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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) |
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_CLEAR|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_pagecache(void) |
37 | { |
38 | struct super_block *sb; |
39 | |
40 | spin_lock(&sb_lock); |
41 | restart: |
42 | list_for_each_entry(sb, &super_blocks, s_list) { |
43 | sb->s_count++; |
44 | spin_unlock(&sb_lock); |
45 | down_read(&sb->s_umount); |
46 | if (sb->s_root) |
47 | drop_pagecache_sb(sb); |
48 | up_read(&sb->s_umount); |
49 | spin_lock(&sb_lock); |
50 | if (__put_super_and_need_restart(sb)) |
51 | goto restart; |
52 | } |
53 | spin_unlock(&sb_lock); |
54 | } |
55 | |
56 | static void drop_slab(void) |
57 | { |
58 | int nr_objects; |
59 | |
60 | do { |
61 | nr_objects = shrink_slab(1000, GFP_KERNEL, 1000); |
62 | } while (nr_objects > 10); |
63 | } |
64 | |
65 | int drop_caches_sysctl_handler(ctl_table *table, int write, |
66 | void __user *buffer, size_t *length, loff_t *ppos) |
67 | { |
68 | proc_dointvec_minmax(table, write, buffer, length, ppos); |
69 | if (write) { |
70 | if (sysctl_drop_caches & 1) |
71 | drop_pagecache(); |
72 | if (sysctl_drop_caches & 2) |
73 | drop_slab(); |
74 | } |
75 | return 0; |
76 | } |
77 |
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Tags:
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v2.6.34-rc5
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