[PATCH] zoned vm counters: convert nr_mapped to per zone counter

[mirror_ubuntu-artful-kernel.git] / mm / vmstat.c

/*
 *  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/config.h>
#include <linux/mm.h>
#include <linux/module.h>

/*
 * Accumulate the page_state information across all CPUs.
 * The result is unavoidably approximate - it can change
 * during and after execution of this function.
 */
DEFINE_PER_CPU(struct page_state, page_states) = {0};

atomic_t nr_pagecache = ATOMIC_INIT(0);
EXPORT_SYMBOL(nr_pagecache);
#ifdef CONFIG_SMP
DEFINE_PER_CPU(long, nr_pagecache_local) = 0;
#endif

static void __get_page_state(struct page_state *ret, int nr, cpumask_t *cpumask)
{
        unsigned cpu;

        memset(ret, 0, nr * sizeof(unsigned long));
        cpus_and(*cpumask, *cpumask, cpu_online_map);

        for_each_cpu_mask(cpu, *cpumask) {
                unsigned long *in;
                unsigned long *out;
                unsigned off;
                unsigned next_cpu;

                in = (unsigned long *)&per_cpu(page_states, cpu);

                next_cpu = next_cpu(cpu, *cpumask);
                if (likely(next_cpu < NR_CPUS))
                        prefetch(&per_cpu(page_states, next_cpu));

                out = (unsigned long *)ret;
                for (off = 0; off < nr; off++)
                        *out++ += *in++;
        }
}

void get_page_state_node(struct page_state *ret, int node)
{
        int nr;
        cpumask_t mask = node_to_cpumask(node);

        nr = offsetof(struct page_state, GET_PAGE_STATE_LAST);
        nr /= sizeof(unsigned long);

        __get_page_state(ret, nr+1, &mask);
}

void get_page_state(struct page_state *ret)
{
        int nr;
        cpumask_t mask = CPU_MASK_ALL;

        nr = offsetof(struct page_state, GET_PAGE_STATE_LAST);
        nr /= sizeof(unsigned long);

        __get_page_state(ret, nr + 1, &mask);
}

void get_full_page_state(struct page_state *ret)
{
        cpumask_t mask = CPU_MASK_ALL;

        __get_page_state(ret, sizeof(*ret) / sizeof(unsigned long), &mask);
}

unsigned long read_page_state_offset(unsigned long offset)
{
        unsigned long ret = 0;
        int cpu;

        for_each_online_cpu(cpu) {
                unsigned long in;

                in = (unsigned long)&per_cpu(page_states, cpu) + offset;
                ret += *((unsigned long *)in);
        }
        return ret;
}

void __mod_page_state_offset(unsigned long offset, unsigned long delta)
{
        void *ptr;

        ptr = &__get_cpu_var(page_states);
        *(unsigned long *)(ptr + offset) += delta;
}
EXPORT_SYMBOL(__mod_page_state_offset);

void mod_page_state_offset(unsigned long offset, unsigned long delta)
{
        unsigned long flags;
        void *ptr;

        local_irq_save(flags);
        ptr = &__get_cpu_var(page_states);
        *(unsigned long *)(ptr + offset) += delta;
        local_irq_restore(flags);
}
EXPORT_SYMBOL(mod_page_state_offset);

void __get_zone_counts(unsigned long *active, unsigned long *inactive,
                        unsigned long *free, struct pglist_data *pgdat)
{
        struct zone *zones = pgdat->node_zones;
        int i;

        *active = 0;
        *inactive = 0;
        *free = 0;
        for (i = 0; i < MAX_NR_ZONES; i++) {
                *active += zones[i].nr_active;
                *inactive += zones[i].nr_inactive;
                *free += zones[i].free_pages;
        }
}

void get_zone_counts(unsigned long *active,
                unsigned long *inactive, unsigned long *free)
{
        struct pglist_data *pgdat;

        *active = 0;
        *inactive = 0;
        *free = 0;
        for_each_online_pgdat(pgdat) {
                unsigned long l, m, n;
                __get_zone_counts(&l, &m, &n, pgdat);
                *active += l;
                *inactive += m;
                *free += n;
        }
}

/*
 * 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>

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;
}

struct seq_operations fragmentation_op = {
        .start  = frag_start,
        .next   = frag_next,
        .stop   = frag_stop,
        .show   = frag_show,
};

static char *vmstat_text[] = {
        /* Zoned VM counters */
        "nr_mapped",

        /* Page state */
        "nr_dirty",
        "nr_writeback",
        "nr_unstable",
        "nr_page_table_pages",
        "nr_slab",

        "pgpgin",
        "pgpgout",
        "pswpin",
        "pswpout",

        "pgalloc_high",
        "pgalloc_normal",
        "pgalloc_dma32",
        "pgalloc_dma",

        "pgfree",
        "pgactivate",
        "pgdeactivate",

        "pgfault",
        "pgmajfault",

        "pgrefill_high",
        "pgrefill_normal",
        "pgrefill_dma32",
        "pgrefill_dma",

        "pgsteal_high",
        "pgsteal_normal",
        "pgsteal_dma32",
        "pgsteal_dma",

        "pgscan_kswapd_high",
        "pgscan_kswapd_normal",
        "pgscan_kswapd_dma32",
        "pgscan_kswapd_dma",

        "pgscan_direct_high",
        "pgscan_direct_normal",
        "pgscan_direct_dma32",
        "pgscan_direct_dma",

        "pginodesteal",
        "slabs_scanned",
        "kswapd_steal",
        "kswapd_inodesteal",
        "pageoutrun",
        "allocstall",

        "pgrotated",
        "nr_bounce",
};

/*
 * 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        active   %lu"
                           "\n        inactive %lu"
                           "\n        scanned  %lu (a: %lu i: %lu)"
                           "\n        spanned  %lu"
                           "\n        present  %lu",
                           zone->free_pages,
                           zone->pages_min,
                           zone->pages_low,
                           zone->pages_high,
                           zone->nr_active,
                           zone->nr_inactive,
                           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++) {
                                if (pageset->pcp[j].count)
                                        break;
                        }
                        if (j == ARRAY_SIZE(pageset->pcp))
                                continue;
                        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_NUMA
                        seq_printf(m,
                                   "\n            numa_hit:       %lu"
                                   "\n            numa_miss:      %lu"
                                   "\n            numa_foreign:   %lu"
                                   "\n            interleave_hit: %lu"
                                   "\n            local_node:     %lu"
                                   "\n            other_node:     %lu",
                                   pageset->numa_hit,
                                   pageset->numa_miss,
                                   pageset->numa_foreign,
                                   pageset->interleave_hit,
                                   pageset->local_node,
                                   pageset->other_node);
#endif
                }
                seq_printf(m,
                           "\n  all_unreclaimable: %u"
                           "\n  prev_priority:     %i"
                           "\n  temp_priority:     %i"
                           "\n  start_pfn:         %lu",
                           zone->all_unreclaimable,
                           zone->prev_priority,
                           zone->temp_priority,
                           zone->zone_start_pfn);
                spin_unlock_irqrestore(&zone->lock, flags);
                seq_putc(m, '\n');
        }
        return 0;
}

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;
        struct page_state *ps;
        int i;

        if (*pos >= ARRAY_SIZE(vmstat_text))
                return NULL;

        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 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;
}

struct seq_operations vmstat_op = {
        .start  = vmstat_start,
        .next   = vmstat_next,
        .stop   = vmstat_stop,
        .show   = vmstat_show,
};

#endif /* CONFIG_PROC_FS */