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Viewing changes to fs/drop_caches.c

  • Committer: Package Import Robot
  • Author(s): Alessio Igor Bogani
  • Date: 2011-10-26 11:13:05 UTC
  • Revision ID: package-import@ubuntu.com-20111026111305-tz023xykf0i6eosh
Tags: upstream-3.2.0
Import upstream version 3.2.0

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fs/drop_caches.c
 
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/*
 
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 * Implement the manual drop-all-pagecache function
 
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 */
 
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#include <linux/kernel.h>
 
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#include <linux/mm.h>
 
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#include <linux/fs.h>
 
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#include <linux/writeback.h>
 
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#include <linux/sysctl.h>
 
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#include <linux/gfp.h>
 
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#include "internal.h"
 
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/* A global variable is a bit ugly, but it keeps the code simple */
 
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int sysctl_drop_caches;
 
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static void drop_pagecache_sb(struct super_block *sb, void *unused)
 
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{
 
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        struct inode *inode, *toput_inode = NULL;
 
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        spin_lock(&inode_sb_list_lock);
 
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        list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
 
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                spin_lock(&inode->i_lock);
 
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                if ((inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW)) ||
 
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                    (inode->i_mapping->nrpages == 0)) {
 
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                        spin_unlock(&inode->i_lock);
 
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                        continue;
 
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                }
 
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                __iget(inode);
 
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                spin_unlock(&inode->i_lock);
 
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                spin_unlock(&inode_sb_list_lock);
 
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                invalidate_mapping_pages(inode->i_mapping, 0, -1);
 
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                iput(toput_inode);
 
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                toput_inode = inode;
 
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                spin_lock(&inode_sb_list_lock);
 
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        }
 
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        spin_unlock(&inode_sb_list_lock);
 
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        iput(toput_inode);
 
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}
 
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static void drop_slab(void)
 
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{
 
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        int nr_objects;
 
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        struct shrink_control shrink = {
 
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                .gfp_mask = GFP_KERNEL,
 
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        };
 
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        do {
 
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                nr_objects = shrink_slab(&shrink, 1000, 1000);
 
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        } while (nr_objects > 10);
 
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}
 
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int drop_caches_sysctl_handler(ctl_table *table, int write,
 
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        void __user *buffer, size_t *length, loff_t *ppos)
 
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{
 
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        int ret;
 
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        ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
 
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        if (ret)
 
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                return ret;
 
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        if (write) {
 
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                if (sysctl_drop_caches & 1)
 
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                        iterate_supers(drop_pagecache_sb, NULL);
 
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                if (sysctl_drop_caches & 2)
 
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                        drop_slab();
 
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        }
 
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        return 0;
 
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}