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-rw-r--r--fs/f2fs/shrinker.c139
1 files changed, 139 insertions, 0 deletions
diff --git a/fs/f2fs/shrinker.c b/fs/f2fs/shrinker.c
new file mode 100644
index 000000000000..da0d8e0b55a5
--- /dev/null
+++ b/fs/f2fs/shrinker.c
@@ -0,0 +1,139 @@
+/*
+ * f2fs shrinker support
+ * the basic infra was copied from fs/ubifs/shrinker.c
+ *
+ * Copyright (c) 2015 Motorola Mobility
+ * Copyright (c) 2015 Jaegeuk Kim <jaegeuk@kernel.org>
+ *
+ * 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 <linux/fs.h>
+#include <linux/f2fs_fs.h>
+
+#include "f2fs.h"
+
+static LIST_HEAD(f2fs_list);
+static DEFINE_SPINLOCK(f2fs_list_lock);
+static unsigned int shrinker_run_no;
+
+static unsigned long __count_nat_entries(struct f2fs_sb_info *sbi)
+{
+ return NM_I(sbi)->nat_cnt - NM_I(sbi)->dirty_nat_cnt;
+}
+
+static unsigned long __count_free_nids(struct f2fs_sb_info *sbi)
+{
+ if (NM_I(sbi)->fcnt > NAT_ENTRY_PER_BLOCK)
+ return NM_I(sbi)->fcnt - NAT_ENTRY_PER_BLOCK;
+ return 0;
+}
+
+static unsigned long __count_extent_cache(struct f2fs_sb_info *sbi)
+{
+ return sbi->total_ext_tree + atomic_read(&sbi->total_ext_node);
+}
+
+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);
+
+ /* count extent cache entries */
+ count += __count_extent_cache(sbi);
+
+ /* shrink clean nat cache entries */
+ count += __count_nat_entries(sbi);
+
+ /* count free nids cache entries */
+ count += __count_free_nids(sbi);
+
+ 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;
+
+ /* shrink extent cache entries */
+ freed += f2fs_shrink_extent_tree(sbi, nr >> 1);
+
+ /* shrink clean nat cache entries */
+ if (freed < nr)
+ freed += try_to_free_nats(sbi, nr - freed);
+
+ /* shrink free nids cache entries */
+ if (freed < nr)
+ freed += try_to_free_nids(sbi, nr - freed);
+
+ 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)
+{
+ f2fs_shrink_extent_tree(sbi, __count_extent_cache(sbi));
+
+ spin_lock(&f2fs_list_lock);
+ list_del(&sbi->s_list);
+ spin_unlock(&f2fs_list_lock);
+}