#ifndef __PERCPU_IDA_H__ #define __PERCPU_IDA_H__ #include <linux/types.h> #include <linux/bitops.h> #include <linux/init.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, gfp_t gfp); 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__ */