On Fri, Mar 16, 2018 at 1:56 PM, Kirill A. Shutemov <kirill@xxxxxxxxxxxxx> wrote: > > Increase of readahead window was proposed several times. And rejected. > IIRC, Linus was against it. I have never seen any valid situation that wasn't tuning for one odd machine, usually with a horribly crappy disk setup and very little testing of latencies or low-memory situations. And "horribly crappy" very much tends to include "big serious enterprise hardware" that people paid big bucks for, and that has huge theoretical throughput for large transfers, but is pure garbage in every other way. So I'm still very much inclined against these kinds of things. They need *extensive* numbers and explanations for why it's not just some uncommon thing for one setup. Linus