linux.git/scripts/mod/symsearch.c, branch v6.6.132 Clone of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git modpost: Optimize symbol search from linear to binary search 2024-04-10T14:35:47+00:00 Jack Brennen jbrennen@google.com 2023-09-26T12:40:44+00:00 2bc92c61c5417982e7b92ba628281f411d31013c [ Upstream commit 4074532758c5c367d3fcb8d124150824a254659d ] Modify modpost to use binary search for converting addresses back into symbol references. Previously it used linear search. This change saves a few seconds of wall time for defconfig builds, but can save several minutes on allyesconfigs. Before: $ make LLVM=1 -j128 allyesconfig vmlinux -s KCFLAGS="-Wno-error" $ time scripts/mod/modpost -M -m -a -N -o vmlinux.symvers vmlinux.o 198.38user 1.27system 3:19.71elapsed After: $ make LLVM=1 -j128 allyesconfig vmlinux -s KCFLAGS="-Wno-error" $ time scripts/mod/modpost -M -m -a -N -o vmlinux.symvers vmlinux.o 11.91user 0.85system 0:12.78elapsed Signed-off-by: Jack Brennen <jbrennen@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Stable-dep-of: 1102f9f85bf6 ("modpost: do not make find_tosym() return NULL") Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 4074532758c5c367d3fcb8d124150824a254659d ]

Modify modpost to use binary search for converting addresses back
into symbol references.  Previously it used linear search.

This change saves a few seconds of wall time for defconfig builds,
but can save several minutes on allyesconfigs.

Before:
$ make LLVM=1 -j128 allyesconfig vmlinux -s KCFLAGS="-Wno-error"
$ time scripts/mod/modpost -M -m -a -N -o vmlinux.symvers vmlinux.o
198.38user 1.27system 3:19.71elapsed

After:
$ make LLVM=1 -j128 allyesconfig vmlinux -s KCFLAGS="-Wno-error"
$ time scripts/mod/modpost -M -m -a -N -o vmlinux.symvers vmlinux.o
11.91user 0.85system 0:12.78elapsed

Signed-off-by: Jack Brennen <jbrennen@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Stable-dep-of: 1102f9f85bf6 ("modpost: do not make find_tosym() return NULL")
Signed-off-by: Sasha Levin <sashal@kernel.org>