On 02/22/2017 11:56 AM, Linus Torvalds wrote: > On Wed, Feb 22, 2017 at 10:52 AM, Jens Axboe <axboe@xxxxxxxxx> wrote: >>> >>> It's that simple. >> >> No, it's not that simple at all. Fact is, some optimizations make sense >> for some workloads, and some do not. > > Are you even listening? > > I'm saying no user can ever give a sane answer to your question. The > question is insane and wrong. > > I already said you can have a dynamic configuration (and maybe even an > automatic heuristic - like saying that a ramdisk gets NOOP by default, > real hardware does not). > > But asking a user at kernel config time for a default is insane. If > *you* cannot answer it, then the user sure as hell cannot. > > Other configuration questions have problems too, but at least the > question about "should I support ext4" is something a user (or distro) > can sanely answer. So your comparisons are pure bullshit. As per the previous email, this was my proposed solution: OK, so here's what I'll do: 1) We'll kill the default scheduler choices. sq blk-mq will default to mq-deadline, mq blk-mq will default to "none" (at least for now, until the new scheduler is done). 2) The individual schedulers will be y/m/n selectable, just like any other driver. Any further settings on that can be done at runtime, through sysfs. -- Jens Axboe
