141 lines
3.2 KiB
C
141 lines
3.2 KiB
C
/*
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* f2fs shrinker support
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* the basic infra was copied from fs/ubifs/shrinker.c
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*
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* Copyright (c) 2015 Motorola Mobility
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* Copyright (c) 2015 Jaegeuk Kim <jaegeuk@kernel.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/fs.h>
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#include <linux/f2fs_fs.h>
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#include "f2fs.h"
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static LIST_HEAD(f2fs_list);
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static DEFINE_SPINLOCK(f2fs_list_lock);
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static unsigned int shrinker_run_no;
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static unsigned long __count_nat_entries(struct f2fs_sb_info *sbi)
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{
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return NM_I(sbi)->nat_cnt - NM_I(sbi)->dirty_nat_cnt;
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}
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static unsigned long __count_free_nids(struct f2fs_sb_info *sbi)
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{
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if (NM_I(sbi)->fcnt > NAT_ENTRY_PER_BLOCK)
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return NM_I(sbi)->fcnt - NAT_ENTRY_PER_BLOCK;
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return 0;
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}
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static unsigned long __count_extent_cache(struct f2fs_sb_info *sbi)
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{
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return atomic_read(&sbi->total_zombie_tree) +
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atomic_read(&sbi->total_ext_node);
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}
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unsigned long f2fs_shrink_count(struct shrinker *shrink,
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struct shrink_control *sc)
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{
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struct f2fs_sb_info *sbi;
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struct list_head *p;
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unsigned long count = 0;
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spin_lock(&f2fs_list_lock);
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p = f2fs_list.next;
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while (p != &f2fs_list) {
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sbi = list_entry(p, struct f2fs_sb_info, s_list);
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/* stop f2fs_put_super */
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if (!mutex_trylock(&sbi->umount_mutex)) {
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p = p->next;
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continue;
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}
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spin_unlock(&f2fs_list_lock);
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/* count extent cache entries */
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count += __count_extent_cache(sbi);
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/* shrink clean nat cache entries */
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count += __count_nat_entries(sbi);
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/* count free nids cache entries */
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count += __count_free_nids(sbi);
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spin_lock(&f2fs_list_lock);
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p = p->next;
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mutex_unlock(&sbi->umount_mutex);
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}
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spin_unlock(&f2fs_list_lock);
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return count;
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}
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unsigned long f2fs_shrink_scan(struct shrinker *shrink,
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struct shrink_control *sc)
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{
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unsigned long nr = sc->nr_to_scan;
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struct f2fs_sb_info *sbi;
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struct list_head *p;
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unsigned int run_no;
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unsigned long freed = 0;
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spin_lock(&f2fs_list_lock);
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do {
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run_no = ++shrinker_run_no;
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} while (run_no == 0);
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p = f2fs_list.next;
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while (p != &f2fs_list) {
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sbi = list_entry(p, struct f2fs_sb_info, s_list);
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if (sbi->shrinker_run_no == run_no)
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break;
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/* stop f2fs_put_super */
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if (!mutex_trylock(&sbi->umount_mutex)) {
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p = p->next;
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continue;
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}
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spin_unlock(&f2fs_list_lock);
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sbi->shrinker_run_no = run_no;
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/* shrink extent cache entries */
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freed += f2fs_shrink_extent_tree(sbi, nr >> 1);
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/* shrink clean nat cache entries */
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if (freed < nr)
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freed += try_to_free_nats(sbi, nr - freed);
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/* shrink free nids cache entries */
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if (freed < nr)
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freed += try_to_free_nids(sbi, nr - freed);
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spin_lock(&f2fs_list_lock);
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p = p->next;
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list_move_tail(&sbi->s_list, &f2fs_list);
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mutex_unlock(&sbi->umount_mutex);
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if (freed >= nr)
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break;
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}
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spin_unlock(&f2fs_list_lock);
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return freed;
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}
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void f2fs_join_shrinker(struct f2fs_sb_info *sbi)
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{
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spin_lock(&f2fs_list_lock);
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list_add_tail(&sbi->s_list, &f2fs_list);
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spin_unlock(&f2fs_list_lock);
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}
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void f2fs_leave_shrinker(struct f2fs_sb_info *sbi)
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{
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f2fs_shrink_extent_tree(sbi, __count_extent_cache(sbi));
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spin_lock(&f2fs_list_lock);
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list_del(&sbi->s_list);
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spin_unlock(&f2fs_list_lock);
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}
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