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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
34 DEFINE_PER_CPU(struct vm_event_state, vm_event_states) = {{0}};
35 EXPORT_PER_CPU_SYMBOL(vm_event_states);
36
37 static 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 */
57 void all_vm_events(unsigned long *ret)
58 {
59 get_online_cpus();
60 sum_vm_events(ret);
61 put_online_cpus();
62 }
63 EXPORT_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 */
71 void 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 */
89 atomic_long_t vm_zone_stat[NR_VM_ZONE_STAT_ITEMS] __cacheline_aligned_in_smp;
90 atomic_long_t vm_node_stat[NR_VM_NODE_STAT_ITEMS] __cacheline_aligned_in_smp;
91 EXPORT_SYMBOL(vm_zone_stat);
92 EXPORT_SYMBOL(vm_node_stat);
93
94 #ifdef CONFIG_SMP
95
96 int 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
120 int 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 */
170 void 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
215 void 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 */
240 void __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 }
258 EXPORT_SYMBOL(__mod_zone_page_state);
259
260 void __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 }
278 EXPORT_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 */
303 void __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
319 void __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
335 void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
336 {
337 __inc_zone_state(page_zone(page), item);
338 }
339 EXPORT_SYMBOL(__inc_zone_page_state);
340
341 void __inc_node_page_state(struct page *page, enum node_stat_item item)
342 {
343 __inc_node_state(page_pgdat(page), item);
344 }
345 EXPORT_SYMBOL(__inc_node_page_state);
346
347 void __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
363 void __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
379 void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
380 {
381 __dec_zone_state(page_zone(page), item);
382 }
383 EXPORT_SYMBOL(__dec_zone_page_state);
384
385 void __dec_node_page_state(struct page *page, enum node_stat_item item)
386 {
387 __dec_node_state(page_pgdat(page), item);
388 }
389 EXPORT_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 */
404 static 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
442 void 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 }
447 EXPORT_SYMBOL(mod_zone_page_state);
448
449 void inc_zone_page_state(struct page *page, enum zone_stat_item item)
450 {
451 mod_zone_state(page_zone(page), item, 1, 1);
452 }
453 EXPORT_SYMBOL(inc_zone_page_state);
454
455 void dec_zone_page_state(struct page *page, enum zone_stat_item item)
456 {
457 mod_zone_state(page_zone(page), item, -1, -1);
458 }
459 EXPORT_SYMBOL(dec_zone_page_state);
460
461 static 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
499 void 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 }
504 EXPORT_SYMBOL(mod_node_page_state);
505
506 void inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
507 {
508 mod_node_state(pgdat, item, 1, 1);
509 }
510
511 void inc_node_page_state(struct page *page, enum node_stat_item item)
512 {
513 mod_node_state(page_pgdat(page), item, 1, 1);
514 }
515 EXPORT_SYMBOL(inc_node_page_state);
516
517 void dec_node_page_state(struct page *page, enum node_stat_item item)
518 {
519 mod_node_state(page_pgdat(page), item, -1, -1);
520 }
521 EXPORT_SYMBOL(dec_node_page_state);
522 #else
523 /*
524 * Use interrupt disable to serialize counter updates
525 */
526 void 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 }
535 EXPORT_SYMBOL(mod_zone_page_state);
536
537 void 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 }
547 EXPORT_SYMBOL(inc_zone_page_state);
548
549 void 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 }
557 EXPORT_SYMBOL(dec_zone_page_state);
558
559 void 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 }
567 EXPORT_SYMBOL(inc_node_state);
568
569 void 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 }
578 EXPORT_SYMBOL(mod_node_page_state);
579
580 void 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 }
590 EXPORT_SYMBOL(inc_node_page_state);
591
592 void 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 }
600 EXPORT_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 */
607 static 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 */
642 static 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 */
724 void 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 */
771 void 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 */
791 unsigned 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 */
807 unsigned 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
821 struct 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 */
835 static 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 */
869 static 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 */
890 int 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
921 const 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)
1097 static 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
1110 static 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
1118 static 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 */
1123 static 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
1142 static 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 */
1156 static 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
1163 static 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 */
1189 static 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
1205 static 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 */
1243 static 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 */
1263 static 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 */
1286 static 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
1304 static const struct seq_operations fragmentation_op = {
1305 .start = frag_start,
1306 .next = frag_next,
1307 .stop = frag_stop,
1308 .show = frag_show,
1309 };
1310
1311 static int fragmentation_open(struct inode *inode, struct file *file)
1312 {
1313 return seq_open(file, &fragmentation_op);
1314 }
1315
1316 static 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
1323 static const struct seq_operations pagetypeinfo_op = {
1324 .start = frag_start,
1325 .next = frag_next,
1326 .stop = frag_stop,
1327 .show = pagetypeinfo_show,
1328 };
1329
1330 static int pagetypeinfo_open(struct inode *inode, struct file *file)
1331 {
1332 return seq_open(file, &pagetypeinfo_op);
1333 }
1334
1335 static 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
1342 static 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
1358 static 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 */
1432 static 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
1439 static 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
1447 static int zoneinfo_open(struct inode *inode, struct file *file)
1448 {
1449 return seq_open(file, &zoneinfo_op);
1450 }
1451
1452 static 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
1459 enum writeback_stat_item {
1460 NR_DIRTY_THRESHOLD,
1461 NR_DIRTY_BG_THRESHOLD,
1462 NR_VM_WRITEBACK_STAT_ITEMS,
1463 };
1464
1465 static 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
1504 static 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
1512 static 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
1523 static void vmstat_stop(struct seq_file *m, void *arg)
1524 {
1525 kfree(m->private);
1526 m->private = NULL;
1527 }
1528
1529 static const struct seq_operations vmstat_op = {
1530 .start = vmstat_start,
1531 .next = vmstat_next,
1532 .stop = vmstat_stop,
1533 .show = vmstat_show,
1534 };
1535
1536 static int vmstat_open(struct inode *inode, struct file *file)
1537 {
1538 return seq_open(file, &vmstat_op);
1539 }
1540
1541 static 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
1550 static struct workqueue_struct *vmstat_wq;
1551 static DEFINE_PER_CPU(struct delayed_work, vmstat_work);
1552 int sysctl_stat_interval __read_mostly = HZ;
1553
1554 #ifdef CONFIG_PROC_FS
1555 static void refresh_vm_stats(struct work_struct *work)
1556 {
1557 refresh_cpu_vm_stats(true);
1558 }
1559
1560 int 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
1613 static 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 */
1636 static 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 */
1660 void 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 */
1686 static void vmstat_shepherd(struct work_struct *w);
1687
1688 static DECLARE_DEFERRABLE_WORK(shepherd, vmstat_shepherd);
1689
1690 static 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
1708 static 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
1721 static 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
1731 static 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
1738 static int vmstat_cpu_down_prep(unsigned int cpu)
1739 {
1740 cancel_delayed_work_sync(&per_cpu(vmstat_work, cpu));
1741 return 0;
1742 }
1743
1744 static 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
1762 static 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 }
1792 module_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 */
1800 static 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
1818 static 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 */
1846 static 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
1859 static const struct seq_operations unusable_op = {
1860 .start = frag_start,
1861 .next = frag_next,
1862 .stop = frag_stop,
1863 .show = unusable_show,
1864 };
1865
1866 static int unusable_open(struct inode *inode, struct file *file)
1867 {
1868 return seq_open(file, &unusable_op);
1869 }
1870
1871 static 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
1878 static 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 */
1902 static 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
1911 static const struct seq_operations extfrag_op = {
1912 .start = frag_start,
1913 .next = frag_next,
1914 .stop = frag_stop,
1915 .show = extfrag_show,
1916 };
1917
1918 static int extfrag_open(struct inode *inode, struct file *file)
1919 {
1920 return seq_open(file, &extfrag_op);
1921 }
1922
1923 static 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
1930 static 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;
1947 fail:
1948 debugfs_remove_recursive(extfrag_debug_root);
1949 return -ENOMEM;
1950 }
1951
1952 module_init(extfrag_debug_init);
1953 #endif