On Fri, Feb 26, 2021 at 10:51 AM Arnd Bergmann <a...@kernel.org> wrote: > > On Fri, Feb 26, 2021 at 10:05 AM Sedat Dilek <sedat.di...@gmail.com> wrote: > > On Fri, Feb 26, 2021 at 9:14 AM Arnd Bergmann <a...@kernel.org> wrote: > > > > > > BTW, is CONFIG_LD_DEAD_CODE_DATA_ELIMINATION=y setable for x86 (64bit)? > > > > ( Did not look or check for it. ) > > > > > > No, in mainline, HAVE_LD_DEAD_CODE_DATA_ELIMINATION is currently > > > only selected on MIPS and PowerPC. I only sent experimental patches to > > > enable it on arm64 and m68k, but have not tried booting them. If you > > > select the symbol on x86, you should see similar results. > > > > > > > OK, i see: > > > > $ git grep HAVE_LD_DEAD_CODE_DATA_ELIMINATION arch/mips/ > > arch/mips/Kconfig: select HAVE_LD_DEAD_CODE_DATA_ELIMINATION > > > > $ git grep HAVE_LD_DEAD_CODE_DATA_ELIMINATION arch/powerpc/ > > arch/powerpc/Kconfig: select HAVE_LD_DEAD_CODE_DATA_ELIMINATION > > > > So, I need to add this to arch/x86/Kconfig. > > > > You happen to know if changes to arch/x86/kernel/vmlinux.lds.S > > (sections) are needed? > > No idea. I'm still debugging a possible regression on arm64, but both > issues I found for arm64 are specific to that architecture and won't > happen on x86. It's likely that something else breaks though. >
My first experiences with gc were with the freetz project (mips embedded router) and don't ask me what GCC version. I will try with gc + trim + cfi later after my current build has finished. > > Last question: > > The last days I see a lot of fixes touching inlining with LLVM/Clang > > v13-git. > > What git tag are you using? > > What are your experiences? > > Pending patches (kernel-side)? > > > > I use: > > $ /opt/llvm-toolchain/bin/clang --version > > dileks clang version 13.0.0 (https://github.com/llvm/llvm-project.git > > c465429f286f50e52a8d2b3b39f38344f3381cce) > > This is what I have on the build box: > Ubuntu clang version > 13.0.0-++20210223104451+ebca13c66504-1~exp1~20210223095200.234 > Distro-clang takes much longer here. Selfmade stage1-only LLVM toolchain compiles here 10% faster. cfi takes approx. 20% longer. With trim + gc I suppose it will take much longer. Let me test. Will report later. - Sedat -
