linux/fs/drop_caches.c
Mike Waychison 286973552f mm: remove __invalidate_mapping_pages variant
Remove __invalidate_mapping_pages atomic variant now that its sole caller
can sleep (fixed in eccb95cee4 ("vfs: fix
lock inversion in drop_pagecache_sb()")).

This fixes softlockups that can occur while in the drop_caches path.

Signed-off-by: Mike Waychison <mikew@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-16 19:47:43 -07:00

76 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_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,
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;
}