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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 | ||
12 | /* A global variable is a bit ugly, but it keeps the code simple */ | |
13 | int sysctl_drop_caches; | |
14 | ||
15 | static void drop_pagecache_sb(struct super_block *sb, void *unused) | |
16 | { | |
17 | struct inode *inode, *toput_inode = NULL; | |
18 | ||
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_WILL_FREE|I_NEW)) | |
22 | continue; | |
23 | if (inode->i_mapping->nrpages == 0) | |
24 | continue; | |
25 | __iget(inode); | |
26 | spin_unlock(&inode_lock); | |
27 | invalidate_mapping_pages(inode->i_mapping, 0, -1); | |
28 | iput(toput_inode); | |
29 | toput_inode = inode; | |
30 | spin_lock(&inode_lock); | |
31 | } | |
32 | spin_unlock(&inode_lock); | |
33 | iput(toput_inode); | |
34 | } | |
35 | ||
36 | static void drop_slab(void) | |
37 | { | |
38 | int nr_objects; | |
39 | ||
40 | do { | |
41 | nr_objects = shrink_slab(1000, GFP_KERNEL, 1000); | |
42 | } while (nr_objects > 10); | |
43 | } | |
44 | ||
45 | int drop_caches_sysctl_handler(ctl_table *table, int write, | |
46 | void __user *buffer, size_t *length, loff_t *ppos) | |
47 | { | |
48 | proc_dointvec_minmax(table, write, buffer, length, ppos); | |
49 | if (write) { | |
50 | if (sysctl_drop_caches & 1) | |
51 | iterate_supers(drop_pagecache_sb, NULL); | |
52 | if (sysctl_drop_caches & 2) | |
53 | drop_slab(); | |
54 | } | |
55 | return 0; | |
56 | } |