Re: [PATCH 01/10] fs: turn inode ctime fields into a single ktime_t

Christoph Hellwig
2024-07-03T05:27:03Z

On Tue, Jul 02, 2024 at 11:58:02AM -0400, Jeff Layton wrote:
> Yeah, mostly. We shrink struct inode by 8 bytes with that patch, and we
> (probably) get a better cache footprint, since i_version ends up in the
> same cacheline as the ctime. That's really a separate issue though, so
> I'm not too worked up about dropping that patch.
>
> As a bonus, leaving it split across separate fields means that we can
> use unused bits in the nsec field for the flag, so we don't need to
> sacrifice any timestamp granularity either.
>
> I've got a draft rework that does this that I'm testing now. Assuming
> it works OK, I'll resend in a few days.

So while shrinking the inodes sounds nice, the tradeoff to have to
check all timestamps from disk / the server for validity doesn't
sound as positive. So I'm glade we're avoiding this at least for.