On Fri, Oct 11, 2024 at 02:21:02PM +0200, Javier Gonzalez wrote: > > That's a lot of marketing babble :) What exact thing is missing > > from the passthrough interface when using say spdx over io_uring? > > The block layer provides a lot of functionality that passthru cannot > provide. A simple example would be splits. You know this :) > > I am sure Jens and Keith can give you more specifics on their particular > reasons. Splitting, merging, cgroups, iostats, error retries, failover. We have a recent change staged in 6.13 to try to count iostats on passthrough, but it doesn't do discards. Passthrough to partitions requires root access and the slow CAP_SYSADMIN check on every IO. Page cache. Though that may not readily work with this io_uring proposal as-is either. The generic IO path is safe to changing formats; passthrough isn't. And it's just generally more work to port existing applications to use the passthrough interface. It causes duplicating solutions to scenarios the kernel already handles.
