ee7f896662503039339b750779c243f31a2659df
[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/config.h>
13 #include <linux/mm.h>
14 #include <linux/module.h>
15
16 /*
17  * Accumulate the page_state information across all CPUs.
18  * The result is unavoidably approximate - it can change
19  * during and after execution of this function.
20  */
21 DEFINE_PER_CPU(struct page_state, page_states) = {0};
22
23 static void __get_page_state(struct page_state *ret, int nr, cpumask_t *cpumask)
24 {
25         unsigned cpu;
26
27         memset(ret, 0, nr * sizeof(unsigned long));
28         cpus_and(*cpumask, *cpumask, cpu_online_map);
29
30         for_each_cpu_mask(cpu, *cpumask) {
31                 unsigned long *in;
32                 unsigned long *out;
33                 unsigned off;
34                 unsigned next_cpu;
35
36                 in = (unsigned long *)&per_cpu(page_states, cpu);
37
38                 next_cpu = next_cpu(cpu, *cpumask);
39                 if (likely(next_cpu < NR_CPUS))
40                         prefetch(&per_cpu(page_states, next_cpu));
41
42                 out = (unsigned long *)ret;
43                 for (off = 0; off < nr; off++)
44                         *out++ += *in++;
45         }
46 }
47
48 void get_full_page_state(struct page_state *ret)
49 {
50         cpumask_t mask = CPU_MASK_ALL;
51
52         __get_page_state(ret, sizeof(*ret) / sizeof(unsigned long), &mask);
53 }
54
55 void __mod_page_state_offset(unsigned long offset, unsigned long delta)
56 {
57         void *ptr;
58
59         ptr = &__get_cpu_var(page_states);
60         *(unsigned long *)(ptr + offset) += delta;
61 }
62 EXPORT_SYMBOL(__mod_page_state_offset);
63
64 void mod_page_state_offset(unsigned long offset, unsigned long delta)
65 {
66         unsigned long flags;
67         void *ptr;
68
69         local_irq_save(flags);
70         ptr = &__get_cpu_var(page_states);
71         *(unsigned long *)(ptr + offset) += delta;
72         local_irq_restore(flags);
73 }
74 EXPORT_SYMBOL(mod_page_state_offset);
75
76 void __get_zone_counts(unsigned long *active, unsigned long *inactive,
77                         unsigned long *free, struct pglist_data *pgdat)
78 {
79         struct zone *zones = pgdat->node_zones;
80         int i;
81
82         *active = 0;
83         *inactive = 0;
84         *free = 0;
85         for (i = 0; i < MAX_NR_ZONES; i++) {
86                 *active += zones[i].nr_active;
87                 *inactive += zones[i].nr_inactive;
88                 *free += zones[i].free_pages;
89         }
90 }
91
92 void get_zone_counts(unsigned long *active,
93                 unsigned long *inactive, unsigned long *free)
94 {
95         struct pglist_data *pgdat;
96
97         *active = 0;
98         *inactive = 0;
99         *free = 0;
100         for_each_online_pgdat(pgdat) {
101                 unsigned long l, m, n;
102                 __get_zone_counts(&l, &m, &n, pgdat);
103                 *active += l;
104                 *inactive += m;
105                 *free += n;
106         }
107 }
108
109 /*
110  * Manage combined zone based / global counters
111  *
112  * vm_stat contains the global counters
113  */
114 atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS];
115 EXPORT_SYMBOL(vm_stat);
116
117 #ifdef CONFIG_SMP
118
119 #define STAT_THRESHOLD 32
120
121 /*
122  * Determine pointer to currently valid differential byte given a zone and
123  * the item number.
124  *
125  * Preemption must be off
126  */
127 static inline s8 *diff_pointer(struct zone *zone, enum zone_stat_item item)
128 {
129         return &zone_pcp(zone, smp_processor_id())->vm_stat_diff[item];
130 }
131
132 /*
133  * For use when we know that interrupts are disabled.
134  */
135 void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
136                                 int delta)
137 {
138         s8 *p;
139         long x;
140
141         p = diff_pointer(zone, item);
142         x = delta + *p;
143
144         if (unlikely(x > STAT_THRESHOLD || x < -STAT_THRESHOLD)) {
145                 zone_page_state_add(x, zone, item);
146                 x = 0;
147         }
148
149         *p = x;
150 }
151 EXPORT_SYMBOL(__mod_zone_page_state);
152
153 /*
154  * For an unknown interrupt state
155  */
156 void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
157                                         int delta)
158 {
159         unsigned long flags;
160
161         local_irq_save(flags);
162         __mod_zone_page_state(zone, item, delta);
163         local_irq_restore(flags);
164 }
165 EXPORT_SYMBOL(mod_zone_page_state);
166
167 /*
168  * Optimized increment and decrement functions.
169  *
170  * These are only for a single page and therefore can take a struct page *
171  * argument instead of struct zone *. This allows the inclusion of the code
172  * generated for page_zone(page) into the optimized functions.
173  *
174  * No overflow check is necessary and therefore the differential can be
175  * incremented or decremented in place which may allow the compilers to
176  * generate better code.
177  *
178  * The increment or decrement is known and therefore one boundary check can
179  * be omitted.
180  *
181  * Some processors have inc/dec instructions that are atomic vs an interrupt.
182  * However, the code must first determine the differential location in a zone
183  * based on the processor number and then inc/dec the counter. There is no
184  * guarantee without disabling preemption that the processor will not change
185  * in between and therefore the atomicity vs. interrupt cannot be exploited
186  * in a useful way here.
187  */
188 static void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
189 {
190         s8 *p = diff_pointer(zone, item);
191
192         (*p)++;
193
194         if (unlikely(*p > STAT_THRESHOLD)) {
195                 zone_page_state_add(*p, zone, item);
196                 *p = 0;
197         }
198 }
199
200 void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
201 {
202         __inc_zone_state(page_zone(page), item);
203 }
204 EXPORT_SYMBOL(__inc_zone_page_state);
205
206 void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
207 {
208         struct zone *zone = page_zone(page);
209         s8 *p = diff_pointer(zone, item);
210
211         (*p)--;
212
213         if (unlikely(*p < -STAT_THRESHOLD)) {
214                 zone_page_state_add(*p, zone, item);
215                 *p = 0;
216         }
217 }
218 EXPORT_SYMBOL(__dec_zone_page_state);
219
220 void inc_zone_state(struct zone *zone, enum zone_stat_item item)
221 {
222         unsigned long flags;
223
224         local_irq_save(flags);
225         __inc_zone_state(zone, item);
226         local_irq_restore(flags);
227 }
228
229 void inc_zone_page_state(struct page *page, enum zone_stat_item item)
230 {
231         unsigned long flags;
232         struct zone *zone;
233
234         zone = page_zone(page);
235         local_irq_save(flags);
236         __inc_zone_state(zone, item);
237         local_irq_restore(flags);
238 }
239 EXPORT_SYMBOL(inc_zone_page_state);
240
241 void dec_zone_page_state(struct page *page, enum zone_stat_item item)
242 {
243         unsigned long flags;
244         struct zone *zone;
245         s8 *p;
246
247         zone = page_zone(page);
248         local_irq_save(flags);
249         p = diff_pointer(zone, item);
250
251         (*p)--;
252
253         if (unlikely(*p < -STAT_THRESHOLD)) {
254                 zone_page_state_add(*p, zone, item);
255                 *p = 0;
256         }
257         local_irq_restore(flags);
258 }
259 EXPORT_SYMBOL(dec_zone_page_state);
260
261 /*
262  * Update the zone counters for one cpu.
263  */
264 void refresh_cpu_vm_stats(int cpu)
265 {
266         struct zone *zone;
267         int i;
268         unsigned long flags;
269
270         for_each_zone(zone) {
271                 struct per_cpu_pageset *pcp;
272
273                 pcp = zone_pcp(zone, cpu);
274
275                 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
276                         if (pcp->vm_stat_diff[i]) {
277                                 local_irq_save(flags);
278                                 zone_page_state_add(pcp->vm_stat_diff[i],
279                                         zone, i);
280                                 pcp->vm_stat_diff[i] = 0;
281                                 local_irq_restore(flags);
282                         }
283         }
284 }
285
286 static void __refresh_cpu_vm_stats(void *dummy)
287 {
288         refresh_cpu_vm_stats(smp_processor_id());
289 }
290
291 /*
292  * Consolidate all counters.
293  *
294  * Note that the result is less inaccurate but still inaccurate
295  * if concurrent processes are allowed to run.
296  */
297 void refresh_vm_stats(void)
298 {
299         on_each_cpu(__refresh_cpu_vm_stats, NULL, 0, 1);
300 }
301 EXPORT_SYMBOL(refresh_vm_stats);
302
303 #endif
304
305 #ifdef CONFIG_NUMA
306 /*
307  * zonelist = the list of zones passed to the allocator
308  * z        = the zone from which the allocation occurred.
309  *
310  * Must be called with interrupts disabled.
311  */
312 void zone_statistics(struct zonelist *zonelist, struct zone *z)
313 {
314         if (z->zone_pgdat == zonelist->zones[0]->zone_pgdat) {
315                 __inc_zone_state(z, NUMA_HIT);
316         } else {
317                 __inc_zone_state(z, NUMA_MISS);
318                 __inc_zone_state(zonelist->zones[0], NUMA_FOREIGN);
319         }
320         if (z->zone_pgdat == NODE_DATA(numa_node_id()))
321                 __inc_zone_state(z, NUMA_LOCAL);
322         else
323                 __inc_zone_state(z, NUMA_OTHER);
324 }
325 #endif
326
327 #ifdef CONFIG_PROC_FS
328
329 #include <linux/seq_file.h>
330
331 static void *frag_start(struct seq_file *m, loff_t *pos)
332 {
333         pg_data_t *pgdat;
334         loff_t node = *pos;
335         for (pgdat = first_online_pgdat();
336              pgdat && node;
337              pgdat = next_online_pgdat(pgdat))
338                 --node;
339
340         return pgdat;
341 }
342
343 static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
344 {
345         pg_data_t *pgdat = (pg_data_t *)arg;
346
347         (*pos)++;
348         return next_online_pgdat(pgdat);
349 }
350
351 static void frag_stop(struct seq_file *m, void *arg)
352 {
353 }
354
355 /*
356  * This walks the free areas for each zone.
357  */
358 static int frag_show(struct seq_file *m, void *arg)
359 {
360         pg_data_t *pgdat = (pg_data_t *)arg;
361         struct zone *zone;
362         struct zone *node_zones = pgdat->node_zones;
363         unsigned long flags;
364         int order;
365
366         for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
367                 if (!populated_zone(zone))
368                         continue;
369
370                 spin_lock_irqsave(&zone->lock, flags);
371                 seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
372                 for (order = 0; order < MAX_ORDER; ++order)
373                         seq_printf(m, "%6lu ", zone->free_area[order].nr_free);
374                 spin_unlock_irqrestore(&zone->lock, flags);
375                 seq_putc(m, '\n');
376         }
377         return 0;
378 }
379
380 struct seq_operations fragmentation_op = {
381         .start  = frag_start,
382         .next   = frag_next,
383         .stop   = frag_stop,
384         .show   = frag_show,
385 };
386
387 static char *vmstat_text[] = {
388         /* Zoned VM counters */
389         "nr_anon_pages",
390         "nr_mapped",
391         "nr_file_pages",
392         "nr_slab",
393         "nr_page_table_pages",
394         "nr_dirty",
395         "nr_writeback",
396         "nr_unstable",
397         "nr_bounce",
398
399 #ifdef CONFIG_NUMA
400         "numa_hit",
401         "numa_miss",
402         "numa_foreign",
403         "numa_interleave",
404         "numa_local",
405         "numa_other",
406 #endif
407
408         /* Event counters */
409         "pgpgin",
410         "pgpgout",
411         "pswpin",
412         "pswpout",
413
414         "pgalloc_high",
415         "pgalloc_normal",
416         "pgalloc_dma32",
417         "pgalloc_dma",
418
419         "pgfree",
420         "pgactivate",
421         "pgdeactivate",
422
423         "pgfault",
424         "pgmajfault",
425
426         "pgrefill_high",
427         "pgrefill_normal",
428         "pgrefill_dma32",
429         "pgrefill_dma",
430
431         "pgsteal_high",
432         "pgsteal_normal",
433         "pgsteal_dma32",
434         "pgsteal_dma",
435
436         "pgscan_kswapd_high",
437         "pgscan_kswapd_normal",
438         "pgscan_kswapd_dma32",
439         "pgscan_kswapd_dma",
440
441         "pgscan_direct_high",
442         "pgscan_direct_normal",
443         "pgscan_direct_dma32",
444         "pgscan_direct_dma",
445
446         "pginodesteal",
447         "slabs_scanned",
448         "kswapd_steal",
449         "kswapd_inodesteal",
450         "pageoutrun",
451         "allocstall",
452
453         "pgrotated",
454 };
455
456 /*
457  * Output information about zones in @pgdat.
458  */
459 static int zoneinfo_show(struct seq_file *m, void *arg)
460 {
461         pg_data_t *pgdat = arg;
462         struct zone *zone;
463         struct zone *node_zones = pgdat->node_zones;
464         unsigned long flags;
465
466         for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; zone++) {
467                 int i;
468
469                 if (!populated_zone(zone))
470                         continue;
471
472                 spin_lock_irqsave(&zone->lock, flags);
473                 seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name);
474                 seq_printf(m,
475                            "\n  pages free     %lu"
476                            "\n        min      %lu"
477                            "\n        low      %lu"
478                            "\n        high     %lu"
479                            "\n        active   %lu"
480                            "\n        inactive %lu"
481                            "\n        scanned  %lu (a: %lu i: %lu)"
482                            "\n        spanned  %lu"
483                            "\n        present  %lu",
484                            zone->free_pages,
485                            zone->pages_min,
486                            zone->pages_low,
487                            zone->pages_high,
488                            zone->nr_active,
489                            zone->nr_inactive,
490                            zone->pages_scanned,
491                            zone->nr_scan_active, zone->nr_scan_inactive,
492                            zone->spanned_pages,
493                            zone->present_pages);
494
495                 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
496                         seq_printf(m, "\n    %-12s %lu", vmstat_text[i],
497                                         zone_page_state(zone, i));
498
499                 seq_printf(m,
500                            "\n        protection: (%lu",
501                            zone->lowmem_reserve[0]);
502                 for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++)
503                         seq_printf(m, ", %lu", zone->lowmem_reserve[i]);
504                 seq_printf(m,
505                            ")"
506                            "\n  pagesets");
507                 for_each_online_cpu(i) {
508                         struct per_cpu_pageset *pageset;
509                         int j;
510
511                         pageset = zone_pcp(zone, i);
512                         for (j = 0; j < ARRAY_SIZE(pageset->pcp); j++) {
513                                 if (pageset->pcp[j].count)
514                                         break;
515                         }
516                         if (j == ARRAY_SIZE(pageset->pcp))
517                                 continue;
518                         for (j = 0; j < ARRAY_SIZE(pageset->pcp); j++) {
519                                 seq_printf(m,
520                                            "\n    cpu: %i pcp: %i"
521                                            "\n              count: %i"
522                                            "\n              high:  %i"
523                                            "\n              batch: %i",
524                                            i, j,
525                                            pageset->pcp[j].count,
526                                            pageset->pcp[j].high,
527                                            pageset->pcp[j].batch);
528                         }
529                 }
530                 seq_printf(m,
531                            "\n  all_unreclaimable: %u"
532                            "\n  prev_priority:     %i"
533                            "\n  temp_priority:     %i"
534                            "\n  start_pfn:         %lu",
535                            zone->all_unreclaimable,
536                            zone->prev_priority,
537                            zone->temp_priority,
538                            zone->zone_start_pfn);
539                 spin_unlock_irqrestore(&zone->lock, flags);
540                 seq_putc(m, '\n');
541         }
542         return 0;
543 }
544
545 struct seq_operations zoneinfo_op = {
546         .start  = frag_start, /* iterate over all zones. The same as in
547                                * fragmentation. */
548         .next   = frag_next,
549         .stop   = frag_stop,
550         .show   = zoneinfo_show,
551 };
552
553 static void *vmstat_start(struct seq_file *m, loff_t *pos)
554 {
555         unsigned long *v;
556         struct page_state *ps;
557         int i;
558
559         if (*pos >= ARRAY_SIZE(vmstat_text))
560                 return NULL;
561
562         v = kmalloc(NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long)
563                         + sizeof(*ps), GFP_KERNEL);
564         m->private = v;
565         if (!v)
566                 return ERR_PTR(-ENOMEM);
567         for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
568                 v[i] = global_page_state(i);
569         ps = (struct page_state *)(v + NR_VM_ZONE_STAT_ITEMS);
570         get_full_page_state(ps);
571         ps->pgpgin /= 2;                /* sectors -> kbytes */
572         ps->pgpgout /= 2;
573         return v + *pos;
574 }
575
576 static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)
577 {
578         (*pos)++;
579         if (*pos >= ARRAY_SIZE(vmstat_text))
580                 return NULL;
581         return (unsigned long *)m->private + *pos;
582 }
583
584 static int vmstat_show(struct seq_file *m, void *arg)
585 {
586         unsigned long *l = arg;
587         unsigned long off = l - (unsigned long *)m->private;
588
589         seq_printf(m, "%s %lu\n", vmstat_text[off], *l);
590         return 0;
591 }
592
593 static void vmstat_stop(struct seq_file *m, void *arg)
594 {
595         kfree(m->private);
596         m->private = NULL;
597 }
598
599 struct seq_operations vmstat_op = {
600         .start  = vmstat_start,
601         .next   = vmstat_next,
602         .stop   = vmstat_stop,
603         .show   = vmstat_show,
604 };
605
606 #endif /* CONFIG_PROC_FS */
607