diff options
Diffstat (limited to 'mm/vmstat.c')
| -rw-r--r-- | mm/vmstat.c | 218 |
1 files changed, 214 insertions, 4 deletions
diff --git a/mm/vmstat.c b/mm/vmstat.c index ad45620..210f9bb 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -3,10 +3,15 @@ * * 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/config.h> #include <linux/mm.h> +#include <linux/module.h> /* * Accumulate the page_state information across all CPUs. @@ -143,6 +148,197 @@ void get_zone_counts(unsigned long *active, } } +/* + * 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 + +#define STAT_THRESHOLD 32 + +/* + * Determine pointer to currently valid differential byte given a zone and + * the item number. + * + * Preemption must be off + */ +static inline s8 *diff_pointer(struct zone *zone, enum zone_stat_item item) +{ + return &zone_pcp(zone, smp_processor_id())->vm_stat_diff[item]; +} + +/* + * For use when we know that interrupts are disabled. + */ +void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item, + int delta) +{ + s8 *p; + long x; + + p = diff_pointer(zone, item); + x = delta + *p; + + if (unlikely(x > STAT_THRESHOLD || x < -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. + * + * 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_page_state(struct page *page, enum zone_stat_item item) +{ + struct zone *zone = page_zone(page); + s8 *p = diff_pointer(zone, item); + + (*p)++; + + if (unlikely(*p > STAT_THRESHOLD)) { + zone_page_state_add(*p, zone, item); + *p = 0; + } +} +EXPORT_SYMBOL(__inc_zone_page_state); + +void __dec_zone_page_state(struct page *page, enum zone_stat_item item) +{ + struct zone *zone = page_zone(page); + s8 *p = diff_pointer(zone, item); + + (*p)--; + + if (unlikely(*p < -STAT_THRESHOLD)) { + zone_page_state_add(*p, zone, item); + *p = 0; + } +} +EXPORT_SYMBOL(__dec_zone_page_state); + +void inc_zone_page_state(struct page *page, enum zone_stat_item item) +{ + unsigned long flags; + struct zone *zone; + s8 *p; + + zone = page_zone(page); + local_irq_save(flags); + p = diff_pointer(zone, item); + + (*p)++; + + if (unlikely(*p > STAT_THRESHOLD)) { + zone_page_state_add(*p, zone, item); + *p = 0; + } + 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; + struct zone *zone; + s8 *p; + + zone = page_zone(page); + local_irq_save(flags); + p = diff_pointer(zone, item); + + (*p)--; + + if (unlikely(*p < -STAT_THRESHOLD)) { + zone_page_state_add(*p, zone, item); + *p = 0; + } + local_irq_restore(flags); +} +EXPORT_SYMBOL(dec_zone_page_state); + +/* + * Update the zone counters for one cpu. + */ +void refresh_cpu_vm_stats(int cpu) +{ + struct zone *zone; + int i; + unsigned long flags; + + for_each_zone(zone) { + struct per_cpu_pageset *pcp; + + pcp = zone_pcp(zone, cpu); + + for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++) + if (pcp->vm_stat_diff[i]) { + local_irq_save(flags); + zone_page_state_add(pcp->vm_stat_diff[i], + zone, i); + pcp->vm_stat_diff[i] = 0; + local_irq_restore(flags); + } + } +} + +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_PROC_FS #include <linux/seq_file.h> @@ -204,6 +400,9 @@ struct seq_operations fragmentation_op = { }; static char *vmstat_text[] = { + /* Zoned VM counters */ + + /* Page state */ "nr_dirty", "nr_writeback", "nr_unstable", @@ -297,6 +496,11 @@ static int zoneinfo_show(struct seq_file *m, void *arg) 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]); @@ -368,19 +572,25 @@ struct seq_operations zoneinfo_op = { static void *vmstat_start(struct seq_file *m, loff_t *pos) { + unsigned long *v; struct page_state *ps; + int i; if (*pos >= ARRAY_SIZE(vmstat_text)) return NULL; - ps = kmalloc(sizeof(*ps), GFP_KERNEL); - m->private = ps; - if (!ps) + v = kmalloc(NR_VM_ZONE_STAT_ITEMS * sizeof(unsigned long) + + sizeof(*ps), GFP_KERNEL); + 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); + ps = (struct page_state *)(v + NR_VM_ZONE_STAT_ITEMS); get_full_page_state(ps); ps->pgpgin /= 2; /* sectors -> kbytes */ ps->pgpgout /= 2; - return (unsigned long *)ps + *pos; + return v + *pos; } static void *vmstat_next(struct seq_file *m, void *arg, loff_t *pos) |