/* * linux/mm/vmstat.c * * Manages VM statistics * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds * * zoned VM statistics * Copyright (C) 2006 Silicon Graphics, Inc., * Christoph Lameter <christoph@lameter.com> */ #include <linux/mm.h> #include <linux/err.h> #include <linux/module.h> #include <linux/cpu.h> #include <linux/sched.h> #ifdef CONFIG_VM_EVENT_COUNTERS DEFINE_PER_CPU(struct vm_event_state, vm_event_states) = {{0}}; EXPORT_PER_CPU_SYMBOL(vm_event_states); static void sum_vm_events(unsigned long *ret, cpumask_t *cpumask) { int cpu = 0; int i; memset(ret, 0, NR_VM_EVENT_ITEMS * sizeof(unsigned long)); cpu = first_cpu(*cpumask); while (cpu < NR_CPUS) { struct vm_event_state *this = &per_cpu(vm_event_states, cpu); cpu = next_cpu(cpu, *cpumask); if (cpu < NR_CPUS) prefetch(&per_cpu(vm_event_states, cpu)); for (i = 0; i < NR_VM_EVENT_ITEMS; i++) ret[i] += this->event[i]; } } /* * Accumulate the vm event counters across all CPUs. * The result is unavoidably approximate - it can change * during and after execution of this function. */ void all_vm_events(unsigned long *ret) { sum_vm_events(ret, &cpu_online_map); } EXPORT_SYMBOL_GPL(all_vm_events); #ifdef CONFIG_HOTPLUG /* * Fold the foreign cpu events into our own. * * This is adding to the events on one processor * but keeps the global counts constant. */ void vm_events_fold_cpu(int cpu) { struct vm_event_state *fold_state = &per_cpu(vm_event_states, cpu); int i; for (i = 0; i < NR_VM_EVENT_ITEMS; i++) { count_vm_events(i, fold_state->event[i]); fold_state->event[i] = 0; } } #endif /* CONFIG_HOTPLUG */ #endif /* CONFIG_VM_EVENT_COUNTERS */ /* * Manage combined zone based / global counters * * vm_stat contains the global counters */ atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS]; EXPORT_SYMBOL(vm_stat); #ifdef CONFIG_SMP static int calculate_threshold(struct zone *zone) { int threshold; int mem; /* memory in 128 MB units */ /* * The threshold scales with the number of processors and the amount * of memory per zone. More memory means that we can defer updates for * longer, more processors could lead to more contention. * fls() is used to have a cheap way of logarithmic scaling. * * Some sample thresholds: * * Threshold Processors (fls) Zonesize fls(mem+1) * ------------------------------------------------------------------ * 8 1 1 0.9-1 GB 4 * 16 2 2 0.9-1 GB 4 * 20 2 2 1-2 GB 5 * 24 2 2 2-4 GB 6 * 28 2 2 4-8 GB 7 * 32 2 2 8-16 GB 8 * 4 2 2 <128M 1 * 30 4 3 2-4 GB 5 * 48 4 3 8-16 GB 8 * 32 8 4 1-2 GB 4 * 32 8 4 0.9-1GB 4 * 10 16 5 <128M 1 * 40 16 5 900M 4 * 70 64 7 2-4 GB 5 * 84 64 7 4-8 GB 6 * 108 512 9 4-8 GB 6 * 125 1024 10 8-16 GB 8 * 125 1024 10 16-32 GB 9 */ mem = zone->present_pages >> (27 - PAGE_SHIFT); threshold = 2 * fls(num_online_cpus()) * (1 + fls(mem)); /* * Maximum threshold is 125 */ threshold = min(125, threshold); return threshold; } /* * Refresh the thresholds for each zone. */ static void refresh_zone_stat_thresholds(void) { struct zone *zone; int cpu; int threshold; for_each_zone(zone) { if (!zone->present_pages) continue; threshold = calculate_threshold(zone); for_each_online_cpu(cpu) zone_pcp(zone, cpu)->stat_threshold = threshold; } } /* * For use when we know that interrupts are disabled. */ void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item, int delta) { struct per_cpu_pageset *pcp = zone_pcp(zone, smp_processor_id()); s8 *p = pcp->vm_stat_diff + item; long x; x = delta + *p; if (unlikely(x > pcp->stat_threshold || x < -pcp->stat_threshold)) { zone_page_state_add(x, zone, item); x = 0; } *p = x; } EXPORT_SYMBOL(__mod_zone_page_state); /* * For an unknown interrupt state */ void mod_zone_page_state(struct zone *zone, enum zone_stat_item item, int delta) { unsigned long flags; local_irq_save(flags); __mod_zone_page_state(zone, item, delta); local_irq_restore(flags); } EXPORT_SYMBOL(mod_zone_page_state); /* * Optimized increment and decrement functions. * * These are only for a single page and therefore can take a struct page * * argument instead of struct zone *. This allows the inclusion of the code * generated for page_zone(page) into the optimized functions. * * No overflow check is necessary and therefore the differential can be * incremented or decremented in place which may allow the compilers to * generate better code. * The increment or decrement is known and therefore one boundary check can * be omitted. * * NOTE: These functions are very performance sensitive. Change only * with care. * * Some processors have inc/dec instructions that are atomic vs an interrupt. * However, the code must first determine the differential location in a zone * based on the processor number and then inc/dec the counter. There is no * guarantee without disabling preemption that the processor will not change * in between and therefore the atomicity vs. interrupt cannot be exploited * in a useful way here. */ void __inc_zone_state(struct zone *zone, enum zone_stat_item item) { struct per_cpu_pageset *pcp = zone_pcp(zone, smp_processor_id()); s8 *p = pcp->vm_stat_diff + item; (*p)++; if (unlikely(*p > pcp->stat_threshold)) { int overstep = pcp->stat_threshold / 2; zone_page_state_add(*p + overstep, zone, item); *p = -overstep; } } void __inc_zone_page_state(struct page *page, enum zone_stat_item item) { __inc_zone_state(page_zone(page), item); } EXPORT_SYMBOL(__inc_zone_page_state); void __dec_zone_state(struct zone *zone, enum zone_stat_item item) { struct per_cpu_pageset *pcp = zone_pcp(zone, smp_processor_id()); s8 *p = pcp->vm_stat_diff + item; (*p)--; if (unlikely(*p < - pcp->stat_threshold)) { int overstep = pcp->stat_threshold / 2; zone_page_state_add(*p - overstep, zone, item); *p = overstep; } } void __dec_zone_page_state(struct page *page, enum zone_stat_item item) { __dec_zone_state(page_zone(page), item); } EXPORT_SYMBOL(__dec_zone_page_state); void inc_zone_state(struct zone *zone, enum zone_stat_item item) { unsigned long flags; local_irq_save(flags); __inc_zone_state(zone, item); local_irq_restore(flags); } void inc_zone_page_state(struct page *page, enum zone_stat_item item) { unsigned long flags; struct zone *zone; zone = page_zone(page); local_irq_save(flags); __inc_zone_state(zone, item); local_irq_restore(flags); } EXPORT_SYMBOL(inc_zone_page_state); void dec_zone_page_state(struct page *page, enum zone_stat_item item) { unsigned long flags; local_irq_save(flags); __dec_zone_page_state(page, item); local_irq_restore(flags); } EXPORT_SYMBOL(dec_zone_page_state); /* * Update the zone counters for one cpu. * * Note that refresh_cpu_vm_stats strives to only access * node local memory. The per cpu pagesets on remote zones are placed * in the memory local to the processor using that pageset. So the * loop over all zones will access a series of cachelines local to * the processor. * * The call to zone_page_state_add updates the cachelines with the * statistics in the remote zone struct as well as the global cachelines * with the global counters. These could cause remote node cache line * bouncing and will have to be only done when necessary. */ void refresh_cpu_vm_stats(int cpu) { struct zone *zone; int i; unsigned long flags; for_each_zone(zone) { struct per_cpu_pageset *p; if (!populated_zone(zone)) continue; p = zone_pcp(zone, cpu); for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) if (p->vm_stat_diff[i]) { local_irq_save(flags); zone_page_state_add(p->vm_stat_diff[i], zone, i); p->vm_stat_diff[i] = 0; #ifdef CONFIG_NUMA /* 3 seconds idle till flush */ p->expire = 3; #endif local_irq_restore(flags); } #ifdef CONFIG_NUMA /* * Deal with draining the remote pageset of this * processor * * Check if there are pages remaining in this pageset * if not then there is nothing to expire. */ if (!p->expire || (!p->pcp[0].count && !p->pcp[1].count)) continue; /* * We never drain zones local to this processor. */ if (zone_to_nid(zone) == numa_node_id()) { p->expire = 0; continue; } p->expire--; if (p->expire) continue; if (p->pcp[0].count) drain_zone_pages(zone, p->pcp + 0); if (p->pcp[1].count) drain_zone_pages(zone, p->pcp + 1); #endif } } static void __refresh_cpu_vm_stats(void *dummy) { refresh_cpu_vm_stats(smp_processor_id()); } /* * Consolidate all counters. * * Note that the result is less inaccurate but still inaccurate * if concurrent processes are allowed to run. */ void refresh_vm_stats(void) { on_each_cpu(__refresh_cpu_vm_stats, NULL, 0, 1); } EXPORT_SYMBOL(refresh_vm_stats); #endif #ifdef CONFIG_NUMA /* * zonelist = the list of zones passed to the allocator * z = the zone from which the allocation occurred. * * Must be called with interrupts disabled. */ void zone_statistics(struct zonelist *zonelist, struct zone *z) { if (z->zone_pgdat == zonelist->zones[0]->zone_pgdat) { __inc_zone_state(z, NUMA_HIT); } else { __inc_zone_state(z, NUMA_MISS); __inc_zone_state(zonelist->zones[0], NUMA_FOREIGN); } if (z->node == numa_node_id()) __inc_zone_state(z, NUMA_LOCAL); else __inc_zone_state(z, NUMA_OTHER); } #endif #ifdef CONFIG_PROC_FS #include <linux/seq_file.h> static void *frag_start(struct seq_file *m, loff_t *pos) { pg_data_t *pgdat; loff_t node = *pos; for (pgdat = first_online_pgdat(); pgdat && node; pgdat = next_online_pgdat(pgdat)) --node; return pgdat; } static void *frag_next(struct seq_file *m, void *arg, loff_t *pos) { pg_data_t *pgdat = (pg_data_t *)arg; (*pos)++; return next_online_pgdat(pgdat); } static void frag_stop(struct seq_file *m, void *arg) { } /* * This walks the free areas for each zone. */ static int frag_show(struct seq_file *m, void *arg) { pg_data_t *pgdat = (pg_data_t *)arg; struct zone *zone; struct zone *node_zones = pgdat->node_zones; unsigned long flags; int order; for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) { if (!populated_zone(zone)) continue; spin_lock_irqsave(&zone->lock, flags); seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name); for (order = 0; order < MAX_ORDER; ++order) seq_printf(m, "%6lu ", zone->free_area[order].nr_free); spin_unlock_irqrestore(&zone->lock, flags); seq_putc(m, '\n'); } return 0; } const struct seq_operations fragmentation_op = { .start = frag_start, .next = frag_next, .stop = frag_stop, .show = frag_show, }; #ifdef CONFIG_ZONE_DMA #define TEXT_FOR_DMA(xx) xx "_dma", #else #define TEXT_FOR_DMA(xx) #endif #ifdef CONFIG_ZONE_DMA32 #define TEXT_FOR_DMA32(xx) xx "_dma32", #else #define TEXT_FOR_DMA32(xx) #endif #ifdef CONFIG_HIGHMEM #define TEXT_FOR_HIGHMEM(xx) xx "_high", #else #define TEXT_FOR_HIGHMEM(xx) #endif #define TEXTS_FOR_ZONES(xx) TEXT_FOR_DMA(xx) TEXT_FOR_DMA32(xx) xx "_normal", \ TEXT_FOR_HIGHMEM(xx) xx "_movable", static const char * const vmstat_text[] = { /* Zoned VM counters */ "nr_free_pages", "nr_inactive", "nr_active", "nr_anon_pages", "nr_mapped", "nr_file_pages", "nr_dirty", "nr_writeback", "nr_slab_reclaimable", "nr_slab_unreclaimable", "nr_page_table_pages", "nr_unstable", "nr_bounce", "nr_vmscan_write", #ifdef CONFIG_NUMA "numa_hit", "numa_miss", "numa_foreign", "numa_interleave", "numa_local", "numa_other", #endif #ifdef CONFIG_VM_EVENT_COUNTERS "pgpgin", "pgpgout", "pswpin", "pswpout", TEXTS_FOR_ZONES("pgalloc") "pgfree", "pgactivate", "pgdeactivate", "pgfault", "pgmajfault", TEXTS_FOR_ZONES("pgrefill") TEXTS_FOR_ZONES("pgsteal") TEXTS_FOR_ZONES("pgscan_kswapd") TEXTS_FOR_ZONES("pgscan_direct") "pginodesteal", "slabs_scanned", "kswapd_steal", "kswapd_inodesteal", "pageoutrun", "allocstall", "pgrotated", #endif }; /* * Output information about zones in @pgdat. */ static int zoneinfo_show(struct seq_file *m, void *arg) { pg_data_t *pgdat = arg; struct zone *zone; struct zone *node_zones = pgdat->node_zones; unsigned long flags; for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; zone++) { int i; if (!populated_zone(zone)) continue; spin_lock_irqsave(&zone->lock, flags); seq_printf(m, "Node %d, zone %8s", pgdat->node_id, zone->name); seq_printf(m, "\n pages free %lu" "\n min %lu" "\n low %lu" "\n high %lu" "\n scanned %lu (a: %lu i: %lu)" "\n spanned %lu" "\n present %lu", zone_page_state(zone, NR_FREE_PAGES), zone->pages_min, zone->pages_low, zone->pages_high, zone->pages_scanned, zone->nr_scan_active, zone->nr_scan_inactive, zone->spanned_pages, zone->present_pages); for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) seq_printf(m, "\n %-12s %lu", vmstat_text[i], zone_page_state(zone, i)); seq_printf(m, "\n protection: (%lu", zone->lowmem_reserve[0]); for (i = 1; i < ARRAY_SIZE(zone->lowmem_reserve); i++) seq_printf(m, ", %lu", zone->lowmem_reserve[i]); seq_printf(m, ")" "\n pagesets"); for_each_online_cpu(i) { struct per_cpu_pageset *pageset; int j; pageset = zone_pcp(zone, i); for (j = 0; j < ARRAY_SIZE(pageset->pcp); j++) { seq_printf(m, "\n cpu: %i pcp: %i" "\n count: %i" "\n high: %i" "\n batch: %i", i, j, pageset->pcp[j].count, pageset->pcp[j].high, pageset->pcp[j].batch); } #ifdef CONFIG_SMP seq_printf(m, "\n vm stats threshold: %d", pageset->stat_threshold); #endif } seq_printf(m, "\n all_unreclaimable: %u" "\n prev_priority: %i" "\n start_pfn: %lu", zone->all_unreclaimable, zone->prev_priority, zone->zone_start_pfn); spin_unlock_irqrestore(&zone->lock, flags); seq_putc(m, '\n'); } return 0; } const struct seq_operations zoneinfo_op = { .start = frag_start, /* iterate over all zones. The same as in * fragmentation. */ .next = frag_next, .stop = frag_stop, .show = zoneinfo_show, }; static void *vmstat_start(struct seq_file *m, loff_t *pos) { unsigned long *v; #ifdef CONFIG_VM_EVENT_COUNTERS unsigned long *e; #endif int i; if (*pos >= ARRAY_SIZE(vmstat_text)) return NULL; #ifdef CONFIG_VM_EVENT_COUNTERS v = kmalloc(NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long) + sizeof(struct vm_event_state), GFP_KERNEL); #else v = kmalloc(NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long), GFP_KERNEL); #endif m->private = v; if (!v) return ERR_PTR(-ENOMEM); for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) v[i] = global_page_state(i); #ifdef CONFIG_VM_EVENT_COUNTERS e = v + NR_VM_ZONE_STAT_ITEMS; all_vm_events(e); e[PGPGIN] /= 2; /* sectors -> kbytes */ e[PGPGOUT] /= 2; #endif return v + *pos; } static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos) { (*pos)++; if (*pos >= ARRAY_SIZE(vmstat_text)) return NULL; return (unsigned long *)m->private + *pos; } static int vmstat_show(struct seq_file *m, void *arg) { unsigned long *l = arg; unsigned long off = l - (unsigned long *)m->private; seq_printf(m, "%s %lu\n", vmstat_text[off], *l); return 0; } static void vmstat_stop(struct seq_file *m, void *arg) { kfree(m->private); m->private = NULL; } const struct seq_operations vmstat_op = { .start = vmstat_start, .next = vmstat_next, .stop = vmstat_stop, .show = vmstat_show, }; #endif /* CONFIG_PROC_FS */ #ifdef CONFIG_SMP static DEFINE_PER_CPU(struct delayed_work, vmstat_work); int sysctl_stat_interval __read_mostly = HZ; static void vmstat_update(struct work_struct *w) { refresh_cpu_vm_stats(smp_processor_id()); schedule_delayed_work(&__get_cpu_var(vmstat_work), sysctl_stat_interval); } static void __devinit start_cpu_timer(int cpu) { struct delayed_work *vmstat_work = &per_cpu(vmstat_work, cpu); INIT_DELAYED_WORK_DEFERRABLE(vmstat_work, vmstat_update); schedule_delayed_work_on(cpu, vmstat_work, HZ + cpu); } /* * Use the cpu notifier to insure that the thresholds are recalculated * when necessary. */ static int __cpuinit vmstat_cpuup_callback(struct notifier_block *nfb, unsigned long action, void *hcpu) { long cpu = (long)hcpu; switch (action) { case CPU_ONLINE: case CPU_ONLINE_FROZEN: start_cpu_timer(cpu); break; case CPU_DOWN_PREPARE: case CPU_DOWN_PREPARE_FROZEN: cancel_rearming_delayed_work(&per_cpu(vmstat_work, cpu)); per_cpu(vmstat_work, cpu).work.func = NULL; break; case CPU_DOWN_FAILED: case CPU_DOWN_FAILED_FROZEN: start_cpu_timer(cpu); break; case CPU_DEAD: case CPU_DEAD_FROZEN: refresh_zone_stat_thresholds(); break; default: break; } return NOTIFY_OK; } static struct notifier_block __cpuinitdata vmstat_notifier = { &vmstat_cpuup_callback, NULL, 0 }; int __init setup_vmstat(void) { int cpu; refresh_zone_stat_thresholds(); register_cpu_notifier(&vmstat_notifier); for_each_online_cpu(cpu) start_cpu_timer(cpu); return 0; } module_init(setup_vmstat) #endif