diff options
Diffstat (limited to 'include/linux/percpu_ida.h')
-rw-r--r-- | include/linux/percpu_ida.h | 60 |
1 files changed, 60 insertions, 0 deletions
diff --git a/include/linux/percpu_ida.h b/include/linux/percpu_ida.h new file mode 100644 index 000000000000..0b23edbee309 --- /dev/null +++ b/include/linux/percpu_ida.h @@ -0,0 +1,60 @@ +#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; + + 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; +}; + +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); + +#endif /* __PERCPU_IDA_H__ */ |