Re: [PATCH RFC DRAFT DOESNOTBUILD] inode: free up more space

Darrick J. Wong
2025-07-17T15:55:57Z

On Thu, Jul 17, 2025 at 09:51:23AM +0200, Christoph Hellwig wrote:
> On Thu, Jul 17, 2025 at 09:48:49AM +0200, Christian Brauner wrote:
> > On Wed, Jul 16, 2025 at 03:02:00PM +0200, Christoph Hellwig wrote:
> > > On Tue, Jul 15, 2025 at 05:09:03PM +0100, Matthew Wilcox wrote:
> > > > will be harder, we have to get to 604 bytes. Although for my system if
> > > > we could get xfs_inode down from 1024 bytes to 992, that'd save me much
> > > > more memory ;-)
> > >
> > > There's some relatively low hanging fruit there.
> > >
> > > One would be to make the VFS inode i_ino a u64 finally so that XFS
> > > and other modern files systems an stop having their own duplicate of
> >
> > That's already on my TODO since we discussed this with Jeff last year.
>
> Cool!
>
> Btw, I remember anothing I've been wanting to look at, which is
> killing the u/g/p quota pointers. If we used a rhashtable with
> proper sizing for them, doing a hash lookup instead of the caching
> should be efficient enough to be noise compared to the actual quota
> operations. That would free three pointers per inode, or in case
> of XFS six without the optimization in this thread.

That would be really nice. :)

--D