On Wed, 12 Jul 2017, Andi Kleen wrote: > Nicholas Piggin <npig...@gmail.com> writes: > >> > >> I think we should aim for gc-sections to be used by default and have LTO > >> as a possible option only. > > > > I agree after it starts getting implemented and debugged by small > > system users, we could make it default in the interest of sharing > > testing and reducing combinations. > > From what i understand the main drawback in the past was > is that various linker versions become very slow with thousands of > sections. > > So it may cost you built time. For a special small build it's probably > ok, but you wouldn't want to make it default. > > Also usually it's only useful without modules because if you > use modules EXPORT_SYMBOL pulls in a lot of unused functions.
I created CONFIG_TRIM_UNUSED_KSYMS mainly to avoid that issue. It is highly effective with either gc-sections and LTO. Nicolas
