Merge branch 'for-2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
[linux-2.6.git] / mm / vmstat.c
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  */
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 {
49         get_online_cpus();
50         sum_vm_events(ret);
51         put_online_cpus();
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  */
81 atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS];
82 EXPORT_SYMBOL(vm_stat);
83
84 #ifdef CONFIG_SMP
85
86 static int calculate_threshold(struct zone *zone)
87 {
88         int threshold;
89         int mem;        /* memory in 128 MB units */
90
91         /*
92          * The threshold scales with the number of processors and the amount
93          * of memory per zone. More memory means that we can defer updates for
94          * longer, more processors could lead to more contention.
95          * fls() is used to have a cheap way of logarithmic scaling.
96          *
97          * Some sample thresholds:
98          *
99          * Threshold    Processors      (fls)   Zonesize        fls(mem+1)
100          * ------------------------------------------------------------------
101          * 8            1               1       0.9-1 GB        4
102          * 16           2               2       0.9-1 GB        4
103          * 20           2               2       1-2 GB          5
104          * 24           2               2       2-4 GB          6
105          * 28           2               2       4-8 GB          7
106          * 32           2               2       8-16 GB         8
107          * 4            2               2       <128M           1
108          * 30           4               3       2-4 GB          5
109          * 48           4               3       8-16 GB         8
110          * 32           8               4       1-2 GB          4
111          * 32           8               4       0.9-1GB         4
112          * 10           16              5       <128M           1
113          * 40           16              5       900M            4
114          * 70           64              7       2-4 GB          5
115          * 84           64              7       4-8 GB          6
116          * 108          512             9       4-8 GB          6
117          * 125          1024            10      8-16 GB         8
118          * 125          1024            10      16-32 GB        9
119          */
120
121         mem = zone->present_pages >> (27 - PAGE_SHIFT);
122
123         threshold = 2 * fls(num_online_cpus()) * (1 + fls(mem));
124
125         /*
126          * Maximum threshold is 125
127          */
128         threshold = min(125, threshold);
129
130         return threshold;
131 }
132
133 /*
134  * Refresh the thresholds for each zone.
135  */
136 static void refresh_zone_stat_thresholds(void)
137 {
138         struct zone *zone;
139         int cpu;
140         int threshold;
141
142         for_each_populated_zone(zone) {
143                 unsigned long max_drift, tolerate_drift;
144
145                 threshold = calculate_threshold(zone);
146
147                 for_each_online_cpu(cpu)
148                         per_cpu_ptr(zone->pageset, cpu)->stat_threshold
149                                                         = threshold;
150
151                 /*
152                  * Only set percpu_drift_mark if there is a danger that
153                  * NR_FREE_PAGES reports the low watermark is ok when in fact
154                  * the min watermark could be breached by an allocation
155                  */
156                 tolerate_drift = low_wmark_pages(zone) - min_wmark_pages(zone);
157                 max_drift = num_online_cpus() * threshold;
158                 if (max_drift > tolerate_drift)
159                         zone->percpu_drift_mark = high_wmark_pages(zone) +
160                                         max_drift;
161         }
162 }
163
164 /*
165  * For use when we know that interrupts are disabled.
166  */
167 void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
168                                 int delta)
169 {
170         struct per_cpu_pageset __percpu *pcp = zone->pageset;
171         s8 __percpu *p = pcp->vm_stat_diff + item;
172         long x;
173         long t;
174
175         x = delta + __this_cpu_read(*p);
176
177         t = __this_cpu_read(pcp->stat_threshold);
178
179         if (unlikely(x > t || x < -t)) {
180                 zone_page_state_add(x, zone, item);
181                 x = 0;
182         }
183         __this_cpu_write(*p, x);
184 }
185 EXPORT_SYMBOL(__mod_zone_page_state);
186
187 /*
188  * Optimized increment and decrement functions.
189  *
190  * These are only for a single page and therefore can take a struct page *
191  * argument instead of struct zone *. This allows the inclusion of the code
192  * generated for page_zone(page) into the optimized functions.
193  *
194  * No overflow check is necessary and therefore the differential can be
195  * incremented or decremented in place which may allow the compilers to
196  * generate better code.
197  * The increment or decrement is known and therefore one boundary check can
198  * be omitted.
199  *
200  * NOTE: These functions are very performance sensitive. Change only
201  * with care.
202  *
203  * Some processors have inc/dec instructions that are atomic vs an interrupt.
204  * However, the code must first determine the differential location in a zone
205  * based on the processor number and then inc/dec the counter. There is no
206  * guarantee without disabling preemption that the processor will not change
207  * in between and therefore the atomicity vs. interrupt cannot be exploited
208  * in a useful way here.
209  */
210 void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
211 {
212         struct per_cpu_pageset __percpu *pcp = zone->pageset;
213         s8 __percpu *p = pcp->vm_stat_diff + item;
214         s8 v, t;
215
216         v = __this_cpu_inc_return(*p);
217         t = __this_cpu_read(pcp->stat_threshold);
218         if (unlikely(v > t)) {
219                 s8 overstep = t >> 1;
220
221                 zone_page_state_add(v + overstep, zone, item);
222                 __this_cpu_write(*p, -overstep);
223         }
224 }
225
226 void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
227 {
228         __inc_zone_state(page_zone(page), item);
229 }
230 EXPORT_SYMBOL(__inc_zone_page_state);
231
232 void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
233 {
234         struct per_cpu_pageset __percpu *pcp = zone->pageset;
235         s8 __percpu *p = pcp->vm_stat_diff + item;
236         s8 v, t;
237
238         v = __this_cpu_dec_return(*p);
239         t = __this_cpu_read(pcp->stat_threshold);
240         if (unlikely(v < - t)) {
241                 s8 overstep = t >> 1;
242
243                 zone_page_state_add(v - overstep, zone, item);
244                 __this_cpu_write(*p, overstep);
245         }
246 }
247
248 void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
249 {
250         __dec_zone_state(page_zone(page), item);
251 }
252 EXPORT_SYMBOL(__dec_zone_page_state);
253
254 #ifdef CONFIG_CMPXCHG_LOCAL
255 /*
256  * If we have cmpxchg_local support then we do not need to incur the overhead
257  * that comes with local_irq_save/restore if we use this_cpu_cmpxchg.
258  *
259  * mod_state() modifies the zone counter state through atomic per cpu
260  * operations.
261  *
262  * Overstep mode specifies how overstep should handled:
263  *     0       No overstepping
264  *     1       Overstepping half of threshold
265  *     -1      Overstepping minus half of threshold
266 */
267 static inline void mod_state(struct zone *zone,
268        enum zone_stat_item item, int delta, int overstep_mode)
269 {
270         struct per_cpu_pageset __percpu *pcp = zone->pageset;
271         s8 __percpu *p = pcp->vm_stat_diff + item;
272         long o, n, t, z;
273
274         do {
275                 z = 0;  /* overflow to zone counters */
276
277                 /*
278                  * The fetching of the stat_threshold is racy. We may apply
279                  * a counter threshold to the wrong the cpu if we get
280                  * rescheduled while executing here. However, the following
281                  * will apply the threshold again and therefore bring the
282                  * counter under the threshold.
283                  */
284                 t = this_cpu_read(pcp->stat_threshold);
285
286                 o = this_cpu_read(*p);
287                 n = delta + o;
288
289                 if (n > t || n < -t) {
290                         int os = overstep_mode * (t >> 1) ;
291
292                         /* Overflow must be added to zone counters */
293                         z = n + os;
294                         n = -os;
295                 }
296         } while (this_cpu_cmpxchg(*p, o, n) != o);
297
298         if (z)
299                 zone_page_state_add(z, zone, item);
300 }
301
302 void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
303                                         int delta)
304 {
305         mod_state(zone, item, delta, 0);
306 }
307 EXPORT_SYMBOL(mod_zone_page_state);
308
309 void inc_zone_state(struct zone *zone, enum zone_stat_item item)
310 {
311         mod_state(zone, item, 1, 1);
312 }
313
314 void inc_zone_page_state(struct page *page, enum zone_stat_item item)
315 {
316         mod_state(page_zone(page), item, 1, 1);
317 }
318 EXPORT_SYMBOL(inc_zone_page_state);
319
320 void dec_zone_page_state(struct page *page, enum zone_stat_item item)
321 {
322         mod_state(page_zone(page), item, -1, -1);
323 }
324 EXPORT_SYMBOL(dec_zone_page_state);
325 #else
326 /*
327  * Use interrupt disable to serialize counter updates
328  */
329 void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
330                                         int delta)
331 {
332         unsigned long flags;
333
334         local_irq_save(flags);
335         __mod_zone_page_state(zone, item, delta);
336         local_irq_restore(flags);
337 }
338 EXPORT_SYMBOL(mod_zone_page_state);
339
340 void inc_zone_state(struct zone *zone, enum zone_stat_item item)
341 {
342         unsigned long flags;
343
344         local_irq_save(flags);
345         __inc_zone_state(zone, item);
346         local_irq_restore(flags);
347 }
348
349 void inc_zone_page_state(struct page *page, enum zone_stat_item item)
350 {
351         unsigned long flags;
352         struct zone *zone;
353
354         zone = page_zone(page);
355         local_irq_save(flags);
356         __inc_zone_state(zone, item);
357         local_irq_restore(flags);
358 }
359 EXPORT_SYMBOL(inc_zone_page_state);
360
361 void dec_zone_page_state(struct page *page, enum zone_stat_item item)
362 {
363         unsigned long flags;
364
365         local_irq_save(flags);
366         __dec_zone_page_state(page, item);
367         local_irq_restore(flags);
368 }
369 EXPORT_SYMBOL(dec_zone_page_state);
370 #endif
371
372 /*
373  * Update the zone counters for one cpu.
374  *
375  * The cpu specified must be either the current cpu or a processor that
376  * is not online. If it is the current cpu then the execution thread must
377  * be pinned to the current cpu.
378  *
379  * Note that refresh_cpu_vm_stats strives to only access
380  * node local memory. The per cpu pagesets on remote zones are placed
381  * in the memory local to the processor using that pageset. So the
382  * loop over all zones will access a series of cachelines local to
383  * the processor.
384  *
385  * The call to zone_page_state_add updates the cachelines with the
386  * statistics in the remote zone struct as well as the global cachelines
387  * with the global counters. These could cause remote node cache line
388  * bouncing and will have to be only done when necessary.
389  */
390 void refresh_cpu_vm_stats(int cpu)
391 {
392         struct zone *zone;
393         int i;
394         int global_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
395
396         for_each_populated_zone(zone) {
397                 struct per_cpu_pageset *p;
398
399                 p = per_cpu_ptr(zone->pageset, cpu);
400
401                 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
402                         if (p->vm_stat_diff[i]) {
403                                 unsigned long flags;
404                                 int v;
405
406                                 local_irq_save(flags);
407                                 v = p->vm_stat_diff[i];
408                                 p->vm_stat_diff[i] = 0;
409                                 local_irq_restore(flags);
410                                 atomic_long_add(v, &zone->vm_stat[i]);
411                                 global_diff[i] += v;
412 #ifdef CONFIG_NUMA
413                                 /* 3 seconds idle till flush */
414                                 p->expire = 3;
415 #endif
416                         }
417                 cond_resched();
418 #ifdef CONFIG_NUMA
419                 /*
420                  * Deal with draining the remote pageset of this
421                  * processor
422                  *
423                  * Check if there are pages remaining in this pageset
424                  * if not then there is nothing to expire.
425                  */
426                 if (!p->expire || !p->pcp.count)
427                         continue;
428
429                 /*
430                  * We never drain zones local to this processor.
431                  */
432                 if (zone_to_nid(zone) == numa_node_id()) {
433                         p->expire = 0;
434                         continue;
435                 }
436
437                 p->expire--;
438                 if (p->expire)
439                         continue;
440
441                 if (p->pcp.count)
442                         drain_zone_pages(zone, &p->pcp);
443 #endif
444         }
445
446         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
447                 if (global_diff[i])
448                         atomic_long_add(global_diff[i], &vm_stat[i]);
449 }
450
451 #endif
452
453 #ifdef CONFIG_NUMA
454 /*
455  * zonelist = the list of zones passed to the allocator
456  * z        = the zone from which the allocation occurred.
457  *
458  * Must be called with interrupts disabled.
459  */
460 void zone_statistics(struct zone *preferred_zone, struct zone *z)
461 {
462         if (z->zone_pgdat == preferred_zone->zone_pgdat) {
463                 __inc_zone_state(z, NUMA_HIT);
464         } else {
465                 __inc_zone_state(z, NUMA_MISS);
466                 __inc_zone_state(preferred_zone, NUMA_FOREIGN);
467         }
468         if (z->node == numa_node_id())
469                 __inc_zone_state(z, NUMA_LOCAL);
470         else
471                 __inc_zone_state(z, NUMA_OTHER);
472 }
473 #endif
474
475 #ifdef CONFIG_COMPACTION
476
477 struct contig_page_info {
478         unsigned long free_pages;
479         unsigned long free_blocks_total;
480         unsigned long free_blocks_suitable;
481 };
482
483 /*
484  * Calculate the number of free pages in a zone, how many contiguous
485  * pages are free and how many are large enough to satisfy an allocation of
486  * the target size. Note that this function makes no attempt to estimate
487  * how many suitable free blocks there *might* be if MOVABLE pages were
488  * migrated. Calculating that is possible, but expensive and can be
489  * figured out from userspace
490  */
491 static void fill_contig_page_info(struct zone *zone,
492                                 unsigned int suitable_order,
493                                 struct contig_page_info *info)
494 {
495         unsigned int order;
496
497         info->free_pages = 0;
498         info->free_blocks_total = 0;
499         info->free_blocks_suitable = 0;
500
501         for (order = 0; order < MAX_ORDER; order++) {
502                 unsigned long blocks;
503
504                 /* Count number of free blocks */
505                 blocks = zone->free_area[order].nr_free;
506                 info->free_blocks_total += blocks;
507
508                 /* Count free base pages */
509                 info->free_pages += blocks << order;
510
511                 /* Count the suitable free blocks */
512                 if (order >= suitable_order)
513                         info->free_blocks_suitable += blocks <<
514                                                 (order - suitable_order);
515         }
516 }
517
518 /*
519  * A fragmentation index only makes sense if an allocation of a requested
520  * size would fail. If that is true, the fragmentation index indicates
521  * whether external fragmentation or a lack of memory was the problem.
522  * The value can be used to determine if page reclaim or compaction
523  * should be used
524  */
525 static int __fragmentation_index(unsigned int order, struct contig_page_info *info)
526 {
527         unsigned long requested = 1UL << order;
528
529         if (!info->free_blocks_total)
530                 return 0;
531
532         /* Fragmentation index only makes sense when a request would fail */
533         if (info->free_blocks_suitable)
534                 return -1000;
535
536         /*
537          * Index is between 0 and 1 so return within 3 decimal places
538          *
539          * 0 => allocation would fail due to lack of memory
540          * 1 => allocation would fail due to fragmentation
541          */
542         return 1000 - div_u64( (1000+(div_u64(info->free_pages * 1000ULL, requested))), info->free_blocks_total);
543 }
544
545 /* Same as __fragmentation index but allocs contig_page_info on stack */
546 int fragmentation_index(struct zone *zone, unsigned int order)
547 {
548         struct contig_page_info info;
549
550         fill_contig_page_info(zone, order, &info);
551         return __fragmentation_index(order, &info);
552 }
553 #endif
554
555 #if defined(CONFIG_PROC_FS) || defined(CONFIG_COMPACTION)
556 #include <linux/proc_fs.h>
557 #include <linux/seq_file.h>
558
559 static char * const migratetype_names[MIGRATE_TYPES] = {
560         "Unmovable",
561         "Reclaimable",
562         "Movable",
563         "Reserve",
564         "Isolate",
565 };
566
567 static void *frag_start(struct seq_file *m, loff_t *pos)
568 {
569         pg_data_t *pgdat;
570         loff_t node = *pos;
571         for (pgdat = first_online_pgdat();
572              pgdat && node;
573              pgdat = next_online_pgdat(pgdat))
574                 --node;
575
576         return pgdat;
577 }
578
579 static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
580 {
581         pg_data_t *pgdat = (pg_data_t *)arg;
582
583         (*pos)++;
584         return next_online_pgdat(pgdat);
585 }
586
587 static void frag_stop(struct seq_file *m, void *arg)
588 {
589 }
590
591 /* Walk all the zones in a node and print using a callback */
592 static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat,
593                 void (*print)(struct seq_file *m, pg_data_t *, struct zone *))
594 {
595         struct zone *zone;
596         struct zone *node_zones = pgdat->node_zones;
597         unsigned long flags;
598
599         for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
600                 if (!populated_zone(zone))
601                         continue;
602
603                 spin_lock_irqsave(&zone->lock, flags);
604                 print(m, pgdat, zone);
605                 spin_unlock_irqrestore(&zone->lock, flags);
606         }
607 }
608 #endif
609
610 #ifdef CONFIG_PROC_FS
611 static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,
612                                                 struct zone *zone)
613 {
614         int order;
615
616         seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
617         for (order = 0; order < MAX_ORDER; ++order)
618                 seq_printf(m, "%6lu ", zone->free_area[order].nr_free);
619         seq_putc(m, '\n');
620 }
621
622 /*
623  * This walks the free areas for each zone.
624  */
625 static int frag_show(struct seq_file *m, void *arg)
626 {
627         pg_data_t *pgdat = (pg_data_t *)arg;
628         walk_zones_in_node(m, pgdat, frag_show_print);
629         return 0;
630 }
631
632 static void pagetypeinfo_showfree_print(struct seq_file *m,
633                                         pg_data_t *pgdat, struct zone *zone)
634 {
635         int order, mtype;
636
637         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++) {
638                 seq_printf(m, "Node %4d, zone %8s, type %12s ",
639                                         pgdat->node_id,
640                                         zone->name,
641                                         migratetype_names[mtype]);
642                 for (order = 0; order < MAX_ORDER; ++order) {
643                         unsigned long freecount = 0;
644                         struct free_area *area;
645                         struct list_head *curr;
646
647                         area = &(zone->free_area[order]);
648
649                         list_for_each(curr, &area->free_list[mtype])
650                                 freecount++;
651                         seq_printf(m, "%6lu ", freecount);
652                 }
653                 seq_putc(m, '\n');
654         }
655 }
656
657 /* Print out the free pages at each order for each migatetype */
658 static int pagetypeinfo_showfree(struct seq_file *m, void *arg)
659 {
660         int order;
661         pg_data_t *pgdat = (pg_data_t *)arg;
662
663         /* Print header */
664         seq_printf(m, "%-43s ", "Free pages count per migrate type at order");
665         for (order = 0; order < MAX_ORDER; ++order)
666                 seq_printf(m, "%6d ", order);
667         seq_putc(m, '\n');
668
669         walk_zones_in_node(m, pgdat, pagetypeinfo_showfree_print);
670
671         return 0;
672 }
673
674 static void pagetypeinfo_showblockcount_print(struct seq_file *m,
675                                         pg_data_t *pgdat, struct zone *zone)
676 {
677         int mtype;
678         unsigned long pfn;
679         unsigned long start_pfn = zone->zone_start_pfn;
680         unsigned long end_pfn = start_pfn + zone->spanned_pages;
681         unsigned long count[MIGRATE_TYPES] = { 0, };
682
683         for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
684                 struct page *page;
685
686                 if (!pfn_valid(pfn))
687                         continue;
688
689                 page = pfn_to_page(pfn);
690
691                 /* Watch for unexpected holes punched in the memmap */
692                 if (!memmap_valid_within(pfn, page, zone))
693                         continue;
694
695                 mtype = get_pageblock_migratetype(page);
696
697                 if (mtype < MIGRATE_TYPES)
698                         count[mtype]++;
699         }
700
701         /* Print counts */
702         seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
703         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
704                 seq_printf(m, "%12lu ", count[mtype]);
705         seq_putc(m, '\n');
706 }
707
708 /* Print out the free pages at each order for each migratetype */
709 static int pagetypeinfo_showblockcount(struct seq_file *m, void *arg)
710 {
711         int mtype;
712         pg_data_t *pgdat = (pg_data_t *)arg;
713
714         seq_printf(m, "\n%-23s", "Number of blocks type ");
715         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
716                 seq_printf(m, "%12s ", migratetype_names[mtype]);
717         seq_putc(m, '\n');
718         walk_zones_in_node(m, pgdat, pagetypeinfo_showblockcount_print);
719
720         return 0;
721 }
722
723 /*
724  * This prints out statistics in relation to grouping pages by mobility.
725  * It is expensive to collect so do not constantly read the file.
726  */
727 static int pagetypeinfo_show(struct seq_file *m, void *arg)
728 {
729         pg_data_t *pgdat = (pg_data_t *)arg;
730
731         /* check memoryless node */
732         if (!node_state(pgdat->node_id, N_HIGH_MEMORY))
733                 return 0;
734
735         seq_printf(m, "Page block order: %d\n", pageblock_order);
736         seq_printf(m, "Pages per block:  %lu\n", pageblock_nr_pages);
737         seq_putc(m, '\n');
738         pagetypeinfo_showfree(m, pgdat);
739         pagetypeinfo_showblockcount(m, pgdat);
740
741         return 0;
742 }
743
744 static const struct seq_operations fragmentation_op = {
745         .start  = frag_start,
746         .next   = frag_next,
747         .stop   = frag_stop,
748         .show   = frag_show,
749 };
750
751 static int fragmentation_open(struct inode *inode, struct file *file)
752 {
753         return seq_open(file, &fragmentation_op);
754 }
755
756 static const struct file_operations fragmentation_file_operations = {
757         .open           = fragmentation_open,
758         .read           = seq_read,
759         .llseek         = seq_lseek,
760         .release        = seq_release,
761 };
762
763 static const struct seq_operations pagetypeinfo_op = {
764         .start  = frag_start,
765         .next   = frag_next,
766         .stop   = frag_stop,
767         .show   = pagetypeinfo_show,
768 };
769
770 static int pagetypeinfo_open(struct inode *inode, struct file *file)
771 {
772         return seq_open(file, &pagetypeinfo_op);
773 }
774
775 static const struct file_operations pagetypeinfo_file_ops = {
776         .open           = pagetypeinfo_open,
777         .read           = seq_read,
778         .llseek         = seq_lseek,
779         .release        = seq_release,
780 };
781
782 #ifdef CONFIG_ZONE_DMA
783 #define TEXT_FOR_DMA(xx) xx "_dma",
784 #else
785 #define TEXT_FOR_DMA(xx)
786 #endif
787
788 #ifdef CONFIG_ZONE_DMA32
789 #define TEXT_FOR_DMA32(xx) xx "_dma32",
790 #else
791 #define TEXT_FOR_DMA32(xx)
792 #endif
793
794 #ifdef CONFIG_HIGHMEM
795 #define TEXT_FOR_HIGHMEM(xx) xx "_high",
796 #else
797 #define TEXT_FOR_HIGHMEM(xx)
798 #endif
799
800 #define TEXTS_FOR_ZONES(xx) TEXT_FOR_DMA(xx) TEXT_FOR_DMA32(xx) xx "_normal", \
801                                         TEXT_FOR_HIGHMEM(xx) xx "_movable",
802
803 static const char * const vmstat_text[] = {
804         /* Zoned VM counters */
805         "nr_free_pages",
806         "nr_inactive_anon",
807         "nr_active_anon",
808         "nr_inactive_file",
809         "nr_active_file",
810         "nr_unevictable",
811         "nr_mlock",
812         "nr_anon_pages",
813         "nr_mapped",
814         "nr_file_pages",
815         "nr_dirty",
816         "nr_writeback",
817         "nr_slab_reclaimable",
818         "nr_slab_unreclaimable",
819         "nr_page_table_pages",
820         "nr_kernel_stack",
821         "nr_unstable",
822         "nr_bounce",
823         "nr_vmscan_write",
824         "nr_writeback_temp",
825         "nr_isolated_anon",
826         "nr_isolated_file",
827         "nr_shmem",
828         "nr_dirtied",
829         "nr_written",
830
831 #ifdef CONFIG_NUMA
832         "numa_hit",
833         "numa_miss",
834         "numa_foreign",
835         "numa_interleave",
836         "numa_local",
837         "numa_other",
838 #endif
839         "nr_dirty_threshold",
840         "nr_dirty_background_threshold",
841
842 #ifdef CONFIG_VM_EVENT_COUNTERS
843         "pgpgin",
844         "pgpgout",
845         "pswpin",
846         "pswpout",
847
848         TEXTS_FOR_ZONES("pgalloc")
849
850         "pgfree",
851         "pgactivate",
852         "pgdeactivate",
853
854         "pgfault",
855         "pgmajfault",
856
857         TEXTS_FOR_ZONES("pgrefill")
858         TEXTS_FOR_ZONES("pgsteal")
859         TEXTS_FOR_ZONES("pgscan_kswapd")
860         TEXTS_FOR_ZONES("pgscan_direct")
861
862 #ifdef CONFIG_NUMA
863         "zone_reclaim_failed",
864 #endif
865         "pginodesteal",
866         "slabs_scanned",
867         "kswapd_steal",
868         "kswapd_inodesteal",
869         "kswapd_low_wmark_hit_quickly",
870         "kswapd_high_wmark_hit_quickly",
871         "kswapd_skip_congestion_wait",
872         "pageoutrun",
873         "allocstall",
874
875         "pgrotated",
876
877 #ifdef CONFIG_COMPACTION
878         "compact_blocks_moved",
879         "compact_pages_moved",
880         "compact_pagemigrate_failed",
881         "compact_stall",
882         "compact_fail",
883         "compact_success",
884 #endif
885
886 #ifdef CONFIG_HUGETLB_PAGE
887         "htlb_buddy_alloc_success",
888         "htlb_buddy_alloc_fail",
889 #endif
890         "unevictable_pgs_culled",
891         "unevictable_pgs_scanned",
892         "unevictable_pgs_rescued",
893         "unevictable_pgs_mlocked",
894         "unevictable_pgs_munlocked",
895         "unevictable_pgs_cleared",
896         "unevictable_pgs_stranded",
897         "unevictable_pgs_mlockfreed",
898 #endif
899 };
900
901 static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
902                                                         struct zone *zone)
903 {
904         int i;
905         seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name);
906         seq_printf(m,
907                    "\n  pages free     %lu"
908                    "\n        min      %lu"
909                    "\n        low      %lu"
910                    "\n        high     %lu"
911                    "\n        scanned  %lu"
912                    "\n        spanned  %lu"
913                    "\n        present  %lu",
914                    zone_nr_free_pages(zone),
915                    min_wmark_pages(zone),
916                    low_wmark_pages(zone),
917                    high_wmark_pages(zone),
918                    zone->pages_scanned,
919                    zone->spanned_pages,
920                    zone->present_pages);
921
922         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
923                 seq_printf(m, "\n    %-12s %lu", vmstat_text[i],
924                                 zone_page_state(zone, i));
925
926         seq_printf(m,
927                    "\n        protection: (%lu",
928                    zone->lowmem_reserve[0]);
929         for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++)
930                 seq_printf(m, ", %lu", zone->lowmem_reserve[i]);
931         seq_printf(m,
932                    ")"
933                    "\n  pagesets");
934         for_each_online_cpu(i) {
935                 struct per_cpu_pageset *pageset;
936
937                 pageset = per_cpu_ptr(zone->pageset, i);
938                 seq_printf(m,
939                            "\n    cpu: %i"
940                            "\n              count: %i"
941                            "\n              high:  %i"
942                            "\n              batch: %i",
943                            i,
944                            pageset->pcp.count,
945                            pageset->pcp.high,
946                            pageset->pcp.batch);
947 #ifdef CONFIG_SMP
948                 seq_printf(m, "\n  vm stats threshold: %d",
949                                 pageset->stat_threshold);
950 #endif
951         }
952         seq_printf(m,
953                    "\n  all_unreclaimable: %u"
954                    "\n  start_pfn:         %lu"
955                    "\n  inactive_ratio:    %u",
956                    zone->all_unreclaimable,
957                    zone->zone_start_pfn,
958                    zone->inactive_ratio);
959         seq_putc(m, '\n');
960 }
961
962 /*
963  * Output information about zones in @pgdat.
964  */
965 static int zoneinfo_show(struct seq_file *m, void *arg)
966 {
967         pg_data_t *pgdat = (pg_data_t *)arg;
968         walk_zones_in_node(m, pgdat, zoneinfo_show_print);
969         return 0;
970 }
971
972 static const struct seq_operations zoneinfo_op = {
973         .start  = frag_start, /* iterate over all zones. The same as in
974                                * fragmentation. */
975         .next   = frag_next,
976         .stop   = frag_stop,
977         .show   = zoneinfo_show,
978 };
979
980 static int zoneinfo_open(struct inode *inode, struct file *file)
981 {
982         return seq_open(file, &zoneinfo_op);
983 }
984
985 static const struct file_operations proc_zoneinfo_file_operations = {
986         .open           = zoneinfo_open,
987         .read           = seq_read,
988         .llseek         = seq_lseek,
989         .release        = seq_release,
990 };
991
992 enum writeback_stat_item {
993         NR_DIRTY_THRESHOLD,
994         NR_DIRTY_BG_THRESHOLD,
995         NR_VM_WRITEBACK_STAT_ITEMS,
996 };
997
998 static void *vmstat_start(struct seq_file *m, loff_t *pos)
999 {
1000         unsigned long *v;
1001         int i, stat_items_size;
1002
1003         if (*pos >= ARRAY_SIZE(vmstat_text))
1004                 return NULL;
1005         stat_items_size = NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long) +
1006                           NR_VM_WRITEBACK_STAT_ITEMS * sizeof(unsigned long);
1007
1008 #ifdef CONFIG_VM_EVENT_COUNTERS
1009         stat_items_size += sizeof(struct vm_event_state);
1010 #endif
1011
1012         v = kmalloc(stat_items_size, GFP_KERNEL);
1013         m->private = v;
1014         if (!v)
1015                 return ERR_PTR(-ENOMEM);
1016         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
1017                 v[i] = global_page_state(i);
1018         v += NR_VM_ZONE_STAT_ITEMS;
1019
1020         global_dirty_limits(v + NR_DIRTY_BG_THRESHOLD,
1021                             v + NR_DIRTY_THRESHOLD);
1022         v += NR_VM_WRITEBACK_STAT_ITEMS;
1023
1024 #ifdef CONFIG_VM_EVENT_COUNTERS
1025         all_vm_events(v);
1026         v[PGPGIN] /= 2;         /* sectors -> kbytes */
1027         v[PGPGOUT] /= 2;
1028 #endif
1029         return (unsigned long *)m->private + *pos;
1030 }
1031
1032 static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)
1033 {
1034         (*pos)++;
1035         if (*pos >= ARRAY_SIZE(vmstat_text))
1036                 return NULL;
1037         return (unsigned long *)m->private + *pos;
1038 }
1039
1040 static int vmstat_show(struct seq_file *m, void *arg)
1041 {
1042         unsigned long *l = arg;
1043         unsigned long off = l - (unsigned long *)m->private;
1044
1045         seq_printf(m, "%s %lu\n", vmstat_text[off], *l);
1046         return 0;
1047 }
1048
1049 static void vmstat_stop(struct seq_file *m, void *arg)
1050 {
1051         kfree(m->private);
1052         m->private = NULL;
1053 }
1054
1055 static const struct seq_operations vmstat_op = {
1056         .start  = vmstat_start,
1057         .next   = vmstat_next,
1058         .stop   = vmstat_stop,
1059         .show   = vmstat_show,
1060 };
1061
1062 static int vmstat_open(struct inode *inode, struct file *file)
1063 {
1064         return seq_open(file, &vmstat_op);
1065 }
1066
1067 static const struct file_operations proc_vmstat_file_operations = {
1068         .open           = vmstat_open,
1069         .read           = seq_read,
1070         .llseek         = seq_lseek,
1071         .release        = seq_release,
1072 };
1073 #endif /* CONFIG_PROC_FS */
1074
1075 #ifdef CONFIG_SMP
1076 static DEFINE_PER_CPU(struct delayed_work, vmstat_work);
1077 int sysctl_stat_interval __read_mostly = HZ;
1078
1079 static void vmstat_update(struct work_struct *w)
1080 {
1081         refresh_cpu_vm_stats(smp_processor_id());
1082         schedule_delayed_work(&__get_cpu_var(vmstat_work),
1083                 round_jiffies_relative(sysctl_stat_interval));
1084 }
1085
1086 static void __cpuinit start_cpu_timer(int cpu)
1087 {
1088         struct delayed_work *work = &per_cpu(vmstat_work, cpu);
1089
1090         INIT_DELAYED_WORK_DEFERRABLE(work, vmstat_update);
1091         schedule_delayed_work_on(cpu, work, __round_jiffies_relative(HZ, cpu));
1092 }
1093
1094 /*
1095  * Use the cpu notifier to insure that the thresholds are recalculated
1096  * when necessary.
1097  */
1098 static int __cpuinit vmstat_cpuup_callback(struct notifier_block *nfb,
1099                 unsigned long action,
1100                 void *hcpu)
1101 {
1102         long cpu = (long)hcpu;
1103
1104         switch (action) {
1105         case CPU_ONLINE:
1106         case CPU_ONLINE_FROZEN:
1107                 refresh_zone_stat_thresholds();
1108                 start_cpu_timer(cpu);
1109                 node_set_state(cpu_to_node(cpu), N_CPU);
1110                 break;
1111         case CPU_DOWN_PREPARE:
1112         case CPU_DOWN_PREPARE_FROZEN:
1113                 cancel_delayed_work_sync(&per_cpu(vmstat_work, cpu));
1114                 per_cpu(vmstat_work, cpu).work.func = NULL;
1115                 break;
1116         case CPU_DOWN_FAILED:
1117         case CPU_DOWN_FAILED_FROZEN:
1118                 start_cpu_timer(cpu);
1119                 break;
1120         case CPU_DEAD:
1121         case CPU_DEAD_FROZEN:
1122                 refresh_zone_stat_thresholds();
1123                 break;
1124         default:
1125                 break;
1126         }
1127         return NOTIFY_OK;
1128 }
1129
1130 static struct notifier_block __cpuinitdata vmstat_notifier =
1131         { &vmstat_cpuup_callback, NULL, 0 };
1132 #endif
1133
1134 static int __init setup_vmstat(void)
1135 {
1136 #ifdef CONFIG_SMP
1137         int cpu;
1138
1139         refresh_zone_stat_thresholds();
1140         register_cpu_notifier(&vmstat_notifier);
1141
1142         for_each_online_cpu(cpu)
1143                 start_cpu_timer(cpu);
1144 #endif
1145 #ifdef CONFIG_PROC_FS
1146         proc_create("buddyinfo", S_IRUGO, NULL, &fragmentation_file_operations);
1147         proc_create("pagetypeinfo", S_IRUGO, NULL, &pagetypeinfo_file_ops);
1148         proc_create("vmstat", S_IRUGO, NULL, &proc_vmstat_file_operations);
1149         proc_create("zoneinfo", S_IRUGO, NULL, &proc_zoneinfo_file_operations);
1150 #endif
1151         return 0;
1152 }
1153 module_init(setup_vmstat)
1154
1155 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)
1156 #include <linux/debugfs.h>
1157
1158 static struct dentry *extfrag_debug_root;
1159
1160 /*
1161  * Return an index indicating how much of the available free memory is
1162  * unusable for an allocation of the requested size.
1163  */
1164 static int unusable_free_index(unsigned int order,
1165                                 struct contig_page_info *info)
1166 {
1167         /* No free memory is interpreted as all free memory is unusable */
1168         if (info->free_pages == 0)
1169                 return 1000;
1170
1171         /*
1172          * Index should be a value between 0 and 1. Return a value to 3
1173          * decimal places.
1174          *
1175          * 0 => no fragmentation
1176          * 1 => high fragmentation
1177          */
1178         return div_u64((info->free_pages - (info->free_blocks_suitable << order)) * 1000ULL, info->free_pages);
1179
1180 }
1181
1182 static void unusable_show_print(struct seq_file *m,
1183                                         pg_data_t *pgdat, struct zone *zone)
1184 {
1185         unsigned int order;
1186         int index;
1187         struct contig_page_info info;
1188
1189         seq_printf(m, "Node %d, zone %8s ",
1190                                 pgdat->node_id,
1191                                 zone->name);
1192         for (order = 0; order < MAX_ORDER; ++order) {
1193                 fill_contig_page_info(zone, order, &info);
1194                 index = unusable_free_index(order, &info);
1195                 seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
1196         }
1197
1198         seq_putc(m, '\n');
1199 }
1200
1201 /*
1202  * Display unusable free space index
1203  *
1204  * The unusable free space index measures how much of the available free
1205  * memory cannot be used to satisfy an allocation of a given size and is a
1206  * value between 0 and 1. The higher the value, the more of free memory is
1207  * unusable and by implication, the worse the external fragmentation is. This
1208  * can be expressed as a percentage by multiplying by 100.
1209  */
1210 static int unusable_show(struct seq_file *m, void *arg)
1211 {
1212         pg_data_t *pgdat = (pg_data_t *)arg;
1213
1214         /* check memoryless node */
1215         if (!node_state(pgdat->node_id, N_HIGH_MEMORY))
1216                 return 0;
1217
1218         walk_zones_in_node(m, pgdat, unusable_show_print);
1219
1220         return 0;
1221 }
1222
1223 static const struct seq_operations unusable_op = {
1224         .start  = frag_start,
1225         .next   = frag_next,
1226         .stop   = frag_stop,
1227         .show   = unusable_show,
1228 };
1229
1230 static int unusable_open(struct inode *inode, struct file *file)
1231 {
1232         return seq_open(file, &unusable_op);
1233 }
1234
1235 static const struct file_operations unusable_file_ops = {
1236         .open           = unusable_open,
1237         .read           = seq_read,
1238         .llseek         = seq_lseek,
1239         .release        = seq_release,
1240 };
1241
1242 static void extfrag_show_print(struct seq_file *m,
1243                                         pg_data_t *pgdat, struct zone *zone)
1244 {
1245         unsigned int order;
1246         int index;
1247
1248         /* Alloc on stack as interrupts are disabled for zone walk */
1249         struct contig_page_info info;
1250
1251         seq_printf(m, "Node %d, zone %8s ",
1252                                 pgdat->node_id,
1253                                 zone->name);
1254         for (order = 0; order < MAX_ORDER; ++order) {
1255                 fill_contig_page_info(zone, order, &info);
1256                 index = __fragmentation_index(order, &info);
1257                 seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
1258         }
1259
1260         seq_putc(m, '\n');
1261 }
1262
1263 /*
1264  * Display fragmentation index for orders that allocations would fail for
1265  */
1266 static int extfrag_show(struct seq_file *m, void *arg)
1267 {
1268         pg_data_t *pgdat = (pg_data_t *)arg;
1269
1270         walk_zones_in_node(m, pgdat, extfrag_show_print);
1271
1272         return 0;
1273 }
1274
1275 static const struct seq_operations extfrag_op = {
1276         .start  = frag_start,
1277         .next   = frag_next,
1278         .stop   = frag_stop,
1279         .show   = extfrag_show,
1280 };
1281
1282 static int extfrag_open(struct inode *inode, struct file *file)
1283 {
1284         return seq_open(file, &extfrag_op);
1285 }
1286
1287 static const struct file_operations extfrag_file_ops = {
1288         .open           = extfrag_open,
1289         .read           = seq_read,
1290         .llseek         = seq_lseek,
1291         .release        = seq_release,
1292 };
1293
1294 static int __init extfrag_debug_init(void)
1295 {
1296         extfrag_debug_root = debugfs_create_dir("extfrag", NULL);
1297         if (!extfrag_debug_root)
1298                 return -ENOMEM;
1299
1300         if (!debugfs_create_file("unusable_index", 0444,
1301                         extfrag_debug_root, NULL, &unusable_file_ops))
1302                 return -ENOMEM;
1303
1304         if (!debugfs_create_file("extfrag_index", 0444,
1305                         extfrag_debug_root, NULL, &extfrag_file_ops))
1306                 return -ENOMEM;
1307
1308         return 0;
1309 }
1310
1311 module_init(extfrag_debug_init);
1312 #endif