On Tue, May 13, 2025 at 05:32:13PM +0800, Yu Kuai wrote: > I was thinking about record a stack dev depth in mddev to handle the > weird case inside raid. Is there other stack device have the same > problem? AFAIK, some dm targets like dm-crypt are using workqueue > to handle all IO.
I guess anything that might have to read in metadata to serve a data I/O. bcache, dm-snapshot and dm-thinkp would be candidates for that, but I haven't checked the implementation. > I'm still interested because this can improve first write latency. > >> >> So instead just write a comment documenting why you switch to a >> different stack using the workqueue. > > Ok, I'll add comment if we keep using the workqueue. Maybe do that for getting the new bitmap code in ASAP and then revisit the above separately?
