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-rw-r--r--mm/vmstat.c218
1 files changed, 214 insertions, 4 deletions
diff --git a/mm/vmstat.c b/mm/vmstat.c
index ad456202ff1a..210f9bbbb04f 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)