86 lines
2.6 KiB
C
86 lines
2.6 KiB
C
/*
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* Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
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* Copyright (C) 2007 The Regents of the University of California.
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* Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
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* Written by Brian Behlendorf <behlendorf1@llnl.gov>.
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* UCRL-CODE-235197
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*
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* This file is part of the SPL, Solaris Porting Layer.
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*
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* The SPL is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*
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* The SPL is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with the SPL. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef _SPL_SHRINKER_H
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#define _SPL_SHRINKER_H
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#include <linux/mm.h>
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#include <linux/fs.h>
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/*
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* Due to frequent changes in the shrinker API the following
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* compatibility wrapper should be used.
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*
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* shrinker = spl_register_shrinker(name, countfunc, scanfunc, seek_cost);
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* spl_unregister_shrinker(shrinker);
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*
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* spl_register_shrinker is used to create and register a shrinker with the
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* given name.
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* The countfunc returns the number of free-able objects.
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* The scanfunc returns the number of objects that were freed.
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* The callbacks can return SHRINK_STOP if further calls can't make any more
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* progress. Note that a return value of SHRINK_EMPTY is currently not
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* supported.
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*
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* Example:
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*
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* static unsigned long
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* my_count(struct shrinker *shrink, struct shrink_control *sc)
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* {
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* ...calculate number of objects in the cache...
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*
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* return (number of objects in the cache);
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* }
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*
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* static unsigned long
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* my_scan(struct shrinker *shrink, struct shrink_control *sc)
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* {
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* ...scan objects in the cache and reclaim them...
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* }
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*
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* static struct shrinker *my_shrinker;
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*
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* void my_init_func(void) {
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* my_shrinker = spl_register_shrinker("my-shrinker",
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* my_count, my_scan, DEFAULT_SEEKS);
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* }
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*
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* void my_fini_func(void) {
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* spl_unregister_shrinker(my_shrinker);
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* }
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*/
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typedef unsigned long (*spl_shrinker_cb)
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(struct shrinker *, struct shrink_control *);
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struct shrinker *spl_register_shrinker(const char *name,
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spl_shrinker_cb countfunc, spl_shrinker_cb scanfunc, int seek_cost);
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void spl_unregister_shrinker(struct shrinker *);
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#ifndef SHRINK_STOP
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/* 3.0-3.11 compatibility */
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#define SHRINK_STOP (-1)
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#endif
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#endif /* SPL_SHRINKER_H */
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