a555bdd0c5
In commit 5cf0fd591f2e ("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 <masahiroy@kernel.org>
Cc: Arnd Bergmann <arnd@kernel.org>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Cristoph Hellwig <hch@lst.de>,
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Emil Velikov <emil.l.velikov@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.