On Thu 15-08-19 14:51:04, Khalid Aziz wrote: > Hi Michal, > > The smarts for tuning these knobs can be implemented in userspace and > more knobs added to allow for what is missing today, but we get back to > the same issue as before. That does nothing to make kernel self-tuning > and adds possibly even more knobs to userspace. Something so fundamental > to kernel memory management as making free pages available when they are > needed really should be taken care of in the kernel itself. Moving it to > userspace just means the kernel is hobbled unless one installs and tunes > a userspace package correctly. >From my past experience the existing autotunig works mostly ok for a vast variety of workloads. A more clever tuning is possible and people are doing that already. Especially for cases when the machine is heavily overcommited. There are different ways to achieve that. Your new in-kernel auto tuning would have to be tested on a large variety of workloads to be proven and riskless. So I am quite skeptical to be honest. Therefore I would really focus on discussing whether we have sufficient APIs to tune the kernel to do the right thing when needed. That requires to identify gaps in that area. -- Michal Hocko SUSE Labs
