LXR linux/fs/xfs/xfs_mru

   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. */
  23typedef void (*xfs_mru_cache_free_func_t)(unsigned long, void*);
  24
  25typedef 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
  40int xfs_mru_cache_init(void);
  41void xfs_mru_cache_uninit(void);
  42int 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);
  45void xfs_mru_cache_destroy(struct xfs_mru_cache *mru);
  46int xfs_mru_cache_insert(struct xfs_mru_cache *mru, unsigned long key,
  47                                void *value);
  48void * xfs_mru_cache_remove(struct xfs_mru_cache *mru, unsigned long key);
  49void xfs_mru_cache_delete(struct xfs_mru_cache *mru, unsigned long key);
  50void *xfs_mru_cache_lookup(struct xfs_mru_cache *mru, unsigned long key);
  51void xfs_mru_cache_done(struct xfs_mru_cache *mru);
  52
  53#endif /* __XFS_MRU_CACHE_H__ */
  54