1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889909192939495969798 |
- /* SPDX-License-Identifier: GPL-2.0 */
- #ifndef _LINUX_SHRINKER_H
- #define _LINUX_SHRINKER_H
- #include <linux/android_vendor.h>
- /*
- * 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.
- */
- struct shrink_control {
- gfp_t gfp_mask;
- /* current node being shrunk (for NUMA aware shrinkers) */
- int nid;
- /*
- * How many objects scan_objects should scan and try to reclaim.
- * This is reset before every call, so it is safe for callees
- * to modify.
- */
- unsigned long nr_to_scan;
- /*
- * How many objects did scan_objects process?
- * This defaults to nr_to_scan before every call, but the callee
- * should track its actual progress.
- */
- unsigned long nr_scanned;
- /* current memcg being shrunk (for memcg aware shrinkers) */
- struct mem_cgroup *memcg;
- ANDROID_OEM_DATA_ARRAY(1, 3);
- };
- #define SHRINK_STOP (~0UL)
- #define SHRINK_EMPTY (~0UL - 1)
- /*
- * A callback you can register to apply pressure to ageable caches.
- *
- * @count_objects should return the number of freeable items in the cache. If
- * there are no objects to free, it should return SHRINK_EMPTY, while 0 is
- * returned in cases of the number of freeable items cannot be determined
- * or shrinker should skip this cache for this time (e.g., their number
- * is below shrinkable limit). 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.
- *
- * @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.
- *
- * @flags determine the shrinker abilities, like numa awareness
- */
- struct shrinker {
- unsigned long (*count_objects)(struct shrinker *,
- struct shrink_control *sc);
- unsigned long (*scan_objects)(struct shrinker *,
- struct shrink_control *sc);
- long batch; /* reclaim batch size, 0 = default */
- int seeks; /* seeks to recreate an obj */
- unsigned flags;
- /* These are for internal use */
- struct list_head list;
- #ifdef CONFIG_MEMCG
- /* ID in shrinker_idr */
- int id;
- #endif
- /* objs pending delete, per node */
- atomic_long_t *nr_deferred;
- };
- #define DEFAULT_SEEKS 2 /* A good number if you don't know better. */
- /* Flags */
- #define SHRINKER_NUMA_AWARE (1 << 0)
- #define SHRINKER_MEMCG_AWARE (1 << 1)
- /*
- * It just makes sense when the shrinker is also MEMCG_AWARE for now,
- * non-MEMCG_AWARE shrinker should not have this flag set.
- */
- #define SHRINKER_NONSLAB (1 << 2)
- extern int prealloc_shrinker(struct shrinker *shrinker);
- extern void register_shrinker_prepared(struct shrinker *shrinker);
- extern int register_shrinker(struct shrinker *shrinker);
- extern void unregister_shrinker(struct shrinker *shrinker);
- extern void free_prealloced_shrinker(struct shrinker *shrinker);
- #endif
|