1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * f2fs shrinker support
4 * the basic infra was copied from fs/ubifs/shrinker.c
5 *
6 * Copyright (c) 2015 Motorola Mobility
7 * Copyright (c) 2015 Jaegeuk Kim <jaegeuk@kernel.org>
8 */
9 #include <linux/fs.h>
10 #include <linux/f2fs_fs.h>
11
12 #include "f2fs.h"
13 #include "node.h"
14
15 static LIST_HEAD(f2fs_list);
16 static DEFINE_SPINLOCK(f2fs_list_lock);
17 static unsigned int shrinker_run_no;
18
19 static unsigned long __count_nat_entries(struct f2fs_sb_info *sbi)
20 {
21 return NM_I(sbi)->nat_cnt[RECLAIMABLE_NAT];
22 }
23
24 static unsigned long __count_free_nids(struct f2fs_sb_info *sbi)
25 {
26 long count = NM_I(sbi)->nid_cnt[FREE_NID] - MAX_FREE_NIDS;
27
28 return count > 0 ? count : 0;
29 }
30
31 static unsigned long __count_extent_cache(struct f2fs_sb_info *sbi,
32 enum extent_type type)
33 {
34 struct extent_tree_info *eti = &sbi->extent_tree[type];
35
36 return atomic_read(&eti->total_zombie_tree) +
37 atomic_read(&eti->total_ext_node);
38 }
39
40 unsigned long f2fs_shrink_count(struct shrinker *shrink,
41 struct shrink_control *sc)
42 {
43 struct f2fs_sb_info *sbi;
44 struct list_head *p;
45 unsigned long count = 0;
46
47 spin_lock(&f2fs_list_lock);
48 p = f2fs_list.next;
49 while (p != &f2fs_list) {
50 sbi = list_entry(p, struct f2fs_sb_info, s_list);
51
52 /* stop f2fs_put_super */
53 if (!mutex_trylock(&sbi->umount_mutex)) {
54 p = p->next;
55 continue;
56 }
57 spin_unlock(&f2fs_list_lock);
58
59 /* count read extent cache entries */
60 count += __count_extent_cache(sbi, EX_READ);
61
62 /* count block age extent cache entries */
63 count += __count_extent_cache(sbi, EX_BLOCK_AGE);
64
65 /* count clean nat cache entries */
66 count += __count_nat_entries(sbi);
67
68 /* count free nids cache entries */
69 count += __count_free_nids(sbi);
70
71 spin_lock(&f2fs_list_lock);
72 p = p->next;
73 mutex_unlock(&sbi->umount_mutex);
74 }
75 spin_unlock(&f2fs_list_lock);
76 return count;
77 }
78
79 unsigned long f2fs_shrink_scan(struct shrinker *shrink,
80 struct shrink_control *sc)
81 {
82 unsigned long nr = sc->nr_to_scan;
83 struct f2fs_sb_info *sbi;
84 struct list_head *p;
85 unsigned int run_no;
86 unsigned long freed = 0;
87
88 spin_lock(&f2fs_list_lock);
89 do {
90 run_no = ++shrinker_run_no;
91 } while (run_no == 0);
92 p = f2fs_list.next;
93 while (p != &f2fs_list) {
94 sbi = list_entry(p, struct f2fs_sb_info, s_list);
95
96 if (sbi->shrinker_run_no == run_no)
97 break;
98
99 /* stop f2fs_put_super */
100 if (!mutex_trylock(&sbi->umount_mutex)) {
101 p = p->next;
102 continue;
103 }
104 spin_unlock(&f2fs_list_lock);
105
106 sbi->shrinker_run_no = run_no;
107
108 /* shrink extent cache entries */
109 freed += f2fs_shrink_age_extent_tree(sbi, nr >> 2);
110
111 /* shrink read extent cache entries */
112 freed += f2fs_shrink_read_extent_tree(sbi, nr >> 2);
113
114 /* shrink clean nat cache entries */
115 if (freed < nr)
116 freed += f2fs_try_to_free_nats(sbi, nr - freed);
117
118 /* shrink free nids cache entries */
119 if (freed < nr)
120 freed += f2fs_try_to_free_nids(sbi, nr - freed);
121
122 spin_lock(&f2fs_list_lock);
123 p = p->next;
124 list_move_tail(&sbi->s_list, &f2fs_list);
125 mutex_unlock(&sbi->umount_mutex);
126 if (freed >= nr)
127 break;
128 }
129 spin_unlock(&f2fs_list_lock);
130 return freed;
131 }
132
133 void f2fs_join_shrinker(struct f2fs_sb_info *sbi)
134 {
135 spin_lock(&f2fs_list_lock);
136 list_add_tail(&sbi->s_list, &f2fs_list);
137 spin_unlock(&f2fs_list_lock);
138 }
139
140 void f2fs_leave_shrinker(struct f2fs_sb_info *sbi)
141 {
142 f2fs_shrink_read_extent_tree(sbi, __count_extent_cache(sbi, EX_READ));
143 f2fs_shrink_age_extent_tree(sbi,
144 __count_extent_cache(sbi, EX_BLOCK_AGE));
145
146 spin_lock(&f2fs_list_lock);
147 list_del_init(&sbi->s_list);
148 spin_unlock(&f2fs_list_lock);
149 }
150
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