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4b393c50 | 1 | /* |
716154c5 BB |
2 | * Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC. |
3 | * Copyright (C) 2007 The Regents of the University of California. | |
4 | * Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER). | |
5 | * Written by Brian Behlendorf <behlendorf1@llnl.gov>. | |
6 | * UCRL-CODE-235197 | |
7 | * | |
8 | * This file is part of the SPL, Solaris Porting Layer. | |
716154c5 BB |
9 | * |
10 | * The SPL is free software; you can redistribute it and/or modify it | |
11 | * under the terms of the GNU General Public License as published by the | |
12 | * Free Software Foundation; either version 2 of the License, or (at your | |
13 | * option) any later version. | |
14 | * | |
15 | * The SPL is distributed in the hope that it will be useful, but WITHOUT | |
16 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
17 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
18 | * for more details. | |
19 | * | |
20 | * You should have received a copy of the GNU General Public License along | |
21 | * with the SPL. If not, see <http://www.gnu.org/licenses/>. | |
4b393c50 | 22 | */ |
716154c5 | 23 | |
a9125891 BB |
24 | #ifndef _SPL_SHRINKER_H |
25 | #define _SPL_SHRINKER_H | |
baf2979e BB |
26 | |
27 | #include <linux/mm.h> | |
914b0631 | 28 | #include <linux/fs.h> |
baf2979e | 29 | |
a55bcaad | 30 | /* |
c3d9c0df | 31 | * Due to frequent changes in the shrinker API the following |
957dc103 | 32 | * compatibility wrapper should be used. |
c3d9c0df | 33 | * |
957dc103 RN |
34 | * shrinker = spl_register_shrinker(name, countfunc, scanfunc, seek_cost); |
35 | * spl_unregister_shrinker(shrinker); | |
c3d9c0df | 36 | * |
957dc103 RN |
37 | * spl_register_shrinker is used to create and register a shrinker with the |
38 | * given name. | |
270ece24 MA |
39 | * The countfunc returns the number of free-able objects. |
40 | * The scanfunc returns the number of objects that were freed. | |
41 | * The callbacks can return SHRINK_STOP if further calls can't make any more | |
42 | * progress. Note that a return value of SHRINK_EMPTY is currently not | |
43 | * supported. | |
c3d9c0df RY |
44 | * |
45 | * Example: | |
46 | * | |
270ece24 MA |
47 | * static unsigned long |
48 | * my_count(struct shrinker *shrink, struct shrink_control *sc) | |
c3d9c0df | 49 | * { |
c3d9c0df RY |
50 | * ...calculate number of objects in the cache... |
51 | * | |
52 | * return (number of objects in the cache); | |
53 | * } | |
270ece24 MA |
54 | * |
55 | * static unsigned long | |
56 | * my_scan(struct shrinker *shrink, struct shrink_control *sc) | |
57 | * { | |
58 | * ...scan objects in the cache and reclaim them... | |
59 | * } | |
60 | * | |
957dc103 | 61 | * static struct shrinker *my_shrinker; |
270ece24 MA |
62 | * |
63 | * void my_init_func(void) { | |
957dc103 RN |
64 | * my_shrinker = spl_register_shrinker("my-shrinker", |
65 | * my_count, my_scan, DEFAULT_SEEKS); | |
66 | * } | |
67 | * | |
68 | * void my_fini_func(void) { | |
69 | * spl_unregister_shrinker(my_shrinker); | |
270ece24 | 70 | * } |
a55bcaad | 71 | */ |
495bd532 | 72 | |
957dc103 RN |
73 | typedef unsigned long (*spl_shrinker_cb) |
74 | (struct shrinker *, struct shrink_control *); | |
495bd532 | 75 | |
957dc103 RN |
76 | struct shrinker *spl_register_shrinker(const char *name, |
77 | spl_shrinker_cb countfunc, spl_shrinker_cb scanfunc, int seek_cost); | |
78 | void spl_unregister_shrinker(struct shrinker *); | |
a55bcaad | 79 | |
957dc103 RN |
80 | #ifndef SHRINK_STOP |
81 | /* 3.0-3.11 compatibility */ | |
270ece24 | 82 | #define SHRINK_STOP (-1) |
c3d9c0df | 83 | #endif |
495bd532 | 84 | |
a9125891 | 85 | #endif /* SPL_SHRINKER_H */ |