From 7d7842ba31deec3a66cc0e009d19f7dd72757e17 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Wed, 24 Feb 2021 08:57:06 -0800 Subject: [PATCH] Kbuild: enable TRIM_UNUSED_KSYMS again, with some guarding In commit cc68d82c9c49 ("Kbuild: disable TRIM_UNUSED_KSYMS option") I disabled this option because it's hugely expensive at build time, and I questioned how much use it gets. Several people piped up and convinced me it's actually useful, so instead of disabling it entirely, it now depends on EXPERT and gets disabled by COMPILE_TEST builds so that 'allmodconfig' style things don't enable it. I still hope somebody will take a look at the build time issue, because as Arnd also noted: "However, the combination of thinlto and trim indeed has a steep cost in compile time, taking almost twice as long as a normal defconfig (gc-sections makes it slightly faster)" Cc: Masahiro Yamada Cc: Arnd Bergmann Cc: Jessica Yu Cc: Cristoph Hellwig , Cc: Miroslav Benes Cc: Emil Velikov Signed-off-by: Linus Torvalds --- init/Kconfig | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/init/Kconfig b/init/Kconfig index ba8bd5256980d..c2a18f56e944d 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -2273,8 +2273,8 @@ config MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS If unsure, say N. config TRIM_UNUSED_KSYMS - bool "Trim unused exported kernel symbols" - depends on BROKEN + bool "Trim unused exported kernel symbols" if EXPERT + depends on !COMPILE_TEST help The kernel and some modules make many symbols available for other modules to use via EXPORT_SYMBOL() and variants. Depending -- 2.39.5