a4ffdde6e5
add I_CLEAR instead of replacing I_FREEING with it. I_CLEAR is equivalent to I_FREEING for almost all code looking at either; it's there to keep track of having called clear_inode() exactly once per inode lifetime, at some point after having set I_FREEING. I_CLEAR and I_FREEING never get set at the same time with the current code, so we can switch to setting i_flags to I_FREEING | I_CLEAR instead of I_CLEAR without loss of information. As the result of such change, checks become simpler and the amount of code that needs to know about I_CLEAR shrinks a lot. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
57 lines
1.3 KiB
C
57 lines
1.3 KiB
C
/*
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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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/* 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_lock);
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list_for_each_entry(inode, &sb->s_inodes, i_sb_list) {
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if (inode->i_state & (I_FREEING|I_WILL_FREE|I_NEW))
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continue;
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if (inode->i_mapping->nrpages == 0)
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continue;
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__iget(inode);
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spin_unlock(&inode_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_lock);
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}
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spin_unlock(&inode_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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do {
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nr_objects = shrink_slab(1000, GFP_KERNEL, 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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proc_dointvec_minmax(table, write, buffer, length, ppos);
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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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}
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