Andrew Morton | 9d0243b | 2006-01-08 01:00:39 -0800 | [diff] [blame] | 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 | { |
Jan Kara | eccb95c | 2008-04-29 00:59:37 -0700 | [diff] [blame] | 17 | struct inode *inode, *toput_inode = NULL; |
Andrew Morton | 9d0243b | 2006-01-08 01:00:39 -0800 | [diff] [blame] | 18 | |
| 19 | spin_lock(&inode_lock); |
| 20 | list_for_each_entry(inode, &sb->s_inodes, i_sb_list) { |
Nick Piggin | aabb8fd | 2009-03-11 13:17:36 -0700 | [diff] [blame^] | 21 | if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) |
Andrew Morton | 9d0243b | 2006-01-08 01:00:39 -0800 | [diff] [blame] | 22 | continue; |
Jan Kara | af065b8 | 2008-04-29 00:59:39 -0700 | [diff] [blame] | 23 | if (inode->i_mapping->nrpages == 0) |
| 24 | continue; |
Jan Kara | eccb95c | 2008-04-29 00:59:37 -0700 | [diff] [blame] | 25 | __iget(inode); |
| 26 | spin_unlock(&inode_lock); |
Andrew Morton | fc9a07e | 2007-07-15 23:38:14 -0700 | [diff] [blame] | 27 | __invalidate_mapping_pages(inode->i_mapping, 0, -1, true); |
Jan Kara | eccb95c | 2008-04-29 00:59:37 -0700 | [diff] [blame] | 28 | iput(toput_inode); |
| 29 | toput_inode = inode; |
| 30 | spin_lock(&inode_lock); |
Andrew Morton | 9d0243b | 2006-01-08 01:00:39 -0800 | [diff] [blame] | 31 | } |
| 32 | spin_unlock(&inode_lock); |
Jan Kara | eccb95c | 2008-04-29 00:59:37 -0700 | [diff] [blame] | 33 | iput(toput_inode); |
Andrew Morton | 9d0243b | 2006-01-08 01:00:39 -0800 | [diff] [blame] | 34 | } |
| 35 | |
Adrian Bunk | 07d45da | 2008-04-29 00:58:57 -0700 | [diff] [blame] | 36 | static void drop_pagecache(void) |
Andrew Morton | 9d0243b | 2006-01-08 01:00:39 -0800 | [diff] [blame] | 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 | |
Adrian Bunk | 07d45da | 2008-04-29 00:58:57 -0700 | [diff] [blame] | 56 | static void drop_slab(void) |
Andrew Morton | 9d0243b | 2006-01-08 01:00:39 -0800 | [diff] [blame] | 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 | } |