On Fri, Jul 03, 2020 at 07:00:11AM -0700, Doug Anderson wrote: > Hi, > > On Fri, Jul 3, 2020 at 4:40 AM Mike Rapoport <rppt@xxxxxxxxxxxxx> wrote: > > > > On Thu, Jul 02, 2020 at 11:43:47PM -0700, Abhishek Bhardwaj wrote: > > > We have tried to steer away from kernel command line args for a few reasons. > > > > > > I am paraphrasing my colleague Doug's argument here (CC'ed him as well) - > > > > > > - The command line args are getting unwieldy. Kernel command line > > > parameters are not a scalable way to set kernel config. It's intended > > > as a super limited way for the bootloader to pass info to the kernel > > > and also as a way for end users who are not compiling the kernel > > > themselves to tweak kernel behavior. > > > > Why cannot you simply add this option to CONFIG_CMDLINE at your kernel build > > scripts? > > At least in the past I've seen that 'CONFIG_CMDLINE' interacts badly > with the bootloader provided command line in some architectures. In > days of yore I tried to post a patch to fix this, at least on ARM > targets, but it never seemed to go anywhere upstream. I'm going to > assume this is still a problem because I still see an ANDROID tagged > patch in the Chrome OS 5.4 tree: I presume a patch subject should have been here :) Anyway, bad iteraction of CONFIG_CMDLINE with bootloader command line seems like a bug to me and a bug need to be fixed. > In any case, as per my previous arguments, stuffing lots of config > into the cmdline is a bit clunky and doesn't scale well. You end up > with a really long run on command line and it's hard to tell where one > config option ends and the next one starts and if the same concept is > there more than one time it's hard to tell and something might cancel > out a previous config option or maybe it won't and by the time you end > up finishing this it's hard to tell where you started. :-) Configuration options may also have weird interactions between them and addition of #ifdef means that most of the non-default paths won't get as good test coverage as the default one. And the proposed #ifdef maze does not look pretty at all... > > > - Also, we know we want this setting from the start. This is a > > > definite smell that it deserves to be a compile time thing rather than > > > adding extra code + whatever miniscule time at runtime to pass an > > > extra arg. > > > > This might be a compile time thing in your environment, but not > > necessarily it must be the same in others. For instance, what option > > should distro kernels select? > > Nothing prevents people from continuing to use the command line > options if they want, right? This just allows a different default. > So if a distro is security focused and decided that it wanted a slower > / more secure default then it could ship that way but individual users > could still override, right? Well, nothing prevents you from continuing to use the command line as well ;-) I can see why whould you want an ability to select compile time default for an option, but I'm really not thrilled by the added ifdefery. > > > I think this was what CONFIGS were intended for. I'm happy to add all > > > this to the commit message once it's approved in spirit by the > > > maintainers. > > > -- Sincerely yours, Mike.
