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Commit 8e18e294 authored by Theodore Ts'o's avatar Theodore Ts'o Committed by Linus Torvalds
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[PATCH] inode_diet: Replace inode.u.generic_ip with inode.i_private 



The following patches reduce the size of the VFS inode structure by 28 bytes
on a UP x86.  (It would be more on an x86_64 system).  This is a 10% reduction
in the inode size on a UP kernel that is configured in a production mode
(i.e., with no spinlock or other debugging functions enabled; if you want to
save memory taken up by in-core inodes, the first thing you should do is
disable the debugging options; they are responsible for a huge amount of bloat
in the VFS inode structure).

This patch:

The filesystem or device-specific pointer in the inode is inside a union,
which is pretty pointless given that all 30+ users of this field have been
using the void pointer.  Get rid of the union and rename it to i_private, with
a comment to explain who is allowed to use the void pointer.  This is just a
cleanup, but it allows us to reuse the union 'u' for something something where
the union will actually be used.

[judith@osdl.org: powerpc build fix]
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: default avatarJudith Lebzelter <judith@osdl.org>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 6a1d9805

arch/powerpc/platforms/cell/spufs/inode.c

+1 −1
Original line number Diff line number Diff line
@@ -120,7 +120,7 @@ spufs_new_file(struct super_block *sb, struct dentry *dentry, 
	ret = 0;

	inode->i_op = &spufs_file_iops;

	inode->i_fop = fops;

	inode->u.generic_ip = SPUFS_I(inode)->i_ctx = get_spu_context(ctx);

	inode->i_private = SPUFS_I(inode)->i_ctx = get_spu_context(ctx);

	d_add(dentry, inode);

out:

	return ret;

arch/powerpc/platforms/pseries/hvCall_inst.c

+1 −1
Original line number Diff line number Diff line
@@ -85,7 +85,7 @@ static int hcall_inst_seq_open(struct inode *inode, struct file *file) 


	rc = seq_open(file, &hcall_inst_seq_ops);

	seq = file->private_data;

	seq->private = file->f_dentry->d_inode->u.generic_ip;

	seq->private = file->f_dentry->d_inode->i_private;



	return rc;

}

arch/s390/hypfs/inode.c

+3 −3
Original line number Diff line number Diff line
@@ -104,13 +104,13 @@ static struct inode *hypfs_make_inode(struct super_block *sb, int mode) 


static void hypfs_drop_inode(struct inode *inode)

{

	kfree(inode->u.generic_ip);

	kfree(inode->i_private);

	generic_delete_inode(inode);

}



static int hypfs_open(struct inode *inode, struct file *filp)

{

	char *data = filp->f_dentry->d_inode->u.generic_ip;

	char *data = filp->f_dentry->d_inode->i_private;

	struct hypfs_sb_info *fs_info;



	if (filp->f_mode & FMODE_WRITE) {
@@ -352,7 +352,7 @@ static struct dentry *hypfs_create_file(struct super_block *sb, 
		parent->d_inode->i_nlink++;

	} else

		BUG();

	inode->u.generic_ip = data;

	inode->i_private = data;

	d_instantiate(dentry, inode);

	dget(dentry);

	return dentry;

arch/s390/kernel/debug.c

+1 −1
Original line number Diff line number Diff line
@@ -603,7 +603,7 @@ debug_open(struct inode *inode, struct file *file) 
	debug_info_t *debug_info, *debug_info_snapshot;



	down(&debug_lock);

	debug_info = (struct debug_info*)file->f_dentry->d_inode->u.generic_ip;

	debug_info = file->f_dentry->d_inode->i_private;

	/* find debug view */

	for (i = 0; i < DEBUG_MAX_VIEWS; i++) {

		if (!debug_info->views[i])

block/blktrace.c

+1 −1
Original line number Diff line number Diff line
@@ -217,7 +217,7 @@ static int blk_trace_remove(request_queue_t *q) 


static int blk_dropped_open(struct inode *inode, struct file *filp)

{

	filp->private_data = inode->u.generic_ip;

	filp->private_data = inode->i_private;



	return 0;

}