4 * Manages VM statistics
5 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
8 * Copyright (C) 2006 Silicon Graphics, Inc.,
9 * Christoph Lameter <christoph@lameter.com>
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>
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);
27 static void sum_vm_events(unsigned long *ret)
32 memset(ret, 0, NR_VM_EVENT_ITEMS * sizeof(unsigned long));
34 for_each_online_cpu(cpu) {
35 struct vm_event_state *this = &per_cpu(vm_event_states, cpu);
37 for (i = 0; i < NR_VM_EVENT_ITEMS; i++)
38 ret[i] += this->event[i];
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.
47 void all_vm_events(unsigned long *ret)
53 EXPORT_SYMBOL_GPL(all_vm_events);
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);
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);
86 static int calculate_threshold(struct zone *zone)
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 * ------------------------------------------------------------------
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);
134 * Refresh the thresholds for each zone.
136 static void refresh_zone_stat_thresholds(void)
142 for_each_populated_zone(zone) {
143 unsigned long max_drift, tolerate_drift;
145 threshold = calculate_threshold(zone);
147 for_each_online_cpu(cpu)
148 per_cpu_ptr(zone->pageset, cpu)->stat_threshold
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
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) +
165 * For use when we know that interrupts are disabled.
167 void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
170 struct per_cpu_pageset *pcp = this_cpu_ptr(zone->pageset);
172 s8 *p = pcp->vm_stat_diff + item;
177 if (unlikely(x > pcp->stat_threshold || x < -pcp->stat_threshold)) {
178 zone_page_state_add(x, zone, item);
183 EXPORT_SYMBOL(__mod_zone_page_state);
186 * For an unknown interrupt state
188 void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
193 local_irq_save(flags);
194 __mod_zone_page_state(zone, item, delta);
195 local_irq_restore(flags);
197 EXPORT_SYMBOL(mod_zone_page_state);
200 * Optimized increment and decrement functions.
202 * These are only for a single page and therefore can take a struct page *
203 * argument instead of struct zone *. This allows the inclusion of the code
204 * generated for page_zone(page) into the optimized functions.
206 * No overflow check is necessary and therefore the differential can be
207 * incremented or decremented in place which may allow the compilers to
208 * generate better code.
209 * The increment or decrement is known and therefore one boundary check can
212 * NOTE: These functions are very performance sensitive. Change only
215 * Some processors have inc/dec instructions that are atomic vs an interrupt.
216 * However, the code must first determine the differential location in a zone
217 * based on the processor number and then inc/dec the counter. There is no
218 * guarantee without disabling preemption that the processor will not change
219 * in between and therefore the atomicity vs. interrupt cannot be exploited
220 * in a useful way here.
222 void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
224 struct per_cpu_pageset *pcp = this_cpu_ptr(zone->pageset);
225 s8 *p = pcp->vm_stat_diff + item;
229 if (unlikely(*p > pcp->stat_threshold)) {
230 int overstep = pcp->stat_threshold / 2;
232 zone_page_state_add(*p + overstep, zone, item);
237 void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
239 __inc_zone_state(page_zone(page), item);
241 EXPORT_SYMBOL(__inc_zone_page_state);
243 void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
245 struct per_cpu_pageset *pcp = this_cpu_ptr(zone->pageset);
246 s8 *p = pcp->vm_stat_diff + item;
250 if (unlikely(*p < - pcp->stat_threshold)) {
251 int overstep = pcp->stat_threshold / 2;
253 zone_page_state_add(*p - overstep, zone, item);
258 void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
260 __dec_zone_state(page_zone(page), item);
262 EXPORT_SYMBOL(__dec_zone_page_state);
264 void inc_zone_state(struct zone *zone, enum zone_stat_item item)
268 local_irq_save(flags);
269 __inc_zone_state(zone, item);
270 local_irq_restore(flags);
273 void inc_zone_page_state(struct page *page, enum zone_stat_item item)
278 zone = page_zone(page);
279 local_irq_save(flags);
280 __inc_zone_state(zone, item);
281 local_irq_restore(flags);
283 EXPORT_SYMBOL(inc_zone_page_state);
285 void dec_zone_page_state(struct page *page, enum zone_stat_item item)
289 local_irq_save(flags);
290 __dec_zone_page_state(page, item);
291 local_irq_restore(flags);
293 EXPORT_SYMBOL(dec_zone_page_state);
296 * Update the zone counters for one cpu.
298 * The cpu specified must be either the current cpu or a processor that
299 * is not online. If it is the current cpu then the execution thread must
300 * be pinned to the current cpu.
302 * Note that refresh_cpu_vm_stats strives to only access
303 * node local memory. The per cpu pagesets on remote zones are placed
304 * in the memory local to the processor using that pageset. So the
305 * loop over all zones will access a series of cachelines local to
308 * The call to zone_page_state_add updates the cachelines with the
309 * statistics in the remote zone struct as well as the global cachelines
310 * with the global counters. These could cause remote node cache line
311 * bouncing and will have to be only done when necessary.
313 void refresh_cpu_vm_stats(int cpu)
317 int global_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
319 for_each_populated_zone(zone) {
320 struct per_cpu_pageset *p;
322 p = per_cpu_ptr(zone->pageset, cpu);
324 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
325 if (p->vm_stat_diff[i]) {
329 local_irq_save(flags);
330 v = p->vm_stat_diff[i];
331 p->vm_stat_diff[i] = 0;
332 local_irq_restore(flags);
333 atomic_long_add(v, &zone->vm_stat[i]);
336 /* 3 seconds idle till flush */
343 * Deal with draining the remote pageset of this
346 * Check if there are pages remaining in this pageset
347 * if not then there is nothing to expire.
349 if (!p->expire || !p->pcp.count)
353 * We never drain zones local to this processor.
355 if (zone_to_nid(zone) == numa_node_id()) {
365 drain_zone_pages(zone, &p->pcp);
369 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
371 atomic_long_add(global_diff[i], &vm_stat[i]);
378 * zonelist = the list of zones passed to the allocator
379 * z = the zone from which the allocation occurred.
381 * Must be called with interrupts disabled.
383 void zone_statistics(struct zone *preferred_zone, struct zone *z)
385 if (z->zone_pgdat == preferred_zone->zone_pgdat) {
386 __inc_zone_state(z, NUMA_HIT);
388 __inc_zone_state(z, NUMA_MISS);
389 __inc_zone_state(preferred_zone, NUMA_FOREIGN);
391 if (z->node == numa_node_id())
392 __inc_zone_state(z, NUMA_LOCAL);
394 __inc_zone_state(z, NUMA_OTHER);
398 #ifdef CONFIG_COMPACTION
400 struct contig_page_info {
401 unsigned long free_pages;
402 unsigned long free_blocks_total;
403 unsigned long free_blocks_suitable;
407 * Calculate the number of free pages in a zone, how many contiguous
408 * pages are free and how many are large enough to satisfy an allocation of
409 * the target size. Note that this function makes no attempt to estimate
410 * how many suitable free blocks there *might* be if MOVABLE pages were
411 * migrated. Calculating that is possible, but expensive and can be
412 * figured out from userspace
414 static void fill_contig_page_info(struct zone *zone,
415 unsigned int suitable_order,
416 struct contig_page_info *info)
420 info->free_pages = 0;
421 info->free_blocks_total = 0;
422 info->free_blocks_suitable = 0;
424 for (order = 0; order < MAX_ORDER; order++) {
425 unsigned long blocks;
427 /* Count number of free blocks */
428 blocks = zone->free_area[order].nr_free;
429 info->free_blocks_total += blocks;
431 /* Count free base pages */
432 info->free_pages += blocks << order;
434 /* Count the suitable free blocks */
435 if (order >= suitable_order)
436 info->free_blocks_suitable += blocks <<
437 (order - suitable_order);
442 * A fragmentation index only makes sense if an allocation of a requested
443 * size would fail. If that is true, the fragmentation index indicates
444 * whether external fragmentation or a lack of memory was the problem.
445 * The value can be used to determine if page reclaim or compaction
448 static int __fragmentation_index(unsigned int order, struct contig_page_info *info)
450 unsigned long requested = 1UL << order;
452 if (!info->free_blocks_total)
455 /* Fragmentation index only makes sense when a request would fail */
456 if (info->free_blocks_suitable)
460 * Index is between 0 and 1 so return within 3 decimal places
462 * 0 => allocation would fail due to lack of memory
463 * 1 => allocation would fail due to fragmentation
465 return 1000 - div_u64( (1000+(div_u64(info->free_pages * 1000ULL, requested))), info->free_blocks_total);
468 /* Same as __fragmentation index but allocs contig_page_info on stack */
469 int fragmentation_index(struct zone *zone, unsigned int order)
471 struct contig_page_info info;
473 fill_contig_page_info(zone, order, &info);
474 return __fragmentation_index(order, &info);
478 #if defined(CONFIG_PROC_FS) || defined(CONFIG_COMPACTION)
479 #include <linux/proc_fs.h>
480 #include <linux/seq_file.h>
482 static char * const migratetype_names[MIGRATE_TYPES] = {
490 static void *frag_start(struct seq_file *m, loff_t *pos)
494 for (pgdat = first_online_pgdat();
496 pgdat = next_online_pgdat(pgdat))
502 static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
504 pg_data_t *pgdat = (pg_data_t *)arg;
507 return next_online_pgdat(pgdat);
510 static void frag_stop(struct seq_file *m, void *arg)
514 /* Walk all the zones in a node and print using a callback */
515 static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat,
516 void (*print)(struct seq_file *m, pg_data_t *, struct zone *))
519 struct zone *node_zones = pgdat->node_zones;
522 for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
523 if (!populated_zone(zone))
526 spin_lock_irqsave(&zone->lock, flags);
527 print(m, pgdat, zone);
528 spin_unlock_irqrestore(&zone->lock, flags);
533 #ifdef CONFIG_PROC_FS
534 static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,
539 seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
540 for (order = 0; order < MAX_ORDER; ++order)
541 seq_printf(m, "%6lu ", zone->free_area[order].nr_free);
546 * This walks the free areas for each zone.
548 static int frag_show(struct seq_file *m, void *arg)
550 pg_data_t *pgdat = (pg_data_t *)arg;
551 walk_zones_in_node(m, pgdat, frag_show_print);
555 static void pagetypeinfo_showfree_print(struct seq_file *m,
556 pg_data_t *pgdat, struct zone *zone)
560 for (mtype = 0; mtype < MIGRATE_TYPES; mtype++) {
561 seq_printf(m, "Node %4d, zone %8s, type %12s ",
564 migratetype_names[mtype]);
565 for (order = 0; order < MAX_ORDER; ++order) {
566 unsigned long freecount = 0;
567 struct free_area *area;
568 struct list_head *curr;
570 area = &(zone->free_area[order]);
572 list_for_each(curr, &area->free_list[mtype])
574 seq_printf(m, "%6lu ", freecount);
580 /* Print out the free pages at each order for each migatetype */
581 static int pagetypeinfo_showfree(struct seq_file *m, void *arg)
584 pg_data_t *pgdat = (pg_data_t *)arg;
587 seq_printf(m, "%-43s ", "Free pages count per migrate type at order");
588 for (order = 0; order < MAX_ORDER; ++order)
589 seq_printf(m, "%6d ", order);
592 walk_zones_in_node(m, pgdat, pagetypeinfo_showfree_print);
597 static void pagetypeinfo_showblockcount_print(struct seq_file *m,
598 pg_data_t *pgdat, struct zone *zone)
602 unsigned long start_pfn = zone->zone_start_pfn;
603 unsigned long end_pfn = start_pfn + zone->spanned_pages;
604 unsigned long count[MIGRATE_TYPES] = { 0, };
606 for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
612 page = pfn_to_page(pfn);
614 /* Watch for unexpected holes punched in the memmap */
615 if (!memmap_valid_within(pfn, page, zone))
618 mtype = get_pageblock_migratetype(page);
620 if (mtype < MIGRATE_TYPES)
625 seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
626 for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
627 seq_printf(m, "%12lu ", count[mtype]);
631 /* Print out the free pages at each order for each migratetype */
632 static int pagetypeinfo_showblockcount(struct seq_file *m, void *arg)
635 pg_data_t *pgdat = (pg_data_t *)arg;
637 seq_printf(m, "\n%-23s", "Number of blocks type ");
638 for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
639 seq_printf(m, "%12s ", migratetype_names[mtype]);
641 walk_zones_in_node(m, pgdat, pagetypeinfo_showblockcount_print);
647 * This prints out statistics in relation to grouping pages by mobility.
648 * It is expensive to collect so do not constantly read the file.
650 static int pagetypeinfo_show(struct seq_file *m, void *arg)
652 pg_data_t *pgdat = (pg_data_t *)arg;
654 /* check memoryless node */
655 if (!node_state(pgdat->node_id, N_HIGH_MEMORY))
658 seq_printf(m, "Page block order: %d\n", pageblock_order);
659 seq_printf(m, "Pages per block: %lu\n", pageblock_nr_pages);
661 pagetypeinfo_showfree(m, pgdat);
662 pagetypeinfo_showblockcount(m, pgdat);
667 static const struct seq_operations fragmentation_op = {
674 static int fragmentation_open(struct inode *inode, struct file *file)
676 return seq_open(file, &fragmentation_op);
679 static const struct file_operations fragmentation_file_operations = {
680 .open = fragmentation_open,
683 .release = seq_release,
686 static const struct seq_operations pagetypeinfo_op = {
690 .show = pagetypeinfo_show,
693 static int pagetypeinfo_open(struct inode *inode, struct file *file)
695 return seq_open(file, &pagetypeinfo_op);
698 static const struct file_operations pagetypeinfo_file_ops = {
699 .open = pagetypeinfo_open,
702 .release = seq_release,
705 #ifdef CONFIG_ZONE_DMA
706 #define TEXT_FOR_DMA(xx) xx "_dma",
708 #define TEXT_FOR_DMA(xx)
711 #ifdef CONFIG_ZONE_DMA32
712 #define TEXT_FOR_DMA32(xx) xx "_dma32",
714 #define TEXT_FOR_DMA32(xx)
717 #ifdef CONFIG_HIGHMEM
718 #define TEXT_FOR_HIGHMEM(xx) xx "_high",
720 #define TEXT_FOR_HIGHMEM(xx)
723 #define TEXTS_FOR_ZONES(xx) TEXT_FOR_DMA(xx) TEXT_FOR_DMA32(xx) xx "_normal", \
724 TEXT_FOR_HIGHMEM(xx) xx "_movable",
726 static const char * const vmstat_text[] = {
727 /* Zoned VM counters */
740 "nr_slab_reclaimable",
741 "nr_slab_unreclaimable",
742 "nr_page_table_pages",
762 "nr_dirty_threshold",
763 "nr_dirty_background_threshold",
765 #ifdef CONFIG_VM_EVENT_COUNTERS
771 TEXTS_FOR_ZONES("pgalloc")
780 TEXTS_FOR_ZONES("pgrefill")
781 TEXTS_FOR_ZONES("pgsteal")
782 TEXTS_FOR_ZONES("pgscan_kswapd")
783 TEXTS_FOR_ZONES("pgscan_direct")
786 "zone_reclaim_failed",
792 "kswapd_low_wmark_hit_quickly",
793 "kswapd_high_wmark_hit_quickly",
794 "kswapd_skip_congestion_wait",
800 #ifdef CONFIG_COMPACTION
801 "compact_blocks_moved",
802 "compact_pages_moved",
803 "compact_pagemigrate_failed",
809 #ifdef CONFIG_HUGETLB_PAGE
810 "htlb_buddy_alloc_success",
811 "htlb_buddy_alloc_fail",
813 "unevictable_pgs_culled",
814 "unevictable_pgs_scanned",
815 "unevictable_pgs_rescued",
816 "unevictable_pgs_mlocked",
817 "unevictable_pgs_munlocked",
818 "unevictable_pgs_cleared",
819 "unevictable_pgs_stranded",
820 "unevictable_pgs_mlockfreed",
824 static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
828 seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name);
837 zone_nr_free_pages(zone),
838 min_wmark_pages(zone),
839 low_wmark_pages(zone),
840 high_wmark_pages(zone),
843 zone->present_pages);
845 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
846 seq_printf(m, "\n %-12s %lu", vmstat_text[i],
847 zone_page_state(zone, i));
850 "\n protection: (%lu",
851 zone->lowmem_reserve[0]);
852 for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++)
853 seq_printf(m, ", %lu", zone->lowmem_reserve[i]);
857 for_each_online_cpu(i) {
858 struct per_cpu_pageset *pageset;
860 pageset = per_cpu_ptr(zone->pageset, i);
871 seq_printf(m, "\n vm stats threshold: %d",
872 pageset->stat_threshold);
876 "\n all_unreclaimable: %u"
878 "\n inactive_ratio: %u",
879 zone->all_unreclaimable,
880 zone->zone_start_pfn,
881 zone->inactive_ratio);
886 * Output information about zones in @pgdat.
888 static int zoneinfo_show(struct seq_file *m, void *arg)
890 pg_data_t *pgdat = (pg_data_t *)arg;
891 walk_zones_in_node(m, pgdat, zoneinfo_show_print);
895 static const struct seq_operations zoneinfo_op = {
896 .start = frag_start, /* iterate over all zones. The same as in
900 .show = zoneinfo_show,
903 static int zoneinfo_open(struct inode *inode, struct file *file)
905 return seq_open(file, &zoneinfo_op);
908 static const struct file_operations proc_zoneinfo_file_operations = {
909 .open = zoneinfo_open,
912 .release = seq_release,
915 enum writeback_stat_item {
917 NR_DIRTY_BG_THRESHOLD,
918 NR_VM_WRITEBACK_STAT_ITEMS,
921 static void *vmstat_start(struct seq_file *m, loff_t *pos)
924 int i, stat_items_size;
926 if (*pos >= ARRAY_SIZE(vmstat_text))
928 stat_items_size = NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long) +
929 NR_VM_WRITEBACK_STAT_ITEMS * sizeof(unsigned long);
931 #ifdef CONFIG_VM_EVENT_COUNTERS
932 stat_items_size += sizeof(struct vm_event_state);
935 v = kmalloc(stat_items_size, GFP_KERNEL);
938 return ERR_PTR(-ENOMEM);
939 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
940 v[i] = global_page_state(i);
941 v += NR_VM_ZONE_STAT_ITEMS;
943 global_dirty_limits(v + NR_DIRTY_BG_THRESHOLD,
944 v + NR_DIRTY_THRESHOLD);
945 v += NR_VM_WRITEBACK_STAT_ITEMS;
947 #ifdef CONFIG_VM_EVENT_COUNTERS
949 v[PGPGIN] /= 2; /* sectors -> kbytes */
952 return (unsigned long *)m->private + *pos;
955 static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)
958 if (*pos >= ARRAY_SIZE(vmstat_text))
960 return (unsigned long *)m->private + *pos;
963 static int vmstat_show(struct seq_file *m, void *arg)
965 unsigned long *l = arg;
966 unsigned long off = l - (unsigned long *)m->private;
968 seq_printf(m, "%s %lu\n", vmstat_text[off], *l);
972 static void vmstat_stop(struct seq_file *m, void *arg)
978 static const struct seq_operations vmstat_op = {
979 .start = vmstat_start,
985 static int vmstat_open(struct inode *inode, struct file *file)
987 return seq_open(file, &vmstat_op);
990 static const struct file_operations proc_vmstat_file_operations = {
994 .release = seq_release,
996 #endif /* CONFIG_PROC_FS */
999 static DEFINE_PER_CPU(struct delayed_work, vmstat_work);
1000 int sysctl_stat_interval __read_mostly = HZ;
1002 static void vmstat_update(struct work_struct *w)
1004 refresh_cpu_vm_stats(smp_processor_id());
1005 schedule_delayed_work(&__get_cpu_var(vmstat_work),
1006 round_jiffies_relative(sysctl_stat_interval));
1009 static void __cpuinit start_cpu_timer(int cpu)
1011 struct delayed_work *work = &per_cpu(vmstat_work, cpu);
1013 INIT_DELAYED_WORK_DEFERRABLE(work, vmstat_update);
1014 schedule_delayed_work_on(cpu, work, __round_jiffies_relative(HZ, cpu));
1018 * Use the cpu notifier to insure that the thresholds are recalculated
1021 static int __cpuinit vmstat_cpuup_callback(struct notifier_block *nfb,
1022 unsigned long action,
1025 long cpu = (long)hcpu;
1029 case CPU_ONLINE_FROZEN:
1030 refresh_zone_stat_thresholds();
1031 start_cpu_timer(cpu);
1032 node_set_state(cpu_to_node(cpu), N_CPU);
1034 case CPU_DOWN_PREPARE:
1035 case CPU_DOWN_PREPARE_FROZEN:
1036 cancel_rearming_delayed_work(&per_cpu(vmstat_work, cpu));
1037 per_cpu(vmstat_work, cpu).work.func = NULL;
1039 case CPU_DOWN_FAILED:
1040 case CPU_DOWN_FAILED_FROZEN:
1041 start_cpu_timer(cpu);
1044 case CPU_DEAD_FROZEN:
1045 refresh_zone_stat_thresholds();
1053 static struct notifier_block __cpuinitdata vmstat_notifier =
1054 { &vmstat_cpuup_callback, NULL, 0 };
1057 static int __init setup_vmstat(void)
1062 refresh_zone_stat_thresholds();
1063 register_cpu_notifier(&vmstat_notifier);
1065 for_each_online_cpu(cpu)
1066 start_cpu_timer(cpu);
1068 #ifdef CONFIG_PROC_FS
1069 proc_create("buddyinfo", S_IRUGO, NULL, &fragmentation_file_operations);
1070 proc_create("pagetypeinfo", S_IRUGO, NULL, &pagetypeinfo_file_ops);
1071 proc_create("vmstat", S_IRUGO, NULL, &proc_vmstat_file_operations);
1072 proc_create("zoneinfo", S_IRUGO, NULL, &proc_zoneinfo_file_operations);
1076 module_init(setup_vmstat)
1078 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)
1079 #include <linux/debugfs.h>
1081 static struct dentry *extfrag_debug_root;
1084 * Return an index indicating how much of the available free memory is
1085 * unusable for an allocation of the requested size.
1087 static int unusable_free_index(unsigned int order,
1088 struct contig_page_info *info)
1090 /* No free memory is interpreted as all free memory is unusable */
1091 if (info->free_pages == 0)
1095 * Index should be a value between 0 and 1. Return a value to 3
1098 * 0 => no fragmentation
1099 * 1 => high fragmentation
1101 return div_u64((info->free_pages - (info->free_blocks_suitable << order)) * 1000ULL, info->free_pages);
1105 static void unusable_show_print(struct seq_file *m,
1106 pg_data_t *pgdat, struct zone *zone)
1110 struct contig_page_info info;
1112 seq_printf(m, "Node %d, zone %8s ",
1115 for (order = 0; order < MAX_ORDER; ++order) {
1116 fill_contig_page_info(zone, order, &info);
1117 index = unusable_free_index(order, &info);
1118 seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
1125 * Display unusable free space index
1127 * The unusable free space index measures how much of the available free
1128 * memory cannot be used to satisfy an allocation of a given size and is a
1129 * value between 0 and 1. The higher the value, the more of free memory is
1130 * unusable and by implication, the worse the external fragmentation is. This
1131 * can be expressed as a percentage by multiplying by 100.
1133 static int unusable_show(struct seq_file *m, void *arg)
1135 pg_data_t *pgdat = (pg_data_t *)arg;
1137 /* check memoryless node */
1138 if (!node_state(pgdat->node_id, N_HIGH_MEMORY))
1141 walk_zones_in_node(m, pgdat, unusable_show_print);
1146 static const struct seq_operations unusable_op = {
1147 .start = frag_start,
1150 .show = unusable_show,
1153 static int unusable_open(struct inode *inode, struct file *file)
1155 return seq_open(file, &unusable_op);
1158 static const struct file_operations unusable_file_ops = {
1159 .open = unusable_open,
1161 .llseek = seq_lseek,
1162 .release = seq_release,
1165 static void extfrag_show_print(struct seq_file *m,
1166 pg_data_t *pgdat, struct zone *zone)
1171 /* Alloc on stack as interrupts are disabled for zone walk */
1172 struct contig_page_info info;
1174 seq_printf(m, "Node %d, zone %8s ",
1177 for (order = 0; order < MAX_ORDER; ++order) {
1178 fill_contig_page_info(zone, order, &info);
1179 index = __fragmentation_index(order, &info);
1180 seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
1187 * Display fragmentation index for orders that allocations would fail for
1189 static int extfrag_show(struct seq_file *m, void *arg)
1191 pg_data_t *pgdat = (pg_data_t *)arg;
1193 walk_zones_in_node(m, pgdat, extfrag_show_print);
1198 static const struct seq_operations extfrag_op = {
1199 .start = frag_start,
1202 .show = extfrag_show,
1205 static int extfrag_open(struct inode *inode, struct file *file)
1207 return seq_open(file, &extfrag_op);
1210 static const struct file_operations extfrag_file_ops = {
1211 .open = extfrag_open,
1213 .llseek = seq_lseek,
1214 .release = seq_release,
1217 static int __init extfrag_debug_init(void)
1219 extfrag_debug_root = debugfs_create_dir("extfrag", NULL);
1220 if (!extfrag_debug_root)
1223 if (!debugfs_create_file("unusable_index", 0444,
1224 extfrag_debug_root, NULL, &unusable_file_ops))
1227 if (!debugfs_create_file("extfrag_index", 0444,
1228 extfrag_debug_root, NULL, &extfrag_file_ops))
1234 module_init(extfrag_debug_init);