On Wed, 12 Apr 2023 18:27:08 +0100 Catalin Marinas <catalin.marinas@xxxxxxx> wrote: > > It sounds nice in theory. In practice. EXPERT hides too much. When you > > flip expert, you expose over a 175ish new config options which are > > hidden behind EXPERT. You don't have to know what you are doing just > > with the MAX_ORDER, but a whole bunch more as well. If everyone were > > already running 10, this might be less of a problem. At least Fedora > > and RHEL are running 13 for 4K pages on aarch64. This was not some > > accidental choice, we had to carry a patch to even allow it for a > > while. If this does go in as is, we will likely just carry a patch to > > remove the "if EXPERT", but that is a bit of a disservice to users who > > might be trying to debug something else upstream, bisecting upstream > > kernels or testing a patch. In those cases, people tend to use > > pristine upstream sources without distro patches to verify, and they > > tend to use their existing configs. With this change, their MAX_ORDER > > will drop to 10 from 13 silently. That can look like a different > > issue enough to ruin a bisect or have them give bad feedback on a > > patch because it introduces a "regression" which is not a regression > > at all, but a config change they couldn't see. > > If we remove EXPERT (as prior to this patch), I'd rather keep the ranges > and avoid having to explain to people why some random MAX_ORDER doesn't > build (keeping the range would also make sense for randconfig, not sure > we got to any conclusion there). Well this doesn't seem to have got anywhere. I think I'll send the patchset into Linus for the next merge window as-is. Please let's take a look at this Kconfig presentation issue during the following -rc cycle.
