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1 | /* | |
2 | * f2fs shrinker support | |
3 | * the basic infra was copied from fs/ubifs/shrinker.c | |
4 | * | |
5 | * Copyright (c) 2015 Motorola Mobility | |
6 | * Copyright (c) 2015 Jaegeuk Kim <jaegeuk@kernel.org> | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | */ | |
12 | #include <linux/fs.h> | |
13 | #include <linux/f2fs_fs.h> | |
14 | ||
15 | #include "f2fs.h" | |
16 | #include "node.h" | |
17 | ||
18 | static LIST_HEAD(f2fs_list); | |
19 | static DEFINE_SPINLOCK(f2fs_list_lock); | |
20 | static unsigned int shrinker_run_no; | |
21 | ||
22 | static unsigned long __count_nat_entries(struct f2fs_sb_info *sbi) | |
23 | { | |
24 | long count = NM_I(sbi)->nat_cnt - NM_I(sbi)->dirty_nat_cnt; | |
25 | ||
26 | return count > 0 ? count : 0; | |
27 | } | |
28 | ||
29 | static unsigned long __count_free_nids(struct f2fs_sb_info *sbi) | |
30 | { | |
31 | long count = NM_I(sbi)->nid_cnt[FREE_NID_LIST] - MAX_FREE_NIDS; | |
32 | ||
33 | return count > 0 ? count : 0; | |
34 | } | |
35 | ||
36 | static unsigned long __count_extent_cache(struct f2fs_sb_info *sbi) | |
37 | { | |
38 | return atomic_read(&sbi->total_zombie_tree) + | |
39 | atomic_read(&sbi->total_ext_node); | |
40 | } | |
41 | ||
42 | unsigned long f2fs_shrink_count(struct shrinker *shrink, | |
43 | struct shrink_control *sc) | |
44 | { | |
45 | struct f2fs_sb_info *sbi; | |
46 | struct list_head *p; | |
47 | unsigned long count = 0; | |
48 | ||
49 | spin_lock(&f2fs_list_lock); | |
50 | p = f2fs_list.next; | |
51 | while (p != &f2fs_list) { | |
52 | sbi = list_entry(p, struct f2fs_sb_info, s_list); | |
53 | ||
54 | /* stop f2fs_put_super */ | |
55 | if (!mutex_trylock(&sbi->umount_mutex)) { | |
56 | p = p->next; | |
57 | continue; | |
58 | } | |
59 | spin_unlock(&f2fs_list_lock); | |
60 | ||
61 | /* count extent cache entries */ | |
62 | count += __count_extent_cache(sbi); | |
63 | ||
64 | /* shrink clean nat cache entries */ | |
65 | count += __count_nat_entries(sbi); | |
66 | ||
67 | /* count free nids cache entries */ | |
68 | count += __count_free_nids(sbi); | |
69 | ||
70 | spin_lock(&f2fs_list_lock); | |
71 | p = p->next; | |
72 | mutex_unlock(&sbi->umount_mutex); | |
73 | } | |
74 | spin_unlock(&f2fs_list_lock); | |
75 | return count; | |
76 | } | |
77 | ||
78 | unsigned long f2fs_shrink_scan(struct shrinker *shrink, | |
79 | struct shrink_control *sc) | |
80 | { | |
81 | unsigned long nr = sc->nr_to_scan; | |
82 | struct f2fs_sb_info *sbi; | |
83 | struct list_head *p; | |
84 | unsigned int run_no; | |
85 | unsigned long freed = 0; | |
86 | ||
87 | spin_lock(&f2fs_list_lock); | |
88 | do { | |
89 | run_no = ++shrinker_run_no; | |
90 | } while (run_no == 0); | |
91 | p = f2fs_list.next; | |
92 | while (p != &f2fs_list) { | |
93 | sbi = list_entry(p, struct f2fs_sb_info, s_list); | |
94 | ||
95 | if (sbi->shrinker_run_no == run_no) | |
96 | break; | |
97 | ||
98 | /* stop f2fs_put_super */ | |
99 | if (!mutex_trylock(&sbi->umount_mutex)) { | |
100 | p = p->next; | |
101 | continue; | |
102 | } | |
103 | spin_unlock(&f2fs_list_lock); | |
104 | ||
105 | sbi->shrinker_run_no = run_no; | |
106 | ||
107 | /* shrink extent cache entries */ | |
108 | freed += f2fs_shrink_extent_tree(sbi, nr >> 1); | |
109 | ||
110 | /* shrink clean nat cache entries */ | |
111 | if (freed < nr) | |
112 | freed += try_to_free_nats(sbi, nr - freed); | |
113 | ||
114 | /* shrink free nids cache entries */ | |
115 | if (freed < nr) | |
116 | freed += try_to_free_nids(sbi, nr - freed); | |
117 | ||
118 | spin_lock(&f2fs_list_lock); | |
119 | p = p->next; | |
120 | list_move_tail(&sbi->s_list, &f2fs_list); | |
121 | mutex_unlock(&sbi->umount_mutex); | |
122 | if (freed >= nr) | |
123 | break; | |
124 | } | |
125 | spin_unlock(&f2fs_list_lock); | |
126 | return freed; | |
127 | } | |
128 | ||
129 | void f2fs_join_shrinker(struct f2fs_sb_info *sbi) | |
130 | { | |
131 | spin_lock(&f2fs_list_lock); | |
132 | list_add_tail(&sbi->s_list, &f2fs_list); | |
133 | spin_unlock(&f2fs_list_lock); | |
134 | } | |
135 | ||
136 | void f2fs_leave_shrinker(struct f2fs_sb_info *sbi) | |
137 | { | |
138 | f2fs_shrink_extent_tree(sbi, __count_extent_cache(sbi)); | |
139 | ||
140 | spin_lock(&f2fs_list_lock); | |
141 | list_del(&sbi->s_list); | |
142 | spin_unlock(&f2fs_list_lock); | |
143 | } |