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git.proxmox.com Git - mirror_ubuntu-kernels.git/blob - fs/drop_caches.c
1 // SPDX-License-Identifier: GPL-2.0
3 * Implement the manual drop-all-pagecache function
6 #include <linux/pagemap.h>
7 #include <linux/kernel.h>
10 #include <linux/writeback.h>
11 #include <linux/sysctl.h>
12 #include <linux/gfp.h>
15 /* A global variable is a bit ugly, but it keeps the code simple */
16 int sysctl_drop_caches
;
18 static void drop_pagecache_sb(struct super_block
*sb
, void *unused
)
20 struct inode
*inode
, *toput_inode
= NULL
;
22 spin_lock(&sb
->s_inode_list_lock
);
23 list_for_each_entry(inode
, &sb
->s_inodes
, i_sb_list
) {
24 spin_lock(&inode
->i_lock
);
26 * We must skip inodes in unusual state. We may also skip
27 * inodes without pages but we deliberately won't in case
28 * we need to reschedule to avoid softlockups.
30 if ((inode
->i_state
& (I_FREEING
|I_WILL_FREE
|I_NEW
)) ||
31 (mapping_empty(inode
->i_mapping
) && !need_resched())) {
32 spin_unlock(&inode
->i_lock
);
36 spin_unlock(&inode
->i_lock
);
37 spin_unlock(&sb
->s_inode_list_lock
);
39 invalidate_mapping_pages(inode
->i_mapping
, 0, -1);
44 spin_lock(&sb
->s_inode_list_lock
);
46 spin_unlock(&sb
->s_inode_list_lock
);
50 int drop_caches_sysctl_handler(struct ctl_table
*table
, int write
,
51 void *buffer
, size_t *length
, loff_t
*ppos
)
55 ret
= proc_dointvec_minmax(table
, write
, buffer
, length
, ppos
);
61 if (sysctl_drop_caches
& 1) {
62 iterate_supers(drop_pagecache_sb
, NULL
);
63 count_vm_event(DROP_PAGECACHE
);
65 if (sysctl_drop_caches
& 2) {
67 count_vm_event(DROP_SLAB
);
70 pr_info("%s (%d): drop_caches: %d\n",
71 current
->comm
, task_pid_nr(current
),
74 stfu
|= sysctl_drop_caches
& 4;