forked from luck/tmp_suning_uos_patched
8e125cd855
09f363c7("vmscan: fix shrinker callback bug in fs/super.c") fixed a shrinker callback which was returning -1 when nr_to_scan is zero, which caused excessive slab scanning. But635697c6("vmscan: fix initial shrinker size handling") fixed the problem, again so we can freely return -1 although nr_to_scan is zero. So let's revert09f363c7because the comment added in09f363c7made an unnecessary rule. Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Mikulas Patocka <mpatocka@redhat.com> Cc: Konstantin Khlebnikov <khlebnikov@openvz.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
43 lines
1.4 KiB
C
43 lines
1.4 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 '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
|