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Merge branch 'exec_domain_rip_v2' of git://git.kernel.org/pub/scm/linux/kernel/git...
[karo-tx-linux.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 int drop_caches_sysctl_handler(struct ctl_table *table, int write,
41         void __user *buffer, size_t *length, loff_t *ppos)
42 {
43         int ret;
44
45         ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
46         if (ret)
47                 return ret;
48         if (write) {
49                 static int stfu;
50
51                 if (sysctl_drop_caches & 1) {
52                         iterate_supers(drop_pagecache_sb, NULL);
53                         count_vm_event(DROP_PAGECACHE);
54                 }
55                 if (sysctl_drop_caches & 2) {
56                         drop_slab();
57                         count_vm_event(DROP_SLAB);
58                 }
59                 if (!stfu) {
60                         pr_info("%s (%d): drop_caches: %d\n",
61                                 current->comm, task_pid_nr(current),
62                                 sysctl_drop_caches);
63                 }
64                 stfu |= sysctl_drop_caches & 4;
65         }
66         return 0;
67 }