diff options
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/shrinker.h | 38 |
1 files changed, 9 insertions, 29 deletions
diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h index 884e76222..ac6b8ee07 100644 --- a/include/linux/shrinker.h +++ b/include/linux/shrinker.h @@ -4,12 +4,6 @@ /* * This struct is used to pass information from page reclaim to the shrinkers. * We consolidate the values for easier extention later. - * - * The 'gfpmask' refers to the allocation we are currently trying to - * fulfil. - * - * Note that 'shrink' will be passed nr_to_scan == 0 when the VM is - * querying the cache size, so a fastpath for that case is appropriate. */ struct shrink_control { gfp_t gfp_mask; @@ -18,37 +12,23 @@ struct shrink_control { unsigned long nr_to_scan; }; -#define SHRINK_STOP (~0UL) /* * A callback you can register to apply pressure to ageable caches. * - * @shrink() should look through the least-recently-used 'nr_to_scan' entries - * and attempt to free them up. It should return the number of objects which - * remain in the cache. If it returns -1, it means it cannot do any scanning at - * this time (eg. there is a risk of deadlock). + * 'sc' is passed shrink_control which includes a count 'nr_to_scan' + * and a 'gfpmask'. It should look through the least-recently-used + * 'nr_to_scan' entries and attempt to free them up. It should return + * the number of objects which remain in the cache. If it returns -1, it means + * it cannot do any scanning at this time (eg. there is a risk of deadlock). * - * @count_objects should return the number of freeable items in the cache. If - * there are no objects to free or the number of freeable items cannot be - * determined, it should return 0. No deadlock checks should be done during the - * count callback - the shrinker relies on aggregating scan counts that couldn't - * be executed due to potential deadlocks to be run at a later call when the - * deadlock condition is no longer pending. + * The 'gfpmask' refers to the allocation we are currently trying to + * fulfil. * - * @scan_objects will only be called if @count_objects returned a non-zero - * value for the number of freeable objects. The callout should scan the cache - * and attempt to free items from the cache. It should then return the number - * of objects freed during the scan, or SHRINK_STOP if progress cannot be made - * due to potential deadlocks. If SHRINK_STOP is returned, then no further - * attempts to call the @scan_objects will be made from the current reclaim - * context. + * Note that 'shrink' will be passed nr_to_scan == 0 when the VM is + * querying the cache size, so a fastpath for that case is appropriate. */ struct shrinker { int (*shrink)(struct shrinker *, struct shrink_control *sc); - unsigned long (*count_objects)(struct shrinker *, - struct shrink_control *sc); - unsigned long (*scan_objects)(struct shrinker *, - struct shrink_control *sc); - int seeks; /* seeks to recreate an obj */ long batch; /* reclaim batch size, 0 = default */ |