2 * Implement the manual drop-all-pagecache function
5 #include <linux/kernel.h>
8 #include <linux/writeback.h>
9 #include <linux/sysctl.h>
10 #include <linux/gfp.h>
13 /* A global variable is a bit ugly, but it keeps the code simple */
14 int sysctl_drop_caches;
16 static void drop_pagecache_sb(struct super_block *sb, void *unused)
18 struct inode *inode, *toput_inode = NULL;
20 spin_lock(&sb->s_inode_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);
29 spin_unlock(&inode->i_lock);
30 spin_unlock(&sb->s_inode_list_lock);
32 invalidate_mapping_pages(inode->i_mapping, 0, -1);
36 spin_lock(&sb->s_inode_list_lock);
38 spin_unlock(&sb->s_inode_list_lock);
42 int drop_caches_sysctl_handler(struct ctl_table *table, int write,
43 void __user *buffer, size_t *length, loff_t *ppos)
47 ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
53 if (sysctl_drop_caches & 1) {
54 iterate_supers(drop_pagecache_sb, NULL);
55 count_vm_event(DROP_PAGECACHE);
57 if (sysctl_drop_caches & 2) {
59 count_vm_event(DROP_SLAB);
62 pr_info("%s (%d): drop_caches: %d\n",
63 current->comm, task_pid_nr(current),
66 stfu |= sysctl_drop_caches & 4;