diff options
Diffstat (limited to 'include/os/linux/spl/sys')
| -rw-r--r-- | include/os/linux/spl/sys/shrinker.h | 122 |
1 files changed, 40 insertions, 82 deletions
diff --git a/include/os/linux/spl/sys/shrinker.h b/include/os/linux/spl/sys/shrinker.h index 4193bc5c4..e608cd30c 100644 --- a/include/os/linux/spl/sys/shrinker.h +++ b/include/os/linux/spl/sys/shrinker.h @@ -32,46 +32,37 @@ * Due to frequent changes in the shrinker API the following * compatibility wrappers should be used. They are as follows: * - * SPL_SHRINKER_DECLARE is used to declare the shrinker which is - * passed to spl_register_shrinker()/spl_unregister_shrinker(). Use - * shrinker_name to set the shrinker variable name, shrinker_callback - * to set the callback function, and seek_cost to define the cost of - * reclaiming an object. - * - * SPL_SHRINKER_DECLARE(shrinker_name, shrinker_callback, seek_cost); - * - * SPL_SHRINKER_CALLBACK_FWD_DECLARE is used when a forward declaration - * of the shrinker callback function is required. Only the callback - * function needs to be passed. - * - * SPL_SHRINKER_CALLBACK_FWD_DECLARE(shrinker_callback); - * - * SPL_SHRINKER_CALLBACK_WRAPPER is used to declare the callback function - * which is registered with the shrinker. This function will call your - * custom shrinker which must use the following prototype. Notice the - * leading __'s, these must be appended to the callback_function name. - * - * int __shrinker_callback(struct shrinker *, struct shrink_control *) - * SPL_SHRINKER_CALLBACK_WRAPPER(shrinker_callback);a + * SPL_SHRINKER_DECLARE(varname, countfunc, scanfunc, seek_cost); * + * SPL_SHRINKER_DECLARE is used to declare a shrinker with the name varname, + * which is passed to spl_register_shrinker()/spl_unregister_shrinker(). + * The countfunc returns the number of free-able objects. + * The scanfunc returns the number of objects that were freed. + * The callbacks can return SHRINK_STOP if further calls can't make any more + * progress. Note that a return value of SHRINK_EMPTY is currently not + * supported. * * Example: * - * SPL_SHRINKER_CALLBACK_FWD_DECLARE(my_shrinker_fn); - * SPL_SHRINKER_DECLARE(my_shrinker, my_shrinker_fn, 1); - * - * static int - * __my_shrinker_fn(struct shrinker *shrink, struct shrink_control *sc) + * static unsigned long + * my_count(struct shrinker *shrink, struct shrink_control *sc) * { - * if (sc->nr_to_scan) { - * ...scan objects in the cache and reclaim them... - * } - * * ...calculate number of objects in the cache... * * return (number of objects in the cache); * } - * SPL_SHRINKER_CALLBACK_WRAPPER(my_shrinker_fn); + * + * static unsigned long + * my_scan(struct shrinker *shrink, struct shrink_control *sc) + * { + * ...scan objects in the cache and reclaim them... + * } + * + * SPL_SHRINKER_DECLARE(my_shrinker, my_count, my_scan, DEFAULT_SEEKS); + * + * void my_init_func(void) { + * spl_register_shrinker(&my_shrinker); + * } */ #define spl_register_shrinker(x) register_shrinker(x) @@ -81,60 +72,34 @@ * Linux 3.0 to 3.11 Shrinker API Compatibility. */ #if defined(HAVE_SINGLE_SHRINKER_CALLBACK) -#define SPL_SHRINKER_DECLARE(s, x, y) \ -static struct shrinker s = { \ - .shrink = x, \ - .seeks = y \ -} - -#define SPL_SHRINKER_CALLBACK_FWD_DECLARE(fn) \ -static int fn(struct shrinker *, struct shrink_control *) - -#define SPL_SHRINKER_CALLBACK_WRAPPER(fn) \ +#define SPL_SHRINKER_DECLARE(varname, countfunc, scanfunc, seek_cost) \ static int \ -fn(struct shrinker *shrink, struct shrink_control *sc) \ +__ ## varname ## _wrapper(struct shrinker *shrink, struct shrink_control *sc)\ { \ - return (__ ## fn(shrink, sc)); \ + if (sc->nr_to_scan != 0) { \ + (void) scanfunc(shrink, sc); \ + } \ + return (countfunc(shrink, sc)); \ +} \ + \ +static struct shrinker varname = { \ + .shrink = __ ## varname ## _wrapper, \ + .seeks = seek_cost \ } +#define SHRINK_STOP (-1) + /* * Linux 3.12 and later Shrinker API Compatibility. */ #elif defined(HAVE_SPLIT_SHRINKER_CALLBACK) -#define SPL_SHRINKER_DECLARE(s, x, y) \ -static struct shrinker s = { \ - .count_objects = x ## _count_objects, \ - .scan_objects = x ## _scan_objects, \ - .seeks = y \ +#define SPL_SHRINKER_DECLARE(varname, countfunc, scanfunc, seek_cost) \ +static struct shrinker varname = { \ + .count_objects = countfunc, \ + .scan_objects = scanfunc, \ + .seeks = seek_cost \ } -#define SPL_SHRINKER_CALLBACK_FWD_DECLARE(fn) \ -static unsigned long fn ## _count_objects(struct shrinker *, \ - struct shrink_control *); \ -static unsigned long fn ## _scan_objects(struct shrinker *, \ - struct shrink_control *) - -#define SPL_SHRINKER_CALLBACK_WRAPPER(fn) \ -static unsigned long \ -fn ## _count_objects(struct shrinker *shrink, struct shrink_control *sc)\ -{ \ - int __ret__; \ - \ - sc->nr_to_scan = 0; \ - __ret__ = __ ## fn(NULL, sc); \ - \ - /* Errors may not be returned and must be converted to zeros */ \ - return ((__ret__ < 0) ? 0 : __ret__); \ -} \ - \ -static unsigned long \ -fn ## _scan_objects(struct shrinker *shrink, struct shrink_control *sc) \ -{ \ - int __ret__; \ - \ - __ret__ = __ ## fn(NULL, sc); \ - return ((__ret__ < 0) ? SHRINK_STOP : __ret__); \ -} #else /* * Linux 2.x to 2.6.22, or a newer shrinker API has been introduced. @@ -142,11 +107,4 @@ fn ## _scan_objects(struct shrinker *shrink, struct shrink_control *sc) \ #error "Unknown shrinker callback" #endif -#if defined(HAVE_SPLIT_SHRINKER_CALLBACK) -typedef unsigned long spl_shrinker_t; -#else -typedef int spl_shrinker_t; -#define SHRINK_STOP (-1) -#endif - #endif /* SPL_SHRINKER_H */ |