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vmstat.c
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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 <[email protected]>
10  */
11 #include <linux/fs.h>
12 #include <linux/mm.h>
13 #include <linux/err.h>
14 #include <linux/module.h>
15 #include <linux/slab.h>
16 #include <linux/cpu.h>
17 #include <linux/vmstat.h>
18 #include <linux/sched.h>
19 #include <linux/math64.h>
20 #include <linux/writeback.h>
21 #include <linux/compaction.h>
22 
23 #ifdef CONFIG_VM_EVENT_COUNTERS
24 DEFINE_PER_CPU(struct vm_event_state, vm_event_states) = {{0}};
25 EXPORT_PER_CPU_SYMBOL(vm_event_states);
26 
27 static void sum_vm_events(unsigned long *ret)
28 {
29  int cpu;
30  int i;
31 
32  memset(ret, 0, NR_VM_EVENT_ITEMS * sizeof(unsigned long));
33 
34  for_each_online_cpu(cpu) {
35  struct vm_event_state *this = &per_cpu(vm_event_states, cpu);
36 
37  for (i = 0; i < NR_VM_EVENT_ITEMS; i++)
38  ret[i] += this->event[i];
39  }
40 }
41 
42 /*
43  * Accumulate the vm event counters across all CPUs.
44  * The result is unavoidably approximate - it can change
45  * during and after execution of this function.
46 */
47 void all_vm_events(unsigned long *ret)
48 {
50  sum_vm_events(ret);
52 }
53 EXPORT_SYMBOL_GPL(all_vm_events);
54 
55 #ifdef CONFIG_HOTPLUG
56 /*
57  * Fold the foreign cpu events into our own.
58  *
59  * This is adding to the events on one processor
60  * but keeps the global counts constant.
61  */
62 void vm_events_fold_cpu(int cpu)
63 {
64  struct vm_event_state *fold_state = &per_cpu(vm_event_states, cpu);
65  int i;
66 
67  for (i = 0; i < NR_VM_EVENT_ITEMS; i++) {
68  count_vm_events(i, fold_state->event[i]);
69  fold_state->event[i] = 0;
70  }
71 }
72 #endif /* CONFIG_HOTPLUG */
73 
74 #endif /* CONFIG_VM_EVENT_COUNTERS */
75 
76 /*
77  * Manage combined zone based / global counters
78  *
79  * vm_stat contains the global counters
80  */
82 EXPORT_SYMBOL(vm_stat);
83 
84 #ifdef CONFIG_SMP
85 
86 int calculate_pressure_threshold(struct zone *zone)
87 {
88  int threshold;
89  int watermark_distance;
90 
91  /*
92  * As vmstats are not up to date, there is drift between the estimated
93  * and real values. For high thresholds and a high number of CPUs, it
94  * is possible for the min watermark to be breached while the estimated
95  * value looks fine. The pressure threshold is a reduced value such
96  * that even the maximum amount of drift will not accidentally breach
97  * the min watermark
98  */
99  watermark_distance = low_wmark_pages(zone) - min_wmark_pages(zone);
100  threshold = max(1, (int)(watermark_distance / num_online_cpus()));
101 
102  /*
103  * Maximum threshold is 125
104  */
105  threshold = min(125, threshold);
106 
107  return threshold;
108 }
109 
110 int calculate_normal_threshold(struct zone *zone)
111 {
112  int threshold;
113  int mem; /* memory in 128 MB units */
114 
115  /*
116  * The threshold scales with the number of processors and the amount
117  * of memory per zone. More memory means that we can defer updates for
118  * longer, more processors could lead to more contention.
119  * fls() is used to have a cheap way of logarithmic scaling.
120  *
121  * Some sample thresholds:
122  *
123  * Threshold Processors (fls) Zonesize fls(mem+1)
124  * ------------------------------------------------------------------
125  * 8 1 1 0.9-1 GB 4
126  * 16 2 2 0.9-1 GB 4
127  * 20 2 2 1-2 GB 5
128  * 24 2 2 2-4 GB 6
129  * 28 2 2 4-8 GB 7
130  * 32 2 2 8-16 GB 8
131  * 4 2 2 <128M 1
132  * 30 4 3 2-4 GB 5
133  * 48 4 3 8-16 GB 8
134  * 32 8 4 1-2 GB 4
135  * 32 8 4 0.9-1GB 4
136  * 10 16 5 <128M 1
137  * 40 16 5 900M 4
138  * 70 64 7 2-4 GB 5
139  * 84 64 7 4-8 GB 6
140  * 108 512 9 4-8 GB 6
141  * 125 1024 10 8-16 GB 8
142  * 125 1024 10 16-32 GB 9
143  */
144 
145  mem = zone->present_pages >> (27 - PAGE_SHIFT);
146 
147  threshold = 2 * fls(num_online_cpus()) * (1 + fls(mem));
148 
149  /*
150  * Maximum threshold is 125
151  */
152  threshold = min(125, threshold);
153 
154  return threshold;
155 }
156 
157 /*
158  * Refresh the thresholds for each zone.
159  */
160 void refresh_zone_stat_thresholds(void)
161 {
162  struct zone *zone;
163  int cpu;
164  int threshold;
165 
167  unsigned long max_drift, tolerate_drift;
168 
169  threshold = calculate_normal_threshold(zone);
170 
172  per_cpu_ptr(zone->pageset, cpu)->stat_threshold
173  = threshold;
174 
175  /*
176  * Only set percpu_drift_mark if there is a danger that
177  * NR_FREE_PAGES reports the low watermark is ok when in fact
178  * the min watermark could be breached by an allocation
179  */
180  tolerate_drift = low_wmark_pages(zone) - min_wmark_pages(zone);
181  max_drift = num_online_cpus() * threshold;
182  if (max_drift > tolerate_drift)
183  zone->percpu_drift_mark = high_wmark_pages(zone) +
184  max_drift;
185  }
186 }
187 
189  int (*calculate_pressure)(struct zone *))
190 {
191  struct zone *zone;
192  int cpu;
193  int threshold;
194  int i;
195 
196  for (i = 0; i < pgdat->nr_zones; i++) {
197  zone = &pgdat->node_zones[i];
198  if (!zone->percpu_drift_mark)
199  continue;
200 
201  threshold = (*calculate_pressure)(zone);
203  per_cpu_ptr(zone->pageset, cpu)->stat_threshold
204  = threshold;
205  }
206 }
207 
208 /*
209  * For use when we know that interrupts are disabled.
210  */
211 void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
212  int delta)
213 {
214  struct per_cpu_pageset __percpu *pcp = zone->pageset;
215  s8 __percpu *p = pcp->vm_stat_diff + item;
216  long x;
217  long t;
218 
219  x = delta + __this_cpu_read(*p);
220 
221  t = __this_cpu_read(pcp->stat_threshold);
222 
223  if (unlikely(x > t || x < -t)) {
224  zone_page_state_add(x, zone, item);
225  x = 0;
226  }
227  __this_cpu_write(*p, x);
228 }
229 EXPORT_SYMBOL(__mod_zone_page_state);
230 
231 /*
232  * Optimized increment and decrement functions.
233  *
234  * These are only for a single page and therefore can take a struct page *
235  * argument instead of struct zone *. This allows the inclusion of the code
236  * generated for page_zone(page) into the optimized functions.
237  *
238  * No overflow check is necessary and therefore the differential can be
239  * incremented or decremented in place which may allow the compilers to
240  * generate better code.
241  * The increment or decrement is known and therefore one boundary check can
242  * be omitted.
243  *
244  * NOTE: These functions are very performance sensitive. Change only
245  * with care.
246  *
247  * Some processors have inc/dec instructions that are atomic vs an interrupt.
248  * However, the code must first determine the differential location in a zone
249  * based on the processor number and then inc/dec the counter. There is no
250  * guarantee without disabling preemption that the processor will not change
251  * in between and therefore the atomicity vs. interrupt cannot be exploited
252  * in a useful way here.
253  */
254 void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
255 {
256  struct per_cpu_pageset __percpu *pcp = zone->pageset;
257  s8 __percpu *p = pcp->vm_stat_diff + item;
258  s8 v, t;
259 
260  v = __this_cpu_inc_return(*p);
261  t = __this_cpu_read(pcp->stat_threshold);
262  if (unlikely(v > t)) {
263  s8 overstep = t >> 1;
264 
265  zone_page_state_add(v + overstep, zone, item);
266  __this_cpu_write(*p, -overstep);
267  }
268 }
269 
270 void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
271 {
272  __inc_zone_state(page_zone(page), item);
273 }
274 EXPORT_SYMBOL(__inc_zone_page_state);
275 
276 void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
277 {
278  struct per_cpu_pageset __percpu *pcp = zone->pageset;
279  s8 __percpu *p = pcp->vm_stat_diff + item;
280  s8 v, t;
281 
282  v = __this_cpu_dec_return(*p);
283  t = __this_cpu_read(pcp->stat_threshold);
284  if (unlikely(v < - t)) {
285  s8 overstep = t >> 1;
286 
287  zone_page_state_add(v - overstep, zone, item);
288  __this_cpu_write(*p, overstep);
289  }
290 }
291 
292 void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
293 {
294  __dec_zone_state(page_zone(page), item);
295 }
296 EXPORT_SYMBOL(__dec_zone_page_state);
297 
298 #ifdef CONFIG_HAVE_CMPXCHG_LOCAL
299 /*
300  * If we have cmpxchg_local support then we do not need to incur the overhead
301  * that comes with local_irq_save/restore if we use this_cpu_cmpxchg.
302  *
303  * mod_state() modifies the zone counter state through atomic per cpu
304  * operations.
305  *
306  * Overstep mode specifies how overstep should handled:
307  * 0 No overstepping
308  * 1 Overstepping half of threshold
309  * -1 Overstepping minus half of threshold
310 */
311 static inline void mod_state(struct zone *zone,
312  enum zone_stat_item item, int delta, int overstep_mode)
313 {
314  struct per_cpu_pageset __percpu *pcp = zone->pageset;
315  s8 __percpu *p = pcp->vm_stat_diff + item;
316  long o, n, t, z;
317 
318  do {
319  z = 0; /* overflow to zone counters */
320 
321  /*
322  * The fetching of the stat_threshold is racy. We may apply
323  * a counter threshold to the wrong the cpu if we get
324  * rescheduled while executing here. However, the next
325  * counter update will apply the threshold again and
326  * therefore bring the counter under the threshold again.
327  *
328  * Most of the time the thresholds are the same anyways
329  * for all cpus in a zone.
330  */
331  t = this_cpu_read(pcp->stat_threshold);
332 
333  o = this_cpu_read(*p);
334  n = delta + o;
335 
336  if (n > t || n < -t) {
337  int os = overstep_mode * (t >> 1) ;
338 
339  /* Overflow must be added to zone counters */
340  z = n + os;
341  n = -os;
342  }
343  } while (this_cpu_cmpxchg(*p, o, n) != o);
344 
345  if (z)
346  zone_page_state_add(z, zone, item);
347 }
348 
349 void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
350  int delta)
351 {
352  mod_state(zone, item, delta, 0);
353 }
355 
356 void inc_zone_state(struct zone *zone, enum zone_stat_item item)
357 {
358  mod_state(zone, item, 1, 1);
359 }
360 
361 void inc_zone_page_state(struct page *page, enum zone_stat_item item)
362 {
363  mod_state(page_zone(page), item, 1, 1);
364 }
366 
367 void dec_zone_page_state(struct page *page, enum zone_stat_item item)
368 {
369  mod_state(page_zone(page), item, -1, -1);
370 }
372 #else
373 /*
374  * Use interrupt disable to serialize counter updates
375  */
376 void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
377  int delta)
378 {
379  unsigned long flags;
380 
381  local_irq_save(flags);
382  __mod_zone_page_state(zone, item, delta);
383  local_irq_restore(flags);
384 }
386 
387 void inc_zone_state(struct zone *zone, enum zone_stat_item item)
388 {
389  unsigned long flags;
390 
391  local_irq_save(flags);
392  __inc_zone_state(zone, item);
393  local_irq_restore(flags);
394 }
395 
396 void inc_zone_page_state(struct page *page, enum zone_stat_item item)
397 {
398  unsigned long flags;
399  struct zone *zone;
400 
401  zone = page_zone(page);
402  local_irq_save(flags);
403  __inc_zone_state(zone, item);
404  local_irq_restore(flags);
405 }
407 
408 void dec_zone_page_state(struct page *page, enum zone_stat_item item)
409 {
410  unsigned long flags;
411 
412  local_irq_save(flags);
413  __dec_zone_page_state(page, item);
414  local_irq_restore(flags);
415 }
417 #endif
418 
419 /*
420  * Update the zone counters for one cpu.
421  *
422  * The cpu specified must be either the current cpu or a processor that
423  * is not online. If it is the current cpu then the execution thread must
424  * be pinned to the current cpu.
425  *
426  * Note that refresh_cpu_vm_stats strives to only access
427  * node local memory. The per cpu pagesets on remote zones are placed
428  * in the memory local to the processor using that pageset. So the
429  * loop over all zones will access a series of cachelines local to
430  * the processor.
431  *
432  * The call to zone_page_state_add updates the cachelines with the
433  * statistics in the remote zone struct as well as the global cachelines
434  * with the global counters. These could cause remote node cache line
435  * bouncing and will have to be only done when necessary.
436  */
437 void refresh_cpu_vm_stats(int cpu)
438 {
439  struct zone *zone;
440  int i;
441  int global_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
442 
444  struct per_cpu_pageset *p;
445 
446  p = per_cpu_ptr(zone->pageset, cpu);
447 
448  for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
449  if (p->vm_stat_diff[i]) {
450  unsigned long flags;
451  int v;
452 
453  local_irq_save(flags);
454  v = p->vm_stat_diff[i];
455  p->vm_stat_diff[i] = 0;
456  local_irq_restore(flags);
457  atomic_long_add(v, &zone->vm_stat[i]);
458  global_diff[i] += v;
459 #ifdef CONFIG_NUMA
460  /* 3 seconds idle till flush */
461  p->expire = 3;
462 #endif
463  }
464  cond_resched();
465 #ifdef CONFIG_NUMA
466  /*
467  * Deal with draining the remote pageset of this
468  * processor
469  *
470  * Check if there are pages remaining in this pageset
471  * if not then there is nothing to expire.
472  */
473  if (!p->expire || !p->pcp.count)
474  continue;
475 
476  /*
477  * We never drain zones local to this processor.
478  */
479  if (zone_to_nid(zone) == numa_node_id()) {
480  p->expire = 0;
481  continue;
482  }
483 
484  p->expire--;
485  if (p->expire)
486  continue;
487 
488  if (p->pcp.count)
489  drain_zone_pages(zone, &p->pcp);
490 #endif
491  }
492 
493  for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
494  if (global_diff[i])
495  atomic_long_add(global_diff[i], &vm_stat[i]);
496 }
497 
498 void drain_zonestat(struct zone *zone, struct per_cpu_pageset *pset)
499 {
500  int i;
501 
502  for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
503  if (pset->vm_stat_diff[i]) {
504  int v = pset->vm_stat_diff[i];
505  pset->vm_stat_diff[i] = 0;
506  atomic_long_add(v, &zone->vm_stat[i]);
507  atomic_long_add(v, &vm_stat[i]);
508  }
509 }
510 #endif
511 
512 #ifdef CONFIG_NUMA
513 /*
514  * zonelist = the list of zones passed to the allocator
515  * z = the zone from which the allocation occurred.
516  *
517  * Must be called with interrupts disabled.
518  *
519  * When __GFP_OTHER_NODE is set assume the node of the preferred
520  * zone is the local node. This is useful for daemons who allocate
521  * memory on behalf of other processes.
522  */
523 void zone_statistics(struct zone *preferred_zone, struct zone *z, gfp_t flags)
524 {
525  if (z->zone_pgdat == preferred_zone->zone_pgdat) {
526  __inc_zone_state(z, NUMA_HIT);
527  } else {
528  __inc_zone_state(z, NUMA_MISS);
529  __inc_zone_state(preferred_zone, NUMA_FOREIGN);
530  }
531  if (z->node == ((flags & __GFP_OTHER_NODE) ?
532  preferred_zone->node : numa_node_id()))
533  __inc_zone_state(z, NUMA_LOCAL);
534  else
535  __inc_zone_state(z, NUMA_OTHER);
536 }
537 #endif
538 
539 #ifdef CONFIG_COMPACTION
540 
541 struct contig_page_info {
542  unsigned long free_pages;
543  unsigned long free_blocks_total;
544  unsigned long free_blocks_suitable;
545 };
546 
547 /*
548  * Calculate the number of free pages in a zone, how many contiguous
549  * pages are free and how many are large enough to satisfy an allocation of
550  * the target size. Note that this function makes no attempt to estimate
551  * how many suitable free blocks there *might* be if MOVABLE pages were
552  * migrated. Calculating that is possible, but expensive and can be
553  * figured out from userspace
554  */
555 static void fill_contig_page_info(struct zone *zone,
556  unsigned int suitable_order,
557  struct contig_page_info *info)
558 {
559  unsigned int order;
560 
561  info->free_pages = 0;
562  info->free_blocks_total = 0;
563  info->free_blocks_suitable = 0;
564 
565  for (order = 0; order < MAX_ORDER; order++) {
566  unsigned long blocks;
567 
568  /* Count number of free blocks */
569  blocks = zone->free_area[order].nr_free;
570  info->free_blocks_total += blocks;
571 
572  /* Count free base pages */
573  info->free_pages += blocks << order;
574 
575  /* Count the suitable free blocks */
576  if (order >= suitable_order)
577  info->free_blocks_suitable += blocks <<
578  (order - suitable_order);
579  }
580 }
581 
582 /*
583  * A fragmentation index only makes sense if an allocation of a requested
584  * size would fail. If that is true, the fragmentation index indicates
585  * whether external fragmentation or a lack of memory was the problem.
586  * The value can be used to determine if page reclaim or compaction
587  * should be used
588  */
589 static int __fragmentation_index(unsigned int order, struct contig_page_info *info)
590 {
591  unsigned long requested = 1UL << order;
592 
593  if (!info->free_blocks_total)
594  return 0;
595 
596  /* Fragmentation index only makes sense when a request would fail */
597  if (info->free_blocks_suitable)
598  return -1000;
599 
600  /*
601  * Index is between 0 and 1 so return within 3 decimal places
602  *
603  * 0 => allocation would fail due to lack of memory
604  * 1 => allocation would fail due to fragmentation
605  */
606  return 1000 - div_u64( (1000+(div_u64(info->free_pages * 1000ULL, requested))), info->free_blocks_total);
607 }
608 
609 /* Same as __fragmentation index but allocs contig_page_info on stack */
610 int fragmentation_index(struct zone *zone, unsigned int order)
611 {
612  struct contig_page_info info;
613 
614  fill_contig_page_info(zone, order, &info);
615  return __fragmentation_index(order, &info);
616 }
617 #endif
618 
619 #if defined(CONFIG_PROC_FS) || defined(CONFIG_COMPACTION)
620 #include <linux/proc_fs.h>
621 #include <linux/seq_file.h>
622 
623 static char * const migratetype_names[MIGRATE_TYPES] = {
624  "Unmovable",
625  "Reclaimable",
626  "Movable",
627  "Reserve",
628 #ifdef CONFIG_CMA
629  "CMA",
630 #endif
631  "Isolate",
632 };
633 
634 static void *frag_start(struct seq_file *m, loff_t *pos)
635 {
636  pg_data_t *pgdat;
637  loff_t node = *pos;
638  for (pgdat = first_online_pgdat();
639  pgdat && node;
640  pgdat = next_online_pgdat(pgdat))
641  --node;
642 
643  return pgdat;
644 }
645 
646 static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
647 {
648  pg_data_t *pgdat = (pg_data_t *)arg;
649 
650  (*pos)++;
651  return next_online_pgdat(pgdat);
652 }
653 
654 static void frag_stop(struct seq_file *m, void *arg)
655 {
656 }
657 
658 /* Walk all the zones in a node and print using a callback */
659 static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat,
660  void (*print)(struct seq_file *m, pg_data_t *, struct zone *))
661 {
662  struct zone *zone;
663  struct zone *node_zones = pgdat->node_zones;
664  unsigned long flags;
665 
666  for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
667  if (!populated_zone(zone))
668  continue;
669 
670  spin_lock_irqsave(&zone->lock, flags);
671  print(m, pgdat, zone);
672  spin_unlock_irqrestore(&zone->lock, flags);
673  }
674 }
675 #endif
676 
677 #if defined(CONFIG_PROC_FS) || defined(CONFIG_SYSFS) || defined(CONFIG_NUMA)
678 #ifdef CONFIG_ZONE_DMA
679 #define TEXT_FOR_DMA(xx) xx "_dma",
680 #else
681 #define TEXT_FOR_DMA(xx)
682 #endif
683 
684 #ifdef CONFIG_ZONE_DMA32
685 #define TEXT_FOR_DMA32(xx) xx "_dma32",
686 #else
687 #define TEXT_FOR_DMA32(xx)
688 #endif
689 
690 #ifdef CONFIG_HIGHMEM
691 #define TEXT_FOR_HIGHMEM(xx) xx "_high",
692 #else
693 #define TEXT_FOR_HIGHMEM(xx)
694 #endif
695 
696 #define TEXTS_FOR_ZONES(xx) TEXT_FOR_DMA(xx) TEXT_FOR_DMA32(xx) xx "_normal", \
697  TEXT_FOR_HIGHMEM(xx) xx "_movable",
698 
699 const char * const vmstat_text[] = {
700  /* Zoned VM counters */
701  "nr_free_pages",
702  "nr_inactive_anon",
703  "nr_active_anon",
704  "nr_inactive_file",
705  "nr_active_file",
706  "nr_unevictable",
707  "nr_mlock",
708  "nr_anon_pages",
709  "nr_mapped",
710  "nr_file_pages",
711  "nr_dirty",
712  "nr_writeback",
713  "nr_slab_reclaimable",
714  "nr_slab_unreclaimable",
715  "nr_page_table_pages",
716  "nr_kernel_stack",
717  "nr_unstable",
718  "nr_bounce",
719  "nr_vmscan_write",
720  "nr_vmscan_immediate_reclaim",
721  "nr_writeback_temp",
722  "nr_isolated_anon",
723  "nr_isolated_file",
724  "nr_shmem",
725  "nr_dirtied",
726  "nr_written",
727 
728 #ifdef CONFIG_NUMA
729  "numa_hit",
730  "numa_miss",
731  "numa_foreign",
732  "numa_interleave",
733  "numa_local",
734  "numa_other",
735 #endif
736  "nr_anon_transparent_hugepages",
737  "nr_free_cma",
738  "nr_dirty_threshold",
739  "nr_dirty_background_threshold",
740 
741 #ifdef CONFIG_VM_EVENT_COUNTERS
742  "pgpgin",
743  "pgpgout",
744  "pswpin",
745  "pswpout",
746 
747  TEXTS_FOR_ZONES("pgalloc")
748 
749  "pgfree",
750  "pgactivate",
751  "pgdeactivate",
752 
753  "pgfault",
754  "pgmajfault",
755 
756  TEXTS_FOR_ZONES("pgrefill")
757  TEXTS_FOR_ZONES("pgsteal_kswapd")
758  TEXTS_FOR_ZONES("pgsteal_direct")
759  TEXTS_FOR_ZONES("pgscan_kswapd")
760  TEXTS_FOR_ZONES("pgscan_direct")
761  "pgscan_direct_throttle",
762 
763 #ifdef CONFIG_NUMA
764  "zone_reclaim_failed",
765 #endif
766  "pginodesteal",
767  "slabs_scanned",
768  "kswapd_inodesteal",
769  "kswapd_low_wmark_hit_quickly",
770  "kswapd_high_wmark_hit_quickly",
771  "kswapd_skip_congestion_wait",
772  "pageoutrun",
773  "allocstall",
774 
775  "pgrotated",
776 
777 #ifdef CONFIG_COMPACTION
778  "compact_blocks_moved",
779  "compact_pages_moved",
780  "compact_pagemigrate_failed",
781  "compact_stall",
782  "compact_fail",
783  "compact_success",
784 #endif
785 
786 #ifdef CONFIG_HUGETLB_PAGE
787  "htlb_buddy_alloc_success",
788  "htlb_buddy_alloc_fail",
789 #endif
790  "unevictable_pgs_culled",
791  "unevictable_pgs_scanned",
792  "unevictable_pgs_rescued",
793  "unevictable_pgs_mlocked",
794  "unevictable_pgs_munlocked",
795  "unevictable_pgs_cleared",
796  "unevictable_pgs_stranded",
797 
798 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
799  "thp_fault_alloc",
800  "thp_fault_fallback",
801  "thp_collapse_alloc",
802  "thp_collapse_alloc_failed",
803  "thp_split",
804 #endif
805 
806 #endif /* CONFIG_VM_EVENTS_COUNTERS */
807 };
808 #endif /* CONFIG_PROC_FS || CONFIG_SYSFS || CONFIG_NUMA */
809 
810 
811 #ifdef CONFIG_PROC_FS
812 static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,
813  struct zone *zone)
814 {
815  int order;
816 
817  seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
818  for (order = 0; order < MAX_ORDER; ++order)
819  seq_printf(m, "%6lu ", zone->free_area[order].nr_free);
820  seq_putc(m, '\n');
821 }
822 
823 /*
824  * This walks the free areas for each zone.
825  */
826 static int frag_show(struct seq_file *m, void *arg)
827 {
828  pg_data_t *pgdat = (pg_data_t *)arg;
829  walk_zones_in_node(m, pgdat, frag_show_print);
830  return 0;
831 }
832 
833 static void pagetypeinfo_showfree_print(struct seq_file *m,
834  pg_data_t *pgdat, struct zone *zone)
835 {
836  int order, mtype;
837 
838  for (mtype = 0; mtype < MIGRATE_TYPES; mtype++) {
839  seq_printf(m, "Node %4d, zone %8s, type %12s ",
840  pgdat->node_id,
841  zone->name,
842  migratetype_names[mtype]);
843  for (order = 0; order < MAX_ORDER; ++order) {
844  unsigned long freecount = 0;
845  struct free_area *area;
846  struct list_head *curr;
847 
848  area = &(zone->free_area[order]);
849 
850  list_for_each(curr, &area->free_list[mtype])
851  freecount++;
852  seq_printf(m, "%6lu ", freecount);
853  }
854  seq_putc(m, '\n');
855  }
856 }
857 
858 /* Print out the free pages at each order for each migatetype */
859 static int pagetypeinfo_showfree(struct seq_file *m, void *arg)
860 {
861  int order;
862  pg_data_t *pgdat = (pg_data_t *)arg;
863 
864  /* Print header */
865  seq_printf(m, "%-43s ", "Free pages count per migrate type at order");
866  for (order = 0; order < MAX_ORDER; ++order)
867  seq_printf(m, "%6d ", order);
868  seq_putc(m, '\n');
869 
870  walk_zones_in_node(m, pgdat, pagetypeinfo_showfree_print);
871 
872  return 0;
873 }
874 
875 static void pagetypeinfo_showblockcount_print(struct seq_file *m,
876  pg_data_t *pgdat, struct zone *zone)
877 {
878  int mtype;
879  unsigned long pfn;
880  unsigned long start_pfn = zone->zone_start_pfn;
881  unsigned long end_pfn = start_pfn + zone->spanned_pages;
882  unsigned long count[MIGRATE_TYPES] = { 0, };
883 
884  for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
885  struct page *page;
886 
887  if (!pfn_valid(pfn))
888  continue;
889 
890  page = pfn_to_page(pfn);
891 
892  /* Watch for unexpected holes punched in the memmap */
893  if (!memmap_valid_within(pfn, page, zone))
894  continue;
895 
896  mtype = get_pageblock_migratetype(page);
897 
898  if (mtype < MIGRATE_TYPES)
899  count[mtype]++;
900  }
901 
902  /* Print counts */
903  seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
904  for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
905  seq_printf(m, "%12lu ", count[mtype]);
906  seq_putc(m, '\n');
907 }
908 
909 /* Print out the free pages at each order for each migratetype */
910 static int pagetypeinfo_showblockcount(struct seq_file *m, void *arg)
911 {
912  int mtype;
913  pg_data_t *pgdat = (pg_data_t *)arg;
914 
915  seq_printf(m, "\n%-23s", "Number of blocks type ");
916  for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
917  seq_printf(m, "%12s ", migratetype_names[mtype]);
918  seq_putc(m, '\n');
919  walk_zones_in_node(m, pgdat, pagetypeinfo_showblockcount_print);
920 
921  return 0;
922 }
923 
924 /*
925  * This prints out statistics in relation to grouping pages by mobility.
926  * It is expensive to collect so do not constantly read the file.
927  */
928 static int pagetypeinfo_show(struct seq_file *m, void *arg)
929 {
930  pg_data_t *pgdat = (pg_data_t *)arg;
931 
932  /* check memoryless node */
933  if (!node_state(pgdat->node_id, N_HIGH_MEMORY))
934  return 0;
935 
936  seq_printf(m, "Page block order: %d\n", pageblock_order);
937  seq_printf(m, "Pages per block: %lu\n", pageblock_nr_pages);
938  seq_putc(m, '\n');
939  pagetypeinfo_showfree(m, pgdat);
940  pagetypeinfo_showblockcount(m, pgdat);
941 
942  return 0;
943 }
944 
945 static const struct seq_operations fragmentation_op = {
946  .start = frag_start,
947  .next = frag_next,
948  .stop = frag_stop,
949  .show = frag_show,
950 };
951 
952 static int fragmentation_open(struct inode *inode, struct file *file)
953 {
954  return seq_open(file, &fragmentation_op);
955 }
956 
957 static const struct file_operations fragmentation_file_operations = {
958  .open = fragmentation_open,
959  .read = seq_read,
960  .llseek = seq_lseek,
961  .release = seq_release,
962 };
963 
964 static const struct seq_operations pagetypeinfo_op = {
965  .start = frag_start,
966  .next = frag_next,
967  .stop = frag_stop,
968  .show = pagetypeinfo_show,
969 };
970 
971 static int pagetypeinfo_open(struct inode *inode, struct file *file)
972 {
973  return seq_open(file, &pagetypeinfo_op);
974 }
975 
976 static const struct file_operations pagetypeinfo_file_ops = {
977  .open = pagetypeinfo_open,
978  .read = seq_read,
979  .llseek = seq_lseek,
980  .release = seq_release,
981 };
982 
983 static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
984  struct zone *zone)
985 {
986  int i;
987  seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name);
988  seq_printf(m,
989  "\n pages free %lu"
990  "\n min %lu"
991  "\n low %lu"
992  "\n high %lu"
993  "\n scanned %lu"
994  "\n spanned %lu"
995  "\n present %lu",
996  zone_page_state(zone, NR_FREE_PAGES),
997  min_wmark_pages(zone),
998  low_wmark_pages(zone),
999  high_wmark_pages(zone),
1000  zone->pages_scanned,
1001  zone->spanned_pages,
1002  zone->present_pages);
1003 
1004  for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
1005  seq_printf(m, "\n %-12s %lu", vmstat_text[i],
1006  zone_page_state(zone, i));
1007 
1008  seq_printf(m,
1009  "\n protection: (%lu",
1010  zone->lowmem_reserve[0]);
1011  for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++)
1012  seq_printf(m, ", %lu", zone->lowmem_reserve[i]);
1013  seq_printf(m,
1014  ")"
1015  "\n pagesets");
1016  for_each_online_cpu(i) {
1017  struct per_cpu_pageset *pageset;
1018 
1019  pageset = per_cpu_ptr(zone->pageset, i);
1020  seq_printf(m,
1021  "\n cpu: %i"
1022  "\n count: %i"
1023  "\n high: %i"
1024  "\n batch: %i",
1025  i,
1026  pageset->pcp.count,
1027  pageset->pcp.high,
1028  pageset->pcp.batch);
1029 #ifdef CONFIG_SMP
1030  seq_printf(m, "\n vm stats threshold: %d",
1031  pageset->stat_threshold);
1032 #endif
1033  }
1034  seq_printf(m,
1035  "\n all_unreclaimable: %u"
1036  "\n start_pfn: %lu"
1037  "\n inactive_ratio: %u",
1038  zone->all_unreclaimable,
1039  zone->zone_start_pfn,
1040  zone->inactive_ratio);
1041  seq_putc(m, '\n');
1042 }
1043 
1044 /*
1045  * Output information about zones in @pgdat.
1046  */
1047 static int zoneinfo_show(struct seq_file *m, void *arg)
1048 {
1049  pg_data_t *pgdat = (pg_data_t *)arg;
1050  walk_zones_in_node(m, pgdat, zoneinfo_show_print);
1051  return 0;
1052 }
1053 
1054 static const struct seq_operations zoneinfo_op = {
1055  .start = frag_start, /* iterate over all zones. The same as in
1056  * fragmentation. */
1057  .next = frag_next,
1058  .stop = frag_stop,
1059  .show = zoneinfo_show,
1060 };
1061 
1062 static int zoneinfo_open(struct inode *inode, struct file *file)
1063 {
1064  return seq_open(file, &zoneinfo_op);
1065 }
1066 
1067 static const struct file_operations proc_zoneinfo_file_operations = {
1068  .open = zoneinfo_open,
1069  .read = seq_read,
1070  .llseek = seq_lseek,
1071  .release = seq_release,
1072 };
1073 
1074 enum writeback_stat_item {
1075  NR_DIRTY_THRESHOLD,
1076  NR_DIRTY_BG_THRESHOLD,
1077  NR_VM_WRITEBACK_STAT_ITEMS,
1078 };
1079 
1080 static void *vmstat_start(struct seq_file *m, loff_t *pos)
1081 {
1082  unsigned long *v;
1083  int i, stat_items_size;
1084 
1085  if (*pos >= ARRAY_SIZE(vmstat_text))
1086  return NULL;
1087  stat_items_size = NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long) +
1088  NR_VM_WRITEBACK_STAT_ITEMS * sizeof(unsigned long);
1089 
1090 #ifdef CONFIG_VM_EVENT_COUNTERS
1091  stat_items_size += sizeof(struct vm_event_state);
1092 #endif
1093 
1094  v = kmalloc(stat_items_size, GFP_KERNEL);
1095  m->private = v;
1096  if (!v)
1097  return ERR_PTR(-ENOMEM);
1098  for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
1099  v[i] = global_page_state(i);
1100  v += NR_VM_ZONE_STAT_ITEMS;
1101 
1102  global_dirty_limits(v + NR_DIRTY_BG_THRESHOLD,
1103  v + NR_DIRTY_THRESHOLD);
1104  v += NR_VM_WRITEBACK_STAT_ITEMS;
1105 
1106 #ifdef CONFIG_VM_EVENT_COUNTERS
1107  all_vm_events(v);
1108  v[PGPGIN] /= 2; /* sectors -> kbytes */
1109  v[PGPGOUT] /= 2;
1110 #endif
1111  return (unsigned long *)m->private + *pos;
1112 }
1113 
1114 static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)
1115 {
1116  (*pos)++;
1117  if (*pos >= ARRAY_SIZE(vmstat_text))
1118  return NULL;
1119  return (unsigned long *)m->private + *pos;
1120 }
1121 
1122 static int vmstat_show(struct seq_file *m, void *arg)
1123 {
1124  unsigned long *l = arg;
1125  unsigned long off = l - (unsigned long *)m->private;
1126 
1127  seq_printf(m, "%s %lu\n", vmstat_text[off], *l);
1128  return 0;
1129 }
1130 
1131 static void vmstat_stop(struct seq_file *m, void *arg)
1132 {
1133  kfree(m->private);
1134  m->private = NULL;
1135 }
1136 
1137 static const struct seq_operations vmstat_op = {
1138  .start = vmstat_start,
1139  .next = vmstat_next,
1140  .stop = vmstat_stop,
1141  .show = vmstat_show,
1142 };
1143 
1144 static int vmstat_open(struct inode *inode, struct file *file)
1145 {
1146  return seq_open(file, &vmstat_op);
1147 }
1148 
1149 static const struct file_operations proc_vmstat_file_operations = {
1150  .open = vmstat_open,
1151  .read = seq_read,
1152  .llseek = seq_lseek,
1153  .release = seq_release,
1154 };
1155 #endif /* CONFIG_PROC_FS */
1156 
1157 #ifdef CONFIG_SMP
1158 static DEFINE_PER_CPU(struct delayed_work, vmstat_work);
1160 
1161 static void vmstat_update(struct work_struct *w)
1162 {
1163  refresh_cpu_vm_stats(smp_processor_id());
1164  schedule_delayed_work(&__get_cpu_var(vmstat_work),
1165  round_jiffies_relative(sysctl_stat_interval));
1166 }
1167 
1168 static void __cpuinit start_cpu_timer(int cpu)
1169 {
1170  struct delayed_work *work = &per_cpu(vmstat_work, cpu);
1171 
1172  INIT_DEFERRABLE_WORK(work, vmstat_update);
1174 }
1175 
1176 /*
1177  * Use the cpu notifier to insure that the thresholds are recalculated
1178  * when necessary.
1179  */
1180 static int __cpuinit vmstat_cpuup_callback(struct notifier_block *nfb,
1181  unsigned long action,
1182  void *hcpu)
1183 {
1184  long cpu = (long)hcpu;
1185 
1186  switch (action) {
1187  case CPU_ONLINE:
1188  case CPU_ONLINE_FROZEN:
1189  refresh_zone_stat_thresholds();
1190  start_cpu_timer(cpu);
1191  node_set_state(cpu_to_node(cpu), N_CPU);
1192  break;
1193  case CPU_DOWN_PREPARE:
1195  cancel_delayed_work_sync(&per_cpu(vmstat_work, cpu));
1196  per_cpu(vmstat_work, cpu).work.func = NULL;
1197  break;
1198  case CPU_DOWN_FAILED:
1200  start_cpu_timer(cpu);
1201  break;
1202  case CPU_DEAD:
1203  case CPU_DEAD_FROZEN:
1204  refresh_zone_stat_thresholds();
1205  break;
1206  default:
1207  break;
1208  }
1209  return NOTIFY_OK;
1210 }
1211 
1212 static struct notifier_block __cpuinitdata vmstat_notifier =
1213  { &vmstat_cpuup_callback, NULL, 0 };
1214 #endif
1215 
1216 static int __init setup_vmstat(void)
1217 {
1218 #ifdef CONFIG_SMP
1219  int cpu;
1220 
1221  register_cpu_notifier(&vmstat_notifier);
1222 
1223  for_each_online_cpu(cpu)
1224  start_cpu_timer(cpu);
1225 #endif
1226 #ifdef CONFIG_PROC_FS
1227  proc_create("buddyinfo", S_IRUGO, NULL, &fragmentation_file_operations);
1228  proc_create("pagetypeinfo", S_IRUGO, NULL, &pagetypeinfo_file_ops);
1229  proc_create("vmstat", S_IRUGO, NULL, &proc_vmstat_file_operations);
1230  proc_create("zoneinfo", S_IRUGO, NULL, &proc_zoneinfo_file_operations);
1231 #endif
1232  return 0;
1233 }
1234 module_init(setup_vmstat)
1235 
1236 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)
1237 #include <linux/debugfs.h>
1238 
1239 
1240 /*
1241  * Return an index indicating how much of the available free memory is
1242  * unusable for an allocation of the requested size.
1243  */
1244 static int unusable_free_index(unsigned int order,
1245  struct contig_page_info *info)
1246 {
1247  /* No free memory is interpreted as all free memory is unusable */
1248  if (info->free_pages == 0)
1249  return 1000;
1250 
1251  /*
1252  * Index should be a value between 0 and 1. Return a value to 3
1253  * decimal places.
1254  *
1255  * 0 => no fragmentation
1256  * 1 => high fragmentation
1257  */
1258  return div_u64((info->free_pages - (info->free_blocks_suitable << order)) * 1000ULL, info->free_pages);
1259 
1260 }
1261 
1262 static void unusable_show_print(struct seq_file *m,
1263  pg_data_t *pgdat, struct zone *zone)
1264 {
1265  unsigned int order;
1266  int index;
1267  struct contig_page_info info;
1268 
1269  seq_printf(m, "Node %d, zone %8s ",
1270  pgdat->node_id,
1271  zone->name);
1272  for (order = 0; order < MAX_ORDER; ++order) {
1273  fill_contig_page_info(zone, order, &info);
1274  index = unusable_free_index(order, &info);
1275  seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
1276  }
1277 
1278  seq_putc(m, '\n');
1279 }
1280 
1281 /*
1282  * Display unusable free space index
1283  *
1284  * The unusable free space index measures how much of the available free
1285  * memory cannot be used to satisfy an allocation of a given size and is a
1286  * value between 0 and 1. The higher the value, the more of free memory is
1287  * unusable and by implication, the worse the external fragmentation is. This
1288  * can be expressed as a percentage by multiplying by 100.
1289  */
1290 static int unusable_show(struct seq_file *m, void *arg)
1291 {
1292  pg_data_t *pgdat = (pg_data_t *)arg;
1293 
1294  /* check memoryless node */
1295  if (!node_state(pgdat->node_id, N_HIGH_MEMORY))
1296  return 0;
1297 
1298  walk_zones_in_node(m, pgdat, unusable_show_print);
1299 
1300  return 0;
1301 }
1302 
1303 static const struct seq_operations unusable_op = {
1304  .start = frag_start,
1305  .next = frag_next,
1306  .stop = frag_stop,
1307  .show = unusable_show,
1308 };
1309 
1310 static int unusable_open(struct inode *inode, struct file *file)
1311 {
1312  return seq_open(file, &unusable_op);
1313 }
1314 
1315 static const struct file_operations unusable_file_ops = {
1316  .open = unusable_open,
1317  .read = seq_read,
1318  .llseek = seq_lseek,
1319  .release = seq_release,
1320 };
1321 
1322 static void extfrag_show_print(struct seq_file *m,
1323  pg_data_t *pgdat, struct zone *zone)
1324 {
1325  unsigned int order;
1326  int index;
1327 
1328  /* Alloc on stack as interrupts are disabled for zone walk */
1329  struct contig_page_info info;
1330 
1331  seq_printf(m, "Node %d, zone %8s ",
1332  pgdat->node_id,
1333  zone->name);
1334  for (order = 0; order < MAX_ORDER; ++order) {
1335  fill_contig_page_info(zone, order, &info);
1336  index = __fragmentation_index(order, &info);
1337  seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
1338  }
1339 
1340  seq_putc(m, '\n');
1341 }
1342 
1343 /*
1344  * Display fragmentation index for orders that allocations would fail for
1345  */
1346 static int extfrag_show(struct seq_file *m, void *arg)
1347 {
1348  pg_data_t *pgdat = (pg_data_t *)arg;
1349 
1350  walk_zones_in_node(m, pgdat, extfrag_show_print);
1351 
1352  return 0;
1353 }
1354 
1355 static const struct seq_operations extfrag_op = {
1356  .start = frag_start,
1357  .next = frag_next,
1358  .stop = frag_stop,
1359  .show = extfrag_show,
1360 };
1361 
1362 static int extfrag_open(struct inode *inode, struct file *file)
1363 {
1364  return seq_open(file, &extfrag_op);
1365 }
1366 
1367 static const struct file_operations extfrag_file_ops = {
1368  .open = extfrag_open,
1369  .read = seq_read,
1370  .llseek = seq_lseek,
1371  .release = seq_release,
1372 };
1373 
1374 static int __init extfrag_debug_init(void)
1375 {
1376  struct dentry *extfrag_debug_root;
1377 
1378  extfrag_debug_root = debugfs_create_dir("extfrag", NULL);
1379  if (!extfrag_debug_root)
1380  return -ENOMEM;
1381 
1382  if (!debugfs_create_file("unusable_index", 0444,
1383  extfrag_debug_root, NULL, &unusable_file_ops))
1384  goto fail;
1385 
1386  if (!debugfs_create_file("extfrag_index", 0444,
1387  extfrag_debug_root, NULL, &extfrag_file_ops))
1388  goto fail;
1389 
1390  return 0;
1391 fail:
1392  debugfs_remove_recursive(extfrag_debug_root);
1393  return -ENOMEM;
1394 }
1395 
1396 module_init(extfrag_debug_init);
1397 #endif