[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>
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committed by
Linus Torvalds

parent
6a1d9805ec
commit
8e18e2941c
@@ -177,7 +177,7 @@ int devpts_pty_new(struct tty_struct *tty)
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inode->i_gid = config.setgid ? config.gid : current->fsgid;
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inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
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init_special_inode(inode, S_IFCHR|config.mode, device);
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inode->u.generic_ip = tty;
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inode->i_private = tty;
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dentry = get_node(number);
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if (!IS_ERR(dentry) && !dentry->d_inode)
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@@ -196,7 +196,7 @@ struct tty_struct *devpts_get_tty(int number)
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tty = NULL;
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if (!IS_ERR(dentry)) {
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if (dentry->d_inode)
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tty = dentry->d_inode->u.generic_ip;
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tty = dentry->d_inode->i_private;
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dput(dentry);
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}
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