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Merge master.kernel.org:/pub/scm/linux/kernel/git/mchehab/v4l-dvb
[deliverable/linux.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 #include <linux/cpu.h>
16
17 void __get_zone_counts(unsigned long *active, unsigned long *inactive,
18 unsigned long *free, struct pglist_data *pgdat)
19 {
20 struct zone *zones = pgdat->node_zones;
21 int i;
22
23 *active = 0;
24 *inactive = 0;
25 *free = 0;
26 for (i = 0; i < MAX_NR_ZONES; i++) {
27 *active += zones[i].nr_active;
28 *inactive += zones[i].nr_inactive;
29 *free += zones[i].free_pages;
30 }
31 }
32
33 void get_zone_counts(unsigned long *active,
34 unsigned long *inactive, unsigned long *free)
35 {
36 struct pglist_data *pgdat;
37
38 *active = 0;
39 *inactive = 0;
40 *free = 0;
41 for_each_online_pgdat(pgdat) {
42 unsigned long l, m, n;
43 __get_zone_counts(&l, &m, &n, pgdat);
44 *active += l;
45 *inactive += m;
46 *free += n;
47 }
48 }
49
50 #ifdef CONFIG_VM_EVENT_COUNTERS
51 DEFINE_PER_CPU(struct vm_event_state, vm_event_states) = {{0}};
52 EXPORT_PER_CPU_SYMBOL(vm_event_states);
53
54 static void sum_vm_events(unsigned long *ret, cpumask_t *cpumask)
55 {
56 int cpu = 0;
57 int i;
58
59 memset(ret, 0, NR_VM_EVENT_ITEMS * sizeof(unsigned long));
60
61 cpu = first_cpu(*cpumask);
62 while (cpu < NR_CPUS) {
63 struct vm_event_state *this = &per_cpu(vm_event_states, cpu);
64
65 cpu = next_cpu(cpu, *cpumask);
66
67 if (cpu < NR_CPUS)
68 prefetch(&per_cpu(vm_event_states, cpu));
69
70
71 for (i = 0; i < NR_VM_EVENT_ITEMS; i++)
72 ret[i] += this->event[i];
73 }
74 }
75
76 /*
77 * Accumulate the vm event counters across all CPUs.
78 * The result is unavoidably approximate - it can change
79 * during and after execution of this function.
80 */
81 void all_vm_events(unsigned long *ret)
82 {
83 sum_vm_events(ret, &cpu_online_map);
84 }
85 EXPORT_SYMBOL_GPL(all_vm_events);
86
87 #ifdef CONFIG_HOTPLUG
88 /*
89 * Fold the foreign cpu events into our own.
90 *
91 * This is adding to the events on one processor
92 * but keeps the global counts constant.
93 */
94 void vm_events_fold_cpu(int cpu)
95 {
96 struct vm_event_state *fold_state = &per_cpu(vm_event_states, cpu);
97 int i;
98
99 for (i = 0; i < NR_VM_EVENT_ITEMS; i++) {
100 count_vm_events(i, fold_state->event[i]);
101 fold_state->event[i] = 0;
102 }
103 }
104 #endif /* CONFIG_HOTPLUG */
105
106 #endif /* CONFIG_VM_EVENT_COUNTERS */
107
108 /*
109 * Manage combined zone based / global counters
110 *
111 * vm_stat contains the global counters
112 */
113 atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS];
114 EXPORT_SYMBOL(vm_stat);
115
116 #ifdef CONFIG_SMP
117
118 static int calculate_threshold(struct zone *zone)
119 {
120 int threshold;
121 int mem; /* memory in 128 MB units */
122
123 /*
124 * The threshold scales with the number of processors and the amount
125 * of memory per zone. More memory means that we can defer updates for
126 * longer, more processors could lead to more contention.
127 * fls() is used to have a cheap way of logarithmic scaling.
128 *
129 * Some sample thresholds:
130 *
131 * Threshold Processors (fls) Zonesize fls(mem+1)
132 * ------------------------------------------------------------------
133 * 8 1 1 0.9-1 GB 4
134 * 16 2 2 0.9-1 GB 4
135 * 20 2 2 1-2 GB 5
136 * 24 2 2 2-4 GB 6
137 * 28 2 2 4-8 GB 7
138 * 32 2 2 8-16 GB 8
139 * 4 2 2 <128M 1
140 * 30 4 3 2-4 GB 5
141 * 48 4 3 8-16 GB 8
142 * 32 8 4 1-2 GB 4
143 * 32 8 4 0.9-1GB 4
144 * 10 16 5 <128M 1
145 * 40 16 5 900M 4
146 * 70 64 7 2-4 GB 5
147 * 84 64 7 4-8 GB 6
148 * 108 512 9 4-8 GB 6
149 * 125 1024 10 8-16 GB 8
150 * 125 1024 10 16-32 GB 9
151 */
152
153 mem = zone->present_pages >> (27 - PAGE_SHIFT);
154
155 threshold = 2 * fls(num_online_cpus()) * (1 + fls(mem));
156
157 /*
158 * Maximum threshold is 125
159 */
160 threshold = min(125, threshold);
161
162 return threshold;
163 }
164
165 /*
166 * Refresh the thresholds for each zone.
167 */
168 static void refresh_zone_stat_thresholds(void)
169 {
170 struct zone *zone;
171 int cpu;
172 int threshold;
173
174 for_each_zone(zone) {
175
176 if (!zone->present_pages)
177 continue;
178
179 threshold = calculate_threshold(zone);
180
181 for_each_online_cpu(cpu)
182 zone_pcp(zone, cpu)->stat_threshold = threshold;
183 }
184 }
185
186 /*
187 * For use when we know that interrupts are disabled.
188 */
189 void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
190 int delta)
191 {
192 struct per_cpu_pageset *pcp = zone_pcp(zone, smp_processor_id());
193 s8 *p = pcp->vm_stat_diff + item;
194 long x;
195
196 x = delta + *p;
197
198 if (unlikely(x > pcp->stat_threshold || x < -pcp->stat_threshold)) {
199 zone_page_state_add(x, zone, item);
200 x = 0;
201 }
202 *p = x;
203 }
204 EXPORT_SYMBOL(__mod_zone_page_state);
205
206 /*
207 * For an unknown interrupt state
208 */
209 void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
210 int delta)
211 {
212 unsigned long flags;
213
214 local_irq_save(flags);
215 __mod_zone_page_state(zone, item, delta);
216 local_irq_restore(flags);
217 }
218 EXPORT_SYMBOL(mod_zone_page_state);
219
220 /*
221 * Optimized increment and decrement functions.
222 *
223 * These are only for a single page and therefore can take a struct page *
224 * argument instead of struct zone *. This allows the inclusion of the code
225 * generated for page_zone(page) into the optimized functions.
226 *
227 * No overflow check is necessary and therefore the differential can be
228 * incremented or decremented in place which may allow the compilers to
229 * generate better code.
230 * The increment or decrement is known and therefore one boundary check can
231 * be omitted.
232 *
233 * NOTE: These functions are very performance sensitive. Change only
234 * with care.
235 *
236 * Some processors have inc/dec instructions that are atomic vs an interrupt.
237 * However, the code must first determine the differential location in a zone
238 * based on the processor number and then inc/dec the counter. There is no
239 * guarantee without disabling preemption that the processor will not change
240 * in between and therefore the atomicity vs. interrupt cannot be exploited
241 * in a useful way here.
242 */
243 static void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
244 {
245 struct per_cpu_pageset *pcp = zone_pcp(zone, smp_processor_id());
246 s8 *p = pcp->vm_stat_diff + item;
247
248 (*p)++;
249
250 if (unlikely(*p > pcp->stat_threshold)) {
251 int overstep = pcp->stat_threshold / 2;
252
253 zone_page_state_add(*p + overstep, zone, item);
254 *p = -overstep;
255 }
256 }
257
258 void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
259 {
260 __inc_zone_state(page_zone(page), item);
261 }
262 EXPORT_SYMBOL(__inc_zone_page_state);
263
264 void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
265 {
266 struct zone *zone = page_zone(page);
267 struct per_cpu_pageset *pcp = zone_pcp(zone, smp_processor_id());
268 s8 *p = pcp->vm_stat_diff + item;
269
270 (*p)--;
271
272 if (unlikely(*p < - pcp->stat_threshold)) {
273 int overstep = pcp->stat_threshold / 2;
274
275 zone_page_state_add(*p - overstep, zone, item);
276 *p = overstep;
277 }
278 }
279 EXPORT_SYMBOL(__dec_zone_page_state);
280
281 void inc_zone_state(struct zone *zone, enum zone_stat_item item)
282 {
283 unsigned long flags;
284
285 local_irq_save(flags);
286 __inc_zone_state(zone, item);
287 local_irq_restore(flags);
288 }
289
290 void inc_zone_page_state(struct page *page, enum zone_stat_item item)
291 {
292 unsigned long flags;
293 struct zone *zone;
294
295 zone = page_zone(page);
296 local_irq_save(flags);
297 __inc_zone_state(zone, item);
298 local_irq_restore(flags);
299 }
300 EXPORT_SYMBOL(inc_zone_page_state);
301
302 void dec_zone_page_state(struct page *page, enum zone_stat_item item)
303 {
304 unsigned long flags;
305
306 local_irq_save(flags);
307 __dec_zone_page_state(page, item);
308 local_irq_restore(flags);
309 }
310 EXPORT_SYMBOL(dec_zone_page_state);
311
312 /*
313 * Update the zone counters for one cpu.
314 */
315 void refresh_cpu_vm_stats(int cpu)
316 {
317 struct zone *zone;
318 int i;
319 unsigned long flags;
320
321 for_each_zone(zone) {
322 struct per_cpu_pageset *pcp;
323
324 if (!populated_zone(zone))
325 continue;
326
327 pcp = zone_pcp(zone, cpu);
328
329 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
330 if (pcp->vm_stat_diff[i]) {
331 local_irq_save(flags);
332 zone_page_state_add(pcp->vm_stat_diff[i],
333 zone, i);
334 pcp->vm_stat_diff[i] = 0;
335 local_irq_restore(flags);
336 }
337 }
338 }
339
340 static void __refresh_cpu_vm_stats(void *dummy)
341 {
342 refresh_cpu_vm_stats(smp_processor_id());
343 }
344
345 /*
346 * Consolidate all counters.
347 *
348 * Note that the result is less inaccurate but still inaccurate
349 * if concurrent processes are allowed to run.
350 */
351 void refresh_vm_stats(void)
352 {
353 on_each_cpu(__refresh_cpu_vm_stats, NULL, 0, 1);
354 }
355 EXPORT_SYMBOL(refresh_vm_stats);
356
357 #endif
358
359 #ifdef CONFIG_NUMA
360 /*
361 * zonelist = the list of zones passed to the allocator
362 * z = the zone from which the allocation occurred.
363 *
364 * Must be called with interrupts disabled.
365 */
366 void zone_statistics(struct zonelist *zonelist, struct zone *z)
367 {
368 if (z->zone_pgdat == zonelist->zones[0]->zone_pgdat) {
369 __inc_zone_state(z, NUMA_HIT);
370 } else {
371 __inc_zone_state(z, NUMA_MISS);
372 __inc_zone_state(zonelist->zones[0], NUMA_FOREIGN);
373 }
374 if (z->node == numa_node_id())
375 __inc_zone_state(z, NUMA_LOCAL);
376 else
377 __inc_zone_state(z, NUMA_OTHER);
378 }
379 #endif
380
381 #ifdef CONFIG_PROC_FS
382
383 #include <linux/seq_file.h>
384
385 static void *frag_start(struct seq_file *m, loff_t *pos)
386 {
387 pg_data_t *pgdat;
388 loff_t node = *pos;
389 for (pgdat = first_online_pgdat();
390 pgdat && node;
391 pgdat = next_online_pgdat(pgdat))
392 --node;
393
394 return pgdat;
395 }
396
397 static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
398 {
399 pg_data_t *pgdat = (pg_data_t *)arg;
400
401 (*pos)++;
402 return next_online_pgdat(pgdat);
403 }
404
405 static void frag_stop(struct seq_file *m, void *arg)
406 {
407 }
408
409 /*
410 * This walks the free areas for each zone.
411 */
412 static int frag_show(struct seq_file *m, void *arg)
413 {
414 pg_data_t *pgdat = (pg_data_t *)arg;
415 struct zone *zone;
416 struct zone *node_zones = pgdat->node_zones;
417 unsigned long flags;
418 int order;
419
420 for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
421 if (!populated_zone(zone))
422 continue;
423
424 spin_lock_irqsave(&zone->lock, flags);
425 seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
426 for (order = 0; order < MAX_ORDER; ++order)
427 seq_printf(m, "%6lu ", zone->free_area[order].nr_free);
428 spin_unlock_irqrestore(&zone->lock, flags);
429 seq_putc(m, '\n');
430 }
431 return 0;
432 }
433
434 struct seq_operations fragmentation_op = {
435 .start = frag_start,
436 .next = frag_next,
437 .stop = frag_stop,
438 .show = frag_show,
439 };
440
441 #ifdef CONFIG_ZONE_DMA32
442 #define TEXT_FOR_DMA32(xx) xx "_dma32",
443 #else
444 #define TEXT_FOR_DMA32(xx)
445 #endif
446
447 #ifdef CONFIG_HIGHMEM
448 #define TEXT_FOR_HIGHMEM(xx) xx "_high",
449 #else
450 #define TEXT_FOR_HIGHMEM(xx)
451 #endif
452
453 #define TEXTS_FOR_ZONES(xx) xx "_dma", TEXT_FOR_DMA32(xx) xx "_normal", \
454 TEXT_FOR_HIGHMEM(xx)
455
456 static char *vmstat_text[] = {
457 /* Zoned VM counters */
458 "nr_anon_pages",
459 "nr_mapped",
460 "nr_file_pages",
461 "nr_slab_reclaimable",
462 "nr_slab_unreclaimable",
463 "nr_page_table_pages",
464 "nr_dirty",
465 "nr_writeback",
466 "nr_unstable",
467 "nr_bounce",
468 "nr_vmscan_write",
469
470 #ifdef CONFIG_NUMA
471 "numa_hit",
472 "numa_miss",
473 "numa_foreign",
474 "numa_interleave",
475 "numa_local",
476 "numa_other",
477 #endif
478
479 #ifdef CONFIG_VM_EVENT_COUNTERS
480 "pgpgin",
481 "pgpgout",
482 "pswpin",
483 "pswpout",
484
485 TEXTS_FOR_ZONES("pgalloc")
486
487 "pgfree",
488 "pgactivate",
489 "pgdeactivate",
490
491 "pgfault",
492 "pgmajfault",
493
494 TEXTS_FOR_ZONES("pgrefill")
495 TEXTS_FOR_ZONES("pgsteal")
496 TEXTS_FOR_ZONES("pgscan_kswapd")
497 TEXTS_FOR_ZONES("pgscan_direct")
498
499 "pginodesteal",
500 "slabs_scanned",
501 "kswapd_steal",
502 "kswapd_inodesteal",
503 "pageoutrun",
504 "allocstall",
505
506 "pgrotated",
507 #endif
508 };
509
510 /*
511 * Output information about zones in @pgdat.
512 */
513 static int zoneinfo_show(struct seq_file *m, void *arg)
514 {
515 pg_data_t *pgdat = arg;
516 struct zone *zone;
517 struct zone *node_zones = pgdat->node_zones;
518 unsigned long flags;
519
520 for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; zone++) {
521 int i;
522
523 if (!populated_zone(zone))
524 continue;
525
526 spin_lock_irqsave(&zone->lock, flags);
527 seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name);
528 seq_printf(m,
529 "\n pages free %lu"
530 "\n min %lu"
531 "\n low %lu"
532 "\n high %lu"
533 "\n active %lu"
534 "\n inactive %lu"
535 "\n scanned %lu (a: %lu i: %lu)"
536 "\n spanned %lu"
537 "\n present %lu",
538 zone->free_pages,
539 zone->pages_min,
540 zone->pages_low,
541 zone->pages_high,
542 zone->nr_active,
543 zone->nr_inactive,
544 zone->pages_scanned,
545 zone->nr_scan_active, zone->nr_scan_inactive,
546 zone->spanned_pages,
547 zone->present_pages);
548
549 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
550 seq_printf(m, "\n %-12s %lu", vmstat_text[i],
551 zone_page_state(zone, i));
552
553 seq_printf(m,
554 "\n protection: (%lu",
555 zone->lowmem_reserve[0]);
556 for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++)
557 seq_printf(m, ", %lu", zone->lowmem_reserve[i]);
558 seq_printf(m,
559 ")"
560 "\n pagesets");
561 for_each_online_cpu(i) {
562 struct per_cpu_pageset *pageset;
563 int j;
564
565 pageset = zone_pcp(zone, i);
566 for (j = 0; j < ARRAY_SIZE(pageset->pcp); j++) {
567 if (pageset->pcp[j].count)
568 break;
569 }
570 if (j == ARRAY_SIZE(pageset->pcp))
571 continue;
572 for (j = 0; j < ARRAY_SIZE(pageset->pcp); j++) {
573 seq_printf(m,
574 "\n cpu: %i pcp: %i"
575 "\n count: %i"
576 "\n high: %i"
577 "\n batch: %i",
578 i, j,
579 pageset->pcp[j].count,
580 pageset->pcp[j].high,
581 pageset->pcp[j].batch);
582 }
583 #ifdef CONFIG_SMP
584 seq_printf(m, "\n vm stats threshold: %d",
585 pageset->stat_threshold);
586 #endif
587 }
588 seq_printf(m,
589 "\n all_unreclaimable: %u"
590 "\n prev_priority: %i"
591 "\n temp_priority: %i"
592 "\n start_pfn: %lu",
593 zone->all_unreclaimable,
594 zone->prev_priority,
595 zone->temp_priority,
596 zone->zone_start_pfn);
597 spin_unlock_irqrestore(&zone->lock, flags);
598 seq_putc(m, '\n');
599 }
600 return 0;
601 }
602
603 struct seq_operations zoneinfo_op = {
604 .start = frag_start, /* iterate over all zones. The same as in
605 * fragmentation. */
606 .next = frag_next,
607 .stop = frag_stop,
608 .show = zoneinfo_show,
609 };
610
611 static void *vmstat_start(struct seq_file *m, loff_t *pos)
612 {
613 unsigned long *v;
614 #ifdef CONFIG_VM_EVENT_COUNTERS
615 unsigned long *e;
616 #endif
617 int i;
618
619 if (*pos >= ARRAY_SIZE(vmstat_text))
620 return NULL;
621
622 #ifdef CONFIG_VM_EVENT_COUNTERS
623 v = kmalloc(NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long)
624 + sizeof(struct vm_event_state), GFP_KERNEL);
625 #else
626 v = kmalloc(NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long),
627 GFP_KERNEL);
628 #endif
629 m->private = v;
630 if (!v)
631 return ERR_PTR(-ENOMEM);
632 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
633 v[i] = global_page_state(i);
634 #ifdef CONFIG_VM_EVENT_COUNTERS
635 e = v + NR_VM_ZONE_STAT_ITEMS;
636 all_vm_events(e);
637 e[PGPGIN] /= 2; /* sectors -> kbytes */
638 e[PGPGOUT] /= 2;
639 #endif
640 return v + *pos;
641 }
642
643 static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)
644 {
645 (*pos)++;
646 if (*pos >= ARRAY_SIZE(vmstat_text))
647 return NULL;
648 return (unsigned long *)m->private + *pos;
649 }
650
651 static int vmstat_show(struct seq_file *m, void *arg)
652 {
653 unsigned long *l = arg;
654 unsigned long off = l - (unsigned long *)m->private;
655
656 seq_printf(m, "%s %lu\n", vmstat_text[off], *l);
657 return 0;
658 }
659
660 static void vmstat_stop(struct seq_file *m, void *arg)
661 {
662 kfree(m->private);
663 m->private = NULL;
664 }
665
666 struct seq_operations vmstat_op = {
667 .start = vmstat_start,
668 .next = vmstat_next,
669 .stop = vmstat_stop,
670 .show = vmstat_show,
671 };
672
673 #endif /* CONFIG_PROC_FS */
674
675 #ifdef CONFIG_SMP
676 /*
677 * Use the cpu notifier to insure that the thresholds are recalculated
678 * when necessary.
679 */
680 static int __cpuinit vmstat_cpuup_callback(struct notifier_block *nfb,
681 unsigned long action,
682 void *hcpu)
683 {
684 switch (action) {
685 case CPU_UP_PREPARE:
686 case CPU_UP_CANCELED:
687 case CPU_DEAD:
688 refresh_zone_stat_thresholds();
689 break;
690 default:
691 break;
692 }
693 return NOTIFY_OK;
694 }
695
696 static struct notifier_block __cpuinitdata vmstat_notifier =
697 { &vmstat_cpuup_callback, NULL, 0 };
698
699 int __init setup_vmstat(void)
700 {
701 refresh_zone_stat_thresholds();
702 register_cpu_notifier(&vmstat_notifier);
703 return 0;
704 }
705 module_init(setup_vmstat)
706 #endif
Linux kernel - Deliverables
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