Re: hundreds of mount --bind mountpoints?

Erik Mouw
2001-04-24T20:46:33Z

On Tue, Apr 24, 2001 at 12:47:38PM -0600, Andreas Dilger wrote:
> While I applaud your initiative, you made an unfortunate choice of
> filesystems to convert. The iso_inode_info is only 4*__u32, as is
> proc_inode_info. Given that we still need to keep a pointer to the
> external info structs, and the overhead of the slab cache itself
> (both CPU usage and memory overhead, however small), I don't think
> it is worthwhile to have isofs and procfs in separate slabs.

Well, I know a little bit about procfs because I'm currently
documenting it, so that's why I picked it first. After I got the idea,
isofs was quite easy.

In retrospect it would have been more effective to pick a filesystem
with a larger *_inode_info field, but then again: Al is right. Struct
inode is cluttered with *_inode_info fields, while we use anonymous
data entries in other parts of the kernel (like the data pointer in
struct proc_dir_entry, or the priv pointer in struct net_device).

There is another advantage: suppose you're hacking on a filesystem and
change it's *_fs_i.h header. With Al's proposal you only have to
recompile the filesystem you're hacking on, while you have to recompile
the complete kernel in the current situation.

Erik

--
J.A.K. (Erik) Mouw, Information and Communication Theory Group, Department
of Electrical Engineering, Faculty of Information Technology and Systems,
Delft University of Technology, PO BOX 5031, 2600 GA Delft, The Netherlands
Phone: +31-15-2783635 Fax: +31-15-2781843 Email: J.A.K.Mouw@its.tudelft.nl
WWW: http://www-ict.its.tudelft.nl/~erik/