mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 19:00:25 +00:00
![Konstantin Khlebnikov](/assets/img/avatar_default.png)
Use atomic-long operations instead of looping around cmpxchg(). [akpm@linux-foundation.org: massage atomic.h inclusions] Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Dave Chinner <david@fromorbit.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
43 lines
1.5 KiB
C
43 lines
1.5 KiB
C
#ifndef _LINUX_SHRINKER_H
|
|
#define _LINUX_SHRINKER_H
|
|
|
|
/*
|
|
* This struct is used to pass information from page reclaim to the shrinkers.
|
|
* We consolidate the values for easier extention later.
|
|
*/
|
|
struct shrink_control {
|
|
gfp_t gfp_mask;
|
|
|
|
/* How many slab objects shrinker() should scan and try to reclaim */
|
|
unsigned long nr_to_scan;
|
|
};
|
|
|
|
/*
|
|
* A callback you can register to apply pressure to ageable caches.
|
|
*
|
|
* '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).
|
|
* The callback must not return -1 if nr_to_scan is zero.
|
|
*
|
|
* 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 shrinker {
|
|
int (*shrink)(struct shrinker *, struct shrink_control *sc);
|
|
int seeks; /* seeks to recreate an obj */
|
|
long batch; /* reclaim batch size, 0 = default */
|
|
|
|
/* These are for internal use */
|
|
struct list_head list;
|
|
atomic_long_t nr_in_batch; /* objs pending delete */
|
|
};
|
|
#define DEFAULT_SEEKS 2 /* A good number if you don't know better. */
|
|
extern void register_shrinker(struct shrinker *);
|
|
extern void unregister_shrinker(struct shrinker *);
|
|
#endif
|