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 17 static LIST_HEAD(f2fs_list); 18 static DEFINE_SPINLOCK(f2fs_list_lock); 19 static unsigned int shrinker_run_no; 20 21 static unsigned long __count_nat_entries(struct f2fs_sb_info *sbi) 22 { 23 return NM_I(sbi)->nat_cnt - NM_I(sbi)->dirty_nat_cnt; 24 } 25 26 static unsigned long __count_free_nids(struct f2fs_sb_info *sbi) 27 { 28 if (NM_I(sbi)->fcnt > NAT_ENTRY_PER_BLOCK) 29 return NM_I(sbi)->fcnt - NAT_ENTRY_PER_BLOCK; 30 return 0; 31 } 32 33 static unsigned long __count_extent_cache(struct f2fs_sb_info *sbi) 34 { 35 return atomic_read(&sbi->total_zombie_tree) + 36 atomic_read(&sbi->total_ext_node); 37 } 38 39 unsigned long f2fs_shrink_count(struct shrinker *shrink, 40 struct shrink_control *sc) 41 { 42 struct f2fs_sb_info *sbi; 43 struct list_head *p; 44 unsigned long count = 0; 45 46 spin_lock(&f2fs_list_lock); 47 p = f2fs_list.next; 48 while (p != &f2fs_list) { 49 sbi = list_entry(p, struct f2fs_sb_info, s_list); 50 51 /* stop f2fs_put_super */ 52 if (!mutex_trylock(&sbi->umount_mutex)) { 53 p = p->next; 54 continue; 55 } 56 spin_unlock(&f2fs_list_lock); 57 58 /* count extent cache entries */ 59 count += __count_extent_cache(sbi); 60 61 /* shrink clean nat cache entries */ 62 count += __count_nat_entries(sbi); 63 64 /* count free nids cache entries */ 65 count += __count_free_nids(sbi); 66 67 spin_lock(&f2fs_list_lock); 68 p = p->next; 69 mutex_unlock(&sbi->umount_mutex); 70 } 71 spin_unlock(&f2fs_list_lock); 72 return count; 73 } 74 75 unsigned long f2fs_shrink_scan(struct shrinker *shrink, 76 struct shrink_control *sc) 77 { 78 unsigned long nr = sc->nr_to_scan; 79 struct f2fs_sb_info *sbi; 80 struct list_head *p; 81 unsigned int run_no; 82 unsigned long freed = 0; 83 84 spin_lock(&f2fs_list_lock); 85 do { 86 run_no = ++shrinker_run_no; 87 } while (run_no == 0); 88 p = f2fs_list.next; 89 while (p != &f2fs_list) { 90 sbi = list_entry(p, struct f2fs_sb_info, s_list); 91 92 if (sbi->shrinker_run_no == run_no) 93 break; 94 95 /* stop f2fs_put_super */ 96 if (!mutex_trylock(&sbi->umount_mutex)) { 97 p = p->next; 98 continue; 99 } 100 spin_unlock(&f2fs_list_lock); 101 102 sbi->shrinker_run_no = run_no; 103 104 /* shrink extent cache entries */ 105 freed += f2fs_shrink_extent_tree(sbi, nr >> 1); 106 107 /* shrink clean nat cache entries */ 108 if (freed < nr) 109 freed += try_to_free_nats(sbi, nr - freed); 110 111 /* shrink free nids cache entries */ 112 if (freed < nr) 113 freed += try_to_free_nids(sbi, nr - freed); 114 115 spin_lock(&f2fs_list_lock); 116 p = p->next; 117 list_move_tail(&sbi->s_list, &f2fs_list); 118 mutex_unlock(&sbi->umount_mutex); 119 if (freed >= nr) 120 break; 121 } 122 spin_unlock(&f2fs_list_lock); 123 return freed; 124 } 125 126 void f2fs_join_shrinker(struct f2fs_sb_info *sbi) 127 { 128 spin_lock(&f2fs_list_lock); 129 list_add_tail(&sbi->s_list, &f2fs_list); 130 spin_unlock(&f2fs_list_lock); 131 } 132 133 void f2fs_leave_shrinker(struct f2fs_sb_info *sbi) 134 { 135 f2fs_shrink_extent_tree(sbi, __count_extent_cache(sbi)); 136 137 spin_lock(&f2fs_list_lock); 138 list_del(&sbi->s_list); 139 spin_unlock(&f2fs_list_lock); 140 } 141