[linux-block.git] / fs / drop_caches.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_CLEAR|I_WILL_FREE|I_NEW))
			continue;
		if (inode->i_mapping->nrpages == 0)
			continue;
		__iget(inode);
		spin_unlock(&inode_lock);
		invalidate_mapping_pages(inode->i_mapping, 0, -1);
		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,
	void __user *buffer, size_t *length, loff_t *ppos)
{
	proc_dointvec_minmax(table, write, buffer, length, ppos);
	if (write) {
		if (sysctl_drop_caches & 1)
			drop_pagecache();
		if (sysctl_drop_caches & 2)
			drop_slab();
	}
	return 0;
}
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) {
b6fac63c	21	if (inode->i_state & (I_FREEING\|I_CLEAR\|I_WILL_FREE\|I_NEW))
9d0243bc	22	continue;
af065b8a JK	23	if (inode->i_mapping->nrpages == 0)
af065b8a JK	24	continue;
eccb95ce JK	25	__iget(inode);
eccb95ce JK	26	spin_unlock(&inode_lock);
28697355	27	invalidate_mapping_pages(inode->i_mapping, 0, -1);
eccb95ce JK	28	iput(toput_inode);
	29	toput_inode = inode;
	30	spin_lock(&inode_lock);
9d0243bc AM	31	}
9d0243bc AM	32	spin_unlock(&inode_lock);
eccb95ce	33	iput(toput_inode);
9d0243bc AM	34	}
9d0243bc AM	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,
8d65af78	66	void __user buffer, size_t length, loff_t *ppos)
9d0243bc	67	{
8d65af78	68	proc_dointvec_minmax(table, write, buffer, length, ppos);
9d0243bc AM	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	}