_data_t *pgdat = (pg_data_t *)arg;
1778 walk_zones_in_node(m, pgdat, false, false, zoneinfo_show_print);
1779 return 0;
1780 }
1781
1782 static const struct seq_operations zoneinfo_op = {
1783 .start = frag_start, /* iterate over all zones. The same as in
1784 * fragmentation. */
1785 .next = frag_next,
1786 .stop = frag_stop,
1787 .show = zoneinfo_show,
1788 };
1789
1790 #define NR_VMSTAT_ITEMS (NR_VM_ZONE_STAT_ITEMS + \
1791 NR_VM_NUMA_EVENT_ITEMS + \
1792 NR_VM_NODE_STAT_ITEMS + \
1793 NR_VM_WRITEBACK_STAT_ITEMS + \
1794 (IS_ENABLED(CONFIG_VM_EVENT_COUNTERS) ? \
1795 NR_VM_EVENT_ITEMS : 0))
1796
1797 static void *vmstat_start(struct seq_file *m, loff_t *pos)
1798 {
1799 unsigned long *v;
1800 int i;
1801
1802 if (*pos >= NR_VMSTAT_ITEMS)
1803 return NULL;
1804
1805 BUILD_BUG_ON(ARRAY_SIZE(vmstat_text) < NR_VMSTAT_ITEMS);
1806 fold_vm_numa_events();
1807 v = kmalloc_array(NR_VMSTAT_ITEMS, sizeof(unsigned long), GFP_KERNEL);
1808 m->private = v;
1809 if (!v)
1810 return ERR_PTR(-ENOMEM);
1811 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
1812 v[i] = global_zone_page_state(i);
1813 v += NR_VM_ZONE_STAT_ITEMS;
1814
1815 #ifdef CONFIG_NUMA
1816 for (i = 0; i < NR_VM_NUMA_EVENT_ITEMS; i++)
1817 v[i] = global_numa_event_state(i);
1818 v += NR_VM_NUMA_EVENT_ITEMS;
1819 #endif
1820
1821 for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
1822 v[i] = global_node_page_state_pages(i);
1823 if (vmstat_item_print_in_thp(i))
1824 v[i] /= HPAGE_PMD_NR;
1825 }
1826 v += NR_VM_NODE_STAT_ITEMS;
1827
1828 global_dirty_limits(v + NR_DIRTY_BG_THRESHOLD,
1829 v + NR_DIRTY_THRESHOLD);
1830 v += NR_VM_WRITEBACK_STAT_ITEMS;
1831
1832 #ifdef CONFIG_VM_EVENT_COUNTERS
1833 all_vm_events(v);
1834 v[PGPGIN] /= 2; /* sectors -> kbytes */
1835 v[PGPGOUT] /= 2;
1836 #endif
1837 return (unsigned long *)m->private + *pos;
1838 }
1839
1840 static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)
1841 {
1842 (*pos)++;
1843 if (*pos >= NR_VMSTAT_ITEMS)
1844 return NULL;
1845 return (unsigned long *)m->private + *pos;
1846 }
1847
1848 static int vmstat_show(struct seq_file *m, void *arg)
1849 {
1850 unsigned long *l = arg;
1851 unsigned long off = l - (unsigned long *)m->private;
1852
1853 seq_puts(m, vmstat_text[off]);
1854 seq_put_decimal_ull(m, " ", *l);
1855 seq_putc(m, '\n');
1856
1857 if (off == NR_VMSTAT_ITEMS - 1) {
1858 /*
1859 * We've come to the end - add any deprecated counters to avoid
1860 * breaking userspace which might depend on them being present.
1861 */
1862 seq_puts(m, "nr_unstable 0\n");
1863 }
1864 return 0;
1865 }
1866
1867 static void vmstat_stop(struct seq_file *m, void *arg)
1868 {
1869 kfree(m->private);
1870 m->private = NULL;
1871 }
1872
1873 static const struct seq_operations vmstat_op = {
1874 .start = vmstat_start,
1875 .next = vmstat_next,
1876 .stop = vmstat_stop,
1877 .show = vmstat_show,
1878 };
1879 #endif /* CONFIG_PROC_FS */
1880
1881 #ifdef CONFIG_SMP
1882 static DEFINE_PER_CPU(struct delayed_work, vmstat_work);
1883 int sysctl_stat_interval __read_mostly = HZ;
1884
1885 #ifdef CONFIG_PROC_FS
1886 static void refresh_vm_stats(struct work_struct *work)
1887 {
1888 refresh_cpu_vm_stats(true);
1889 }
1890
1891 int vmstat_refresh(const struct ctl_table *table, int write,
1892 void *buffer, size_t *lenp, loff_t *ppos)
1893 {
1894 long val;
1895 int err;
1896 int i;
1897
1898 /*
1899 * The regular update, every sysctl_stat_interval, may come later
1900 * than expected: leaving a significant amount in per_cpu buckets.
1901 * This is particularly misleading when checking a quantity of HUGE
1902 * pages, immediately after running a test. /proc/sys/vm/stat_refresh,
1903 * which can equally be echo'ed to or cat'ted from (by root),
1904 * can be used to update the stats just before reading them.
1905 *
1906 * Oh, and since global_zone_page_state() etc. are so careful to hide
1907 * transiently negative values, report an error here if any of
1908 * the stats is negative, so we know to go looking for imbalance.
1909 */
1910 err = schedule_on_each_cpu(refresh_vm_stats);
1911 if (err)
1912 return err;
1913 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
1914 /*
1915 * Skip checking stats known to go negative occasionally.
1916 */
1917 switch (i) {
1918 case NR_ZONE_WRITE_PENDING:
1919 case NR_FREE_CMA_PAGES:
1920 continue;
1921 }
1922 val = atomic_long_read(&vm_zone_stat[i]);
1923 if (val < 0) {
1924 pr_warn("%s: %s %ld\n",
1925 __func__, zone_stat_name(i), val);
1926 }
1927 }
1928 for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
1929 /*
1930 * Skip checking stats known to go negative occasionally.
1931 */
1932 switch (i) {
1933 case NR_WRITEBACK:
1934 continue;
1935 }
1936 val = atomic_long_read(&vm_node_stat[i]);
1937 if (val < 0) {
1938 pr_warn("%s: %s %ld\n",
1939 __func__, node_stat_name(i), val);
1940 }
1941 }
1942 if (write)
1943 *ppos += *lenp;
1944 else
1945 *lenp = 0;
1946 return 0;
1947 }
1948 #endif /* CONFIG_PROC_FS */
1949
1950 static void vmstat_update(struct work_struct *w)
1951 {
1952 if (refresh_cpu_vm_stats(true)) {
1953 /*
1954 * Counters were updated so we expect more updates
1955 * to occur in the future. Keep on running the
1956 * update worker thread.
1957 */
1958 queue_delayed_work_on(smp_processor_id(), mm_percpu_wq,
1959 this_cpu_ptr(&vmstat_work),
1960 round_jiffies_relative(sysctl_stat_interval));
1961 }
1962 }
1963
1964 /*
1965 * Check if the diffs for a certain cpu indicate that
1966 * an update is needed.
1967 */
1968 static bool need_update(int cpu)
1969 {
1970 pg_data_t *last_pgdat = NULL;
1971 struct zone *zone;
1972
1973 for_each_populated_zone(zone) {
1974 struct per_cpu_zonestat *pzstats = per_cpu_ptr(zone->per_cpu_zonestats, cpu);
1975 struct per_cpu_nodestat *n;
1976
1977 /*
1978 * The fast way of checking if there are any vmstat diffs.
1979 */
1980 if (memchr_inv(pzstats->vm_stat_diff, 0, sizeof(pzstats->vm_stat_diff)))
1981 return true;
1982
1983 if (last_pgdat == zone->zone_pgdat)
1984 continue;
1985 last_pgdat = zone->zone_pgdat;
1986 n = per_cpu_ptr(zone->zone_pgdat->per_cpu_nodestats, cpu);
1987 if (memchr_inv(n->vm_node_stat_diff, 0, sizeof(n->vm_node_stat_diff)))
1988 return true;
1989 }
1990 return false;
1991 }
1992
1993 /*
1994 * Switch off vmstat processing and then fold all the remaining differentials
1995 * until the diffs stay at zero. The function is used by NOHZ and can only be
1996 * invoked when tick processing is not active.
1997 */
1998 void quiet_vmstat(void)
1999 {
2000 if (system_state != SYSTEM_RUNNING)
2001 return;
2002
2003 if (!delayed_work_pending(this_cpu_ptr(&vmstat_work)))
2004 return;
2005
2006 if (!need_update(smp_processor_id()))
2007 return;
2008
2009 /*
2010 * Just refresh counters and do not care about the pending delayed
2011 * vmstat_update. It doesn't fire that often to matter and canceling
2012 * it would be too expensive from this path.
2013 * vmstat_shepherd will take care about that for us.
2014 */
2015 refresh_cpu_vm_stats(false);
2016 }
2017
2018 /*
2019 * Shepherd worker thread that checks the
2020 * differentials of processors that have their worker
2021 * threads for vm statistics updates disabled because of
2022 * inactivity.
2023 */
2024 static void vmstat_shepherd(struct work_struct *w);
2025
2026 static DECLARE_DEFERRABLE_WORK(shepherd, vmstat_shepherd);
2027
2028 static void vmstat_shepherd(struct work_struct *w)
2029 {
2030 int cpu;
2031
2032 cpus_read_lock();
2033 /* Check processors whose vmstat worker threads have been disabled */
2034 for_each_online_cpu(cpu) {
2035 struct delayed_work *dw = &per_cpu(vmstat_work, cpu);
2036
2037 /*
2038 * In kernel users of vmstat counters either require the precise value and
2039 * they are using zone_page_state_snapshot interface or they can live with
2040 * an imprecision as the regular flushing can happen at arbitrary time and
2041 * cumulative error can grow (see calculate_normal_threshold).
2042 *
2043 * From that POV the regular flushing can be postponed for CPUs that have
2044 * been isolated from the kernel interference without critical
2045 * infrastructure ever noticing. Skip regular flushing from vmstat_shepherd
2046 * for all isolated CPUs to avoid interference with the isolated workload.
2047 */
2048 if (cpu_is_isolated(cpu))
2049 continue;
2050
2051 if (!delayed_work_pending(dw) && need_update(cpu))
2052 queue_delayed_work_on(cpu, mm_percpu_wq, dw, 0);
2053
2054 cond_resched();
2055 }
2056 cpus_read_unlock();
2057
2058 schedule_delayed_work(&shepherd,
2059 round_jiffies_relative(sysctl_stat_interval));
2060 }
2061
2062 static void __init start_shepherd_timer(void)
2063 {
2064 int cpu;
2065
2066 for_each_possible_cpu(cpu)
2067 INIT_DEFERRABLE_WORK(per_cpu_ptr(&vmstat_work, cpu),
2068 vmstat_update);
2069
2070 schedule_delayed_work(&shepherd,
2071 round_jiffies_relative(sysctl_stat_interval));
2072 }
2073
2074 static void __init init_cpu_node_state(void)
2075 {
2076 int node;
2077
2078 for_each_online_node(node) {
2079 if (!cpumask_empty(cpumask_of_node(node)))
2080 node_set_state(node, N_CPU);
2081 }
2082 }
2083
2084 static int vmstat_cpu_online(unsigned int cpu)
2085 {
2086 refresh_zone_stat_thresholds();
2087
2088 if (!node_state(cpu_to_node(cpu), N_CPU)) {
2089 node_set_state(cpu_to_node(cpu), N_CPU);
2090 }
2091
2092 return 0;
2093 }
2094
2095 static int vmstat_cpu_down_prep(unsigned int cpu)
2096 {
2097 cancel_delayed_work_sync(&per_cpu(vmstat_work, cpu));
2098 return 0;
2099 }
2100
2101 static int vmstat_cpu_dead(unsigned int cpu)
2102 {
2103 const struct cpumask *node_cpus;
2104 int node;
2105
2106 node = cpu_to_node(cpu);
2107
2108 refresh_zone_stat_thresholds();
2109 node_cpus = cpumask_of_node(node);
2110 if (!cpumask_empty(node_cpus))
2111 return 0;
2112
2113 node_clear_state(node, N_CPU);
2114
2115 return 0;
2116 }
2117
2118 #endif
2119
2120 struct workqueue_struct *mm_percpu_wq;
2121
2122 void __init init_mm_internals(void)
2123 {
2124 int ret __maybe_unused;
2125
2126 mm_percpu_wq = alloc_workqueue("mm_percpu_wq", WQ_MEM_RECLAIM, 0);
2127
2128 #ifdef CONFIG_SMP
2129 ret = cpuhp_setup_state_nocalls(CPUHP_MM_VMSTAT_DEAD, "mm/vmstat:dead",
2130 NULL, vmstat_cpu_dead);
2131 if (ret < 0)
2132 pr_err("vmstat: failed to register 'dead' hotplug state\n");
2133
2134 ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "mm/vmstat:online",
2135 vmstat_cpu_online,
2136 vmstat_cpu_down_prep);
2137 if (ret < 0)
2138 pr_err("vmstat: failed to register 'online' hotplug state\n");
2139
2140 cpus_read_lock();
2141 init_cpu_node_state();
2142 cpus_read_unlock();
2143
2144 start_shepherd_timer();
2145 #endif
2146 #ifdef CONFIG_PROC_FS
2147 proc_create_seq("buddyinfo", 0444, NULL, &fragmentation_op);
2148 proc_create_seq("pagetypeinfo", 0400, NULL, &pagetypeinfo_op);
2149 proc_create_seq("vmstat", 0444, NULL, &vmstat_op);
2150 proc_create_seq("zoneinfo", 0444, NULL, &zoneinfo_op);
2151 #endif
2152 }
2153
2154 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)
2155
2156 /*
2157 * Return an index indicating how much of the available free memory is
2158 * unusable for an allocation of the requested size.
2159 */
2160 static int unusable_free_index(unsigned int order,
2161 struct contig_page_info *info)
2162 {
2163 /* No free memory is interpreted as all free memory is unusable */
2164 if (info->free_pages == 0)
2165 return 1000;
2166
2167 /*
2168 * Index should be a value between 0 and 1. Return a value to 3
2169 * decimal places.
2170 *
2171 * 0 => no fragmentation
2172 * 1 => high fragmentation
2173 */
2174 return div_u64((info->free_pages - (info->free_blocks_suitable << order)) * 1000ULL, info->free_pages);
2175
2176 }
2177
2178 static void unusable_show_print(struct seq_file *m,
2179 pg_data_t *pgdat, struct zone *zone)
2180 {
2181 unsigned int order;
2182 int index;
2183 struct contig_page_info info;
2184
2185 seq_printf(m, "Node %d, zone %8s ",
2186 pgdat->node_id,
2187 zone->name);
2188 for (order = 0; order < NR_PAGE_ORDERS; ++order) {
2189 fill_contig_page_info(zone, order, &info);
2190 index = unusable_free_index(order, &info);
2191 seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
2192 }
2193
2194 seq_putc(m, '\n');
2195 }
2196
2197 /*
2198 * Display unusable free space index
2199 *
2200 * The unusable free space index measures how much of the available free
2201 * memory cannot be used to satisfy an allocation of a given size and is a
2202 * value between 0 and 1. The higher the value, the more of free memory is
2203 * unusable and by implication, the worse the external fragmentation is. This
2204 * can be expressed as a percentage by multiplying by 100.
2205 */
2206 static int unusable_show(struct seq_file *m, void *arg)
2207 {
2208 pg_data_t *pgdat = (pg_data_t *)arg;
2209
2210 /* check memoryless node */
2211 if (!node_state(pgdat->node_id, N_MEMORY))
2212 return 0;
2213
2214 walk_zones_in_node(m, pgdat, true, false, unusable_show_print);
2215
2216 return 0;
2217 }
2218
2219 static const struct seq_operations unusable_sops = {
2220 .start = frag_start,
2221 .next = frag_next,
2222 .stop = frag_stop,
2223 .show = unusable_show,
2224 };
2225
2226 DEFINE_SEQ_ATTRIBUTE(unusable);
2227
2228 static void extfrag_show_print(struct seq_file *m,
2229 pg_data_t *pgdat, struct zone *zone)
2230 {
2231 unsigned int order;
2232 int index;
2233
2234 /* Alloc on stack as interrupts are disabled for zone walk */
2235 struct contig_page_info info;
2236
2237 seq_printf(m, "Node %d, zone %8s ",
2238 pgdat->node_id,
2239 zone->name);
2240 for (order = 0; order < NR_PAGE_ORDERS; ++order) {
2241 fill_contig_page_info(zone, order, &info);
2242 index = __fragmentation_index(order, &info);
2243 seq_printf(m, "%2d.%03d ", index / 1000, index % 1000);
2244 }
2245
2246 seq_putc(m, '\n');
2247 }
2248
2249 /*
2250 * Display fragmentation index for orders that allocations would fail for
2251 */
2252 static int extfrag_show(struct seq_file *m, void *arg)
2253 {
2254 pg_data_t *pgdat = (pg_data_t *)arg;
2255
2256 walk_zones_in_node(m, pgdat, true, false, extfrag_show_print);
2257
2258 return 0;
2259 }
2260
2261 static const struct seq_operations extfrag_sops = {
2262 .start = frag_start,
2263 .next = frag_next,
2264 .stop = frag_stop,
2265 .show = extfrag_show,
2266 };
2267
2268 DEFINE_SEQ_ATTRIBUTE(extfrag);
2269
2270 static int __init extfrag_debug_init(void)
2271 {
2272 struct dentry *extfrag_debug_root;
2273
2274 extfrag_debug_root = debugfs_create_dir("extfrag", NULL);
2275
2276 debugfs_create_file("unusable_index", 0444, extfrag_debug_root, NULL,
2277 &unusable_fops);
2278
2279 debugfs_create_file("extfrag_index", 0444, extfrag_debug_root, NULL,
2280 &extfrag_fops);
2281
2282 return 0;
2283 }
2284
2285 module_init(extfrag_debug_init);
2286
2287 #endif
2288
2289 /*
2290 * Page metadata size (struct page and page_ext) in pages
2291 */
2292 static unsigned long early_perpage_metadata[MAX_NUMNODES] __meminitdata;
2293
2294 void __meminit mod_node_early_perpage_metadata(int nid, long delta)
2295 {
2296 early_perpage_metadata[nid] += delta;
2297 }
2298
2299 void __meminit store_early_perpage_metadata(void)
2300 {
2301 int nid;
2302 struct pglist_data *pgdat;
2303
2304 for_each_online_pgdat(pgdat) {
2305 nid = pgdat->node_id;
2306 mod_node_page_state(NODE_DATA(nid), NR_MEMMAP_BOOT,
2307 early_perpage_metadata[nid]);
2308 }
2309 }
2310
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