On Tue, Jul 9, 2024, at 17:27, Jeff Layton wrote: > On Tue, 2024-07-09 at 17:07 +0200, Arnd Bergmann wrote: >> On Tue, Jul 9, 2024, at 16:23, Jeff Layton wrote: > > The context for this is generally a write or other change to an inode, > so I too am hoping the overhead won't be too bad. It does take great > pains to avoid changing the ctime_floor value whenever possible. Ok, I see. Have you considered hooking directly into the code in kernel/time/timekeeping.c then? Since the coarse time is backed by the timekeeper that itself is a cache of the current time, this would potentially avoid some duplication: - whenever the tk_core code gets updated, you can update the ctime_floor along with it, or integrate ctime_floor itself into the timekeeper - you can use the same sequence count logic, either with the same &tk_core.seq or using a separate counter for the ctime updates Arnd