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[linux/fpc-iii.git] / mm / vmstat.c
blobe8d846f57774ee631adc5836aeaa6498b39736a0
1 /*
2 * linux/mm/vmstat.c
4 * Manages VM statistics
5 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
7 * zoned VM statistics
8 * Copyright (C) 2006 Silicon Graphics, Inc.,
9 * Christoph Lameter <christoph@lameter.com>
12 #include <linux/mm.h>
13 #include <linux/err.h>
14 #include <linux/module.h>
15 #include <linux/cpu.h>
16 #include <linux/sched.h>
18 #ifdef CONFIG_VM_EVENT_COUNTERS
19 DEFINE_PER_CPU(struct vm_event_state, vm_event_states) = {{0}};
20 EXPORT_PER_CPU_SYMBOL(vm_event_states);
22 static void sum_vm_events(unsigned long *ret, cpumask_t *cpumask)
24 int cpu = 0;
25 int i;
27 memset(ret, 0, NR_VM_EVENT_ITEMS * sizeof(unsigned long));
29 cpu = first_cpu(*cpumask);
30 while (cpu < NR_CPUS) {
31 struct vm_event_state *this = &per_cpu(vm_event_states, cpu);
33 cpu = next_cpu(cpu, *cpumask);
35 if (cpu < NR_CPUS)
36 prefetch(&per_cpu(vm_event_states, cpu));
39 for (i = 0; i < NR_VM_EVENT_ITEMS; i++)
40 ret[i] += this->event[i];
45 * Accumulate the vm event counters across all CPUs.
46 * The result is unavoidably approximate - it can change
47 * during and after execution of this function.
49 void all_vm_events(unsigned long *ret)
51 sum_vm_events(ret, &cpu_online_map);
53 EXPORT_SYMBOL_GPL(all_vm_events);
55 #ifdef CONFIG_HOTPLUG
57 * Fold the foreign cpu events into our own.
59 * This is adding to the events on one processor
60 * but keeps the global counts constant.
62 void vm_events_fold_cpu(int cpu)
64 struct vm_event_state *fold_state = &per_cpu(vm_event_states, cpu);
65 int i;
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;
72 #endif /* CONFIG_HOTPLUG */
74 #endif /* CONFIG_VM_EVENT_COUNTERS */
77 * Manage combined zone based / global counters
79 * vm_stat contains the global counters
81 atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS];
82 EXPORT_SYMBOL(vm_stat);
84 #ifdef CONFIG_SMP
86 static int calculate_threshold(struct zone *zone)
88 int threshold;
89 int mem; /* memory in 128 MB units */
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.
97 * Some sample thresholds:
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
121 mem = zone->present_pages >> (27 - PAGE_SHIFT);
123 threshold = 2 * fls(num_online_cpus()) * (1 + fls(mem));
126 * Maximum threshold is 125
128 threshold = min(125, threshold);
130 return threshold;
134 * Refresh the thresholds for each zone.
136 static void refresh_zone_stat_thresholds(void)
138 struct zone *zone;
139 int cpu;
140 int threshold;
142 for_each_zone(zone) {
144 if (!zone->present_pages)
145 continue;
147 threshold = calculate_threshold(zone);
149 for_each_online_cpu(cpu)
150 zone_pcp(zone, cpu)->stat_threshold = threshold;
155 * For use when we know that interrupts are disabled.
157 void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
158 int delta)
160 struct per_cpu_pageset *pcp = zone_pcp(zone, smp_processor_id());
161 s8 *p = pcp->vm_stat_diff + item;
162 long x;
164 x = delta + *p;
166 if (unlikely(x > pcp->stat_threshold || x < -pcp->stat_threshold)) {
167 zone_page_state_add(x, zone, item);
168 x = 0;
170 *p = x;
172 EXPORT_SYMBOL(__mod_zone_page_state);
175 * For an unknown interrupt state
177 void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
178 int delta)
180 unsigned long flags;
182 local_irq_save(flags);
183 __mod_zone_page_state(zone, item, delta);
184 local_irq_restore(flags);
186 EXPORT_SYMBOL(mod_zone_page_state);
189 * Optimized increment and decrement functions.
191 * These are only for a single page and therefore can take a struct page *
192 * argument instead of struct zone *. This allows the inclusion of the code
193 * generated for page_zone(page) into the optimized functions.
195 * No overflow check is necessary and therefore the differential can be
196 * incremented or decremented in place which may allow the compilers to
197 * generate better code.
198 * The increment or decrement is known and therefore one boundary check can
199 * be omitted.
201 * NOTE: These functions are very performance sensitive. Change only
202 * with care.
204 * Some processors have inc/dec instructions that are atomic vs an interrupt.
205 * However, the code must first determine the differential location in a zone
206 * based on the processor number and then inc/dec the counter. There is no
207 * guarantee without disabling preemption that the processor will not change
208 * in between and therefore the atomicity vs. interrupt cannot be exploited
209 * in a useful way here.
211 void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
213 struct per_cpu_pageset *pcp = zone_pcp(zone, smp_processor_id());
214 s8 *p = pcp->vm_stat_diff + item;
216 (*p)++;
218 if (unlikely(*p > pcp->stat_threshold)) {
219 int overstep = pcp->stat_threshold / 2;
221 zone_page_state_add(*p + overstep, zone, item);
222 *p = -overstep;
226 void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
228 __inc_zone_state(page_zone(page), item);
230 EXPORT_SYMBOL(__inc_zone_page_state);
232 void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
234 struct per_cpu_pageset *pcp = zone_pcp(zone, smp_processor_id());
235 s8 *p = pcp->vm_stat_diff + item;
237 (*p)--;
239 if (unlikely(*p < - pcp->stat_threshold)) {
240 int overstep = pcp->stat_threshold / 2;
242 zone_page_state_add(*p - overstep, zone, item);
243 *p = overstep;
247 void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
249 __dec_zone_state(page_zone(page), item);
251 EXPORT_SYMBOL(__dec_zone_page_state);
253 void inc_zone_state(struct zone *zone, enum zone_stat_item item)
255 unsigned long flags;
257 local_irq_save(flags);
258 __inc_zone_state(zone, item);
259 local_irq_restore(flags);
262 void inc_zone_page_state(struct page *page, enum zone_stat_item item)
264 unsigned long flags;
265 struct zone *zone;
267 zone = page_zone(page);
268 local_irq_save(flags);
269 __inc_zone_state(zone, item);
270 local_irq_restore(flags);
272 EXPORT_SYMBOL(inc_zone_page_state);
274 void dec_zone_page_state(struct page *page, enum zone_stat_item item)
276 unsigned long flags;
278 local_irq_save(flags);
279 __dec_zone_page_state(page, item);
280 local_irq_restore(flags);
282 EXPORT_SYMBOL(dec_zone_page_state);
285 * Update the zone counters for one cpu.
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.
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.
298 void refresh_cpu_vm_stats(int cpu)
300 struct zone *zone;
301 int i;
302 unsigned long flags;
304 for_each_zone(zone) {
305 struct per_cpu_pageset *p;
307 if (!populated_zone(zone))
308 continue;
310 p = zone_pcp(zone, cpu);
312 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
313 if (p->vm_stat_diff[i]) {
314 local_irq_save(flags);
315 zone_page_state_add(p->vm_stat_diff[i],
316 zone, i);
317 p->vm_stat_diff[i] = 0;
318 #ifdef CONFIG_NUMA
319 /* 3 seconds idle till flush */
320 p->expire = 3;
321 #endif
322 local_irq_restore(flags);
324 #ifdef CONFIG_NUMA
326 * Deal with draining the remote pageset of this
327 * processor
329 * Check if there are pages remaining in this pageset
330 * if not then there is nothing to expire.
332 if (!p->expire || (!p->pcp[0].count && !p->pcp[1].count))
333 continue;
336 * We never drain zones local to this processor.
338 if (zone_to_nid(zone) == numa_node_id()) {
339 p->expire = 0;
340 continue;
343 p->expire--;
344 if (p->expire)
345 continue;
347 if (p->pcp[0].count)
348 drain_zone_pages(zone, p->pcp + 0);
350 if (p->pcp[1].count)
351 drain_zone_pages(zone, p->pcp + 1);
352 #endif
356 #endif
358 #ifdef CONFIG_NUMA
360 * zonelist = the list of zones passed to the allocator
361 * z = the zone from which the allocation occurred.
363 * Must be called with interrupts disabled.
365 void zone_statistics(struct zonelist *zonelist, struct zone *z)
367 if (z->zone_pgdat == zonelist->zones[0]->zone_pgdat) {
368 __inc_zone_state(z, NUMA_HIT);
369 } else {
370 __inc_zone_state(z, NUMA_MISS);
371 __inc_zone_state(zonelist->zones[0], NUMA_FOREIGN);
373 if (z->node == numa_node_id())
374 __inc_zone_state(z, NUMA_LOCAL);
375 else
376 __inc_zone_state(z, NUMA_OTHER);
378 #endif
380 #ifdef CONFIG_PROC_FS
382 #include <linux/seq_file.h>
384 static char * const migratetype_names[MIGRATE_TYPES] = {
385 "Unmovable",
386 "Reclaimable",
387 "Movable",
388 "Reserve",
391 static void *frag_start(struct seq_file *m, loff_t *pos)
393 pg_data_t *pgdat;
394 loff_t node = *pos;
395 for (pgdat = first_online_pgdat();
396 pgdat && node;
397 pgdat = next_online_pgdat(pgdat))
398 --node;
400 return pgdat;
403 static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
405 pg_data_t *pgdat = (pg_data_t *)arg;
407 (*pos)++;
408 return next_online_pgdat(pgdat);
411 static void frag_stop(struct seq_file *m, void *arg)
415 /* Walk all the zones in a node and print using a callback */
416 static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat,
417 void (*print)(struct seq_file *m, pg_data_t *, struct zone *))
419 struct zone *zone;
420 struct zone *node_zones = pgdat->node_zones;
421 unsigned long flags;
423 for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
424 if (!populated_zone(zone))
425 continue;
427 spin_lock_irqsave(&zone->lock, flags);
428 print(m, pgdat, zone);
429 spin_unlock_irqrestore(&zone->lock, flags);
433 static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,
434 struct zone *zone)
436 int order;
438 seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
439 for (order = 0; order < MAX_ORDER; ++order)
440 seq_printf(m, "%6lu ", zone->free_area[order].nr_free);
441 seq_putc(m, '\n');
445 * This walks the free areas for each zone.
447 static int frag_show(struct seq_file *m, void *arg)
449 pg_data_t *pgdat = (pg_data_t *)arg;
450 walk_zones_in_node(m, pgdat, frag_show_print);
451 return 0;
454 static void pagetypeinfo_showfree_print(struct seq_file *m,
455 pg_data_t *pgdat, struct zone *zone)
457 int order, mtype;
459 for (mtype = 0; mtype < MIGRATE_TYPES; mtype++) {
460 seq_printf(m, "Node %4d, zone %8s, type %12s ",
461 pgdat->node_id,
462 zone->name,
463 migratetype_names[mtype]);
464 for (order = 0; order < MAX_ORDER; ++order) {
465 unsigned long freecount = 0;
466 struct free_area *area;
467 struct list_head *curr;
469 area = &(zone->free_area[order]);
471 list_for_each(curr, &area->free_list[mtype])
472 freecount++;
473 seq_printf(m, "%6lu ", freecount);
475 seq_putc(m, '\n');
479 /* Print out the free pages at each order for each migatetype */
480 static int pagetypeinfo_showfree(struct seq_file *m, void *arg)
482 int order;
483 pg_data_t *pgdat = (pg_data_t *)arg;
485 /* Print header */
486 seq_printf(m, "%-43s ", "Free pages count per migrate type at order");
487 for (order = 0; order < MAX_ORDER; ++order)
488 seq_printf(m, "%6d ", order);
489 seq_putc(m, '\n');
491 walk_zones_in_node(m, pgdat, pagetypeinfo_showfree_print);
493 return 0;
496 static void pagetypeinfo_showblockcount_print(struct seq_file *m,
497 pg_data_t *pgdat, struct zone *zone)
499 int mtype;
500 unsigned long pfn;
501 unsigned long start_pfn = zone->zone_start_pfn;
502 unsigned long end_pfn = start_pfn + zone->spanned_pages;
503 unsigned long count[MIGRATE_TYPES] = { 0, };
505 for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
506 struct page *page;
508 if (!pfn_valid(pfn))
509 continue;
511 page = pfn_to_page(pfn);
512 mtype = get_pageblock_migratetype(page);
514 count[mtype]++;
517 /* Print counts */
518 seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
519 for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
520 seq_printf(m, "%12lu ", count[mtype]);
521 seq_putc(m, '\n');
524 /* Print out the free pages at each order for each migratetype */
525 static int pagetypeinfo_showblockcount(struct seq_file *m, void *arg)
527 int mtype;
528 pg_data_t *pgdat = (pg_data_t *)arg;
530 seq_printf(m, "\n%-23s", "Number of blocks type ");
531 for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
532 seq_printf(m, "%12s ", migratetype_names[mtype]);
533 seq_putc(m, '\n');
534 walk_zones_in_node(m, pgdat, pagetypeinfo_showblockcount_print);
536 return 0;
540 * This prints out statistics in relation to grouping pages by mobility.
541 * It is expensive to collect so do not constantly read the file.
543 static int pagetypeinfo_show(struct seq_file *m, void *arg)
545 pg_data_t *pgdat = (pg_data_t *)arg;
547 seq_printf(m, "Page block order: %d\n", pageblock_order);
548 seq_printf(m, "Pages per block: %lu\n", pageblock_nr_pages);
549 seq_putc(m, '\n');
550 pagetypeinfo_showfree(m, pgdat);
551 pagetypeinfo_showblockcount(m, pgdat);
553 return 0;
556 const struct seq_operations fragmentation_op = {
557 .start = frag_start,
558 .next = frag_next,
559 .stop = frag_stop,
560 .show = frag_show,
563 const struct seq_operations pagetypeinfo_op = {
564 .start = frag_start,
565 .next = frag_next,
566 .stop = frag_stop,
567 .show = pagetypeinfo_show,
570 #ifdef CONFIG_ZONE_DMA
571 #define TEXT_FOR_DMA(xx) xx "_dma",
572 #else
573 #define TEXT_FOR_DMA(xx)
574 #endif
576 #ifdef CONFIG_ZONE_DMA32
577 #define TEXT_FOR_DMA32(xx) xx "_dma32",
578 #else
579 #define TEXT_FOR_DMA32(xx)
580 #endif
582 #ifdef CONFIG_HIGHMEM
583 #define TEXT_FOR_HIGHMEM(xx) xx "_high",
584 #else
585 #define TEXT_FOR_HIGHMEM(xx)
586 #endif
588 #define TEXTS_FOR_ZONES(xx) TEXT_FOR_DMA(xx) TEXT_FOR_DMA32(xx) xx "_normal", \
589 TEXT_FOR_HIGHMEM(xx) xx "_movable",
591 static const char * const vmstat_text[] = {
592 /* Zoned VM counters */
593 "nr_free_pages",
594 "nr_inactive",
595 "nr_active",
596 "nr_anon_pages",
597 "nr_mapped",
598 "nr_file_pages",
599 "nr_dirty",
600 "nr_writeback",
601 "nr_slab_reclaimable",
602 "nr_slab_unreclaimable",
603 "nr_page_table_pages",
604 "nr_unstable",
605 "nr_bounce",
606 "nr_vmscan_write",
608 #ifdef CONFIG_NUMA
609 "numa_hit",
610 "numa_miss",
611 "numa_foreign",
612 "numa_interleave",
613 "numa_local",
614 "numa_other",
615 #endif
617 #ifdef CONFIG_VM_EVENT_COUNTERS
618 "pgpgin",
619 "pgpgout",
620 "pswpin",
621 "pswpout",
623 TEXTS_FOR_ZONES("pgalloc")
625 "pgfree",
626 "pgactivate",
627 "pgdeactivate",
629 "pgfault",
630 "pgmajfault",
632 TEXTS_FOR_ZONES("pgrefill")
633 TEXTS_FOR_ZONES("pgsteal")
634 TEXTS_FOR_ZONES("pgscan_kswapd")
635 TEXTS_FOR_ZONES("pgscan_direct")
637 "pginodesteal",
638 "slabs_scanned",
639 "kswapd_steal",
640 "kswapd_inodesteal",
641 "pageoutrun",
642 "allocstall",
644 "pgrotated",
645 #endif
648 static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
649 struct zone *zone)
651 int i;
652 seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name);
653 seq_printf(m,
654 "\n pages free %lu"
655 "\n min %lu"
656 "\n low %lu"
657 "\n high %lu"
658 "\n scanned %lu (a: %lu i: %lu)"
659 "\n spanned %lu"
660 "\n present %lu",
661 zone_page_state(zone, NR_FREE_PAGES),
662 zone->pages_min,
663 zone->pages_low,
664 zone->pages_high,
665 zone->pages_scanned,
666 zone->nr_scan_active, zone->nr_scan_inactive,
667 zone->spanned_pages,
668 zone->present_pages);
670 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
671 seq_printf(m, "\n %-12s %lu", vmstat_text[i],
672 zone_page_state(zone, i));
674 seq_printf(m,
675 "\n protection: (%lu",
676 zone->lowmem_reserve[0]);
677 for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++)
678 seq_printf(m, ", %lu", zone->lowmem_reserve[i]);
679 seq_printf(m,
681 "\n pagesets");
682 for_each_online_cpu(i) {
683 struct per_cpu_pageset *pageset;
684 int j;
686 pageset = zone_pcp(zone, i);
687 for (j = 0; j < ARRAY_SIZE(pageset->pcp); j++) {
688 seq_printf(m,
689 "\n cpu: %i pcp: %i"
690 "\n count: %i"
691 "\n high: %i"
692 "\n batch: %i",
693 i, j,
694 pageset->pcp[j].count,
695 pageset->pcp[j].high,
696 pageset->pcp[j].batch);
698 #ifdef CONFIG_SMP
699 seq_printf(m, "\n vm stats threshold: %d",
700 pageset->stat_threshold);
701 #endif
703 seq_printf(m,
704 "\n all_unreclaimable: %u"
705 "\n prev_priority: %i"
706 "\n start_pfn: %lu",
707 zone_is_all_unreclaimable(zone),
708 zone->prev_priority,
709 zone->zone_start_pfn);
710 seq_putc(m, '\n');
714 * Output information about zones in @pgdat.
716 static int zoneinfo_show(struct seq_file *m, void *arg)
718 pg_data_t *pgdat = (pg_data_t *)arg;
719 walk_zones_in_node(m, pgdat, zoneinfo_show_print);
720 return 0;
723 const struct seq_operations zoneinfo_op = {
724 .start = frag_start, /* iterate over all zones. The same as in
725 * fragmentation. */
726 .next = frag_next,
727 .stop = frag_stop,
728 .show = zoneinfo_show,
731 static void *vmstat_start(struct seq_file *m, loff_t *pos)
733 unsigned long *v;
734 #ifdef CONFIG_VM_EVENT_COUNTERS
735 unsigned long *e;
736 #endif
737 int i;
739 if (*pos >= ARRAY_SIZE(vmstat_text))
740 return NULL;
742 #ifdef CONFIG_VM_EVENT_COUNTERS
743 v = kmalloc(NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long)
744 + sizeof(struct vm_event_state), GFP_KERNEL);
745 #else
746 v = kmalloc(NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long),
747 GFP_KERNEL);
748 #endif
749 m->private = v;
750 if (!v)
751 return ERR_PTR(-ENOMEM);
752 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
753 v[i] = global_page_state(i);
754 #ifdef CONFIG_VM_EVENT_COUNTERS
755 e = v + NR_VM_ZONE_STAT_ITEMS;
756 all_vm_events(e);
757 e[PGPGIN] /= 2; /* sectors -> kbytes */
758 e[PGPGOUT] /= 2;
759 #endif
760 return v + *pos;
763 static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)
765 (*pos)++;
766 if (*pos >= ARRAY_SIZE(vmstat_text))
767 return NULL;
768 return (unsigned long *)m->private + *pos;
771 static int vmstat_show(struct seq_file *m, void *arg)
773 unsigned long *l = arg;
774 unsigned long off = l - (unsigned long *)m->private;
776 seq_printf(m, "%s %lu\n", vmstat_text[off], *l);
777 return 0;
780 static void vmstat_stop(struct seq_file *m, void *arg)
782 kfree(m->private);
783 m->private = NULL;
786 const struct seq_operations vmstat_op = {
787 .start = vmstat_start,
788 .next = vmstat_next,
789 .stop = vmstat_stop,
790 .show = vmstat_show,
793 #endif /* CONFIG_PROC_FS */
795 #ifdef CONFIG_SMP
796 static DEFINE_PER_CPU(struct delayed_work, vmstat_work);
797 int sysctl_stat_interval __read_mostly = HZ;
799 static void vmstat_update(struct work_struct *w)
801 refresh_cpu_vm_stats(smp_processor_id());
802 schedule_delayed_work(&__get_cpu_var(vmstat_work),
803 sysctl_stat_interval);
806 static void __cpuinit start_cpu_timer(int cpu)
808 struct delayed_work *vmstat_work = &per_cpu(vmstat_work, cpu);
810 INIT_DELAYED_WORK_DEFERRABLE(vmstat_work, vmstat_update);
811 schedule_delayed_work_on(cpu, vmstat_work, HZ + cpu);
815 * Use the cpu notifier to insure that the thresholds are recalculated
816 * when necessary.
818 static int __cpuinit vmstat_cpuup_callback(struct notifier_block *nfb,
819 unsigned long action,
820 void *hcpu)
822 long cpu = (long)hcpu;
824 switch (action) {
825 case CPU_ONLINE:
826 case CPU_ONLINE_FROZEN:
827 start_cpu_timer(cpu);
828 break;
829 case CPU_DOWN_PREPARE:
830 case CPU_DOWN_PREPARE_FROZEN:
831 cancel_rearming_delayed_work(&per_cpu(vmstat_work, cpu));
832 per_cpu(vmstat_work, cpu).work.func = NULL;
833 break;
834 case CPU_DOWN_FAILED:
835 case CPU_DOWN_FAILED_FROZEN:
836 start_cpu_timer(cpu);
837 break;
838 case CPU_DEAD:
839 case CPU_DEAD_FROZEN:
840 refresh_zone_stat_thresholds();
841 break;
842 default:
843 break;
845 return NOTIFY_OK;
848 static struct notifier_block __cpuinitdata vmstat_notifier =
849 { &vmstat_cpuup_callback, NULL, 0 };
851 static int __init setup_vmstat(void)
853 int cpu;
855 refresh_zone_stat_thresholds();
856 register_cpu_notifier(&vmstat_notifier);
858 for_each_online_cpu(cpu)
859 start_cpu_timer(cpu);
860 return 0;
862 module_init(setup_vmstat)
863 #endif