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| author | Theodore Ts'o <tytso@mit.edu> | 2006-09-27 01:50:46 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-09-27 08:26:17 -0700 |
| commit | 8e18e2941c53416aa219708e7dcad21fb4bd6794 (patch) | |
| tree | 44118f8b09556193ac93e0b71aecfa3e1d4bc182 /fs/debugfs | |
| parent | 6a1d9805ec506d8b9d04450997707da5f643d87c (diff) | |
| download | lwn-8e18e2941c53416aa219708e7dcad21fb4bd6794.tar.gz lwn-8e18e2941c53416aa219708e7dcad21fb4bd6794.zip | |
[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: "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>
Diffstat (limited to 'fs/debugfs')
| -rw-r--r-- | fs/debugfs/file.c | 4 | ||||
| -rw-r--r-- | fs/debugfs/inode.c | 4 |
2 files changed, 4 insertions, 4 deletions
diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c index e4b430552c88..bf3901ab1744 100644 --- a/fs/debugfs/file.c +++ b/fs/debugfs/file.c @@ -32,8 +32,8 @@ static ssize_t default_write_file(struct file *file, const char __user *buf, static int default_open(struct inode *inode, struct file *file) { - if (inode->u.generic_ip) - file->private_data = inode->u.generic_ip; + if (inode->i_private) + file->private_data = inode->i_private; return 0; } diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c index 3ca268d2e5a2..717f4821ed02 100644 --- a/fs/debugfs/inode.c +++ b/fs/debugfs/inode.c @@ -168,7 +168,7 @@ static int debugfs_create_by_name(const char *name, mode_t mode, * directory dentry if set. If this paramater is NULL, then the * file will be created in the root of the debugfs filesystem. * @data: a pointer to something that the caller will want to get to later - * on. The inode.u.generic_ip pointer will point to this value on + * on. The inode.i_private pointer will point to this value on * the open() call. * @fops: a pointer to a struct file_operations that should be used for * this file. @@ -209,7 +209,7 @@ struct dentry *debugfs_create_file(const char *name, mode_t mode, if (dentry->d_inode) { if (data) - dentry->d_inode->u.generic_ip = data; + dentry->d_inode->i_private = data; if (fops) dentry->d_inode->i_fop = fops; } |