Tejun, Paolo, On Tue, 17 Sep 2019 at 23:32, Tejun Heo <tj@xxxxxxxxxx> wrote: > > Hello, > > On Tue, Sep 17, 2019 at 06:51:48PM +0200, Paolo Valente wrote: > > When bfq was merged into mainline, there were two I/O schedulers that > > implemented the proportional-share policy: bfq for blk-mq and cfq for > > legacy blk. bfq's interface files in the blkio/io controller have the > > same names as cfq. But the cgroups interface doesn't allow two > > entities to use the same name for their files, so for bfq we had to > > prepend the "bfq" prefix to each of its files. However no legacy code > > uses these modified file names. This naming also causes confusion, as, > > e.g., in [1]. > > > > Now cfq has gone with legacy blk, so there is no need any longer for > > these prefixes in (the never used) bfq names. In view of this fact, this > > commit removes these prefixes, thereby enabling legacy code to truly > > use the proportional share policy in blk-mq. > > So, I wrote the iocost switching patch and don't have a strong > interest in whether bfq prefix should get dropped or not. However, I > gotta point out that flipping interface this way is way out of the > norm. > > In the previous release cycle, the right thing to do was dropping the > bfq prefix but that wasn't possible because bfq's interface wasn't > compatible at that point and didn't made to be compatible in time. Sounds like we really should send those relevant patches for stable, to set the correct ground. Then using a symlink, to make sure we don't brake current ABI, right? [...] Kind regards Uffe
