fs/xfs/xfs_mru_cache.h

   1 /*
   2  * Copyright (c) 2006-2007 Silicon Graphics, Inc.
   3  * All Rights Reserved.
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it would be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write the Free Software Foundation,
  16  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17  */
  18 #ifndef __XFS_MRU_CACHE_H__
  19 #define __XFS_MRU_CACHE_H__
  20
  21
  22 /* Function pointer type for callback to free a client's data pointer. */
  23 typedef void (*xfs_mru_cache_free_func_t)(unsigned long, void*);
  24
  25 typedef struct xfs_mru_cache
  26 {
  27         struct radix_tree_root  store;     /* Core storage data structure.  */
  28         struct list_head        *lists;    /* Array of lists, one per grp.  */
  29         struct list_head        reap_list; /* Elements overdue for reaping. */
  30         spinlock_t              lock;      /* Lock to protect this struct.  */
  31         unsigned int            grp_count; /* Number of discrete groups.    */
  32         unsigned int            grp_time;  /* Time period spanned by grps.  */
  33         unsigned int            lru_grp;   /* Group containing time zero.   */
  34         unsigned long           time_zero; /* Time first element was added. */
  35         xfs_mru_cache_free_func_t free_func; /* Function pointer for freeing. */
  36         struct delayed_work     work;      /* Workqueue data for reaping.   */
  37         unsigned int            queued;    /* work has been queued */
  38 } xfs_mru_cache_t;
  39
  40 int xfs_mru_cache_init(void);
  41 void xfs_mru_cache_uninit(void);
  42 int xfs_mru_cache_create(struct xfs_mru_cache **mrup, unsigned int lifetime_ms,
  43                              unsigned int grp_count,
  44                              xfs_mru_cache_free_func_t free_func);
  45 void xfs_mru_cache_destroy(struct xfs_mru_cache *mru);
  46 int xfs_mru_cache_insert(struct xfs_mru_cache *mru, unsigned long key,
  47                                 void *value);
  48 void * xfs_mru_cache_remove(struct xfs_mru_cache *mru, unsigned long key);
  49 void xfs_mru_cache_delete(struct xfs_mru_cache *mru, unsigned long key);
  50 void *xfs_mru_cache_lookup(struct xfs_mru_cache *mru, unsigned long key);
  51 void xfs_mru_cache_done(struct xfs_mru_cache *mru);
  52
  53 #endif /* __XFS_MRU_CACHE_H__ */