On 7/11/23 6:53 PM, Dominique Martinet wrote: > Jens Axboe wrote on Tue, Jul 11, 2023 at 05:51:46PM -0600: >>> So what filesystem actually uses this new NOWAIT functionality? >>> Unless I'm blind (quite possibly) I don't see any filesystem >>> implementation of this functionality in the patch series. > > I had implemented this for kernfs and libfs (so sysfs, debugfs, possibly > tmpfs/proc?) in v2 > > The patch as of v2's mail has a bug, but my branch has it fixed as of > https://github.com/martinetd/linux/commits/io_uring_getdents > > (I guess these aren't "real" enough though) No, I definitely think those are real and valid. But would be nice with a "real" file system as well. >>> I know I posted a prototype for XFS to use it, and I expected that >>> it would become part of this patch series to avoid the "we don't add >>> unused code to the kernel" problem. i.e. the authors would take the >>> XFS prototype, make it work, add support into for the new io_uring >>> operation to fsstress in fstests and then use that to stress test >>> the new infrastructure before it gets merged.... >>> >>> But I don't see any of this? >> >> That would indeed be great if we could get NOWAIT, that might finally >> convince me that it's worth plumbing up! Do you have a link to that >> prototype? That seems like what should be the base for this, and be an >> inspiration for other file systems to get efficient getdents via this >> (rather than io-wq punt, which I'm not a huge fan of...). > > the xfs poc was in this mail: > https://lore.kernel.org/all/20230501071603.GE2155823@xxxxxxxxxxxxxxxxxxx/ > > I never spent time debugging it, but it should definitely be workable If either you or Hao wants to take a stab at it and see how it goes, I think that would be hugely beneficial for this patchset. -- Jens Axboe
