fs/f2fs/shrinker.c

   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 }