On Thu, Feb 02, 2023 at 12:13:02PM -0800, Sukadev Bhattiprolu wrote: > > Hi Roman, > > On Wed, Feb 01, 2023 at 11:00:25AM -0800, Roman Gushchin wrote: > > Then _maybe_ a new knob is justified, at least I don't have better ideas. > > Rik, do you have any input here? > > > > Let's then define it in a more generic way and _maybe_ move to the cma > > sysfs/debugfs (not 100% sure about this part, but probably worth exploring). > > We should be able to use a sysfs parameter too. Will try that out. Thanks. The reason I think it might be preferable is that new sysctls are hated by everyone and this use case looks a very niche. > But could you elaborate on what is more generic way? I mean in the proposed patch it's only possible to shift the ratio towards cma: a larger sysctl value will make allocations from the cma area happening earlier. The value 1 will turn it off completely. Probably better to define the new knob in % or 1/1000's with the default value 50% or 500. 0 will mean never use cma from this path, 999 - always. Something along these lines. Thanks!
