[mirror_ubuntu-hirsute-kernel.git] / include / linux / percpu_counter.h

#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 *counters;
};

#if NR_CPUS >= 16
#define FBC_BATCH	(NR_CPUS*2)
#else
#define FBC_BATCH	(NR_CPUS*4)
#endif

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, FBC_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;
}

#define __percpu_counter_add(fbc, amount, batch) \
	percpu_counter_add(fbc, amount)

static inline void
percpu_counter_add(struct percpu_counter *fbc, s64 amount)
{
	preempt_disable();
	fbc->count += amount;
	preempt_enable();
}

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 */
Commit	Line	Data
1da177e4 LT	1	#ifndef _LINUX_PERCPU_COUNTER_H
	2	#define _LINUX_PERCPU_COUNTER_H
	3	/*
	4	* A simple "approximate counter" for use in ext2 and ext3 superblocks.
	5	*
	6	* WARNING: these things are HUGE. 4 kbytes per counter on 32-way P4.
	7	*/
	8
1da177e4 LT	9	#include <linux/spinlock.h>
1da177e4 LT	10	#include <linux/smp.h>
c67ad917	11	#include <linux/list.h>
1da177e4 LT	12	#include <linux/threads.h>
1da177e4 LT	13	#include <linux/percpu.h>
0216bfcf	14	#include <linux/types.h>
1da177e4 LT	15
	16	#ifdef CONFIG_SMP
	17
	18	struct percpu_counter {
	19	spinlock_t lock;
0216bfcf	20	s64 count;
c67ad917 AM	21	#ifdef CONFIG_HOTPLUG_CPU
	22	struct list_head list; /* All percpu_counters are on a list */
	23	#endif
0216bfcf	24	s32 *counters;
1da177e4 LT	25	};
	26
	27	#if NR_CPUS >= 16
	28	#define FBC_BATCH (NR_CPUS*2)
	29	#else
	30	#define FBC_BATCH (NR_CPUS*4)
	31	#endif
	32
ea319518 PZ	33	int __percpu_counter_init(struct percpu_counter *fbc, s64 amount,
	34	struct lock_class_key *key);
	35
	36	#define percpu_counter_init(fbc, value) \
	37	({ \
	38	static struct lock_class_key __key; \
	39	\
	40	__percpu_counter_init(fbc, value, &__key); \
	41	})
	42
c67ad917	43	void percpu_counter_destroy(struct percpu_counter *fbc);
3a587f47	44	void percpu_counter_set(struct percpu_counter *fbc, s64 amount);
20e89767	45	void __percpu_counter_add(struct percpu_counter *fbc, s64 amount, s32 batch);
1f7c14c6	46	s64 __percpu_counter_sum(struct percpu_counter *fbc);
1da177e4	47
20e89767	48	static inline void percpu_counter_add(struct percpu_counter *fbc, s64 amount)
252e0ba6 PZ	49	{
	50	__percpu_counter_add(fbc, amount, FBC_BATCH);
	51	}
	52
bf1d89c8 PZ	53	static inline s64 percpu_counter_sum_positive(struct percpu_counter *fbc)
bf1d89c8 PZ	54	{
1f7c14c6	55	s64 ret = __percpu_counter_sum(fbc);
bf1d89c8 PZ	56	return ret < 0 ? 0 : ret;
	57	}
	58
	59	static inline s64 percpu_counter_sum(struct percpu_counter *fbc)
	60	{
1f7c14c6	61	return __percpu_counter_sum(fbc);
bf1d89c8 PZ	62	}
bf1d89c8 PZ	63
0216bfcf	64	static inline s64 percpu_counter_read(struct percpu_counter *fbc)
1da177e4 LT	65	{
	66	return fbc->count;
	67	}
	68
	69	/*
	70	* It is possible for the percpu_counter_read() to return a small negative
	71	* number for some counter which should never be negative.
0216bfcf	72	*
1da177e4	73	*/
0216bfcf	74	static inline s64 percpu_counter_read_positive(struct percpu_counter *fbc)
1da177e4	75	{
0216bfcf	76	s64 ret = fbc->count;
1da177e4 LT	77
1da177e4 LT	78	barrier(); /* Prevent reloads of fbc->count */
0216bfcf	79	if (ret >= 0)
1da177e4 LT	80	return ret;
	81	return 1;
	82	}
	83
	84	#else
	85
	86	struct percpu_counter {
0216bfcf	87	s64 count;
1da177e4 LT	88	};
1da177e4 LT	89
833f4077	90	static inline int percpu_counter_init(struct percpu_counter *fbc, s64 amount)
1da177e4	91	{
0216bfcf	92	fbc->count = amount;
833f4077	93	return 0;
1da177e4 LT	94	}
	95
	96	static inline void percpu_counter_destroy(struct percpu_counter *fbc)
	97	{
	98	}
	99
3a587f47 PZ	100	static inline void percpu_counter_set(struct percpu_counter *fbc, s64 amount)
	101	{
	102	fbc->count = amount;
	103	}
	104
252e0ba6 PZ	105	#define __percpu_counter_add(fbc, amount, batch) \
	106	percpu_counter_add(fbc, amount)
	107
1da177e4	108	static inline void
20e89767	109	percpu_counter_add(struct percpu_counter *fbc, s64 amount)
1da177e4 LT	110	{
	111	preempt_disable();
	112	fbc->count += amount;
	113	preempt_enable();
	114	}
	115
0216bfcf	116	static inline s64 percpu_counter_read(struct percpu_counter *fbc)
1da177e4 LT	117	{
	118	return fbc->count;
	119	}
	120
0216bfcf	121	static inline s64 percpu_counter_read_positive(struct percpu_counter *fbc)
1da177e4 LT	122	{
	123	return fbc->count;
	124	}
	125
52d9f3b4	126	static inline s64 percpu_counter_sum_positive(struct percpu_counter *fbc)
e2bab3d9 AM	127	{
	128	return percpu_counter_read_positive(fbc);
	129	}
	130
bf1d89c8 PZ	131	static inline s64 percpu_counter_sum(struct percpu_counter *fbc)
	132	{
	133	return percpu_counter_read(fbc);
	134	}
	135
1da177e4 LT	136	#endif /* CONFIG_SMP */
	137
	138	static inline void percpu_counter_inc(struct percpu_counter *fbc)
	139	{
aa0dff2d	140	percpu_counter_add(fbc, 1);
1da177e4 LT	141	}
	142
	143	static inline void percpu_counter_dec(struct percpu_counter *fbc)
	144	{
aa0dff2d	145	percpu_counter_add(fbc, -1);
1da177e4 LT	146	}
1da177e4 LT	147
3cb4f9fa PZ	148	static inline void percpu_counter_sub(struct percpu_counter *fbc, s64 amount)
	149	{
	150	percpu_counter_add(fbc, -amount);
	151	}
	152
1da177e4	153	#endif /* _LINUX_PERCPU_COUNTER_H */