Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
[platform/adaptation/renesas_rcar/renesas_kernel.git] / fs / drop_caches.c
1 /*
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 #include "internal.h"
12
13 /* A global variable is a bit ugly, but it keeps the code simple */
14 int sysctl_drop_caches;
15
16 static void drop_pagecache_sb(struct super_block *sb, void *unused)
17 {
18         struct inode *inode, *toput_inode = NULL;
19
20         spin_lock(&inode_sb_list_lock);
21         list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
22                 spin_lock(&inode->i_lock);
23                 if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
24                     (inode->i_mapping->nrpages == 0)) {
25                         spin_unlock(&inode->i_lock);
26                         continue;
27                 }
28                 __iget(inode);
29                 spin_unlock(&inode->i_lock);
30                 spin_unlock(&inode_sb_list_lock);
31                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
32                 iput(toput_inode);
33                 toput_inode = inode;
34                 spin_lock(&inode_sb_list_lock);
35         }
36         spin_unlock(&inode_sb_list_lock);
37         iput(toput_inode);
38 }
39
40 static void drop_slab(void)
41 {
42         int nr_objects;
43         struct shrink_control shrink = {
44                 .gfp_mask = GFP_KERNEL,
45         };
46
47         do {
48                 nr_objects = shrink_slab(&shrink, 1000, 1000);
49         } while (nr_objects > 10);
50 }
51
52 int drop_caches_sysctl_handler(ctl_table *table, int write,
53         void __user *buffer, size_t *length, loff_t *ppos)
54 {
55         int ret;
56
57         ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
58         if (ret)
59                 return ret;
60         if (write) {
61                 if (sysctl_drop_caches & 1)
62                         iterate_supers(drop_pagecache_sb, NULL);
63                 if (sysctl_drop_caches & 2)
64                         drop_slab();
65         }
66         return 0;
67 }