vmscan: Use an indexed array for LRU variables
[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
12 #include <linux/mm.h>
13 #include <linux/err.h>
14 #include <linux/module.h>
15 #include <linux/cpu.h>
16 #include <linux/vmstat.h>
17 #include <linux/sched.h>
18
19 #ifdef CONFIG_VM_EVENT_COUNTERS
20 DEFINE_PER_CPU(struct vm_event_state, vm_event_states) = {{0}};
21 EXPORT_PER_CPU_SYMBOL(vm_event_states);
22
23 static void sum_vm_events(unsigned long *ret, cpumask_t *cpumask)
24 {
25         int cpu;
26         int i;
27
28         memset(ret, 0, NR_VM_EVENT_ITEMS * sizeof(unsigned long));
29
30         for_each_cpu_mask_nr(cpu, *cpumask) {
31                 struct vm_event_state *this = &per_cpu(vm_event_states, cpu);
32
33                 for (i = 0; i < NR_VM_EVENT_ITEMS; i++)
34                         ret[i] += this->event[i];
35         }
36 }
37
38 /*
39  * Accumulate the vm event counters across all CPUs.
40  * The result is unavoidably approximate - it can change
41  * during and after execution of this function.
42 */
43 void all_vm_events(unsigned long *ret)
44 {
45         get_online_cpus();
46         sum_vm_events(ret, &cpu_online_map);
47         put_online_cpus();
48 }
49 EXPORT_SYMBOL_GPL(all_vm_events);
50
51 #ifdef CONFIG_HOTPLUG
52 /*
53  * Fold the foreign cpu events into our own.
54  *
55  * This is adding to the events on one processor
56  * but keeps the global counts constant.
57  */
58 void vm_events_fold_cpu(int cpu)
59 {
60         struct vm_event_state *fold_state = &per_cpu(vm_event_states, cpu);
61         int i;
62
63         for (i = 0; i < NR_VM_EVENT_ITEMS; i++) {
64                 count_vm_events(i, fold_state->event[i]);
65                 fold_state->event[i] = 0;
66         }
67 }
68 #endif /* CONFIG_HOTPLUG */
69
70 #endif /* CONFIG_VM_EVENT_COUNTERS */
71
72 /*
73  * Manage combined zone based / global counters
74  *
75  * vm_stat contains the global counters
76  */
77 atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS];
78 EXPORT_SYMBOL(vm_stat);
79
80 #ifdef CONFIG_SMP
81
82 static int calculate_threshold(struct zone *zone)
83 {
84         int threshold;
85         int mem;        /* memory in 128 MB units */
86
87         /*
88          * The threshold scales with the number of processors and the amount
89          * of memory per zone. More memory means that we can defer updates for
90          * longer, more processors could lead to more contention.
91          * fls() is used to have a cheap way of logarithmic scaling.
92          *
93          * Some sample thresholds:
94          *
95          * Threshold    Processors      (fls)   Zonesize        fls(mem+1)
96          * ------------------------------------------------------------------
97          * 8            1               1       0.9-1 GB        4
98          * 16           2               2       0.9-1 GB        4
99          * 20           2               2       1-2 GB          5
100          * 24           2               2       2-4 GB          6
101          * 28           2               2       4-8 GB          7
102          * 32           2               2       8-16 GB         8
103          * 4            2               2       <128M           1
104          * 30           4               3       2-4 GB          5
105          * 48           4               3       8-16 GB         8
106          * 32           8               4       1-2 GB          4
107          * 32           8               4       0.9-1GB         4
108          * 10           16              5       <128M           1
109          * 40           16              5       900M            4
110          * 70           64              7       2-4 GB          5
111          * 84           64              7       4-8 GB          6
112          * 108          512             9       4-8 GB          6
113          * 125          1024            10      8-16 GB         8
114          * 125          1024            10      16-32 GB        9
115          */
116
117         mem = zone->present_pages >> (27 - PAGE_SHIFT);
118
119         threshold = 2 * fls(num_online_cpus()) * (1 + fls(mem));
120
121         /*
122          * Maximum threshold is 125
123          */
124         threshold = min(125, threshold);
125
126         return threshold;
127 }
128
129 /*
130  * Refresh the thresholds for each zone.
131  */
132 static void refresh_zone_stat_thresholds(void)
133 {
134         struct zone *zone;
135         int cpu;
136         int threshold;
137
138         for_each_zone(zone) {
139
140                 if (!zone->present_pages)
141                         continue;
142
143                 threshold = calculate_threshold(zone);
144
145                 for_each_online_cpu(cpu)
146                         zone_pcp(zone, cpu)->stat_threshold = threshold;
147         }
148 }
149
150 /*
151  * For use when we know that interrupts are disabled.
152  */
153 void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
154                                 int delta)
155 {
156         struct per_cpu_pageset *pcp = zone_pcp(zone, smp_processor_id());
157         s8 *p = pcp->vm_stat_diff + item;
158         long x;
159
160         x = delta + *p;
161
162         if (unlikely(x > pcp->stat_threshold || x < -pcp->stat_threshold)) {
163                 zone_page_state_add(x, zone, item);
164                 x = 0;
165         }
166         *p = x;
167 }
168 EXPORT_SYMBOL(__mod_zone_page_state);
169
170 /*
171  * For an unknown interrupt state
172  */
173 void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
174                                         int delta)
175 {
176         unsigned long flags;
177
178         local_irq_save(flags);
179         __mod_zone_page_state(zone, item, delta);
180         local_irq_restore(flags);
181 }
182 EXPORT_SYMBOL(mod_zone_page_state);
183
184 /*
185  * Optimized increment and decrement functions.
186  *
187  * These are only for a single page and therefore can take a struct page *
188  * argument instead of struct zone *. This allows the inclusion of the code
189  * generated for page_zone(page) into the optimized functions.
190  *
191  * No overflow check is necessary and therefore the differential can be
192  * incremented or decremented in place which may allow the compilers to
193  * generate better code.
194  * The increment or decrement is known and therefore one boundary check can
195  * be omitted.
196  *
197  * NOTE: These functions are very performance sensitive. Change only
198  * with care.
199  *
200  * Some processors have inc/dec instructions that are atomic vs an interrupt.
201  * However, the code must first determine the differential location in a zone
202  * based on the processor number and then inc/dec the counter. There is no
203  * guarantee without disabling preemption that the processor will not change
204  * in between and therefore the atomicity vs. interrupt cannot be exploited
205  * in a useful way here.
206  */
207 void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
208 {
209         struct per_cpu_pageset *pcp = zone_pcp(zone, smp_processor_id());
210         s8 *p = pcp->vm_stat_diff + item;
211
212         (*p)++;
213
214         if (unlikely(*p > pcp->stat_threshold)) {
215                 int overstep = pcp->stat_threshold / 2;
216
217                 zone_page_state_add(*p + overstep, zone, item);
218                 *p = -overstep;
219         }
220 }
221
222 void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
223 {
224         __inc_zone_state(page_zone(page), item);
225 }
226 EXPORT_SYMBOL(__inc_zone_page_state);
227
228 void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
229 {
230         struct per_cpu_pageset *pcp = zone_pcp(zone, smp_processor_id());
231         s8 *p = pcp->vm_stat_diff + item;
232
233         (*p)--;
234
235         if (unlikely(*p < - pcp->stat_threshold)) {
236                 int overstep = pcp->stat_threshold / 2;
237
238                 zone_page_state_add(*p - overstep, zone, item);
239                 *p = overstep;
240         }
241 }
242
243 void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
244 {
245         __dec_zone_state(page_zone(page), item);
246 }
247 EXPORT_SYMBOL(__dec_zone_page_state);
248
249 void inc_zone_state(struct zone *zone, enum zone_stat_item item)
250 {
251         unsigned long flags;
252
253         local_irq_save(flags);
254         __inc_zone_state(zone, item);
255         local_irq_restore(flags);
256 }
257
258 void inc_zone_page_state(struct page *page, enum zone_stat_item item)
259 {
260         unsigned long flags;
261         struct zone *zone;
262
263         zone = page_zone(page);
264         local_irq_save(flags);
265         __inc_zone_state(zone, item);
266         local_irq_restore(flags);
267 }
268 EXPORT_SYMBOL(inc_zone_page_state);
269
270 void dec_zone_page_state(struct page *page, enum zone_stat_item item)
271 {
272         unsigned long flags;
273
274         local_irq_save(flags);
275         __dec_zone_page_state(page, item);
276         local_irq_restore(flags);
277 }
278 EXPORT_SYMBOL(dec_zone_page_state);
279
280 /*
281  * Update the zone counters for one cpu.
282  *
283  * The cpu specified must be either the current cpu or a processor that
284  * is not online. If it is the current cpu then the execution thread must
285  * be pinned to the current cpu.
286  *
287  * Note that refresh_cpu_vm_stats strives to only access
288  * node local memory. The per cpu pagesets on remote zones are placed
289  * in the memory local to the processor using that pageset. So the
290  * loop over all zones will access a series of cachelines local to
291  * the processor.
292  *
293  * The call to zone_page_state_add updates the cachelines with the
294  * statistics in the remote zone struct as well as the global cachelines
295  * with the global counters. These could cause remote node cache line
296  * bouncing and will have to be only done when necessary.
297  */
298 void refresh_cpu_vm_stats(int cpu)
299 {
300         struct zone *zone;
301         int i;
302         int global_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
303
304         for_each_zone(zone) {
305                 struct per_cpu_pageset *p;
306
307                 if (!populated_zone(zone))
308                         continue;
309
310                 p = zone_pcp(zone, cpu);
311
312                 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
313                         if (p->vm_stat_diff[i]) {
314                                 unsigned long flags;
315                                 int v;
316
317                                 local_irq_save(flags);
318                                 v = p->vm_stat_diff[i];
319                                 p->vm_stat_diff[i] = 0;
320                                 local_irq_restore(flags);
321                                 atomic_long_add(v, &zone->vm_stat[i]);
322                                 global_diff[i] += v;
323 #ifdef CONFIG_NUMA
324                                 /* 3 seconds idle till flush */
325                                 p->expire = 3;
326 #endif
327                         }
328                 cond_resched();
329 #ifdef CONFIG_NUMA
330                 /*
331                  * Deal with draining the remote pageset of this
332                  * processor
333                  *
334                  * Check if there are pages remaining in this pageset
335                  * if not then there is nothing to expire.
336                  */
337                 if (!p->expire || !p->pcp.count)
338                         continue;
339
340                 /*
341                  * We never drain zones local to this processor.
342                  */
343                 if (zone_to_nid(zone) == numa_node_id()) {
344                         p->expire = 0;
345                         continue;
346                 }
347
348                 p->expire--;
349                 if (p->expire)
350                         continue;
351
352                 if (p->pcp.count)
353                         drain_zone_pages(zone, &p->pcp);
354 #endif
355         }
356
357         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
358                 if (global_diff[i])
359                         atomic_long_add(global_diff[i], &vm_stat[i]);
360 }
361
362 #endif
363
364 #ifdef CONFIG_NUMA
365 /*
366  * zonelist = the list of zones passed to the allocator
367  * z        = the zone from which the allocation occurred.
368  *
369  * Must be called with interrupts disabled.
370  */
371 void zone_statistics(struct zone *preferred_zone, struct zone *z)
372 {
373         if (z->zone_pgdat == preferred_zone->zone_pgdat) {
374                 __inc_zone_state(z, NUMA_HIT);
375         } else {
376                 __inc_zone_state(z, NUMA_MISS);
377                 __inc_zone_state(preferred_zone, NUMA_FOREIGN);
378         }
379         if (z->node == numa_node_id())
380                 __inc_zone_state(z, NUMA_LOCAL);
381         else
382                 __inc_zone_state(z, NUMA_OTHER);
383 }
384 #endif
385
386 #ifdef CONFIG_PROC_FS
387
388 #include <linux/seq_file.h>
389
390 static char * const migratetype_names[MIGRATE_TYPES] = {
391         "Unmovable",
392         "Reclaimable",
393         "Movable",
394         "Reserve",
395         "Isolate",
396 };
397
398 static void *frag_start(struct seq_file *m, loff_t *pos)
399 {
400         pg_data_t *pgdat;
401         loff_t node = *pos;
402         for (pgdat = first_online_pgdat();
403              pgdat && node;
404              pgdat = next_online_pgdat(pgdat))
405                 --node;
406
407         return pgdat;
408 }
409
410 static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
411 {
412         pg_data_t *pgdat = (pg_data_t *)arg;
413
414         (*pos)++;
415         return next_online_pgdat(pgdat);
416 }
417
418 static void frag_stop(struct seq_file *m, void *arg)
419 {
420 }
421
422 /* Walk all the zones in a node and print using a callback */
423 static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat,
424                 void (*print)(struct seq_file *m, pg_data_t *, struct zone *))
425 {
426         struct zone *zone;
427         struct zone *node_zones = pgdat->node_zones;
428         unsigned long flags;
429
430         for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
431                 if (!populated_zone(zone))
432                         continue;
433
434                 spin_lock_irqsave(&zone->lock, flags);
435                 print(m, pgdat, zone);
436                 spin_unlock_irqrestore(&zone->lock, flags);
437         }
438 }
439
440 static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,
441                                                 struct zone *zone)
442 {
443         int order;
444
445         seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
446         for (order = 0; order < MAX_ORDER; ++order)
447                 seq_printf(m, "%6lu ", zone->free_area[order].nr_free);
448         seq_putc(m, '\n');
449 }
450
451 /*
452  * This walks the free areas for each zone.
453  */
454 static int frag_show(struct seq_file *m, void *arg)
455 {
456         pg_data_t *pgdat = (pg_data_t *)arg;
457         walk_zones_in_node(m, pgdat, frag_show_print);
458         return 0;
459 }
460
461 static void pagetypeinfo_showfree_print(struct seq_file *m,
462                                         pg_data_t *pgdat, struct zone *zone)
463 {
464         int order, mtype;
465
466         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++) {
467                 seq_printf(m, "Node %4d, zone %8s, type %12s ",
468                                         pgdat->node_id,
469                                         zone->name,
470                                         migratetype_names[mtype]);
471                 for (order = 0; order < MAX_ORDER; ++order) {
472                         unsigned long freecount = 0;
473                         struct free_area *area;
474                         struct list_head *curr;
475
476                         area = &(zone->free_area[order]);
477
478                         list_for_each(curr, &area->free_list[mtype])
479                                 freecount++;
480                         seq_printf(m, "%6lu ", freecount);
481                 }
482                 seq_putc(m, '\n');
483         }
484 }
485
486 /* Print out the free pages at each order for each migatetype */
487 static int pagetypeinfo_showfree(struct seq_file *m, void *arg)
488 {
489         int order;
490         pg_data_t *pgdat = (pg_data_t *)arg;
491
492         /* Print header */
493         seq_printf(m, "%-43s ", "Free pages count per migrate type at order");
494         for (order = 0; order < MAX_ORDER; ++order)
495                 seq_printf(m, "%6d ", order);
496         seq_putc(m, '\n');
497
498         walk_zones_in_node(m, pgdat, pagetypeinfo_showfree_print);
499
500         return 0;
501 }
502
503 static void pagetypeinfo_showblockcount_print(struct seq_file *m,
504                                         pg_data_t *pgdat, struct zone *zone)
505 {
506         int mtype;
507         unsigned long pfn;
508         unsigned long start_pfn = zone->zone_start_pfn;
509         unsigned long end_pfn = start_pfn + zone->spanned_pages;
510         unsigned long count[MIGRATE_TYPES] = { 0, };
511
512         for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
513                 struct page *page;
514
515                 if (!pfn_valid(pfn))
516                         continue;
517
518                 page = pfn_to_page(pfn);
519 #ifdef CONFIG_ARCH_FLATMEM_HAS_HOLES
520                 /*
521                  * Ordinarily, memory holes in flatmem still have a valid
522                  * memmap for the PFN range. However, an architecture for
523                  * embedded systems (e.g. ARM) can free up the memmap backing
524                  * holes to save memory on the assumption the memmap is
525                  * never used. The page_zone linkages are then broken even
526                  * though pfn_valid() returns true. Skip the page if the
527                  * linkages are broken. Even if this test passed, the impact
528                  * is that the counters for the movable type are off but
529                  * fragmentation monitoring is likely meaningless on small
530                  * systems.
531                  */
532                 if (page_zone(page) != zone)
533                         continue;
534 #endif
535                 mtype = get_pageblock_migratetype(page);
536
537                 if (mtype < MIGRATE_TYPES)
538                         count[mtype]++;
539         }
540
541         /* Print counts */
542         seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
543         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
544                 seq_printf(m, "%12lu ", count[mtype]);
545         seq_putc(m, '\n');
546 }
547
548 /* Print out the free pages at each order for each migratetype */
549 static int pagetypeinfo_showblockcount(struct seq_file *m, void *arg)
550 {
551         int mtype;
552         pg_data_t *pgdat = (pg_data_t *)arg;
553
554         seq_printf(m, "\n%-23s", "Number of blocks type ");
555         for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
556                 seq_printf(m, "%12s ", migratetype_names[mtype]);
557         seq_putc(m, '\n');
558         walk_zones_in_node(m, pgdat, pagetypeinfo_showblockcount_print);
559
560         return 0;
561 }
562
563 /*
564  * This prints out statistics in relation to grouping pages by mobility.
565  * It is expensive to collect so do not constantly read the file.
566  */
567 static int pagetypeinfo_show(struct seq_file *m, void *arg)
568 {
569         pg_data_t *pgdat = (pg_data_t *)arg;
570
571         /* check memoryless node */
572         if (!node_state(pgdat->node_id, N_HIGH_MEMORY))
573                 return 0;
574
575         seq_printf(m, "Page block order: %d\n", pageblock_order);
576         seq_printf(m, "Pages per block:  %lu\n", pageblock_nr_pages);
577         seq_putc(m, '\n');
578         pagetypeinfo_showfree(m, pgdat);
579         pagetypeinfo_showblockcount(m, pgdat);
580
581         return 0;
582 }
583
584 const struct seq_operations fragmentation_op = {
585         .start  = frag_start,
586         .next   = frag_next,
587         .stop   = frag_stop,
588         .show   = frag_show,
589 };
590
591 const struct seq_operations pagetypeinfo_op = {
592         .start  = frag_start,
593         .next   = frag_next,
594         .stop   = frag_stop,
595         .show   = pagetypeinfo_show,
596 };
597
598 #ifdef CONFIG_ZONE_DMA
599 #define TEXT_FOR_DMA(xx) xx "_dma",
600 #else
601 #define TEXT_FOR_DMA(xx)
602 #endif
603
604 #ifdef CONFIG_ZONE_DMA32
605 #define TEXT_FOR_DMA32(xx) xx "_dma32",
606 #else
607 #define TEXT_FOR_DMA32(xx)
608 #endif
609
610 #ifdef CONFIG_HIGHMEM
611 #define TEXT_FOR_HIGHMEM(xx) xx "_high",
612 #else
613 #define TEXT_FOR_HIGHMEM(xx)
614 #endif
615
616 #define TEXTS_FOR_ZONES(xx) TEXT_FOR_DMA(xx) TEXT_FOR_DMA32(xx) xx "_normal", \
617                                         TEXT_FOR_HIGHMEM(xx) xx "_movable",
618
619 static const char * const vmstat_text[] = {
620         /* Zoned VM counters */
621         "nr_free_pages",
622         "nr_inactive",
623         "nr_active",
624         "nr_anon_pages",
625         "nr_mapped",
626         "nr_file_pages",
627         "nr_dirty",
628         "nr_writeback",
629         "nr_slab_reclaimable",
630         "nr_slab_unreclaimable",
631         "nr_page_table_pages",
632         "nr_unstable",
633         "nr_bounce",
634         "nr_vmscan_write",
635         "nr_writeback_temp",
636
637 #ifdef CONFIG_NUMA
638         "numa_hit",
639         "numa_miss",
640         "numa_foreign",
641         "numa_interleave",
642         "numa_local",
643         "numa_other",
644 #endif
645
646 #ifdef CONFIG_VM_EVENT_COUNTERS
647         "pgpgin",
648         "pgpgout",
649         "pswpin",
650         "pswpout",
651
652         TEXTS_FOR_ZONES("pgalloc")
653
654         "pgfree",
655         "pgactivate",
656         "pgdeactivate",
657
658         "pgfault",
659         "pgmajfault",
660
661         TEXTS_FOR_ZONES("pgrefill")
662         TEXTS_FOR_ZONES("pgsteal")
663         TEXTS_FOR_ZONES("pgscan_kswapd")
664         TEXTS_FOR_ZONES("pgscan_direct")
665
666         "pginodesteal",
667         "slabs_scanned",
668         "kswapd_steal",
669         "kswapd_inodesteal",
670         "pageoutrun",
671         "allocstall",
672
673         "pgrotated",
674 #ifdef CONFIG_HUGETLB_PAGE
675         "htlb_buddy_alloc_success",
676         "htlb_buddy_alloc_fail",
677 #endif
678 #endif
679 };
680
681 static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
682                                                         struct zone *zone)
683 {
684         int i;
685         seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name);
686         seq_printf(m,
687                    "\n  pages free     %lu"
688                    "\n        min      %lu"
689                    "\n        low      %lu"
690                    "\n        high     %lu"
691                    "\n        scanned  %lu (a: %lu i: %lu)"
692                    "\n        spanned  %lu"
693                    "\n        present  %lu",
694                    zone_page_state(zone, NR_FREE_PAGES),
695                    zone->pages_min,
696                    zone->pages_low,
697                    zone->pages_high,
698                    zone->pages_scanned,
699                    zone->lru[LRU_ACTIVE].nr_scan,
700                    zone->lru[LRU_INACTIVE].nr_scan,
701                    zone->spanned_pages,
702                    zone->present_pages);
703
704         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
705                 seq_printf(m, "\n    %-12s %lu", vmstat_text[i],
706                                 zone_page_state(zone, i));
707
708         seq_printf(m,
709                    "\n        protection: (%lu",
710                    zone->lowmem_reserve[0]);
711         for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++)
712                 seq_printf(m, ", %lu", zone->lowmem_reserve[i]);
713         seq_printf(m,
714                    ")"
715                    "\n  pagesets");
716         for_each_online_cpu(i) {
717                 struct per_cpu_pageset *pageset;
718
719                 pageset = zone_pcp(zone, i);
720                 seq_printf(m,
721                            "\n    cpu: %i"
722                            "\n              count: %i"
723                            "\n              high:  %i"
724                            "\n              batch: %i",
725                            i,
726                            pageset->pcp.count,
727                            pageset->pcp.high,
728                            pageset->pcp.batch);
729 #ifdef CONFIG_SMP
730                 seq_printf(m, "\n  vm stats threshold: %d",
731                                 pageset->stat_threshold);
732 #endif
733         }
734         seq_printf(m,
735                    "\n  all_unreclaimable: %u"
736                    "\n  prev_priority:     %i"
737                    "\n  start_pfn:         %lu",
738                            zone_is_all_unreclaimable(zone),
739                    zone->prev_priority,
740                    zone->zone_start_pfn);
741         seq_putc(m, '\n');
742 }
743
744 /*
745  * Output information about zones in @pgdat.
746  */
747 static int zoneinfo_show(struct seq_file *m, void *arg)
748 {
749         pg_data_t *pgdat = (pg_data_t *)arg;
750         walk_zones_in_node(m, pgdat, zoneinfo_show_print);
751         return 0;
752 }
753
754 const struct seq_operations zoneinfo_op = {
755         .start  = frag_start, /* iterate over all zones. The same as in
756                                * fragmentation. */
757         .next   = frag_next,
758         .stop   = frag_stop,
759         .show   = zoneinfo_show,
760 };
761
762 static void *vmstat_start(struct seq_file *m, loff_t *pos)
763 {
764         unsigned long *v;
765 #ifdef CONFIG_VM_EVENT_COUNTERS
766         unsigned long *e;
767 #endif
768         int i;
769
770         if (*pos >= ARRAY_SIZE(vmstat_text))
771                 return NULL;
772
773 #ifdef CONFIG_VM_EVENT_COUNTERS
774         v = kmalloc(NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long)
775                         + sizeof(struct vm_event_state), GFP_KERNEL);
776 #else
777         v = kmalloc(NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long),
778                         GFP_KERNEL);
779 #endif
780         m->private = v;
781         if (!v)
782                 return ERR_PTR(-ENOMEM);
783         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
784                 v[i] = global_page_state(i);
785 #ifdef CONFIG_VM_EVENT_COUNTERS
786         e = v + NR_VM_ZONE_STAT_ITEMS;
787         all_vm_events(e);
788         e[PGPGIN] /= 2;         /* sectors -> kbytes */
789         e[PGPGOUT] /= 2;
790 #endif
791         return v + *pos;
792 }
793
794 static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)
795 {
796         (*pos)++;
797         if (*pos >= ARRAY_SIZE(vmstat_text))
798                 return NULL;
799         return (unsigned long *)m->private + *pos;
800 }
801
802 static int vmstat_show(struct seq_file *m, void *arg)
803 {
804         unsigned long *l = arg;
805         unsigned long off = l - (unsigned long *)m->private;
806
807         seq_printf(m, "%s %lu\n", vmstat_text[off], *l);
808         return 0;
809 }
810
811 static void vmstat_stop(struct seq_file *m, void *arg)
812 {
813         kfree(m->private);
814         m->private = NULL;
815 }
816
817 const struct seq_operations vmstat_op = {
818         .start  = vmstat_start,
819         .next   = vmstat_next,
820         .stop   = vmstat_stop,
821         .show   = vmstat_show,
822 };
823
824 #endif /* CONFIG_PROC_FS */
825
826 #ifdef CONFIG_SMP
827 static DEFINE_PER_CPU(struct delayed_work, vmstat_work);
828 int sysctl_stat_interval __read_mostly = HZ;
829
830 static void vmstat_update(struct work_struct *w)
831 {
832         refresh_cpu_vm_stats(smp_processor_id());
833         schedule_delayed_work(&__get_cpu_var(vmstat_work),
834                 sysctl_stat_interval);
835 }
836
837 static void __cpuinit start_cpu_timer(int cpu)
838 {
839         struct delayed_work *vmstat_work = &per_cpu(vmstat_work, cpu);
840
841         INIT_DELAYED_WORK_DEFERRABLE(vmstat_work, vmstat_update);
842         schedule_delayed_work_on(cpu, vmstat_work, HZ + cpu);
843 }
844
845 /*
846  * Use the cpu notifier to insure that the thresholds are recalculated
847  * when necessary.
848  */
849 static int __cpuinit vmstat_cpuup_callback(struct notifier_block *nfb,
850                 unsigned long action,
851                 void *hcpu)
852 {
853         long cpu = (long)hcpu;
854
855         switch (action) {
856         case CPU_ONLINE:
857         case CPU_ONLINE_FROZEN:
858                 start_cpu_timer(cpu);
859                 break;
860         case CPU_DOWN_PREPARE:
861         case CPU_DOWN_PREPARE_FROZEN:
862                 cancel_rearming_delayed_work(&per_cpu(vmstat_work, cpu));
863                 per_cpu(vmstat_work, cpu).work.func = NULL;
864                 break;
865         case CPU_DOWN_FAILED:
866         case CPU_DOWN_FAILED_FROZEN:
867                 start_cpu_timer(cpu);
868                 break;
869         case CPU_DEAD:
870         case CPU_DEAD_FROZEN:
871                 refresh_zone_stat_thresholds();
872                 break;
873         default:
874                 break;
875         }
876         return NOTIFY_OK;
877 }
878
879 static struct notifier_block __cpuinitdata vmstat_notifier =
880         { &vmstat_cpuup_callback, NULL, 0 };
881
882 static int __init setup_vmstat(void)
883 {
884         int cpu;
885
886         refresh_zone_stat_thresholds();
887         register_cpu_notifier(&vmstat_notifier);
888
889         for_each_online_cpu(cpu)
890                 start_cpu_timer(cpu);
891         return 0;
892 }
893 module_init(setup_vmstat)
894 #endif