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