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Masahiro Yamada 87fef8f6f2 tools: fix annoying "mkdir -p ..." logs when building tools in parallel
[ Upstream commit d1d0963121 ]

When CONFIG_OBJTOOL=y or CONFIG_DEBUG_INFO_BTF=y, parallel builds
show awkward "mkdir -p ..." logs.

  $ make -j16
    [ snip ]
  mkdir -p /home/masahiro/ref/linux/tools/objtool && make O=/home/masahiro/ref/linux subdir=tools/objtool --no-print-directory -C objtool
  mkdir -p /home/masahiro/ref/linux/tools/bpf/resolve_btfids && make O=/home/masahiro/ref/linux subdir=tools/bpf/resolve_btfids --no-print-directory -C bpf/resolve_btfids

Defining MAKEFLAGS=<value> on the command line wipes out command line
switches from the resultant MAKEFLAGS definition, even though the command
line switches are active. [1]

MAKEFLAGS puts all single-letter options into the first word, and that
word will be empty if no single-letter options were given. [2]
However, this breaks if MAKEFLAGS=<value> is given on the command line.

The tools/ and tools/% targets set MAKEFLAGS=<value> on the command
line, which breaks the following code in tools/scripts/Makefile.include:

    short-opts := $(firstword -$(MAKEFLAGS))

If MAKEFLAGS really needs modification, it should be done through the
environment variable, as follows:

    MAKEFLAGS=<value> $(MAKE) ...

That said, I question whether modifying MAKEFLAGS is necessary here.
The only flag we might want to exclude is --no-print-directory, as the
tools build system changes the working directory. However, people might
find the "Entering/Leaving directory" logs annoying.

I simply removed the offending MAKEFLAGS=<value>.

[1]: https://savannah.gnu.org/bugs/?62469
[2]: https://www.gnu.org/software/make/manual/make.html#Testing-Flags

Fixes: ea01fa9f63 ("tools: Connect to the kernel build system")
Fixes: a50e433327 ("perf tools: Honor parallel jobs")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Daniel Xu <dxu@dxuuu.xyz>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2025-02-21 14:01:22 +01:00
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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 reStructuredText 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.