blob: 9cd4e4a70f56d80126c685bebe41dd7e85b0a3fc [file] [log] [blame]
Andrew Morton9d0243b2006-01-08 01:00:39 -08001/*
2 * Implement the manual drop-all-pagecache function
3 */
4
5#include <linux/kernel.h>
6#include <linux/mm.h>
7#include <linux/fs.h>
8#include <linux/writeback.h>
9#include <linux/sysctl.h>
10#include <linux/gfp.h>
11
12/* A global variable is a bit ugly, but it keeps the code simple */
13int sysctl_drop_caches;
14
15static void drop_pagecache_sb(struct super_block *sb)
16{
Jan Karaeccb95c2008-04-29 00:59:37 -070017 struct inode *inode, *toput_inode = NULL;
Andrew Morton9d0243b2006-01-08 01:00:39 -080018
19 spin_lock(&inode_lock);
20 list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
Wu Fengguangb6fac632009-04-02 16:56:34 -070021 if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE|I_NEW))
Andrew Morton9d0243b2006-01-08 01:00:39 -080022 continue;
Jan Karaaf065b82008-04-29 00:59:39 -070023 if (inode->i_mapping->nrpages == 0)
24 continue;
Jan Karaeccb95c2008-04-29 00:59:37 -070025 __iget(inode);
26 spin_unlock(&inode_lock);
Mike Waychison28697352009-06-16 15:32:59 -070027 invalidate_mapping_pages(inode->i_mapping, 0, -1);
Jan Karaeccb95c2008-04-29 00:59:37 -070028 iput(toput_inode);
29 toput_inode = inode;
30 spin_lock(&inode_lock);
Andrew Morton9d0243b2006-01-08 01:00:39 -080031 }
32 spin_unlock(&inode_lock);
Jan Karaeccb95c2008-04-29 00:59:37 -070033 iput(toput_inode);
Andrew Morton9d0243b2006-01-08 01:00:39 -080034}
35
Adrian Bunk07d45da2008-04-29 00:58:57 -070036static void drop_pagecache(void)
Andrew Morton9d0243b2006-01-08 01:00:39 -080037{
38 struct super_block *sb;
39
40 spin_lock(&sb_lock);
41restart:
42 list_for_each_entry(sb, &super_blocks, s_list) {
Al Viro551de6f2010-03-22 19:36:35 -040043 if (list_empty(&sb->s_instances))
44 continue;
Andrew Morton9d0243b2006-01-08 01:00:39 -080045 sb->s_count++;
46 spin_unlock(&sb_lock);
47 down_read(&sb->s_umount);
48 if (sb->s_root)
49 drop_pagecache_sb(sb);
50 up_read(&sb->s_umount);
51 spin_lock(&sb_lock);
52 if (__put_super_and_need_restart(sb))
53 goto restart;
54 }
55 spin_unlock(&sb_lock);
56}
57
Adrian Bunk07d45da2008-04-29 00:58:57 -070058static void drop_slab(void)
Andrew Morton9d0243b2006-01-08 01:00:39 -080059{
60 int nr_objects;
61
62 do {
63 nr_objects = shrink_slab(1000, GFP_KERNEL, 1000);
64 } while (nr_objects > 10);
65}
66
67int drop_caches_sysctl_handler(ctl_table *table, int write,
Alexey Dobriyan8d65af72009-09-23 15:57:19 -070068 void __user *buffer, size_t *length, loff_t *ppos)
Andrew Morton9d0243b2006-01-08 01:00:39 -080069{
Alexey Dobriyan8d65af72009-09-23 15:57:19 -070070 proc_dointvec_minmax(table, write, buffer, length, ppos);
Andrew Morton9d0243b2006-01-08 01:00:39 -080071 if (write) {
72 if (sysctl_drop_caches & 1)
73 drop_pagecache();
74 if (sysctl_drop_caches & 2)
75 drop_slab();
76 }
77 return 0;
78}