Hello, Paolo. On Tue, Dec 18, 2018 at 08:48:10AM +0100, Paolo Valente wrote: > If Tejun cannot see any solution to his concern, then can we just > switch to this extension, considering that > - for non-shared names the interface is *identical* to the current > one; > - by using this new interface, and getting feedback we could > understand how to better handle Tejun's concern? > A lot of systems do use weights, and people don't even know that these > systems don't work correctly in blk-mq. And they won't work correctly > in any available configuration from 4.21, if we don't fix this problem. So, when seen from userland, how it should behave isn't vague or complicated. For a given device and policy type, there can be only one implementation active. It doesn't make sense to have two weight mechanisms active on one device, right? So, the interface should only present what makes sense to the user for both configuration knobs and statistics, and that'd be a hard requirement because we don't want to present confusing spurious information to userspace. There seemd to have been significant misunderstandings as to what the requirements are when this was discussed way back, so idk what the good path forward is at this point. Just keep the current names? Thanks. -- tejun
