When hacking it is a waste of time and compute energy that we need to rebuild much kernel code just for changing the head git commit, like this: > touch include/generated/utsrelease.h > time make -j3 mkdir -p /home/john/mnt_sda4/john/kernel-dev2/tools/objtool && make O=/home/john/mnt_sda4/john/kernel-dev2 subdir=tools/objtool --no-print-directory -C objtool INSTALL libsubcmd_headers CALL scripts/checksyscalls.sh CC init/version.o AR init/built-in.a CC kernel/sys.o CC kernel/module/main.o AR kernel/module/built-in.a CC drivers/base/firmware_loader/main.o CC kernel/trace/trace.o AR drivers/base/firmware_loader/built-in.a AR drivers/base/built-in.a CC net/ethtool/ioctl.o AR kernel/trace/built-in.a AR kernel/built-in.a AR net/ethtool/built-in.a AR net/built-in.a AR drivers/built-in.a AR built-in.a ... Files like drivers/base/firmware_loader/main.c needs to be recompiled as it includes generated/utsrelease.h for UTS_RELEASE macro, and utsrelease.h is regenerated when the head commit changes. Introduce global char uts_release[] in init/version.c, which this mentioned code can use instead of UTS_RELEASE, meaning that we don't need to rebuild for changing the head commit - only init/version.c needs to be rebuilt. Whether all the references to UTS_RELEASE in the codebase are proper is a different matter. For an x86_64 defconfig build for this series on my old laptop, here is before and after rebuild time: before: real 0m53.591s user 1m1.842s sys 0m9.161s after: real 0m37.481s user 0m46.461s sys 0m7.199s Sending as an RFC as I need to test more of the conversions and I would like to also convert more UTS_RELEASE users to prove this is proper approach. John Garry (4): init: Add uts_release tracing: Use uts_release net: ethtool: Use uts_release firmware_loader: Use uts_release drivers/base/firmware_loader/main.c | 39 +++++++++++++++++++++++------ include/linux/utsname.h | 1 + init/version.c | 3 +++ kernel/trace/trace.c | 4 +-- net/ethtool/ioctl.c | 4 +-- 5 files changed, 39 insertions(+), 12 deletions(-) -- 2.35.3
