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Date: Mon, 29 Jun 2015 11:39:32 -0700
From: Jaegeuk Kim <jaegeuk@...nel.org>
To: linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
linux-f2fs-devel@...ts.sourceforge.net
Cc: Jaegeuk Kim <jaegeuk@...nel.org>
Subject: [PATCH 08/12] 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
Noteh that the basic implementation was copied from fs/btrfs/shrinker.c
Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
---
fs/f2fs/Makefile | 1 +
fs/f2fs/f2fs.h | 13 +++++++
fs/f2fs/shrinker.c | 104 +++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/f2fs/super.c | 24 +++++++++++++
4 files changed, 142 insertions(+)
create mode 100644 fs/f2fs/shrinker.c
diff --git a/fs/f2fs/Makefile b/fs/f2fs/Makefile
index 396be1a..005251b 100644
--- a/fs/f2fs/Makefile
+++ b/fs/f2fs/Makefile
@@ -2,6 +2,7 @@ obj-$(CONFIG_F2FS_FS) += f2fs.o
f2fs-y := dir.o file.o inode.o namei.o hash.o super.o inline.o
f2fs-y += checkpoint.o gc.o data.o node.o segment.o recovery.o
+f2fs-y += shrinker.o
f2fs-$(CONFIG_F2FS_STAT_FS) += debug.o
f2fs-$(CONFIG_F2FS_FS_XATTR) += xattr.o
f2fs-$(CONFIG_F2FS_FS_POSIX_ACL) += acl.o
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 3aaa4b9..e82af8c 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -791,6 +791,11 @@ struct f2fs_sb_info {
/* For sysfs suppport */
struct kobject s_kobj;
struct completion s_kobj_unregister;
+
+ /* For shrinker support */
+ struct list_head s_list;
+ struct mutex umount_mutex;
+ unsigned int shrinker_run_no;
};
/*
@@ -1952,6 +1957,14 @@ int f2fs_read_inline_dir(struct file *, struct dir_context *,
struct f2fs_str *);
/*
+ * shrinker.c
+ */
+unsigned long f2fs_shrink_count(struct shrinker *, struct shrink_control *);
+unsigned long f2fs_shrink_scan(struct shrinker *, struct shrink_control *);
+void f2fs_join_shrinker(struct f2fs_sb_info *);
+void f2fs_leave_shrinker(struct f2fs_sb_info *);
+
+/*
* crypto support
*/
static inline int f2fs_encrypted_inode(struct inode *inode)
diff --git a/fs/f2fs/shrinker.c b/fs/f2fs/shrinker.c
new file mode 100644
index 0000000..a680145
--- /dev/null
+++ b/fs/f2fs/shrinker.c
@@ -0,0 +1,104 @@
+/*
+ * f2fs shrinker support
+ * the basic infra was copied from fs/btrfs/shrinker.c
+ *
+ * Copyright (c) 2015 Motorola Mobility
+ * Copyright (c) 2015 Jaegeuk Kim <jaegeuk@...nel.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;
+
+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);
+}
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index da27710..2e8645e 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -39,6 +39,13 @@ static struct proc_dir_entry *f2fs_proc_root;
static struct kmem_cache *f2fs_inode_cachep;
static struct kset *f2fs_kset;
+/* f2fs-wide shrinker description */
+static struct shrinker f2fs_shrinker_info = {
+ .scan_objects = f2fs_shrink_scan,
+ .count_objects = f2fs_shrink_count,
+ .seeks = DEFAULT_SEEKS,
+};
+
enum {
Opt_gc_background,
Opt_disable_roll_forward,
@@ -500,6 +507,9 @@ static void f2fs_put_super(struct super_block *sb)
stop_gc_thread(sbi);
+ /* prevent remaining shrinker jobs */
+ mutex_lock(&sbi->umount_mutex);
+
/*
* We don't need to do checkpoint when superblock is clean.
* But, the previous checkpoint was not done by umount, it needs to do
@@ -523,6 +533,9 @@ static void f2fs_put_super(struct super_block *sb)
release_dirty_inode(sbi);
release_discard_addrs(sbi);
+ f2fs_leave_shrinker(sbi);
+ mutex_unlock(&sbi->umount_mutex);
+
iput(sbi->node_inode);
iput(sbi->meta_inode);
@@ -972,6 +985,9 @@ static void init_sb_info(struct f2fs_sb_info *sbi)
sbi->dir_level = DEF_DIR_LEVEL;
clear_sbi_flag(sbi, SBI_NEED_FSCK);
+
+ INIT_LIST_HEAD(&sbi->s_list);
+ mutex_init(&sbi->umount_mutex);
}
/*
@@ -1214,6 +1230,8 @@ try_onemore:
goto free_nm;
}
+ f2fs_join_shrinker(sbi);
+
/* if there are nt orphan nodes free them */
recover_orphan_inodes(sbi);
@@ -1310,6 +1328,7 @@ free_root_inode:
dput(sb->s_root);
sb->s_root = NULL;
free_node_inode:
+ f2fs_leave_shrinker(sbi);
iput(sbi->node_inode);
free_nm:
destroy_node_manager(sbi);
@@ -1406,6 +1425,9 @@ static int __init init_f2fs_fs(void)
err = f2fs_init_crypto();
if (err)
goto free_kset;
+
+ register_shrinker(&f2fs_shrinker_info);
+
err = register_filesystem(&f2fs_fs_type);
if (err)
goto free_crypto;
@@ -1414,6 +1436,7 @@ static int __init init_f2fs_fs(void)
return 0;
free_crypto:
+ unregister_shrinker(&f2fs_shrinker_info);
f2fs_exit_crypto();
free_kset:
kset_unregister(f2fs_kset);
@@ -1435,6 +1458,7 @@ static void __exit exit_f2fs_fs(void)
{
remove_proc_entry("fs/f2fs", NULL);
f2fs_destroy_root_stats();
+ unregister_shrinker(&f2fs_shrinker_info);
unregister_filesystem(&f2fs_fs_type);
f2fs_exit_crypto();
destroy_extent_cache();
--
2.1.1
--
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