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>
21 #ifdef CONFIG_VM_EVENT_COUNTERS
22 DEFINE_PER_CPU(struct vm_event_state, vm_event_states) = {{0}};
23 EXPORT_PER_CPU_SYMBOL(vm_event_states);
25 static void sum_vm_events(unsigned long *ret, const struct cpumask *cpumask)
30 memset(ret, 0, NR_VM_EVENT_ITEMS * sizeof(unsigned long));
32 for_each_cpu(cpu, cpumask) {
33 struct vm_event_state *this = &per_cpu(vm_event_states, cpu);
35 for (i = 0; i < NR_VM_EVENT_ITEMS; i++)
36 ret[i] += this->event[i];
41 * Accumulate the vm event counters across all CPUs.
42 * The result is unavoidably approximate - it can change
43 * during and after execution of this function.
45 void all_vm_events(unsigned long *ret)
48 sum_vm_events(ret, cpu_online_mask);
51 EXPORT_SYMBOL_GPL(all_vm_events);
55 * Fold the foreign cpu events into our own.
57 * This is adding to the events on one processor
58 * but keeps the global counts constant.
60 void vm_events_fold_cpu(int cpu)
62 struct vm_event_state *fold_state = &per_cpu(vm_event_states, cpu);
65 for (i = 0; i < NR_VM_EVENT_ITEMS; i++) {
66 count_vm_events(i, fold_state->event[i]);
67 fold_state->event[i] = 0;
70 #endif /* CONFIG_HOTPLUG */
72 #endif /* CONFIG_VM_EVENT_COUNTERS */
75 * Manage combined zone based / global counters
77 * vm_stat contains the global counters
79 atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS];
80 EXPORT_SYMBOL(vm_stat);
84 static int calculate_threshold(struct zone *zone)
87 int mem; /* memory in 128 MB units */
90 * The threshold scales with the number of processors and the amount
91 * of memory per zone. More memory means that we can defer updates for
92 * longer, more processors could lead to more contention.
93 * fls() is used to have a cheap way of logarithmic scaling.
95 * Some sample thresholds:
97 * Threshold Processors (fls) Zonesize fls(mem+1)
98 * ------------------------------------------------------------------
115 * 125 1024 10 8-16 GB 8
116 * 125 1024 10 16-32 GB 9
119 mem = zone->present_pages >> (27 - PAGE_SHIFT);
121 threshold = 2 * fls(num_online_cpus()) * (1 + fls(mem));
124 * Maximum threshold is 125
126 threshold = min(125, threshold);
132 * Refresh the thresholds for each zone.
134 static void refresh_zone_stat_thresholds(void)
140 for_each_populated_zone(zone) {
141 threshold = calculate_threshold(zone);
143 for_each_online_cpu(cpu)
144 per_cpu_ptr(zone->pageset, cpu)->stat_threshold
150 * For use when we know that interrupts are disabled.
152 void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
155 struct per_cpu_pageset *pcp = this_cpu_ptr(zone->pageset);
157 s8 *p = pcp->vm_stat_diff + item;
162 if (unlikely(x > pcp->stat_threshold || x < -pcp->stat_threshold)) {
163 zone_page_state_add(x, zone, item);
168 EXPORT_SYMBOL(__mod_zone_page_state);
171 * For an unknown interrupt state
173 void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
178 local_irq_save(flags);
179 __mod_zone_page_state(zone, item, delta);
180 local_irq_restore(flags);
182 EXPORT_SYMBOL(mod_zone_page_state);
185 * Optimized increment and decrement functions.
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.
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
197 * NOTE: These functions are very performance sensitive. Change only
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.
207 void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
209 struct per_cpu_pageset *pcp = this_cpu_ptr(zone->pageset);
210 s8 *p = pcp->vm_stat_diff + item;
214 if (unlikely(*p > pcp->stat_threshold)) {
215 int overstep = pcp->stat_threshold / 2;
217 zone_page_state_add(*p + overstep, zone, item);
222 void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
224 __inc_zone_state(page_zone(page), item);
226 EXPORT_SYMBOL(__inc_zone_page_state);
228 void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
230 struct per_cpu_pageset *pcp = this_cpu_ptr(zone->pageset);
231 s8 *p = pcp->vm_stat_diff + item;
235 if (unlikely(*p < - pcp->stat_threshold)) {
236 int overstep = pcp->stat_threshold / 2;
238 zone_page_state_add(*p - overstep, zone, item);
243 void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
245 __dec_zone_state(page_zone(page), item);
247 EXPORT_SYMBOL(__dec_zone_page_state);
249 void inc_zone_state(struct zone *zone, enum zone_stat_item item)
253 local_irq_save(flags);
254 __inc_zone_state(zone, item);
255 local_irq_restore(flags);
258 void inc_zone_page_state(struct page *page, enum zone_stat_item item)
263 zone = page_zone(page);
264 local_irq_save(flags);
265 __inc_zone_state(zone, item);
266 local_irq_restore(flags);
268 EXPORT_SYMBOL(inc_zone_page_state);
270 void dec_zone_page_state(struct page *page, enum zone_stat_item item)
274 local_irq_save(flags);
275 __dec_zone_page_state(page, item);
276 local_irq_restore(flags);
278 EXPORT_SYMBOL(dec_zone_page_state);
281 * Update the zone counters for one cpu.
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.
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
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)
302 int global_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
304 for_each_populated_zone(zone) {
305 struct per_cpu_pageset *p;
307 p = per_cpu_ptr(zone->pageset, cpu);
309 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
310 if (p->vm_stat_diff[i]) {
314 local_irq_save(flags);
315 v = p->vm_stat_diff[i];
316 p->vm_stat_diff[i] = 0;
317 local_irq_restore(flags);
318 atomic_long_add(v, &zone->vm_stat[i]);
321 /* 3 seconds idle till flush */
328 * Deal with draining the remote pageset of this
331 * Check if there are pages remaining in this pageset
332 * if not then there is nothing to expire.
334 if (!p->expire || !p->pcp.count)
338 * We never drain zones local to this processor.
340 if (zone_to_nid(zone) == numa_node_id()) {
350 drain_zone_pages(zone, &p->pcp);
354 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
356 atomic_long_add(global_diff[i], &vm_stat[i]);
363 * zonelist = the list of zones passed to the allocator
364 * z = the zone from which the allocation occurred.
366 * Must be called with interrupts disabled.
368 void zone_statistics(struct zone *preferred_zone, struct zone *z)
370 if (z->zone_pgdat == preferred_zone->zone_pgdat) {
371 __inc_zone_state(z, NUMA_HIT);
373 __inc_zone_state(z, NUMA_MISS);
374 __inc_zone_state(preferred_zone, NUMA_FOREIGN);
376 if (z->node == numa_node_id())
377 __inc_zone_state(z, NUMA_LOCAL);
379 __inc_zone_state(z, NUMA_OTHER);
383 #ifdef CONFIG_COMPACTION
384 struct contig_page_info {
385 unsigned long free_pages;
386 unsigned long free_blocks_total;
387 unsigned long free_blocks_suitable;
391 * Calculate the number of free pages in a zone, how many contiguous
392 * pages are free and how many are large enough to satisfy an allocation of
393 * the target size. Note that this function makes no attempt to estimate
394 * how many suitable free blocks there *might* be if MOVABLE pages were
395 * migrated. Calculating that is possible, but expensive and can be
396 * figured out from userspace
398 static void fill_contig_page_info(struct zone *zone,
399 unsigned int suitable_order,
400 struct contig_page_info *info)
404 info->free_pages = 0;
405 info->free_blocks_total = 0;
406 info->free_blocks_suitable = 0;
408 for (order = 0; order < MAX_ORDER; order++) {
409 unsigned long blocks;
411 /* Count number of free blocks */
412 blocks = zone->free_area[order].nr_free;
413 info->free_blocks_total += blocks;
415 /* Count free base pages */
416 info->free_pages += blocks << order;
418 /* Count the suitable free blocks */
419 if (order >= suitable_order)
420 info->free_blocks_suitable += blocks <<
421 (order - suitable_order);
426 * A fragmentation index only makes sense if an allocation of a requested
427 * size would fail. If that is true, the fragmentation index indicates
428 * whether external fragmentation or a lack of memory was the problem.
429 * The value can be used to determine if page reclaim or compaction
432 int fragmentation_index(unsigned int order, struct contig_page_info *info)
434 unsigned long requested = 1UL << order;
436 if (!info->free_blocks_total)
439 /* Fragmentation index only makes sense when a request would fail */
440 if (info->free_blocks_suitable)
444 * Index is between 0 and 1 so return within 3 decimal places
446 * 0 => allocation would fail due to lack of memory
447 * 1 => allocation would fail due to fragmentation
449 return 1000 - div_u64( (1000+(div_u64(info->free_pages * 1000ULL, requested))), info->free_blocks_total);
453 #if defined(CONFIG_PROC_FS) || defined(CONFIG_COMPACTION)
454 #include <linux/proc_fs.h>
455 #include <linux/seq_file.h>
457 static char * const migratetype_names[MIGRATE_TYPES] = {
465 static void *frag_start(struct seq_file *m, loff_t *pos)
469 for (pgdat = first_online_pgdat();
471 pgdat = next_online_pgdat(pgdat))
477 static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
479 pg_data_t *pgdat = (pg_data_t *)arg;
482 return next_online_pgdat(pgdat);
485 static void frag_stop(struct seq_file *m, void *arg)
489 /* Walk all the zones in a node and print using a callback */
490 static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat,
491 void (*print)(struct seq_file *m, pg_data_t *, struct zone *))
494 struct zone *node_zones = pgdat->node_zones;
497 for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
498 if (!populated_zone(zone))
501 spin_lock_irqsave(&zone->lock, flags);
502 print(m, pgdat, zone);
503 spin_unlock_irqrestore(&zone->lock, flags);
508 #ifdef CONFIG_PROC_FS
509 static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,
514 seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
515 for (order = 0; order < MAX_ORDER; ++order)
516 seq_printf(m, "%6lu ", zone->free_area[order].nr_free);
521 * This walks the free areas for each zone.
523 static int frag_show(struct seq_file *m, void *arg)
525 pg_data_t *pgdat = (pg_data_t *)arg;
526 walk_zones_in_node(m, pgdat, frag_show_print);
530 static void pagetypeinfo_showfree_print(struct seq_file *m,
531 pg_data_t *pgdat, struct zone *zone)
535 for (mtype = 0; mtype < MIGRATE_TYPES; mtype++) {
536 seq_printf(m, "Node %4d, zone %8s, type %12s ",
539 migratetype_names[mtype]);
540 for (order = 0; order < MAX_ORDER; ++order) {
541 unsigned long freecount = 0;
542 struct free_area *area;
543 struct list_head *curr;
545 area = &(zone->free_area[order]);
547 list_for_each(curr, &area->free_list[mtype])
549 seq_printf(m, "%6lu ", freecount);
555 /* Print out the free pages at each order for each migatetype */
556 static int pagetypeinfo_showfree(struct seq_file *m, void *arg)
559 pg_data_t *pgdat = (pg_data_t *)arg;
562 seq_printf(m, "%-43s ", "Free pages count per migrate type at order");
563 for (order = 0; order < MAX_ORDER; ++order)
564 seq_printf(m, "%6d ", order);
567 walk_zones_in_node(m, pgdat, pagetypeinfo_showfree_print);
572 static void pagetypeinfo_showblockcount_print(struct seq_file *m,
573 pg_data_t *pgdat, struct zone *zone)
577 unsigned long start_pfn = zone->zone_start_pfn;
578 unsigned long end_pfn = start_pfn + zone->spanned_pages;
579 unsigned long count[MIGRATE_TYPES] = { 0, };
581 for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
587 page = pfn_to_page(pfn);
589 /* Watch for unexpected holes punched in the memmap */
590 if (!memmap_valid_within(pfn, page, zone))
593 mtype = get_pageblock_migratetype(page);
595 if (mtype < MIGRATE_TYPES)
600 seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
601 for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
602 seq_printf(m, "%12lu ", count[mtype]);
606 /* Print out the free pages at each order for each migratetype */
607 static int pagetypeinfo_showblockcount(struct seq_file *m, void *arg)
610 pg_data_t *pgdat = (pg_data_t *)arg;
612 seq_printf(m, "\n%-23s", "Number of blocks type ");
613 for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
614 seq_printf(m, "%12s ", migratetype_names[mtype]);
616 walk_zones_in_node(m, pgdat, pagetypeinfo_showblockcount_print);
622 * This prints out statistics in relation to grouping pages by mobility.
623 * It is expensive to collect so do not constantly read the file.
625 static int pagetypeinfo_show(struct seq_file *m, void *arg)
627 pg_data_t *pgdat = (pg_data_t *)arg;
629 /* check memoryless node */
630 if (!node_state(pgdat->node_id, N_HIGH_MEMORY))
633 seq_printf(m, "Page block order: %d\n", pageblock_order);
634 seq_printf(m, "Pages per block: %lu\n", pageblock_nr_pages);
636 pagetypeinfo_showfree(m, pgdat);
637 pagetypeinfo_showblockcount(m, pgdat);
642 static const struct seq_operations fragmentation_op = {
649 static int fragmentation_open(struct inode *inode, struct file *file)
651 return seq_open(file, &fragmentation_op);
654 static const struct file_operations fragmentation_file_operations = {
655 .open = fragmentation_open,
658 .release = seq_release,
661 static const struct seq_operations pagetypeinfo_op = {
665 .show = pagetypeinfo_show,
668 static int pagetypeinfo_open(struct inode *inode, struct file *file)
670 return seq_open(file, &pagetypeinfo_op);
673 static const struct file_operations pagetypeinfo_file_ops = {
674 .open = pagetypeinfo_open,
677 .release = seq_release,
680 #ifdef CONFIG_ZONE_DMA
681 #define TEXT_FOR_DMA(xx) xx "_dma",
683 #define TEXT_FOR_DMA(xx)
686 #ifdef CONFIG_ZONE_DMA32
687 #define TEXT_FOR_DMA32(xx) xx "_dma32",
689 #define TEXT_FOR_DMA32(xx)
692 #ifdef CONFIG_HIGHMEM
693 #define TEXT_FOR_HIGHMEM(xx) xx "_high",
695 #define TEXT_FOR_HIGHMEM(xx)
698 #define TEXTS_FOR_ZONES(xx) TEXT_FOR_DMA(xx) TEXT_FOR_DMA32(xx) xx "_normal", \
699 TEXT_FOR_HIGHMEM(xx) xx "_movable",
701 static const char * const vmstat_text[] = {
702 /* Zoned VM counters */
715 "nr_slab_reclaimable",
716 "nr_slab_unreclaimable",
717 "nr_page_table_pages",
735 #ifdef CONFIG_VM_EVENT_COUNTERS
741 TEXTS_FOR_ZONES("pgalloc")
750 TEXTS_FOR_ZONES("pgrefill")
751 TEXTS_FOR_ZONES("pgsteal")
752 TEXTS_FOR_ZONES("pgscan_kswapd")
753 TEXTS_FOR_ZONES("pgscan_direct")
756 "zone_reclaim_failed",
762 "kswapd_low_wmark_hit_quickly",
763 "kswapd_high_wmark_hit_quickly",
764 "kswapd_skip_congestion_wait",
770 #ifdef CONFIG_COMPACTION
771 "compact_blocks_moved",
772 "compact_pages_moved",
773 "compact_pagemigrate_failed",
776 #ifdef CONFIG_HUGETLB_PAGE
777 "htlb_buddy_alloc_success",
778 "htlb_buddy_alloc_fail",
780 "unevictable_pgs_culled",
781 "unevictable_pgs_scanned",
782 "unevictable_pgs_rescued",
783 "unevictable_pgs_mlocked",
784 "unevictable_pgs_munlocked",
785 "unevictable_pgs_cleared",
786 "unevictable_pgs_stranded",
787 "unevictable_pgs_mlockfreed",
791 static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
795 seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name);
804 zone_page_state(zone, NR_FREE_PAGES),
805 min_wmark_pages(zone),
806 low_wmark_pages(zone),
807 high_wmark_pages(zone),
810 zone->present_pages);
812 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
813 seq_printf(m, "\n %-12s %lu", vmstat_text[i],
814 zone_page_state(zone, i));
817 "\n protection: (%lu",
818 zone->lowmem_reserve[0]);
819 for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++)
820 seq_printf(m, ", %lu", zone->lowmem_reserve[i]);
824 for_each_online_cpu(i) {
825 struct per_cpu_pageset *pageset;
827 pageset = per_cpu_ptr(zone->pageset, i);
838 seq_printf(m, "\n vm stats threshold: %d",
839 pageset->stat_threshold);
843 "\n all_unreclaimable: %u"
844 "\n prev_priority: %i"
846 "\n inactive_ratio: %u",
847 zone->all_unreclaimable,
849 zone->zone_start_pfn,
850 zone->inactive_ratio);
855 * Output information about zones in @pgdat.
857 static int zoneinfo_show(struct seq_file *m, void *arg)
859 pg_data_t *pgdat = (pg_data_t *)arg;
860 walk_zones_in_node(m, pgdat, zoneinfo_show_print);
864 static const struct seq_operations zoneinfo_op = {
865 .start = frag_start, /* iterate over all zones. The same as in
869 .show = zoneinfo_show,
872 static int zoneinfo_open(struct inode *inode, struct file *file)
874 return seq_open(file, &zoneinfo_op);
877 static const struct file_operations proc_zoneinfo_file_operations = {
878 .open = zoneinfo_open,
881 .release = seq_release,
884 static void *vmstat_start(struct seq_file *m, loff_t *pos)
887 #ifdef CONFIG_VM_EVENT_COUNTERS
892 if (*pos >= ARRAY_SIZE(vmstat_text))
895 #ifdef CONFIG_VM_EVENT_COUNTERS
896 v = kmalloc(NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long)
897 + sizeof(struct vm_event_state), GFP_KERNEL);
899 v = kmalloc(NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long),
904 return ERR_PTR(-ENOMEM);
905 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
906 v[i] = global_page_state(i);
907 #ifdef CONFIG_VM_EVENT_COUNTERS
908 e = v + NR_VM_ZONE_STAT_ITEMS;
910 e[PGPGIN] /= 2; /* sectors -> kbytes */
916 static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)
919 if (*pos >= ARRAY_SIZE(vmstat_text))
921 return (unsigned long *)m->private + *pos;
924 static int vmstat_show(struct seq_file *m, void *arg)
926 unsigned long *l = arg;
927 unsigned long off = l - (unsigned long *)m->private;
929 seq_printf(m, "%s %lu\n", vmstat_text[off], *l);
933 static void vmstat_stop(struct seq_file *m, void *arg)
939 static const struct seq_operations vmstat_op = {
940 .start = vmstat_start,
946 static int vmstat_open(struct inode *inode, struct file *file)
948 return seq_open(file, &vmstat_op);
951 static const struct file_operations proc_vmstat_file_operations = {
955 .release = seq_release,
957 #endif /* CONFIG_PROC_FS */
960 static DEFINE_PER_CPU(struct delayed_work, vmstat_work);
961 int sysctl_stat_interval __read_mostly = HZ;
963 static void vmstat_update(struct work_struct *w)
965 refresh_cpu_vm_stats(smp_processor_id());
966 schedule_delayed_work(&__get_cpu_var(vmstat_work),
967 round_jiffies_relative(sysctl_stat_interval));
970 static void __cpuinit start_cpu_timer(int cpu)
972 struct delayed_work *work = &per_cpu(vmstat_work, cpu);
974 INIT_DELAYED_WORK_DEFERRABLE(work, vmstat_update);
975 schedule_delayed_work_on(cpu, work, __round_jiffies_relative(HZ, cpu));
979 * Use the cpu notifier to insure that the thresholds are recalculated
982 static int __cpuinit vmstat_cpuup_callback(struct notifier_block *nfb,
983 unsigned long action,
986 long cpu = (long)hcpu;
990 case CPU_ONLINE_FROZEN:
991 start_cpu_timer(cpu);
992 node_set_state(cpu_to_node(cpu), N_CPU);
994 case CPU_DOWN_PREPARE:
995 case CPU_DOWN_PREPARE_FROZEN:
996 cancel_rearming_delayed_work(&per_cpu(vmstat_work, cpu));
997 per_cpu(vmstat_work, cpu).work.func = NULL;
999 case CPU_DOWN_FAILED:
1000 case CPU_DOWN_FAILED_FROZEN:
1001 start_cpu_timer(cpu);
1004 case CPU_DEAD_FROZEN:
1005 refresh_zone_stat_thresholds();
1013 static struct notifier_block __cpuinitdata vmstat_notifier =
1014 { &vmstat_cpuup_callback, NULL, 0 };
1017 static int __init setup_vmstat(void)
1022 refresh_zone_stat_thresholds();
1023 register_cpu_notifier(&vmstat_notifier);
1025 for_each_online_cpu(cpu)
1026 start_cpu_timer(cpu);
1028 #ifdef CONFIG_PROC_FS
1029 proc_create("buddyinfo", S_IRUGO, NULL, &fragmentation_file_operations);
1030 proc_create("pagetypeinfo", S_IRUGO, NULL, &pagetypeinfo_file_ops);
1031 proc_create("vmstat", S_IRUGO, NULL, &proc_vmstat_file_operations);
1032 proc_create("zoneinfo", S_IRUGO, NULL, &proc_zoneinfo_file_operations);
1036 module_init(setup_vmstat)
1038 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)
1039 #include <linux/debugfs.h>
1041 static struct dentry *extfrag_debug_root;
1044 * Return an index indicating how much of the available free memory is
1045 * unusable for an allocation of the requested size.
1047 static int unusable_free_index(unsigned int order,
1048 struct contig_page_info *info)
1050 /* No free memory is interpreted as all free memory is unusable */
1051 if (info->free_pages == 0)
1055 * Index should be a value between 0 and 1. Return a value to 3
1058 * 0 => no fragmentation
1059 * 1 => high fragmentation
1061 return div_u64((info->free_pages - (info->free_blocks_suitable << order)) * 1000ULL, info->free_pages);
1065 static void unusable_show_print(struct seq_file *m,
1066 pg_data_t *pgdat, struct zone *zone)
1070 struct contig_page_info info;
1072 seq_printf(m, "Node %d, zone %8s ",
1075 for (order = 0; order < MAX_ORDER; ++order) {
1076 fill_contig_page_info(zone, order, &info);
1077 index = unusable_free_index(order, &info);
1078 seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
1085 * Display unusable free space index
1087 * The unusable free space index measures how much of the available free
1088 * memory cannot be used to satisfy an allocation of a given size and is a
1089 * value between 0 and 1. The higher the value, the more of free memory is
1090 * unusable and by implication, the worse the external fragmentation is. This
1091 * can be expressed as a percentage by multiplying by 100.
1093 static int unusable_show(struct seq_file *m, void *arg)
1095 pg_data_t *pgdat = (pg_data_t *)arg;
1097 /* check memoryless node */
1098 if (!node_state(pgdat->node_id, N_HIGH_MEMORY))
1101 walk_zones_in_node(m, pgdat, unusable_show_print);
1106 static const struct seq_operations unusable_op = {
1107 .start = frag_start,
1110 .show = unusable_show,
1113 static int unusable_open(struct inode *inode, struct file *file)
1115 return seq_open(file, &unusable_op);
1118 static const struct file_operations unusable_file_ops = {
1119 .open = unusable_open,
1121 .llseek = seq_lseek,
1122 .release = seq_release,
1125 static void extfrag_show_print(struct seq_file *m,
1126 pg_data_t *pgdat, struct zone *zone)
1131 /* Alloc on stack as interrupts are disabled for zone walk */
1132 struct contig_page_info info;
1134 seq_printf(m, "Node %d, zone %8s ",
1137 for (order = 0; order < MAX_ORDER; ++order) {
1138 fill_contig_page_info(zone, order, &info);
1139 index = fragmentation_index(order, &info);
1140 seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
1147 * Display fragmentation index for orders that allocations would fail for
1149 static int extfrag_show(struct seq_file *m, void *arg)
1151 pg_data_t *pgdat = (pg_data_t *)arg;
1153 walk_zones_in_node(m, pgdat, extfrag_show_print);
1158 static const struct seq_operations extfrag_op = {
1159 .start = frag_start,
1162 .show = extfrag_show,
1165 static int extfrag_open(struct inode *inode, struct file *file)
1167 return seq_open(file, &extfrag_op);
1170 static const struct file_operations extfrag_file_ops = {
1171 .open = extfrag_open,
1173 .llseek = seq_lseek,
1174 .release = seq_release,
1177 static int __init extfrag_debug_init(void)
1179 extfrag_debug_root = debugfs_create_dir("extfrag", NULL);
1180 if (!extfrag_debug_root)
1183 if (!debugfs_create_file("unusable_index", 0444,
1184 extfrag_debug_root, NULL, &unusable_file_ops))
1187 if (!debugfs_create_file("extfrag_index", 0444,
1188 extfrag_debug_root, NULL, &extfrag_file_ops))
1194 module_init(extfrag_debug_init);