linux-stable/include/linux/percpu_counter.h
Linus Torvalds 0a135ba14d Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu:
  percpu: add __percpu sparse annotations to what's left
  percpu: add __percpu sparse annotations to fs
  percpu: add __percpu sparse annotations to core kernel subsystems
  local_t: Remove leftover local.h
  this_cpu: Remove pageset_notifier
  this_cpu: Page allocator conversion
  percpu, x86: Generic inc / dec percpu instructions
  local_t: Move local.h include to ringbuffer.c and ring_buffer_benchmark.c
  module: Use this_cpu_xx to dynamically allocate counters
  local_t: Remove cpu_local_xx macros
  percpu: refactor the code in pcpu_[de]populate_chunk()
  percpu: remove compile warnings caused by __verify_pcpu_ptr()
  percpu: make accessors check for percpu pointer in sparse
  percpu: add __percpu for sparse.
  percpu: make access macros universal
  percpu: remove per_cpu__ prefix.
2010-03-03 07:34:18 -08:00

152 lines
3.3 KiB
C

#ifndef _LINUX_PERCPU_COUNTER_H
#define _LINUX_PERCPU_COUNTER_H
/*
* A simple "approximate counter" for use in ext2 and ext3 superblocks.
*
* WARNING: these things are HUGE. 4 kbytes per counter on 32-way P4.
*/
#include <linux/spinlock.h>
#include <linux/smp.h>
#include <linux/list.h>
#include <linux/threads.h>
#include <linux/percpu.h>
#include <linux/types.h>
#ifdef CONFIG_SMP
struct percpu_counter {
spinlock_t lock;
s64 count;
#ifdef CONFIG_HOTPLUG_CPU
struct list_head list; /* All percpu_counters are on a list */
#endif
s32 __percpu *counters;
};
extern int percpu_counter_batch;
int __percpu_counter_init(struct percpu_counter *fbc, s64 amount,
struct lock_class_key *key);
#define percpu_counter_init(fbc, value) \
({ \
static struct lock_class_key __key; \
\
__percpu_counter_init(fbc, value, &__key); \
})
void percpu_counter_destroy(struct percpu_counter *fbc);
void percpu_counter_set(struct percpu_counter *fbc, s64 amount);
void __percpu_counter_add(struct percpu_counter *fbc, s64 amount, s32 batch);
s64 __percpu_counter_sum(struct percpu_counter *fbc);
static inline void percpu_counter_add(struct percpu_counter *fbc, s64 amount)
{
__percpu_counter_add(fbc, amount, percpu_counter_batch);
}
static inline s64 percpu_counter_sum_positive(struct percpu_counter *fbc)
{
s64 ret = __percpu_counter_sum(fbc);
return ret < 0 ? 0 : ret;
}
static inline s64 percpu_counter_sum(struct percpu_counter *fbc)
{
return __percpu_counter_sum(fbc);
}
static inline s64 percpu_counter_read(struct percpu_counter *fbc)
{
return fbc->count;
}
/*
* It is possible for the percpu_counter_read() to return a small negative
* number for some counter which should never be negative.
*
*/
static inline s64 percpu_counter_read_positive(struct percpu_counter *fbc)
{
s64 ret = fbc->count;
barrier(); /* Prevent reloads of fbc->count */
if (ret >= 0)
return ret;
return 1;
}
#else
struct percpu_counter {
s64 count;
};
static inline int percpu_counter_init(struct percpu_counter *fbc, s64 amount)
{
fbc->count = amount;
return 0;
}
static inline void percpu_counter_destroy(struct percpu_counter *fbc)
{
}
static inline void percpu_counter_set(struct percpu_counter *fbc, s64 amount)
{
fbc->count = amount;
}
static inline void
percpu_counter_add(struct percpu_counter *fbc, s64 amount)
{
preempt_disable();
fbc->count += amount;
preempt_enable();
}
static inline void
__percpu_counter_add(struct percpu_counter *fbc, s64 amount, s32 batch)
{
percpu_counter_add(fbc, amount);
}
static inline s64 percpu_counter_read(struct percpu_counter *fbc)
{
return fbc->count;
}
static inline s64 percpu_counter_read_positive(struct percpu_counter *fbc)
{
return fbc->count;
}
static inline s64 percpu_counter_sum_positive(struct percpu_counter *fbc)
{
return percpu_counter_read_positive(fbc);
}
static inline s64 percpu_counter_sum(struct percpu_counter *fbc)
{
return percpu_counter_read(fbc);
}
#endif /* CONFIG_SMP */
static inline void percpu_counter_inc(struct percpu_counter *fbc)
{
percpu_counter_add(fbc, 1);
}
static inline void percpu_counter_dec(struct percpu_counter *fbc)
{
percpu_counter_add(fbc, -1);
}
static inline void percpu_counter_sub(struct percpu_counter *fbc, s64 amount)
{
percpu_counter_add(fbc, -amount);
}
#endif /* _LINUX_PERCPU_COUNTER_H */