[ALSA] Add ALSA support for the SEGA Dreamcast PCM device
[safe/jmp/linux-2.6] / mm / vmstat.c
index 4800091..fadf791 100644 (file)
  *             Christoph Lameter <christoph@lameter.com>
  */
 
-#include <linux/config.h>
 #include <linux/mm.h>
 #include <linux/module.h>
+#include <linux/cpu.h>
+#include <linux/sched.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);
-}
+#ifdef CONFIG_VM_EVENT_COUNTERS
+DEFINE_PER_CPU(struct vm_event_state, vm_event_states) = {{0}};
+EXPORT_PER_CPU_SYMBOL(vm_event_states);
 
-void get_page_state(struct page_state *ret)
+static void sum_vm_events(unsigned long *ret, cpumask_t *cpumask)
 {
-       int nr;
-       cpumask_t mask = CPU_MASK_ALL;
+       int cpu = 0;
+       int i;
 
-       nr = offsetof(struct page_state, GET_PAGE_STATE_LAST);
-       nr /= sizeof(unsigned long);
+       memset(ret, 0, NR_VM_EVENT_ITEMS * sizeof(unsigned long));
 
-       __get_page_state(ret, nr + 1, &mask);
-}
+       cpu = first_cpu(*cpumask);
+       while (cpu < NR_CPUS) {
+               struct vm_event_state *this = &per_cpu(vm_event_states, cpu);
 
-void get_full_page_state(struct page_state *ret)
-{
-       cpumask_t mask = CPU_MASK_ALL;
+               cpu = next_cpu(cpu, *cpumask);
 
-       __get_page_state(ret, sizeof(*ret) / sizeof(unsigned long), &mask);
-}
+               if (cpu < NR_CPUS)
+                       prefetch(&per_cpu(vm_event_states, cpu));
 
-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);
+               for (i = 0; i < NR_VM_EVENT_ITEMS; i++)
+                       ret[i] += this->event[i];
        }
-       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)
+/*
+ * 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)
 {
-       unsigned long flags;
-       void *ptr;
-
-       local_irq_save(flags);
-       ptr = &__get_cpu_var(page_states);
-       *(unsigned long *)(ptr + offset) += delta;
-       local_irq_restore(flags);
+       sum_vm_events(ret, &cpu_online_map);
 }
-EXPORT_SYMBOL(mod_page_state_offset);
+EXPORT_SYMBOL_GPL(all_vm_events);
 
-void __get_zone_counts(unsigned long *active, unsigned long *inactive,
-                       unsigned long *free, struct pglist_data *pgdat)
+#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 zone *zones = pgdat->node_zones;
+       struct vm_event_state *fold_state = &per_cpu(vm_event_states, cpu);
        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;
+       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 */
 
-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;
-       }
-}
+#endif /* CONFIG_VM_EVENT_COUNTERS */
 
 /*
  * Manage combined zone based / global counters
@@ -158,17 +82,72 @@ EXPORT_SYMBOL(vm_stat);
 
 #ifdef CONFIG_SMP
 
-#define STAT_THRESHOLD 32
+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;
+}
 
 /*
- * Determine pointer to currently valid differential byte given a zone and
- * the item number.
- *
- * Preemption must be off
+ * Refresh the thresholds for each zone.
  */
-static inline s8 *diff_pointer(struct zone *zone, enum zone_stat_item item)
+static void refresh_zone_stat_thresholds(void)
 {
-       return &zone_pcp(zone, smp_processor_id())->vm_stat_diff[item];
+       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;
+       }
 }
 
 /*
@@ -177,17 +156,16 @@ static inline s8 *diff_pointer(struct zone *zone, enum zone_stat_item item)
 void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
                                int delta)
 {
-       s8 *p;
+       struct per_cpu_pageset *pcp = zone_pcp(zone, smp_processor_id());
+       s8 *p = pcp->vm_stat_diff + item;
        long x;
 
-       p = diff_pointer(zone, item);
        x = delta + *p;
 
-       if (unlikely(x > STAT_THRESHOLD || x < -STAT_THRESHOLD)) {
+       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);
@@ -216,10 +194,12 @@ EXPORT_SYMBOL(mod_zone_page_state);
  * 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
@@ -227,50 +207,65 @@ EXPORT_SYMBOL(mod_zone_page_state);
  * 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)
+void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
 {
-       struct zone *zone = page_zone(page);
-       s8 *p = diff_pointer(zone, item);
+       struct per_cpu_pageset *pcp = zone_pcp(zone, smp_processor_id());
+       s8 *p = pcp->vm_stat_diff + item;
 
        (*p)++;
 
-       if (unlikely(*p > STAT_THRESHOLD)) {
-               zone_page_state_add(*p, zone, item);
-               *p = 0;
+       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_page_state(struct page *page, enum zone_stat_item item)
+void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
 {
-       struct zone *zone = page_zone(page);
-       s8 *p = diff_pointer(zone, item);
+       struct per_cpu_pageset *pcp = zone_pcp(zone, smp_processor_id());
+       s8 *p = pcp->vm_stat_diff + item;
 
        (*p)--;
 
-       if (unlikely(*p < -STAT_THRESHOLD)) {
-               zone_page_state_add(*p, zone, item);
-               *p = 0;
+       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;
-       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;
-       }
+       __inc_zone_state(zone, item);
        local_irq_restore(flags);
 }
 EXPORT_SYMBOL(inc_zone_page_state);
@@ -278,25 +273,26 @@ 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;
-       }
+       __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)
 {
@@ -305,18 +301,54 @@ void refresh_cpu_vm_stats(int cpu)
        unsigned long flags;
 
        for_each_zone(zone) {
-               struct per_cpu_pageset *pcp;
+               struct per_cpu_pageset *p;
+
+               if (!populated_zone(zone))
+                       continue;
 
-               pcp = zone_pcp(zone, cpu);
+               p = zone_pcp(zone, cpu);
 
                for (i = 0; i < NR_VM_ZONE_STAT_ITEMS; i++)
-                       if (pcp->vm_stat_diff[i]) {
+                       if (p->vm_stat_diff[i]) {
                                local_irq_save(flags);
-                               zone_page_state_add(pcp->vm_stat_diff[i],
+                               zone_page_state_add(p->vm_stat_diff[i],
                                        zone, i);
-                               pcp->vm_stat_diff[i] = 0;
+                               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
        }
 }
 
@@ -339,6 +371,28 @@ 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>
@@ -392,33 +446,67 @@ static int frag_show(struct seq_file *m, void *arg)
        return 0;
 }
 
-struct seq_operations fragmentation_op = {
+const struct seq_operations fragmentation_op = {
        .start  = frag_start,
        .next   = frag_next,
        .stop   = frag_stop,
        .show   = frag_show,
 };
 
-static char *vmstat_text[] = {
+#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",
-
-       /* Page state */
+       "nr_file_pages",
        "nr_dirty",
        "nr_writeback",
-       "nr_unstable",
+       "nr_slab_reclaimable",
+       "nr_slab_unreclaimable",
        "nr_page_table_pages",
-       "nr_slab",
+       "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",
 
-       "pgalloc_high",
-       "pgalloc_normal",
-       "pgalloc_dma32",
-       "pgalloc_dma",
+       TEXTS_FOR_ZONES("pgalloc")
 
        "pgfree",
        "pgactivate",
@@ -427,25 +515,10 @@ static char *vmstat_text[] = {
        "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",
+       TEXTS_FOR_ZONES("pgrefill")
+       TEXTS_FOR_ZONES("pgsteal")
+       TEXTS_FOR_ZONES("pgscan_kswapd")
+       TEXTS_FOR_ZONES("pgscan_direct")
 
        "pginodesteal",
        "slabs_scanned",
@@ -455,7 +528,7 @@ static char *vmstat_text[] = {
        "allocstall",
 
        "pgrotated",
-       "nr_bounce",
+#endif
 };
 
 /*
@@ -481,17 +554,13 @@ static int zoneinfo_show(struct seq_file *m, void *arg)
                           "\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_page_state(zone, NR_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,
@@ -515,12 +584,6 @@ static int zoneinfo_show(struct seq_file *m, void *arg)
 
                        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"
@@ -531,30 +594,17 @@ static int zoneinfo_show(struct seq_file *m, void *arg)
                                           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);
+#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  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');
@@ -562,7 +612,7 @@ static int zoneinfo_show(struct seq_file *m, void *arg)
        return 0;
 }
 
-struct seq_operations zoneinfo_op = {
+const struct seq_operations zoneinfo_op = {
        .start  = frag_start, /* iterate over all zones. The same as in
                               * fragmentation. */
        .next   = frag_next,
@@ -573,23 +623,32 @@ struct seq_operations zoneinfo_op = {
 static void *vmstat_start(struct seq_file *m, loff_t *pos)
 {
        unsigned long *v;
-       struct page_state *ps;
+#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(*ps), GFP_KERNEL);
+                       + 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);
-       ps = (struct page_state *)(v + NR_VM_ZONE_STAT_ITEMS);
-       get_full_page_state(ps);
-       ps->pgpgin /= 2;                /* sectors -> kbytes */
-       ps->pgpgout /= 2;
+#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;
 }
 
@@ -616,7 +675,7 @@ static void vmstat_stop(struct seq_file *m, void *arg)
        m->private = NULL;
 }
 
-struct seq_operations vmstat_op = {
+const struct seq_operations vmstat_op = {
        .start  = vmstat_start,
        .next   = vmstat_next,
        .stop   = vmstat_stop,
@@ -625,3 +684,72 @@ struct seq_operations vmstat_op = {
 
 #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