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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(&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 | } |
68 |
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Tags:
od-2011-09-04
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