mars/kernel/lib_mapfree.h

52 lines
1.3 KiB
C

// (c) 2012 Thomas Schoebel-Theuer / 1&1 Internet AG
#ifndef MARS_LIB_MAPFREE_H
#define MARS_LIB_MAPFREE_H
/* Mapfree infrastructure.
*
* Purposes:
*
* 1) Open files only once when possible, do ref-counting on struct mapfree_info
*
* 2) Automatically call invalidate_mapping_pages() in the background on
* "unused" areas to free resources.
* Used areas can be indicated by calling mapfree_set() frequently.
* Usage model: tailored to sequential logfiles.
*
* 3) Do it all in a completely decoupled manner, in order to prevent resource deadlocks.
*
* 4) Also to prevent deadlocks: always set mapping_set_gfp_mask() accordingly.
*/
#include "mars.h"
extern int mapfree_period_sec;
extern int mapfree_grace_keep_mb;
struct mapfree_info {
struct list_head mf_head;
char *mf_name;
struct file *mf_filp;
int mf_flags;
atomic_t mf_count;
spinlock_t mf_lock;
loff_t mf_min[2];
loff_t mf_last;
loff_t mf_max;
long long mf_jiffies;
};
struct mapfree_info *mapfree_get(const char *filename, int flags);
void mapfree_put(struct mapfree_info *mf);
void mapfree_set(struct mapfree_info *mf, loff_t min, loff_t max);
////////////////// module init stuff /////////////////////////
int __init init_mars_mapfree(void);
void __exit exit_mars_mapfree(void);
#endif