Commit 2658e50d authored by Jaegeuk Kim's avatar Jaegeuk Kim

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: default avatarChao Yu <chao2.yu@samsung.com>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent 244f4fc1
......@@ -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
......
......@@ -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;
};
/*
......@@ -1951,6 +1956,14 @@ bool f2fs_empty_inline_dir(struct inode *);
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
*/
......
/*
* 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;
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);
}
......@@ -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 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
goto free_nm;
}
f2fs_join_shrinker(sbi);
/* if there are nt orphan nodes free them */
recover_orphan_inodes(sbi);
......@@ -1310,7 +1328,10 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
dput(sb->s_root);
sb->s_root = NULL;
free_node_inode:
mutex_lock(&sbi->umount_mutex);
f2fs_leave_shrinker(sbi);
iput(sbi->node_inode);
mutex_unlock(&sbi->umount_mutex);
free_nm:
destroy_node_manager(sbi);
free_sm:
......@@ -1406,13 +1427,20 @@ static int __init init_f2fs_fs(void)
err = f2fs_init_crypto();
if (err)
goto free_kset;
err = register_filesystem(&f2fs_fs_type);
err = register_shrinker(&f2fs_shrinker_info);
if (err)
goto free_crypto;
err = register_filesystem(&f2fs_fs_type);
if (err)
goto free_shrinker;
f2fs_create_root_stats();
f2fs_proc_root = proc_mkdir("fs/f2fs", NULL);
return 0;
free_shrinker:
unregister_shrinker(&f2fs_shrinker_info);
free_crypto:
f2fs_exit_crypto();
free_kset:
......@@ -1435,6 +1463,7 @@ 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();
......
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