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Merge tag 'drm-misc-fixes-2017-07-27' of git://anongit.freedesktop.org/git/drm-misc...
[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(&sb->s_inode_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(&sb->s_inode_list_lock);
31
32                 invalidate_mapping_pages(inode->i_mapping, 0, -1);
33                 iput(toput_inode);
34                 toput_inode = inode;
35
36                 spin_lock(&sb->s_inode_list_lock);
37         }
38         spin_unlock(&sb->s_inode_list_lock);
39         iput(toput_inode);
40 }
41
42 int drop_caches_sysctl_handler(struct ctl_table *table, int write,
43         void __user *buffer, size_t *length, loff_t *ppos)
44 {
45         int ret;
46
47         ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
48         if (ret)
49                 return ret;
50         if (write) {
51                 static int stfu;
52
53                 if (sysctl_drop_caches & 1) {
54                         iterate_supers(drop_pagecache_sb, NULL);
55                         count_vm_event(DROP_PAGECACHE);
56                 }
57                 if (sysctl_drop_caches & 2) {
58                         drop_slab();
59                         count_vm_event(DROP_SLAB);
60                 }
61                 if (!stfu) {
62                         pr_info("%s (%d): drop_caches: %d\n",
63                                 current->comm, task_pid_nr(current),
64                                 sysctl_drop_caches);
65                 }
66                 stfu |= sysctl_drop_caches & 4;
67         }
68         return 0;
69 }