projects / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 9d0243bc AM |
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 | { | |
| eccb95ce | 17 | struct inode *inode, *toput_inode = NULL; |
| 9d0243bc AM |
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)) | |
| 22 | continue; | |
| af065b8a JK |
23 | if (inode->i_mapping->nrpages == 0) |
| 24 | continue; | |
| eccb95ce JK |
25 | __iget(inode); |
| 26 | spin_unlock(&inode_lock); | |
| fc9a07e7 | 27 | __invalidate_mapping_pages(inode->i_mapping, 0, -1, true); |
| eccb95ce JK |
28 | iput(toput_inode); |
| 29 | toput_inode = inode; | |
| 30 | spin_lock(&inode_lock); | |
| 9d0243bc AM |
31 | } |
| 32 | spin_unlock(&inode_lock); | |
| eccb95ce | 33 | iput(toput_inode); |
| 9d0243bc AM |
34 | } |
| 35 | ||
| 07d45da6 | 36 | static void drop_pagecache(void) |
| 9d0243bc AM |
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 | ||
| 07d45da6 | 56 | static void drop_slab(void) |
| 9d0243bc AM |
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 | struct file *file, void __user *buffer, size_t *length, loff_t *ppos) | |
| 67 | { | |
| 68 | proc_dointvec_minmax(table, write, file, 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 | } |