blob: b6a719a909f8eee1829764ea770e879c1c9c73fe [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);
Andrew Mortonfc9a07e2007-07-15 23:38:14 -070027 __invalidate_mapping_pages(inode->i_mapping, 0, -1, true);
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) {
43 sb->s_count++;
44 spin_unlock(&sb_lock);
45 down_read(&sb->s_umount);
46 if (sb->s_root)
47 drop_pagecache_sb(sb);
48 up_read(&sb->s_umount);
49 spin_lock(&sb_lock);
50 if (__put_super_and_need_restart(sb))
51 goto restart;
52 }
53 spin_unlock(&sb_lock);
54}
55
Adrian Bunk07d45da2008-04-29 00:58:57 -070056static void drop_slab(void)
Andrew Morton9d0243b2006-01-08 01:00:39 -080057{
58 int nr_objects;
59
60 do {
61 nr_objects = shrink_slab(1000, GFP_KERNEL, 1000);
62 } while (nr_objects > 10);
63}
64
65int drop_caches_sysctl_handler(ctl_table *table, int write,
66 struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
67{
68 proc_dointvec_minmax(table, write, file, buffer, length, ppos);
69 if (write) {
70 if (sysctl_drop_caches & 1)
71 drop_pagecache();
72 if (sysctl_drop_caches & 2)
73 drop_slab();
74 }
75 return 0;
76}