![Christoph Lameter](/assets/img/avatar_default.png)
vmstat is currently using the cache reaper to periodically bring the statistics up to date. The cache reaper does only exists in SLUB as a way to provide compatibility with SLAB. This patch removes the vmstat calls from the slab allocators and provides its own handling. The advantage is also that we can use a different frequency for the updates. Refreshing vm stats is a pretty fast job so we can run this every second and stagger this by only one tick. This will lead to some overlap in large systems. F.e a system running at 250 HZ with 1024 processors will have 4 vm updates occurring at once. However, the vm stats update only accesses per node information. It is only necessary to stagger the vm statistics updates per processor in each node. Vm counter updates occurring on distant nodes will not cause cacheline contention. We could implement an alternate approach that runs the first processor on each node at the second and then each of the other processor on a node on a subsequent tick. That may be useful to keep a large amount of the second free of timer activity. Maybe the timer folks will have some feedback on this one? [jirislaby@gmail.com: add missing break] Cc: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Jiri Slaby <jirislaby@gmail.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
264 lines
6.5 KiB
C
264 lines
6.5 KiB
C
#ifndef _LINUX_VMSTAT_H
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#define _LINUX_VMSTAT_H
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#include <linux/types.h>
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#include <linux/percpu.h>
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#include <linux/mm.h>
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#include <linux/mmzone.h>
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#include <asm/atomic.h>
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#ifdef CONFIG_ZONE_DMA
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#define DMA_ZONE(xx) xx##_DMA,
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#else
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#define DMA_ZONE(xx)
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#endif
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#ifdef CONFIG_ZONE_DMA32
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#define DMA32_ZONE(xx) xx##_DMA32,
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#else
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#define DMA32_ZONE(xx)
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#endif
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#ifdef CONFIG_HIGHMEM
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#define HIGHMEM_ZONE(xx) , xx##_HIGH
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#else
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#define HIGHMEM_ZONE(xx)
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#endif
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#define FOR_ALL_ZONES(xx) DMA_ZONE(xx) DMA32_ZONE(xx) xx##_NORMAL HIGHMEM_ZONE(xx)
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enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
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FOR_ALL_ZONES(PGALLOC),
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PGFREE, PGACTIVATE, PGDEACTIVATE,
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PGFAULT, PGMAJFAULT,
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FOR_ALL_ZONES(PGREFILL),
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FOR_ALL_ZONES(PGSTEAL),
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FOR_ALL_ZONES(PGSCAN_KSWAPD),
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FOR_ALL_ZONES(PGSCAN_DIRECT),
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PGINODESTEAL, SLABS_SCANNED, KSWAPD_STEAL, KSWAPD_INODESTEAL,
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PAGEOUTRUN, ALLOCSTALL, PGROTATED,
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NR_VM_EVENT_ITEMS
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};
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#ifdef CONFIG_VM_EVENT_COUNTERS
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/*
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* Light weight per cpu counter implementation.
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*
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* Counters should only be incremented and no critical kernel component
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* should rely on the counter values.
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*
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* Counters are handled completely inline. On many platforms the code
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* generated will simply be the increment of a global address.
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*/
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struct vm_event_state {
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unsigned long event[NR_VM_EVENT_ITEMS];
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};
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DECLARE_PER_CPU(struct vm_event_state, vm_event_states);
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static inline void __count_vm_event(enum vm_event_item item)
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{
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__get_cpu_var(vm_event_states).event[item]++;
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}
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static inline void count_vm_event(enum vm_event_item item)
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{
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get_cpu_var(vm_event_states).event[item]++;
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put_cpu();
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}
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static inline void __count_vm_events(enum vm_event_item item, long delta)
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{
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__get_cpu_var(vm_event_states).event[item] += delta;
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}
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static inline void count_vm_events(enum vm_event_item item, long delta)
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{
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get_cpu_var(vm_event_states).event[item] += delta;
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put_cpu();
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}
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extern void all_vm_events(unsigned long *);
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#ifdef CONFIG_HOTPLUG
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extern void vm_events_fold_cpu(int cpu);
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#else
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static inline void vm_events_fold_cpu(int cpu)
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{
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}
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#endif
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#else
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/* Disable counters */
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static inline void count_vm_event(enum vm_event_item item)
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{
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}
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static inline void count_vm_events(enum vm_event_item item, long delta)
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{
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}
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static inline void __count_vm_event(enum vm_event_item item)
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{
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}
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static inline void __count_vm_events(enum vm_event_item item, long delta)
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{
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}
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static inline void all_vm_events(unsigned long *ret)
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{
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}
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static inline void vm_events_fold_cpu(int cpu)
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{
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}
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#endif /* CONFIG_VM_EVENT_COUNTERS */
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#define __count_zone_vm_events(item, zone, delta) \
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__count_vm_events(item##_NORMAL - ZONE_NORMAL + \
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zone_idx(zone), delta)
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/*
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* Zone based page accounting with per cpu differentials.
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*/
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extern atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS];
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static inline void zone_page_state_add(long x, struct zone *zone,
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enum zone_stat_item item)
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{
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atomic_long_add(x, &zone->vm_stat[item]);
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atomic_long_add(x, &vm_stat[item]);
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}
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static inline unsigned long global_page_state(enum zone_stat_item item)
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{
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long x = atomic_long_read(&vm_stat[item]);
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#ifdef CONFIG_SMP
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if (x < 0)
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x = 0;
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#endif
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return x;
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}
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static inline unsigned long zone_page_state(struct zone *zone,
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enum zone_stat_item item)
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{
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long x = atomic_long_read(&zone->vm_stat[item]);
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#ifdef CONFIG_SMP
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if (x < 0)
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x = 0;
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#endif
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return x;
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}
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#ifdef CONFIG_NUMA
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/*
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* Determine the per node value of a stat item. This function
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* is called frequently in a NUMA machine, so try to be as
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* frugal as possible.
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*/
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static inline unsigned long node_page_state(int node,
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enum zone_stat_item item)
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{
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struct zone *zones = NODE_DATA(node)->node_zones;
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return
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#ifdef CONFIG_ZONE_DMA
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zone_page_state(&zones[ZONE_DMA], item) +
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#endif
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#ifdef CONFIG_ZONE_DMA32
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zone_page_state(&zones[ZONE_DMA32], item) +
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#endif
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#ifdef CONFIG_HIGHMEM
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zone_page_state(&zones[ZONE_HIGHMEM], item) +
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#endif
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zone_page_state(&zones[ZONE_NORMAL], item);
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}
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extern void zone_statistics(struct zonelist *, struct zone *);
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#else
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#define node_page_state(node, item) global_page_state(item)
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#define zone_statistics(_zl,_z) do { } while (0)
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#endif /* CONFIG_NUMA */
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#define __add_zone_page_state(__z, __i, __d) \
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__mod_zone_page_state(__z, __i, __d)
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#define __sub_zone_page_state(__z, __i, __d) \
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__mod_zone_page_state(__z, __i,-(__d))
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#define add_zone_page_state(__z, __i, __d) mod_zone_page_state(__z, __i, __d)
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#define sub_zone_page_state(__z, __i, __d) mod_zone_page_state(__z, __i, -(__d))
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static inline void zap_zone_vm_stats(struct zone *zone)
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{
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memset(zone->vm_stat, 0, sizeof(zone->vm_stat));
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}
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extern void inc_zone_state(struct zone *, enum zone_stat_item);
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#ifdef CONFIG_SMP
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void __mod_zone_page_state(struct zone *, enum zone_stat_item item, int);
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void __inc_zone_page_state(struct page *, enum zone_stat_item);
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void __dec_zone_page_state(struct page *, enum zone_stat_item);
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void mod_zone_page_state(struct zone *, enum zone_stat_item, int);
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void inc_zone_page_state(struct page *, enum zone_stat_item);
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void dec_zone_page_state(struct page *, enum zone_stat_item);
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extern void inc_zone_state(struct zone *, enum zone_stat_item);
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extern void __inc_zone_state(struct zone *, enum zone_stat_item);
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extern void dec_zone_state(struct zone *, enum zone_stat_item);
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extern void __dec_zone_state(struct zone *, enum zone_stat_item);
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void refresh_cpu_vm_stats(int);
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#else /* CONFIG_SMP */
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/*
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* We do not maintain differentials in a single processor configuration.
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* The functions directly modify the zone and global counters.
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*/
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static inline void __mod_zone_page_state(struct zone *zone,
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enum zone_stat_item item, int delta)
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{
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zone_page_state_add(delta, zone, item);
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}
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static inline void __inc_zone_state(struct zone *zone, enum zone_stat_item item)
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{
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atomic_long_inc(&zone->vm_stat[item]);
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atomic_long_inc(&vm_stat[item]);
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}
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static inline void __inc_zone_page_state(struct page *page,
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enum zone_stat_item item)
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{
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__inc_zone_state(page_zone(page), item);
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}
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static inline void __dec_zone_state(struct zone *zone, enum zone_stat_item item)
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{
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atomic_long_dec(&zone->vm_stat[item]);
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atomic_long_dec(&vm_stat[item]);
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}
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static inline void __dec_zone_page_state(struct page *page,
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enum zone_stat_item item)
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{
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atomic_long_dec(&page_zone(page)->vm_stat[item]);
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atomic_long_dec(&vm_stat[item]);
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}
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/*
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* We only use atomic operations to update counters. So there is no need to
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* disable interrupts.
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*/
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#define inc_zone_page_state __inc_zone_page_state
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#define dec_zone_page_state __dec_zone_page_state
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#define mod_zone_page_state __mod_zone_page_state
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static inline void refresh_cpu_vm_stats(int cpu) { }
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#endif
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#endif /* _LINUX_VMSTAT_H */
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