fs/f2fs/shrinker.c

   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 {
  33         return atomic_read(&sbi->total_zombie_tree) +
  34                                 atomic_read(&sbi->total_ext_node);
  35 }
  36
  37 unsigned long f2fs_shrink_count(struct shrinker *shrink,
  38                                 struct shrink_control *sc)
  39 {
  40         struct f2fs_sb_info *sbi;
  41         struct list_head *p;
  42         unsigned long count = 0;
  43
  44         spin_lock(&f2fs_list_lock);
  45         p = f2fs_list.next;
  46         while (p != &f2fs_list) {
  47                 sbi = list_entry(p, struct f2fs_sb_info, s_list);
  48
  49                 /* stop f2fs_put_super */
  50                 if (!mutex_trylock(&sbi->umount_mutex)) {
  51                         p = p->next;
  52                         continue;
  53                 }
  54                 spin_unlock(&f2fs_list_lock);
  55
  56                 /* count extent cache entries */
  57                 count += __count_extent_cache(sbi);
  58
  59                 /* count clean nat cache entries */
  60                 count += __count_nat_entries(sbi);
  61
  62                 /* count free nids cache entries */
  63                 count += __count_free_nids(sbi);
  64
  65                 spin_lock(&f2fs_list_lock);
  66                 p = p->next;
  67                 mutex_unlock(&sbi->umount_mutex);
  68         }
  69         spin_unlock(&f2fs_list_lock);
  70         return count;
  71 }
  72
  73 unsigned long f2fs_shrink_scan(struct shrinker *shrink,
  74                                 struct shrink_control *sc)
  75 {
  76         unsigned long nr = sc->nr_to_scan;
  77         struct f2fs_sb_info *sbi;
  78         struct list_head *p;
  79         unsigned int run_no;
  80         unsigned long freed = 0;
  81
  82         spin_lock(&f2fs_list_lock);
  83         do {
  84                 run_no = ++shrinker_run_no;
  85         } while (run_no == 0);
  86         p = f2fs_list.next;
  87         while (p != &f2fs_list) {
  88                 sbi = list_entry(p, struct f2fs_sb_info, s_list);
  89
  90                 if (sbi->shrinker_run_no == run_no)
  91                         break;
  92
  93                 /* stop f2fs_put_super */
  94                 if (!mutex_trylock(&sbi->umount_mutex)) {
  95                         p = p->next;
  96                         continue;
  97                 }
  98                 spin_unlock(&f2fs_list_lock);
  99
 100                 sbi->shrinker_run_no = run_no;
 101
 102                 /* shrink extent cache entries */
 103                 freed += f2fs_shrink_extent_tree(sbi, nr >> 1);
 104
 105                 /* shrink clean nat cache entries */
 106                 if (freed < nr)
 107                         freed += f2fs_try_to_free_nats(sbi, nr - freed);
 108
 109                 /* shrink free nids cache entries */
 110                 if (freed < nr)
 111                         freed += f2fs_try_to_free_nids(sbi, nr - freed);
 112
 113                 spin_lock(&f2fs_list_lock);
 114                 p = p->next;
 115                 list_move_tail(&sbi->s_list, &f2fs_list);
 116                 mutex_unlock(&sbi->umount_mutex);
 117                 if (freed >= nr)
 118                         break;
 119         }
 120         spin_unlock(&f2fs_list_lock);
 121         return freed;
 122 }
 123
 124 void f2fs_join_shrinker(struct f2fs_sb_info *sbi)
 125 {
 126         spin_lock(&f2fs_list_lock);
 127         list_add_tail(&sbi->s_list, &f2fs_list);
 128         spin_unlock(&f2fs_list_lock);
 129 }
 130
 131 void f2fs_leave_shrinker(struct f2fs_sb_info *sbi)
 132 {
 133         f2fs_shrink_extent_tree(sbi, __count_extent_cache(sbi));
 134
 135         spin_lock(&f2fs_list_lock);
 136         list_del_init(&sbi->s_list);
 137         spin_unlock(&f2fs_list_lock);
 138 }