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/spinlock_types.h>
8 #include <linux/wait.h>
9 #include <linux/cpumask.h>
11 struct percpu_ida_cpu;
15 * number of tags available to be allocated, as passed to
19 unsigned percpu_max_size;
20 unsigned percpu_batch_size;
22 struct percpu_ida_cpu __percpu *tag_cpu;
25 * Bitmap of cpus that (may) have tags on their percpu freelists:
26 * steal_tags() uses this to decide when to steal tags, and which cpus
27 * to try stealing from.
29 * It's ok for a freelist to be empty when its bit is set - steal_tags()
30 * will just keep looking - but the bitmap _must_ be set whenever a
31 * percpu freelist does have tags.
33 cpumask_t cpus_have_tags;
38 * When we go to steal tags from another cpu (see steal_tags()),
39 * we want to pick a cpu at random. Cycling through them every
40 * time we steal is a bit easier and more or less equivalent:
42 unsigned cpu_last_stolen;
44 /* For sleeping on allocation failure */
45 wait_queue_head_t wait;
48 * Global freelist - it's a stack where nr_free points to the
53 } ____cacheline_aligned_in_smp;
57 * Number of tags we move between the percpu freelist and the global freelist at
60 #define IDA_DEFAULT_PCPU_BATCH_MOVE 32U
61 /* Max size of percpu freelist, */
62 #define IDA_DEFAULT_PCPU_SIZE ((IDA_DEFAULT_PCPU_BATCH_MOVE * 3) / 2)
64 int percpu_ida_alloc(struct percpu_ida *pool, gfp_t gfp);
65 void percpu_ida_free(struct percpu_ida *pool, unsigned tag);
67 void percpu_ida_destroy(struct percpu_ida *pool);
68 int __percpu_ida_init(struct percpu_ida *pool, unsigned long nr_tags,
69 unsigned long max_size, unsigned long batch_size);
70 static inline int percpu_ida_init(struct percpu_ida *pool, unsigned long nr_tags)
72 return __percpu_ida_init(pool, nr_tags, IDA_DEFAULT_PCPU_SIZE,
73 IDA_DEFAULT_PCPU_BATCH_MOVE);
76 typedef int (*percpu_ida_cb)(unsigned, void *);
77 int percpu_ida_for_each_free(struct percpu_ida *pool, percpu_ida_cb fn,
80 unsigned percpu_ida_free_tags(struct percpu_ida *pool, int cpu);
81 #endif /* __PERCPU_IDA_H__ */