[reiserfs-list] Re: [OpenAFS-devel] more on the 2.2.18pre17 SMPcpu hog/etc.

Andi Kleen ak@suse.de
Tue, 5 Dec 2000 01:24:15 +0100

On Mon, Dec 04, 2000 at 07:00:54PM -0500, Jeffrey Hutzelman wrote:
> > Actually with the efficient dcache in 2.2+ I suspect that method could
> > be used unconditionally on Linux for all file systems without much if
> > any slowdown.  As long as the dentries stay cached there is no directory
> > walking overhead even on filesystem with not-so-well scaling directories
> > like ext2. 
> But I don't think you want to keep 32K+ dentries all the time, or assume
> that they will stay in the cache.

I was not aware that it needs that many files.

Ok, then normal iget() for ext2 and file names for reiserfs and XFS or people
who want to use multiple file systems for their cache (if you can spare a few
bits in the pseudo inode to index into a path name table). The user could
switch it with an option. 

> > copied inode structure looks very fragile and has e.g. caused problems
> > with the suse kernel (which has two fields more than a normal linux 2.2
> > inode)
> It's not as fragile as you might think.  The inode structure doesn't
> change all that frequently, and using symbol versions catches it when
> it does change.  Unfortunately, far too many people use AFS modules
> without symbol versions.  I'm hoping that will begin to change.

I know that it breaks here.