77 lines
1.6 KiB
C
77 lines
1.6 KiB
C
/*
|
|
* Implement the manual drop-all-pagecache function
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/writeback.h>
|
|
#include <linux/sysctl.h>
|
|
#include <linux/gfp.h>
|
|
|
|
/* A global variable is a bit ugly, but it keeps the code simple */
|
|
int sysctl_drop_caches;
|
|
|
|
static void drop_pagecache_sb(struct super_block *sb)
|
|
{
|
|
struct inode *inode, *toput_inode = NULL;
|
|
|
|
spin_lock(&inode_lock);
|
|
list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
|
|
if (inode->i_state & (I_FREEING|I_WILL_FREE))
|
|
continue;
|
|
if (inode->i_mapping->nrpages == 0)
|
|
continue;
|
|
__iget(inode);
|
|
spin_unlock(&inode_lock);
|
|
__invalidate_mapping_pages(inode->i_mapping, 0, -1, true);
|
|
iput(toput_inode);
|
|
toput_inode = inode;
|
|
spin_lock(&inode_lock);
|
|
}
|
|
spin_unlock(&inode_lock);
|
|
iput(toput_inode);
|
|
}
|
|
|
|
static void drop_pagecache(void)
|
|
{
|
|
struct super_block *sb;
|
|
|
|
spin_lock(&sb_lock);
|
|
restart:
|
|
list_for_each_entry(sb, &super_blocks, s_list) {
|
|
sb->s_count++;
|
|
spin_unlock(&sb_lock);
|
|
down_read(&sb->s_umount);
|
|
if (sb->s_root)
|
|
drop_pagecache_sb(sb);
|
|
up_read(&sb->s_umount);
|
|
spin_lock(&sb_lock);
|
|
if (__put_super_and_need_restart(sb))
|
|
goto restart;
|
|
}
|
|
spin_unlock(&sb_lock);
|
|
}
|
|
|
|
static void drop_slab(void)
|
|
{
|
|
int nr_objects;
|
|
|
|
do {
|
|
nr_objects = shrink_slab(1000, GFP_KERNEL, 1000);
|
|
} while (nr_objects > 10);
|
|
}
|
|
|
|
int drop_caches_sysctl_handler(ctl_table *table, int write,
|
|
struct file *file, void __user *buffer, size_t *length, loff_t *ppos)
|
|
{
|
|
proc_dointvec_minmax(table, write, file, buffer, length, ppos);
|
|
if (write) {
|
|
if (sysctl_drop_caches & 1)
|
|
drop_pagecache();
|
|
if (sysctl_drop_caches & 2)
|
|
drop_slab();
|
|
}
|
|
return 0;
|
|
}
|