From 2658e50de61429f57d9496bfe371f232e2d039a1 Mon Sep 17 00:00:00 2001 From: Jaegeuk Kim Date: Fri, 19 Jun 2015 12:01:21 -0700 Subject: f2fs: introduce a shrinker for mounted fs This patch introduces a shrinker targeting to reduce memory footprint consumed by a number of in-memory f2fs data structures. In addition, it newly adds: - sbi->umount_mutex to avoid data races on shrinker and put_super - sbi->shruinker_run_no to not revisit objects Note that the basic implementation was copied from fs/ubifs/shrinker.c Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim --- fs/f2fs/shrinker.c | 104 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 104 insertions(+) create mode 100644 fs/f2fs/shrinker.c (limited to 'fs/f2fs/shrinker.c') diff --git a/fs/f2fs/shrinker.c b/fs/f2fs/shrinker.c new file mode 100644 index 000000000000..16e9b43635c2 --- /dev/null +++ b/fs/f2fs/shrinker.c @@ -0,0 +1,104 @@ +/* + * f2fs shrinker support + * the basic infra was copied from fs/ubifs/shrinker.c + * + * Copyright (c) 2015 Motorola Mobility + * Copyright (c) 2015 Jaegeuk Kim + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ +#include +#include + +#include "f2fs.h" + +static LIST_HEAD(f2fs_list); +static DEFINE_SPINLOCK(f2fs_list_lock); +static unsigned int shrinker_run_no; + +unsigned long f2fs_shrink_count(struct shrinker *shrink, + struct shrink_control *sc) +{ + struct f2fs_sb_info *sbi; + struct list_head *p; + unsigned long count = 0; + + spin_lock(&f2fs_list_lock); + p = f2fs_list.next; + while (p != &f2fs_list) { + sbi = list_entry(p, struct f2fs_sb_info, s_list); + + /* stop f2fs_put_super */ + if (!mutex_trylock(&sbi->umount_mutex)) { + p = p->next; + continue; + } + spin_unlock(&f2fs_list_lock); + + /* TODO: count # of objects */ + + spin_lock(&f2fs_list_lock); + p = p->next; + mutex_unlock(&sbi->umount_mutex); + } + spin_unlock(&f2fs_list_lock); + return count; +} + +unsigned long f2fs_shrink_scan(struct shrinker *shrink, + struct shrink_control *sc) +{ + unsigned long nr = sc->nr_to_scan; + struct f2fs_sb_info *sbi; + struct list_head *p; + unsigned int run_no; + unsigned long freed = 0; + + spin_lock(&f2fs_list_lock); + do { + run_no = ++shrinker_run_no; + } while (run_no == 0); + p = f2fs_list.next; + while (p != &f2fs_list) { + sbi = list_entry(p, struct f2fs_sb_info, s_list); + + if (sbi->shrinker_run_no == run_no) + break; + + /* stop f2fs_put_super */ + if (!mutex_trylock(&sbi->umount_mutex)) { + p = p->next; + continue; + } + spin_unlock(&f2fs_list_lock); + + sbi->shrinker_run_no = run_no; + + /* TODO: shrink caches */ + + spin_lock(&f2fs_list_lock); + p = p->next; + list_move_tail(&sbi->s_list, &f2fs_list); + mutex_unlock(&sbi->umount_mutex); + if (freed >= nr) + break; + } + spin_unlock(&f2fs_list_lock); + return freed; +} + +void f2fs_join_shrinker(struct f2fs_sb_info *sbi) +{ + spin_lock(&f2fs_list_lock); + list_add_tail(&sbi->s_list, &f2fs_list); + spin_unlock(&f2fs_list_lock); +} + +void f2fs_leave_shrinker(struct f2fs_sb_info *sbi) +{ + spin_lock(&f2fs_list_lock); + list_del(&sbi->s_list); + spin_unlock(&f2fs_list_lock); +} -- cgit v1.2.3