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[PATCH] inode_diet: Replace inode.u.generic_ip with inode.i_private

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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: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Judith Lebzelter <judith@osdl.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Theodore Ts'o
2006-09-27 01:50:46 -07:00
committed by Linus Torvalds
parent 6a1d9805ec
commit 8e18e2941c
36 changed files with 88 additions and 90 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
arch/powerpc/platforms/cell/spufs/inode.c
View File

@@ -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;

2
arch/powerpc/platforms/pseries/hvCall_inst.c
View File

@@ -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;
}

6
arch/s390/hypfs/inode.c
View File

@@ -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;

2
arch/s390/kernel/debug.c
View File

@@ -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])