On 04/07/2020 20:32, Luc Van Oostenryck wrote: > On Sat, Jul 04, 2020 at 06:44:53PM +0100, Ramsay Jones wrote: >> On 04/07/2020 14:57, Luc Van Oostenryck wrote: >>> The 'Z' asm constraint is used for doing IO accessors on PPC but >>> isn't part of the 'common constraints'. It's responsible for >>> more than half of all warnings (with defconfig + allyesconfig). >> >> Not a problem, but this made me think 'half of which warnings'. :-D >> I assume, but it's just a guess, this means 'half of all asm-constraints >> warnings on the kernel PPC build'. >> >> How many warnings is that? What percentage is that of _all_ sparse >> warnings on a typical kernel build? > > It's literally more than half of all warnings issued by sparse when doing > a build of the kernel with 'defconfig' and another one with 'allyesconfig' > (all my tests on kernel builds are done like so) on a ppc64 machine: > $ grep ': \(error\|warning\):' log-master-master | wc -l > 138581 > $ grep ': \(error\|warning\):' log-arch-asm-mem | wc -l > 50006 > So, this series eliminates about 64% of all warnings, a nice > improvement of the S/N ratio. Oh, nice! It's a _long_ time since I last built the kernel (about when reading Greg's 'Linux Kernel in a Nutshell' book, so about 2006), and I don't even recall if I ran sparse over it. (Hmm, did you have to specify a C parameter to make or something?). Anyway, that is still a very large number of error/warnings - has it always been that bad? >> [BTW, I also noticed the (long running) 'luc/options' branch, which >> looks like it could prove to be a nice cleanup - I've only read the >> commit messages, not the actual commits.] > > Yes, I think it's a nice cleanup because this code is quite messy but, > OTOH, moving around all this code break all its history (via 'git blame' > or 'git log -L') is is guaranteed to create really nasty conflicts with > anything touching the code for the options. This is really a downside. Yep, I know what you mean. However, I don't think you should shy away from clean-ups for too long - it will be counter-productive in the end. ATB, Ramsay Jones
