Re: [RFC PATCH 0/8] xfs: shrink the struct xfs_icdinode

Christoph Hellwig
2016-01-12T15:30:16Z

Nice!

I had started on some of this a while ago but never finished it..

> 72 bytes. This means it takes 104 bytes off the size of the struct
> xfs_inode, which a 12% reduction in size. This will be a massive win
> for systems that cache lots of inodes!

How many more inodes can we fit into a slab cache now? Back when I
started I noticed it doesn't help us to actually fit more inodes into
a 4k page due to the bloated VFS inode. But these days slub actually
uses a high order allocations if I remember correctly so it might be
more useful.

> With this change made, the xfs_icdinode is no long an "in core disk
> inode" so I'm wondering whether I should rename it or simply make it
> go away altogether and pull the remaining fields straight into the
> struct xfs_inode. Any thoughts on new names and/or getting rid of it
> woul dbe appreciated.

I think it should be merged into the xfs_inode structure soner or
later. Another thign I planned but never got to is to move fields
into the inode fork that were specific to the attr or data fork.