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Commit | Line | Data |
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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 | } |