[linux-2.6-block.git] / include / linux / percpu_ida.h

#ifndef __PERCPU_IDA_H__
#define __PERCPU_IDA_H__

#include <linux/types.h>
#include <linux/bitops.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/spinlock_types.h>
#include <linux/wait.h>
#include <linux/cpumask.h>

struct percpu_ida_cpu;

struct percpu_ida {
	/*
	 * number of tags available to be allocated, as passed to
	 * percpu_ida_init()
	 */
	unsigned			nr_tags;
	unsigned			percpu_max_size;
	unsigned			percpu_batch_size;

	struct percpu_ida_cpu __percpu	*tag_cpu;

	/*
	 * Bitmap of cpus that (may) have tags on their percpu freelists:
	 * steal_tags() uses this to decide when to steal tags, and which cpus
	 * to try stealing from.
	 *
	 * It's ok for a freelist to be empty when its bit is set - steal_tags()
	 * will just keep looking - but the bitmap _must_ be set whenever a
	 * percpu freelist does have tags.
	 */
	cpumask_t			cpus_have_tags;

	struct {
		spinlock_t		lock;
		/*
		 * When we go to steal tags from another cpu (see steal_tags()),
		 * we want to pick a cpu at random. Cycling through them every
		 * time we steal is a bit easier and more or less equivalent:
		 */
		unsigned		cpu_last_stolen;

		/* For sleeping on allocation failure */
		wait_queue_head_t	wait;

		/*
		 * Global freelist - it's a stack where nr_free points to the
		 * top
		 */
		unsigned		nr_free;
		unsigned		*freelist;
	} ____cacheline_aligned_in_smp;
};

/*
 * Number of tags we move between the percpu freelist and the global freelist at
 * a time
 */
#define IDA_DEFAULT_PCPU_BATCH_MOVE	32U
/* Max size of percpu freelist, */
#define IDA_DEFAULT_PCPU_SIZE	((IDA_DEFAULT_PCPU_BATCH_MOVE * 3) / 2)

int percpu_ida_alloc(struct percpu_ida *pool, int state);
void percpu_ida_free(struct percpu_ida *pool, unsigned tag);

void percpu_ida_destroy(struct percpu_ida *pool);
int __percpu_ida_init(struct percpu_ida *pool, unsigned long nr_tags,
	unsigned long max_size, unsigned long batch_size);
static inline int percpu_ida_init(struct percpu_ida *pool, unsigned long nr_tags)
{
	return __percpu_ida_init(pool, nr_tags, IDA_DEFAULT_PCPU_SIZE,
		IDA_DEFAULT_PCPU_BATCH_MOVE);
}

typedef int (*percpu_ida_cb)(unsigned, void *);
int percpu_ida_for_each_free(struct percpu_ida *pool, percpu_ida_cb fn,
	void *data);

unsigned percpu_ida_free_tags(struct percpu_ida *pool, int cpu);
#endif /* __PERCPU_IDA_H__ */
Commit	Line	Data
798ab48e KO	1	#ifndef __PERCPU_IDA_H__
	2	#define __PERCPU_IDA_H__
	3
	4	#include <linux/types.h>
	5	#include <linux/bitops.h>
	6	#include <linux/init.h>
6f6b5d1e	7	#include <linux/sched.h>
798ab48e KO	8	#include <linux/spinlock_types.h>
	9	#include <linux/wait.h>
	10	#include <linux/cpumask.h>
	11
	12	struct percpu_ida_cpu;
	13
	14	struct percpu_ida {
	15	/*
	16	* number of tags available to be allocated, as passed to
	17	* percpu_ida_init()
	18	*/
	19	unsigned nr_tags;
e26b53d0 SL	20	unsigned percpu_max_size;
e26b53d0 SL	21	unsigned percpu_batch_size;
798ab48e KO	22
	23	struct percpu_ida_cpu __percpu *tag_cpu;
	24
	25	/*
	26	* Bitmap of cpus that (may) have tags on their percpu freelists:
	27	* steal_tags() uses this to decide when to steal tags, and which cpus
	28	* to try stealing from.
	29	*
	30	* It's ok for a freelist to be empty when its bit is set - steal_tags()
	31	* will just keep looking - but the bitmap _must_ be set whenever a
	32	* percpu freelist does have tags.
	33	*/
	34	cpumask_t cpus_have_tags;
	35
	36	struct {
	37	spinlock_t lock;
	38	/*
	39	* When we go to steal tags from another cpu (see steal_tags()),
	40	* we want to pick a cpu at random. Cycling through them every
	41	* time we steal is a bit easier and more or less equivalent:
	42	*/
	43	unsigned cpu_last_stolen;
	44
	45	/* For sleeping on allocation failure */
	46	wait_queue_head_t wait;
	47
	48	/*
	49	* Global freelist - it's a stack where nr_free points to the
	50	* top
	51	*/
	52	unsigned nr_free;
	53	unsigned *freelist;
	54	} ____cacheline_aligned_in_smp;
	55	};
	56
e26b53d0 SL	57	/*
	58	* Number of tags we move between the percpu freelist and the global freelist at
	59	* a time
	60	*/
	61	#define IDA_DEFAULT_PCPU_BATCH_MOVE 32U
	62	/* Max size of percpu freelist, */
	63	#define IDA_DEFAULT_PCPU_SIZE ((IDA_DEFAULT_PCPU_BATCH_MOVE * 3) / 2)
	64
6f6b5d1e	65	int percpu_ida_alloc(struct percpu_ida *pool, int state);
798ab48e KO	66	void percpu_ida_free(struct percpu_ida *pool, unsigned tag);
	67
	68	void percpu_ida_destroy(struct percpu_ida *pool);
e26b53d0 SL	69	int __percpu_ida_init(struct percpu_ida *pool, unsigned long nr_tags,
	70	unsigned long max_size, unsigned long batch_size);
	71	static inline int percpu_ida_init(struct percpu_ida *pool, unsigned long nr_tags)
	72	{
	73	return __percpu_ida_init(pool, nr_tags, IDA_DEFAULT_PCPU_SIZE,
	74	IDA_DEFAULT_PCPU_BATCH_MOVE);
	75	}
798ab48e	76
7fc2ba17 SL	77	typedef int (percpu_ida_cb)(unsigned, void );
	78	int percpu_ida_for_each_free(struct percpu_ida *pool, percpu_ida_cb fn,
	79	void *data);
	80
1dddc01a	81	unsigned percpu_ida_free_tags(struct percpu_ida *pool, int cpu);
798ab48e	82	#endif /* __PERCPU_IDA_H__ */