2 * Implement the manual drop-all-pagecache function
5 #include <linux/kernel.h>
8 #include <linux/writeback.h>
9 #include <linux/sysctl.h>
10 #include <linux/gfp.h>
12 /* A global variable is a bit ugly, but it keeps the code simple */
13 int sysctl_drop_caches
;
15 static void drop_pagecache_sb(struct super_block
*sb
)
17 struct inode
*inode
, *toput_inode
= NULL
;
19 spin_lock(&inode_lock
);
20 list_for_each_entry(inode
, &sb
->s_inodes
, i_sb_list
) {
21 if (inode
->i_state
& (I_FREEING
|I_CLEAR
|I_WILL_FREE
|I_NEW
))
23 if (inode
->i_mapping
->nrpages
== 0)
26 spin_unlock(&inode_lock
);
27 invalidate_mapping_pages(inode
->i_mapping
, 0, -1);
30 spin_lock(&inode_lock
);
32 spin_unlock(&inode_lock
);
36 static void drop_pagecache(void)
38 struct super_block
*sb
;
42 list_for_each_entry(sb
, &super_blocks
, s_list
) {
44 spin_unlock(&sb_lock
);
45 down_read(&sb
->s_umount
);
47 drop_pagecache_sb(sb
);
48 up_read(&sb
->s_umount
);
50 if (__put_super_and_need_restart(sb
))
53 spin_unlock(&sb_lock
);
56 static void drop_slab(void)
61 nr_objects
= shrink_slab(1000, GFP_KERNEL
, 1000);
62 } while (nr_objects
> 10);
65 int drop_caches_sysctl_handler(ctl_table
*table
, int write
,
66 void __user
*buffer
, size_t *length
, loff_t
*ppos
)
68 proc_dointvec_minmax(table
, write
, buffer
, length
, ppos
);
70 if (sysctl_drop_caches
& 1)
72 if (sysctl_drop_caches
& 2)