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_pressure_threshold(struct zone *zone)
89 int watermark_distance;
92 * As vmstats are not up to date, there is drift between the estimated
93 * and real values. For high thresholds and a high number of CPUs, it
94 * is possible for the min watermark to be breached while the estimated
95 * value looks fine. The pressure threshold is a reduced value such
96 * that even the maximum amount of drift will not accidentally breach
99 watermark_distance = low_wmark_pages(zone) - min_wmark_pages(zone);
100 threshold = max(1, (int)(watermark_distance / num_online_cpus()));
103 * Maximum threshold is 125
105 threshold = min(125, threshold);
110 static int calculate_threshold(struct zone *zone)
113 int mem; /* memory in 128 MB units */
116 * The threshold scales with the number of processors and the amount
117 * of memory per zone. More memory means that we can defer updates for
118 * longer, more processors could lead to more contention.
119 * fls() is used to have a cheap way of logarithmic scaling.
121 * Some sample thresholds:
123 * Threshold Processors (fls) Zonesize fls(mem+1)
124 * ------------------------------------------------------------------
141 * 125 1024 10 8-16 GB 8
142 * 125 1024 10 16-32 GB 9
145 mem = zone->present_pages >> (27 - PAGE_SHIFT);
147 threshold = 2 * fls(num_online_cpus()) * (1 + fls(mem));
150 * Maximum threshold is 125
152 threshold = min(125, threshold);
158 * Refresh the thresholds for each zone.
160 static void refresh_zone_stat_thresholds(void)
166 for_each_populated_zone(zone) {
167 unsigned long max_drift, tolerate_drift;
169 threshold = calculate_threshold(zone);
171 for_each_online_cpu(cpu)
172 per_cpu_ptr(zone->pageset, cpu)->stat_threshold
176 * Only set percpu_drift_mark if there is a danger that
177 * NR_FREE_PAGES reports the low watermark is ok when in fact
178 * the min watermark could be breached by an allocation
180 tolerate_drift = low_wmark_pages(zone) - min_wmark_pages(zone);
181 max_drift = num_online_cpus() * threshold;
182 if (max_drift > tolerate_drift)
183 zone->percpu_drift_mark = high_wmark_pages(zone) +
188 void reduce_pgdat_percpu_threshold(pg_data_t *pgdat)
196 for (i = 0; i < pgdat->nr_zones; i++) {
197 zone = &pgdat->node_zones[i];
198 if (!zone->percpu_drift_mark)
201 threshold = calculate_pressure_threshold(zone);
202 for_each_online_cpu(cpu)
203 per_cpu_ptr(zone->pageset, cpu)->stat_threshold
209 void restore_pgdat_percpu_threshold(pg_data_t *pgdat)
217 for (i = 0; i < pgdat->nr_zones; i++) {
218 zone = &pgdat->node_zones[i];
219 if (!zone->percpu_drift_mark)
222 threshold = calculate_threshold(zone);
223 for_each_online_cpu(cpu)
224 per_cpu_ptr(zone->pageset, cpu)->stat_threshold
231 * For use when we know that interrupts are disabled.
233 void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
236 struct per_cpu_pageset __percpu *pcp = zone->pageset;
237 s8 __percpu *p = pcp->vm_stat_diff + item;
241 x = delta + __this_cpu_read(*p);
243 t = __this_cpu_read(pcp->stat_threshold);
245 if (unlikely(x > t || x < -t)) {
246 zone_page_state_add(x, zone, item);
249 __this_cpu_write(*p, x);
251 EXPORT_SYMBOL(__mod_zone_page_state);
254 * Optimized increment and decrement functions.
256 * These are only for a single page and therefore can take a struct page *
257 * argument instead of struct zone *. This allows the inclusion of the code
258 * generated for page_zone(page) into the optimized functions.
260 * No overflow check is necessary and therefore the differential can be
261 * incremented or decremented in place which may allow the compilers to
262 * generate better code.
263 * The increment or decrement is known and therefore one boundary check can
266 * NOTE: These functions are very performance sensitive. Change only
269 * Some processors have inc/dec instructions that are atomic vs an interrupt.
270 * However, the code must first determine the differential location in a zone
271 * based on the processor number and then inc/dec the counter. There is no
272 * guarantee without disabling preemption that the processor will not change
273 * in between and therefore the atomicity vs. interrupt cannot be exploited
274 * in a useful way here.
276 void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
278 struct per_cpu_pageset __percpu *pcp = zone->pageset;
279 s8 __percpu *p = pcp->vm_stat_diff + item;
282 v = __this_cpu_inc_return(*p);
283 t = __this_cpu_read(pcp->stat_threshold);
284 if (unlikely(v > t)) {
285 s8 overstep = t >> 1;
287 zone_page_state_add(v + overstep, zone, item);
288 __this_cpu_write(*p, -overstep);
292 void __inc_zone_page_state(struct page *page, enum zone_stat_item item)
294 __inc_zone_state(page_zone(page), item);
296 EXPORT_SYMBOL(__inc_zone_page_state);
298 void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
300 struct per_cpu_pageset __percpu *pcp = zone->pageset;
301 s8 __percpu *p = pcp->vm_stat_diff + item;
304 v = __this_cpu_dec_return(*p);
305 t = __this_cpu_read(pcp->stat_threshold);
306 if (unlikely(v < - t)) {
307 s8 overstep = t >> 1;
309 zone_page_state_add(v - overstep, zone, item);
310 __this_cpu_write(*p, overstep);
314 void __dec_zone_page_state(struct page *page, enum zone_stat_item item)
316 __dec_zone_state(page_zone(page), item);
318 EXPORT_SYMBOL(__dec_zone_page_state);
320 #ifdef CONFIG_CMPXCHG_LOCAL
322 * If we have cmpxchg_local support then we do not need to incur the overhead
323 * that comes with local_irq_save/restore if we use this_cpu_cmpxchg.
325 * mod_state() modifies the zone counter state through atomic per cpu
328 * Overstep mode specifies how overstep should handled:
330 * 1 Overstepping half of threshold
331 * -1 Overstepping minus half of threshold
333 static inline void mod_state(struct zone *zone,
334 enum zone_stat_item item, int delta, int overstep_mode)
336 struct per_cpu_pageset __percpu *pcp = zone->pageset;
337 s8 __percpu *p = pcp->vm_stat_diff + item;
341 z = 0; /* overflow to zone counters */
344 * The fetching of the stat_threshold is racy. We may apply
345 * a counter threshold to the wrong the cpu if we get
346 * rescheduled while executing here. However, the following
347 * will apply the threshold again and therefore bring the
348 * counter under the threshold.
350 t = this_cpu_read(pcp->stat_threshold);
352 o = this_cpu_read(*p);
355 if (n > t || n < -t) {
356 int os = overstep_mode * (t >> 1) ;
358 /* Overflow must be added to zone counters */
362 } while (this_cpu_cmpxchg(*p, o, n) != o);
365 zone_page_state_add(z, zone, item);
368 void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
371 mod_state(zone, item, delta, 0);
373 EXPORT_SYMBOL(mod_zone_page_state);
375 void inc_zone_state(struct zone *zone, enum zone_stat_item item)
377 mod_state(zone, item, 1, 1);
380 void inc_zone_page_state(struct page *page, enum zone_stat_item item)
382 mod_state(page_zone(page), item, 1, 1);
384 EXPORT_SYMBOL(inc_zone_page_state);
386 void dec_zone_page_state(struct page *page, enum zone_stat_item item)
388 mod_state(page_zone(page), item, -1, -1);
390 EXPORT_SYMBOL(dec_zone_page_state);
393 * Use interrupt disable to serialize counter updates
395 void mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
400 local_irq_save(flags);
401 __mod_zone_page_state(zone, item, delta);
402 local_irq_restore(flags);
404 EXPORT_SYMBOL(mod_zone_page_state);
406 void inc_zone_state(struct zone *zone, enum zone_stat_item item)
410 local_irq_save(flags);
411 __inc_zone_state(zone, item);
412 local_irq_restore(flags);
415 void inc_zone_page_state(struct page *page, enum zone_stat_item item)
420 zone = page_zone(page);
421 local_irq_save(flags);
422 __inc_zone_state(zone, item);
423 local_irq_restore(flags);
425 EXPORT_SYMBOL(inc_zone_page_state);
427 void dec_zone_page_state(struct page *page, enum zone_stat_item item)
431 local_irq_save(flags);
432 __dec_zone_page_state(page, item);
433 local_irq_restore(flags);
435 EXPORT_SYMBOL(dec_zone_page_state);
439 * Update the zone counters for one cpu.
441 * The cpu specified must be either the current cpu or a processor that
442 * is not online. If it is the current cpu then the execution thread must
443 * be pinned to the current cpu.
445 * Note that refresh_cpu_vm_stats strives to only access
446 * node local memory. The per cpu pagesets on remote zones are placed
447 * in the memory local to the processor using that pageset. So the
448 * loop over all zones will access a series of cachelines local to
451 * The call to zone_page_state_add updates the cachelines with the
452 * statistics in the remote zone struct as well as the global cachelines
453 * with the global counters. These could cause remote node cache line
454 * bouncing and will have to be only done when necessary.
456 void refresh_cpu_vm_stats(int cpu)
460 int global_diff[NR_VM_ZONE_STAT_ITEMS] = { 0, };
462 for_each_populated_zone(zone) {
463 struct per_cpu_pageset *p;
465 p = per_cpu_ptr(zone->pageset, cpu);
467 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
468 if (p->vm_stat_diff[i]) {
472 local_irq_save(flags);
473 v = p->vm_stat_diff[i];
474 p->vm_stat_diff[i] = 0;
475 local_irq_restore(flags);
476 atomic_long_add(v, &zone->vm_stat[i]);
479 /* 3 seconds idle till flush */
486 * Deal with draining the remote pageset of this
489 * Check if there are pages remaining in this pageset
490 * if not then there is nothing to expire.
492 if (!p->expire || !p->pcp.count)
496 * We never drain zones local to this processor.
498 if (zone_to_nid(zone) == numa_node_id()) {
508 drain_zone_pages(zone, &p->pcp);
512 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
514 atomic_long_add(global_diff[i], &vm_stat[i]);
521 * zonelist = the list of zones passed to the allocator
522 * z = the zone from which the allocation occurred.
524 * Must be called with interrupts disabled.
526 void zone_statistics(struct zone *preferred_zone, struct zone *z)
528 if (z->zone_pgdat == preferred_zone->zone_pgdat) {
529 __inc_zone_state(z, NUMA_HIT);
531 __inc_zone_state(z, NUMA_MISS);
532 __inc_zone_state(preferred_zone, NUMA_FOREIGN);
534 if (z->node == numa_node_id())
535 __inc_zone_state(z, NUMA_LOCAL);
537 __inc_zone_state(z, NUMA_OTHER);
541 #ifdef CONFIG_COMPACTION
543 struct contig_page_info {
544 unsigned long free_pages;
545 unsigned long free_blocks_total;
546 unsigned long free_blocks_suitable;
550 * Calculate the number of free pages in a zone, how many contiguous
551 * pages are free and how many are large enough to satisfy an allocation of
552 * the target size. Note that this function makes no attempt to estimate
553 * how many suitable free blocks there *might* be if MOVABLE pages were
554 * migrated. Calculating that is possible, but expensive and can be
555 * figured out from userspace
557 static void fill_contig_page_info(struct zone *zone,
558 unsigned int suitable_order,
559 struct contig_page_info *info)
563 info->free_pages = 0;
564 info->free_blocks_total = 0;
565 info->free_blocks_suitable = 0;
567 for (order = 0; order < MAX_ORDER; order++) {
568 unsigned long blocks;
570 /* Count number of free blocks */
571 blocks = zone->free_area[order].nr_free;
572 info->free_blocks_total += blocks;
574 /* Count free base pages */
575 info->free_pages += blocks << order;
577 /* Count the suitable free blocks */
578 if (order >= suitable_order)
579 info->free_blocks_suitable += blocks <<
580 (order - suitable_order);
585 * A fragmentation index only makes sense if an allocation of a requested
586 * size would fail. If that is true, the fragmentation index indicates
587 * whether external fragmentation or a lack of memory was the problem.
588 * The value can be used to determine if page reclaim or compaction
591 static int __fragmentation_index(unsigned int order, struct contig_page_info *info)
593 unsigned long requested = 1UL << order;
595 if (!info->free_blocks_total)
598 /* Fragmentation index only makes sense when a request would fail */
599 if (info->free_blocks_suitable)
603 * Index is between 0 and 1 so return within 3 decimal places
605 * 0 => allocation would fail due to lack of memory
606 * 1 => allocation would fail due to fragmentation
608 return 1000 - div_u64( (1000+(div_u64(info->free_pages * 1000ULL, requested))), info->free_blocks_total);
611 /* Same as __fragmentation index but allocs contig_page_info on stack */
612 int fragmentation_index(struct zone *zone, unsigned int order)
614 struct contig_page_info info;
616 fill_contig_page_info(zone, order, &info);
617 return __fragmentation_index(order, &info);
621 #if defined(CONFIG_PROC_FS) || defined(CONFIG_COMPACTION)
622 #include <linux/proc_fs.h>
623 #include <linux/seq_file.h>
625 static char * const migratetype_names[MIGRATE_TYPES] = {
633 static void *frag_start(struct seq_file *m, loff_t *pos)
637 for (pgdat = first_online_pgdat();
639 pgdat = next_online_pgdat(pgdat))
645 static void *frag_next(struct seq_file *m, void *arg, loff_t *pos)
647 pg_data_t *pgdat = (pg_data_t *)arg;
650 return next_online_pgdat(pgdat);
653 static void frag_stop(struct seq_file *m, void *arg)
657 /* Walk all the zones in a node and print using a callback */
658 static void walk_zones_in_node(struct seq_file *m, pg_data_t *pgdat,
659 void (*print)(struct seq_file *m, pg_data_t *, struct zone *))
662 struct zone *node_zones = pgdat->node_zones;
665 for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
666 if (!populated_zone(zone))
669 spin_lock_irqsave(&zone->lock, flags);
670 print(m, pgdat, zone);
671 spin_unlock_irqrestore(&zone->lock, flags);
676 #ifdef CONFIG_PROC_FS
677 static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,
682 seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
683 for (order = 0; order < MAX_ORDER; ++order)
684 seq_printf(m, "%6lu ", zone->free_area[order].nr_free);
689 * This walks the free areas for each zone.
691 static int frag_show(struct seq_file *m, void *arg)
693 pg_data_t *pgdat = (pg_data_t *)arg;
694 walk_zones_in_node(m, pgdat, frag_show_print);
698 static void pagetypeinfo_showfree_print(struct seq_file *m,
699 pg_data_t *pgdat, struct zone *zone)
703 for (mtype = 0; mtype < MIGRATE_TYPES; mtype++) {
704 seq_printf(m, "Node %4d, zone %8s, type %12s ",
707 migratetype_names[mtype]);
708 for (order = 0; order < MAX_ORDER; ++order) {
709 unsigned long freecount = 0;
710 struct free_area *area;
711 struct list_head *curr;
713 area = &(zone->free_area[order]);
715 list_for_each(curr, &area->free_list[mtype])
717 seq_printf(m, "%6lu ", freecount);
723 /* Print out the free pages at each order for each migatetype */
724 static int pagetypeinfo_showfree(struct seq_file *m, void *arg)
727 pg_data_t *pgdat = (pg_data_t *)arg;
730 seq_printf(m, "%-43s ", "Free pages count per migrate type at order");
731 for (order = 0; order < MAX_ORDER; ++order)
732 seq_printf(m, "%6d ", order);
735 walk_zones_in_node(m, pgdat, pagetypeinfo_showfree_print);
740 static void pagetypeinfo_showblockcount_print(struct seq_file *m,
741 pg_data_t *pgdat, struct zone *zone)
745 unsigned long start_pfn = zone->zone_start_pfn;
746 unsigned long end_pfn = start_pfn + zone->spanned_pages;
747 unsigned long count[MIGRATE_TYPES] = { 0, };
749 for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
755 page = pfn_to_page(pfn);
757 /* Watch for unexpected holes punched in the memmap */
758 if (!memmap_valid_within(pfn, page, zone))
761 mtype = get_pageblock_migratetype(page);
763 if (mtype < MIGRATE_TYPES)
768 seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
769 for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
770 seq_printf(m, "%12lu ", count[mtype]);
774 /* Print out the free pages at each order for each migratetype */
775 static int pagetypeinfo_showblockcount(struct seq_file *m, void *arg)
778 pg_data_t *pgdat = (pg_data_t *)arg;
780 seq_printf(m, "\n%-23s", "Number of blocks type ");
781 for (mtype = 0; mtype < MIGRATE_TYPES; mtype++)
782 seq_printf(m, "%12s ", migratetype_names[mtype]);
784 walk_zones_in_node(m, pgdat, pagetypeinfo_showblockcount_print);
790 * This prints out statistics in relation to grouping pages by mobility.
791 * It is expensive to collect so do not constantly read the file.
793 static int pagetypeinfo_show(struct seq_file *m, void *arg)
795 pg_data_t *pgdat = (pg_data_t *)arg;
797 /* check memoryless node */
798 if (!node_state(pgdat->node_id, N_HIGH_MEMORY))
801 seq_printf(m, "Page block order: %d\n", pageblock_order);
802 seq_printf(m, "Pages per block: %lu\n", pageblock_nr_pages);
804 pagetypeinfo_showfree(m, pgdat);
805 pagetypeinfo_showblockcount(m, pgdat);
810 static const struct seq_operations fragmentation_op = {
817 static int fragmentation_open(struct inode *inode, struct file *file)
819 return seq_open(file, &fragmentation_op);
822 static const struct file_operations fragmentation_file_operations = {
823 .open = fragmentation_open,
826 .release = seq_release,
829 static const struct seq_operations pagetypeinfo_op = {
833 .show = pagetypeinfo_show,
836 static int pagetypeinfo_open(struct inode *inode, struct file *file)
838 return seq_open(file, &pagetypeinfo_op);
841 static const struct file_operations pagetypeinfo_file_ops = {
842 .open = pagetypeinfo_open,
845 .release = seq_release,
848 #ifdef CONFIG_ZONE_DMA
849 #define TEXT_FOR_DMA(xx) xx "_dma",
851 #define TEXT_FOR_DMA(xx)
854 #ifdef CONFIG_ZONE_DMA32
855 #define TEXT_FOR_DMA32(xx) xx "_dma32",
857 #define TEXT_FOR_DMA32(xx)
860 #ifdef CONFIG_HIGHMEM
861 #define TEXT_FOR_HIGHMEM(xx) xx "_high",
863 #define TEXT_FOR_HIGHMEM(xx)
866 #define TEXTS_FOR_ZONES(xx) TEXT_FOR_DMA(xx) TEXT_FOR_DMA32(xx) xx "_normal", \
867 TEXT_FOR_HIGHMEM(xx) xx "_movable",
869 static const char * const vmstat_text[] = {
870 /* Zoned VM counters */
883 "nr_slab_reclaimable",
884 "nr_slab_unreclaimable",
885 "nr_page_table_pages",
905 "nr_dirty_threshold",
906 "nr_dirty_background_threshold",
908 #ifdef CONFIG_VM_EVENT_COUNTERS
914 TEXTS_FOR_ZONES("pgalloc")
923 TEXTS_FOR_ZONES("pgrefill")
924 TEXTS_FOR_ZONES("pgsteal")
925 TEXTS_FOR_ZONES("pgscan_kswapd")
926 TEXTS_FOR_ZONES("pgscan_direct")
929 "zone_reclaim_failed",
935 "kswapd_low_wmark_hit_quickly",
936 "kswapd_high_wmark_hit_quickly",
937 "kswapd_skip_congestion_wait",
943 #ifdef CONFIG_COMPACTION
944 "compact_blocks_moved",
945 "compact_pages_moved",
946 "compact_pagemigrate_failed",
952 #ifdef CONFIG_HUGETLB_PAGE
953 "htlb_buddy_alloc_success",
954 "htlb_buddy_alloc_fail",
956 "unevictable_pgs_culled",
957 "unevictable_pgs_scanned",
958 "unevictable_pgs_rescued",
959 "unevictable_pgs_mlocked",
960 "unevictable_pgs_munlocked",
961 "unevictable_pgs_cleared",
962 "unevictable_pgs_stranded",
963 "unevictable_pgs_mlockfreed",
967 static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
971 seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name);
980 zone_page_state(zone, NR_FREE_PAGES),
981 min_wmark_pages(zone),
982 low_wmark_pages(zone),
983 high_wmark_pages(zone),
986 zone->present_pages);
988 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
989 seq_printf(m, "\n %-12s %lu", vmstat_text[i],
990 zone_page_state(zone, i));
993 "\n protection: (%lu",
994 zone->lowmem_reserve[0]);
995 for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++)
996 seq_printf(m, ", %lu", zone->lowmem_reserve[i]);
1000 for_each_online_cpu(i) {
1001 struct per_cpu_pageset *pageset;
1003 pageset = per_cpu_ptr(zone->pageset, i);
1012 pageset->pcp.batch);
1014 seq_printf(m, "\n vm stats threshold: %d",
1015 pageset->stat_threshold);
1019 "\n all_unreclaimable: %u"
1021 "\n inactive_ratio: %u",
1022 zone->all_unreclaimable,
1023 zone->zone_start_pfn,
1024 zone->inactive_ratio);
1029 * Output information about zones in @pgdat.
1031 static int zoneinfo_show(struct seq_file *m, void *arg)
1033 pg_data_t *pgdat = (pg_data_t *)arg;
1034 walk_zones_in_node(m, pgdat, zoneinfo_show_print);
1038 static const struct seq_operations zoneinfo_op = {
1039 .start = frag_start, /* iterate over all zones. The same as in
1043 .show = zoneinfo_show,
1046 static int zoneinfo_open(struct inode *inode, struct file *file)
1048 return seq_open(file, &zoneinfo_op);
1051 static const struct file_operations proc_zoneinfo_file_operations = {
1052 .open = zoneinfo_open,
1054 .llseek = seq_lseek,
1055 .release = seq_release,
1058 enum writeback_stat_item {
1060 NR_DIRTY_BG_THRESHOLD,
1061 NR_VM_WRITEBACK_STAT_ITEMS,
1064 static void *vmstat_start(struct seq_file *m, loff_t *pos)
1067 int i, stat_items_size;
1069 if (*pos >= ARRAY_SIZE(vmstat_text))
1071 stat_items_size = NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long) +
1072 NR_VM_WRITEBACK_STAT_ITEMS * sizeof(unsigned long);
1074 #ifdef CONFIG_VM_EVENT_COUNTERS
1075 stat_items_size += sizeof(struct vm_event_state);
1078 v = kmalloc(stat_items_size, GFP_KERNEL);
1081 return ERR_PTR(-ENOMEM);
1082 for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
1083 v[i] = global_page_state(i);
1084 v += NR_VM_ZONE_STAT_ITEMS;
1086 global_dirty_limits(v + NR_DIRTY_BG_THRESHOLD,
1087 v + NR_DIRTY_THRESHOLD);
1088 v += NR_VM_WRITEBACK_STAT_ITEMS;
1090 #ifdef CONFIG_VM_EVENT_COUNTERS
1092 v[PGPGIN] /= 2; /* sectors -> kbytes */
1095 return (unsigned long *)m->private + *pos;
1098 static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos)
1101 if (*pos >= ARRAY_SIZE(vmstat_text))
1103 return (unsigned long *)m->private + *pos;
1106 static int vmstat_show(struct seq_file *m, void *arg)
1108 unsigned long *l = arg;
1109 unsigned long off = l - (unsigned long *)m->private;
1111 seq_printf(m, "%s %lu\n", vmstat_text[off], *l);
1115 static void vmstat_stop(struct seq_file *m, void *arg)
1121 static const struct seq_operations vmstat_op = {
1122 .start = vmstat_start,
1123 .next = vmstat_next,
1124 .stop = vmstat_stop,
1125 .show = vmstat_show,
1128 static int vmstat_open(struct inode *inode, struct file *file)
1130 return seq_open(file, &vmstat_op);
1133 static const struct file_operations proc_vmstat_file_operations = {
1134 .open = vmstat_open,
1136 .llseek = seq_lseek,
1137 .release = seq_release,
1139 #endif /* CONFIG_PROC_FS */
1142 static DEFINE_PER_CPU(struct delayed_work, vmstat_work);
1143 int sysctl_stat_interval __read_mostly = HZ;
1145 static void vmstat_update(struct work_struct *w)
1147 refresh_cpu_vm_stats(smp_processor_id());
1148 schedule_delayed_work(&__get_cpu_var(vmstat_work),
1149 round_jiffies_relative(sysctl_stat_interval));
1152 static void __cpuinit start_cpu_timer(int cpu)
1154 struct delayed_work *work = &per_cpu(vmstat_work, cpu);
1156 INIT_DELAYED_WORK_DEFERRABLE(work, vmstat_update);
1157 schedule_delayed_work_on(cpu, work, __round_jiffies_relative(HZ, cpu));
1161 * Use the cpu notifier to insure that the thresholds are recalculated
1164 static int __cpuinit vmstat_cpuup_callback(struct notifier_block *nfb,
1165 unsigned long action,
1168 long cpu = (long)hcpu;
1172 case CPU_ONLINE_FROZEN:
1173 refresh_zone_stat_thresholds();
1174 start_cpu_timer(cpu);
1175 node_set_state(cpu_to_node(cpu), N_CPU);
1177 case CPU_DOWN_PREPARE:
1178 case CPU_DOWN_PREPARE_FROZEN:
1179 cancel_delayed_work_sync(&per_cpu(vmstat_work, cpu));
1180 per_cpu(vmstat_work, cpu).work.func = NULL;
1182 case CPU_DOWN_FAILED:
1183 case CPU_DOWN_FAILED_FROZEN:
1184 start_cpu_timer(cpu);
1187 case CPU_DEAD_FROZEN:
1188 refresh_zone_stat_thresholds();
1196 static struct notifier_block __cpuinitdata vmstat_notifier =
1197 { &vmstat_cpuup_callback, NULL, 0 };
1200 static int __init setup_vmstat(void)
1205 refresh_zone_stat_thresholds();
1206 register_cpu_notifier(&vmstat_notifier);
1208 for_each_online_cpu(cpu)
1209 start_cpu_timer(cpu);
1211 #ifdef CONFIG_PROC_FS
1212 proc_create("buddyinfo", S_IRUGO, NULL, &fragmentation_file_operations);
1213 proc_create("pagetypeinfo", S_IRUGO, NULL, &pagetypeinfo_file_ops);
1214 proc_create("vmstat", S_IRUGO, NULL, &proc_vmstat_file_operations);
1215 proc_create("zoneinfo", S_IRUGO, NULL, &proc_zoneinfo_file_operations);
1219 module_init(setup_vmstat)
1221 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)
1222 #include <linux/debugfs.h>
1224 static struct dentry *extfrag_debug_root;
1227 * Return an index indicating how much of the available free memory is
1228 * unusable for an allocation of the requested size.
1230 static int unusable_free_index(unsigned int order,
1231 struct contig_page_info *info)
1233 /* No free memory is interpreted as all free memory is unusable */
1234 if (info->free_pages == 0)
1238 * Index should be a value between 0 and 1. Return a value to 3
1241 * 0 => no fragmentation
1242 * 1 => high fragmentation
1244 return div_u64((info->free_pages - (info->free_blocks_suitable << order)) * 1000ULL, info->free_pages);
1248 static void unusable_show_print(struct seq_file *m,
1249 pg_data_t *pgdat, struct zone *zone)
1253 struct contig_page_info info;
1255 seq_printf(m, "Node %d, zone %8s ",
1258 for (order = 0; order < MAX_ORDER; ++order) {
1259 fill_contig_page_info(zone, order, &info);
1260 index = unusable_free_index(order, &info);
1261 seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
1268 * Display unusable free space index
1270 * The unusable free space index measures how much of the available free
1271 * memory cannot be used to satisfy an allocation of a given size and is a
1272 * value between 0 and 1. The higher the value, the more of free memory is
1273 * unusable and by implication, the worse the external fragmentation is. This
1274 * can be expressed as a percentage by multiplying by 100.
1276 static int unusable_show(struct seq_file *m, void *arg)
1278 pg_data_t *pgdat = (pg_data_t *)arg;
1280 /* check memoryless node */
1281 if (!node_state(pgdat->node_id, N_HIGH_MEMORY))
1284 walk_zones_in_node(m, pgdat, unusable_show_print);
1289 static const struct seq_operations unusable_op = {
1290 .start = frag_start,
1293 .show = unusable_show,
1296 static int unusable_open(struct inode *inode, struct file *file)
1298 return seq_open(file, &unusable_op);
1301 static const struct file_operations unusable_file_ops = {
1302 .open = unusable_open,
1304 .llseek = seq_lseek,
1305 .release = seq_release,
1308 static void extfrag_show_print(struct seq_file *m,
1309 pg_data_t *pgdat, struct zone *zone)
1314 /* Alloc on stack as interrupts are disabled for zone walk */
1315 struct contig_page_info info;
1317 seq_printf(m, "Node %d, zone %8s ",
1320 for (order = 0; order < MAX_ORDER; ++order) {
1321 fill_contig_page_info(zone, order, &info);
1322 index = __fragmentation_index(order, &info);
1323 seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
1330 * Display fragmentation index for orders that allocations would fail for
1332 static int extfrag_show(struct seq_file *m, void *arg)
1334 pg_data_t *pgdat = (pg_data_t *)arg;
1336 walk_zones_in_node(m, pgdat, extfrag_show_print);
1341 static const struct seq_operations extfrag_op = {
1342 .start = frag_start,
1345 .show = extfrag_show,
1348 static int extfrag_open(struct inode *inode, struct file *file)
1350 return seq_open(file, &extfrag_op);
1353 static const struct file_operations extfrag_file_ops = {
1354 .open = extfrag_open,
1356 .llseek = seq_lseek,
1357 .release = seq_release,
1360 static int __init extfrag_debug_init(void)
1362 extfrag_debug_root = debugfs_create_dir("extfrag", NULL);
1363 if (!extfrag_debug_root)
1366 if (!debugfs_create_file("unusable_index", 0444,
1367 extfrag_debug_root, NULL, &unusable_file_ops))
1370 if (!debugfs_create_file("extfrag_index", 0444,
1371 extfrag_debug_root, NULL, &extfrag_file_ops))
1377 module_init(extfrag_debug_init);