On Thu, Jul 5, 2018 at 7:40 PM Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> wrote: > > > > > No, direct reclaim is a way to throttle allocations to the reclaim > > speed. You would have to achive the same by other means. > > No. Direct reclaim is a way to lockup the system to unusable level, by not giving > enough CPU resources to memory reclaim activities including the owner of oom_lock. No. Really. Direct reclaim really really does what Michal claims. Yes, it has other effects too, and it can be problematic, but direct reclaim is important. People have tried to remove it many times, but it's always been a disaster. You need to synchronize with _something_ to make sure that the thread that is causing a lot of allocations actually pays the price, and slows down. You want to have a balance between direct and indirect reclaim. If you think direct reclaim is only a way to lock up the system to unusable levels, you should stop doing VM development. Linus