1 #ifndef __PERCPU_IDA_H__
2 #define __PERCPU_IDA_H__
4 #include <linux/types.h>
5 #include <linux/bitops.h>
6 #include <linux/init.h>
7 #include <linux/sched.h>
8 #include <linux/spinlock_types.h>
9 #include <linux/wait.h>
10 #include <linux/cpumask.h>
12 struct percpu_ida_cpu;
16 * number of tags available to be allocated, as passed to
20 unsigned percpu_max_size;
21 unsigned percpu_batch_size;
23 struct percpu_ida_cpu __percpu *tag_cpu;
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.
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.
34 cpumask_t cpus_have_tags;
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:
43 unsigned cpu_last_stolen;
45 /* For sleeping on allocation failure */
46 wait_queue_head_t wait;
49 * Global freelist - it's a stack where nr_free points to the
54 } ____cacheline_aligned_in_smp;
58 * Number of tags we move between the percpu freelist and the global freelist at
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)
65 int percpu_ida_alloc(struct percpu_ida *pool, int state);
66 void percpu_ida_free(struct percpu_ida *pool, unsigned tag);
68 void percpu_ida_destroy(struct percpu_ida *pool);
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)
73 return __percpu_ida_init(pool, nr_tags, IDA_DEFAULT_PCPU_SIZE,
74 IDA_DEFAULT_PCPU_BATCH_MOVE);
77 typedef int (*percpu_ida_cb)(unsigned, void *);
78 int percpu_ida_for_each_free(struct percpu_ida *pool, percpu_ida_cb fn,
81 unsigned percpu_ida_free_tags(struct percpu_ida *pool, int cpu);
82 #endif /* __PERCPU_IDA_H__ */