linux-stable/include/linux/shrinker.h
T.J. Mercier b7217a0bbe mm: shrinkers: add missing includes for undeclared types
The shrinker.h header depends on a user including other headers before it
for types used by shrinker.h.  Fix this by including the appropriate
headers in shrinker.h.

./include/linux/shrinker.h:13:9: error: unknown type name `gfp_t'
   13 |         gfp_t gfp_mask;
      |         ^~~~~
./include/linux/shrinker.h:71:26: error: field `list' has incomplete type
   71 |         struct list_head list;
      |                          ^~~~
./include/linux/shrinker.h:82:9: error: unknown type name `atomic_long_t'
   82 |         atomic_long_t *nr_deferred;
      |

Link: https://lkml.kernel.org/r/20221114235949.201749-1-tjmercier@google.com
Fixes: 83aeeada7c ("vmscan: use atomic-long for shrinker batching")
Fixes: b0d40c92ad ("superblock: introduce per-sb cache shrinker infrastructure")
Signed-off-by: T.J. Mercier <tjmercier@google.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-30 15:58:55 -08:00

127 lines
4.1 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_SHRINKER_H
#define _LINUX_SHRINKER_H
#include <linux/atomic.h>
#include <linux/types.h>
/*
* This struct is used to pass information from page reclaim to the shrinkers.
* We consolidate the values for easier extension 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;
};
#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
#ifdef CONFIG_SHRINKER_DEBUG
int debugfs_id;
const char *name;
struct dentry *debugfs_entry;
#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_REGISTERED (1 << 0)
#define SHRINKER_NUMA_AWARE (1 << 1)
#define SHRINKER_MEMCG_AWARE (1 << 2)
/*
* 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 << 3)
extern int __printf(2, 3) prealloc_shrinker(struct shrinker *shrinker,
const char *fmt, ...);
extern void register_shrinker_prepared(struct shrinker *shrinker);
extern int __printf(2, 3) register_shrinker(struct shrinker *shrinker,
const char *fmt, ...);
extern void unregister_shrinker(struct shrinker *shrinker);
extern void free_prealloced_shrinker(struct shrinker *shrinker);
extern void synchronize_shrinkers(void);
#ifdef CONFIG_SHRINKER_DEBUG
extern int shrinker_debugfs_add(struct shrinker *shrinker);
extern void shrinker_debugfs_remove(struct shrinker *shrinker);
extern int __printf(2, 3) shrinker_debugfs_rename(struct shrinker *shrinker,
const char *fmt, ...);
#else /* CONFIG_SHRINKER_DEBUG */
static inline int shrinker_debugfs_add(struct shrinker *shrinker)
{
return 0;
}
static inline void shrinker_debugfs_remove(struct shrinker *shrinker)
{
}
static inline __printf(2, 3)
int shrinker_debugfs_rename(struct shrinker *shrinker, const char *fmt, ...)
{
return 0;
}
#endif /* CONFIG_SHRINKER_DEBUG */
#endif /* _LINUX_SHRINKER_H */