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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
32#include "internal.h"
33
34#define NUMA_STATS_THRESHOLD (U16_MAX - 2)
35
36#ifdef CONFIG_NUMA
37int sysctl_vm_numa_stat = ENABLE_NUMA_STAT;
38
39/* zero numa counters within a zone */
40static void zero_zone_numa_counters(struct zone *zone)
41{
42 int item, cpu;
43
44 for (item = 0; item < NR_VM_NUMA_STAT_ITEMS; item++) {
45 atomic_long_set(&zone->vm_numa_stat[item], 0);
46 for_each_online_cpu(cpu)
47 per_cpu_ptr(zone->pageset, cpu)->vm_numa_stat_diff[item]
48 = 0;
49 }
50}
51
52/* zero numa counters of all the populated zones */
53static 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 */
62static void zero_global_numa_counters(void)
63{
64 int item;
65
66 for (item = 0; item < NR_VM_NUMA_STAT_ITEMS; item++)
67 atomic_long_set(&vm_numa_stat[item], 0);
68}
69
70static void invalid_numa_statistics(void)
71{
72 zero_zones_numa_counters();
73 zero_global_numa_counters();
74}
75
76static DEFINE_MUTEX(vm_numa_stat_lock);
77
78int 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
101out:
102 mutex_unlock(&vm_numa_stat_lock);
103 return ret;
104}
105#endif
106
107#ifdef CONFIG_VM_EVENT_COUNTERS
108DEFINE_PER_CPU(struct vm_event_state, vm_event_states) = {{0}};
109EXPORT_PER_CPU_SYMBOL(vm_event_states);
110
111static 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*/
131void all_vm_events(unsigned long *ret)
132{
133 get_online_cpus();
134 sum_vm_events(ret);
135 put_online_cpus();
136}
137EXPORT_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 */
145void 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 */
163atomic_long_t vm_zone_stat[NR_VM_ZONE_STAT_ITEMS] __cacheline_aligned_in_smp;
164atomic_long_t vm_numa_stat[NR_VM_NUMA_STAT_ITEMS] __cacheline_aligned_in_smp;
165atomic_long_t vm_node_stat[NR_VM_NODE_STAT_ITEMS] __cacheline_aligned_in_smp;
166EXPORT_SYMBOL(vm_zone_stat);
167EXPORT_SYMBOL(vm_numa_stat);
168EXPORT_SYMBOL(vm_node_stat);
169
170#ifdef CONFIG_SMP
171
172int calculate_pressure_threshold(struct zone *zone)
173{
174 int threshold;
175 int watermark_distance;
176
177 /*
178 * As vmstats are not up to date, there is drift between the estimated
179 * and real values. For high thresholds and a high number of CPUs, it
180 * is possible for the min watermark to be breached while the estimated
181 * value looks fine. The pressure threshold is a reduced value such
182 * that even the maximum amount of drift will not accidentally breach
183 * the min watermark
184 */
185 watermark_distance = low_wmark_pages(zone) - min_wmark_pages(zone);
186 threshold = max(1, (int)(watermark_distance / num_online_cpus()));
187
188 /*
189 * Maximum threshold is 125
190 */
191 threshold = min(125, threshold);
192
193 return threshold;
194}
195
196int calculate_normal_threshold(struct zone *zone)
197{
198 int threshold;
199 int mem; /* memory in 128 MB units */
200
201 /*
202 * The threshold scales with the number of processors and the amount
203 * of memory per zone. More memory means that we can defer updates for
204 * longer, more processors could lead to more contention.
205 * fls() is used to have a cheap way of logarithmic scaling.
206 *
207 * Some sample thresholds:
208 *
209 * Threshold Processors (fls) Zonesize fls(mem+1)
210 * ------------------------------------------------------------------
211 * 8 1 1 0.9-1 GB 4
212 * 16 2 2 0.9-1 GB 4
213 * 20 2 2 1-2 GB 5
214 * 24 2 2 2-4 GB 6
215 * 28 2 2 4-8 GB 7
216 * 32 2 2 8-16 GB 8
217 * 4 2 2 <128M 1
218 * 30 4 3 2-4 GB 5
219 * 48 4 3 8-16 GB 8
220 * 32 8 4 1-2 GB 4
221 * 32 8 4 0.9-1GB 4
222 * 10 16 5 <128M 1
223 * 40 16 5 900M 4
224 * 70 64 7 2-4 GB 5
225 * 84 64 7 4-8 GB 6
226 * 108 512 9 4-8 GB 6
227 * 125 1024 10 8-16 GB 8
228 * 125 1024 10 16-32 GB 9
229 */
230
231 mem = zone_managed_pages(zone) >> (27 - PAGE_SHIFT);
232
233 threshold = 2 * fls(num_online_cpus()) * (1 + fls(mem));
234
235 /*
236 * Maximum threshold is 125
237 */
238 threshold = min(125, threshold);
239
240 return threshold;
241}
242
243/*
244 * Refresh the thresholds for each zone.
245 */
246void refresh_zone_stat_thresholds(void)
247{
248 struct pglist_data *pgdat;
249 struct zone *zone;
250 int cpu;
251 int threshold;
252
253 /* Zero current pgdat thresholds */
254 for_each_online_pgdat(pgdat) {
255 for_each_online_cpu(cpu) {
256 per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold = 0;
257 }
258 }
259
260 for_each_populated_zone(zone) {
261 struct pglist_data *pgdat = zone->zone_pgdat;
262 unsigned long max_drift, tolerate_drift;
263
264 threshold = calculate_normal_threshold(zone);
265
266 for_each_online_cpu(cpu) {
267 int pgdat_threshold;
268
269 per_cpu_ptr(zone->pageset, cpu)->stat_threshold
270 = threshold;
271
272 /* Base nodestat threshold on the largest populated zone. */
273 pgdat_threshold = per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold;
274 per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold
275 = max(threshold, pgdat_threshold);
276 }
277
278 /*
279 * Only set percpu_drift_mark if there is a danger that
280 * NR_FREE_PAGES reports the low watermark is ok when in fact
281 * the min watermark could be breached by an allocation
282 */
283 tolerate_drift = low_wmark_pages(zone) - min_wmark_pages(zone);
284 max_drift = num_online_cpus() * threshold;
285 if (max_drift > tolerate_drift)
286 zone->percpu_drift_mark = high_wmark_pages(zone) +
287 max_drift;
288 }
289}
290
291void set_pgdat_percpu_threshold(pg_data_t *pgdat,
292 int (*calculate_pressure)(struct zone *))
293{
294 struct zone *zone;
295 int cpu;
296 int threshold;
297 int i;
298
299 for (i = 0; i < pgdat->nr_zones; i++) {
300 zone = &pgdat->node_zones[i];
301 if (!zone->percpu_drift_mark)
302 continue;
303
304 threshold = (*calculate_pressure)(zone);
305 for_each_online_cpu(cpu)
306 per_cpu_ptr(zone->pageset, cpu)->stat_threshold
307 = threshold;
308 }
309}
310
311/*
312 * For use when we know that interrupts are disabled,
313 * or when we know that preemption is disabled and that
314 * particular counter cannot be updated from interrupt context.
315 */
316void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
317 long delta)
318{
319 struct per_cpu_pageset __percpu *pcp = zone->pageset;
320 s8 __percpu *p = pcp->vm_stat_diff + item;
321 long x;
322 long t;
323
324 x = delta + __this_cpu_read(*p);
325
326 t = __this_cpu_read(pcp->stat_threshold);
327
328 if (unlikely(x > t || x < -t)) {
329 zone_page_state_add(x, zone, item);
330 x = 0;
331 }
332 __this_cpu_write(*p, x);
333}
334EXPORT_SYMBOL(__mod_zone_page_state);
335
336void __mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
337 long delta)
338{
339 struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
340 s8 __percpu *p = pcp->vm_node_stat_diff + item;
341 long x;
342 long t;
343
344 if (vmstat_item_in_bytes(item)) {
345 VM_WARN_ON_ONCE(delta & (PAGE_SIZE - 1));
346 delta >>= PAGE_SHIFT;
347 }
348
349 x = delta + __this_cpu_read(*p);
350
351 t = __this_cpu_read(pcp->stat_threshold);
352
353 if (unlikely(x > t || x < -t)) {
354 node_page_state_add(x, pgdat, item);
355 x = 0;
356 }
357 __this_cpu_write(*p, x);
358}
359EXPORT_SYMBOL(__mod_node_page_state);
360
361/*
362 * Optimized increment and decrement functions.
363 *
364 * These are only for a single page and therefore can take a struct page *
365 * argument instead of struct zone *. This allows the inclusion of the code
366 * generated for page_zone(page) into the optimized functions.
367 *
368 * No overflow check is necessary and therefore the differential can be
369 * incremented or decremented in place which may allow the compilers to
370 * generate better code.
371 * The increment or decrement is known and therefore one boundary check can
372 * be omitted.
373 *
374 * NOTE: These functions are very performance sensitive. Change only
375 * with care.
376 *
377 * Some processors have inc/dec instructions that are atomic vs an interrupt.
378 * However, the code must first determine the differential location in a zone
379 * based on the processor number and then inc/dec the counter. There is no
380 * guarantee without disabling preemption that the processor will not change
381 * in between and therefore the atomicity vs. interrupt cannot be exploited
382 * in a useful way here.
383 */
384void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
385{
386 struct per_cpu_pageset __percpu *pcp = zone->pageset;
387 s8 __percpu *p = pcp->vm_stat_diff + item;
388 s8 v, t;
389
390 v = __this_cpu_inc_return(*p);
391 t = __this_cpu_read(pcp->stat_threshold);
392 if (unlikely(v > t)) {
393 s8 overstep = t >> 1;
394
395 zone_page_state_add(v + overstep, zone, item);
396 __this_cpu_write(*p, -overstep);
397 }
398}
399
400void __inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
401{
402 struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
403 s8 __percpu *p = pcp->vm_node_stat_diff + item;
404 s8 v, t;
405
406 VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
407
408 v = __this_cpu_inc_return(*p);
409 t = __this_cpu_read(pcp->stat_threshold);
410 if (unlikely(v > t)) {
411 s8 overstep = t >> 1;
412
413 node_page_state_add(v + overstep, pgdat, item);
414 __this_cpu_write(*p, -overstep);
415 }
416}
417
418void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
419{
420 __inc_zone_state(page_zone(page), item);
421}
422EXPORT_SYMBOL(__inc_zone_page_state);
423
424void __inc_node_page_state(struct page *page, enum node_stat_item item)
425{
426 __inc_node_state(page_pgdat(page), item);
427}
428EXPORT_SYMBOL(__inc_node_page_state);
429
430void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
431{
432 struct per_cpu_pageset __percpu *pcp = zone->pageset;
433 s8 __percpu *p = pcp->vm_stat_diff + item;
434 s8 v, t;
435
436 v = __this_cpu_dec_return(*p);
437 t = __this_cpu_read(pcp->stat_threshold);
438 if (unlikely(v < - t)) {
439 s8 overstep = t >> 1;
440
441 zone_page_state_add(v - overstep, zone, item);
442 __this_cpu_write(*p, overstep);
443 }
444}
445
446void __dec_node_state(struct pglist_data *pgdat, enum node_stat_item item)
447{
448 struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
449 s8 __percpu *p = pcp->vm_node_stat_diff + item;
450 s8 v, t;
451
452 VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
453
454 v = __this_cpu_dec_return(*p);
455 t = __this_cpu_read(pcp->stat_threshold);
456 if (unlikely(v < - t)) {
457 s8 overstep = t >> 1;
458
459 node_page_state_add(v - overstep, pgdat, item);
460 __this_cpu_write(*p, overstep);
461 }
462}
463
464void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
465{
466 __dec_zone_state(page_zone(page), item);
467}
468EXPORT_SYMBOL(__dec_zone_page_state);
469
470void __dec_node_page_state(struct page *page, enum node_stat_item item)
471{
472 __dec_node_state(page_pgdat(page), item);
473}
474EXPORT_SYMBOL(__dec_node_page_state);
475
476#ifdef CONFIG_HAVE_CMPXCHG_LOCAL
477/*
478 * If we have cmpxchg_local support then we do not need to incur the overhead
479 * that comes with local_irq_save/restore if we use this_cpu_cmpxchg.
480 *
481 * mod_state() modifies the zone counter state through atomic per cpu
482 * operations.
483 *
484 * Overstep mode specifies how overstep should handled:
485 * 0 No overstepping
486 * 1 Overstepping half of threshold
487 * -1 Overstepping minus half of threshold
488*/
489static inline void mod_zone_state(struct zone *zone,
490 enum zone_stat_item item, long delta, int overstep_mode)
491{
492 struct per_cpu_pageset __percpu *pcp = zone->pageset;
493 s8 __percpu *p = pcp->vm_stat_diff + item;
494 long o, n, t, z;
495
496 do {
497 z = 0; /* overflow to zone counters */
498
499 /*
500 * The fetching of the stat_threshold is racy. We may apply
501 * a counter threshold to the wrong the cpu if we get
502 * rescheduled while executing here. However, the next
503 * counter update will apply the threshold again and
504 * therefore bring the counter under the threshold again.
505 *
506 * Most of the time the thresholds are the same anyways
507 * for all cpus in a zone.
508 */
509 t = this_cpu_read(pcp->stat_threshold);
510
511 o = this_cpu_read(*p);
512 n = delta + o;
513
514 if (n > t || n < -t) {
515 int os = overstep_mode * (t >> 1) ;
516
517 /* Overflow must be added to zone counters */
518 z = n + os;
519 n = -os;
520 }
521 } while (this_cpu_cmpxchg(*p, o, n) != o);
522
523 if (z)
524 zone_page_state_add(z, zone, item);
525}
526
527void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
528 long delta)
529{
530 mod_zone_state(zone, item, delta, 0);
531}
532EXPORT_SYMBOL(mod_zone_page_state);
533
534void inc_zone_page_state(struct page *page, enum zone_stat_item item)
535{
536 mod_zone_state(page_zone(page), item, 1, 1);
537}
538EXPORT_SYMBOL(inc_zone_page_state);
539
540void dec_zone_page_state(struct page *page, enum zone_stat_item item)
541{
542 mod_zone_state(page_zone(page), item, -1, -1);
543}
544EXPORT_SYMBOL(dec_zone_page_state);
545
546static inline void mod_node_state(struct pglist_data *pgdat,
547 enum node_stat_item item, int delta, int overstep_mode)
548{
549 struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
550 s8 __percpu *p = pcp->vm_node_stat_diff + item;
551 long o, n, t, z;
552
553 if (vmstat_item_in_bytes(item)) {
554 VM_WARN_ON_ONCE(delta & (PAGE_SIZE - 1));
555 delta >>= PAGE_SHIFT;
556 }
557
558 do {
559 z = 0; /* overflow to node counters */
560
561 /*
562 * The fetching of the stat_threshold is racy. We may apply
563 * a counter threshold to the wrong the cpu if we get
564 * rescheduled while executing here. However, the next
565 * counter update will apply the threshold again and
566 * therefore bring the counter under the threshold again.
567 *
568 * Most of the time the thresholds are the same anyways
569 * for all cpus in a node.
570 */
571 t = this_cpu_read(pcp->stat_threshold);
572
573 o = this_cpu_read(*p);
574 n = delta + o;
575
576 if (n > t || n < -t) {
577 int os = overstep_mode * (t >> 1) ;
578
579 /* Overflow must be added to node counters */
580 z = n + os;
581 n = -os;
582 }
583 } while (this_cpu_cmpxchg(*p, o, n) != o);
584
585 if (z)
586 node_page_state_add(z, pgdat, item);
587}
588
589void mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
590 long delta)
591{
592 mod_node_state(pgdat, item, delta, 0);
593}
594EXPORT_SYMBOL(mod_node_page_state);
595
596void inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
597{
598 mod_node_state(pgdat, item, 1, 1);
599}
600
601void inc_node_page_state(struct page *page, enum node_stat_item item)
602{
603 mod_node_state(page_pgdat(page), item, 1, 1);
604}
605EXPORT_SYMBOL(inc_node_page_state);
606
607void dec_node_page_state(struct page *page, enum node_stat_item item)
608{
609 mod_node_state(page_pgdat(page), item, -1, -1);
610}
611EXPORT_SYMBOL(dec_node_page_state);
612#else
613/*
614 * Use interrupt disable to serialize counter updates
615 */
616void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
617 long delta)
618{
619 unsigned long flags;
620
621 local_irq_save(flags);
622 __mod_zone_page_state(zone, item, delta);
623 local_irq_restore(flags);
624}
625EXPORT_SYMBOL(mod_zone_page_state);
626
627void inc_zone_page_state(struct page *page, enum zone_stat_item item)
628{
629 unsigned long flags;
630 struct zone *zone;
631
632 zone = page_zone(page);
633 local_irq_save(flags);
634 __inc_zone_state(zone, item);
635 local_irq_restore(flags);
636}
637EXPORT_SYMBOL(inc_zone_page_state);
638
639void dec_zone_page_state(struct page *page, enum zone_stat_item item)
640{
641 unsigned long flags;
642
643 local_irq_save(flags);
644 __dec_zone_page_state(page, item);
645 local_irq_restore(flags);
646}
647EXPORT_SYMBOL(dec_zone_page_state);
648
649void inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
650{
651 unsigned long flags;
652
653 local_irq_save(flags);
654 __inc_node_state(pgdat, item);
655 local_irq_restore(flags);
656}
657EXPORT_SYMBOL(inc_node_state);
658
659void mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
660 long delta)
661{
662 unsigned long flags;
663
664 local_irq_save(flags);
665 __mod_node_page_state(pgdat, item, delta);
666 local_irq_restore(flags);
667}
668EXPORT_SYMBOL(mod_node_page_state);
669
670void inc_node_page_state(struct page *page, enum node_stat_item item)
671{
672 unsigned long flags;
673 struct pglist_data *pgdat;
674
675 pgdat = page_pgdat(page);
676 local_irq_save(flags);
677 __inc_node_state(pgdat, item);
678 local_irq_restore(flags);
679}
680EXPORT_SYMBOL(inc_node_page_state);
681
682void dec_node_page_state(struct page *page, enum node_stat_item item)
683{
684 unsigned long flags;
685
686 local_irq_save(flags);
687 __dec_node_page_state(page, item);
688 local_irq_restore(flags);
689}
690EXPORT_SYMBOL(dec_node_page_state);
691#endif
692
693/*
694 * Fold a differential into the global counters.
695 * Returns the number of counters updated.
696 */
697#ifdef CONFIG_NUMA
698static int fold_diff(int *zone_diff, int *numa_diff, int *node_diff)
699{
700 int i;
701 int changes = 0;
702
703 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
704 if (zone_diff[i]) {
705 atomic_long_add(zone_diff[i], &vm_zone_stat[i]);
706 changes++;
707 }
708
709 for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
710 if (numa_diff[i]) {
711 atomic_long_add(numa_diff[i], &vm_numa_stat[i]);
712 changes++;
713 }
714
715 for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
716 if (node_diff[i]) {
717 atomic_long_add(node_diff[i], &vm_node_stat[i]);
718 changes++;
719 }
720 return changes;
721}
722#else
723static int fold_diff(int *zone_diff, int *node_diff)
724{
725 int i;
726 int changes = 0;
727
728 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
729 if (zone_diff[i]) {
730 atomic_long_add(zone_diff[i], &vm_zone_stat[i]);
731 changes++;
732 }
733
734 for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
735 if (node_diff[i]) {
736 atomic_long_add(node_diff[i], &vm_node_stat[i]);
737 changes++;
738 }
739 return changes;
740}
741#endif /* CONFIG_NUMA */
742
743/*
744 * Update the zone counters for the current cpu.
745 *
746 * Note that refresh_cpu_vm_stats strives to only access
747 * node local memory. The per cpu pagesets on remote zones are placed
748 * in the memory local to the processor using that pageset. So the
749 * loop over all zones will access a series of cachelines local to
750 * the processor.
751 *
752 * The call to zone_page_state_add updates the cachelines with the
753 * statistics in the remote zone struct as well as the global cachelines
754 * with the global counters. These could cause remote node cache line
755 * bouncing and will have to be only done when necessary.
756 *
757 * The function returns the number of global counters updated.
758 */
759static int refresh_cpu_vm_stats(bool do_pagesets)
760{
761 struct pglist_data *pgdat;
762 struct zone *zone;
763 int i;
764 int global_zone_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
765#ifdef CONFIG_NUMA
766 int global_numa_diff[NR_VM_NUMA_STAT_ITEMS] = { 0, };
767#endif
768 int global_node_diff[NR_VM_NODE_STAT_ITEMS] = { 0, };
769 int changes = 0;
770
771 for_each_populated_zone(zone) {
772 struct per_cpu_pageset __percpu *p = zone->pageset;
773
774 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
775 int v;
776
777 v = this_cpu_xchg(p->vm_stat_diff[i], 0);
778 if (v) {
779
780 atomic_long_add(v, &zone->vm_stat[i]);
781 global_zone_diff[i] += v;
782#ifdef CONFIG_NUMA
783 /* 3 seconds idle till flush */
784 __this_cpu_write(p->expire, 3);
785#endif
786 }
787 }
788#ifdef CONFIG_NUMA
789 for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++) {
790 int v;
791
792 v = this_cpu_xchg(p->vm_numa_stat_diff[i], 0);
793 if (v) {
794
795 atomic_long_add(v, &zone->vm_numa_stat[i]);
796 global_numa_diff[i] += v;
797 __this_cpu_write(p->expire, 3);
798 }
799 }
800
801 if (do_pagesets) {
802 cond_resched();
803 /*
804 * Deal with draining the remote pageset of this
805 * processor
806 *
807 * Check if there are pages remaining in this pageset
808 * if not then there is nothing to expire.
809 */
810 if (!__this_cpu_read(p->expire) ||
811 !__this_cpu_read(p->pcp.count))
812 continue;
813
814 /*
815 * We never drain zones local to this processor.
816 */
817 if (zone_to_nid(zone) == numa_node_id()) {
818 __this_cpu_write(p->expire, 0);
819 continue;
820 }
821
822 if (__this_cpu_dec_return(p->expire))
823 continue;
824
825 if (__this_cpu_read(p->pcp.count)) {
826 drain_zone_pages(zone, this_cpu_ptr(&p->pcp));
827 changes++;
828 }
829 }
830#endif
831 }
832
833 for_each_online_pgdat(pgdat) {
834 struct per_cpu_nodestat __percpu *p = pgdat->per_cpu_nodestats;
835
836 for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
837 int v;
838
839 v = this_cpu_xchg(p->vm_node_stat_diff[i], 0);
840 if (v) {
841 atomic_long_add(v, &pgdat->vm_stat[i]);
842 global_node_diff[i] += v;
843 }
844 }
845 }
846
847#ifdef CONFIG_NUMA
848 changes += fold_diff(global_zone_diff, global_numa_diff,
849 global_node_diff);
850#else
851 changes += fold_diff(global_zone_diff, global_node_diff);
852#endif
853 return changes;
854}
855
856/*
857 * Fold the data for an offline cpu into the global array.
858 * There cannot be any access by the offline cpu and therefore
859 * synchronization is simplified.
860 */
861void cpu_vm_stats_fold(int cpu)
862{
863 struct pglist_data *pgdat;
864 struct zone *zone;
865 int i;
866 int global_zone_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
867#ifdef CONFIG_NUMA
868 int global_numa_diff[NR_VM_NUMA_STAT_ITEMS] = { 0, };
869#endif
870 int global_node_diff[NR_VM_NODE_STAT_ITEMS] = { 0, };
871
872 for_each_populated_zone(zone) {
873 struct per_cpu_pageset *p;
874
875 p = per_cpu_ptr(zone->pageset, cpu);
876
877 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
878 if (p->vm_stat_diff[i]) {
879 int v;
880
881 v = p->vm_stat_diff[i];
882 p->vm_stat_diff[i] = 0;
883 atomic_long_add(v, &zone->vm_stat[i]);
884 global_zone_diff[i] += v;
885 }
886
887#ifdef CONFIG_NUMA
888 for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
889 if (p->vm_numa_stat_diff[i]) {
890 int v;
891
892 v = p->vm_numa_stat_diff[i];
893 p->vm_numa_stat_diff[i] = 0;
894 atomic_long_add(v, &zone->vm_numa_stat[i]);
895 global_numa_diff[i] += v;
896 }
897#endif
898 }
899
900 for_each_online_pgdat(pgdat) {
901 struct per_cpu_nodestat *p;
902
903 p = per_cpu_ptr(pgdat->per_cpu_nodestats, cpu);
904
905 for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
906 if (p->vm_node_stat_diff[i]) {
907 int v;
908
909 v = p->vm_node_stat_diff[i];
910 p->vm_node_stat_diff[i] = 0;
911 atomic_long_add(v, &pgdat->vm_stat[i]);
912 global_node_diff[i] += v;
913 }
914 }
915
916#ifdef CONFIG_NUMA
917 fold_diff(global_zone_diff, global_numa_diff, global_node_diff);
918#else
919 fold_diff(global_zone_diff, global_node_diff);
920#endif
921}
922
923/*
924 * this is only called if !populated_zone(zone), which implies no other users of
925 * pset->vm_stat_diff[] exsist.
926 */
927void drain_zonestat(struct zone *zone, struct per_cpu_pageset *pset)
928{
929 int i;
930
931 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
932 if (pset->vm_stat_diff[i]) {
933 int v = pset->vm_stat_diff[i];
934 pset->vm_stat_diff[i] = 0;
935 atomic_long_add(v, &zone->vm_stat[i]);
936 atomic_long_add(v, &vm_zone_stat[i]);
937 }
938
939#ifdef CONFIG_NUMA
940 for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
941 if (pset->vm_numa_stat_diff[i]) {
942 int v = pset->vm_numa_stat_diff[i];
943
944 pset->vm_numa_stat_diff[i] = 0;
945 atomic_long_add(v, &zone->vm_numa_stat[i]);
946 atomic_long_add(v, &vm_numa_stat[i]);
947 }
948#endif
949}
950#endif
951
952#ifdef CONFIG_NUMA
953void __inc_numa_state(struct zone *zone,
954 enum numa_stat_item item)
955{
956 struct per_cpu_pageset __percpu *pcp = zone->pageset;
957 u16 __percpu *p = pcp->vm_numa_stat_diff + item;
958 u16 v;
959
960 v = __this_cpu_inc_return(*p);
961
962 if (unlikely(v > NUMA_STATS_THRESHOLD)) {
963 zone_numa_state_add(v, zone, item);
964 __this_cpu_write(*p, 0);
965 }
966}
967
968/*
969 * Determine the per node value of a stat item. This function
970 * is called frequently in a NUMA machine, so try to be as
971 * frugal as possible.
972 */
973unsigned long sum_zone_node_page_state(int node,
974 enum zone_stat_item item)
975{
976 struct zone *zones = NODE_DATA(node)->node_zones;
977 int i;
978 unsigned long count = 0;
979
980 for (i = 0; i < MAX_NR_ZONES; i++)
981 count += zone_page_state(zones + i, item);
982
983 return count;
984}
985
986/*
987 * Determine the per node value of a numa stat item. To avoid deviation,
988 * the per cpu stat number in vm_numa_stat_diff[] is also included.
989 */
990unsigned long sum_zone_numa_state(int node,
991 enum numa_stat_item item)
992{
993 struct zone *zones = NODE_DATA(node)->node_zones;
994 int i;
995 unsigned long count = 0;
996
997 for (i = 0; i < MAX_NR_ZONES; i++)
998 count += zone_numa_state_snapshot(zones + i, item);
999
1000 return count;
1001}
1002
1003/*
1004 * Determine the per node value of a stat item.
1005 */
1006unsigned long node_page_state_pages(struct pglist_data *pgdat,
1007 enum node_stat_item item)
1008{
1009 long x = atomic_long_read(&pgdat->vm_stat[item]);
1010#ifdef CONFIG_SMP
1011 if (x < 0)
1012 x = 0;
1013#endif
1014 return x;
1015}
1016
1017unsigned long node_page_state(struct pglist_data *pgdat,
1018 enum node_stat_item item)
1019{
1020 VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
1021
1022 return node_page_state_pages(pgdat, item);
1023}
1024#endif
1025
1026#ifdef CONFIG_COMPACTION
1027
1028struct contig_page_info {
1029 unsigned long free_pages;
1030 unsigned long free_blocks_total;
1031 unsigned long free_blocks_suitable;
1032};
1033
1034/*
1035 * Calculate the number of free pages in a zone, how many contiguous
1036 * pages are free and how many are large enough to satisfy an allocation of
1037 * the target size. Note that this function makes no attempt to estimate
1038 * how many suitable free blocks there *might* be if MOVABLE pages were
1039 * migrated. Calculating that is possible, but expensive and can be
1040 * figured out from userspace
1041 */
1042static void fill_contig_page_info(struct zone *zone,
1043 unsigned int suitable_order,
1044 struct contig_page_info *info)
1045{
1046 unsigned int order;
1047
1048 info->free_pages = 0;
1049 info->free_blocks_total = 0;
1050 info->free_blocks_suitable = 0;
1051
1052 for (order = 0; order < MAX_ORDER; order++) {
1053 unsigned long blocks;
1054
1055 /* Count number of free blocks */
1056 blocks = zone->free_area[order].nr_free;
1057 info->free_blocks_total += blocks;
1058
1059 /* Count free base pages */
1060 info->free_pages += blocks << order;
1061
1062 /* Count the suitable free blocks */
1063 if (order >= suitable_order)
1064 info->free_blocks_suitable += blocks <<
1065 (order - suitable_order);
1066 }
1067}
1068
1069/*
1070 * A fragmentation index only makes sense if an allocation of a requested
1071 * size would fail. If that is true, the fragmentation index indicates
1072 * whether external fragmentation or a lack of memory was the problem.
1073 * The value can be used to determine if page reclaim or compaction
1074 * should be used
1075 */
1076static int __fragmentation_index(unsigned int order, struct contig_page_info *info)
1077{
1078 unsigned long requested = 1UL << order;
1079
1080 if (WARN_ON_ONCE(order >= MAX_ORDER))
1081 return 0;
1082
1083 if (!info->free_blocks_total)
1084 return 0;
1085
1086 /* Fragmentation index only makes sense when a request would fail */
1087 if (info->free_blocks_suitable)
1088 return -1000;
1089
1090 /*
1091 * Index is between 0 and 1 so return within 3 decimal places
1092 *
1093 * 0 => allocation would fail due to lack of memory
1094 * 1 => allocation would fail due to fragmentation
1095 */
1096 return 1000 - div_u64( (1000+(div_u64(info->free_pages * 1000ULL, requested))), info->free_blocks_total);
1097}
1098
1099/*
1100 * Calculates external fragmentation within a zone wrt the given order.
1101 * It is defined as the percentage of pages found in blocks of size
1102 * less than 1 << order. It returns values in range [0, 100].
1103 */
1104unsigned int extfrag_for_order(struct zone *zone, unsigned int order)
1105{
1106 struct contig_page_info info;
1107
1108 fill_contig_page_info(zone, order, &info);
1109 if (info.free_pages == 0)
1110 return 0;
1111
1112 return div_u64((info.free_pages -
1113 (info.free_blocks_suitable << order)) * 100,
1114 info.free_pages);
1115}
1116
1117/* Same as __fragmentation index but allocs contig_page_info on stack */
1118int fragmentation_index(struct zone *zone, unsigned int order)
1119{
1120 struct contig_page_info info;
1121
1122 fill_contig_page_info(zone, order, &info);
1123 return __fragmentation_index(order, &info);
1124}
1125#endif
1126
1127#if defined(CONFIG_PROC_FS) || defined(CONFIG_SYSFS) || \
1128 defined(CONFIG_NUMA) || defined(CONFIG_MEMCG)
1129#ifdef CONFIG_ZONE_DMA
1130#define TEXT_FOR_DMA(xx) xx "_dma",
1131#else
1132#define TEXT_FOR_DMA(xx)
1133#endif
1134
1135#ifdef CONFIG_ZONE_DMA32
1136#define TEXT_FOR_DMA32(xx) xx "_dma32",
1137#else
1138#define TEXT_FOR_DMA32(xx)
1139#endif
1140
1141#ifdef CONFIG_HIGHMEM
1142#define TEXT_FOR_HIGHMEM(xx) xx "_high",
1143#else
1144#define TEXT_FOR_HIGHMEM(xx)
1145#endif
1146
1147#define TEXTS_FOR_ZONES(xx) TEXT_FOR_DMA(xx) TEXT_FOR_DMA32(xx) xx "_normal", \
1148 TEXT_FOR_HIGHMEM(xx) xx "_movable",
1149
1150const char * const vmstat_text[] = {
1151 /* enum zone_stat_item counters */
1152 "nr_free_pages",
1153 "nr_zone_inactive_anon",
1154 "nr_zone_active_anon",
1155 "nr_zone_inactive_file",
1156 "nr_zone_active_file",
1157 "nr_zone_unevictable",
1158 "nr_zone_write_pending",
1159 "nr_mlock",
1160 "nr_page_table_pages",
1161 "nr_bounce",
1162#if IS_ENABLED(CONFIG_ZSMALLOC)
1163 "nr_zspages",
1164#endif
1165 "nr_free_cma",
1166
1167 /* enum numa_stat_item counters */
1168#ifdef CONFIG_NUMA
1169 "numa_hit",
1170 "numa_miss",
1171 "numa_foreign",
1172 "numa_interleave",
1173 "numa_local",
1174 "numa_other",
1175#endif
1176
1177 /* enum node_stat_item counters */
1178 "nr_inactive_anon",
1179 "nr_active_anon",
1180 "nr_inactive_file",
1181 "nr_active_file",
1182 "nr_unevictable",
1183 "nr_slab_reclaimable",
1184 "nr_slab_unreclaimable",
1185 "nr_isolated_anon",
1186 "nr_isolated_file",
1187 "workingset_nodes",
1188 "workingset_refault_anon",
1189 "workingset_refault_file",
1190 "workingset_activate_anon",
1191 "workingset_activate_file",
1192 "workingset_restore_anon",
1193 "workingset_restore_file",
1194 "workingset_nodereclaim",
1195 "nr_anon_pages",
1196 "nr_mapped",
1197 "nr_file_pages",
1198 "nr_dirty",
1199 "nr_writeback",
1200 "nr_writeback_temp",
1201 "nr_shmem",
1202 "nr_shmem_hugepages",
1203 "nr_shmem_pmdmapped",
1204 "nr_file_hugepages",
1205 "nr_file_pmdmapped",
1206 "nr_anon_transparent_hugepages",
1207 "nr_vmscan_write",
1208 "nr_vmscan_immediate_reclaim",
1209 "nr_dirtied",
1210 "nr_written",
1211 "nr_kernel_misc_reclaimable",
1212 "nr_foll_pin_acquired",
1213 "nr_foll_pin_released",
1214 "nr_kernel_stack",
1215#if IS_ENABLED(CONFIG_SHADOW_CALL_STACK)
1216 "nr_shadow_call_stack",
1217#endif
1218
1219 /* enum writeback_stat_item counters */
1220 "nr_dirty_threshold",
1221 "nr_dirty_background_threshold",
1222
1223#if defined(CONFIG_VM_EVENT_COUNTERS) || defined(CONFIG_MEMCG)
1224 /* enum vm_event_item counters */
1225 "pgpgin",
1226 "pgpgout",
1227 "pswpin",
1228 "pswpout",
1229
1230 TEXTS_FOR_ZONES("pgalloc")
1231 TEXTS_FOR_ZONES("allocstall")
1232 TEXTS_FOR_ZONES("pgskip")
1233
1234 "pgfree",
1235 "pgactivate",
1236 "pgdeactivate",
1237 "pglazyfree",
1238
1239 "pgfault",
1240 "pgmajfault",
1241 "pglazyfreed",
1242
1243 "pgrefill",
1244 "pgreuse",
1245 "pgsteal_kswapd",
1246 "pgsteal_direct",
1247 "pgscan_kswapd",
1248 "pgscan_direct",
1249 "pgscan_direct_throttle",
1250 "pgscan_anon",
1251 "pgscan_file",
1252 "pgsteal_anon",
1253 "pgsteal_file",
1254
1255#ifdef CONFIG_NUMA
1256 "zone_reclaim_failed",
1257#endif
1258 "pginodesteal",
1259 "slabs_scanned",
1260 "kswapd_inodesteal",
1261 "kswapd_low_wmark_hit_quickly",
1262 "kswapd_high_wmark_hit_quickly",
1263 "pageoutrun",
1264
1265 "pgrotated",
1266
1267 "drop_pagecache",
1268 "drop_slab",
1269 "oom_kill",
1270
1271#ifdef CONFIG_NUMA_BALANCING
1272 "numa_pte_updates",
1273 "numa_huge_pte_updates",
1274 "numa_hint_faults",
1275 "numa_hint_faults_local",
1276 "numa_pages_migrated",
1277#endif
1278#ifdef CONFIG_MIGRATION
1279 "pgmigrate_success",
1280 "pgmigrate_fail",
1281 "thp_migration_success",
1282 "thp_migration_fail",
1283 "thp_migration_split",
1284#endif
1285#ifdef CONFIG_COMPACTION
1286 "compact_migrate_scanned",
1287 "compact_free_scanned",
1288 "compact_isolated",
1289 "compact_stall",
1290 "compact_fail",
1291 "compact_success",
1292 "compact_daemon_wake",
1293 "compact_daemon_migrate_scanned",
1294 "compact_daemon_free_scanned",
1295#endif
1296
1297#ifdef CONFIG_HUGETLB_PAGE
1298 "htlb_buddy_alloc_success",
1299 "htlb_buddy_alloc_fail",
1300#endif
1301 "unevictable_pgs_culled",
1302 "unevictable_pgs_scanned",
1303 "unevictable_pgs_rescued",
1304 "unevictable_pgs_mlocked",
1305 "unevictable_pgs_munlocked",
1306 "unevictable_pgs_cleared",
1307 "unevictable_pgs_stranded",
1308
1309#ifdef CONFIG_TRANSPARENT_HUGEPAGE
1310 "thp_fault_alloc",
1311 "thp_fault_fallback",
1312 "thp_fault_fallback_charge",
1313 "thp_collapse_alloc",
1314 "thp_collapse_alloc_failed",
1315 "thp_file_alloc",
1316 "thp_file_fallback",
1317 "thp_file_fallback_charge",
1318 "thp_file_mapped",
1319 "thp_split_page",
1320 "thp_split_page_failed",
1321 "thp_deferred_split_page",
1322 "thp_split_pmd",
1323#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
1324 "thp_split_pud",
1325#endif
1326 "thp_zero_page_alloc",
1327 "thp_zero_page_alloc_failed",
1328 "thp_swpout",
1329 "thp_swpout_fallback",
1330#endif
1331#ifdef CONFIG_MEMORY_BALLOON
1332 "balloon_inflate",
1333 "balloon_deflate",
1334#ifdef CONFIG_BALLOON_COMPACTION
1335 "balloon_migrate",
1336#endif
1337#endif /* CONFIG_MEMORY_BALLOON */
1338#ifdef CONFIG_DEBUG_TLBFLUSH
1339 "nr_tlb_remote_flush",
1340 "nr_tlb_remote_flush_received",
1341 "nr_tlb_local_flush_all",
1342 "nr_tlb_local_flush_one",
1343#endif /* CONFIG_DEBUG_TLBFLUSH */
1344
1345#ifdef CONFIG_DEBUG_VM_VMACACHE
1346 "vmacache_find_calls",
1347 "vmacache_find_hits",
1348#endif
1349#ifdef CONFIG_SWAP
1350 "swap_ra",
1351 "swap_ra_hit",
1352#endif
1353#endif /* CONFIG_VM_EVENT_COUNTERS || CONFIG_MEMCG */
1354};
1355#endif /* CONFIG_PROC_FS || CONFIG_SYSFS || CONFIG_NUMA || CONFIG_MEMCG */
1356
1357#if (defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)) || \
1358 defined(CONFIG_PROC_FS)
1359static void *frag_start(struct seq_file *m, loff_t *pos)
1360{
1361 pg_data_t *pgdat;
1362 loff_t node = *pos;
1363
1364 for (pgdat = first_online_pgdat();
1365 pgdat && node;
1366 pgdat = next_online_pgdat(pgdat))
1367 --node;
1368
1369 return pgdat;
1370}
1371
1372static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
1373{
1374 pg_data_t *pgdat = (pg_data_t *)arg;
1375
1376 (*pos)++;
1377 return next_online_pgdat(pgdat);
1378}
1379
1380static void frag_stop(struct seq_file *m, void *arg)
1381{
1382}
1383
1384/*
1385 * Walk zones in a node and print using a callback.
1386 * If @assert_populated is true, only use callback for zones that are populated.
1387 */
1388static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat,
1389 bool assert_populated, bool nolock,
1390 void (*print)(struct seq_file *m, pg_data_t *, struct zone *))
1391{
1392 struct zone *zone;
1393 struct zone *node_zones = pgdat->node_zones;
1394 unsigned long flags;
1395
1396 for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
1397 if (assert_populated && !populated_zone(zone))
1398 continue;
1399
1400 if (!nolock)
1401 spin_lock_irqsave(&zone->lock, flags);
1402 print(m, pgdat, zone);
1403 if (!nolock)
1404 spin_unlock_irqrestore(&zone->lock, flags);
1405 }
1406}
1407#endif
1408
1409#ifdef CONFIG_PROC_FS
1410static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,
1411 struct zone *zone)
1412{
1413 int order;
1414
1415 seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
1416 for (order = 0; order < MAX_ORDER; ++order)
1417 seq_printf(m, "%6lu ", zone->free_area[order].nr_free);
1418 seq_putc(m, '\n');
1419}
1420
1421/*
1422 * This walks the free areas for each zone.
1423 */
1424static int frag_show(struct seq_file *m, void *arg)
1425{
1426 pg_data_t *pgdat = (pg_data_t *)arg;
1427 walk_zones_in_node(m, pgdat, true, false, frag_show_print);
1428 return 0;
1429}
1430
1431static void pagetypeinfo_showfree_print(struct seq_file *m,
1432 pg_data_t *pgdat, struct zone *zone)
1433{
1434 int order, mtype;
1435
1436 for (mtype = 0; mtype < MIGRATE_TYPES; mtype++) {
1437 seq_printf(m, "Node %4d, zone %8s, type %12s ",
1438 pgdat->node_id,
1439 zone->name,
1440 migratetype_names[mtype]);
1441 for (order = 0; order < MAX_ORDER; ++order) {
1442 unsigned long freecount = 0;
1443 struct free_area *area;
1444 struct list_head *curr;
1445 bool overflow = false;
1446
1447 area = &(zone->free_area[order]);
1448
1449 list_for_each(curr, &area->free_list[mtype]) {
1450 /*
1451 * Cap the free_list iteration because it might
1452 * be really large and we are under a spinlock
1453 * so a long time spent here could trigger a
1454 * hard lockup detector. Anyway this is a
1455 * debugging tool so knowing there is a handful
1456 * of pages of this order should be more than
1457 * sufficient.
1458 */
1459 if (++freecount >= 100000) {
1460 overflow = true;
1461 break;
1462 }
1463 }
1464 seq_printf(m, "%s%6lu ", overflow ? ">" : "", freecount);
1465 spin_unlock_irq(&zone->lock);
1466 cond_resched();
1467 spin_lock_irq(&zone->lock);
1468 }
1469 seq_putc(m, '\n');
1470 }
1471}
1472
1473/* Print out the free pages at each order for each migatetype */
1474static int pagetypeinfo_showfree(struct seq_file *m, void *arg)
1475{
1476 int order;
1477 pg_data_t *pgdat = (pg_data_t *)arg;
1478
1479 /* Print header */
1480 seq_printf(m, "%-43s ", "Free pages count per migrate type at order");
1481 for (order = 0; order < MAX_ORDER; ++order)
1482 seq_printf(m, "%6d ", order);
1483 seq_putc(m, '\n');
1484
1485 walk_zones_in_node(m, pgdat, true, false, pagetypeinfo_showfree_print);
1486
1487 return 0;
1488}
1489
1490static void pagetypeinfo_showblockcount_print(struct seq_file *m,
1491 pg_data_t *pgdat, struct zone *zone)
1492{
1493 int mtype;
1494 unsigned long pfn;
1495 unsigned long start_pfn = zone->zone_start_pfn;
1496 unsigned long end_pfn = zone_end_pfn(zone);
1497 unsigned long count[MIGRATE_TYPES] = { 0, };
1498
1499 for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
1500 struct page *page;
1501
1502 page = pfn_to_online_page(pfn);
1503 if (!page)
1504 continue;
1505
1506 /* Watch for unexpected holes punched in the memmap */
1507 if (!memmap_valid_within(pfn, page, zone))
1508 continue;
1509
1510 if (page_zone(page) != zone)
1511 continue;
1512
1513 mtype = get_pageblock_migratetype(page);
1514
1515 if (mtype < MIGRATE_TYPES)
1516 count[mtype]++;
1517 }
1518
1519 /* Print counts */
1520 seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
1521 for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
1522 seq_printf(m, "%12lu ", count[mtype]);
1523 seq_putc(m, '\n');
1524}
1525
1526/* Print out the number of pageblocks for each migratetype */
1527static int pagetypeinfo_showblockcount(struct seq_file *m, void *arg)
1528{
1529 int mtype;
1530 pg_data_t *pgdat = (pg_data_t *)arg;
1531
1532 seq_printf(m, "\n%-23s", "Number of blocks type ");
1533 for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
1534 seq_printf(m, "%12s ", migratetype_names[mtype]);
1535 seq_putc(m, '\n');
1536 walk_zones_in_node(m, pgdat, true, false,
1537 pagetypeinfo_showblockcount_print);
1538
1539 return 0;
1540}
1541
1542/*
1543 * Print out the number of pageblocks for each migratetype that contain pages
1544 * of other types. This gives an indication of how well fallbacks are being
1545 * contained by rmqueue_fallback(). It requires information from PAGE_OWNER
1546 * to determine what is going on
1547 */
1548static void pagetypeinfo_showmixedcount(struct seq_file *m, pg_data_t *pgdat)
1549{
1550#ifdef CONFIG_PAGE_OWNER
1551 int mtype;
1552
1553 if (!static_branch_unlikely(&page_owner_inited))
1554 return;
1555
1556 drain_all_pages(NULL);
1557
1558 seq_printf(m, "\n%-23s", "Number of mixed blocks ");
1559 for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
1560 seq_printf(m, "%12s ", migratetype_names[mtype]);
1561 seq_putc(m, '\n');
1562
1563 walk_zones_in_node(m, pgdat, true, true,
1564 pagetypeinfo_showmixedcount_print);
1565#endif /* CONFIG_PAGE_OWNER */
1566}
1567
1568/*
1569 * This prints out statistics in relation to grouping pages by mobility.
1570 * It is expensive to collect so do not constantly read the file.
1571 */
1572static int pagetypeinfo_show(struct seq_file *m, void *arg)
1573{
1574 pg_data_t *pgdat = (pg_data_t *)arg;
1575
1576 /* check memoryless node */
1577 if (!node_state(pgdat->node_id, N_MEMORY))
1578 return 0;
1579
1580 seq_printf(m, "Page block order: %d\n", pageblock_order);
1581 seq_printf(m, "Pages per block: %lu\n", pageblock_nr_pages);
1582 seq_putc(m, '\n');
1583 pagetypeinfo_showfree(m, pgdat);
1584 pagetypeinfo_showblockcount(m, pgdat);
1585 pagetypeinfo_showmixedcount(m, pgdat);
1586
1587 return 0;
1588}
1589
1590static const struct seq_operations fragmentation_op = {
1591 .start = frag_start,
1592 .next = frag_next,
1593 .stop = frag_stop,
1594 .show = frag_show,
1595};
1596
1597static const struct seq_operations pagetypeinfo_op = {
1598 .start = frag_start,
1599 .next = frag_next,
1600 .stop = frag_stop,
1601 .show = pagetypeinfo_show,
1602};
1603
1604static bool is_zone_first_populated(pg_data_t *pgdat, struct zone *zone)
1605{
1606 int zid;
1607
1608 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
1609 struct zone *compare = &pgdat->node_zones[zid];
1610
1611 if (populated_zone(compare))
1612 return zone == compare;
1613 }
1614
1615 return false;
1616}
1617
1618static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
1619 struct zone *zone)
1620{
1621 int i;
1622 seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name);
1623 if (is_zone_first_populated(pgdat, zone)) {
1624 seq_printf(m, "\n per-node stats");
1625 for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
1626 seq_printf(m, "\n %-12s %lu", node_stat_name(i),
1627 node_page_state_pages(pgdat, i));
1628 }
1629 }
1630 seq_printf(m,
1631 "\n pages free %lu"
1632 "\n min %lu"
1633 "\n low %lu"
1634 "\n high %lu"
1635 "\n spanned %lu"
1636 "\n present %lu"
1637 "\n managed %lu",
1638 zone_page_state(zone, NR_FREE_PAGES),
1639 min_wmark_pages(zone),
1640 low_wmark_pages(zone),
1641 high_wmark_pages(zone),
1642 zone->spanned_pages,
1643 zone->present_pages,
1644 zone_managed_pages(zone));
1645
1646 seq_printf(m,
1647 "\n protection: (%ld",
1648 zone->lowmem_reserve[0]);
1649 for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++)
1650 seq_printf(m, ", %ld", zone->lowmem_reserve[i]);
1651 seq_putc(m, ')');
1652
1653 /* If unpopulated, no other information is useful */
1654 if (!populated_zone(zone)) {
1655 seq_putc(m, '\n');
1656 return;
1657 }
1658
1659 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
1660 seq_printf(m, "\n %-12s %lu", zone_stat_name(i),
1661 zone_page_state(zone, i));
1662
1663#ifdef CONFIG_NUMA
1664 for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
1665 seq_printf(m, "\n %-12s %lu", numa_stat_name(i),
1666 zone_numa_state_snapshot(zone, i));
1667#endif
1668
1669 seq_printf(m, "\n pagesets");
1670 for_each_online_cpu(i) {
1671 struct per_cpu_pageset *pageset;
1672
1673 pageset = per_cpu_ptr(zone->pageset, i);
1674 seq_printf(m,
1675 "\n cpu: %i"
1676 "\n count: %i"
1677 "\n high: %i"
1678 "\n batch: %i",
1679 i,
1680 pageset->pcp.count,
1681 pageset->pcp.high,
1682 pageset->pcp.batch);
1683#ifdef CONFIG_SMP
1684 seq_printf(m, "\n vm stats threshold: %d",
1685 pageset->stat_threshold);
1686#endif
1687 }
1688 seq_printf(m,
1689 "\n node_unreclaimable: %u"
1690 "\n start_pfn: %lu",
1691 pgdat->kswapd_failures >= MAX_RECLAIM_RETRIES,
1692 zone->zone_start_pfn);
1693 seq_putc(m, '\n');
1694}
1695
1696/*
1697 * Output information about zones in @pgdat. All zones are printed regardless
1698 * of whether they are populated or not: lowmem_reserve_ratio operates on the
1699 * set of all zones and userspace would not be aware of such zones if they are
1700 * suppressed here (zoneinfo displays the effect of lowmem_reserve_ratio).
1701 */
1702static int zoneinfo_show(struct seq_file *m, void *arg)
1703{
1704 pg_data_t *pgdat = (pg_data_t *)arg;
1705 walk_zones_in_node(m, pgdat, false, false, zoneinfo_show_print);
1706 return 0;
1707}
1708
1709static const struct seq_operations zoneinfo_op = {
1710 .start = frag_start, /* iterate over all zones. The same as in
1711 * fragmentation. */
1712 .next = frag_next,
1713 .stop = frag_stop,
1714 .show = zoneinfo_show,
1715};
1716
1717#define NR_VMSTAT_ITEMS (NR_VM_ZONE_STAT_ITEMS + \
1718 NR_VM_NUMA_STAT_ITEMS + \
1719 NR_VM_NODE_STAT_ITEMS + \
1720 NR_VM_WRITEBACK_STAT_ITEMS + \
1721 (IS_ENABLED(CONFIG_VM_EVENT_COUNTERS) ? \
1722 NR_VM_EVENT_ITEMS : 0))
1723
1724static void *vmstat_start(struct seq_file *m, loff_t *pos)
1725{
1726 unsigned long *v;
1727 int i;
1728
1729 if (*pos >= NR_VMSTAT_ITEMS)
1730 return NULL;
1731
1732 BUILD_BUG_ON(ARRAY_SIZE(vmstat_text) < NR_VMSTAT_ITEMS);
1733 v = kmalloc_array(NR_VMSTAT_ITEMS, sizeof(unsigned long), GFP_KERNEL);
1734 m->private = v;
1735 if (!v)
1736 return ERR_PTR(-ENOMEM);
1737 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
1738 v[i] = global_zone_page_state(i);
1739 v += NR_VM_ZONE_STAT_ITEMS;
1740
1741#ifdef CONFIG_NUMA
1742 for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++)
1743 v[i] = global_numa_state(i);
1744 v += NR_VM_NUMA_STAT_ITEMS;
1745#endif
1746
1747 for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
1748 v[i] = global_node_page_state_pages(i);
1749 v += NR_VM_NODE_STAT_ITEMS;
1750
1751 global_dirty_limits(v + NR_DIRTY_BG_THRESHOLD,
1752 v + NR_DIRTY_THRESHOLD);
1753 v += NR_VM_WRITEBACK_STAT_ITEMS;
1754
1755#ifdef CONFIG_VM_EVENT_COUNTERS
1756 all_vm_events(v);
1757 v[PGPGIN] /= 2; /* sectors -> kbytes */
1758 v[PGPGOUT] /= 2;
1759#endif
1760 return (unsigned long *)m->private + *pos;
1761}
1762
1763static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)
1764{
1765 (*pos)++;
1766 if (*pos >= NR_VMSTAT_ITEMS)
1767 return NULL;
1768 return (unsigned long *)m->private + *pos;
1769}
1770
1771static int vmstat_show(struct seq_file *m, void *arg)
1772{
1773 unsigned long *l = arg;
1774 unsigned long off = l - (unsigned long *)m->private;
1775
1776 seq_puts(m, vmstat_text[off]);
1777 seq_put_decimal_ull(m, " ", *l);
1778 seq_putc(m, '\n');
1779
1780 if (off == NR_VMSTAT_ITEMS - 1) {
1781 /*
1782 * We've come to the end - add any deprecated counters to avoid
1783 * breaking userspace which might depend on them being present.
1784 */
1785 seq_puts(m, "nr_unstable 0\n");
1786 }
1787 return 0;
1788}
1789
1790static void vmstat_stop(struct seq_file *m, void *arg)
1791{
1792 kfree(m->private);
1793 m->private = NULL;
1794}
1795
1796static const struct seq_operations vmstat_op = {
1797 .start = vmstat_start,
1798 .next = vmstat_next,
1799 .stop = vmstat_stop,
1800 .show = vmstat_show,
1801};
1802#endif /* CONFIG_PROC_FS */
1803
1804#ifdef CONFIG_SMP
1805static DEFINE_PER_CPU(struct delayed_work, vmstat_work);
1806int sysctl_stat_interval __read_mostly = HZ;
1807
1808#ifdef CONFIG_PROC_FS
1809static void refresh_vm_stats(struct work_struct *work)
1810{
1811 refresh_cpu_vm_stats(true);
1812}
1813
1814int vmstat_refresh(struct ctl_table *table, int write,
1815 void *buffer, size_t *lenp, loff_t *ppos)
1816{
1817 long val;
1818 int err;
1819 int i;
1820
1821 /*
1822 * The regular update, every sysctl_stat_interval, may come later
1823 * than expected: leaving a significant amount in per_cpu buckets.
1824 * This is particularly misleading when checking a quantity of HUGE
1825 * pages, immediately after running a test. /proc/sys/vm/stat_refresh,
1826 * which can equally be echo'ed to or cat'ted from (by root),
1827 * can be used to update the stats just before reading them.
1828 *
1829 * Oh, and since global_zone_page_state() etc. are so careful to hide
1830 * transiently negative values, report an error here if any of
1831 * the stats is negative, so we know to go looking for imbalance.
1832 */
1833 err = schedule_on_each_cpu(refresh_vm_stats);
1834 if (err)
1835 return err;
1836 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
1837 val = atomic_long_read(&vm_zone_stat[i]);
1838 if (val < 0) {
1839 pr_warn("%s: %s %ld\n",
1840 __func__, zone_stat_name(i), val);
1841 err = -EINVAL;
1842 }
1843 }
1844#ifdef CONFIG_NUMA
1845 for (i = 0; i < NR_VM_NUMA_STAT_ITEMS; i++) {
1846 val = atomic_long_read(&vm_numa_stat[i]);
1847 if (val < 0) {
1848 pr_warn("%s: %s %ld\n",
1849 __func__, numa_stat_name(i), val);
1850 err = -EINVAL;
1851 }
1852 }
1853#endif
1854 if (err)
1855 return err;
1856 if (write)
1857 *ppos += *lenp;
1858 else
1859 *lenp = 0;
1860 return 0;
1861}
1862#endif /* CONFIG_PROC_FS */
1863
1864static void vmstat_update(struct work_struct *w)
1865{
1866 if (refresh_cpu_vm_stats(true)) {
1867 /*
1868 * Counters were updated so we expect more updates
1869 * to occur in the future. Keep on running the
1870 * update worker thread.
1871 */
1872 queue_delayed_work_on(smp_processor_id(), mm_percpu_wq,
1873 this_cpu_ptr(&vmstat_work),
1874 round_jiffies_relative(sysctl_stat_interval));
1875 }
1876}
1877
1878/*
1879 * Switch off vmstat processing and then fold all the remaining differentials
1880 * until the diffs stay at zero. The function is used by NOHZ and can only be
1881 * invoked when tick processing is not active.
1882 */
1883/*
1884 * Check if the diffs for a certain cpu indicate that
1885 * an update is needed.
1886 */
1887static bool need_update(int cpu)
1888{
1889 struct zone *zone;
1890
1891 for_each_populated_zone(zone) {
1892 struct per_cpu_pageset *p = per_cpu_ptr(zone->pageset, cpu);
1893
1894 BUILD_BUG_ON(sizeof(p->vm_stat_diff[0]) != 1);
1895#ifdef CONFIG_NUMA
1896 BUILD_BUG_ON(sizeof(p->vm_numa_stat_diff[0]) != 2);
1897#endif
1898
1899 /*
1900 * The fast way of checking if there are any vmstat diffs.
1901 */
1902 if (memchr_inv(p->vm_stat_diff, 0, NR_VM_ZONE_STAT_ITEMS *
1903 sizeof(p->vm_stat_diff[0])))
1904 return true;
1905#ifdef CONFIG_NUMA
1906 if (memchr_inv(p->vm_numa_stat_diff, 0, NR_VM_NUMA_STAT_ITEMS *
1907 sizeof(p->vm_numa_stat_diff[0])))
1908 return true;
1909#endif
1910 }
1911 return false;
1912}
1913
1914/*
1915 * Switch off vmstat processing and then fold all the remaining differentials
1916 * until the diffs stay at zero. The function is used by NOHZ and can only be
1917 * invoked when tick processing is not active.
1918 */
1919void quiet_vmstat(void)
1920{
1921 if (system_state != SYSTEM_RUNNING)
1922 return;
1923
1924 if (!delayed_work_pending(this_cpu_ptr(&vmstat_work)))
1925 return;
1926
1927 if (!need_update(smp_processor_id()))
1928 return;
1929
1930 /*
1931 * Just refresh counters and do not care about the pending delayed
1932 * vmstat_update. It doesn't fire that often to matter and canceling
1933 * it would be too expensive from this path.
1934 * vmstat_shepherd will take care about that for us.
1935 */
1936 refresh_cpu_vm_stats(false);
1937}
1938
1939/*
1940 * Shepherd worker thread that checks the
1941 * differentials of processors that have their worker
1942 * threads for vm statistics updates disabled because of
1943 * inactivity.
1944 */
1945static void vmstat_shepherd(struct work_struct *w);
1946
1947static DECLARE_DEFERRABLE_WORK(shepherd, vmstat_shepherd);
1948
1949static void vmstat_shepherd(struct work_struct *w)
1950{
1951 int cpu;
1952
1953 get_online_cpus();
1954 /* Check processors whose vmstat worker threads have been disabled */
1955 for_each_online_cpu(cpu) {
1956 struct delayed_work *dw = &per_cpu(vmstat_work, cpu);
1957
1958 if (!delayed_work_pending(dw) && need_update(cpu))
1959 queue_delayed_work_on(cpu, mm_percpu_wq, dw, 0);
1960 }
1961 put_online_cpus();
1962
1963 schedule_delayed_work(&shepherd,
1964 round_jiffies_relative(sysctl_stat_interval));
1965}
1966
1967static void __init start_shepherd_timer(void)
1968{
1969 int cpu;
1970
1971 for_each_possible_cpu(cpu)
1972 INIT_DEFERRABLE_WORK(per_cpu_ptr(&vmstat_work, cpu),
1973 vmstat_update);
1974
1975 schedule_delayed_work(&shepherd,
1976 round_jiffies_relative(sysctl_stat_interval));
1977}
1978
1979static void __init init_cpu_node_state(void)
1980{
1981 int node;
1982
1983 for_each_online_node(node) {
1984 if (cpumask_weight(cpumask_of_node(node)) > 0)
1985 node_set_state(node, N_CPU);
1986 }
1987}
1988
1989static int vmstat_cpu_online(unsigned int cpu)
1990{
1991 refresh_zone_stat_thresholds();
1992 node_set_state(cpu_to_node(cpu), N_CPU);
1993 return 0;
1994}
1995
1996static int vmstat_cpu_down_prep(unsigned int cpu)
1997{
1998 cancel_delayed_work_sync(&per_cpu(vmstat_work, cpu));
1999 return 0;
2000}
2001
2002static int vmstat_cpu_dead(unsigned int cpu)
2003{
2004 const struct cpumask *node_cpus;
2005 int node;
2006
2007 node = cpu_to_node(cpu);
2008
2009 refresh_zone_stat_thresholds();
2010 node_cpus = cpumask_of_node(node);
2011 if (cpumask_weight(node_cpus) > 0)
2012 return 0;
2013
2014 node_clear_state(node, N_CPU);
2015 return 0;
2016}
2017
2018#endif
2019
2020struct workqueue_struct *mm_percpu_wq;
2021
2022void __init init_mm_internals(void)
2023{
2024 int ret __maybe_unused;
2025
2026 mm_percpu_wq = alloc_workqueue("mm_percpu_wq", WQ_MEM_RECLAIM, 0);
2027
2028#ifdef CONFIG_SMP
2029 ret = cpuhp_setup_state_nocalls(CPUHP_MM_VMSTAT_DEAD, "mm/vmstat:dead",
2030 NULL, vmstat_cpu_dead);
2031 if (ret < 0)
2032 pr_err("vmstat: failed to register 'dead' hotplug state\n");
2033
2034 ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "mm/vmstat:online",
2035 vmstat_cpu_online,
2036 vmstat_cpu_down_prep);
2037 if (ret < 0)
2038 pr_err("vmstat: failed to register 'online' hotplug state\n");
2039
2040 get_online_cpus();
2041 init_cpu_node_state();
2042 put_online_cpus();
2043
2044 start_shepherd_timer();
2045#endif
2046#ifdef CONFIG_PROC_FS
2047 proc_create_seq("buddyinfo", 0444, NULL, &fragmentation_op);
2048 proc_create_seq("pagetypeinfo", 0400, NULL, &pagetypeinfo_op);
2049 proc_create_seq("vmstat", 0444, NULL, &vmstat_op);
2050 proc_create_seq("zoneinfo", 0444, NULL, &zoneinfo_op);
2051#endif
2052}
2053
2054#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)
2055
2056/*
2057 * Return an index indicating how much of the available free memory is
2058 * unusable for an allocation of the requested size.
2059 */
2060static int unusable_free_index(unsigned int order,
2061 struct contig_page_info *info)
2062{
2063 /* No free memory is interpreted as all free memory is unusable */
2064 if (info->free_pages == 0)
2065 return 1000;
2066
2067 /*
2068 * Index should be a value between 0 and 1. Return a value to 3
2069 * decimal places.
2070 *
2071 * 0 => no fragmentation
2072 * 1 => high fragmentation
2073 */
2074 return div_u64((info->free_pages - (info->free_blocks_suitable << order)) * 1000ULL, info->free_pages);
2075
2076}
2077
2078static void unusable_show_print(struct seq_file *m,
2079 pg_data_t *pgdat, struct zone *zone)
2080{
2081 unsigned int order;
2082 int index;
2083 struct contig_page_info info;
2084
2085 seq_printf(m, "Node %d, zone %8s ",
2086 pgdat->node_id,
2087 zone->name);
2088 for (order = 0; order < MAX_ORDER; ++order) {
2089 fill_contig_page_info(zone, order, &info);
2090 index = unusable_free_index(order, &info);
2091 seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
2092 }
2093
2094 seq_putc(m, '\n');
2095}
2096
2097/*
2098 * Display unusable free space index
2099 *
2100 * The unusable free space index measures how much of the available free
2101 * memory cannot be used to satisfy an allocation of a given size and is a
2102 * value between 0 and 1. The higher the value, the more of free memory is
2103 * unusable and by implication, the worse the external fragmentation is. This
2104 * can be expressed as a percentage by multiplying by 100.
2105 */
2106static int unusable_show(struct seq_file *m, void *arg)
2107{
2108 pg_data_t *pgdat = (pg_data_t *)arg;
2109
2110 /* check memoryless node */
2111 if (!node_state(pgdat->node_id, N_MEMORY))
2112 return 0;
2113
2114 walk_zones_in_node(m, pgdat, true, false, unusable_show_print);
2115
2116 return 0;
2117}
2118
2119static const struct seq_operations unusable_sops = {
2120 .start = frag_start,
2121 .next = frag_next,
2122 .stop = frag_stop,
2123 .show = unusable_show,
2124};
2125
2126DEFINE_SEQ_ATTRIBUTE(unusable);
2127
2128static void extfrag_show_print(struct seq_file *m,
2129 pg_data_t *pgdat, struct zone *zone)
2130{
2131 unsigned int order;
2132 int index;
2133
2134 /* Alloc on stack as interrupts are disabled for zone walk */
2135 struct contig_page_info info;
2136
2137 seq_printf(m, "Node %d, zone %8s ",
2138 pgdat->node_id,
2139 zone->name);
2140 for (order = 0; order < MAX_ORDER; ++order) {
2141 fill_contig_page_info(zone, order, &info);
2142 index = __fragmentation_index(order, &info);
2143 seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
2144 }
2145
2146 seq_putc(m, '\n');
2147}
2148
2149/*
2150 * Display fragmentation index for orders that allocations would fail for
2151 */
2152static int extfrag_show(struct seq_file *m, void *arg)
2153{
2154 pg_data_t *pgdat = (pg_data_t *)arg;
2155
2156 walk_zones_in_node(m, pgdat, true, false, extfrag_show_print);
2157
2158 return 0;
2159}
2160
2161static const struct seq_operations extfrag_sops = {
2162 .start = frag_start,
2163 .next = frag_next,
2164 .stop = frag_stop,
2165 .show = extfrag_show,
2166};
2167
2168DEFINE_SEQ_ATTRIBUTE(extfrag);
2169
2170static int __init extfrag_debug_init(void)
2171{
2172 struct dentry *extfrag_debug_root;
2173
2174 extfrag_debug_root = debugfs_create_dir("extfrag", NULL);
2175
2176 debugfs_create_file("unusable_index", 0444, extfrag_debug_root, NULL,
2177 &unusable_fops);
2178
2179 debugfs_create_file("extfrag_index", 0444, extfrag_debug_root, NULL,
2180 &extfrag_fops);
2181
2182 return 0;
2183}
2184
2185module_init(extfrag_debug_init);
2186#endif
1/*
2 * linux/mm/vmstat.c
3 *
4 * Manages VM statistics
5 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
6 *
7 * zoned VM statistics
8 * Copyright (C) 2006 Silicon Graphics, Inc.,
9 * Christoph Lameter <christoph@lameter.com>
10 * Copyright (C) 2008-2014 Christoph Lameter
11 */
12#include <linux/fs.h>
13#include <linux/mm.h>
14#include <linux/err.h>
15#include <linux/module.h>
16#include <linux/slab.h>
17#include <linux/cpu.h>
18#include <linux/cpumask.h>
19#include <linux/vmstat.h>
20#include <linux/proc_fs.h>
21#include <linux/seq_file.h>
22#include <linux/debugfs.h>
23#include <linux/sched.h>
24#include <linux/math64.h>
25#include <linux/writeback.h>
26#include <linux/compaction.h>
27#include <linux/mm_inline.h>
28#include <linux/page_ext.h>
29#include <linux/page_owner.h>
30
31#include "internal.h"
32
33#ifdef CONFIG_VM_EVENT_COUNTERS
34DEFINE_PER_CPU(struct vm_event_state, vm_event_states) = {{0}};
35EXPORT_PER_CPU_SYMBOL(vm_event_states);
36
37static void sum_vm_events(unsigned long *ret)
38{
39 int cpu;
40 int i;
41
42 memset(ret, 0, NR_VM_EVENT_ITEMS * sizeof(unsigned long));
43
44 for_each_online_cpu(cpu) {
45 struct vm_event_state *this = &per_cpu(vm_event_states, cpu);
46
47 for (i = 0; i < NR_VM_EVENT_ITEMS; i++)
48 ret[i] += this->event[i];
49 }
50}
51
52/*
53 * Accumulate the vm event counters across all CPUs.
54 * The result is unavoidably approximate - it can change
55 * during and after execution of this function.
56*/
57void all_vm_events(unsigned long *ret)
58{
59 get_online_cpus();
60 sum_vm_events(ret);
61 put_online_cpus();
62}
63EXPORT_SYMBOL_GPL(all_vm_events);
64
65/*
66 * Fold the foreign cpu events into our own.
67 *
68 * This is adding to the events on one processor
69 * but keeps the global counts constant.
70 */
71void vm_events_fold_cpu(int cpu)
72{
73 struct vm_event_state *fold_state = &per_cpu(vm_event_states, cpu);
74 int i;
75
76 for (i = 0; i < NR_VM_EVENT_ITEMS; i++) {
77 count_vm_events(i, fold_state->event[i]);
78 fold_state->event[i] = 0;
79 }
80}
81
82#endif /* CONFIG_VM_EVENT_COUNTERS */
83
84/*
85 * Manage combined zone based / global counters
86 *
87 * vm_stat contains the global counters
88 */
89atomic_long_t vm_zone_stat[NR_VM_ZONE_STAT_ITEMS] __cacheline_aligned_in_smp;
90atomic_long_t vm_node_stat[NR_VM_NODE_STAT_ITEMS] __cacheline_aligned_in_smp;
91EXPORT_SYMBOL(vm_zone_stat);
92EXPORT_SYMBOL(vm_node_stat);
93
94#ifdef CONFIG_SMP
95
96int calculate_pressure_threshold(struct zone *zone)
97{
98 int threshold;
99 int watermark_distance;
100
101 /*
102 * As vmstats are not up to date, there is drift between the estimated
103 * and real values. For high thresholds and a high number of CPUs, it
104 * is possible for the min watermark to be breached while the estimated
105 * value looks fine. The pressure threshold is a reduced value such
106 * that even the maximum amount of drift will not accidentally breach
107 * the min watermark
108 */
109 watermark_distance = low_wmark_pages(zone) - min_wmark_pages(zone);
110 threshold = max(1, (int)(watermark_distance / num_online_cpus()));
111
112 /*
113 * Maximum threshold is 125
114 */
115 threshold = min(125, threshold);
116
117 return threshold;
118}
119
120int calculate_normal_threshold(struct zone *zone)
121{
122 int threshold;
123 int mem; /* memory in 128 MB units */
124
125 /*
126 * The threshold scales with the number of processors and the amount
127 * of memory per zone. More memory means that we can defer updates for
128 * longer, more processors could lead to more contention.
129 * fls() is used to have a cheap way of logarithmic scaling.
130 *
131 * Some sample thresholds:
132 *
133 * Threshold Processors (fls) Zonesize fls(mem+1)
134 * ------------------------------------------------------------------
135 * 8 1 1 0.9-1 GB 4
136 * 16 2 2 0.9-1 GB 4
137 * 20 2 2 1-2 GB 5
138 * 24 2 2 2-4 GB 6
139 * 28 2 2 4-8 GB 7
140 * 32 2 2 8-16 GB 8
141 * 4 2 2 <128M 1
142 * 30 4 3 2-4 GB 5
143 * 48 4 3 8-16 GB 8
144 * 32 8 4 1-2 GB 4
145 * 32 8 4 0.9-1GB 4
146 * 10 16 5 <128M 1
147 * 40 16 5 900M 4
148 * 70 64 7 2-4 GB 5
149 * 84 64 7 4-8 GB 6
150 * 108 512 9 4-8 GB 6
151 * 125 1024 10 8-16 GB 8
152 * 125 1024 10 16-32 GB 9
153 */
154
155 mem = zone->managed_pages >> (27 - PAGE_SHIFT);
156
157 threshold = 2 * fls(num_online_cpus()) * (1 + fls(mem));
158
159 /*
160 * Maximum threshold is 125
161 */
162 threshold = min(125, threshold);
163
164 return threshold;
165}
166
167/*
168 * Refresh the thresholds for each zone.
169 */
170void refresh_zone_stat_thresholds(void)
171{
172 struct pglist_data *pgdat;
173 struct zone *zone;
174 int cpu;
175 int threshold;
176
177 /* Zero current pgdat thresholds */
178 for_each_online_pgdat(pgdat) {
179 for_each_online_cpu(cpu) {
180 per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold = 0;
181 }
182 }
183
184 for_each_populated_zone(zone) {
185 struct pglist_data *pgdat = zone->zone_pgdat;
186 unsigned long max_drift, tolerate_drift;
187
188 threshold = calculate_normal_threshold(zone);
189
190 for_each_online_cpu(cpu) {
191 int pgdat_threshold;
192
193 per_cpu_ptr(zone->pageset, cpu)->stat_threshold
194 = threshold;
195
196 /* Base nodestat threshold on the largest populated zone. */
197 pgdat_threshold = per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold;
198 per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->stat_threshold
199 = max(threshold, pgdat_threshold);
200 }
201
202 /*
203 * Only set percpu_drift_mark if there is a danger that
204 * NR_FREE_PAGES reports the low watermark is ok when in fact
205 * the min watermark could be breached by an allocation
206 */
207 tolerate_drift = low_wmark_pages(zone) - min_wmark_pages(zone);
208 max_drift = num_online_cpus() * threshold;
209 if (max_drift > tolerate_drift)
210 zone->percpu_drift_mark = high_wmark_pages(zone) +
211 max_drift;
212 }
213}
214
215void set_pgdat_percpu_threshold(pg_data_t *pgdat,
216 int (*calculate_pressure)(struct zone *))
217{
218 struct zone *zone;
219 int cpu;
220 int threshold;
221 int i;
222
223 for (i = 0; i < pgdat->nr_zones; i++) {
224 zone = &pgdat->node_zones[i];
225 if (!zone->percpu_drift_mark)
226 continue;
227
228 threshold = (*calculate_pressure)(zone);
229 for_each_online_cpu(cpu)
230 per_cpu_ptr(zone->pageset, cpu)->stat_threshold
231 = threshold;
232 }
233}
234
235/*
236 * For use when we know that interrupts are disabled,
237 * or when we know that preemption is disabled and that
238 * particular counter cannot be updated from interrupt context.
239 */
240void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
241 long delta)
242{
243 struct per_cpu_pageset __percpu *pcp = zone->pageset;
244 s8 __percpu *p = pcp->vm_stat_diff + item;
245 long x;
246 long t;
247
248 x = delta + __this_cpu_read(*p);
249
250 t = __this_cpu_read(pcp->stat_threshold);
251
252 if (unlikely(x > t || x < -t)) {
253 zone_page_state_add(x, zone, item);
254 x = 0;
255 }
256 __this_cpu_write(*p, x);
257}
258EXPORT_SYMBOL(__mod_zone_page_state);
259
260void __mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
261 long delta)
262{
263 struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
264 s8 __percpu *p = pcp->vm_node_stat_diff + item;
265 long x;
266 long t;
267
268 x = delta + __this_cpu_read(*p);
269
270 t = __this_cpu_read(pcp->stat_threshold);
271
272 if (unlikely(x > t || x < -t)) {
273 node_page_state_add(x, pgdat, item);
274 x = 0;
275 }
276 __this_cpu_write(*p, x);
277}
278EXPORT_SYMBOL(__mod_node_page_state);
279
280/*
281 * Optimized increment and decrement functions.
282 *
283 * These are only for a single page and therefore can take a struct page *
284 * argument instead of struct zone *. This allows the inclusion of the code
285 * generated for page_zone(page) into the optimized functions.
286 *
287 * No overflow check is necessary and therefore the differential can be
288 * incremented or decremented in place which may allow the compilers to
289 * generate better code.
290 * The increment or decrement is known and therefore one boundary check can
291 * be omitted.
292 *
293 * NOTE: These functions are very performance sensitive. Change only
294 * with care.
295 *
296 * Some processors have inc/dec instructions that are atomic vs an interrupt.
297 * However, the code must first determine the differential location in a zone
298 * based on the processor number and then inc/dec the counter. There is no
299 * guarantee without disabling preemption that the processor will not change
300 * in between and therefore the atomicity vs. interrupt cannot be exploited
301 * in a useful way here.
302 */
303void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
304{
305 struct per_cpu_pageset __percpu *pcp = zone->pageset;
306 s8 __percpu *p = pcp->vm_stat_diff + item;
307 s8 v, t;
308
309 v = __this_cpu_inc_return(*p);
310 t = __this_cpu_read(pcp->stat_threshold);
311 if (unlikely(v > t)) {
312 s8 overstep = t >> 1;
313
314 zone_page_state_add(v + overstep, zone, item);
315 __this_cpu_write(*p, -overstep);
316 }
317}
318
319void __inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
320{
321 struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
322 s8 __percpu *p = pcp->vm_node_stat_diff + item;
323 s8 v, t;
324
325 v = __this_cpu_inc_return(*p);
326 t = __this_cpu_read(pcp->stat_threshold);
327 if (unlikely(v > t)) {
328 s8 overstep = t >> 1;
329
330 node_page_state_add(v + overstep, pgdat, item);
331 __this_cpu_write(*p, -overstep);
332 }
333}
334
335void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
336{
337 __inc_zone_state(page_zone(page), item);
338}
339EXPORT_SYMBOL(__inc_zone_page_state);
340
341void __inc_node_page_state(struct page *page, enum node_stat_item item)
342{
343 __inc_node_state(page_pgdat(page), item);
344}
345EXPORT_SYMBOL(__inc_node_page_state);
346
347void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
348{
349 struct per_cpu_pageset __percpu *pcp = zone->pageset;
350 s8 __percpu *p = pcp->vm_stat_diff + item;
351 s8 v, t;
352
353 v = __this_cpu_dec_return(*p);
354 t = __this_cpu_read(pcp->stat_threshold);
355 if (unlikely(v < - t)) {
356 s8 overstep = t >> 1;
357
358 zone_page_state_add(v - overstep, zone, item);
359 __this_cpu_write(*p, overstep);
360 }
361}
362
363void __dec_node_state(struct pglist_data *pgdat, enum node_stat_item item)
364{
365 struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
366 s8 __percpu *p = pcp->vm_node_stat_diff + item;
367 s8 v, t;
368
369 v = __this_cpu_dec_return(*p);
370 t = __this_cpu_read(pcp->stat_threshold);
371 if (unlikely(v < - t)) {
372 s8 overstep = t >> 1;
373
374 node_page_state_add(v - overstep, pgdat, item);
375 __this_cpu_write(*p, overstep);
376 }
377}
378
379void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
380{
381 __dec_zone_state(page_zone(page), item);
382}
383EXPORT_SYMBOL(__dec_zone_page_state);
384
385void __dec_node_page_state(struct page *page, enum node_stat_item item)
386{
387 __dec_node_state(page_pgdat(page), item);
388}
389EXPORT_SYMBOL(__dec_node_page_state);
390
391#ifdef CONFIG_HAVE_CMPXCHG_LOCAL
392/*
393 * If we have cmpxchg_local support then we do not need to incur the overhead
394 * that comes with local_irq_save/restore if we use this_cpu_cmpxchg.
395 *
396 * mod_state() modifies the zone counter state through atomic per cpu
397 * operations.
398 *
399 * Overstep mode specifies how overstep should handled:
400 * 0 No overstepping
401 * 1 Overstepping half of threshold
402 * -1 Overstepping minus half of threshold
403*/
404static inline void mod_zone_state(struct zone *zone,
405 enum zone_stat_item item, long delta, int overstep_mode)
406{
407 struct per_cpu_pageset __percpu *pcp = zone->pageset;
408 s8 __percpu *p = pcp->vm_stat_diff + item;
409 long o, n, t, z;
410
411 do {
412 z = 0; /* overflow to zone counters */
413
414 /*
415 * The fetching of the stat_threshold is racy. We may apply
416 * a counter threshold to the wrong the cpu if we get
417 * rescheduled while executing here. However, the next
418 * counter update will apply the threshold again and
419 * therefore bring the counter under the threshold again.
420 *
421 * Most of the time the thresholds are the same anyways
422 * for all cpus in a zone.
423 */
424 t = this_cpu_read(pcp->stat_threshold);
425
426 o = this_cpu_read(*p);
427 n = delta + o;
428
429 if (n > t || n < -t) {
430 int os = overstep_mode * (t >> 1) ;
431
432 /* Overflow must be added to zone counters */
433 z = n + os;
434 n = -os;
435 }
436 } while (this_cpu_cmpxchg(*p, o, n) != o);
437
438 if (z)
439 zone_page_state_add(z, zone, item);
440}
441
442void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
443 long delta)
444{
445 mod_zone_state(zone, item, delta, 0);
446}
447EXPORT_SYMBOL(mod_zone_page_state);
448
449void inc_zone_page_state(struct page *page, enum zone_stat_item item)
450{
451 mod_zone_state(page_zone(page), item, 1, 1);
452}
453EXPORT_SYMBOL(inc_zone_page_state);
454
455void dec_zone_page_state(struct page *page, enum zone_stat_item item)
456{
457 mod_zone_state(page_zone(page), item, -1, -1);
458}
459EXPORT_SYMBOL(dec_zone_page_state);
460
461static inline void mod_node_state(struct pglist_data *pgdat,
462 enum node_stat_item item, int delta, int overstep_mode)
463{
464 struct per_cpu_nodestat __percpu *pcp = pgdat->per_cpu_nodestats;
465 s8 __percpu *p = pcp->vm_node_stat_diff + item;
466 long o, n, t, z;
467
468 do {
469 z = 0; /* overflow to node counters */
470
471 /*
472 * The fetching of the stat_threshold is racy. We may apply
473 * a counter threshold to the wrong the cpu if we get
474 * rescheduled while executing here. However, the next
475 * counter update will apply the threshold again and
476 * therefore bring the counter under the threshold again.
477 *
478 * Most of the time the thresholds are the same anyways
479 * for all cpus in a node.
480 */
481 t = this_cpu_read(pcp->stat_threshold);
482
483 o = this_cpu_read(*p);
484 n = delta + o;
485
486 if (n > t || n < -t) {
487 int os = overstep_mode * (t >> 1) ;
488
489 /* Overflow must be added to node counters */
490 z = n + os;
491 n = -os;
492 }
493 } while (this_cpu_cmpxchg(*p, o, n) != o);
494
495 if (z)
496 node_page_state_add(z, pgdat, item);
497}
498
499void mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
500 long delta)
501{
502 mod_node_state(pgdat, item, delta, 0);
503}
504EXPORT_SYMBOL(mod_node_page_state);
505
506void inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
507{
508 mod_node_state(pgdat, item, 1, 1);
509}
510
511void inc_node_page_state(struct page *page, enum node_stat_item item)
512{
513 mod_node_state(page_pgdat(page), item, 1, 1);
514}
515EXPORT_SYMBOL(inc_node_page_state);
516
517void dec_node_page_state(struct page *page, enum node_stat_item item)
518{
519 mod_node_state(page_pgdat(page), item, -1, -1);
520}
521EXPORT_SYMBOL(dec_node_page_state);
522#else
523/*
524 * Use interrupt disable to serialize counter updates
525 */
526void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
527 long delta)
528{
529 unsigned long flags;
530
531 local_irq_save(flags);
532 __mod_zone_page_state(zone, item, delta);
533 local_irq_restore(flags);
534}
535EXPORT_SYMBOL(mod_zone_page_state);
536
537void inc_zone_page_state(struct page *page, enum zone_stat_item item)
538{
539 unsigned long flags;
540 struct zone *zone;
541
542 zone = page_zone(page);
543 local_irq_save(flags);
544 __inc_zone_state(zone, item);
545 local_irq_restore(flags);
546}
547EXPORT_SYMBOL(inc_zone_page_state);
548
549void dec_zone_page_state(struct page *page, enum zone_stat_item item)
550{
551 unsigned long flags;
552
553 local_irq_save(flags);
554 __dec_zone_page_state(page, item);
555 local_irq_restore(flags);
556}
557EXPORT_SYMBOL(dec_zone_page_state);
558
559void inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
560{
561 unsigned long flags;
562
563 local_irq_save(flags);
564 __inc_node_state(pgdat, item);
565 local_irq_restore(flags);
566}
567EXPORT_SYMBOL(inc_node_state);
568
569void mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
570 long delta)
571{
572 unsigned long flags;
573
574 local_irq_save(flags);
575 __mod_node_page_state(pgdat, item, delta);
576 local_irq_restore(flags);
577}
578EXPORT_SYMBOL(mod_node_page_state);
579
580void inc_node_page_state(struct page *page, enum node_stat_item item)
581{
582 unsigned long flags;
583 struct pglist_data *pgdat;
584
585 pgdat = page_pgdat(page);
586 local_irq_save(flags);
587 __inc_node_state(pgdat, item);
588 local_irq_restore(flags);
589}
590EXPORT_SYMBOL(inc_node_page_state);
591
592void dec_node_page_state(struct page *page, enum node_stat_item item)
593{
594 unsigned long flags;
595
596 local_irq_save(flags);
597 __dec_node_page_state(page, item);
598 local_irq_restore(flags);
599}
600EXPORT_SYMBOL(dec_node_page_state);
601#endif
602
603/*
604 * Fold a differential into the global counters.
605 * Returns the number of counters updated.
606 */
607static int fold_diff(int *zone_diff, int *node_diff)
608{
609 int i;
610 int changes = 0;
611
612 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
613 if (zone_diff[i]) {
614 atomic_long_add(zone_diff[i], &vm_zone_stat[i]);
615 changes++;
616 }
617
618 for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
619 if (node_diff[i]) {
620 atomic_long_add(node_diff[i], &vm_node_stat[i]);
621 changes++;
622 }
623 return changes;
624}
625
626/*
627 * Update the zone counters for the current cpu.
628 *
629 * Note that refresh_cpu_vm_stats strives to only access
630 * node local memory. The per cpu pagesets on remote zones are placed
631 * in the memory local to the processor using that pageset. So the
632 * loop over all zones will access a series of cachelines local to
633 * the processor.
634 *
635 * The call to zone_page_state_add updates the cachelines with the
636 * statistics in the remote zone struct as well as the global cachelines
637 * with the global counters. These could cause remote node cache line
638 * bouncing and will have to be only done when necessary.
639 *
640 * The function returns the number of global counters updated.
641 */
642static int refresh_cpu_vm_stats(bool do_pagesets)
643{
644 struct pglist_data *pgdat;
645 struct zone *zone;
646 int i;
647 int global_zone_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
648 int global_node_diff[NR_VM_NODE_STAT_ITEMS] = { 0, };
649 int changes = 0;
650
651 for_each_populated_zone(zone) {
652 struct per_cpu_pageset __percpu *p = zone->pageset;
653
654 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
655 int v;
656
657 v = this_cpu_xchg(p->vm_stat_diff[i], 0);
658 if (v) {
659
660 atomic_long_add(v, &zone->vm_stat[i]);
661 global_zone_diff[i] += v;
662#ifdef CONFIG_NUMA
663 /* 3 seconds idle till flush */
664 __this_cpu_write(p->expire, 3);
665#endif
666 }
667 }
668#ifdef CONFIG_NUMA
669 if (do_pagesets) {
670 cond_resched();
671 /*
672 * Deal with draining the remote pageset of this
673 * processor
674 *
675 * Check if there are pages remaining in this pageset
676 * if not then there is nothing to expire.
677 */
678 if (!__this_cpu_read(p->expire) ||
679 !__this_cpu_read(p->pcp.count))
680 continue;
681
682 /*
683 * We never drain zones local to this processor.
684 */
685 if (zone_to_nid(zone) == numa_node_id()) {
686 __this_cpu_write(p->expire, 0);
687 continue;
688 }
689
690 if (__this_cpu_dec_return(p->expire))
691 continue;
692
693 if (__this_cpu_read(p->pcp.count)) {
694 drain_zone_pages(zone, this_cpu_ptr(&p->pcp));
695 changes++;
696 }
697 }
698#endif
699 }
700
701 for_each_online_pgdat(pgdat) {
702 struct per_cpu_nodestat __percpu *p = pgdat->per_cpu_nodestats;
703
704 for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
705 int v;
706
707 v = this_cpu_xchg(p->vm_node_stat_diff[i], 0);
708 if (v) {
709 atomic_long_add(v, &pgdat->vm_stat[i]);
710 global_node_diff[i] += v;
711 }
712 }
713 }
714
715 changes += fold_diff(global_zone_diff, global_node_diff);
716 return changes;
717}
718
719/*
720 * Fold the data for an offline cpu into the global array.
721 * There cannot be any access by the offline cpu and therefore
722 * synchronization is simplified.
723 */
724void cpu_vm_stats_fold(int cpu)
725{
726 struct pglist_data *pgdat;
727 struct zone *zone;
728 int i;
729 int global_zone_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
730 int global_node_diff[NR_VM_NODE_STAT_ITEMS] = { 0, };
731
732 for_each_populated_zone(zone) {
733 struct per_cpu_pageset *p;
734
735 p = per_cpu_ptr(zone->pageset, cpu);
736
737 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
738 if (p->vm_stat_diff[i]) {
739 int v;
740
741 v = p->vm_stat_diff[i];
742 p->vm_stat_diff[i] = 0;
743 atomic_long_add(v, &zone->vm_stat[i]);
744 global_zone_diff[i] += v;
745 }
746 }
747
748 for_each_online_pgdat(pgdat) {
749 struct per_cpu_nodestat *p;
750
751 p = per_cpu_ptr(pgdat->per_cpu_nodestats, cpu);
752
753 for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
754 if (p->vm_node_stat_diff[i]) {
755 int v;
756
757 v = p->vm_node_stat_diff[i];
758 p->vm_node_stat_diff[i] = 0;
759 atomic_long_add(v, &pgdat->vm_stat[i]);
760 global_node_diff[i] += v;
761 }
762 }
763
764 fold_diff(global_zone_diff, global_node_diff);
765}
766
767/*
768 * this is only called if !populated_zone(zone), which implies no other users of
769 * pset->vm_stat_diff[] exsist.
770 */
771void drain_zonestat(struct zone *zone, struct per_cpu_pageset *pset)
772{
773 int i;
774
775 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
776 if (pset->vm_stat_diff[i]) {
777 int v = pset->vm_stat_diff[i];
778 pset->vm_stat_diff[i] = 0;
779 atomic_long_add(v, &zone->vm_stat[i]);
780 atomic_long_add(v, &vm_zone_stat[i]);
781 }
782}
783#endif
784
785#ifdef CONFIG_NUMA
786/*
787 * Determine the per node value of a stat item. This function
788 * is called frequently in a NUMA machine, so try to be as
789 * frugal as possible.
790 */
791unsigned long sum_zone_node_page_state(int node,
792 enum zone_stat_item item)
793{
794 struct zone *zones = NODE_DATA(node)->node_zones;
795 int i;
796 unsigned long count = 0;
797
798 for (i = 0; i < MAX_NR_ZONES; i++)
799 count += zone_page_state(zones + i, item);
800
801 return count;
802}
803
804/*
805 * Determine the per node value of a stat item.
806 */
807unsigned long node_page_state(struct pglist_data *pgdat,
808 enum node_stat_item item)
809{
810 long x = atomic_long_read(&pgdat->vm_stat[item]);
811#ifdef CONFIG_SMP
812 if (x < 0)
813 x = 0;
814#endif
815 return x;
816}
817#endif
818
819#ifdef CONFIG_COMPACTION
820
821struct contig_page_info {
822 unsigned long free_pages;
823 unsigned long free_blocks_total;
824 unsigned long free_blocks_suitable;
825};
826
827/*
828 * Calculate the number of free pages in a zone, how many contiguous
829 * pages are free and how many are large enough to satisfy an allocation of
830 * the target size. Note that this function makes no attempt to estimate
831 * how many suitable free blocks there *might* be if MOVABLE pages were
832 * migrated. Calculating that is possible, but expensive and can be
833 * figured out from userspace
834 */
835static void fill_contig_page_info(struct zone *zone,
836 unsigned int suitable_order,
837 struct contig_page_info *info)
838{
839 unsigned int order;
840
841 info->free_pages = 0;
842 info->free_blocks_total = 0;
843 info->free_blocks_suitable = 0;
844
845 for (order = 0; order < MAX_ORDER; order++) {
846 unsigned long blocks;
847
848 /* Count number of free blocks */
849 blocks = zone->free_area[order].nr_free;
850 info->free_blocks_total += blocks;
851
852 /* Count free base pages */
853 info->free_pages += blocks << order;
854
855 /* Count the suitable free blocks */
856 if (order >= suitable_order)
857 info->free_blocks_suitable += blocks <<
858 (order - suitable_order);
859 }
860}
861
862/*
863 * A fragmentation index only makes sense if an allocation of a requested
864 * size would fail. If that is true, the fragmentation index indicates
865 * whether external fragmentation or a lack of memory was the problem.
866 * The value can be used to determine if page reclaim or compaction
867 * should be used
868 */
869static int __fragmentation_index(unsigned int order, struct contig_page_info *info)
870{
871 unsigned long requested = 1UL << order;
872
873 if (!info->free_blocks_total)
874 return 0;
875
876 /* Fragmentation index only makes sense when a request would fail */
877 if (info->free_blocks_suitable)
878 return -1000;
879
880 /*
881 * Index is between 0 and 1 so return within 3 decimal places
882 *
883 * 0 => allocation would fail due to lack of memory
884 * 1 => allocation would fail due to fragmentation
885 */
886 return 1000 - div_u64( (1000+(div_u64(info->free_pages * 1000ULL, requested))), info->free_blocks_total);
887}
888
889/* Same as __fragmentation index but allocs contig_page_info on stack */
890int fragmentation_index(struct zone *zone, unsigned int order)
891{
892 struct contig_page_info info;
893
894 fill_contig_page_info(zone, order, &info);
895 return __fragmentation_index(order, &info);
896}
897#endif
898
899#if defined(CONFIG_PROC_FS) || defined(CONFIG_SYSFS) || defined(CONFIG_NUMA)
900#ifdef CONFIG_ZONE_DMA
901#define TEXT_FOR_DMA(xx) xx "_dma",
902#else
903#define TEXT_FOR_DMA(xx)
904#endif
905
906#ifdef CONFIG_ZONE_DMA32
907#define TEXT_FOR_DMA32(xx) xx "_dma32",
908#else
909#define TEXT_FOR_DMA32(xx)
910#endif
911
912#ifdef CONFIG_HIGHMEM
913#define TEXT_FOR_HIGHMEM(xx) xx "_high",
914#else
915#define TEXT_FOR_HIGHMEM(xx)
916#endif
917
918#define TEXTS_FOR_ZONES(xx) TEXT_FOR_DMA(xx) TEXT_FOR_DMA32(xx) xx "_normal", \
919 TEXT_FOR_HIGHMEM(xx) xx "_movable",
920
921const char * const vmstat_text[] = {
922 /* enum zone_stat_item countes */
923 "nr_free_pages",
924 "nr_zone_inactive_anon",
925 "nr_zone_active_anon",
926 "nr_zone_inactive_file",
927 "nr_zone_active_file",
928 "nr_zone_unevictable",
929 "nr_zone_write_pending",
930 "nr_mlock",
931 "nr_slab_reclaimable",
932 "nr_slab_unreclaimable",
933 "nr_page_table_pages",
934 "nr_kernel_stack",
935 "nr_bounce",
936#if IS_ENABLED(CONFIG_ZSMALLOC)
937 "nr_zspages",
938#endif
939#ifdef CONFIG_NUMA
940 "numa_hit",
941 "numa_miss",
942 "numa_foreign",
943 "numa_interleave",
944 "numa_local",
945 "numa_other",
946#endif
947 "nr_free_cma",
948
949 /* Node-based counters */
950 "nr_inactive_anon",
951 "nr_active_anon",
952 "nr_inactive_file",
953 "nr_active_file",
954 "nr_unevictable",
955 "nr_isolated_anon",
956 "nr_isolated_file",
957 "nr_pages_scanned",
958 "workingset_refault",
959 "workingset_activate",
960 "workingset_nodereclaim",
961 "nr_anon_pages",
962 "nr_mapped",
963 "nr_file_pages",
964 "nr_dirty",
965 "nr_writeback",
966 "nr_writeback_temp",
967 "nr_shmem",
968 "nr_shmem_hugepages",
969 "nr_shmem_pmdmapped",
970 "nr_anon_transparent_hugepages",
971 "nr_unstable",
972 "nr_vmscan_write",
973 "nr_vmscan_immediate_reclaim",
974 "nr_dirtied",
975 "nr_written",
976
977 /* enum writeback_stat_item counters */
978 "nr_dirty_threshold",
979 "nr_dirty_background_threshold",
980
981#ifdef CONFIG_VM_EVENT_COUNTERS
982 /* enum vm_event_item counters */
983 "pgpgin",
984 "pgpgout",
985 "pswpin",
986 "pswpout",
987
988 TEXTS_FOR_ZONES("pgalloc")
989 TEXTS_FOR_ZONES("allocstall")
990 TEXTS_FOR_ZONES("pgskip")
991
992 "pgfree",
993 "pgactivate",
994 "pgdeactivate",
995
996 "pgfault",
997 "pgmajfault",
998 "pglazyfreed",
999
1000 "pgrefill",
1001 "pgsteal_kswapd",
1002 "pgsteal_direct",
1003 "pgscan_kswapd",
1004 "pgscan_direct",
1005 "pgscan_direct_throttle",
1006
1007#ifdef CONFIG_NUMA
1008 "zone_reclaim_failed",
1009#endif
1010 "pginodesteal",
1011 "slabs_scanned",
1012 "kswapd_inodesteal",
1013 "kswapd_low_wmark_hit_quickly",
1014 "kswapd_high_wmark_hit_quickly",
1015 "pageoutrun",
1016
1017 "pgrotated",
1018
1019 "drop_pagecache",
1020 "drop_slab",
1021
1022#ifdef CONFIG_NUMA_BALANCING
1023 "numa_pte_updates",
1024 "numa_huge_pte_updates",
1025 "numa_hint_faults",
1026 "numa_hint_faults_local",
1027 "numa_pages_migrated",
1028#endif
1029#ifdef CONFIG_MIGRATION
1030 "pgmigrate_success",
1031 "pgmigrate_fail",
1032#endif
1033#ifdef CONFIG_COMPACTION
1034 "compact_migrate_scanned",
1035 "compact_free_scanned",
1036 "compact_isolated",
1037 "compact_stall",
1038 "compact_fail",
1039 "compact_success",
1040 "compact_daemon_wake",
1041#endif
1042
1043#ifdef CONFIG_HUGETLB_PAGE
1044 "htlb_buddy_alloc_success",
1045 "htlb_buddy_alloc_fail",
1046#endif
1047 "unevictable_pgs_culled",
1048 "unevictable_pgs_scanned",
1049 "unevictable_pgs_rescued",
1050 "unevictable_pgs_mlocked",
1051 "unevictable_pgs_munlocked",
1052 "unevictable_pgs_cleared",
1053 "unevictable_pgs_stranded",
1054
1055#ifdef CONFIG_TRANSPARENT_HUGEPAGE
1056 "thp_fault_alloc",
1057 "thp_fault_fallback",
1058 "thp_collapse_alloc",
1059 "thp_collapse_alloc_failed",
1060 "thp_file_alloc",
1061 "thp_file_mapped",
1062 "thp_split_page",
1063 "thp_split_page_failed",
1064 "thp_deferred_split_page",
1065 "thp_split_pmd",
1066 "thp_zero_page_alloc",
1067 "thp_zero_page_alloc_failed",
1068#endif
1069#ifdef CONFIG_MEMORY_BALLOON
1070 "balloon_inflate",
1071 "balloon_deflate",
1072#ifdef CONFIG_BALLOON_COMPACTION
1073 "balloon_migrate",
1074#endif
1075#endif /* CONFIG_MEMORY_BALLOON */
1076#ifdef CONFIG_DEBUG_TLBFLUSH
1077#ifdef CONFIG_SMP
1078 "nr_tlb_remote_flush",
1079 "nr_tlb_remote_flush_received",
1080#endif /* CONFIG_SMP */
1081 "nr_tlb_local_flush_all",
1082 "nr_tlb_local_flush_one",
1083#endif /* CONFIG_DEBUG_TLBFLUSH */
1084
1085#ifdef CONFIG_DEBUG_VM_VMACACHE
1086 "vmacache_find_calls",
1087 "vmacache_find_hits",
1088 "vmacache_full_flushes",
1089#endif
1090#endif /* CONFIG_VM_EVENTS_COUNTERS */
1091};
1092#endif /* CONFIG_PROC_FS || CONFIG_SYSFS || CONFIG_NUMA */
1093
1094
1095#if (defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)) || \
1096 defined(CONFIG_PROC_FS)
1097static void *frag_start(struct seq_file *m, loff_t *pos)
1098{
1099 pg_data_t *pgdat;
1100 loff_t node = *pos;
1101
1102 for (pgdat = first_online_pgdat();
1103 pgdat && node;
1104 pgdat = next_online_pgdat(pgdat))
1105 --node;
1106
1107 return pgdat;
1108}
1109
1110static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
1111{
1112 pg_data_t *pgdat = (pg_data_t *)arg;
1113
1114 (*pos)++;
1115 return next_online_pgdat(pgdat);
1116}
1117
1118static void frag_stop(struct seq_file *m, void *arg)
1119{
1120}
1121
1122/* Walk all the zones in a node and print using a callback */
1123static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat,
1124 void (*print)(struct seq_file *m, pg_data_t *, struct zone *))
1125{
1126 struct zone *zone;
1127 struct zone *node_zones = pgdat->node_zones;
1128 unsigned long flags;
1129
1130 for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
1131 if (!populated_zone(zone))
1132 continue;
1133
1134 spin_lock_irqsave(&zone->lock, flags);
1135 print(m, pgdat, zone);
1136 spin_unlock_irqrestore(&zone->lock, flags);
1137 }
1138}
1139#endif
1140
1141#ifdef CONFIG_PROC_FS
1142static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,
1143 struct zone *zone)
1144{
1145 int order;
1146
1147 seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
1148 for (order = 0; order < MAX_ORDER; ++order)
1149 seq_printf(m, "%6lu ", zone->free_area[order].nr_free);
1150 seq_putc(m, '\n');
1151}
1152
1153/*
1154 * This walks the free areas for each zone.
1155 */
1156static int frag_show(struct seq_file *m, void *arg)
1157{
1158 pg_data_t *pgdat = (pg_data_t *)arg;
1159 walk_zones_in_node(m, pgdat, frag_show_print);
1160 return 0;
1161}
1162
1163static void pagetypeinfo_showfree_print(struct seq_file *m,
1164 pg_data_t *pgdat, struct zone *zone)
1165{
1166 int order, mtype;
1167
1168 for (mtype = 0; mtype < MIGRATE_TYPES; mtype++) {
1169 seq_printf(m, "Node %4d, zone %8s, type %12s ",
1170 pgdat->node_id,
1171 zone->name,
1172 migratetype_names[mtype]);
1173 for (order = 0; order < MAX_ORDER; ++order) {
1174 unsigned long freecount = 0;
1175 struct free_area *area;
1176 struct list_head *curr;
1177
1178 area = &(zone->free_area[order]);
1179
1180 list_for_each(curr, &area->free_list[mtype])
1181 freecount++;
1182 seq_printf(m, "%6lu ", freecount);
1183 }
1184 seq_putc(m, '\n');
1185 }
1186}
1187
1188/* Print out the free pages at each order for each migatetype */
1189static int pagetypeinfo_showfree(struct seq_file *m, void *arg)
1190{
1191 int order;
1192 pg_data_t *pgdat = (pg_data_t *)arg;
1193
1194 /* Print header */
1195 seq_printf(m, "%-43s ", "Free pages count per migrate type at order");
1196 for (order = 0; order < MAX_ORDER; ++order)
1197 seq_printf(m, "%6d ", order);
1198 seq_putc(m, '\n');
1199
1200 walk_zones_in_node(m, pgdat, pagetypeinfo_showfree_print);
1201
1202 return 0;
1203}
1204
1205static void pagetypeinfo_showblockcount_print(struct seq_file *m,
1206 pg_data_t *pgdat, struct zone *zone)
1207{
1208 int mtype;
1209 unsigned long pfn;
1210 unsigned long start_pfn = zone->zone_start_pfn;
1211 unsigned long end_pfn = zone_end_pfn(zone);
1212 unsigned long count[MIGRATE_TYPES] = { 0, };
1213
1214 for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
1215 struct page *page;
1216
1217 if (!pfn_valid(pfn))
1218 continue;
1219
1220 page = pfn_to_page(pfn);
1221
1222 /* Watch for unexpected holes punched in the memmap */
1223 if (!memmap_valid_within(pfn, page, zone))
1224 continue;
1225
1226 if (page_zone(page) != zone)
1227 continue;
1228
1229 mtype = get_pageblock_migratetype(page);
1230
1231 if (mtype < MIGRATE_TYPES)
1232 count[mtype]++;
1233 }
1234
1235 /* Print counts */
1236 seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
1237 for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
1238 seq_printf(m, "%12lu ", count[mtype]);
1239 seq_putc(m, '\n');
1240}
1241
1242/* Print out the free pages at each order for each migratetype */
1243static int pagetypeinfo_showblockcount(struct seq_file *m, void *arg)
1244{
1245 int mtype;
1246 pg_data_t *pgdat = (pg_data_t *)arg;
1247
1248 seq_printf(m, "\n%-23s", "Number of blocks type ");
1249 for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
1250 seq_printf(m, "%12s ", migratetype_names[mtype]);
1251 seq_putc(m, '\n');
1252 walk_zones_in_node(m, pgdat, pagetypeinfo_showblockcount_print);
1253
1254 return 0;
1255}
1256
1257/*
1258 * Print out the number of pageblocks for each migratetype that contain pages
1259 * of other types. This gives an indication of how well fallbacks are being
1260 * contained by rmqueue_fallback(). It requires information from PAGE_OWNER
1261 * to determine what is going on
1262 */
1263static void pagetypeinfo_showmixedcount(struct seq_file *m, pg_data_t *pgdat)
1264{
1265#ifdef CONFIG_PAGE_OWNER
1266 int mtype;
1267
1268 if (!static_branch_unlikely(&page_owner_inited))
1269 return;
1270
1271 drain_all_pages(NULL);
1272
1273 seq_printf(m, "\n%-23s", "Number of mixed blocks ");
1274 for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
1275 seq_printf(m, "%12s ", migratetype_names[mtype]);
1276 seq_putc(m, '\n');
1277
1278 walk_zones_in_node(m, pgdat, pagetypeinfo_showmixedcount_print);
1279#endif /* CONFIG_PAGE_OWNER */
1280}
1281
1282/*
1283 * This prints out statistics in relation to grouping pages by mobility.
1284 * It is expensive to collect so do not constantly read the file.
1285 */
1286static int pagetypeinfo_show(struct seq_file *m, void *arg)
1287{
1288 pg_data_t *pgdat = (pg_data_t *)arg;
1289
1290 /* check memoryless node */
1291 if (!node_state(pgdat->node_id, N_MEMORY))
1292 return 0;
1293
1294 seq_printf(m, "Page block order: %d\n", pageblock_order);
1295 seq_printf(m, "Pages per block: %lu\n", pageblock_nr_pages);
1296 seq_putc(m, '\n');
1297 pagetypeinfo_showfree(m, pgdat);
1298 pagetypeinfo_showblockcount(m, pgdat);
1299 pagetypeinfo_showmixedcount(m, pgdat);
1300
1301 return 0;
1302}
1303
1304static const struct seq_operations fragmentation_op = {
1305 .start = frag_start,
1306 .next = frag_next,
1307 .stop = frag_stop,
1308 .show = frag_show,
1309};
1310
1311static int fragmentation_open(struct inode *inode, struct file *file)
1312{
1313 return seq_open(file, &fragmentation_op);
1314}
1315
1316static const struct file_operations fragmentation_file_operations = {
1317 .open = fragmentation_open,
1318 .read = seq_read,
1319 .llseek = seq_lseek,
1320 .release = seq_release,
1321};
1322
1323static const struct seq_operations pagetypeinfo_op = {
1324 .start = frag_start,
1325 .next = frag_next,
1326 .stop = frag_stop,
1327 .show = pagetypeinfo_show,
1328};
1329
1330static int pagetypeinfo_open(struct inode *inode, struct file *file)
1331{
1332 return seq_open(file, &pagetypeinfo_op);
1333}
1334
1335static const struct file_operations pagetypeinfo_file_ops = {
1336 .open = pagetypeinfo_open,
1337 .read = seq_read,
1338 .llseek = seq_lseek,
1339 .release = seq_release,
1340};
1341
1342static bool is_zone_first_populated(pg_data_t *pgdat, struct zone *zone)
1343{
1344 int zid;
1345
1346 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
1347 struct zone *compare = &pgdat->node_zones[zid];
1348
1349 if (populated_zone(compare))
1350 return zone == compare;
1351 }
1352
1353 /* The zone must be somewhere! */
1354 WARN_ON_ONCE(1);
1355 return false;
1356}
1357
1358static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
1359 struct zone *zone)
1360{
1361 int i;
1362 seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name);
1363 if (is_zone_first_populated(pgdat, zone)) {
1364 seq_printf(m, "\n per-node stats");
1365 for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
1366 seq_printf(m, "\n %-12s %lu",
1367 vmstat_text[i + NR_VM_ZONE_STAT_ITEMS],
1368 node_page_state(pgdat, i));
1369 }
1370 }
1371 seq_printf(m,
1372 "\n pages free %lu"
1373 "\n min %lu"
1374 "\n low %lu"
1375 "\n high %lu"
1376 "\n node_scanned %lu"
1377 "\n spanned %lu"
1378 "\n present %lu"
1379 "\n managed %lu",
1380 zone_page_state(zone, NR_FREE_PAGES),
1381 min_wmark_pages(zone),
1382 low_wmark_pages(zone),
1383 high_wmark_pages(zone),
1384 node_page_state(zone->zone_pgdat, NR_PAGES_SCANNED),
1385 zone->spanned_pages,
1386 zone->present_pages,
1387 zone->managed_pages);
1388
1389 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
1390 seq_printf(m, "\n %-12s %lu", vmstat_text[i],
1391 zone_page_state(zone, i));
1392
1393 seq_printf(m,
1394 "\n protection: (%ld",
1395 zone->lowmem_reserve[0]);
1396 for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++)
1397 seq_printf(m, ", %ld", zone->lowmem_reserve[i]);
1398 seq_printf(m,
1399 ")"
1400 "\n pagesets");
1401 for_each_online_cpu(i) {
1402 struct per_cpu_pageset *pageset;
1403
1404 pageset = per_cpu_ptr(zone->pageset, i);
1405 seq_printf(m,
1406 "\n cpu: %i"
1407 "\n count: %i"
1408 "\n high: %i"
1409 "\n batch: %i",
1410 i,
1411 pageset->pcp.count,
1412 pageset->pcp.high,
1413 pageset->pcp.batch);
1414#ifdef CONFIG_SMP
1415 seq_printf(m, "\n vm stats threshold: %d",
1416 pageset->stat_threshold);
1417#endif
1418 }
1419 seq_printf(m,
1420 "\n node_unreclaimable: %u"
1421 "\n start_pfn: %lu"
1422 "\n node_inactive_ratio: %u",
1423 !pgdat_reclaimable(zone->zone_pgdat),
1424 zone->zone_start_pfn,
1425 zone->zone_pgdat->inactive_ratio);
1426 seq_putc(m, '\n');
1427}
1428
1429/*
1430 * Output information about zones in @pgdat.
1431 */
1432static int zoneinfo_show(struct seq_file *m, void *arg)
1433{
1434 pg_data_t *pgdat = (pg_data_t *)arg;
1435 walk_zones_in_node(m, pgdat, zoneinfo_show_print);
1436 return 0;
1437}
1438
1439static const struct seq_operations zoneinfo_op = {
1440 .start = frag_start, /* iterate over all zones. The same as in
1441 * fragmentation. */
1442 .next = frag_next,
1443 .stop = frag_stop,
1444 .show = zoneinfo_show,
1445};
1446
1447static int zoneinfo_open(struct inode *inode, struct file *file)
1448{
1449 return seq_open(file, &zoneinfo_op);
1450}
1451
1452static const struct file_operations proc_zoneinfo_file_operations = {
1453 .open = zoneinfo_open,
1454 .read = seq_read,
1455 .llseek = seq_lseek,
1456 .release = seq_release,
1457};
1458
1459enum writeback_stat_item {
1460 NR_DIRTY_THRESHOLD,
1461 NR_DIRTY_BG_THRESHOLD,
1462 NR_VM_WRITEBACK_STAT_ITEMS,
1463};
1464
1465static void *vmstat_start(struct seq_file *m, loff_t *pos)
1466{
1467 unsigned long *v;
1468 int i, stat_items_size;
1469
1470 if (*pos >= ARRAY_SIZE(vmstat_text))
1471 return NULL;
1472 stat_items_size = NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long) +
1473 NR_VM_NODE_STAT_ITEMS * sizeof(unsigned long) +
1474 NR_VM_WRITEBACK_STAT_ITEMS * sizeof(unsigned long);
1475
1476#ifdef CONFIG_VM_EVENT_COUNTERS
1477 stat_items_size += sizeof(struct vm_event_state);
1478#endif
1479
1480 v = kmalloc(stat_items_size, GFP_KERNEL);
1481 m->private = v;
1482 if (!v)
1483 return ERR_PTR(-ENOMEM);
1484 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
1485 v[i] = global_page_state(i);
1486 v += NR_VM_ZONE_STAT_ITEMS;
1487
1488 for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
1489 v[i] = global_node_page_state(i);
1490 v += NR_VM_NODE_STAT_ITEMS;
1491
1492 global_dirty_limits(v + NR_DIRTY_BG_THRESHOLD,
1493 v + NR_DIRTY_THRESHOLD);
1494 v += NR_VM_WRITEBACK_STAT_ITEMS;
1495
1496#ifdef CONFIG_VM_EVENT_COUNTERS
1497 all_vm_events(v);
1498 v[PGPGIN] /= 2; /* sectors -> kbytes */
1499 v[PGPGOUT] /= 2;
1500#endif
1501 return (unsigned long *)m->private + *pos;
1502}
1503
1504static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)
1505{
1506 (*pos)++;
1507 if (*pos >= ARRAY_SIZE(vmstat_text))
1508 return NULL;
1509 return (unsigned long *)m->private + *pos;
1510}
1511
1512static int vmstat_show(struct seq_file *m, void *arg)
1513{
1514 unsigned long *l = arg;
1515 unsigned long off = l - (unsigned long *)m->private;
1516
1517 seq_puts(m, vmstat_text[off]);
1518 seq_put_decimal_ull(m, " ", *l);
1519 seq_putc(m, '\n');
1520 return 0;
1521}
1522
1523static void vmstat_stop(struct seq_file *m, void *arg)
1524{
1525 kfree(m->private);
1526 m->private = NULL;
1527}
1528
1529static const struct seq_operations vmstat_op = {
1530 .start = vmstat_start,
1531 .next = vmstat_next,
1532 .stop = vmstat_stop,
1533 .show = vmstat_show,
1534};
1535
1536static int vmstat_open(struct inode *inode, struct file *file)
1537{
1538 return seq_open(file, &vmstat_op);
1539}
1540
1541static const struct file_operations proc_vmstat_file_operations = {
1542 .open = vmstat_open,
1543 .read = seq_read,
1544 .llseek = seq_lseek,
1545 .release = seq_release,
1546};
1547#endif /* CONFIG_PROC_FS */
1548
1549#ifdef CONFIG_SMP
1550static struct workqueue_struct *vmstat_wq;
1551static DEFINE_PER_CPU(struct delayed_work, vmstat_work);
1552int sysctl_stat_interval __read_mostly = HZ;
1553
1554#ifdef CONFIG_PROC_FS
1555static void refresh_vm_stats(struct work_struct *work)
1556{
1557 refresh_cpu_vm_stats(true);
1558}
1559
1560int vmstat_refresh(struct ctl_table *table, int write,
1561 void __user *buffer, size_t *lenp, loff_t *ppos)
1562{
1563 long val;
1564 int err;
1565 int i;
1566
1567 /*
1568 * The regular update, every sysctl_stat_interval, may come later
1569 * than expected: leaving a significant amount in per_cpu buckets.
1570 * This is particularly misleading when checking a quantity of HUGE
1571 * pages, immediately after running a test. /proc/sys/vm/stat_refresh,
1572 * which can equally be echo'ed to or cat'ted from (by root),
1573 * can be used to update the stats just before reading them.
1574 *
1575 * Oh, and since global_page_state() etc. are so careful to hide
1576 * transiently negative values, report an error here if any of
1577 * the stats is negative, so we know to go looking for imbalance.
1578 */
1579 err = schedule_on_each_cpu(refresh_vm_stats);
1580 if (err)
1581 return err;
1582 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) {
1583 val = atomic_long_read(&vm_zone_stat[i]);
1584 if (val < 0) {
1585 switch (i) {
1586 case NR_PAGES_SCANNED:
1587 /*
1588 * This is often seen to go negative in
1589 * recent kernels, but not to go permanently
1590 * negative. Whilst it would be nicer not to
1591 * have exceptions, rooting them out would be
1592 * another task, of rather low priority.
1593 */
1594 break;
1595 default:
1596 pr_warn("%s: %s %ld\n",
1597 __func__, vmstat_text[i], val);
1598 err = -EINVAL;
1599 break;
1600 }
1601 }
1602 }
1603 if (err)
1604 return err;
1605 if (write)
1606 *ppos += *lenp;
1607 else
1608 *lenp = 0;
1609 return 0;
1610}
1611#endif /* CONFIG_PROC_FS */
1612
1613static void vmstat_update(struct work_struct *w)
1614{
1615 if (refresh_cpu_vm_stats(true)) {
1616 /*
1617 * Counters were updated so we expect more updates
1618 * to occur in the future. Keep on running the
1619 * update worker thread.
1620 */
1621 queue_delayed_work_on(smp_processor_id(), vmstat_wq,
1622 this_cpu_ptr(&vmstat_work),
1623 round_jiffies_relative(sysctl_stat_interval));
1624 }
1625}
1626
1627/*
1628 * Switch off vmstat processing and then fold all the remaining differentials
1629 * until the diffs stay at zero. The function is used by NOHZ and can only be
1630 * invoked when tick processing is not active.
1631 */
1632/*
1633 * Check if the diffs for a certain cpu indicate that
1634 * an update is needed.
1635 */
1636static bool need_update(int cpu)
1637{
1638 struct zone *zone;
1639
1640 for_each_populated_zone(zone) {
1641 struct per_cpu_pageset *p = per_cpu_ptr(zone->pageset, cpu);
1642
1643 BUILD_BUG_ON(sizeof(p->vm_stat_diff[0]) != 1);
1644 /*
1645 * The fast way of checking if there are any vmstat diffs.
1646 * This works because the diffs are byte sized items.
1647 */
1648 if (memchr_inv(p->vm_stat_diff, 0, NR_VM_ZONE_STAT_ITEMS))
1649 return true;
1650
1651 }
1652 return false;
1653}
1654
1655/*
1656 * Switch off vmstat processing and then fold all the remaining differentials
1657 * until the diffs stay at zero. The function is used by NOHZ and can only be
1658 * invoked when tick processing is not active.
1659 */
1660void quiet_vmstat(void)
1661{
1662 if (system_state != SYSTEM_RUNNING)
1663 return;
1664
1665 if (!delayed_work_pending(this_cpu_ptr(&vmstat_work)))
1666 return;
1667
1668 if (!need_update(smp_processor_id()))
1669 return;
1670
1671 /*
1672 * Just refresh counters and do not care about the pending delayed
1673 * vmstat_update. It doesn't fire that often to matter and canceling
1674 * it would be too expensive from this path.
1675 * vmstat_shepherd will take care about that for us.
1676 */
1677 refresh_cpu_vm_stats(false);
1678}
1679
1680/*
1681 * Shepherd worker thread that checks the
1682 * differentials of processors that have their worker
1683 * threads for vm statistics updates disabled because of
1684 * inactivity.
1685 */
1686static void vmstat_shepherd(struct work_struct *w);
1687
1688static DECLARE_DEFERRABLE_WORK(shepherd, vmstat_shepherd);
1689
1690static void vmstat_shepherd(struct work_struct *w)
1691{
1692 int cpu;
1693
1694 get_online_cpus();
1695 /* Check processors whose vmstat worker threads have been disabled */
1696 for_each_online_cpu(cpu) {
1697 struct delayed_work *dw = &per_cpu(vmstat_work, cpu);
1698
1699 if (!delayed_work_pending(dw) && need_update(cpu))
1700 queue_delayed_work_on(cpu, vmstat_wq, dw, 0);
1701 }
1702 put_online_cpus();
1703
1704 schedule_delayed_work(&shepherd,
1705 round_jiffies_relative(sysctl_stat_interval));
1706}
1707
1708static void __init start_shepherd_timer(void)
1709{
1710 int cpu;
1711
1712 for_each_possible_cpu(cpu)
1713 INIT_DEFERRABLE_WORK(per_cpu_ptr(&vmstat_work, cpu),
1714 vmstat_update);
1715
1716 vmstat_wq = alloc_workqueue("vmstat", WQ_FREEZABLE|WQ_MEM_RECLAIM, 0);
1717 schedule_delayed_work(&shepherd,
1718 round_jiffies_relative(sysctl_stat_interval));
1719}
1720
1721static void __init init_cpu_node_state(void)
1722{
1723 int node;
1724
1725 for_each_online_node(node) {
1726 if (cpumask_weight(cpumask_of_node(node)) > 0)
1727 node_set_state(node, N_CPU);
1728 }
1729}
1730
1731static int vmstat_cpu_online(unsigned int cpu)
1732{
1733 refresh_zone_stat_thresholds();
1734 node_set_state(cpu_to_node(cpu), N_CPU);
1735 return 0;
1736}
1737
1738static int vmstat_cpu_down_prep(unsigned int cpu)
1739{
1740 cancel_delayed_work_sync(&per_cpu(vmstat_work, cpu));
1741 return 0;
1742}
1743
1744static int vmstat_cpu_dead(unsigned int cpu)
1745{
1746 const struct cpumask *node_cpus;
1747 int node;
1748
1749 node = cpu_to_node(cpu);
1750
1751 refresh_zone_stat_thresholds();
1752 node_cpus = cpumask_of_node(node);
1753 if (cpumask_weight(node_cpus) > 0)
1754 return 0;
1755
1756 node_clear_state(node, N_CPU);
1757 return 0;
1758}
1759
1760#endif
1761
1762static int __init setup_vmstat(void)
1763{
1764#ifdef CONFIG_SMP
1765 int ret;
1766
1767 ret = cpuhp_setup_state_nocalls(CPUHP_MM_VMSTAT_DEAD, "mm/vmstat:dead",
1768 NULL, vmstat_cpu_dead);
1769 if (ret < 0)
1770 pr_err("vmstat: failed to register 'dead' hotplug state\n");
1771
1772 ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "mm/vmstat:online",
1773 vmstat_cpu_online,
1774 vmstat_cpu_down_prep);
1775 if (ret < 0)
1776 pr_err("vmstat: failed to register 'online' hotplug state\n");
1777
1778 get_online_cpus();
1779 init_cpu_node_state();
1780 put_online_cpus();
1781
1782 start_shepherd_timer();
1783#endif
1784#ifdef CONFIG_PROC_FS
1785 proc_create("buddyinfo", S_IRUGO, NULL, &fragmentation_file_operations);
1786 proc_create("pagetypeinfo", S_IRUGO, NULL, &pagetypeinfo_file_ops);
1787 proc_create("vmstat", S_IRUGO, NULL, &proc_vmstat_file_operations);
1788 proc_create("zoneinfo", S_IRUGO, NULL, &proc_zoneinfo_file_operations);
1789#endif
1790 return 0;
1791}
1792module_init(setup_vmstat)
1793
1794#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)
1795
1796/*
1797 * Return an index indicating how much of the available free memory is
1798 * unusable for an allocation of the requested size.
1799 */
1800static int unusable_free_index(unsigned int order,
1801 struct contig_page_info *info)
1802{
1803 /* No free memory is interpreted as all free memory is unusable */
1804 if (info->free_pages == 0)
1805 return 1000;
1806
1807 /*
1808 * Index should be a value between 0 and 1. Return a value to 3
1809 * decimal places.
1810 *
1811 * 0 => no fragmentation
1812 * 1 => high fragmentation
1813 */
1814 return div_u64((info->free_pages - (info->free_blocks_suitable << order)) * 1000ULL, info->free_pages);
1815
1816}
1817
1818static void unusable_show_print(struct seq_file *m,
1819 pg_data_t *pgdat, struct zone *zone)
1820{
1821 unsigned int order;
1822 int index;
1823 struct contig_page_info info;
1824
1825 seq_printf(m, "Node %d, zone %8s ",
1826 pgdat->node_id,
1827 zone->name);
1828 for (order = 0; order < MAX_ORDER; ++order) {
1829 fill_contig_page_info(zone, order, &info);
1830 index = unusable_free_index(order, &info);
1831 seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
1832 }
1833
1834 seq_putc(m, '\n');
1835}
1836
1837/*
1838 * Display unusable free space index
1839 *
1840 * The unusable free space index measures how much of the available free
1841 * memory cannot be used to satisfy an allocation of a given size and is a
1842 * value between 0 and 1. The higher the value, the more of free memory is
1843 * unusable and by implication, the worse the external fragmentation is. This
1844 * can be expressed as a percentage by multiplying by 100.
1845 */
1846static int unusable_show(struct seq_file *m, void *arg)
1847{
1848 pg_data_t *pgdat = (pg_data_t *)arg;
1849
1850 /* check memoryless node */
1851 if (!node_state(pgdat->node_id, N_MEMORY))
1852 return 0;
1853
1854 walk_zones_in_node(m, pgdat, unusable_show_print);
1855
1856 return 0;
1857}
1858
1859static const struct seq_operations unusable_op = {
1860 .start = frag_start,
1861 .next = frag_next,
1862 .stop = frag_stop,
1863 .show = unusable_show,
1864};
1865
1866static int unusable_open(struct inode *inode, struct file *file)
1867{
1868 return seq_open(file, &unusable_op);
1869}
1870
1871static const struct file_operations unusable_file_ops = {
1872 .open = unusable_open,
1873 .read = seq_read,
1874 .llseek = seq_lseek,
1875 .release = seq_release,
1876};
1877
1878static void extfrag_show_print(struct seq_file *m,
1879 pg_data_t *pgdat, struct zone *zone)
1880{
1881 unsigned int order;
1882 int index;
1883
1884 /* Alloc on stack as interrupts are disabled for zone walk */
1885 struct contig_page_info info;
1886
1887 seq_printf(m, "Node %d, zone %8s ",
1888 pgdat->node_id,
1889 zone->name);
1890 for (order = 0; order < MAX_ORDER; ++order) {
1891 fill_contig_page_info(zone, order, &info);
1892 index = __fragmentation_index(order, &info);
1893 seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
1894 }
1895
1896 seq_putc(m, '\n');
1897}
1898
1899/*
1900 * Display fragmentation index for orders that allocations would fail for
1901 */
1902static int extfrag_show(struct seq_file *m, void *arg)
1903{
1904 pg_data_t *pgdat = (pg_data_t *)arg;
1905
1906 walk_zones_in_node(m, pgdat, extfrag_show_print);
1907
1908 return 0;
1909}
1910
1911static const struct seq_operations extfrag_op = {
1912 .start = frag_start,
1913 .next = frag_next,
1914 .stop = frag_stop,
1915 .show = extfrag_show,
1916};
1917
1918static int extfrag_open(struct inode *inode, struct file *file)
1919{
1920 return seq_open(file, &extfrag_op);
1921}
1922
1923static const struct file_operations extfrag_file_ops = {
1924 .open = extfrag_open,
1925 .read = seq_read,
1926 .llseek = seq_lseek,
1927 .release = seq_release,
1928};
1929
1930static int __init extfrag_debug_init(void)
1931{
1932 struct dentry *extfrag_debug_root;
1933
1934 extfrag_debug_root = debugfs_create_dir("extfrag", NULL);
1935 if (!extfrag_debug_root)
1936 return -ENOMEM;
1937
1938 if (!debugfs_create_file("unusable_index", 0444,
1939 extfrag_debug_root, NULL, &unusable_file_ops))
1940 goto fail;
1941
1942 if (!debugfs_create_file("extfrag_index", 0444,
1943 extfrag_debug_root, NULL, &extfrag_file_ops))
1944 goto fail;
1945
1946 return 0;
1947fail:
1948 debugfs_remove_recursive(extfrag_debug_root);
1949 return -ENOMEM;
1950}
1951
1952module_init(extfrag_debug_init);
1953#endif