On Sat, Jul 27, 2024 at 09:26:43AM GMT, Linus Torvalds wrote: > On Sat, 27 Jul 2024 at 01:08, Lorenzo Stoakes > <lorenzo.stoakes@xxxxxxxxxx> wrote: > > > > 62603617./drivers/staging/media/atomisp/pci/isp/kernels/ynr/ynr_1.0/ia_css_ynr.host.o.pre > > Heh. > > Longest line is drivers/.../ia_css_ynr.host.c:71 (27785kB) > > yeah, that's a single line that expands to 27MB in size. > > And yes, that line is one single min(...) expression with arguments > that are then in turn macros with other nested min/max arguments. > > See also drivers/staging/media/atomisp/pci/sh_css_frac.h. > > On my fairly beefy (admittedly more cores than single-thread) machine, > just generating the preprocessor file takes just under 20s. > > Building the object file is actually faster at "only" 8.5s for that > one file, because it uses the built-in preprocessor and never writes > it out, and most of the actual preprocessing result is trivial stuff > that gets thrown away immediately. > > Linus I attach a patch which addresses some of the worst culprits here including that staging monstrosity. Changing the sDIGIT_FITTING() and uDIGIT_FITTING() macros affects a ton of other related drivers so has an outsized impact. Another big one I tackled is the NET_SKB_PAD define causing slightly hidden nesting, we can just replace that with a dumb #if and get rid of that. I also moved MVPP2_SKB_HEADROOM to a clamp_t(). I noticed a bunch of xfs stuff that's slow too, but tracked that down to <linux/bio.h> which I see you're covering in another thread with Willy. There are other bits and pieces, but this seems to cover the most egregious cases. This patch reduces preprocessor-generated output for allmodconfig from 102,966,525,841 bytes (!) to 102,764,954,617 on my system, thus saves ~200MB of generated output. ----8<----
