On Tue, Jan 03, 2023 at 11:53:37AM -0800, Bart Van Assche wrote: > Remove the code for fair tag sharing because it significantly hurts > performance for UFS devices. Removing this code is safe because the > legacy block layer worked fine without any equivalent fairness > algorithm. The legacy block layer didn't have a limited tag resource that can block request allocations though, so I don't think we can appeal to that example to conclude removing this is safe. As much as I'd like to get rid of this code, I honestly have no idea if this isn't helping anyone. > This algorithm hurts performance for UFS devices because UFS devices > have multiple logical units. One of these logical units (WLUN) is used > to submit control commands, e.g. START STOP UNIT. If any request is > submitted to the WLUN, the queue depth is reduced from 31 to 15 or > lower for data LUNs. Can you give the WLUN it's own tagset instead?
