On Thu, Jun 12, 2025 at 09:21:35AM -0400, Chuck Lever wrote: > On 6/11/25 3:18 PM, Mike Snitzer wrote: > > On Wed, Jun 11, 2025 at 10:31:20AM -0400, Chuck Lever wrote: > >> On 6/10/25 4:57 PM, Mike Snitzer wrote: > >>> Add 'enable-dontcache' to NFSD's debugfs interface so that: Any data > >>> read or written by NFSD will either not be cached (thanks to O_DIRECT) > >>> or will be removed from the page cache upon completion (DONTCACHE). > >> > >> I thought we were going to do two switches: One for reads and one for > >> writes? I could be misremembering. > > > > We did discuss the possibility of doing that. Still can-do if that's > > what you'd prefer. > > For our experimental interface, I think having read and write enablement > as separate settings is wise, so please do that. > > One quibble, though: The name "enable_dontcache" might be directly > meaningful to you, but I think others might find "enable_dont" to be > oxymoronic. And, it ties the setting to a specific kernel technology: > RWF_DONTCACHE. > > So: Can we call these settings "io_cache_read" and "io_cache_write" ? > > They could each carry multiple settings: > > 0: Use page cache > 1: Use RWF_DONTCACHE > 2: Use O_DIRECT > > You can choose to implement any or all of the above three mechanisms. I like it, will do for v2. But will have O_DIRECT=1 and RWF_DONTCACHE=2. Thanks, Mike
