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> 7#include <linux/sched.h> 8#include <linux/spinlock_types.h> 9#include <linux/wait.h> 10#include <linux/cpumask.h> 11 12struct percpu_ida_cpu; 13 14struct percpu_ida { 15 /* 16 * number of tags available to be allocated, as passed to 17 * percpu_ida_init() 18 */ 19 unsigned nr_tags; 20 unsigned percpu_max_size; 21 unsigned percpu_batch_size; 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 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 65int percpu_ida_alloc(struct percpu_ida *pool, int state); 66void percpu_ida_free(struct percpu_ida *pool, unsigned tag); 67 68void percpu_ida_destroy(struct percpu_ida *pool); 69int __percpu_ida_init(struct percpu_ida *pool, unsigned long nr_tags, 70 unsigned long max_size, unsigned long batch_size); 71static 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} 76 77typedef int (*percpu_ida_cb)(unsigned, void *); 78int percpu_ida_for_each_free(struct percpu_ida *pool, percpu_ida_cb fn, 79 void *data); 80 81unsigned percpu_ida_free_tags(struct percpu_ida *pool, int cpu); 82#endif /* __PERCPU_IDA_H__ */ 83